Search

Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4 g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2 g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture. [ABSTRACT FROM AUTHOR]

Diets rich in readily fermentable carbohydrates primarily impact microbial composition and activity, but can also impair the ruminal epithelium barrier function. By combining microbiota, metabolome, and gene expression analysis, we evaluated the impact of feeding a 65% concentrate diet for 4 weeks, with or without a phytogenic feed additive (PFA), on the rumen ecosystem of cattle. The breaking point for rumen health seemed to be the second week of high grain (HG) diet, with a dysbiosis characterized by reduced alpha diversity. While we did not find changes in histological evaluations, genes related with epithelial proliferation (IGF-1, IGF-1R, EGFR , and TBP) and ZO-1 were affected by the HG feeding. Integrative analyses allowed us to define the main drivers of difference for the rumen ecosystem in response to a HG diet, identified as ZO-1, MyD88 , and genus Prevotella 1. PFA supplementation reduced the concentration of potentially harmful compounds in the rumen (e.g. dopamine and 5-aminovaleric acid) and increased the tolerance of the epithelium toward the microbiota by altering the expression of TLR-2, IL-6 , and IL-10. The particle-associated rumen liquid microbiota showed a quicker adaptation potential to prolonged HG feeding compared to the other microenvironments investigated, especially by the end of the experiment. [ABSTRACT FROM AUTHOR]

Nitrate (NO3- ) has been recognized as an effective dietary additive to reduce enteric methane (CH4) production in ruminants. Two experiments were performed to evaluate the effects of long-term supplementation and method of supplementing calcium ammonium nitrate (CAN) on enteric CH4 production in Hanwoo steers. In Exp. 1, Hanwoo steers [n = 20; body weight (BW) = 348 ± 18 kg] were divided into two groups of 10, and were assigned to one of the two diets 1) CON, 500 g/kg timothy hay and 500 g/kg commercial concentrate, or 2) CAN, basal diet top-dressed with 2.5% CAN [1.578% NO3- in the dietary dry matter (DM)] for 115 d in a completely randomized design. Measurement of CH4 was performed for 3 d starting from d 21, d 51, d 80 and d 112 using whole body respiratory chambers (RC). Rumen fluid and blood samples were collected on d 25 and d 26 of the feeding trial, respectively. In Exp. 2, the animals were re-grouped (476 ± 21 kg) and fed the same basal diet supplemented with 2.0% CAN (1.262% NO3- in the dietary DM) incorporated in the concentrate pellet (P-CAN). Methane was measured on d 19 and d 45 for 3 d. In Exp. 1, CAN supplementation decreased (P < 0.05) DM intake (DMI) of the steers both in the barn and RC. However, no negative effects on average daily gain or feed conversion ratio were observed. Also, no potential toxicity of NO3- was observed based on blood methemoglobin concentrations (all samples < 2.5% of total hemoglobin). A decrease (P < 0.05) in CH4 production (g/d) caused by decreased DMI was noted in CAN throughout the feeding trial. However, CH4 yield (g/kg DMI) decreased (P < 0.05) only in the beginning phase (d 21) and did not differ (P > 0.05) thereafter. Ruminal pH, ammonia and total volatile fatty acid concentration did not differ between treatments (P > 0.05), but CAN increased and decreased (P < 0.0001) acetate and butyrate proportions, respectively. Steers fed CAN had greater ruminal abundance of Ruminococcus sp. (P < 0.05), Succiniclasticum (P = 0.066), and Selenomonas ruminantium (P = 0.073), but a reduced (P < 0.05) abundance of Methanobrevibacter ruminantium (P = 0.073). In Exp. 2, P-CAN did not exert any effects on DMI, CH4 production, CH4 yield and other production parameters. Overall, CAN can be used as a feed additive for beef cattle in the long-term without NO3- intoxication or any negative effects on growth performance. However, lack of persistent decrease in CH4 yield suggested the need of further evaluation of CAN under different dietary conditions. Furthermore, incorporating CAN in the concentrate pellet can be a suitable approach, since top-dressing may alter the organoleptic properties of diets that may reduce DMI of the steers. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effects of a phytogenic additive (Digestarom Prime, dsm-firmenich, Switzerland) on performance and supplement in- take of growing grazing Nellore young bulls from November 2021 to April 2022. Animals [n = 120; initial body weight (BW) = 280 kg and age = 14 mo] were equally distributed in six paddocks (7.7 ha each) of B. brizantha cv. Marandu (20 animal/paddocks) equipped with electronic feeders that provided individual access (Intergado system). The experiment was conducted in a complete randomized design, with 20 replicates (animals) per treatment. Treatments consisted of a protein supplement (Fosbovi Proteico 30, DSM, Brazil), provided ad libitum, with or without the addition of Digestarom Prime, in a dose adjusted to ensure a daily intake of 0.2, 0.4, 0.6 or 0.8 gּ·animal-1ּ·d-1. Treatments evaluated were: 1) control (CON) with no additive; 2) monensin 15 ppm (MON); 3) Digestarom 0.2 gּ·animal- 1ּ·d-1 (D 02); 3) Digestarom 0.4 gּ·anima-1·d-1 (D04); Digestarom 0.6 gּ·animal-1ּ·d-1 (D06) and 6) Digestarom 0.8 gּ·animal-1ּ·d-1 (D08). The experiment lasted 150 d. Supplement intake was measured by electronic feeders, and intake as % of BW was calculated using the average of initial and final BW. Average daily gain (ADG) was measured by Intergado system, through the electronic weighing system installed underneath the drinkers. Data were analyzed by SAS PROC MIXED in DIC considering the initial BW as a covariate. Student’s t test was utilized for means comparison. Significance of 5% was adopted. Supplementation with Digestarom at the level of 0.6 gּ·animal-1ּ·d-1 increased ADG in approximately 0.116 kg/d (means: D06 = 1.174 kg/d vs. CON = 1.064, MON = 1.086, D02 = 1.069, D04 = 1.038 and D08 = 1.034 kg/d; P < 0.01), and final BW, in approximately 19 kg (means D06 = 459 kg vs CON = 436, MON = 439, D02 = 449, D04 = 443 and D08 = 435 kg; P < 0.05). Monensin presented the least supplement intake evaluated as either absolute or relative to BW (0.214 kg/d and 0.061% of BW, P < 0.01), followed by Digestarom levels of 0.4 and 0.8 g gּ·animal-1ּ·d-1 (D04 = 0.347 kg/d and 0.098% of BW and D08 = 0.367 and 0.103), that did not differ from each other (P > 0.05). Control, 0.2 and 0.6 Digestarom gּ·animal-1ּ·d-1 presented the greatest supplement intake (CON = 0.481 kg/d and 0.134% of BW, D02 = 0.456 and 0.123, D06 = 0.444 and 0.120, P < 0.01), that also did not differ from each other (P > 0.05). We conclude that Digestarom supplementation at 0.6 gּ·animal-1ּ·d-1 improves animal performance, without affecting supplement intake of grazing Nellore young bulls. [ABSTRACT FROM AUTHOR]

The objective was to assess the impact of combining 3-nitrooxypropanol (3-NOP; Bovaer) with different feed additives on performance, carcass characteristics and meat quality. Young Nellore bulls (n = 164), aged 16 ± 1 mo with body weight (BW) = 410 ± 3 kg, were randomly allocated to 24 pens. There were three treatments, each with 8 replications (pens) per treatment and 7 animals per pen. The animals were fed a high-concentrate feedlot diet (R:C, 10:90) for 102 d, according with the following three treatments: 1) Control: Sodium Monensin [26 mg/kg dry matter (DM)]; 2) BOV: Control + 3-NOP (Bovaer; 100 mg/ kg DM); 3) BOVPERF (Bovaer Performance pack): Control + 3-NOP (100 mg/kg DM) + Essential oils (Crina Ruminants, 100 mg/kg DM) + 25-OH-Vitamin D3 (Hy-D, 0.10 mg/kg DM) + carbo-amino-phospho- chelate of chromium and zinc (0.40 and 60 mg/kg of DM, respectively). The BW of yearling bulls were recorded at the beginning, the end of the adaptation period (28 d), and the conclusion of the experiment after a 16-h feed withholding period to facilitate the recording of shrunk BW. Based on these BW, it was possible to conduct analyses of the performance during the periods of 28 and 102 d of the experiment. Additionally, carcass characteristics were evaluated, along with assessments of the meat quality of these animals subjected to different treatments. Data were analyzed by ANOVA using the PROC MIXED of SAS 9.4 and means and contrast comparison evaluated by Tukey test at P < 0.05. Feeding BOVPERF increased DM intake during the adaptation period (P < 0.01) compared with control and BOV. However, the control group showed a greater conversion ratio (P < 0.01) and feed efficiency (P < 0.01) compared with BOV and BOVPERF at 102 d of the feedlot. There was a greater increase in hot carcass weight (HCW) with a difference of (+12 kg, P > 0.01), greater carcass ADG (+113 g/d, P < 0.01), followed by a greater dressing percentage (P < 0.01), greater carcass gain yield (P < 0.01), and better biological efficiency (- 9 kg diet in DM kg/15 kg of HCW, P = 0.02) for BOVPERF compared with control and BOV. Additionally, when analyzing meat quality characteristics, a significant difference (P < 0.01) in pH values was observed for BOVPERF compared with control and BOV. In conclusion, the combination of 3-NOP with essential oils, 25-hydroxy-vitamin D3, and minerals such as chromium and zinc demonstrated positive effects on various aspects, including increased performance, carcass characteristics and meat quality. [ABSTRACT FROM AUTHOR]

The utilization of commercial tannin extracts as feed additives holds promise for enhancing animal performance and health within commercial feedlot settings. This study aimed to assess the impact of a commercial tannin blend, SilvaFeed BX (Indunor, Buenos Aires, Argentina), sourced from quebracho and chestnut extracts along with saponins, on the performance of beef cattle. Nelore bullocks (n = 1,198) were allocated to 12 pens in a completely randomized block design, stratified by initial date, at a commercial feedlot facility in Goias State, Brazil. Each pen served as an experimental unit, with 10 pens housing 100 animals each and 2 pens containing 99 animals each. The experimental treatments included a Control diet with monensin alone [25 ppm/kg dry matter (DM)] or treated with BX (0.7 g/kg DM) on top of the control diet. Individual body weights (BW) were recorded at processing (initial BW; IBW) and shipment (final BW; FBW), while DM intake (DMI) was averaged per pen throughout the study duration. Carcass weight (CW) was individually measured at the packing plant, and carcass gain was calculated as the discrepancy between carcass weight and the estimated initial carcass weight, set at 50% of the IBW, aligning with customary practices for negotiating feeder cattle in Brazil. Statistical analyses were conducted using Proc Glimmix in SAS, treating pens and treatments as fixed effects and blocks as random effects, with IBW considered as a covariate. Residuals were assessed for normality, identifying three outliers. Mean comparisons were facilitated using LSMEANS. The results indicated that BX-treated cattle exhibited increased FBW (502.17 vs. 493.64 kg, P = 0.0992), carcass weight (275.76 vs. 268.78 kg, P = 0.0343), total carcass gain (107.52 vs. 100.54 kg, P = 0.0343), and improved carcass feed conversion (10.46 vs. 11.45 kg DM/kg; Table). Despite numerical differences, the limited number of replications were not enough to detect significant differences between treatments in average daily gain (P = 0.2419), DMI (P = 0.5508), feed conversion (P = 0.2641), or dressing (P = 0.3757). In conclusion, BX, a blend of tannins, exhibits potential for enhancing carcass weight and feed conversion efficiency in Nelore bullocks. Further investigations employing larger sample sizes are warranted to comprehensively elucidate its effects on other performance parameters. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate increasing levels of a tannin-based product and a monensin (positive control; unique dose) using a dual-flow continuous-culture system. Diets were randomly assigned to ten fermenters in a replicated 5 x 5 Latin square with three, 10-d experimental periods consisting of 7 d for adaptation and 3 d for sample collection. Four different levels were tested independently, resulting in 5 treatments: tannin at levels of 0 (negative control), 0.07, 0.14, and 0.21 (% of DM of the total diet) and monensin as positive control at 28 mg/ kg DM. The tannin-based product was a specific blend of tannin and saponins, composed of quebracho and chestnut tannin extracts, SilvaFeed-BX). Diets were prepared as concentrate mixes that were combined with sugarcane bagasse, corn grain, dry distillers grain, citrus pulp, peanut meal, and urea. Liquid and solid flow rates were adjusted to 10 and 5.0%/h, respectively. Samples were collected for digestibility, ruminal fermentation, and microbial growth. The basal diet consisted of a typical finishing diet for beef cattle (16:84 roughage:concentrate ratio). All results were assessed for residual normality and variance homogeneity. All variables were fitted through generalized mixed models (GLIMMIX procedure) and compared by using Tukey test (multiple comparison) and polynomial regressions (tannin concentrations, which were analyzed for linear and quadratic responses. Partial data were presented in the table below. Total VFA concentration, molar proportion of butyrate, and total Branched-chain VFA were not affected by treatments (P > 0.05). Molar proportion of acetate of the tannin-based product at 0.07 % of DM tended to be decreased compared with all other treatments. Molar proportion of propionate increased quadratically (P = 0.05) reaching the peak at the level of 0.07 % of DM, which were greater than monensin treatment. In conclusion, our results indicate that a smaller dose of a tannin-based product (0.07 g/ kg of DM) might manipulate ruminal fermentation by increasing molar proportion of propionate in typical feedlot diet fed under tropical conditions. This is important from an energetic standpoint for the animal host, since propionate is the precursor of glucose synthesis in ruminants. [ABSTRACT FROM AUTHOR]

