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The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs fed a Saccharomyces cerevisiae fermentation product (SCFP) and subjected to exercise challenge in untrained and trained states. Thirty-six adult dogs (18 male, 18 female; mean age: 7.1 yr; mean body weight: 29.0 kg) were randomly assigned to control or SCFP-supplemented (250 mg/dog/d) diets and fed for 10 wk. After 3 wk, dogs were given an exercise challenge (6.5 km run), with fresh fecal samples collected pre- and post-challenge. Dogs were then trained by a series of distance-defined running exercise regimens over 7 wk (two 6.4 km runs/wk for 2 wk; two 9.7 km runs/wk for 2 wk; two 12.9 km runs/wk for 2 wk; two 3.2 km runs/wk). Dogs were then given exercise challenge (16 km run) in the trained state, with fresh fecal samples collected pre- and post-challenge. Fecal microbiota data were evaluated using QIIME2, while all other data were analyzed using the Mixed Models procedure of SAS. Effects of diet, exercise, and diet*exercise were tested with P

This study determined the Pectoralis (P) major mixed muscle protein turnover (PT) in two meat broiler lines, Line A and Line B, during the finishing grow-out feeding period (21-42 days) as affected by the dietary metabolizable energy (ME) levels and ambient temperatures. Experimental finishing diets consisted of 80, 90, 100, 110 and 120% ME of recommended nutrient guidelines for energy level. Fractional synthesis rates (FSR) or fractional degradation rates (FDR) were measured in P. major at day 36 and 42. Protein and fat mass gain were measured, and respective energy retention efficiencies as protein and fat (EREp and EREf) were determined. Metabolic heat production (HP) was also reported. Experimental feeding studies were conducted in cool season (24 hr mean: 69.91˚F and 63.98% RH) and in hot season (24 hr mean: 77.55˚F and 86.04% RH). Results showed that FSR or FDR values were not affected by dietary ME levels at day 36, whereas reduced FSR (p

Two broiler lines, Line A and Line B, were fed experimental diets from 22 to 42 d with objectives to determine effects of digestible amino acids (AA) to metabolizable energy ratios on feed intake (FI), performance, and processing yield. Experimental diets were formulated to 3,150 kcal/kg with 5 levels of digestible lysine (dLys)—80, 90, 100, 110, and 120% of recommended AA level giving g dLys/Mcal values of 2.53, 2.85, 3.17, 3.48, and 3.80, respectively. All other AA were formulated to a fixed ratio to dLys. A total of 4,050 chicks were utilized in each trial (9 replicate pens for each AA level and each line; 45 chicks/pen) conducted twice: one in hot environmental temperature (HT) (24 h mean ∼85.3 °F; 80.9% RH) and another in cool environmental temperature (CT) (24 h mean ∼71.6 °F; 61.7% RH). Results showed that FI was not impacted by dietary AA levels in HT for both lines. Higher FI (P

Developmental changes in hepatic methionine adenosyltransferase, cystathionine β-synthase, cystathionase, and glycine N-methyltransferase were determined in broiler chick embryos and hatched chicks by using radiometric and spectrometric methods. Hepatic free methionine, S-adenosylmethionine, S-adenosylhomocysteine, homocysteine, cystathionine, and cysteine levels were also investigated. Results showed an increase in hepatic MAT activity from E10 to E21 during embryogenesis, suggesting greater transmethylation rates throughout the rapid embryonic growth and development period. A strong positive correlation between embryo BW and MAT activity also supports this idea. The MAT specific activity continued to increase after hatching, but there was a negative correlation between chick BW and MAT activities from D1 to D49. This may indicate different MAT isozymes exist for chick embryo hepatic tissue compared to hepatic tissue of hatched chick and growing broilers. The developmental pattern of MAT isozymes could be critical for methionine metabolism to cope with the demand imposed on the embryo, chicks, and growing broilers. Additionally, the specific activity of hepatic CBS in chick embryos was determined to be lower compared to that observed in older broilers (35 and 49 days). Since liver CBS specific activity is at the lowest point from D1-7 in young chicks, the ability to convert adequate homocysteine to cysteine through transsulphuration may be limiting for cysteine synthesis at this time. Steady-state hepatic homocysteine levels in chick embryos and chicks may be a function of the rates of homocysteine formation, remethylation, and catabolism via the transsulphuration pathway. The present study indicates young chicks from D1 to D7 may have a limited ability for adequate transsulphuration; therefore, dietary cystine may be needed for optimum performance.

Phenylalanine and tyrosine are important amino acids for synthesis of proteins, catecholamine neurotransmitters, and melanin in canines. Since phenylalanine (Phe) is converted to tyrosine (Tyr), this experiment used the direct amino acid oxidation (DAAO) technique to determine the phenylalanine requirement and phenylalanine plus tyrosine requirements for growing Labrador Retrievers. The Phe requirement was separated from Phe plus Tyr requirement by supplementing the test diets utilized for Phe requirements with 1.48% crystalline Tyr. A total of twelve dogs were used in two trials to determine the Phe and Phe + Tyr requirements in growing puppies ( >14wk-1yr). Control diet was fed for two days, followed by a testing day where an experimental diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C] phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the dog’s body weight was supplied, followed by enteral feeding of [1-13C]Phe every 30 minutes, spanning a four hour period. Respiration masks were placed on each subject every 30 minutes (Oxymax, Columbus Instruments), 13CO2 collected, and enrichment determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a segmented model (JMP® Pro 15). Results showed that Phe mean and population safe requirements were 1.29 +/- 0.26 g/1000 kcal, while the Phe + Tyr requirements were 1.95 +/- 0.65 g/1000 kcal. Knowledge gathered through these studies is invaluable as both the Phe and Phe plus Tyr dietary requirements for growing Labrador Retriever puppies were determined.

Even the highest quality ingredients undergo oxidative stresses during manufacturing processes, increasing the nutrition delivery challenges facing large-scale feed manufacturing. In this study we investigate the impact of increasing peroxide values (PV) in the chemical composition in rendered chicken meal (CM) and chicken by-product meal (CB). To determine canine acceptance, working Labrador Retrievers (20 male; 20 female) were used in a preliminary novel aromatic palatability test as well as a traditional two-pan palatability test. PV sample levels ranged from < 10-200 (CB or CM Sample identification: 1.~ < 10, 2.~20-50, 3.~50-100, 4.~100-200). Results indicate that dogs preferred reduced peroxide values in both aromatic (p= < 0.05) and traditional 2-pan palatability trials (p= < 0.05). Preference testing results correlated with extensive physical and chemical data obtained using a Heracles Electronic Nose ultra-fast gas chromatography (UFGC), solid-phase micro-extraction (SPME), and gas chromatography-mass spectrometry (GC-MS). The broad-spectrum analysis utilized solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) to identify 177 nonpolar compounds, 340 polar compounds, and 457 volatile compounds. The overall composition did not vary; however, individual compounds had strong linear correlations with peroxide value. In chicken by-product meal samples, 38 compounds were linearly correlated; in chicken meals, 27 compounds were identified (r2>0.90). These data: 1) introduces novel quality control markers for further research and showcases the potential for greater accuracy by developing product specific markers; 2) confirms that the chemical differentiation between peroxide values went beyond lipid oxidation and highlighted multiple compounds of interest for further study; and 3) emphasizes greater levels of peroxide in pet foods have unfavorable palatability. This research was funded by the Fats and Protein Research Foundation.

