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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

Summary Corn dried distillers' grains with solubles (DDGS) are an important ingredient for poultry feeds. The efficiency of producing ethanol has improved affecting its nutrient composition; for example, improvement of the extraction of fat; the use of enzymes to degrade most of the starch could be adding more variability between DDGS suppliers. Therefore, regular analysis of DDGS is imperative. In the present study, 8 suppliers of the US ethanol industry provided samples of DDGS to perform various analysis including proximate analysis, starch, sugars, mineral analysis, AMEn, apparent ileal amino acid digestibility (AIAD), and standardized ileal amino acid digestibility (SIAD), particle size, and color. Proximate analysis was evaluated by 4 different laboratories where CP and ash showed the lowest variability compared with crude fat and crude fiber variability between laboratories. The results are provided at 88% DM, CP averaged 27.5% (25.6–29.9%), crude fat 9% (4.8–11.2%), starch 1.3% (0–6.4%). Particle size was quite variable with an average of 895 um (462–1,529 um). For the color evaluation, the CV (%) between DDGS was 9% for lightness, 14% for redness, and 10% for yellowness. The average AMEn was 2,169 (2,017–2,278 kcal/kg) (88%DM). Differences in AIAD and SIAD of amino acids are provided. Apparent ileal amino acid digestibility of lysine was 69% (65.5–71%); SIAD of lysine was 73% (70–75%); AIAD M + C was 78% (73–80%), and SIAD M + C was 81% (76–83%), the rest of essential and nonessential amino acids are presented in this article.

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.

Two meat-type broiler strains, strain A and strain B, were reared in floor pens (25 birds/pen; 45 pens/strain) for pectoralis (P) major collagen and mixed muscle protein turnover (PT) study from 0-56 D using primary breeder nutrition and husbandry guidelines. Forty broilers (n = 10/strain for collagen PT; n = 10/strain for mixed muscle PT) were selected at each sampling age at day 21, 28, 35, 42, and 56 and infused with 1-13C proline (Pro) and 15N-phenylalanine (Phe) which are used as amino acid tracers for collagen and mixed muscle PT measurements, respectively. Muscle and plasma samples were collected, and enrichments of 1-13C Pro and 15N-Phe were determined using mass spectrometry. Fractional synthesis rate (FSR) and fractional degradation rate (FDR) were measured for collagen and mixed muscle using precursor-product principle. At day 42, after separating the sampled broilers as myopathy (woody breast [WB] score > 1) and nonmyopathy (WB = 0), plasma metabolites were screened for differential 3-methyhistidine (3-MH) expression for both strains. Data were analyzed using one-way ANOVA using t test. Results showed that collagen and mixed muscle FSR and FDR in pectoralis major decreased (P < 0.05) for both strains as the broilers aged. FSR for collagen and FDR for mixed muscle were higher for strain B than those for strain A (P < 0.05). Total collagen was higher (P < 0.05) for strain B. Differentially expressed 3-MH in plasma was higher (P < 0.05) for myopathy-affected broilers indicating greater muscle degradation occurring in myopathy-affected broiler types for both strains. 3-MH Expression in plasma was higher for strain B than for strain A. The research findings showing an increased collagen content per unit muscle weight in pectoralis major in strain B (than in strain A) could be due to higher mixed muscle FDR and increased collagen FSR occurring during the grow-out period. The increased degradation of muscle fibers and probable replacement of muscle-specific protein with connective tissue, mainly collagen, was an evident pathophysiological phenomenon occurring in myopathy-affected broilers.

L‐Carnitine is critical for protection against bioaccumulation, long‐chain fatty acid transportation and energy production. Energy production becomes important as the body maintains lean mass, repairs muscles and recovers from oxidative stress. The aim was to investigate the effects of supplemented L‐carnitine on protein turnover (PT), energy expenditure (EE) and carnitine metabolism in muscle/serum of Labrador Retrievers. In a series of experiments, all dogs were fed a low‐carnitine diet and sorted into one of two groups: L‐carnitine (LC) supplemented daily with 125 mg L‐carnitine and 3.75 g sucrose or placebo (P) supplemented with 4 g sucrose daily. The experiments consisted of analyses of muscle/serum for L‐carnitine content (EXP1), a protein turnover experiment (EXP2) and analysis of substrate utilization via indirect calorimetry (EXP3). EXP1: 20 Labradors (10 M/10 F) performed a 13 week running regimen. L‐Carnitine content was analysed in the serum and biceps femoris muscle before/after a 24.1 km run. LC serum had higher total (p

