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A study was conducted to evaluate the efficiency of guanidinoacetic acid (GAA) in diets containing varying levels of corn replacement with low-tannin sorghum (LTS) for laying hens in the later stage of production. In a 12-wk study, a total of 288 laying hens at 52 wk of age were divided into 6 treatment groups. Each treatment group had 8 replicates, each of which consisted of 6 hens. A 2 × 3 factorial design was used to investigate the impact of substituting corn with LTS at 3 levels (100% corn, 50% LTS, and 100% LTS) with 2 doses of GAA supplementation (0 and 0.6 g/kg). The results indicate that there were interaction effects (P< 0.05) between diet type and GAA supplementation on protein digestibility and AMEn, with the GAA supplement being more effective in the 100% LTS group. Replacing corn with LTS at both levels had no negative effects on performance and metabolic profile. In contrast, the 100% LTS diet increased monounsaturated fatty acids in the yolk (P< 0.05), but decreased the yolk color index, the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) in the yolk, ileal digestibility of energy, and AMEn when compared to the 100% corn diet (P< 0.05). Regardless of the diet, dietary supplementation with GAA resulted in increases (P< 0.05) in shell-breaking strength, the PUFA to SFA ratio in egg yolk, and concentrations of creatine and nitric oxide in serum. There was also a decrease (P< 0.05) in serum malondialdehyde concentration with GAA supplementation. In conclusion, the positive effects of GAA on protein digestibility and AMEn were found to be more pronounced when corn was completely replaced with LTS. However, the positive effects of GAA on egg-laying performance, eggshell quality, antioxidant status, and yolk fatty acid composition remained consistent regardless of the extent to which corn was substituted with LTS.

The present study evaluated the effects of butyric acid supplementation and Saccharomyces boulardii(alone or in combination) on growth performance, nutrient digestibility, bone mineralization, and blood hormones of male broiler chickens fed a diet including reduced levels of nonphytate phosphorus (NPP). The chickens were allocated to 6 dietary treatments: 1) positive control diet with adequate amounts of NPP (PC; 0.48, 0.43, and 0.39% in the starter, grower, and finisher period, respectively); 2) negative control diet with low amounts of NPP (NC; 0.38, 0.33, and 0.29% in the starter, grower, and finisher period, respectively); 3) NC plus 500 FTU/kg microbial phytase (PHY); 4) NC plus 0.2% butyric acid (BA); 5) NC plus 1 × 108 cfu/kg S. boulardii(SB); 6) NC plus butyric acid and S. boulardii(BA+SB). Each treatment had 5 pen replicates of 25 birds. After 6 wk, the body weight and ADG in birds fed with any of the diets were higher (P < 0.001) than those in birds fed with the NC diet, where the birds fed with the PHY and BA+SB diets had the highest values. However, only the PHY diet improved (P = 0.041) overall F:G. All diets, except the SB diet, resulted in the increased apparent ileal digestibility coefficient (AIDC) of CP, AMEn, and tibia ash content and decreased serum alkaline phosphatase level compared with the NC diet (P < 0.05). Broiler chickens fed with the PHY, SB, and BA+SB diets also had increased AIDC of phosphorus (P = 0.017) than those fed with the NC and PC diets. Feeding PC, PHY, and BA+SB diets increased (P = 0.007) the tibia phosphorus content but decreased (P = 0.033) serum parathyroid hormone concentration. Overall, the present data indicate that the simultaneous inclusion of butyric acid plus S. boulardiiin the low-NPP diets was beneficial for improving growth rate and bone mineralization, but not for feed efficiency.

An experiment was conducted to study the effect of water supplementation of organic acid-chelated trace minerals (OTM) on production traits, carcass characteristics, intestinal histomorphology, and nutrient digestibility in African ostrich chicks from 8 to 12 mo of age. A total of 20 growing ostriches, with almost similar body weight (73.4 to 75.8 kg), were individually distributed in outdoor paddocks of ≈ 24 m2and were randomly allocated into 1 of the following 4 treatments: (1) control/basal diet, (2) low OTM (basal diet + 100 mg/bird/day OTM powder in water), (3) medium OTM (basal diet + 1 g/bird/day OTM powder in water), and (4) high OTM (basal diet + 2 g/bird/day OTM powder in water). The body weight gain and feed conversion efficiency were greater (P< 0.05) in ostriches receiving medium-OTM treatment compared to control during the overall phase of the experiment. Although whole carcass yield, the yield of parts, and the relative weights of internal organs were not affected by experimental treatments, supplementation of higher amounts of OTM (medium- and high-OTM) resulted in a decrease (P< 0.05) in the subcutaneous and abdominal fat contents. Medium- and high-OTM treatments increased (P< 0.05) the villus height/crypt depth ratio in the jejunum and ileum compared with control and low-OTM treatments. Moreover, ostriches receiving the medium-OTM had also higher total tract apparent digestibility of energy (P= 0.048), ether extract (P= 0.050), crude fiber (P= 0.063), and higher AMEn(P= 0.094) than the control group. Overall, supplementation of OTM at the level of 1 g/bird/day to the drinking water of growing ostriches fed diets containing the recommended levels of inorganic trace minerals could beneficially affect productive performance, nutrient digestibility, and intestinal morphology.