Conditions which affect humans are often closely followed by our companion animals, especially in aging populations. Canines often present with muscle wasting diseases such as sarcopenia and cachexia as a result of aging or chronic disease. In this 26wk study, our goal was to evaluate the effects of feeding 1.5x AAFCO CP from whey protein isolate and a pea isolate compared to feeding senior dogs a standard AAFCO CP diet (45g CP/1000 kcal DM) on body composition in exercised senior Labrador Retrievers. Thirty-six (36) Labrador Retrievers (18m/18f; 8-12yrs) were sorted into three equal groups and fed basal AAFCO diet plus hydrolyzed whey isolate, pea isolate, or added fat and sugar (control). All dogs ran 1.6km run twice weekly throughout the trial. Body composition was determined by dual-energy x-ray absorptiometry (DXA) at Weeks 0, 12, 20, and 26. All dogs were weighed weekly and feed intake measured daily. Body weights and feed intake were similar between groups. Whey group gained 1.69% fat and 0.6kg fat mass compared to control group gaining 7.97% fat and 3.05kg fat mass (p=0.045; p=0.005). From Wk0 to Wk26, whey group lost only 0.38kg lean/fat ratio compared to control group’s -1.75kg loss (p=0.021). From Wk12 to Wk26 and Wk18 to Wk26, whey group maintained a higher lean:fat ratio compared to pea and control group (p=0.101; p=0.049). Based on these results, senior Labrador Retrievers fed 1.5x AAFCO CP from basal plus hydrolyzed whey protein isolate during an exercise regimen maintained higher lean:fat ratio compared to seniors fed basal plus pea protein and seniors fed only basal. Senior dogs fed hydrolyzed whey protein isolate also had increased fat loss vs seniors consuming only the basal diet.

The aim of this experiment was to evaluate the effect of undenatured type II collagen supplementation on inflammation and pain using gait analysis and industry-accepted pain and mobility questionnaires during an exercise regimen in healthy dogs. Forty healthy Labrador Retrievers (20 male/20 female; range: 5 to 12 yr) were sorted into two groups: undenatured type II collagen group receiving 40 mg UC-II product (10 mg total collagen and ≥3% undenatured type II collagen) and placebo group receiving 40 mg maltodextrin daily by capsule. After 2 wk loading, all dogs began an 11 wk endurance exercise regimen consisting of two weekly runs, starting at 5 km and increasingly incrementally to 8 km, with one final 16 km run. Gait analysis was performed at baseline; before, 24 and 48 h after the first 5 km run; and before, 24 and 48 h after the final 16 km run. Gait analysis was calculated to obtain a Four Rivers Kennel (FRK) Inflammation Index score. Dogs were scored according to the Liverpool Osteoarthritis in Dogs (LOAD) and Canine Brief Pain Inventory (CBPI) assessments at baseline, before and after the first 5 km run, and before and after the final 16 km run. On the LOAD questionnaire, undenatured type II collagen group had improved “how active is the dog” (P = 0.03) and less “stiffness after a lie down” (P = 0.041) compared with placebo at pre 5 km. Undenatured type II collagen appeared to mitigate the development of pain after exercise compared with placebo, as related to the CPBI assessment. Undenatured type II collagen dogs had lower “pain at worst” pre 5 km (P = 0.021), “pain at least” post 5 km (P = 0.015), “pain at average” post 5 km (P = 0.046), and “pain as it is now” post 16 km (P = 0.006) compared with placebo dogs. Undenatured type II collagen was more effective than placebo at mitigating inflammation on gait analysis per the FRK Inflammation Index. Undenatured type II collagen dogs had a 6.42 lower FRK Inflammation Index score at 24 h post 5 km (P = 0.032) and 6.3 lower score at 24 h post 16 km (P = 0.029), indicating the mitigation of inflammation on gait analysis. When considering the change between timepoints, undenatured type II collagen had a lower increase in FRK Inflammation scores compared with placebo for baseline to pre 5 km (P < 0.001), pre 16 km to 24 h post 16 km (P = 0.028), and pre 16 km to 48 h post 16 km (P = 0.027). Undenatured type II collagen supplemented Labrador Retrievers improved pain assessment variables and improved FRK Inflammation Index on gait analysis.

SUMMARY High-quality protein feeds are needed in ecological and organic poultry production. Feeds that are rich in methionine (MET) are particularly important because synthetic amino acids are generally prohibited in organic livestock production. Bigheaded carp present an opportunity as feed because they are an invasive fish species that are high in protein and MET. A carp-based meal (CBM) was prepared using innovative dry extrusion, and proximate analysis and nutritional analyses were conducted. The digestible amino acids and true metabolizable energy (TMEn) of the CBM were determined using a colony of cecetomized adult roosters. Starter and grower diets were formulated with CBM and tested in a broiler feeding trial. Diets were high overall in protein, but formulated without synthetic MET. Day-old chicks were randomly assigned to pens of 30 chicks belonging to 1 of 2 treatments (CBM or control containing synthetic MET), with 8 replications. Body weights, feed intake, and feed conversion ratio (FCR) for starter (0–21 d), grower (22–42 d), and overall periods (0–42 d) were analyzed using 1-way ANOVA. The weight gains, feed intake, and FCR did not differ between treatments (P > 0.05) for the overall period (0–42 d). The results indicate that invasive bigheaded carp can be harvested and dry extruded into a novel meal, providing not only a natural and sustainable source of MET, but also an environmental service for damaged aquatic ecosystems in the U.S.

Body composition (BC) analysis is important because the modern broiler is one of the most efficient animals in producing protein for human consumption, and a proper nutrition could potentiate this meat production. BC by chemical analysis was analyzed in 151 broilers from 1to 60 d of age. Birds were fed mash feeds ad libitum in four phases (starter 1 to 14d, grower 15 to 28 d, finisher 29 to 42 d, and withdrawal 43 to 60 d). Gompertz 3P model, multiple linear regression, and CRD with ANOVA analysis were used in the experimental design using JMP pro 2015. The growth in terms of body weight, protein, fat, minerals (Ca and P) followed a Gompertz 3P model with similar growth rates of about 4.9% per day and the maximum growth was obtained at about 34 d of age. Body weight ranged from 56 to 4184 g, water from 683 to 751 g/kg, protein from 154 to 182 g/kg, fat from 53 to 101 g/kg, minerals (ash) from 17.9 to 22.5 g/kg (AS IS basis). Broiler protein ranged from 563 to 613 g/kg, fat 197 to 317 g/kg, minerals 65.2 to 86.6 g/kg, calcium 11.7 to 18.9 g/kg, and phosphorus 10.3 to 15.3 g/kg dry matter (DM) basis. The calorific coefficients for protein and fat were determined by multiple regressions and resulted in 5.45 ± 0.09 kcal/g for protein and 8.95 ± 0.16 kcal/g for fat. These two coefficients can be used to predict the body energy content or energy of gain. The protein: fat ratio was the highest at day 1 and decreased gradually until day 60. The BC in terms of water, protein, and fat changes with age, water being reduced and protein and fat increased towards d60. Mineral composition remained constant at the end of growth but some fluctuations occurred during the grower period. The understanding of the dynamics of BC will bring new opportunities to study and change feed strategies and increase the feed efficiency for meat in the modern broiler.

This study aims to model the relationship among performance, whole body composition, and processing yield through meta-regression. Scientific papers found in Scopus and Google Scholar were included if they reported results and variability values of an actual experiment in the three mentioned groups of variables using a single broiler genetic line. Weighted mean effect sizes were determined with a random model, the risk of bias was determined, and heterogeneity was considered an indicator of usefulness. Meta-regressions considered the effect sizes of the response variable and the percent change in one or more variables as predictors. A 78-row database was built from 14 papers, including nine factors tested on 22,256 broilers. No influencing bias was found, and the data was determined useful. Meta-regressions showed that the changes in body weight gain (BWG) are inversely related to the effects in feed conversion ratio (FCR) (p < 0.001) and that the changes in FCR and effects in protein-to-fat gain (PFG) are directly related (p < 0.001). The changes in PFG and the effects on carcass conformation or the market value of birds are directly related (p < 0.001). In conclusion, body composition predicts carcass conformation and its market value, supporting its use to predict the economic value of broilers.