The ability of some essential oils not to depress dry matter intake (DMI) is recognized, a marked effect when supplementation with sodium monensin is used; favoring DMI in wk 1 in the feedlot has a great impact on ingestive behavior in the subsequent weeks and on average daily gain (ADG) for the total period. The objective of the study was to evaluate performance and feed consumption in the first 30 d of feedlot, using different feed additives. Nelore bulls [n = 48; initial body weight (BWi) = 378.1 kg ± 8.92 kg; 20 mo of age] were used. Bulls were allocated in a collective pen, randomly distributed into two treatments, with the animal being the experimental unit. The treatments were: 1) Sodium Monensin (MON), 26 mg/kg DM; and 2) CRINA + RUMISTAR + Hy-D (CRD), blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25 hydroxy-vitamin D3, 1 mgּ animal-1ּ d-1. The animals were weighed fasting (± 16h) at the beginning of the experiment and weighed in the fed state on d 31, with 4% shrink deducted to account for the contents of the gastrointestinal tract. DMI was measured daily and individually using electronic troughs with selector doors (Intergado, PONTA, Betim, MG-Brazil), capable of identifying and allowing access to the animals through an earring with a transponder. The adaptation period lasted 15 d, with increasing levels of concentrate inclusion, being 5 d (72% concentrate), 5 d (75.8% concentrate), and 5 d (83.3% concentrate), being that between d 16 and 30 the finishing diet (89.3% concentrate) was offered, consisting of ground corn, rehydrated corn grain silage, cottonseed meal, whole cottonseed, sugarcane bagasse, urea, and vitamin-mineral supplement. The DMI was evaluated in two periods (d 0 to 15 = adaptation; d 0 to 30 = first 30 d). Data were analyzed by SAS PROC ANOVA, using BWi as a covariate when significant. Animals fed CRD had greater BW at d 30 (425 vs 417 kg, P = 0.04) and increased ADG by 0.260 kg/d (1.56 vs 1.30 kg/d, P = 0.04). The DMI at adaptation (7.96 kg/d, P = 0.90), and in the first 30 d (8.67 kg/d, P = 0.33) and in the first 30 d in relation to BW (2.18 % of BW, P = 0.46) were similar between treatments; however, CRD tended to provide a better feed efficiency (0.179 vs 0.153, P = 0.09). These findings suggest that the use of CRD may be an effective strategy to enhance feedlot cattle performance during the adaptation period, when fed diets containing rehydrated corn grain silag [ABSTRACT FROM AUTHOR]

An experiment was carried out with the objective of evaluating the effects of the addition of humic substances (HS) from vermicompost in the feed on the histology measurements and number of goblet cells in the jejunal villus in piglets at weaning. Piglets (n = 200) were housed in groups of five in elevated pens and were assigned to one of four treatments: 1 = Positive control diet (PC) with antibiotic growth promoter (AGP), 2 = Negative control diet (NC) without AGP, 3 and 4 = Diets without AGP added with 2500 and 5000 ppm HS, respectively. HS were extracted from a vermicompost made of sheep and pig manure using an alkaline solution and added in dry form to the feed. A basal sample of 5 cm of jejunum was taken from 10 piglets at weaning; the same was done on d 3 and 7 post-weaning, selecting 5 piglets per treatment. The samples were processed to apply different stains: () eosin and hematoxylin for morphometric analysis: villus height, villus thickness, villus area, crypt depth and the villus eight to crypt depth ratio; 2) Pass Schiff to quantify neutral goblet cells; 3) Alcian Blue pH 1.0 for heavily sulfated goblet cells; and 4) Alcian Blue pH 2.5 for non-sulfated acid goblet cells. Ten villi per animal were evaluated. Images were analyzed with Leica interactive measurement software. The results were subjected to ANOVA in a randomized complete block design. Regarding the histology of villus in the jejunum, on d 3 post-weaning the pigs added with HS had a greater villus height (3 = 317.75, 4 = 310.46 vs 2 = 278.08 and 1 = 307.12 µm; P < 0.05; SEM = 10.86), villus width (3 = 94.64, 4 = 95.04 vs 2 = 85.39, and 1 = 93.51 µm; P < 0.01; SEM = 2.32); and villus area (3 = 95841, 4 = 93678 Vs 2 = 76646 and 1 = 93471 µm2; P < 0.01; SEM = 4343), compared with the NC. The crypt depth was greater in piglets added with HS (3 = 236.78, 4 = 241.85 vs 1 = 194.65 and 2 = 203.01 µm; P < 0.01; SEM = 6.57) compared with the PC and NC. On d 7 postweaning, the piglets added with HS showed greater villus height (3 = 293.24, 4 = 282.45 vs 1 = 258.95 and 2 = 253.03 µm; P < 0.01; SEM = 7.89); villus area (3 = 101354, 4 = 94,575 vs 1 = 85,633 and 2 = 82,125 µm2; P < 0.01; SEM = 3818) and crypt depth (3 = 326.82, 4 = 337.28 vs 2 = 283.88 and 1 = 321.53 µm; P < 0.01; SEM = 8.285) compared with the PC and NC. The number of neutral, heavily sulfated and non-sulfated goblet cells at 3 and 7 d post-weaning were significantly reduced in all treatments compared with weaning; but with the addition of HS a greater number (P < 0.05) of goblet cells per villus were shown. The results suggest that HS from vermicompost improves the intestinal morphometry and increases the number of goblet cells that produce protective intestinal mucus at 3 and 7 d post-weaning in pigs. [ABSTRACT FROM AUTHOR]

Heat stress decreases pig productivity and welfare by reducing feed intake and growth, increasing oxidative stress, and compromising gut health. Feed additives with anti-inflammatory and antioxidant properties could help pigs cope with the negative impact of heat stress. The study evaluated the efficacy of feeding diets containing betaine and a plant-based antioxidant blend (AOB) on the growth performance and carcass quality parameters of commercially housed fattening pigs under heat-stress conditions. The study design was a randomized completed block with 2 dietary treatments using 836 pigs [starting body weight (BW) = 22.7 ± 3.8 kg) and 22 replicate pens/treatment (19 mixed-sex pigs/pen). The treatments were a standard four-phase commercial grow-finish corn-soy based diet (Control) and Control plus 1 kg/MT each of betaine and AOB (BetAOB). Pigs were subjected to a heat stress challenge by increasing the ambient temperature from 18 to 29°C for 8 pigs/d (1000 to 1800 h) from d 10 to 42 and d 85 to 106 of the study. Body weight and feed disappearance of each pen were recorded before and after the heat stress challenge and every third week to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Morbidity and mortality were recorded daily. Data were analyzed using PROC GLMMIX of SAS with appropriate models for the different data distributions. Pen was the experimental unit. The overall herd mortality was 1.3% and 0.7% of pigs received medical treatment for leg problems. Treatment did not affect the percentage of pigs culled (P = 0.48; Control = 6.7% vs. BetAOB = 5.7%). Pigs fed BetAOB tended to have a decreased FCR (-0.06 kg/kg; P = 0.10) during the first heat stress challenge (d 22 to 42). Further, BetAOB-fed pigs had decreased FCR (-0.07 kg/kg; P = 0.02) and tended to have a greater ADG (+28 g/d; P = 0.07) from d 43 to 61. Pigs fed BetAOB tended to have decreased ADFI (-89 g/d; P = 0.06) from d 62 to 84. Consequently, pigs fed BetAOB had less (P = 0.04) overall FCR compared with the Control (2.53 vs. 2.48 kg/kg). Treatment did not affect carcass weight (P = 0.76), carcass yield (P = 0.76), or any of the carcass quality parameters measured (all P > 0.11). In summary, under heat-stress conditions, pigs receiving a diet containing 1 kg/MT each of betaine and AOB had better feed efficiency than those receiving the Control diet. Therefore, feeding finishing pigs diets supplemented with betaine and the antioxidant blend can help minimize the negative effect of heat stress by improving feed efficiency. [ABSTRACT FROM AUTHOR]

Boar taint is a urine or feces-like odor that occurs when meat from entire male pigs is heated and is caused primarily by the deposition of androstenone in the fat. Androstenone is thought to circulate in the body similarly to sex steroids; this may facilitate the recirculation of androstenone to the liver or systemic circulation for deposition in the fat. Previous studies from our lab concluded that feeding activated charcoal (AC) can reduce the accumulation of androstenone in fat. However, this is not a practical solution as AC is expensive and not approved for use in livestock feed. Biochar is a charcoal-based adsorbent that is approved as a feed additive and has similar physical binding properties to AC, such as high porosity and large surface area. Our in vitro binding studies showed similar binding efficiency between AC and biochar for androstenone; however, the efficacy of biochar for reducing boar taint has not been assessed in vivo. Therefore, the objective of this study was to compare the efficacy of biochar and AC as dietary treatments for reducing fat androstenone concentrations. Beginning at 71.3 ± 1.3 kg, [(Yorkshire x Landrace) x Duroc] boars (n = 34) were acclimated to a standard corn and soybean meal-based finisher diet, for 1 wk. Animals were then randomly assigned to a finisher diet containing 5% AC (n = 17) or 5% biochar (n = 17) for 4 wk, followed by a 2-wk recovery period on the standard finisher diet. Backfat biopsies were performed bi-weekly and fat androstenone concentrations were quantified using an androstenone-specific enzyme-linked immunosorbent assay. All animals were evaluated on the change in fat androstenone concentrations quantified at the end of the treatment and recovery period. Boars with increased fat androstenone concentrations at the end of recovery were classified as having a positive response to the treatment. Statistical analysis was performed using a Student’s t-test to evaluate differences in fat androstenone concentrations between the end of treatment and recovery periods in animals with positive treatment responses. Fat androstenone concentrations at the end of treatment were 1.721 ± 0.152 μg/mL and 1.431 ± 0.412 μg/ mL for AC (n = 9) and biochar (n = 6), respectively; these values significantly increased to 5.475 ± 0.804 μg/ mL (P = 0.0003) for AC and 3.924 ± 0.586 μg/mL (P = 0.004) for biochar at the end of recovery. Moreover, concentrations of androstenone in the fat at the end of treatment and recovery were similar between AC and biochar treatments. These findings demonstrate that biochar can decrease fat androstenone concentrations in some mature boars, with comparable efficacy to that of AC. However, additional work is needed to identify biomarkers associated with positive treatment responses so that biochar can be provided in a targeted manner to boars that will respond favorably. [ABSTRACT FROM AUTHOR]