SUMMARY: Novel protein feeds are needed in ecological and organic poultry production to supply natural sources of amino acids, particularly methionine. Synthetic amino acids are increasingly banned in certified organic production. Carp is an invasive fish in the United States and its harvest can help provide natural source of methionine, while reducing an undesirable population. In our previous study, we formulated a diet using extruded carp-based meal (CBM) to replace synthetic methionine in broiler diets and conducted a feeding trial to test its effect on broiler performance. For this study, birds were processed at the end of the feeding trial and evaluated for quality and sensory attributes of meat from birds fed with CBM diet. Controls were normal diet that contained methionine and the carp meal was used to replace methionine and a portion of soybean meal. Results suggest that birds fed with CBM diet did not differ from the Control in live weight, carcass weight, breast weight, ready-to-cook yield, wing yield, tenders, and thigh yields (P > 0.05). Breast meat was more light (L*) for birds from the CBM treatment compared to the Control and the pH was lower (P < 0.05). For the thigh meat, birds fed CBM diets resulted in higher protein and less fat compared to the Control (P < 0.05). In the consumer analysis, overall impression, flavor, and mouthfeel were lower for the CBM breast meat than the Control and scored lower in terms of tenderness and juiciness (P < 0.05). Interestingly, thigh meat from CBM had more omega-3 fatty acids, which has a human health benefit. The results indicate that carp-based meal hold potential as a novel protein to replace synthetic methionine in organic broiler diets.

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.

Background and Objective: Environmental temperature (ET) often changes the nutrient intake/output for layers. Changing feed formulations based on ET may need to be utilized to obtain optimum performance, shell quality and bone status. This study was conducted to investigate the effects of temperature, Ca intake, non-phytate P (NPP) intake and in vitro limestone solubility (LS) on egg-shell quality and bone status in commercial White Leghorn hens. Materials and Methods: Two 9 weeks feeding experiments were conducted with two ages of commercial White Leghorns housed in either a constant (21.1°C) thermoneutral temperature or in hot ambient temperatures (constant: 26.6°C or 32.2°C or cycling: 01:00-09:00 h at 26.7°C; 09:00-13:00 h at 29.4°C; 13:00-18:00 h at 35.0°C and 18:00-01:00 h at 29.4°C with 24 h mean of 29.7°C). In Experiment (EXP) 1, 360-130 week molted hens were housed in a constant ET at 21.1, 26.6 and 32.2°C and fed 3 levels of Ca (3.8 g, 4.9 g and 6 g/h/d), 2 levels of NPP (450 and 600 mg/h/d) while feeding 2 different LS (in vitro solubility of 34.1 and 48.4%). In EXP 2, 480-48 week old hens were housed in constant ET at 21.1°C or in cycling hot ET(with 24 h mean of 29.7°C: 01:00-09:00 h at 26.7°C; 09:00-13:00 h at 29.4°C; 13:00-18:00 h at 35.0°C and 18:00-01:00 h at 29.4°C) and fed 2 different LS (in vitro solubility of 34.1 and 48.4%) and four predicted intakes of NPP ( 250, 350, 450 and 550 mg/h/d). Results: Egg mass and shell weight per unit surface area (SWUSA) decreased with increasing ET (p

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.

Branched chain amino acids are heavily involved in protein synthesis and turnover, emphasizing the need to establish requirement for growing animals. On the other hand, threonine is vital for supporting proteins necessary for gut health. Thus, it is very important to supply branched chain amino acids and threonine in appropriate amounts to growing animals. In this experiment, the indicator amino acid oxidation (IAAO) technique was utilized to determine valine, isoleucine, leucine, and threonine requirements in six puppy Labrador Retrievers (>14wk-9mo). Puppies were subjected to diets ranging from deficient to excess, with each of the indispensable amino acids formulated at 1.6x NRC values. The control diet was fed for two days of adaptation, followed by one experimental day in which the test diet was fed. On the test day, a breath sample was collected using a using a respiration mask (Oxymax, Columbus Instruments). A priming dose of L-[1-^13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on body weight was supplied to each puppy, followed by [1-^13C]Phe doses every 30 minutes, for a four hour period. ^13CO[2] was collected after each dose and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results from IRMS were converted to atom percent excess (APE) and analyzed using a segmented line model (JMP^® Pro 16). Each of the Four Rivers mean and population requirements were as follows: 1.72 ± 0.11 g/1000 kcal ME for valine; 1.43 ± 0.24 g/1000 kcal ME for isoleucine; 2.25 ± 0.15 g/1000 kcal ME for leucine; 1.74 ± 0.16 g/1000 kcal ME for threonine (mean ± 2SD). The knowledge gained from this study is highly useful as the lean mass deposited as a puppy influences the animal throughout their lifetime.