Providing protein to growing puppies in accurate amounts ensures that animals have enough energy and nutrients for depositing muscle, growing bones, and maintaining joint health. Inclusion amounts must be provided at correct doses, considering a diet with excess protein can lead to harmful outcomes such as hyperkalemia or acidosis. To determine the protein requirements in growing Labrador Retrievers, the indicator amino acid oxidation (IAAO) technique was utilized in six puppies (>14 wk-9 mo). Dogs were supplied with constant dietary Phe across diets. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the body weight of the subject was supplied, followed by [1-13C]Phe doses every 30 minutes, spanning a four-hour period. A respiration mask was placed on each subject every 30 minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). IRMS results were converted to atom percent excess (APE) and analyzed using a segmented model of best fit (JMP Pro 16). The outcome of this experiment determines that if essential amino acids and non-essential amino acid nitrogen requirements are met, Labrador Retriever puppies will have mean and population safe requirements (mean±2SD) of 47.5 ± 1.325 g/1,000 kcal.

The aim of this experiment was to evaluate the effect of undenatured type II collagen supplementation on inflammation and cartilage degeneration after exercise in healthy dogs. Forty healthy Labrador Retrievers (20 male/20 female; range 5-12 yr; average 8 yr) were sorted into two groups: undenatured type II collagen group receiving 40 mg UC-II (10 mg collagen type II/min. 3% undenatured type II collagen; Lonza Consumer Health, Inc.) and placebo group receiving 40 mg maltodextrin daily by capsule. After 2-wk loading, all dogs began an 11-wk endurance exercise regimen consisting of two weekly runs, starting at 5 km and increasing incrementally to 8 km, with one final 16 km run. Blood samples were collected at baseline, pre and post first 5 km run, and pre- and post-16 km run. Activity per kilometer was greater in male undenatured type II collagen vs. male placebo over all runs (P = 0.004), and average moving speed was greater in all undenatured type II collagen dogs compared with placebo over all runs (P < 0.001). Hematology analysis indicated that during the first insult, undenatured type II collagen dogs had a greater lymphocyte count (P < 0.001) and lymphocyte percentage (P = 0.001) vs. placebo dogs. Undenatured type II collagen dogs had a lesser neutrophil percentage (P = 0.042) and neutrophil to lymphocyte ratios (P = 0.001) compared to placebo dogs. For the final insult, undenatured type II collagen dogs had greater lymphocyte percentage (P = 0.013) and lesser mean corpuscular hemoglobin concentration (P = 0.043) compared with placebo dogs. Both groups had significant changes between timepoints for several hematological parameters. Biomarker IL-6 was lesser in undenatured type II collagen dogs compared with placebo at post 5 km (P = 0.037). Cartilage oligomeric matrix protein (COMP) was lesser in undenatured type II collagen dogs at post 16 km (P = 0.023), and only the placebo dogs had a significant increase in COMP from pre to post 16 km (P = 0.021). In summary, Labrador Retrievers supplemented with undenatured type II collagen had decreased inflammation and cartilage degeneration compared with nonsupplemented dogs during exercise.

Saccharomyces cerevisiae fermentation product (SCFP) is a dietary postbiotic compound shown to support digestive health and immune function in several species. Two studies were performed to evaluate the effects of SCFP (Diamond V Mills, Inc.; Cedar Rapids, IA) in canines exposed to exercise and transport stress. In both studies, 36 Labrador Retrievers (18 males/18 females) >5y were used. Study 1 consisted of a 3-wk adaptation period followed by a 14-wk series of distance-defined running exercise regimens (DDER) with subjects randomly allocated to three groups of 0 mg/d SCFP, 250 mg/d SCFP, or 500 mg/d SCFP. Study 2 consisted of a 3-wk adaptation period followed by an 8 wk phase of DDER and a final, single transport stress event. Subjects were randomly allocated to two treatments of 0 mg/d SCFP and 250 mg/d SCFP. Parameters examined over the two studies included body composition, body weight, feed intake, activity, running speed, stool quality. The following serum biomarkers were also measured: saliva cortisol (CORT), total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), c-reactive protein (CRP), creatine kinase (CK), haptoglobin (HAP), serum amyloid A (SAA), TNF-α, immunoglobulin E (IgE), and immunoglobulin G (IgG). Subjects fed SCFP exhibited numeric net increases in lean mass (Table 1), numeric increases in stool quality, and significantly higher activity during exercise (P < 0.05) vs CON (Table 2). The 500 mg/d SCFP group exhibited lower CK (P < 0.03), increased HAP (P < 0.001), increased SAA (P < 0.05), increased TNF-α (P < 0.007), increased CORT, improved TAC (P < 0.001), reduced TBARS (P < 0.01), IgE (P < 0.001) and IgG (P < 0.001), and increased CRP during transport (P < 0.001) (Table 3). These results demonstrate that Labrador Retrievers supplemented with SCFP may exhibit improved vitality, utilization of nutrients, immune function, and reduced cellular damage when subjected to exercise and transport stress.

An important function of feeding large breed puppies is providing appropriate amounts of calcium and phosphorus, which is used in skeletal mineralization during growth. National Research Council stated calcium requirements are 0.8–1.2%, and phosphorus 1.0–1.6%. The objective of this study was to compare a high calcium diet (Ca: 5.7%; P: 2.9%) (Nature’s Logic Canine Beef Meal Feast; Nature’s Logic) (HC) to a normal control diet (Ca: 1.6%; P: 1%) (Purina Puppy Chow; Nestle Purina) (CON) in growing Labrador Retriever puppies. Thirty-two puppies (16 HC/16 CON) were used in two 10wk modified AAFCO large breed puppy growth trials. Body weights were measured weekly, feed intake daily, and digestibility, body composition, hematology, chemistry, and bone metabolism biomarkers were measured at 8wks, 13wks, and 18wks of age. All puppies passed all AAFCO large breed puppy growth requirements, including veterinary exams, body weight gain, and bloodwork parameters. Both groups had similar average weight gains from baseline to the end of the trial. No significant differences in bone mineral density were found between HC and CON groups at any timepoint. No significant differences were found between groups after baseline for parathyroid hormone, calcitonin, or tartrate resistant acid phosphatase bone metabolism biomarkers. Total tissue mass, fat mass, and lean mass were lower in the HC group compared to CON group (P < 0.05), likely due to lower caloric content and metabolizable energy in the HC diet than expected. Calcium digestibility was significantly higher in HC diet vs CON diet (P < 0.01). Based on this data, a high calcium diet had no negative impact on major physiological parameters in growing Labrador Retriever puppies.