A feedlot study was conducted to evaluate the effect of two feed additives, Prime Force (Furst- McNess Company, Rockford, IL) and Optipartum C+ (AB Vista, Plantation, FL), on finishing cattle performance and carcass characteristics. In this experiment, steers [n = 320; 390 ± 9.5 kg of body weight (BW)] were used and four treatments were evaluated in a total of 32 pens, with 10 steers per pen and 80 steers per treatment. Treatments were arranged in a 2 × 2 factorial and included a control diet with no additives; a diet containing Prime Force targeted at 68 g/ steer daily; a diet containing Optipartum C+, targeted at 20 g/steer daily; and a diet containing a combination of both products (68 g/steer Prime Force and 20 g/steer Optipartum C+). Cattle were fed for 151 d, but treatments were imposed the last 67 d before slaughter (i.e., fed control diet to all cattle until d 84). Performance is for the total 151-d feeding period. No interaction between feed additives was observed for performance or carcass traits (P ≥ 0.41), therefore main effects are presented. Feeding Prime Force increased final BW (P < 0.04) when compared with cattle not fed Prime Force. A tendency was observed for greater adjusted final BW (P = 0.06) and ADG (P = 0.08) for cattle fed Prime Force compared with cattle fed no Prime Force. Cattle fed Prime Force had numerically greater intake (P = 0.11) than cattle fed no Prime Force, therefore gain to feed (G:F) was not impacted (P = 0.54). Ribeye area and fat depth were not different (P ≥ 0.17) for cattle fed Prime Force versus cattle that had no Prime Force added to the diet, but marbling was numerically improved (P = 0.11) due to Prime Force. Carcass-adjusted final BW (P = 0.11) was numerically greater for cattle fed Optipartum C+ and ADG tended (P = 0.09) to be greater for cattle fed Optipartum C+ compared with cattle fed no Optipartum C+. Dry matter intake was not different (P = 0.54) for cattle fed Optipartum C+ versus cattle with no Optipartum C+ in the diet, therefore G:F was numerically improved (P = 0.13) by the increase in ADG for cattle fed Optipartum C+. Ribeye area, fat, and marbling were not different (P ≥ 0.30) between cattle fed Optipartum C+ and those that did not receive Optipartum C+ in the diet. Incidence of liver abscesses was not affected by feeding either additive (P = 0.40). Based on results from this study, adding Prime Force to a finishing diet tended to improve BW and ADG compared with cattle not fed Prime Force. Feeding Optipartum C+ tended to increase ADG and improve G:F due to equal DMI when compared with diets with no Optipartum C+ added. [ABSTRACT FROM AUTHOR]

Adequate water intake is linked to greater dry matter intake, heat loss, and productivity. To measure the water intake of beef cattle reared in groups, two experiments were carried out in Brazil (South East/ Middle East) using water throughs coupled with scales (Intergado, Betim, Brazil) and RFID individual identification systems, allowing the recording of individual water intake of animals. In experiment 1, young bulls (n = 96; 105 d on feed - feedlot) were randomly assigned to four treatments: 1) Control, no yeast derivative; 2) AY – 7 g·animal-1·d-1, Autolyzed Yeast grown on sugarcane molasses (RumenYeast, ICC, Brazil); 3) YM – 3 g·animal-1·d-1, yeast rich in soluble Yeast Metabolites; 4) YB – 5 g·animal-1·d-1, Yeast Blend (live Yeast plus autolyzed Yeast). Diets (adaptation, growing, and finishing) x treatments were treated as fixed effects on the complete randomized design. In experiment 2, backgrounding bull calves (n = 32) reared on grazing and 710 g/d of protein supplements (90 d) were randomly assigned to two treatments: 1) Control, no yeast derivative; 2) AY – 7 g·animal-1·d-1, Autolyzed Yeast (RumenYeast), the means were subjected to ANOVA analyses. In both experiments, additives were inserted into the diet (mineral premix or supplement), animals were the experimental unit, and differences were declared significant at P < 0.05. Yeast derivatives increased (P < 0.05) water intake in both experiments (Figure 1). The average increment in water intake (L·animal-1·d-1 was 13.9%. Interestingly, the increment in relation to control was noted for all yeast derivatives and scenarios covered by the experiments (feedlot adaptation diet, feedlot growing diet, feedlot finishing diet, and grazing system). Until now, there seems to be no literature explanation for our findings. However, these results could help to explain the positive effects of yeast derivatives on rumen pH, protein microbial flow, and thermal stress since greater water intake increases the passage rate of rumen fluid and body heat loss. Statistical correlations may not be understood as a cause-consequence link. However, when dealing with a new question, correlations may give us a path to go on and investigate. Malheiros et al. (2023) noted a negative correlation between water intake and rumen dimethylamine. Autolyzed yeast can strongly decrease the concentration of rumen methylamines in cows facing subacute acidosis (Humer et al., 2018). Niacin metabolism should also be investigated since its supplementation enhances cows’ blood niacin levels and water intake. Yeast derivatives are rich in niacin, and autolyzed yeast supplementation can increase blood niacin and body heat loss during summer (Dias et al., 2018), probably increasing water need. In conclusion, yeast derivatives increased the water intake of beef cattle, and this finding adds to the understanding of how yeast derivatives supplementation benefits ruminants. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to evaluate the effects of a phytogenic feed additive (PHYT) on the health and performance of newly-received, high-risk calves. Auction market derived crossbred beef steers and bulls (n = 712; initial body weight; BW = 239 ± 6.8 kg) were stratified by sex, blocked by BW, and randomly allocated to experimental treatments (n = 9 pens per treatment; n = 24 to 29 calves per pen). Experimental treatments included: a control diet (CON), 250 mg · steer-1 · d-1 of PHYT (PHYT250), or 500 mg · steer-1 · d-1 of PHYT (PHYT500). Pen served as the experimental unit for all dependent variables. Contrasts were performed for PHYT inclusion (PHYT250 and PHYT500 vs. CON). No differences in BW existed between treatments throughout the experiment (P ≥ 0.20; PHYT vs. CON P ≥ 0.11). In the overall model, no differences (P ≥ 0.23) in average daily gain (ADG) existed between CON, PHYT250, or PHYT500. However, when comparing PHTY to the CON, ADG tended to be less in the calves receiving CON from d 0 through d 14 (P = 0.09). No differences in dry matter intake (DMI) existed between treatments throughout the experiment (P ≥ 0.27; PHYT vs. CON P ≥ 0.13). While there was no difference in gain to feed (G:F) in the overall model (P ≥ 0.26), the tendency observed for a difference in ADG from d 0 through d 14 did result in a similar tendency for G:F across the same interval when comparing PHYT to the CON (PHYT vs. CON P ≥ 0.10). A difference was observed in the percentage of steers treated once for bovine respiratory disease (BRD; P = 0.02), with CON being treated more frequently than PHYT500, while PHYT250 was intermediate and similar to both CON and PHYT500. When comparing PHYT to the CON, there was a decrease in the percentage of steers receiving PHYT to be treated once for BRD (P = 0.01). However, there were no differences in either the percentage of steers treated twice for BRD or the in the percentage of total BRD treatments administered (P ≥ 0.29; PHYT vs. CON P ≥ 0.14). The mortality percentage and the percentage of steers removed from the study were not different (P ≥ 0.16; PHYT vs. CON P ≥ 0.14); however, there tended to be more combined mortalities and removals for steers receiving PHYT than the CON (P = 0.08; PHYT vs. CON P = 0.09), with PHYT500 and CON tending to be different, and PHYT250 being intermediate and similar to both PHYT500 and CON. In summary, PHYT did not impact overall performance, but did reduce initial antimicrobial treatments for BRD. [ABSTRACT FROM AUTHOR]

Nellore bulls [n = 22,500; Initial body weight (BW) = 400.39 ± 24.39 kg] were used to evaluate the effects of feeding different additives on growth performance and carcass production by feedlot beef cattle in a commercial feedyard (Fazenda Conforto, Nova Crixás – Goiás, Brazil). Animals were ranked by arrival date, ascending order of BW, number of animals in the pen, and assigned to 5 blocks based on initial BW. The animals within the block were randomly assigned to 102 pens, and pens were assigned randomly to 1 of 2 dietary treatments within block; thus, treatments were replicated in 51 pens. Treatments were arranged in a randomized complete block design, as following 1) MON+VM - Sodium Monensin (MON, 27 mg/ kg DM, Elanco Animal Health, Indianapolis, IN), + Virginiamycin (VM, 25 mg/kg DM, Phibro Animal Health Corporation, Guarulhos, São Paulo), and 2) Crina+Hy-D (Crina Ruminants; a blend of essential oils, 90 mg/kg DM + Hy-D;25-hydroxy-vitamin-D3 at 1 mg animal-1 d-1 (DSM Nutritional Products, Basel, Switzerland). Cattle were fed a high-concentrate diet (R:C; 15:85) for 118 d on average. Data were analyzed using PROC MIXED of SAS and means were separated using the PDIFF statement, adopting P < 0.05. Pen was the experimental unit, treatment was a fixed effect, and block was a random effect, with the Kenward- Roger adjustment included for degrees of freedom. Feeding Crina+HyD increased dry matter (DM) intake by 0.47 kg (10.23 kg vs. 9.76 kg; P = 0.0004), improved average daily gain (ADG) by 0.09 kg (1.58 vs. 1.49 kg/d; P < 0.0001) and final BW weight by 10 kg (586 vs. 576 kg; P = 0.01; Table 1) compared with animals fed MON+VM. In addition, animals fed Crina+Hy-D had heavier hot carcass weight by 8 kg (336 vs. 328 kg; P = 0.002), greater dressing percentage by 0.4 percent points (57.4 vs. 57.0%; P = 0.02), and greater average daily carcass gain by 0.07 kg (1.16 vs. 1.09 kg; P < 0.0001) compared with animals fed MON+VM. Feed efficiency (G:F; ~0.155; P = 0.54) and carcass conversion, calculated as kg of DM per each 15 kg of carcass produced (~133.73 kg; P = 0.63) were similar between the treatments. In conclusion, feeding Crina+Hy-D can be used as a strategy to increase carcass production by feedlot cattle, and to dismiss use of antibiotic and growth promotant usage in diets. [ABSTRACT FROM AUTHOR]