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.

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.

A study was conducted to understand the differentially expressed genes in Pectoralis (P) major under woody breast (WB) myopathy condition in a high yielding broiler strain using RNA-sequencing at the growing (d 21) and finishing (d 42 and d 56) grow-out ages. Follow-up study was conducted to understand the in vivo triglyceride (TG) synthesis (d 49) occurring in adipogenic tissues using deuterium oxide (2H2O) as a metabolic tracer. Results indicated the top physiological systems affected in myopathy broiler were related to the musculo-skeletal system (d 21, 42, and 56) and cardiovascular system (d 42 and 56). Ubiquitin-specific proteases are expressed higher in myopathy broiler at d 21 (OTUD1) and d 42 (SACS) that potentially indicated higher degradation of muscle protein occurring at those ages. While genes related to transcription factors and muscle cell differentiation (ZNF234, BTG2) and muscle growth (IGF1) were upregulated with myopathy broiler suggesting concurrent muscle fiber regeneration. The downregulation of PYGB and MGAM genes related to carbohydrate transport and metabolism at d 42 potentially indicated nutrient-deficient state of myopathy affected fibers; whereas the nutrient-deficient physiological state of cells seemed to be counteracted by up-regulation of genes related to carbohydrate (ALDOB, GPD1L2) at d 56. There was a reduced (P < 0.05) in vivo TG synthesis in liver of the myopathy broiler (0.123 %/hr) compared to non-myopathy broiler (0.197 %/hr). The majority of TG synthesized in liver with myopathy broiler could conceivably be delivered to P. major (rather than to abdominal fat pad storage) to fulfil the increased energy need of muscle cells (via TG lipolysis and fatty acid [FA] oxidation). The increased utilization of FAs in the WB affected muscle could result in reduced secretion of FAs into blood circulation leading to sub-optimal availability of FAs for re-esterification for TG synthesis in liver. Results indicated that myopathy broiler at later age (d 56) of grow-out period were synchronously going through adaptive physiological processes of feedback responses to adverse cellular states.

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.

Two meat-type broiler lines, line A and line B were fed experimental diets from 22–42 d with objectives to determine the effects of dietary metabolizable energy (ME) levels on feed intake (FI), performance, body composition, and processing yield as affected by environmental grow-out temperatures. Two thousand fifty male chicks from line A and 2,050 male chicks from line B were reared in 90-floor pens, 45 chicks per pen utilizing primary breeder nutrition and husbandry guidelines for starter (1–10 d) and grower (11–21 d) phases. Experimental finisher diets consisted of 5 increasing levels of apparent nitrogen corrected ME (2,800, 2,925, 3,050, 3,175, and 3,300 kcal/kg set at 19.5% crude protein and 1.0% dLys at each level) to represent 80, 90, 100, 110, and 120% ME of Evonik AminoChick energy level giving 2 × 5 factorial design and were fed from 22–42 d. All other amino acid levels in diets were formulated to a fixed ratio of dLys level. There were nine replicate pens for each diet and each line. The experiment was conducted twice—once in hot season (barn averages: 77.55 ˚F and 86.04% RH) and another in cool season (barn averages: 69.91 ˚F and 63.98% RH) of the year. Results showed that FI and feed conversion ratios (FCR) decreased (P 0.9). However, there was no difference (P > 0.05) in % weights (of live weight) for wings, breast filet, tenders, or leg quarters across ME levels for both lines except % fat pad that increased (P 0.05), whereas higher BW and improved FCR were observed for line A. Line A had higher % fat mass in both seasons. In summary, performance and yield results as affected by dietary ME levels were line specific and were affected by grow-out seasons. The optimal dietary ME level for the ME range studied (2,800–3,000 kcal/kg) at a constant recommended amino acid level lies in determining the best performance and profitability indices by taking into account the grow-out production inputs and processing yield outputs.