The objective of this trial was to develop an index system to identify inflammation in Labrador Retrievers using a pressure walkway system. Gait analysis data can be difficult to interpret between treatment groups or for identifying low grade inflammation. To calculate the Total Inflammation Index™, the distance away from the ideal score was calculated for four parameters for each dog, including gait lameness score, total pressure index, step/stride ratio, and hind reach. These values were equally weighted and added together to produce the Total Inflammation Index™. For validation, the Total Inflammation Index™ values were compared to biomarker data for inflammation including cartilage oligomeric matrix protein, interleukin-6, creatine kinase, and c-reactive protein. Forty Labrador Retrievers (20 male/20 female) were used in this trial. All dogs were passed over the pressure walkway (Gait4Dogs; CIR Systems, Inc) to obtain gait analysis at baseline, 24h prior to the first 5km run, 24h after the first 5km run, 24h prior to the final 16km run, and 24h after the final 16km run. All biomarkers and the Total Inflammation Index™ were both significantly lower at the pre-exercise timepoints and elevated after post-exercise timepoints (P < 0.01). The Total Inflammation Index™ had significant correlation between timepoints and all biomarkers, including cartilage oligomeric matrix protein (P < 0.01), interleukin-6 (P < 0.05), creatine kinase (P < 0.01), and c-reactive protein (P < 0.05). The Total Inflammation Index™ appears to be a valid assay to evaluate generalized inflammation in Labrador Retrievers, and is in agreement with inflammatory biomarker values.

Woody breast (WB) is a major myopathy in broilers characterized by hardness of the breast fillet and can be evaluated by human palpation with a severity scale of 0 (normal) to 3 (severe). The objective of this study was to determine fillet dimensions and meat quality factors that are associated with WB scores that may potentially be used for sorting purposes. A total of 206 broiler breast fillets (deboned at 3 h postmortem) were collected and scored for WB.Thickness and length (overall, cranial, caudal, and keel regions) of the Pectoralis major (whole butterfly) were measured with a caliper. Compression force (CF), pH, and color were measured. The right side of the butterfly fillet was frozen at −20°C for 48 h and thawed for 24 h, and then CF was measured along with cook loss, Meullenet-Owens Razor Shear, and blunt Meullenet-Owens Razor Shear. Pearson correlation coefficients and nominal logistic regression were determined.Measurement responses were compared for 4 categories of WB. The keel length measurement on the breast showed no difference (P > 0.05). However, the thickness was moderately correlated with WB score (r = 0.67) and could differentiate between the scores. In addition, CF of right side was higher than left side of fillets (P < 0.05). Freezing/storage significantly decreased (P < 0.05) CF of thawed fillets compared to chilled (nonfrozen) fillets. Cook loss increased (P < 0.05) as severity for WB increased. Peak counts for Meullenet-Owens Razor Shear and blunt Meullenet-Owens Razor Shear were higher (P < 0.05) for the severe compared to the lower levels of WB severity. In conclusion, meat quality differences were evident among the WB categories, differences in CF were observed between right and left fillets, and freezing/storage decreased hardness of fillets. Breast fillet dimensions along with L* value may potentially be used to identify WB, and this model of prediction of WB could be used in the industry to select the different WB categories in the development of sorting methods.

The remethylation of homocysteine to methionine is important for chick embryos to sustain the S-adenosylmethionine transmethylation reactions, which are essential for the rapid proliferation of cells. Developmental changes in hepatic 5-methyltetrahydrofolate-homocysteine methyltransferase (MFMT), betaine-homocysteine methyltransferase (BHMT) and hepatic serine hydroxymethyltransferase (SHMT) were determined in E10-21 Cobb 500 broiler chick embryos and hatched chicks from D1-49. Hepatic levels of free serine, glycine, putrescine, spermidine and spermine levels were also determined. Analyses showed hepatic MFMT-specific activity doubled from E10 to E12, with remaining embryo development experiencing small fluctuations in activity through E21. Hepatic MFMT doubled immediately after hatch, with peak activity occurring at D3. Afterwards, hepatic MFMT-specific activity steadily declined from D7-49. Hepatic BHMT activity was higher from E10 to E16 of embryogenesis, decreased rapidly at E17 and remained lower through E21 (p < .05). Hepatic BHMT-specific activity was also lower in chicks, with the exception of a peak in specific activity on D7. BHMT activity returned to lower levels by D21. Throughout embryogenesis, hepatic SHMT activity in chick embryos remained relatively constant except for a decrease at 13E, followed by an increase at 14E. Maximal activity of SHMT was found the first day post-hatch. Additionally, SHMT activity was significantly lower in growing chicks than that in embryos. Hepatic-free serine and glycine levels were negatively correlated with SHMT in hatched chicks. Hepatic polyamine, putrescine and spermidine shared a similar development pattern: peak level in the middle of incubation, low at late embryogenesis and lowest during the post-hatch period except an increase within one week after hatch. The sharp increase in hepatic concentrations of glycine, serine and putrescine, along with increased specific activities of MHMT, BHMT and SHMT from D1-7, suggests that methionine conservation (remethylation from homocysteine) and glycine/serine is critical for young chicks for organ growth, maturation, and development.

This multiple-case study was conducted to evaluate claims that the literature on the recruitment of science majors into science teaching is sparse and unable to adequately explain why undergraduates decide to pursue science teaching. I interviewed six undergraduate science majors who have committed to an initial science teacher preparation program to ascertain their motivations for choosing a career in teaching. This analysis reveals that the literature has not adequately identified all the reasons why a group of science majors decided to pursue science teaching. Four novel motives were identified which should inform future research into science teacher recruitment.

The present study was conducted to determine whether the addition of β-mannanase in broiler feed changes hormonal profiles in the blood and broiler performance and nutrient availability. Five hundred and four Cobb male chickens were studied during d 7 to 21. Three corn-soybean meal (SBM) based diets 1) Low SBM (18% SBM); 2) High SBM (31% SBM); and 3) High SBM+GG (31% SBM + Guar Gum (GG) 0.5%) with 3 levels of β-mannanase (0, 200, and 400 ppm) were mixed to produce 9 diets. A factorial design 3 × 3 was performed with JMP pro 13 (SAS, 2017). Analysis of variance and contrast analysis were used to test significance level at P < 0.05. Glucose (190 and 188 mg/dL) was increased with 200 and 400 ppm of β-mannanase, respectively, compared to control (182 mg/dL) in the fasted state (P < 0.037). Glucose was higher in chicks fed with the High SBM and High SBM + GG diets but lower in the fasted re-fed state (P < 0.01). Insulin was higher with 200 and 400 ppm added β-mannanase in the fed state (P < 0.021). Insulin-like growth factor-1 was higher with 400 ppm added to High SBM+GG. β-mannanase improved feed conversion ratio (FCR) 9 points with 400 ppm in High SBM diet (P < 0.01) and 16 and 18 points with 200 and 400 ppm, respectively, added to the High SBM+GG diet (P < 0.01). Viscosity decreased from 19.2 to 7 cps with both enzyme doses in the High SBM + GG diet (P < 0.01). Digestible energy was +152 kcal/kg with 400 ppm β-mannanase in the High SBM diet and +200 kcal/kg with both levels of enzyme in High SBM+GG diet. Digestibility of amino acids was improved from 0.8 to 3.6% with β-mannanase in High SBM+GG diet (P < 0.05). In conclusion, chicks fed with High SBM and High SBM+GG diets with added β-mannanase significantly improved blood glucose and anabolic hormone homeostasis, FCR, digestible energy, and digestible amino acids compared to chicks fed with same diets without β-mannanase.