Poultry diets provide components that alter gut microbiota composition. We investigated antimicrobial resistance (AMR) phenotypes of E. coli isolates from ceca digesta of pullets and hens reared at different spacing allowance (SA) and dietary source of omega-3 fatty acids (N-3 FA) and yeast bioactives (YB) from placement to 17 wk of age (woa). A total of 2,632-day old chicks were placed in cages at two SA (24 cages each): High SA (HSA, 348 cm2 /bird; ~50 birds/ cage) and Low SA (LSA, 284 cm2 /bird; ~68 birds/cage). Birds were fed corn and soybean-based diets (C), C + 3% co-extruded full fat flaxseed and pulse mixture (N-3 FA) and C + 0.05% YB processed with β-1,3-glucan hydrolase. At 4, 16 and 35 woa, ceca samples were collected to isolate E. coli using Chromocult agar. Their susceptibility to 14 antibiotics were determined by automated Sensititre system according to CLSI and CIPARS guidelines to determine their antimicrobial susceptibility profile. Number of antibiotics resistant E. coli isolates were analyzed using general linear mixed model procedure of SAS with diets, SA, sampling age and associated interactions as fixed factors. Cochran-Mantel-Haenszel test was used to determine the relationship between these treatments, and differences between treatments were considered significant at P < 0.05. Out of 428 presumptive E. coli isolated, 153 of 428 isolates (35.7%) were resistant to one antimicrobial class but no resistance against ciprofloxacin, azithromycin and nalidixic acid were detected. The prevalence of antimicrobial resistant E. coli decreased as the birds aged from wk 4–35 (P < 0.05). At wk 4 (P = 0.002) and 16 (P = 0.011), the least prevalence of ampicillin (AMP) resistance was in ceca digesta from N-3 FA-fed birds. At 35 woa, no AMP and cefoxitin (FOX) resistance were detected in birds fed YB (Table 2). At 16 woa, the prevalence of streptomycin resistance was greater in N-3 FA-fed than in YB-fed birds (P = 0.02), which was less than control-fed birds. Of the 428 isolates, 59 (13.8%) were resistant to more than two antimicrobial classes, with most from TIO-FOXAMP-TET and STR-SULF-TET. At wk-4, SA had a significant effect on multiple resistance spectrum with LSA having the lowest MDR E. coli (P = 0.02) mainly from N-3 FA-fed pullets. This study showed an overall low AMR prevalence which decreases with age of the bird. This study is the first to report that feed additives (N-3 FA or YB) influence the AMR profile of cecal E. coli in pullets and layers. Prevalence of AMP resistance was least in N-3 FA-fed birds, whereas least STEP- and SULF resistance was observed in YB-fed birds. Our next study would help understand the molecular and evolutionary aspect of this resistant E. coli and their potential to cause colibacillosis. [ABSTRACT FROM AUTHOR]

Are insects a solution for feeding ruminants? Insect Meals as Protein-rich Feedstuffs In vitro evaluation Insect meals are considered as promising alternatives to plant proteins commonly used as ruminant feedstuffs (e.g. soybean meal; SBM). Following the identified differences in legislative frameworks and the potential application of insect products, information will be provided by dividing them into protein-rich feedstuffs, lipid-rich products (differentiating full-fat meals and free oils), and other insect-derived ingredients for ruminant diets. Insects as a Source of Lipids Full-fat insect meals As mentioned above, besides their high protein content, full-fat insect meals are also rich sources of lipids, with a high variability in terms of aliphatic chain length and unsaturation level. [Extracted from the article]

Postmortem whole blood samples can differ greatly in quality where hyperlipemia is a frequent variable that can influence the results of analytical methods. The aim of this study was to investigate the influence of lipemia on postmortem analysis as well as demonstrate the usage of Intralipid in comparison to pooled postmortem lipids as matrix additives for meaningful evaluation and validation of hyperlipidemic postmortem samples. Hyperlipidemic blood samples were simulated by adding different concentrations of Intralipid or pooled authentic postmortem lipids to bovine whole blood. The hyperlipidemic blood samples were spiked with 14 benzodiazepines and five sedative and antianxiety drugs (alprazolam, clonazepam, 7-aminoclonazepam, diazepam, flunitrazepam, 7-aminoflunitrazepam, hydroxyzine, lorazepam, midazolam, nitrazepam, 7-aminonitrazepam, nordazepam, oxazepam, propiomazine, dihydropropiomazine, temazepam, triazolam, zolpidem and zopiclone). Samples were prepared with liquid-liquid extraction followed by ultra-high performance liquid chromatography–mass spectrometry. The effects of lipemia on the recovery of analytes and internal standards (ISs) were evaluated to determine the effect of, and any differences between, the two additives. Lipemia was found to cause major interference when quantifying the analytes. For most analytes, the ISs could compensate for analyte losses. However, the most hydrophilic analytes (7-amino metabolites), together with the most lipophilic analytes (propiomazine and dihydropropiomazine), were greatly affected by lipemia (<50% recovery), and the IS could not compensate for analyte losses. In general, lower analyte recoveries were observed for samples with Intralipid as a lipemic additive in comparison to those containing pooled postmortem lipids. Both Intralipid and pooled postmortem lipids showed marked effects on the analytical results. Intralipid gave a good indication of the effects of lipemia and could be a useful tool for making a meaningful evaluation of hyperlipidemic postmortem samples during the method development and validation. [ABSTRACT FROM AUTHOR]

In November of 2021, the European Food Safety Authority (EFSA) released a draft scientific opinion on bisphenol A (BPA) exposure and health outcomes released to the public. EFSA concluded that the most sensitive outcome category to BPA exposure is the immune system. In this scientific opinion, EFSA utilized a weight of evidence approach to conclude that it is likely that BPA exposure promotes the development of TH17 cell-mediated atopic respiratory disease (eg, wheezing, rhinitis and asthma). Here, we present a dissenting analysis to that put forward in the draft EFSA scientific opinion and raise concerns about the studies and EFSA's interpretation of data that were used to arrive at their conclusion. [ABSTRACT FROM AUTHOR]

Zearalenone (ZEN) is an estrogenic mycotoxin produced by the Fusarium species and induces severe reproductive disorders in animals thus a major concern in the livestock industry. Probiotic bacteria treatments have been shown to inactivate mycotoxins, therefore, in this study, we investigated the effect of two commercial probiotic feed additives on the sequestration of ZEN. Commercial probiotic blends containing clay-based binder with Aspergillus niger, Bacillus licheniformis, Bacillus pumilus , and Bacillus subtilis at various proportions from BioMatrix International were incubated with ZEN in a time-dependent manner and then analyzed by Enzyme-Linked Immunosorbent Assay (ELISA) to quantify unbound ZEN. Sequestration of ZEN was further verified by using MCF-7 cell-based cytotoxicity and/or cell proliferation assays. ZEN, or probiotic mix, was nontoxic to MCF-7 cells. Probiotic blends decreased ZEN concentration by 45% (∼100 μg L−1) and prevented ZEN from inducing MCF-7 cell proliferation (20%–28% reduction). The probiotic feed supplements tested show a potential utility in ZEN neutralization. [ABSTRACT FROM AUTHOR]

Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet. [ABSTRACT FROM AUTHOR]

We analyzed the effects of Glycyrrhiza polysaccharide (GCP) on growth performance, appetite, and hypothalamic inflammation-related indexes in broilers. One-day-old male AA broilers were randomly divided into four groups: Control , L-GCP , M-GCP , and H-GCP (0, 300, 600, and 900 mg GCP/kg feed), with six repetition cages for each treatment and 12 broilers in each repeat for a period of 42 days. From day 1 to day 21, the addition of GCP to the diet significantly improved the ADFI and the ADG of broilers, and the mRNA levels of NPY and AgRP were significantly increased while POMC and CART were decreased in the hypothalamus of broilers; GCP also significantly decreased the mRNA levels of IL-1β , IL-6 , TNF-α , TLR-4 , MyD88 , and NF-κB , and increased the IL-4 and IL-10 in the hypothalamus from day 1 to day 42. The concentrations of appetite-related factors and inflammatory factors in serum were changed in the same fashion. Supplementation with 600 mg/kg GCP had the optimal effect in broilers, and GCP has the potential to be used as a feed additive in the poultry production industry. [ABSTRACT FROM AUTHOR]

Turmeric, a common spice in many countries has been used for centuries in traditional medicine for its antimicrobial properties. Recent research has shown that turmeric can be a viable alternative to antibiotics in poultry production. Antibiotic overuse in poultry has led to the development of antibiotic-resistant bacteria, which poses a threat to both animal and human health. Turmeric contains curcumin, a compound that has been shown to have antimicrobial activity against a wide range of bacteria, including those resistant to antibiotics. In addition, turmeric has anti-inflammatory and immunomodulatory properties, which can help boost the immune system of poultry and reduce the need for antibiotics. Studies have shown that turmeric can improve growth performance, and gut health, and reduce the incidence of disease in poultry. Therefore, the use of turmeric as an alternative to antibiotics in poultry production has the potential to not only improve animal health and welfare but also contribute to the fight against antibiotic resistance. This review aims to provide an overview of the recent knowledge on the use of these plant extracts in poultry feeds as feed additives and their effects on poultry performance. [ABSTRACT FROM AUTHOR]

A total of 120 Nellore bulls, [initial body weight (BW) = 307 ± 11.6 kg and 12 mo of age] were allocated into 12 collective pens (10 bulls per pen) in a commercial feedlot to evaluate the effects of a specific blend of tannin and saponins on enteric methane (CH4) emissions. The study was a completely randomized design, in which pens were considered the experimental units (N = 6 pens per treatment) and were randomly allocated into one of two treatments: 1) Control (CON), a basal diet with monensin supplementation (25 mg/kg dry matter [DM]; Rumensin, Elanco Animal Health, Greenfield, IN, USA), or 2) Control + a specific blend of tannin and saponins (TAN; 0.7 g/kg DM; composed of quebracho and chestnut tannin extracts along with carriers from cereals rich in saponins; SilvaFeed BX, Silvateam, San Michele Mondovi, CN, Italy). After the adaptation period (20 d), the experiment was divided into two phases: growing phase (21 to 53 d; total of 33 d) and fattening phase (54 to 139 d; total of 86 d). Enteric methane emissions were estimated using the sulfur hexafluoride (SF6) tracer gas technique. Interactions between treatment and period (growing vs. fattening) were detected for daily CH4 emissions, in which animals fed TAN reduced CH4 emissions by 17.3% during the fattening period compared to bulls fed CON (P = 0.05). In addition, bulls fed TAN had lower CH4 emissions expressed by dry matter intake (DMI) during the fattening period compared to bulls fed CON (P = 0.06). The findings presented herein indicate that a specific blend of tannin and saponins can be used as a strategy to reduce enteric CH4 emissions and its intensity of Nellore bulls finished in feedlot systems under tropical conditions. [ABSTRACT FROM AUTHOR]

Fifty-nine Angus-cross steers (492 ± SD 36 kg) were arranged in a randomized complete block design and assigned to the following dietary treatments for the final 106 days of the finishing phase: no supplementation (CON), 0.5% benzoic acid (ACD), 3 g/steer/d active dry Saccharomyces cerevisiae (YST), or both [0.5% benzoic acid and 3 g/steer/d S. cerevisiae (AY)]. Steers were slaughtered at a commercial facility where longissimus thoracis (IMPS #107 Beef Rib) samples were retrieved and evaluated for fatty acid composition, sensory attributes, and shelf-life during a simulated retail display period. Data (N = 57) were analyzed using dietary treatment as a fixed effect, blocking weight at the beginning of the study as a random effect, and steer as the experimental unit. Muscle pH and proximate composition (moisture and intramuscular lipid) for longissimus samples were not different (P ≥ 0.39) among dietary treatments. Most fatty acid profile values and calculations were not different among dietary treatments (P ≥ 0.10); however, the n -6: n -3 ratio differed (P = 0.01), with ACD samples having lower n -6: n -3 compared with CON and YST samples while AY samples were intermediate and not different from other dietary treatments. The trained sensory panel did not detect differences among dietary treatments (P ≥ 0.23) for juiciness, beef flavor intensity, or off-flavor intensity; however, they did score AY samples as chewier than ACD samples with CON and YST samples intermediate and not different from other dietary treatments. Yet, tenderness was not different when scored by trained panelists (P = 0.10) or measured instrumentally (P = 0.21). Total color change tended to differ (P = 0.09) during the 12-d simulated retail display period with AY samples experiencing less color change compared with YST samples, while CON and ACD samples were intermediate and not different from other dietary treatments. Lipid oxidation (as measured with TBARS) tended to differ (P = 0.08) following the 12-d simulated retail display period with ACD and AY samples experiencing lower levels of oxidation compared with CON, while YST samples were intermediate and not different from other dietary treatments. Overall, these results suggest there were no negative impacts on meat quality when finishing steers were supplemented with either benzoic acid or S. cerevisiae , and there may even be advantages for fatty acid composition and oxidative stability when steers were supplemented with benzoic acid. [ABSTRACT FROM AUTHOR]