The current study was aimed at elucidating the effects of methionine source and L-carnitine (CT) on performance, immunity, stress indicators, and antioxidant status in broilers kept under chronic heat stress (HS). A total of 720 one-day-old (Ross 308) male broiler chickens were assigned to 5 dietary treatments with 6 replicates and 24 chickens per replicate. The 4 HS treatments included 2 sources of methionine (DL-methionine vs. the DL-methionine-hydroxy analogue [MHA]) and 2 levels of CT supplementation (0 and 200 mg CT/kg of diet). A thermoneutral group containing DL-methionine supplement but without CT supplement was considered the experimental control group (TN-CON). The HS groups were kept in a cyclic HS environment at 33°C to 34°C for 8 h (10:00–18:00) per day beginning on d 3. Dietary supplementation with either CT or MHA significantly reversed the HS-induced decreases in uniformity rate and European performance index, as well as the HS-induced increase in the heterophile to lymphocyte ratio. The relative weight of the thymus and bursa, the total antibody titer against various antigens for both primary and secondary responses, the total antioxidant capacity (TAC), glutathione peroxidase activity, concentrations of insulin-like growth factor 1 and malondialdehyde (MDA), and HSP70 expression in the liver and hypothalamus all improved when MHA was substituted for DL-methionine in the diet. Broilers in CT-supplemented groups had lower relative liver weight, fat content in the abdomen, breast, and thigh, plasma MDA and corticosterone concentrations, but higher relative thymus weight, plasma TAC levels, and catalase activity. Broilers fed diets containing both MHA and CT had growth rates, feed:gain ratios, and mortality rates similar to the TN-CON group, despite the lack of interaction effects between methionine source and CT supplementation on any measured parameters. Overall, adding either CT or MHA to the diet of broiler chickens raised in HS conditions improved their antioxidant status, but MHA had a more pronounced effect on enhancing growth performance and stress indicators.

The effects of emulsifier blend (EB) supplementation of diets with various levels of metabolizable energy (ME) and crude protein (CP) on broiler performance, digestibility, gut morphology, and muscle fatty acid profile were investigated over a 42-d period. Diets were arranged factorially (2 × 2 × 3) and consisted of 2 levels of ME (normal [commercially recommended levels] and low [100 kcal/kg reduction in dietary ME]), 2 levels of CP and limiting amino acids (normal [commercially recommended levels] and low [95% of the normal CP level]), and 3 levels of EB supplementation (0, 1, and 2 g/kg of diet). A total of 1,200 one-day-old male broiler chickens (Ross 308) were randomly assigned to 12 treatment groups (5 pens/treatment with 20 birds/pen). Supplemental EB linearly improved (P< 0.05) final body weight, overall average daily gain, and feed conversion ratio, but the magnitude of the responses was greater in low-ME and low-CP treatments, resulting in significant ME × CP × EB interactions. Similarly, the inclusion of EB in the diet, particularly at 2 g/kg, increased the ileal digestibility of crude protein and crude fat, as well as the AMEn value (P< 0.05), but the response was greater at lower ME concentration, indicating significant ME × EB interactions. Additionally, there were CP × EB interactions (P< 0.05) for duodenal villus height and villus height/crypt depth ratio, indicating that the effect of EB on these responses was more marked at lower dietary CP levels. An increase in dietary EB levels was accompanied by a linear increase in the concentration of total saturated fatty acids and a linear decrease (P< 0.05) in the concentrations of total polyunsaturated fatty acids in both breast and thigh meat. In conclusion, the positive effects of EB supplementation, particularly at a dietary inclusion level of 2 g/kg, were clearly evident in broiler chickens fed with low nutrient diets (−100 Kcal/kg ME and/or −5% CP and limiting amino acids) in terms of growth performance, nutrient digestibility, and gut morphology.