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.

Cardiovascular disease in dogs may have minimal outward signs in the beginning stages, but early detection and intervention are vital to help affected dogs live longer and have better quality of life. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin-I are two biomarkers that show promise for detection of cardiovascular disease at a research level, but a deeper understanding is necessary to bring them into the forefront for diagnostic purposes. The aim of this research was to present values of NT-proBNP and troponin-I in healthy Labrador retrievers and in Labrador retrievers with subclinical dilated cardiomyopathy (subDCM). 55 intact Labrador retrievers (27m/28f) were selected based on good clinical health, with no prior evidence of cardiovascular disease. All dogs were maintained on the same standard kennel diet prior to testing. Each dog had plasma collected for NT-proBNP analysis (Cardiopet; Idexx) and serum collected for troponin-I analysis (Immulite; UC Davis Vet Lab). Each dog then had an echocardiogram performed by an experienced sonographer which was reviewed by a boarded veterinary cardiologist. Out of 55 adult Labrador retrievers, 46 (24m/22f) were classified as normal and 9 (3m/6f) were classified as having occult subDCM. Normal Labrador retrievers had a significantly lower mean NT-proBNP of 695 ± 432 pmol/L compared to subDCM Labrador retrievers with a mean of 1144 ± 546 pmol/L (P = 0.009). Normal Labrador retrievers had a lower mean troponin-I of 0.07 ± 0.04ng/mL compared to subDCM Labrador retrievers with a mean of 0.1 ± 0.07ng/mL, trending towards significance (P = 0.08). In summary, healthy Labrador retrievers had significantly lower NT-proBNP compared to Labrador retrievers affected with subclinical dilated cardiomyopathy.

It is well documented that companion animals are living longer and as animals age their cells undergo immuno-aging or senescence, an age associated process of deterioration. In an effort to see how aging plays a role in immune cell proliferation, twelve healthy Labrador Retrievers (6-Young, 3Male/3Female, 6-Senior, 3Male/3Female) were selected to participate in a trial to determine what effect aging might have on the proliferative rate of peripheral blood mononuclear cells (PBMC). Mean age for Senior group was 8.74yrs, Young 2.38yrs (P.< 0.0001). Peripheral blood mononuclear cells (PBMC) were isolated, counted, seeded at a density of 5x104 in 96-well MP, cultured in RPMI-1640 complete medium (5% FBS), and mitogenic stimulation via 2-fold serial dilutions of Phytolacca Americana lectin (pokeweed mitogen-PWM) ranging from 0.8 -0.025 µg/mL. Following 48hr incubation in 5% CO2/95% humidity, 100µM Bromodeoxyuridine (5-bromo-2’-deoxyuridine, BrdU; a synthetic analog nucleoside of thymidine), was added to each culture well and further incubated 24hrs to allow DNA incorporation. Cells were harvested, denatured, and BrdU incorporated in newly synthesized DNA was bound by monoclonal antibodies (anti-BrdU-POD). The immune complexes were detected by tetramethyl-benzidine (TMB), reaction stopped with 1M Sulfuric acid (H2SO4), and quantified by measuring absorbance at 450nm. Proliferation was higher in Young dogs than Senior dogs at every concentration, signifying overall statistical significance (Mean: Young-0.972, Senior-0.697±0.057 SEM, P = 0.001). Rate difference by concentration was as follows: PWM 0.00 µg/mL: Young-0.109, Senior-0.194±0.031 (P = 0.099); 0.025 µg/mL: Young-0.788, Senior-0.481±0.201 (P = 0.321); 0.05 µg/mL: Young-1.002, Senior-0.610±0.207 (P = 0.227); 0.1 µg/mL: Young-1.113, Senior-0.776±0.195 (P = 0.244); 0.2 µg/mL: Young-1.249, Senior-0.915±0.172 (P = 0.217); 0.4 µg/mL: Young-1.271, Senior-0.965±0.148 (P = 0.191); 0.8 µg/mL: Young-1.252, Senior-0.936±0.117 (P = 0.101). These results coincide with other published literature, and these data suggest age plays a critical role in immunity and proliferative ability of PBMCs in the Labrador Retriever.