Calf recovery after arrival at the rearing farm in unweaned calves is impaired by periods of stress, feed restriction and fasting during marketing and transportation. The use of feed additives to enhance intake at arrival could be a strategy to minimize those negative effects. A total of 72 calves (71.4 ± 1.72 kg) gathered in a commercial assembly center and transported 9 h to a rearing farm were used to evaluate the effect of a sensory additive (SA) on performance in calves fed 2 L of milk replacer twice daily at 12.5% and ad libitum concentrate feed. Calves were allocated in 8 pens and distributed in 2 treatments (4 pens/treatment): calves fed a concentrate without SA since the beginning of the study (arrival to the rearing farm after transport) until weaning (CON; n = 36); calves fed a concentrate containing SA (SEN; n = 36) from arrival until weaning. Calf body weight (BW) and pen intake were recorded weekly. On d 21 of the study, calves were partially weaned and only milk replacer was offered in the morning, and on d 28 all calves were completely weaned. The study lasted 35 d. Data were analyzed with a mixed-effects model. Average daily gain was greater (P = 0.04) for SEN calves compared with CON calves (0.68 ± 0.019 kg/d and 0.61 ± 0.019 kg/d, respectively). Final BW of SEN calves (95.5 ± 0.89 kg) tended (P = 0.06) to be greater compared with BW of CON calves (93.1 ± 0.89 kg). Finally, average concentrate intake was greater for SEN calves (0.89 ± 0.023 kg/d) compared with CON calves (0.79 ± 0.023 kg/d). Unweaned dairy beef calves receiving sensory additive improved concentrate intake and growth at farm arrival improving their recovery. [ABSTRACT FROM AUTHOR]

Veal calves have to deal with several stressors early in life, such as transport and commingling with animals of unknown health histories from multiple different origins; making the reception a possible critical period where animals should adapt to all these challenges. Previous studies in unweaned rosée calves have shown that the use of feed additives (FA) to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation. The aim of this study was to evaluate the effects of a palatability enhancer (PE) and olive bioactives (OB) on performance and serum biomarkers in veal calves. Dairy beef calves [n = 252; BVD-free; body weight (BW) = 44.6 ± 3.63 kg] coming from auction market were distributed in 3 treatments (84 animals/tr) during 8 wk: i) calves fed concentrate and MR without FA (negative control, NC); ii) calves fed concentrate and MR with a PE based on sweeteners (PE); and iii) calves fed concentrate with PE and MR with PE and OB (PEOB). On farm arrival animals were housed individually until 5 wk of age, when animals were grouped in pens of 4 calves. Performance was monitored during the trial and serum samples were collected 48 h after the mixing (25 animals/tr) to analyze several biomarkers related to immune system (MILLIPLEX MAP Kit) and energy status (BHBA). Performance data were analyzed with a mixed-effects model and serum biomarkers by One-Way Anova with Fisher’s LSD correction for multiple compari- sons (normally distributed data) or by non-parametric Kruskal-Wallis test with Dunn’s correction (data not normally distributed). Final BW was greater (P = 0.01) in PE and PEOB groups compared with NC (+2.2 kg and +2.6 kg, respectively). Concentrate feed intake (FI) during first 4 wk tended (P = 0.06) to be greater in PEOB compared with NC (+15%); however, after grouping (wk 5 to wk 8), PE showed a ldecreased FI compared with NC (-9.5%, P = 0.01). Forty-eight hours after animal grouping, PEOB showed reduced concentration of tumor necrosis factor (TNF) α than NC and PE (P = 0.03). Moreover, PEOB and PE had a greater concentration of interleukin (IL) 36Rα (P < 0.05) and IP10 (P < 0.01) compared with NC. Besides PEOB tended (P < 0.15) to have decreased concentrations of MIP1α, IL1α, and BHBA compared with PE. In conclusion, the addition of a PE and OB improved the adaptation of veal calves after reception, resulting in greater final BW. The improvement in early FI and the immunomodulatory effect in challenging situations displayed by the treatments may partially explain the observed benefits. [ABSTRACT FROM AUTHOR]

During the rainy season, utilizing grass-fed cattle is a common and cost-effective approach for fattening in tropical regions. Despite having access to high-quality forage, cattle often require protein-rich supplementation to optimize their performance. This study aimed to evaluate the effectiveness of a commercially available feed additive, SilvaFeed BX (Indunour, Buenos Aires, Argentina), derived from quebracho and chestnut tannin extracts along with saponins, on the performance of grazing beef cattle supplemented during the rainy season (January-May 2023) in tropical region. A total of 465 Nelore or crossbred Nelore-Angus (F1) bullocks were distributed across 14 paddocks of Urocloa brizantha using a completely randomized block design, stratified by initial body weight (BW), at a commercial grass-fed ranch in the northern part of Goias State, Brazil. Each paddock served as an experimental unit, with the number of animals de- pendent on paddock size, initially stocked at a rate of 2 animal units (AU)/ha based on initial BW. The animals were provided with a supplement (25% CP, DM basis) containing flavomicin (25 ppm/kg supplement) offered daily at 0.5% of BW (Control), or supplemented with a blend of tannins (BX, 3,5 g/kg supplement). Individual BW were recorded at processing and shipment, while carcass weight was measured individually at the packing plant. Carcass gain was calculated as the difference between carcass weight and the estimated initial carcass weight, set at 50% of the initial BW, in accordance with customary practices for negotiating feeder cattle in Brazil. Statistical analysis was conducted using Proc Mixed of SAS, with treatment, breed, and treatment*breed considered as fixed effects, and treatment (paddock) as random. Residuals were evaluated for normality, and mean comparisons were conducted using LSMEANS. The results revealed that BX-treated cattle exhibited significant improvements in most performance traits: average daily gain (ADG; 1.181 vs. 0.842 kg/d, P = 0.0027), total BW gain (127.46 vs. 79.13 kg, P = 0.0205), final BW (FBW; 548.74 vs. 517.94 kg, P = 0.0011), hot carcass weight (HCW; 297.21 vs. 277.84 kg, P = 0.0002), and carcass daily gain (0.785 vs. 0.626 kg/d, P = 0.0035; Table). Although no interaction was observed between treatment and breed, Nelore cattle exhibited heavie initial BW (466.29 vs. 392.92 kg, P = 0.0026) compared with F1 cattle. F1 cattle demonstrated superior performance in ADG (1.216 vs. 0.807, P = 0.0008), total gain (141.26 vs. 65.31, P = 0.0015), and carcass daily gain (0.790 vs. 0.621 kg/d, P = 0.0022). In conclusion, supplements containing a blend of tannins and saponins were found to enhance overall performance traits of finished grass-fed cattle, independent of the breed evaluated. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum) in its dehydrated or distillate (garlic oil) form has been used as a feed additive owing to its insecticidal, antimicrobial, and organoleptic properties. Commercial mineral mixtures have been formulated to contain a low proportion of dehydrated garlic powder as a strategy to deter pest flies and increase mineral intake in cattle. As an antimicrobial, garlic powder has the potential to alter the rumen microbiome, with possible implications for feed digestibility and the growth performance of beef cattle. This study evaluated the effect of short-term feeding of a garlic-mineral mixture in feedlot steers receiving high-grain diets. Four groups of twenty steers [total = 80, ~14 mo old, body weight (BW) = 599 ± 32 kg] were randomly assigned to either a 5% garlic-mineral (5DGP) or plain mineral supplement (MS). The individual feed and mineral intakes of the steers were measured with an automatic feeding system. Feed and mineral supplements were tracked in different bunks for each group. Baseline rumen fluid samples were collected from all steers at the end of an acclimatization period before administering the trial supplements. Rumen samples were later collected from 10 steers in each group with the greatest mineral supplement intake over the trial period. Total DNA and RNA were extracted from all rumen samples and subjected to metagenomic and metatranscriptomic sequencing, respectively. None of the bacterial species with an overall relative abundance of greater than 0.1% were differentially abundant between the two supplement treatments, nor did the rumen microbial community structures differ between the two groups (PERMANOVA: R² = 0.02, P = 0.43). Regardless of the dietary supplement, the rumen microbiome of the steers was dominated by uncultured Prevotella spp. (in addition to Prevotella lacticifex) as well as the uncharacterized UBA2810 sp900317945 and UBA2810 sp002351705. Overall, these results show that a 5DGP can be effectively administered to cattle without significantly disrupting the rumen microbiome. [ABSTRACT FROM AUTHOR]

Dairy products have a crucial role in the diets of over 6 billion people worldwide, providing essential nutrients such as energy, high-quality protein, and micronutrients. With dairy cows accounting for nearly 81% of global milk production, strategies to increase milk production sustainably are vital, especially with the U.S. being the second-largest producer. Essential oil blends (EOB), onion peel extract (OPE), and prebiotics such as mannan oligosaccharides (MOS) and galactooligosaccharides (GOS) offer promising avenues to enhance bovine milk production. These additives have the potential to modify rumen ecology and fermentation activity, while also mitigating greenhouse gas emissions in dairy cows. Therefore, this study investigated the effects of combining EOB, OPE, GOS, and/or MOS on specific rumen metabolites and metabolic pathways using the rumen simulation technique (RUSITEC) system. Rumen-cannulated non-lactating Holstein Friesian cows (n = 3) were used as rumen fluid donors. Total mixed ration (TMR) consisted of corn silage (60%), alfalfa hay (20%), and concentrate (20%). Using a completely randomized design, 16 fermentation vessels were divided into 4 groups with 4 replicates each over a 9-d period. The treatments included a control group (CON; TMR only), GEO (TMR+GOS+EOB+OPE), MEO (TMR+MOS+EOB+OPE), and OLEO (TMR+OLG+EOB+OPE). The EOB comprised of garlic, lemongrass, cumin, lavender, and nutmeg (4:2:2:1:1), while OLG contained GOS and MOS in equal proportions. EOB was added at 10 μL/g, and OPE, GOS, MOS, and OLG were included at 30 mg/g TMR. Rumen effluents were collected over 5 d for quantitative untargeted metabolome analysis. Analysis of rumen effluents using liquid chromatography-mass spectrometry and MetaboAnalyst 5.0 revealed 495 detected and identified metabolites. Volcano plot analysis showed no significant differences (P ≥ 0.05) in metabolite abundance between the CON and MEO, GEO, or OLEO treatments. Partial least squares-discriminant analysis (PLS-DA) also indicated no clear separation between the CON and treatment groups, suggesting no significant alteration in the metabolome. Compared with CON, the relative concentrations of dopamine 4-O-glucuronide, proline, and histamine were less while pyrocatechol was greater in MEO group. Isomer 1 of 2-hydroxyhepta-2,4-dienedioic acid, histamine, and dopamine 4-O-glucuronide were less while 2-aminomuconic acid and isomer 1 of hulupinic acid were greater in the GEO group. Histamine was less and hydroxypyridine was greater in the OLEO group. Phosphonate and phosphinate metabolism tended to be upregulated in OLEO. Meanwhile, metabolic pathways related to amino acids, vitamins, nitrogen metabolism, and primary bile acid biosynthesis remained unaltered by MEO, GEO and OLEO treatments. In summary, the study demonstrated that the inclusion of MEO, GEO, and OLEO had no adverse effects on rumen metabolites. Future research should focus on combinations of nutraceuticals that could positively impact nutrient metabolism and production performance of dairy cows. [ABSTRACT FROM AUTHOR]