This study aimed to investigate the effect of eggshell temperature (ET) manipulations during incubation, in ovo feeding (IOF) of arginine, and post-hatch dietary supplementation with guanidinoacetic acid (GAA) on hatching traits and subsequent growth and physiological performance of hatched broiler chicks reared under subnormal temperature. In experiment 1, from d 8 of incubation onward, a total of 2,160 hatching eggs were randomly arranged in a 2 × 3 factorial design, in which the eggs were exposed to 2 ET (37.8°C or periodically low ET), and 3 IOF treatments (noninjected, diluent-injected, and 1% arginine solution-injected). In experiment 2, a total of 576 one-day-old male broiler chicks from 2 temperature conditions and 2 IOF treatment groups (noninjected and Arg-injected) were reared for 42 d with or without GAA supplementation in a 2 × 2 × 2 factorial design. Each treatment had 6 replicates with 12 birds each. A subnormal ambient temperature (17°C) was applied from 15 d onward to induce ascites. Results from experiment 1 showed a 2-way interaction between ET and IOF for embryonic mortality rate during 19 to 21 d of incubation and residual yolk weight at hatch (P< 0.05). A periodically low ET significantly increased yolk free body mass, first-grade chicks, and relative heart weight than an ET of 37.8°C. In the second experiment, overall average daily gain (ADG) was increased, but feed conversion ratio (FCR), ascites mortality, and serum thyroid hormones and corticosterone were reduced in the low ET group (P< 0.05). There were also IOF × GAA interactions for ADG and FCR (P< 0.05). IOF of arginine or dietary GAA increased serum nitric oxide concentration and jejunal villus height, but decreased ascites mortality (P< 0.05). In conclusion, a periodically low ET accompanied by IOF of arginine during incubation and posthatch dietary supplementation with GAA could be a useful strategy for improving the chick quality at hatch and subsequent improvements in post-hatch performance and ascites indices in cold-stressed broilers.

Colonization of the gastrointestinal tract by potentially pathogenic bacteria and their shedding in animal feces is a fundamental factor for both animal health and human food safety. This study was conducted to evaluate the efficacy of salinomycin (Sal), direct-fed microbial (DFM), and Ferulago angulatahydroalcoholic extract (FAE) against Campylobacter jejuniin broiler chickens in a 6-week pilot-scale study. A total of six hundred and seventy two 1-day-old broiler chickens were equally divided into 6 groups (each consisting of 8 replicates of 14 birds): negative control (NC; untreated and uninfected); positive control (PC; untreated, infected with C. jejuni); PC + Sal; PC + DFM; PC + 200 mg/kg of FAE (FAE200); or PC + 400 mg/kg of FAE (FAE400). All these groups (except NC) were challenged with C. jejunion day 15. The results showed that all experimental treatments improved (P < 0.05) average daily gain compared with the PC group, and the best value was observed in the NC and FAE400 groups throughout the entire experimental period (day 1–42). The overall feed conversion ratio and mortality rate, as well as the population of C. jejuni(day 24 and 42) and Coliforms (day 42) in the ileum and cecum, were higher (P < 0.05) in broiler chickens fed with the PC diet than for chickens in the other groups, except those in the FAE200 group. Immune responses revealed that among challenged birds, those that were fed diets DFM and FAE400 had significantly higher IgG (day 24 and 42), IgA (day 24), IL-6 (day 24), and gamma interferon (day 24 and 42) concentrations than the PC group. In conclusion, dietary FAE, especially at a high level of inclusion in broiler diet (400 mg/kg), could beneficially influence the immune status, as well as improve growth performance and intestinal microflora under Campylobacterchallenge, which was comparable to those of Sal and DFM supplements.

A study was undertaken to determine the effects of supplemental multicarbohydrase (MC) and butyrate glycerides (BG) on productive performance, nutritional, and physiological responses in laying hens fed corn- or wheat-based diets during a 12-week production period (from 50–62 wk of age). The experiment consisted of a 2 × 2 × 2 factorial arrangement of the treatments with 2 different basal diets (corn- or wheat-based diets), 2 concentrations of MC (0 or 200 mg/kg of diet), and 2 concentrations of BG (0 or 2 g/kg of diet). Each treatment had 6 replicates with 8 hens each. The interactions among diet, MC, and BG were observed for egg production (P = 0.048), feed conversion ratio (P = 0.005), and ileal Escherichia colicount (P = 0.043), indicating that the effects of MC and BG on these responses were more marked when wheat-based diet was fed. A diet × MC interaction (P < 0.05) was also detected for egg mass, eggshell breaking strength, jejunal viscosity, and digestibility coefficients of fat and ash. Replacing 100% of the corn with wheat in the diets of laying hens negatively affected (P < 0.05) yolk color index, eggshell thickness, digesta viscosity, jejunal morphology, and populations of ileal microbiota. By contrast, MC supplementation increased (P < 0.05) eggshell thickness, digestibility coefficients of energy and crude protein, and populations of Lactobacillusand Bifidobacteriumspp. in the ileum. Inclusion of BG also resulted in greater (P < 0.05) jejunal villus height and villus surface area, and digestibility coefficients of protein and ash, but lower (P < 0.05) populations of total bacteria, Salmonellaand E. coliin the ileum. Results indicate that while the complete substitution of corn by wheat has a detrimental effect on productive performance and gut health, the combination of MC and BG may have synergistic effects on improving productive performance and intestinal microbiota in laying hens fed the wheat-based diets during the late laying period.