Changes in heat production (HP) and body composition (BC) in modern broiler breeders can provide means to understand nutrient utilization. Twelve Cobb 500 breeders were evaluated 10 times from 26 to 59 wk of age. The same wired caged breeders were moved to respiratory chambers connected to an indirect calorimetry to obtain oxygen consumption (VO2) and carbon dioxide production (VCO2), HP, and respiratory exchange ratio (RER). The same hens were evaluated for BC using a dual X-ray absorptiometry (DEXA). Data were analyzed during light (16 h) and dark (8 h) period using a mixed model to evaluate calorimetry parameters, a factorial design 2 × 10 for normalized calorimetry parameters, and Complete Randomized Design (CRD)-one way ANOVA for BC. Means were separated by Tukey-Honest Significant difference (HSD). HP increased with age (d) in 0.152 kcal/d, VO2 and VCO2 were 0.031 and 0.024 L/d per each increase in age (d), respectively. In the light period, hens consumed +17.4 L/d VO2 and produced +18.9 L/d VCO2 (P < 0.01). HP during the dark period was 84 kcal/kg0.75 and during the light period was 115 kcal/kg0.75. RER decreased with age until 43 wk and remained the same until 59 wk suggesting more fat and/or protein being oxidized at later periods of production. Lean body mass ranged from 642 to 783 g/kg during the whole study reaching the lowest at 37 and 50 wk and the highest at 26 to 33 wk (P < 0.01). Body fat ranged from 168 to 261 g/kg with the lowest at 26 to 33 wk and the highest at 50 wk of age (P < 0.01). Broiler breeder females may be catabolizing fat energy reserves from 50 wk onwards when the egg production is reduced, and HP increased at 54 and 59 wk (P < 0.01) due to higher energy required for maintenance of a higher lean mass structure. Broiler breeders change nutrient fuel use during egg production. Indirect calorimetry and DEXA can be used to pursue further feed strategies to maximize egg production and maintain a healthy breeder.

Two 5-d bioassays were conducted to explore the P physiological threshold in broilers based on plasma inorganic P (iP), urinary P and Ca, and excreta P and Ca measurements in non-colostomized and colostomized broilers fed with different concentrations of non-phytate P (NPP) and Ca. In Experiment 1, 80 40-day-old Cobb 500 non-colostomized male broilers were assorted into 8 groups consisting of 10 broilers each and placed in individual metabolic cages. Similarly, 8 colostomized broilers of same age were allotted to 8 individual metabolic cages. The experimental diets consisted of a corn soybean meal basal containing 0.17% phytate P (PP) with 8 concentrations (0.08, 0.13, 0.18, 0.23, 0.28, 0.33, 0.38, and 0.45%) of NPP. The dietary Ca concentration was maintained at 0.5% by adjusting a 185-micron particle size limestone with each concentration of added P from added calcium phosphate, dibasic, monohydrate. After Experiment 1, broilers were fed a standard grower diet for 5 d and Experiment 2 was conducted the same as Experiment 1; however, Ca was maintained at 0.9% for all test diets. Plasma iP, urinary P and Ca, and total P (TP) and Ca retention along with phytate P hydrolysis were measured. At 0.5% Ca dietary level, the inflection points for dietary NPP obtained from segmented line regression analysis for plasma iP, urinary P, and urinary Ca were 0.26% (±0.04 SE), 0.28% (±0.01 SE), and 0.30% (±0.04 SE), respectively. The similar values for 0.9% Ca diets were 0.27% (±0.03 SE), 0.21% (±0.03 SE), and 0.30% (±0.0 SE), respectively. In summary, the present findings suggest that an increased dietary NPP would increase plasma inorganic P concentration along with increased % retention of TP and NPP until the broilers reach a point of physiological steady state (7.51 mg iP/dL - 8.13 mg iP/dL as found in this study). Excess P beyond physiological threshold is eliminated in urine coupled with decreased % retention.

The food production system needs to be sustainable including poultry sector to feed the increasing global population. An accepted economical and environmental approach of broiler production is to produce larger broilers faster while using less feed. Broiler production is aimed at producing consumable meat and meat products. The global broiler meat market has evolved over the years with increasing selection pressure shifted toward attaining yield characteristics for increased cut-up parts such as breast and thighs. There is a shift toward a big bird market in the U.S. with approximately 70% of the broiler meat produced from large birds (>2.72 kg). Genetic selection of broilers for quantitative traits such as growth rate and lean muscle mass without increasing the fat mass has altered broiler physiological homeostasis to adapt toward the larger rates of muscle protein turnover. Physiological stresses created due to selection pressures in broilers have produced several muscle myopathies including an emerging one called woody breast myopathy. The sustainable broiler production practice may require humane consideration of raising broilers in less stressful grow-out regimes that will have minimal impact on broiler metabolic health. Another sustainability approach of broiler production toward feed efficiency lies on understanding dietary formulation approach of amino acids and energy that promote optimal nutrient utilization and minimal nutrient output to environment while also fulfilling the growth demands and body composition changes associated with increased protein gain in current meat broilers brought by the genetic progress.

Methionine and cystine are often considered limiting amino acids in canine diets but limited requirement studies have been conducted especially for different life stages. Eighteen Labrador Retrievers (6 pups (>14 wk-9 month), 6 adults, and 6 seniors [>8yr)] were utilized in feeding studies to evaluate the changing requirements of methionine (Met) and total sulfur amino acids (TSAA) as canines age. For this study, the indicator amino acid oxidation (IAAO) technique was utilized to determine the amino acid (AA) requirements in each of the three age groups. Dogs were subjected to diets ranging from deficient to excess, with indispensable amino acids formulated at 1.6x NRC values. To allow for adaptation, a control diet with same dietary ingredients, protein and amino acid levels was fed for two days prior to feeding the test diets on the third day. On test day, a baseline breath sample was collected for determining CO2 production using a respiration mask (Oxymax, Columbus Instruments). A priming dose of L-[1-13C] phenylalanine (Cambridge Isotope Laboratories, Inc.) based on body weight was utilized, followed by [1-13C] Phe doses every 30 minutes, spanning a four hour period. After each dose 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP® Pro 16). A segmented line regression showed Met and TSAA mean and population requirements for pups (>14 wk-9 mo.) were 0.78 ± 0.16 and 1.53 ± 0.21 g/1000kcal (mean ± 2SD), respectively. Meanwhile, for adults, mean and population requirements for Met and TSAA were estimated to be 0.68 ± 0.19 and 1.4 ± 0.30 g/1000kcal (mean ± 2SD), respectively, and for seniors, Met and TSAA mean and population requirements were determined to be 0.62 ± 0.17 and 1.27 ± 0.23 g/1000kcal (mean ± 2SD), respectively.

White Striping (WS) and Woody Breast (WB) are 2 conditions that adversely affect consumer acceptance as well as quality of poultry meat and meat products. Both WS and WB are characterized with degenerative myopathic changes. Previous studies showed that WS and WB in broiler fillets could result in higher ultimate pH, increased drip loss, and decreased marinade uptake. The main objective of the present study was to compare the proteomic profiles of muscle tissue (n = 5 per group) with either NORM (no or few minor myopathic lesions) or SEV (with severe myopathic changes). Proteins were extracted from these samples and analyzed using a hybrid LTQ-OrbitrapXL mass spectrometer (LC-MS/MS). Over 800 proteins were identified in the muscle samples, among which 141 demonstrated differential (P < 0.05) expression between NORM and SEV. The set of differentially (P < 0.05) expressed proteins was uploaded to Ingenuity Pathway Analysis® (IPA) software to determine the associated biological networks and pathways. The IPA analysis showed that eukaryotic initiation factor-2 (eIF-2) signaling, mechanistic target of rapamycin (mTOR) signaling, as well as regulation of eIF4 and p70S6K signaling were the major canonical pathways up-regulated (P < 0.05) in SEV muscle compared to NORM. The up-regulation of these pathways indicate an increase in protein synthesis which could be part of the rapid growth as well as cellular stress associated with ongoing muscle degeneration and the attempt to repair tissue damage in SEV birds. Furthermore, IPA analysis revealed that glycolysis and gluconeogenesis were the major down-regulated (P < 0.05) canonical pathways in SEV with respect to NORM muscle. Down-regulation of these pathways could be the reason for higher ultimate pH seen in SEV muscle samples indicating reduced glycolytic potential. In conclusion, comparison of proteomic profiles of NORM and SEV muscle samples showed differences in protein profile which explains some of the observed differences in meat quality parameters. Future studies based on these differences could provide valuable insights into various cellular changes and identification of biomarkers related to WS and WB.