Mycotoxins, such as deoxynivalenol (DON) produced by Fusarium, are harmful fungal secondary metabolic products that cause economic losses and health risks to humans and livestock. Measures to control and prevent feed contamination with DON are necessary to ensure the safety of livestock. These include strategies based on preventing fungal contamination of feed or limiting contaminants in feed through mycotoxin adsorption and degradation. Soil is a valuable source of diverse microbial communities, potentially harboring DON-degrading bacteria that can be developed into feed additives to mitigate DON. This study aimed to identify microbial consortia from diverse soil samples, that could degrade DON. Soil from central (Lacombe; LA) and southern (Lethbridge; LE) Alberta were used as microbial inoculant. These soils were suspected to host Fusarium spp. which could produce DON in cereal crops growing upon them. The LE samples were further categorized into soil amended with manure (LE-MA) or non-manure (LE-UF). Prior to the study, soil pH and moisture content were measured. After soil collection, field-moist samples were mixed with DON-contaminated wheat (10% wt/wt; d 0) and each soil type was divided into triplicate pots and placed in a controlled environment for 32 d. On d 0, 7, 14 and 32, subsamples were collected from pots, serially diluted in a limited medium containing DON (10 μg/mL) as the only carbon source, and incubated for 2 wk (30°C). The degradation of DON in bacterial cultures was calculated using ELISA. The LA soil was slightly acidic (pH 6.4) compared with LE-MA (7.3) and LE-UF (pH 7.0), while moisture content was greater in LA (18.4%) than LE-MA (14.7%) and LE-UF (13.5%) soils. DONdegrading activity was only detected in LA soil samples and was greatest after 7 d of incubation (21%). We are currently isolating individual bacteria from LA soil for identification and are characterizing the soil microbiota using 16S rRNA sequencing. Overall, this study showed that soil contained bacteria capable of degrading DON, however variation existed depending on soil source. [ABSTRACT FROM AUTHOR]

Pneumonia is the main health issue that farmers have to fight when calves arrive at the rearing farm after marketing and transportation. Calves with pneumonia have a low intake impairing the recovery at arrival. The use of additives to enhance intake and immunity at arrival could be a strategy to minimize those negative effects. A total of 36 calves [body weight (BW) = 71.3 ± 2.83 kg] with pneumonia (ultrasound lung score ≥ 3) arriving at a commercial farm after marketing and transportation were used to evaluate the effect of a mixture of feed additives (FA) comprising a palatability enhancer, standardized olive pomace ex- tract and tributyrin on performance in calves fed 2 L of MR twice daily at 12.5% and ad libitum concentrate feed. Calves were allocated in 4 pens and distributed in 2 treatments (2 pens/treatment); calves fed a concentrate feed without FA since the beginning of the study (arrival to the rearing farm after transport) until weaning (CT; n = 18); calves fed a concentrate feed containing the mixture of FA (CM; n = 18) from arrival until weaning. Calf BW and pen intake were recorded weekly. On d 21 of the study, calves were partially weaned and only milk replacer was offered in the morning, and on d 28 all calves were completely weaned. The study lasted 35 d. Data were analyzed with a mixed-effects model. Final BW of CM calves (95.9 ± 1.29 kg) tended to be greater (P = 0.08) compared with BW of CT calves (92.7 ± 1.29 kg). The CM calves tended (P = 0.06) to have greater ADG than CT calves (0.70 ± 0.037 kg/d and 0.61 ± 0.037 kg/d, respectively). However, a greater sample size may be necessary to observe differences in average concentrate intake measured by pen between treatments (0.82 ± 0.033 kg/d and 0.87 ± 0.033 kg/d for CT and CM, respectively). These results highlight the potential of using a mixture of feed additives with olive pomace extract, palatability enhancers, and tributyrin on the performance recovery of calves with pneumonia on arrival at the rearing farm. [ABSTRACT FROM AUTHOR]

In swine production, using feed antibiotics as antimicrobial growth promotants has been reduced; thus, feed alternatives to manage gut health are required. Dietary fiber and similar carbohydrate structures such as resistant starch, oligosaccharides, and exopolysaccharides are nutritional tools that may enhance gut health in pigs. Dietary fiber may have a role to alleviate diarrheal diseases including in pigs post-weaning but can also reduce constipation in sows, but specific functionality depends on fiber properties. Antibiotics are hypothesized to influence gut health via modulation of intestinal microbial profiles; fermentation and intestinal inflammation are considered important mechanisms. Dietary fiber sources differ in a key functional property: fermentability. Rapid fermentation of fiber and oligosaccharides is associated with changes in microbial profiles and increased metabolite production. Recently, microbial composition was hypothesized to be less important and combined output of metabolites should be the focus. Fiber properties may also manipulate retention time and physico-chemical properties of the undigested residue; hence, nonfermentable fiber may prevent constipation in sows. The fiber-like structure resistant starch is not digested and acts as fermentable fiber but has unique properties, because it specifically increases intestinal abundance of bifidobacteria, which are associated with improved gut health. Using crop breeding, feed processing, and feed additives, the structure of fiber and starch can be altered thereby changing its degradation kinetics and affecting its prebiotic activity. Finally, fiber-like structures such as exopolysaccharides from Limosilactobacillus reuteri and unique oligosaccharides may serve as receptor analogues for pathogenic bacteria, e.g., enterotoxigenic Escherichia coli (ETEC). These receptor analogues block lectin domains of bacterial adhesins and thus prevent adherence of pathogens to the gut wall, thereby avoiding initiation of post-weaning diarrhea. In conclusion, dietary fiber and similar structures possess important functional properties that may also provide important solutions to maintain gut health in pigs. [ABSTRACT FROM AUTHOR]

Two 89-d experiments (Exp 1 and Exp 2) evaluated the effects of feeding an immunomodulatory feed additive (NutraGen; NG) in calves following exposure to bovine viral diarrhea virus (BVDV) on d -3 and Mannheimia haemolytica (MH) infection on d 0. For each experiment, steers [body weight (BW) = 251 ± 38.2 kg)] were randomly allocated to 1 of 3 treatments. Treatments included a placebo (CON; Exp 1 n = 5; Exp 2 n = 5), a placebo fed from d -18 to d -3 followed by NG fed from d -3 to d 28 (CHLG; Exp 1 n = 5; Exp 2 n = 6), and NG fed from d -18 to d 28 (PREC; Exp 1 n = 6; Exp 2 n = 5). Data were analyzed using the GLIMMIX procedure of SAS Version 9.4 (SAS Institute, Cary, N.C.). Animal served as the experimental unit and time served as a repeated measure. Treatment, time, and the treatment × time interaction served as fixed effects. Block was included as a random effect. Multiple treatment × time interactions and time effects occurred for serum glucose, lactate, blood urea nitrogen, and non-esterified fatty acid concentrations (P ≤ 0.003) in both experiments. There was a general trend for serum glucose to decrease over time postchallenge, suggesting increased cellular utilization of glucose in response to the challenge. In Exp 1, treatment effects occurred for serum glucose (P ≤ 0.001) and serum lactate (P ≤ 0.01), where calves assigned to the CHLG treatment displayed the greatest concentrations of the metabolites. Blood urea nitrogen concentrations peaked at h 48 in Exp 1 and h 6 in Exp 2. There were no treatment effects or treatment × time interactions for serum cortisol, hair cortisol, or fecal corticosterone concentrations in either experiment (P ≥ 0.17). There were, however, multiple time effects for serum cortisol, hair cortisol, and fecal corticosterone concentrations in both experiments (P ≤ 0.02), indicating that the challenge directly impacted cortisol and corticosterone production. Serum cortisol steadily increased from h 96 to h 168 in both experiments. Trends in cortisol and corticosterone production were similar in both experiments; however, peak concentration times for these variables occurred later in Exp 2. These data suggest that feeding NG to calves may alter glucose availability and nutrient utilization in response to infection resulting from a bovine respiratory disease challenge. [ABSTRACT FROM AUTHOR]

Two 89-d experiments (Exp 1 and Exp 2) evaluated the effects of feeding an immunomodulatory feed additive (NutraGen; NG) in calves following exposure to bovine viral diarrhea virus (BVDV) on d -3 and Mannheimia haemolytica (MH) infection on d 0. For each experiment, steers [body weight (BW = 251 ± 38.2 kg were randomly allocated to 1 of 3 treatments. Treatments included a placebo (CON; Exp 1 n = 5; Exp 2 n = 5), a placebo fed from d -18 to d -3 followed by NG fed from d -3 to d 28 (CHLG; Exp 1 n = 5; Exp 2 n = 6), and NG fed from d -18 to d 28 (PREC; Exp 1 n = 6; Exp 2 n = 5). Data were analyzed using the GLIMMIX procedure of SAS Version 9.4 (SAS Institute, Cary, N.C.). Animal served as the experimental unit and time served as a repeated measure. Treatment, time, and the treatment × time interaction served as fixed effects. Block was included as a random effect. Cytokine data were tested for normality using the Shapiro-Wilk test, determined to be non-normal, and logarithm (base 10) transformed as a result prior to statistical analysis. Multiple time effects and treatment × time interactions occurred for serum MH, BVDV 1, and BVDV 2 antibody concentrations in both experiments (P ≤ 0.05). In Exp 1, there was a tendency for an overall treatment effect for calves assigned to the CON treatment to exhibit the greatest MH serum antibody concentrations (P = 0.06). While no differences were detected between treatment groups, BVDV 1 and BVDV 2 antibody concentrations peaked on the same day in both experiments, d 28 post-challenge. There were no treatment × time interactions, treatment effects, or time effects for serum TNF-α, IFN-γ, or IL-17A concentrations (P ≥ 0.13) in either experiment. In Exp 1, there was a treatment effect for serum IL-10 (P ≤ 0.0001), where calves assigned to the PREC treatment had increased serum IL-10 concentrations when compared with calves in the other treatment groups. In Exp 2, there was a tendency for a treatment effect for IL-10 concentrations, where calves assigned to the PREC treatment displayed decreased IL-10 concentrations when compared with calves in the other treatment groups (P = 0.07). These data suggest that feeding NG to calves prior to a stress experience may alter cellular responses. Overall, these experiments suggest that NG impacted antibody concentrations and cytokine expression during a bovine respiratory disease challenge. [ABSTRACT FROM AUTHOR]

Aims: The objective of this study is to identify and investigate the antifungal and antioxidant potential of lactic acid bacteria (LAB) isolated from traditional fermented products. Methods and results: In this work, a collection of LAB was isolated from traditional fermented products collected in four Tunisian regions. After first screening using the overlay method, seven bacterial strains were retained due to their high antifungal effect. Four strains of Limosilactobacillus fermentum were identified, one strain of Lacticaseibacillus paracasei, one strain of Lacticaseibacillus rhamnosus and one strain of Enterococcus faecium. The antifungal and the antioxidant potential of these bacteria were then evaluated. Bacterial strains were effective against six fungal strains with minimum inhibitory concentrations ranging from 25 to 100 mg/ml and minimum fungicidal concentrations ranging from 50 to 200 mg/ml. Cell‐free supernatants of LAB were analysed by HPLC‐DAD and LC–MS‐qTOF‐MS analysis. Results showed significant production of organic acids as well as several phenolic compounds. Correlation analysis confirmed that PLA and 1,2‐dihydroxybenzene were positively correlated with antifungal potential. The results of the antioxidant activity highlighted an ABTS radical cation scavenging activity ranging from 49% to 57% and a DPPH trapping percentage ranging from 80% to 97%. Conclusions: Therefore, due to these characteristics, identified lactic acid bacteria strains have shown their effectiveness to perform as antifungal and antioxidant agents. Significance and impact of the study: Since microbial contamination is at the root of extensive losses in the food sector, the identified strains or their metabolites can potentially be used as additives to limit micro‐organism spoilage in food products and increase their shelf life. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effects of bacteria (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus lichenformis, Bacillus subtilis, and Enterococcus faecium), enzymes (amylase, hemicellulose, and xylanase), and yeast as additives on the ruminal microbiome. We hypothesized that inclusion of bacteria, enzymes, and yeast would impact butyric bacterial populations. Eight fermenters were arranged in a duplicated 4 × 4 Latin square with the following treatments: 1) control without additives (CTRL); 2) bacterial culture and enzyme blend (EB); 3) bacterial culture and enzyme blend with a live yeast and yeast culture blend (EBY); and 4) double dose of bacterial culture and enzyme blend and the yeast products blend (2X). We conducted four fermentation periods of 10 d each, with the last 3 d for collection of samples. Overall, 64 solid and liquid samples were analyzed by amplification of the V4 region of bacterial 16S rRNA. Data were analyzed with R and SAS. The following orthogonal contrasts were used: 1) ADD—the control compared to all treatments with additives (CTRL vs. EB, EBY, and 2X); 2) YEAST—treatment without yeast compared to those with yeast (EB vs. EBY and 2X); and 3) DOSE—the single dose of enzymes, bacteria, and yeast compared to the doubled dose (EBY vs. 2X). Family Prevotellaceae was more abundant when additives were added (ADD). Additives (ADD) also increased relative abundance of Prevotellaceae Ga6A1 and YAB2003 in solid fraction, and of Prevotellaceae Ga6A1 and two members of Lachnospiracea family in liquid fraction. Yeast (YEAST) decreased relative abundance of Succinivibrionaceae UCG-001 and increased abundance of Ruminococcus and Prevotellaceae UCG-003 in solid fraction. Doubling the dose of enzymes and microbial additives (DOSE) decreased the abundance of Succiniclasticum in solid fraction and Selenomonadaceae in the liquid. Molar proportion of butyrate was highly correlated with abundance of Prevotellaceae Ga6A1 in solid (r = 0.68) and liquid fraction (r = 0.79), and with Unclassified Lachnospiraceae in liquid (r = 0.70). Our results demonstrate that YEAST decreases abundance of succinate synthesizing bacteria, while DOSE decreases abundance of bacteria that metabolize succinate into propionate. Combined bacteria, enzymes, and yeast increase the relative abundance of specific genera primarily within the Prevotellaceae family, which may explain the increase in butyrate molar proportion observed with ADD. [ABSTRACT FROM AUTHOR]