Previously, a Saccharomyces cerevisiae fermentation product (SCFP) positively altered fecal microbiota, fecal metabolites, and function of circulating immune cells in adult dogs. The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs subjected to travel stress. 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/day) diets and fed for a few months prior to a travel stress challenge. Fresh fecal samples were collected for the measurement of fecal characteristics, microbiota, and metabolites before and after travel stress. Fecal microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with P < 0.05 considered statistically significant. There were no differences between treatments on fecal characteristics, metabolites, and bacterial alpha and beta diversity measures. However, fecal Turicibacter increased in dogs fed SCFP (0.8% to 1.2%, P = 0.03), but decreased in dogs fed control (1.2% to 0.7%, P = 0.03). Fecal Prevotella (5% to 7%, P = 0.004), Oscillospira (0.07% to 0.1%, P = 0.004) and Sutterella (3% to 4%, P = 0.01) increased after travel stress in dogs fed control. In contrast, fecal Clostridium (11% to 15%, P = 0.01), Faecalibacterium (6% to 8%, P = 0.003), and Allobaculum (1% to 2%, P = 0.02) increased and fecal Phascolarctobacterium (1.4% to 1.1%, P = 0.001) decreased after travel stress in dogs fed SCFP. Our data demonstrate that both travel stress and SCFP alter fecal microbiota in dogs.

Despite consumer interest in senior pet care, little is known about the effect of changing crude protein (CP) levels on the lysine (Lys) requirements in young and senior dogs. Feeding crude protein in excess can lead to long-term health problems. Moreover, changing the CP content of the diet can lead differences in Lys requirements. Two experiments were conducted to determine the Lys requirements in adult and senior Labrador Retrievers through the indicator amino acid oxidation technique. Six young (< 1.5 yrs) and six old (>8 yrs) dogs were allocated to two trials (6 dogs/exp) to determine the effects of feeding 13 and 18% CP on the Lys requirement. All 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 subject’s body weight 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). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken-line model of best fit (JMP® Pro 15). Oxidation results showed that for a 13% CP diet, the Lys mean and population safe requirements (mean±2SD) were 1.56±0.25 and 0.81±0.37 g/1000kcal for adult and senior dogs, respectively. For the 18% CP diet, adult and senior dog mean and population safe requirements were 1.36±0.18 and 0.86±0.07 g/1000kcal accordingly. The results suggest that as dogs age, the lowered lean mass requires less AA nitrogen and Lys to maintain body tissues.

Exercise can cause microtrauma in the tissue and joints of dogs, resulting in a cycle of inflammation and discomfort even in healthy dogs. The aim of this trial was to evaluate the effect of undenatured type II collagen supplemented on inflammation and cartilage degeneration after exercise in untrained, healthy dogs. In this experiment, 40 healthy Labrador retrievers (20m/20f; Range-5-12yrs; Avg-8yrs) were sorted into two groups: undenatured type II collagen group receiving 40mg UC-II® (10mg Collagen Type II/Min. 3% Undenatured Type II Collagen; Lonza Consumer Health, Inc.) and placebo (P) group receiving 40mg maltodextrin daily by capsule. After 2wks supplement loading, all dogs performed a 4.66 ± 0.34km endurance run. Blood was collected at baseline, 1h pre-run, and 24h post-run for hematology/biomarkers including interleukin-6 (IL-6) as an inflammatory marker and cartilage oligomeric matrix protein (COMP) as a cartilage degeneration marker. Undenatured type II collagen supplemented dogs had significantly lower IL-6 vs P at post-run (p< 0.01), as well as significant decreases from pre to post-run (P = 0.03), vs P with no significant change (P = 0.16). COMP was significantly lower in undenatured type II collagen supplemented dogs at 24h post-run compared to pre-run (P = 0.02), with P dogs having no significant differences between timepoints (P = 0.24). At both 1h pre- and 24h post-run undenatured type II collagen supplemented dogs had no significant increases in neutrophil:lymphocyte ratio (NLR; inflammatory marker), but P dogs had significantly higher NLR compared to baseline (P = 0.01). NLR was also significantly lower in undenatured type II collagen supplemented dogs compared to P dogs at pre-run (P < 0.01). Undenatured type II collagen supplemented dogs showed significantly lower white blood cell counts after supplementation compared to P dogs (P < 0.05) (Table 1). In summary, untrained Labrador retrievers supplemented with undenatured type II collagen had decreased inflammation and cartilage degeneration compared to non-supplemented dogs after exercise.

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.