Pet food made from fresh and rendered high quality meat products are considered safe and nutritious products. Currently the main assessment of meat freshness and fat products is based on peroxide values (PV), quantifying secondary oxidation products such as aldehydes, ketones, and alcohols. Research on how rancidity or peroxidation affects the health/safety of pets has not been adequately investigated. Exploring how Labrador retrievers interact with PV associated aromas, the goal was to observe any correlations in canine aromatic preference to differing poultry meal PV levels. A pilot study was conducted to gather preliminary data and screen 60 Labrador Retrievers (30 male/30 female) for those best suited for this novel aromatic palatability approach. 10 Labrador Retrievers (5 male/5 female) were hand selected from the original group of 60, according to their willingness to interact repeatedly with the aromatic boxes designed to prevent consumption while allowing interaction with varied PV poultry meal aromas. Many dogs lost interest quickly when they learned they could not get to the inside contents of the boxes, making the pilot study a crucial step in the preliminary selection process. First approach was recorded for both trials as well as time spent interacting. Time spent at each box was converted to ratios and both were statistically analyzed. Data falling outside 2 standard deviations from the mean were deemed outliers and excluded from analysis. Ratio analysis examined over both trials pointed to a higher peroxide value (PV) preference, when paired with sample 1, especially sample 5. PV levels 2, 4, and 5 showed significantly higher (p=< 0.05) interaction times and 6 neared significance (P = 0.08), compared to PV level 1. Further exploration could compare all PV levels to one another, determining if a specific threshold or range of preference exists within the 6 levels we examined in this study.

Although nutrient profiles for canines have been developed in the past, the need to update amino acid (AA) requirements has gained importance as genetic selection changes the recommended nutrients. Correctly feeding AA to canines can have enormous effects, considering a deficiency or excess of such nutrient can lead to weight loss, disease, or in some cases, death. Amino acid requirements can be determined through the nitrogen balance or indicator amino acid oxidation (IAAO) methods. In this experiment, the IAAO technique was used to determine the threonine (Thr) requirement in Labrador retrievers. A total of six dogs (6 adult and 6 senior) were subjected to six diets with varying levels of Thr, ranging from deficient to excess. Diets were formulated to 1.6x NRC values for all indispensable amino acids. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer AA was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP® Pro 15). The segmented line regression showed that the Thr mean and population requirements were determined to be 1.21 ± 0.24 and 0.92 ± 0.17 g/1000kcal (mean ± 2SD) for adult and senior dogs, respectively. As the pet food industry becomes more specialized in diets relating to aging, and diseased canines, updating the amino acid requirements related to such animals is increasingly important.

Collagen protein has been considered as major culprit to myopathy condition affecting Pectoralis major, called woody breast (WB) in Gallus gallus domesticus (broiler). The WB myopathy is characterized by macroscopic stiffness of P. major and the affected tissue have reduced protein quality. This study measured the in-vivo soluble (S-) and insoluble (I-) collagen fractional synthesis and degradation rates (FSR and FDR) in P. major over typical grow-out cycle of broiler using stable isotope of 1-13C proline as metabolic tracer. Collagen content and muscle fiber histomorphology of P. major were also assessed simultaneously. The FSR and FDR for S- and I-collagen decreased over age, however FSR remained higher than FDR suggesting collagen was accreting during the grow-out period. This was reflected by increment in total collagen content in P. major in maturing broiler. Histomicrographs showed myodegeneration occurring as early as 21 days followed by greater accumulation of collagenous tissue in perimysial and endomysial connective tissue spaces of muscle fibers as bird aged. The findings suggest that reduced turnover of collagen in P. major at the later age of bird could have evolved due to adaptive physiological feedback mechanism against further synthesis and deposition of collagen in the extracellular matrix.

Two broiler lines A and B were fed experimental diets from 21 to 42 days with an objective to determine Pectoralis major protein turnover (PT) as affected by the dietary amino acid (AA) levels and ambient temperature. Experimental diets (n = 9 replicate pens per diet) were formulated to 3,150 kcal/kg with five levels of digestible lysine (dLys) -80, 90, 100, 110 and 120% of recommended AA level giving g dlys/Mcal values of 2.53, 2.85, 3.17, 3.48 and 3.80 respectively. All other AA was formulated to a fixed ratio to dLys. Fractional synthesis or degradation rates (FSR or FDR) of P. major were measured on day 36 and day 42 for all dietary treatment levels for both broiler lines using stable isotope of AA (15 N-phenylalanine) as metabolic tracer. Experimental feeding studies were conducted once in hot season (24-hr mean ~ 85.3°F; 80.9% RH) and repeated in cool season (24-hr mean ~ 71.6°F; 61.7% RH) of the year. The FSR values increased (p .05). Similar trends but elevated values of FSR and FDR in cool season than in hot season were recorded for both the lines. Line B showed the higher mixed muscle protein accretion (%/D) than Line A by actually increasing the FSR which was correlated by higher lean mass deposition and higher feed intake (p < .05). The overall findings indicated that PT response in P. major due to effects of digestible AA levels and ambient temperature was different and line-specific.

Three isotopic tracers ([2,3,3-2H3]-L-serine, [2H11]-L-betaine, and [1-13C]-L-methionine) were administered by amnion injection into 18-day-old chick embryos to investigate the kinetics of methionine metabolism. The embryos utilized were from eggs collected from 34-week-old Cobb 500 broiler breeders that were fed either a control diet containing folic acid (1.25 mg/kg diet) and pyridoxine HCl (5 mg/kg diet) or diets devoid of supplemental pyridoxine or folic acid. Intermediate metabolites of methionine metabolism and polyamines were analyzed in 18-day-old chick embryos. There were no differences in hepatic [2H2] methionine or [2H3] cysteine enrichments or in physiological concentrations of sulfur amino acids for chick embryos from breeders fed the control diet and embryos from breeders fed diets containing no pyridoxine or folic acid. Supplementation of B6 or folic acid did not affect the production of methionine and cysteine in chick embryos. However, breeders fed the control diet with both folic acid and pyridoxine supplementation produced embryos with a two-fold reduction of hepatic homocysteine and increased spermine compared with embryos from breeders fed diets containing no supplemental pyridoxine or folic acid (P

This study was conducted to determine the effectiveness of air deformation on fillet surfaces to assess hardness and identify woody breast (WB) in raw fillets of broilers. Fillets (n = 120) were categorized in normal (NORM), mild (MILD) and severe (SEV) WB. All fillets were subjected to compression force (CF) analysis and pressurized air (344 kPa) was directed at the ventral surface of each fillet in the cranial region and the deformation area was measured. Fillets were cooked and sheared using Muellenet Owens Razor Shear (MORS) and blunt version of MORS (BMORS). CF increased as severity of WB increased (P