Plant secondary metabolites (PSM) such as condensed tannins, hydrolysable tannins, saponins and essential oils purportedly impact rumen fermentation at low inclusion rates in beef cattle diets. Twelve steers (347 ± 23 kg BW) of British and continental influence were allocated to 1 of 4 replicated 3 x 3 Latin squares. Latin squares each had 14 d periods (10 d adaptation and 4 d for sample collection). All cattle were fed ground warm-season hay (89.5% DM, 92.8% OM, 65.9% NDF, 43.6% ADF, 6.70% CP) at 1.5% of BW (DM-basis) and supplemented with soybean meal at 0.18% of BW (DM-basis) once daily. Treatments consisted of a blend of tannins, saponins and essential oils provided at 0% (Control), 0.1% (Low) and 0.3% (High) of hay offering. Treatments were mixed with daily soybean meal allotment and provided before feeding of hay. Urine and feces were completely collected from d 11 through 14 at 0730 h and daily amounts of urine and feces produced were measured gravimetrically. Measures of gaseous exchange were determined via indirect calorimetry on d 13 and 14. Open-circuit respiration calorimeters (91.4 x 91.4 x 191.2 cm) were used to collect respired gas and ruminal methane production. Total oxygen consumption and production of carbon dioxide and methane were calculated from the difference in concentration of oxygen, carbon dioxide, and methane from air exhausted from each calorimeter and concentration of oxygen, carbon dioxide, and methane in ambient air and multiplied by amounts of air flowing from each calorimeter standardized for temperature, pressure, and humidity. Data were analyzed for a Latin square using the MIXED procedure of SAS with fixed effect of treatment, period and square and random effect of steer. Linear and quadratic contrast coefficients were assigned using PROC IML for uneven spacing of treatments. Significance was declared when P ≤ 0.05. Per experimental design, forage N and OM intake did not differ (P ≥ 0.77). Apparent total tract digestion of OM, NDF and ADF did not differ (P ≥ 0.66) among treatments. Fecal nitrogen excretion, and the percentage of N excreted in feces increased linearly (P = 0.01). N balance tended (P = 0.08) to decrease linearly with increasing PSM supplemented. Methane (L/kg DMI) was not affected (P = 0.28) by treatments. Methane, GE, DE, and ME (mcal/kg DMI) was unaffected (P = 0.19) by treatment. Under the conditions of this experiment, a blend of PSM had little effect on rumen fermentation or energy metabolism in beef steers. [ABSTRACT FROM AUTHOR]

A total of 80 crossbred, high-risk heifers (initially 250 ± 4.2 kg BW), were transported from an Oklahoma City, Oklahoma sale barn to the Kansas State University Beef Cattle Research Center. Cattle were unloaded and randomly placed into one of four receiving pens and provided ad libitum hay and water. Each pen was randomly assigned to one of the four rest times before processing: (1) immediately upon arrival (0); (2) after a 6-h rest period (6); (3) after a 24-h rest period (24); and (4) after a 48-h rest period (48). After all cattle were processed, heifers were allotted into individual pens with ad libitum access to a receiving ration and water. Heifers were weighed individually on d 0, 7, 14, 21, 28, and 35 to calculate average daily gain (ADG). Feed added and refusals were measured daily to determine dry matter intake (DMI). A fecal egg count reduction test and analysis of blood serum metabolites were also conducted. All data were analyzed using the GLIMMIX procedure of SAS (v. 9.4, Cary, NC) with individual animal as the experimental unit. Processing time did not impact (P > 0.05) heifer BW or ADG. From d 0 to 35, DMI decreased linearly (P = 0.027) as rest time increased. The number of days for heifers to reach a DMI of 2.5% BW was linearly increased (P = 0.023) as rest time increased. There was no evidence of differences (P ≥ 0.703) among rest times for feed efficiency. While morbidity did not differ between treatments (P > 0.10), mortality increased linearly (P = 0.026) as the time of rest increased. A significant processing time × day interaction (P < 0.0001) was observed for the prevalence of fecal parasites, where the percentage of positive samples was significantly lower 14-d after anthelmintic treatment, regardless of the processing time. Serum IBR titer for heifers processed at either 0 or 6-h upon arrival was significantly higher (P < 0.01) on d 35 compared to d 0. Heifers processed after a 48-h rest period had significantly higher glucose values (P < 0.01) on d 0 compared to heifers processed at 0, 6, or 24-h. In summary, rest time prior to processing did not impact receiving calf growth performance. A 6-h rest period upon arrival appeared to be most beneficial to DMI. Anthelmintic treatment at processing reduced the parasitic load in heifers processed at all times. Vaccine titer did not increase after initial processing in heifers processed 24- or 48-h after arrival, indicating the seroconversion of IBR antibodies during the longer rest period. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of supplementing a commercial porous ceramic clay particle, with or without a blend of preservatives, on the performance and nutrient digestibility of weanling pigs. Fifteen weanling pigs of the Yorkshire, Landrace, and Duroc breeds were blocked by breed and randomly assigned to one of three treatments (n = 5): (1) Control, non-medicated diet with no additional feed additives (CON); (2) PowerGuard, basal diet with 0.25% of the DM consisting of a ceramic particle mixed into the pelleted feed (PG; MB Nutritional Sciences, Lubbock, TX, 79403); or (3) Power Guard + a blend of preservatives, basal diet with 0.3% of the DM consisting of the ceramic clay and preservatives mixed into the pelleted feed (PG-D). The facility was temperature controlled with an average temperature of 28.5 °C. Pigs were offered ad libitum access to feed and water and were housed individually in elevated crates. Body weights were collected upon enrollment on day 0 and at the end of the observation period on day 18. On day 15 , a 72-h total feed and fecal collection period began. Feed and fecal samples were analyzed for DM, CP, Ash, OM, ADF, NDF, zinc, copper, thiamin (vitamin B1), and retinol (vitamin A). Liver samples were collected immediately after harvest and frozen for later mineral analysis. Data were analyzed using Proc Mixed in SAS with dietary group as the main effect and block as the random effect (SAS 9.4, Cary, NC). There were no treatment differences in performance measures including final BW, ADG, or G:F (P ≥ 0.701). There were no treatment differences in diet nutrient digestibility for DM, CP, Ash, OM, ADF, or NDF (P ≥ 0.312). Additionally, there were no treatment effects on zinc, copper, or retinol digestibility (P ≥.298); however, thiamin inclusion rate was increased for the PG-D treatment, thus leading to an increased digestibility for thiamin (P = 0.018) in the PG-D treatment. There were no treatment differences in hepatic mineral concentrations (P ≥ 0.532); however, there was a tendency for pigs fed PG-D to have increased hepatic concentrations of lead and mercury when compared with both PG and CON pigs (P ≤ 0.066). In summary, supplementation of a commercial ceramic particle with or without a blend of preservatives to weaned pigs did not affect performance or apparent nutrient digestibility. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of using conventional productivity-enhancing technologies (PETs) with or without other natural PETs on the growth performance, carcass traits, and environmental impacts of feedlot cattle. A total of 768 cross-bred yearling steers (499 ± 28.6 kg; n  = 384) and heifers (390 ± 34.9 kg; n  = 384) were offered a barley grain-based basal diet and divided into implanted or non-implanted groups. Steers were then allocated to diets that contained either: (i) no additive (control); natural feed additives including (ii) fibrolytic enzymes (Enz), (iii) essential oil (Oleo), (iv) direct-fed microbial (DFM), (v) DFM + Enz + Oleo combination; conventional feed additives including (vi) Conv (monensin, tylosin, and beta-adrenergic agonists [βAA]); or Conv with natural feed additives including (vii) Conv + DFM + Enz; (viii) Conv + DFM + Enz + Oleo. Heifers received one of the first three dietary treatments or the following: (iv) probiotic (Citr); (v) Oleo + Citr; (vi) Melengesterol acetate (MGA) + Oleo + βAA; (vii) Conv (monensin, tylosin, βAA, and MGA); or (viii) Conv + Oleo (ConvOleo). Data were used to estimate greenhouse gas (GHG) and ammonia (NH3) emissions, as well as land and water use. Implant and Conv-treated cattle exhibited improvements in growth and carcass traits as compared to the other treatments (P  < 0.05). Improvements in the performance of Conv-cattle illustrated that replacing conventional feed additives with natural feed additives would increase both the land and water required to satisfy the feed demand of steers and heifers by 7.9% and 10.5%, respectively. Further, GHG emission intensity for steers and heifers increased by 5.8% and 6.7%, and NH3 emission intensity by 4.3% and 6.7%, respectively. Eliminating the use of implants in cattle increased both land and water use by 14.6% and 19.5%, GHG emission intensity by 10.5% and 15.8%, and NH3 emission intensity by 3.4% and 11.0% for heifers and steers, respectively. These results demonstrate that the use of conventional PETs increases animal performance while reducing the environmental impacts of beef production. Restricting use would increase the environmental footprint of beef produced for both domestic and international markets. [ABSTRACT FROM AUTHOR]

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage. [ABSTRACT FROM AUTHOR]

One hundred and forty-four Angus × Simmental steers were allotted by body weight (BW ; 363 kg), breed composition, and farm origin to a 3 × 2 factorial arrangement of six treatments (4 pens per treatment) to determine the effect of Mootral (garlic + citrus extract; 0.25% of the diet dry matter [ DM ] vs. 0.0%) on methane (CH 4 ) emissions, growth, and carcass characteristics of feedlot cattle. During the first 84 d, cattle were fed three different forage concentrations in the diet (15%, 41.5%, or 68% corn silage) with or without Mootral. From day 85 to slaughter, corn silage was included at 15% of the diet DM with or without Mootral. CH4 emissions were measured on day 42 to 46 and day 203 to 207. Data were analyzed using the GLIMMIX procedure of SAS. Mootral did not affect CH4 emissions on days 42 to 46 (P ≥ 0.47), but there was a forage effect, where steers fed the 68% corn silage emitted more CH4 on a g/d (P = 0.05) and a g/kg of dry matter intake (DMI ; P = 0.007) basis and tended (P = 0.07) to produce more CH4 on g/kg BW basis compared to steers fed the 15% corn silage diet. On day 203 to 207, steers fed Mootral emitted less (P ≤ 0.03) CH4 on a g/d, g/kg DMI, and g/kg BW basis compared to steers not fed Mootral. There was an interaction (P = 0.03) between forage concentration and Mootral for DMI from day 0 to 84, where Mootral decreased DMI of steers fed 15% corn silage but did not affect DMI of steers fed 41.5% or 68% corn silage. There were no effects (P ≥ 0.22) of forage concentration or Mootral on BW or average daily gain at any time, or on DMI from day 84 to slaughter and overall. However, overall calculated net energy for maintenance (NE m ) and net energy for gain (NE g ) tended to be greater for steers fed Mootral (P ≤ 0.10). Intake from day 0 to 84 was lower and gain:feed from day 0 to 84 and overall was greater (P = 0.04) for steers fed 68% compared to steers fed 41.5% corn silage. Calculated NEm and NEg from day 0 to 84 and overall were greater for steers fed 68% corn silage compared to steers fed 41.5% corn silage (P ≤ 0.03). Mootral tended to decrease (P ≤ 0.09) fat thickness and yield grade. In conclusion, increasing forage concentration increased CH4 emissions and Mootral decreased CH4 production in 15% corn silage diets and tended to improve carcass leanness. [ABSTRACT FROM AUTHOR]

Three hundred twenty newly weaned pigs (21 days of age; 6.7 ± 0.3 kg BW) were used to determine the effects of supplementing low-complexity (LC) deoxynivalenol- (DON) contaminated nursery diets with a feed additive or fish oil on growth performance and immune response to an Escherichia coli lipopolysaccharide (LPS) challenge. Pens were randomly assigned to 1 of 5 dietary treatments (n = 8 pens per treatment): positive control (PC ; contained multiple animal protein sources), or 1 of 4 LC diets (contained only plant-based protein sources) without (NC ; negative control) or with ~ 3.5 ppm DON contamination, without (DON‐) or with a feed additive containing a blend of immune-modulating components (DON+ ; 2 mg/kg, as-fed) or fish oil (DONω3 ; 2.5%, as-fed). Dietary treatments were fed during phases I and II (7 and 15 days, respectively) and a common phase III diet was fed for 20 days. On day 22, two pigs per pen were injected IM with 30 μg/kg BW LPS and 1 pig per pen with 1 mL saline. Rectal temperatures were recorded at 0, 1, 2, 3 h after injection. At 3 h, blood was collected for plasma cytokine analysis and small intestinal histomorphology was assessed. In phase I, pigs fed PC and NC did not differ for ADG, ADFI and G:F, but these outcomes were greater than for pigs fed DON+ and DONω (P < 0.05). In phase II, pigs fed NC had greater ADG and PC had greater ADFI but lower G:F than pigs fed DON‐ and DONω3 (P < 0.05). At the end of phase II, pigs fed DONω3 tended to have lower BW than PC and NC (P = 0.084 and 0.079, respectively). In phase III and overall, there were no differences among dietary treatments for ADG, ADFI, G:F, or final BW. The LPS injection increased rectal temperature and reduced jejunal and ileal villus height (versus saline; P < 0.05). Plasma interferon-γ concentration was only increased by LPS for pigs fed PC, NC, and DON+ compared to the saline-injected counterparts (P < 0.05). Regardless of LPS injection, jejunal villus height was greater for pigs fed DON+ than DONω3 (P < 0.05) and ileal villus height was greater for pigs fed DON+ and PC than DONω3 (P < 0.05). Therefore, nursery diet complexity did not affect growth performance or immune response to LPS. Regardless of DON contamination and feed additive inclusion in phases I and II, pigs were able to achieve nursery exit BW not different from those fed PC. The feed additive offered marginal benefits for small intestinal villus height and immune response for pigs fed DON-contaminated LC nursery diets. [ABSTRACT FROM AUTHOR]

This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis , Fusobacterium necrophorum , and lipopolysaccharides (40%, 35%, and 25% of the preparation, respectively) on ruminal fermentation [pH, ammonia-N (NH3-N), lactate, and volatile fatty acids (VFA)] of beef steers during a 21-d step-up diet adaptation. Eight ruminally cannulated Angus crossbred beef steers (658 ± 79 kg of body weight) were assigned in a crossover design to be transitioned from a diet containing ad libitum bermudagrass hay [ Cynodon dactylon (L.) Pers.] plus 0.45 kg/d (as fed) of molasses with 0 (CON) or 3 g of PAP (PAP) to a high-grain diet. Transition consisted of three 7-d steps of increased inclusion of cracked corn (35%, 60%, and 82% of the diet DM for STEP1, STEP2, and STEP3, respectively). On each transition day and 7 d after STEP3 (STEP3-7d), ruminal fluid samples were obtained every 3 h for 24 h. Feeding 3 g of PAP daily increased (P < 0.01) average ruminal pH during STEP3 compared with CON steers (5.6 vs. 5.4 ± 0.05, respectively). During STEP1, NH3-N concentration was greater (P < 0.01; 9.4 vs. 6.8 ± 0.74 mM, respectively), and time (min/d) and area (time × pH) of ruminal pH below or equal to 5.2 was lesser (P ≤ 0.03) for steers consuming PAP compared with steers assigned to CON treatment (33.4 vs. 73.3 ± 21.7 min/d and 187.4 vs. 406.3 ± 119.7 min × pH/d, respectively). Steers consuming PAP had greater acetate:propionate ratio at 0, 3, and 6 h relative to diet change compared with CON (2.42, 2.35, 2.29 vs. 1.66, 1.79, and 1.72 ± 0.17, respectively), whereas butyrate molar proportions increased (P = 0.02; 17.1 vs. 11 ± 1.58 mol/100 mol for CON and PAP, respectively) when PAP was not fed at STEP2. Total ruminal lactate concentrations were not affected by PAP feeding (P > 0.11). In conclusion, feeding 3 g/d of polyclonal antibody preparation against S. bovis, F. necrophorum , and lipopolysaccharides was effective in increasing ruminal pH, A:P ratio, and NH3-N concentrations, possibly attenuating the risks of ruminal acidosis in steers during the step-up transition from forage to high-grain diets. [ABSTRACT FROM AUTHOR]

We examined the effects of dietary supplementation of a multicomponent blend of prebiotics and probiotics on health, immune status, metabolism, and performance of newly weaned beef steers during a 35-d receiving period. Eighty newly weaned crossbred steers (12-hour postweaning; 206 ± 12 kg of body weight [BW]) from a single source were stratified by BW into four pens (20 steers per pen) such that each pen had similar BW at the beginning of the experiment. The pens were randomly assigned to receive a corn silage-based diet with no additive (CON; two pens; n = 40 steers) or a basal diet supplemented with SYNB feed additive at an average of 28 g/steer/d (SYNB; two pens; n = 40 steers). The SYNB additive is a blend of live Saccharomyces cerevisiae and the fermentation products of S. cerevisiae , Enterococcus lactis , Bacillus licheniformis , and Bacillus subtilis and was supplemented for the first 21 d only. Percentage of steers treated for bovine respiratory disease (BRD) was calculated for each dietary treatment. Daily dry matter intake (DMI) and meal events (meal frequency and duration) were measured. Weekly BWs were measured to calculate average daily gain (ADG). Blood samples collected on days 0, 14, 21, 28, and 35 were used for ex-vivo tumor necrosis factor alpha (TNF-α) release assay following lipopolysaccharides (LPS) stimulation, plasma metabolome analysis, and mRNA expression analysis of 84 innate and adaptive immune-related genes. Compared with CON, supplemental SYNB increased (P ≤ 0.05) ADG, DMI, and meal events during the first 7 d. At d 21, there was no treatment effect (P > 0.05) on final BW, DMI, ADG, and meal events; however, beef steers fed supplemental SYNB had greater (P = 0.02) meal duration. Over the entire 35-d receiving period, beef steers fed supplemental SYNB had greater (P = 0.01) ADG and feed efficiency, tended to have greater (P = 0.08) meal duration, and had lower percentage (35 vs. 50%) of animals treated for BRD and lower percentage of sick animals treated for BRD more than once (7.15 vs. 45%). Whole blood expression of pro-inflammatory genes was downregulated while that of anti-inflammatory genes was upregulated in beef steers fed supplemental SYNB. Beef steers fed supplemental SYNB had lower (P = 0.03) plasma concentration of TNF-α after LPS stimulation. Six nutrient metabolic pathways associated with health benefits were enriched (false discovery rate ≤ 0.05) in beef steers fed supplemental SYNB. This study demonstrated that dietary supplementation of SYNB during the first 21 d of arrival reduced BRD morbidity, improved the performance, immune, and metabolic status of beef steers over a 35-d receiving period thereby extending the SYNB effect by a further 14 days post supplementation. [ABSTRACT FROM AUTHOR]

Mitigation of enteric methane (CH4) presents a feasible approach to curbing agriculture's contribution to climate change. One intervention for reduction is dietary reformulation, which manipulates the composition of feedstuffs in ruminant diets to redirect fermentation processes toward low CH4 emissions. Examples include reducing the relative proportion of forages to concentrates, determining the rate of digestibility and passage rate from the rumen, and dietary lipid inclusion. Feed additives present another intervention for CH4 abatement and are classified based on their mode of action. Through inhibition of key enzymes, 3-nitrooxypropanol (3-NOP) and halogenated compounds directly target the methanogenesis pathway. Rumen environment modifiers, including nitrates, essential oils, and tannins, act on the conditions that affect methanogens and remove the accessibility of fermentation products needed for CH4 formation. Low CH4-emitting animals can also be directly or indirectly selected through breeding interventions, and genome-wide association studies are expected to provide efficient selection decisions. Overall, dietary reformulation and feed additive inclusion provide immediate and reversible effects, while selective breeding produces lasting, cumulative CH4 emission reductions. [ABSTRACT FROM AUTHOR]

Aims: The rise in antibiotic resistance requires the reduction of antibiotic use in all sectors. In animal production, many commercial alternatives to antibiotics have been developed for incorporation into feeds, but a lack of evidence on their antibacterial activity limits confidence in their application. We aim to compare the antibacterial activity of feed additives and active ingredients to better understand their usefulness. Methods and Results: The antibacterial activity of 34 active ingredients and feed additives, including medium‐ and short‐chain organic acids and essential oils, was tested against pure cultures of five bacterial swine pathogens. Antibacterial activity was observed using an agar plug diffusion method and quantified via broth microdilution. A diverse range of antibacterial activities were observed. The highest inhibitory activity against Staphylococcus aureus and Streptococcus suis was exhibited by the C12 monoglyceride (0.49 mg ml−1). The monoglyceride of C12 was more effective than C12:0 against Strep. suis, but neither C12:0 nor its monoglyceride showed efficacy against the gram‐negative micro‐organisms tested. The most active against Escherichia coli were the C6:0 medium‐chain organic acids and potassium diformate (1.95 mg ml−1). For Salmonella Typhimurium, potassium diformate, sodium diformate, and a blend of C8:0/C10:0 (each 1.96 mg ml−1), and for Actinobacillus pleuropneumoniae, eugenol (0.49 mg ml−1) showed the most promising activity. Conclusions: We identified broad‐spectrum antibacterial activity, such as the C6:0 MCOA, and those with interesting narrow‐spectrum activity, notably the killing of Strep. suis by C12 monoglyceride. We have identified additives that show the most promising bioactivity against specific pathogens. Significance and Impact of the study: We broadly compare a large collection of feed additives and active ingredients for their antibacterial activity against a diverse panel of bacterial swine pathogens. This provides a solid base of evidence which can drive the development of feed supplementation strategies with the aim of reducing dependency on antibiotic use in swine production. [ABSTRACT FROM AUTHOR]