The global poultry industry has been faced with emerging broiler breast meat quality issues including conditions known as white striping (WS, white striations parallel to muscle fibers) and woody breast (WB, hardness of raw fillet). Experiments were conducted to evaluate effects of WS and WB hardness on meat quality traits in broiler breast fillets. In Exp. 1, birds were processed at approximately 9 wk of age and deboned at 4 h postmortem (PM); in Exp. 2, birds were processed at approximately 6 and 9 wk of age and deboned at 2 h PM. Fillets were categorized as: normal for both white striping and woody breast (NORM); moderate for white striping and mild for woody breast (MILD); severe for white striping and mild for woody breast (WS); severe for woody breast and moderate for white striping (WB); or severe for both white striping and woody breast (BOTH). Sarcomere length, gravimetric fragmentation index, marination uptake, cook loss, and Meullenet-Owens razor shear energy (MORSE) values on non-marinated and marinated fillets were assessed. Sarcomeres tended to be longer (P = 0.07) with increasing severity of WS and WB in both experiments and gravimetric fragmentation index did not differ (P0.05) among categories. Marinade uptake decreased (P 0.05) with increasing severity of WS and WB. Cook losses of non-marinated and marinated fillets were greatest (P 0.05) in the BOTH category. Even though MORSE values did not differ (P0.05) in non-marinated fillets, the marinated BOTH fillets had greater MORSE values (P 0.05) than other categories of fillets in Exp. 1. Non-marinated NORM fillets had greater (P 0.05) MORSE values than the other categories at 6 wk age; however, MORSE values did not differ (P0.05) among categories of marinated breasts. At 9 wk, WS and BOTH were higher (P 0.05) in MORSE compared to NORM for non-marinated fillets, but similar to NORM marinated fillets. Results suggest that severe degrees of white striping and woody breast, individually or in combination, negatively impact meat quality, especially water holding capacity attributes such as marinade uptake and cook loss.

Made available in DSpace on 2018-11-27T16:41:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-01 Two hundred and fifty Cobb-Vantress broiler breeders were used to determine the maintenance requirement and efficiency of utilization of dietary Cys, Tyr, and non-essential amino acids (AA) in a 21-day experiment. The breeders were fed crystalline amino acid diets containing graded levels of Cys or Tyr representing 0, 10, 20, 30, and 40% of their suggested requirement level with all other amino acids maintained at 40% of their suggested requirement level. To determine the non-essential AA maintenance requirement, graded levels of non-essential AA were provided by glutamic acid to represent 12, 19, 26, 33, and 40% of the ideal level of glutamic acid with all other amino acids maintained at their maintenance requirement level. The total sulfur amino acid (TSAA) and Phe + Tyr requirements were calculated by combining Cys and Tyr results, respectively, with previously determined Met and Phe, respectively. The slope of Cys, Tyr, and non-essential AA accretion regression line indicated that 29% Cys, 24% TSAA, 21% Tyr, 20% Phe + Tyr, and 9% nonessential AA of crystalline amino acids were retained. The Cys requirement for zero protein accretion was calculated to be 30.48 mg/d or 17.006 mg/kgBW(0.75)/d or 75.426 mg/kgCP/d. The TSAA requirement for zero accretion was calculated to be 132.25 mg/b/d, 71.48 mg/kgBW(0.75)/d, and 307.55 mg/kgCP/d. The Tyr requirement for zero protein accretion was calculated to be 65.907 mg/d or 37.233 mg/kgBW(0.75)/d or 175.566 mg/kgCP/d. The Phe + Tyr requirement for zero protein accretion was calculated to be 352.18 mg/b/d, 190.37 mg/kgBW(0.75)/d, and 749.33 mg/kgCP/d. The non-essential AA requirement for zero protein accretion was calculated to be 3715.194 mg/d or 2003.155 mg/kgBW(0.75)/d or 9452.954 mg/kgCP/d. Univ Arkansas, Ctr Excellence Poultry Sci, Fayetteville, AR 72701 USA Dow AgroSci LLC, Indianapolis, IN 46268 USA Univ Estadual Paulista, Coll Agr & Vet Sci, Dept Anim Sci, BR-14884900 Sao Paulo, Brazil Univ Estadual Paulista, Coll Agr & Vet Sci, Dept Anim Sci, BR-14884900 Sao Paulo, Brazil

Previously, a Saccharomyces cerevisiae fermentation product (SCFP) was demonstrated to positively alter fecal microbiota, fecal metabolites, and circulating immune cell functionality in adult dogs. The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of trained dogs subjected to an exercise challenge. All procedures were approved by the Four Rivers Kennel IACUC prior to experimentation. Thirty-six adult dogs (mean age: 7.1 y; mean BCS: 4.9) were used. Dogs were randomly assigned to control or SCFP-supplemented (250 mg/d) diets, trained, and fed for a few mo prior to exercise challenge. Fresh fecal samples were collected for the measurement of fecal characteristics, microbiota, and metabolites before and after an exercise challenge (10 mile run). Fecal microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with treatment and exercise as fixed effects, dog as random effect, and P < 0.05 considered significant. For both treatments, fecal scores and butyrate and propionate concentrations were lower and fecal pH and ammonia, isobutyrate, isovalerate, and total BCFA concentrations were higher after exercise challenge. SCFP did not affect fecal scores, pH, dry matter, or fermentative end-product concentrations after exercise challenge. Alpha-diversity or beta-diversity (unweighted PCoA plot) were not affected by SCFP before or after exercise challenge. The weighted PCoA plot, however, showed clustering of dogs before exercise and after exercise, regardless of treatment. Fecal Collinsella, Slackia, Turicibacter, Blautia, Dorea, Ruminococcus, Faecalibacterium, Catenibacterium, Clostridium (Erysipelotrichaceae family), and Eubacterium relative abundances were higher, while fecal Bacteroides, Parabacteroides, Prevotella (Prevotellaceae family), Phascolarctobacterium, Fusobacterium, Suttella and Anaerobiospirillum relative abundances were lower after exercise challenge. SCFP increased fecal Lactobacillus compared to controls. Our data demonstrate that exercise and SCFP alter fecal microbiota in dogs. Higher SCFP dosages may provide greater changes and may be of interest in future studies.

Exercise-induced muscle damage and subsequent inflammation and soreness are frequently studied topics in both human and animal trials. Gait analysis using a commercial mat system is a newer technology that identifies the temporal and spatial qualities of a subject’s gait. Gait analysis in healthy canines, especially in an exercise model, has been infrequently studied. Our objectives were to compare gait analysis metrics between exercised and non-exercised dogs, to identify which parameters were most impacted by running exercise, and to identify the ideal time to perform gait analysis post-exercise. Twenty-four Labrador retrievers were used in this trial, with 12 untrained dogs performing one 5km run, and 12 untrained dogs providing a resting comparison. All dogs were gaited using a Gait4Dogs (CIR Systems, Inc) pressure walkway system at baseline, 30min post-run, 3h post-run, and 24h post-run. For pressure measurements, no significant differences were found in resting dogs. In exercised dogs, number of activated sensors was significantly lower 30min post-run compared to baseline (p=0.05). Pressure time was significantly faster 30min post-run compared to 3h post-run (p=0.007), indicating discomfort during the walk. For spatial measurements, no significant differences were found in resting dogs. In exercised dogs, swing% was significantly lower in front limbs at 30min post-run compared to baseline (p=0.001) and in hindlimbs at 30min post-run compared to 3h post-run and 24h post-run (p=0.001), indicating reduced flexion. Stance% was significantly higher in front limbs at 30min post-run compared to all other timepoints (p=0.001) and in hindlimbs at 30min post-run compared to 3h post-run and 24h post-run (p=0.001). Stance time and step time were significantly lower at 3h post-run compared to 30min post-run and 24h post-run (p=0.001;p=0.006), indicating discomfort during the walk. In summary, untrained Labrador retrievers had a significantly affected gait primarily thirty minutes and three hours after exercise compared to resting dogs.

Over time, the need to update amino acid (AA) requirements for canines becomes increasingly important to ensure animals are healthy and free of nutritional disease. Each of the AA plays a crucial role in the metabolism and health of mammals. Of the essential AA, the total sulfur amino acids (TSAA), namely methionine (Met) and cysteine (Cys), are involved in metabolic functions such as protein metabolism, intestinal health, and urinary function. Additionally, Met can function as a precursor in the requirement of Cys. The purpose of this experiment was to use the indicator amino acid oxidation technique to determine amino acid requirements on growing Labrador Retrievers. A total of 12 dogs were subjected to 12 diets with varying levels of Met and Cys, ranging from deficient to excess. Diets were formulated to 1.6x NRC values for all indispensable amino acids. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken line model (JMP® Pro 15). Results showed that the Met and TSAA mean and population requirements were 0.78 ± 0.16 and 1.53 ± 0.21 g/1000kcal (mean ± 2SD), respectively. Knowledge gained from these studies is necessary as the petfood industry aims to deliver accurate diet formulations to the expansive canine population.

An initial study profiled non-cellulosic polysaccharide (NCP) levels in feed ingredient samples-corn, soybean meal (SBM), whole soybean, and distillers dried grains with solubles (DDGS). A separate NCP digestibility assay was performed in broilers at day 21 (grower phase) and day 42 (finisher phase) fed corn-soy based diets with and without composite enzymes (phytases, multi-carbohydrases, and proteases). Negative control (NC), NC + composite enzymes (NC+E), and positive control (PC) diets were tested. Negative control and NC + E diets were isocaloric, 3,020 kcal/kg ME at grower phase and 3,026 kcal/kg ME at finisher phase. Positive control diet was formulated to meet the Cobb standard nutrient specifications. Diets, pooled digesta, and excreta samples from all treatment diets were collected from 21- and 42-day-old birds and NCP content analyzed as soluble NCP (S-NCP) and insoluble NCP (I-NCP) fractions. Digestibility coefficient (DC) values were determined for all dietary treatments for both the feeding periods. Results from the ingredient analysis showed NCP levels of ∼7 to 10% in corn samples, ∼8 to 11% in SBM samples, ∼11 to 14% (including pectin level) in whole soybean, and ∼12 to 17% in DDGS samples, suggesting variation (P < 0.05) in NCP levels existed within ingredient samples. Digestibility assays showed that enzyme treated (NC + E) diet improved DC values at day 21 from 6 to 10 units and 6 to 9 units for ileal and total tract collection, respectively, for I-NCP fraction (P < 0.05) compared to DC values for NC or PC diets. The ileal DC values at day 42 were not different between treatment diets (∼0.6) but total tract DC values improved 9 to 11 units for broilers fed NC + E diet compared to NC or PC diets. Higher DC values for S-NCP were observed for all treatments for both feeding periods (∼0.7-ileal and ∼0.8-total tract) compared to DC values for I-NCP. Overall, the use of supplemental enzymes in corn-soy-based diets showed improvement in total NCP digestion.

Digestibility coefficients of nutrients, metabolizable energy (ME), net energy (NE) and the ratio of NE to ME (NE/ME) of 20 diets were measured in broiler chickens (1 to 21 d). Dietary nutrients were formulated to keep similar ME/nutrient ratios, except for dietary protein, fat, and fiber using corn, soybean meal, animal protein blend, barley, poultry oil and an enzyme mixture of xylanase, glucanase, and phytase. Digestibility coefficients of nutrients and ME were measured in battery cages under free-access of feed, while NE was measured in floor pens feeding 75% of recommended ME intake each day. NE for maintenance was calculated on basis of mean metabolic weight using a coefficient from a previous study and NE for gain was calculated by body protein and fat gains using dual-energy x-ray absorptiometry. Digestibility coefficients of protein and neutral detergent fiber (NDF) were curvilinearly related to dietary protein and NDF, respectively, while digestibility coefficients of fat and starch were linearly correlated to dietary fat and starch, respectively. The inclusion of enzymes increased the digestion coefficient of NDF to predict the digestibility of protein, NDF, fat, and starch. MEn/gross energy ratio averaged 72.5% and was correlated to protein, fat, NDF, and starch. ME values were accurately predicted from chemical characteristics, where best equations were obtained from digestible nutrients. Energetic efficiencies of ME were 72% (NE/MEn) and 68% (NE/ME) and varied by about 20 and 18%, respectively. Ratios of energetic efficiency were 68% for digestible carbohydrates; 86% for digestible fat; and 76% (NE/MEn) and 59% (NE/ME) for digestible protein. According to the lowest residual standard deviation the best nutrient components to predict energy were digestible nutrients for predicting ME values (41 kcal/kg); digestible protein intake, fecal organic matter, and body fat and protein for predicting heat increment values (111 kcal/kg); and combination of ME and crude nutrient for predicting NE values (140 kcal/kg).

A study was conducted to determine the effect of different feeding programs and energy intakes on the body composition of broiler breeders (BB) from 22 wk of age to 65 wk of age. Cobb 500 BB that had been reared using three growth curves: (1) the control group followed Cobb 500 guidelines (SBW) for target body weights (BW), (2) the second group target BW was 20% heavier (HBW) than the SBW group, and (3) the third group target BW was 20% lighter (LBW) than the SBW group. At 21 wk of age, pullets from each growth curve were assigned to be fed one of six treatments. Diets were formulated and allocated to provide 330, 360, 390, 420, 450, or 480 kcal ME/hen/d and 24 g protein/hen/d, at peak intake. Body composition (lean mass, fat mass, and mineral content) was measured by dual-energy x-ray absorptiometry throughout the production period. Significantly, greater (P0.05) amounts of fat mass and lower amounts of lean mass were evident at the beginning of the production period for HBW hens compared with SBW and LBW hens. Higher levels of energy intake also affected body composition. Namely, fat deposition was greatest throughout the production period in hens consuming 480 kcal/d at peak intake (P0.05). Critically, fluctuations to lean and fat mass throughout the production period are suggestive of underlying regulatory processes. Specifically, hens appears to maintain consistent lean mass throughout the production period with a coefficient of variation of12% across all birds. The results of this study provide important BB body composition information from management and nutrition studies that showed the dynamics of body composition change during the production period.

Trace mineral amino acid chelates (TMAAC) maintain integrity prior to absorption without binding to or interacting with other minerals or chelating compounds. TMAACs are essential as prosthetic groups for activating important enzymes like superoxide dismutase (SOD), which is needed to rid the body of free radicals and reactive oxygen species. A 19-day trial utilizing 20 Labrador Retrievers (10m/10f) was set up to determine the effects of TMAAC tabs on performance, recovery, and exercise induced inflammatory response. Dogs were sorted into two treatment groups: the TMAAC group received three oral tablets per day and the CON group received none. Body weights were recorded weekly and feed consumption was recorded daily. All dogs participated in an 8.05 km endurance run on Day 18, inducing exercise stress. Blood draws for serum biomarker analyses and gait analyses were performed at baseline (prior to treatment), 1-hour post-run, and 24-hours post-run. A pressure sensing computerized mat (CIR Systems, Inc) was used to evaluate lameness based on temporal spatial gait parameters. Dogs were walked on the mat at each time point to obtain three valid walks for analysis. TMAAC male dogs had similar amounts of SOD at baseline (P = 0.63) but increased 0.38 ng/ml SOD from baseline to Post-1h, while CON males had a 0.46ng/ml significant decrease in SOD (P = 0.002). Positive antioxidant trends favored TMAAC dogs across biomarkers assayed (P = 0.06). Gait lameness scores (GLS) indicated TMAAC males had unbalanced gait at baseline but recovered their normal gait after being on the treatment (P = 0.02). Stride length evaluation found that after treatment, this characteristic remained constant for TMAAC dogs but became uneven Post-24h for CON dogs (P = 0.04). Data collected from this trial indicate some significant exercise recovery improvement in working Labrador Retrievers supplemented with trace mineral amino acid chelates.