Grain-free diets tend to have greater inclusions of pulses in contrast to grain-based diets. In 2018, the Food and Drug Administration (FDA) released a statement that grain-free diets may be related to the development of canine dilated cardiomyopathy (DCM). However, all dog foods met regulatory minimums for nutrient inclusion recommended by the Association of American Feed Controls Official. In some FDA case reports, but not all, dogs diagnosed with DCM also had low concentrations of plasma or whole blood taurine; thus, we hypothesized that feeding these diets will result in reduced taurine status from baseline measures. The objective of this study was to determine the effects of feeding a grain-free diet to large-breed dogs on taurine status and overall health. Eight Labrador Retrievers (four males and four females; Four Rivers Kennel, MO) were individually housed and fed a commercial complete and balanced grain-free diet (Acana Pork and Squash formula; APS) for 26 wk. Fasted blood samples were collected prior to the start of the trial (baseline; week 0) and at weeks 13 and 26 for analyses of blood chemistry, hematology, plasma amino acids, and whole blood taurine. Urine was collected by free catch at weeks 0 and 26 for taurine and creatinine analyses. Fresh fecal samples were collected at weeks 0 and 26 for bile acid analyses. Data were analyzed using the GLIMMIX procedure with repeated measures in SAS (v. 9.4). Plasma His, Met, Trp, and taurine and whole blood taurine concentrations increased over the course of the study (P < 0.05). Urinary taurine to creatinine ratio was not affected by diet (P > 0.05). Fecal bile acid excretion increased after 26 wk of feeding APS to dogs. Despite the higher fecal excretion of bile acids, plasma and whole blood taurine increased over the 26-wk feeding study. These data suggest that feeding APS, a grain-free diet, over a 26-wk period improved taurine status in Labrador Retrievers and is not the basis for the incidence of DCM for dogs fed APS. Other factors that may contribute to the etiology of DCM should be explored.

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.

Selection for quantitative traits in meat broilers such as breast yield and growth rate exert physiological pressure leading to ante mortem histological and biochemical alterations in muscle tissues. The poultry industry has recently witnessed a myopathy condition affecting Pectoralis major (breast muscle) of broilers, called woody breast (WB), an etiology still unclear to scientific community. A study was conducted to characterize the WB myopathy in a meat broiler line at its finishing phase (d 41) in terms of heat production (HP), microbiota and plasma metabolites. Two treatment groups were studied—WB affected (myopathy) and normal (non-myopathy) broiler; n = 20 in each group. Indirect calorimetry was utilized for HP measurement. Furthermore, body composition (BC) analysis was also performed using dual-energy x-ray absorptiometry (DEXA). Microbiota in ileal digesta was studied with PCR amplified 16s rRNA gene. LC-MS targeted metabolomics was performed to understand differential expression of plasma metabolites. Results showed that there was difference in fasting HP (P < 0.05) between these two treatment groups, with non-myopathy broiler producing more heat which was indicative of higher body protein content validated by higher protein: fat ratio by BC results. Less protein content in myopathy bird could be due to probable higher mixed muscle degradation occurring in lean tissue as marked by elevated 3-methylhistidine expression in plasma. Microbiota results showed unclassified Lactobacillus as predominant genus with higher abundance occurring in myopathy group; whereas at species level, L. acidipiscis was predominant bacteria for non-myopathy broiler. Differentially significant metabolites (P < 0.05) identified from plasma metabolome between these two treatment groups were homocysteine, cyclic GMP, trimethylamine N-oxide (TMAO), tyramine, carnitine, and acetylcarnitine, which were all associated to cardiovascular system. The findings suggest that more research in meat broilers could be opted toward delivering reduced vascularity issues to alleviate this myopathy condition.

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.

Twenty-four-week-old white Leghorn layers were inoculated subcutaneously with a killed Newcastle disease-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. Twenty-eight weeks after vaccination, the birds were challenged intraocularly with the Arkansas strain of infectious bronchitis virus (AIBV) to determine the effects of heterologous virus exposure on egg production, egg quality and serum antibody response of the birds. The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers. Eggs laid by the unchallenged groups weighed significantly more (P less than 0.005) than those laid by the challenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the AIBV-challenged hens was significantly (P less than 0.005) inferior to those from the unchallenged hens. In addition, the AIBV-challenged hens laid more soft-shell, misshapen and small eggs than the unchallenged hens. The Arkansas serum haemagglutination inhibition (AIBV-HI) titres of AIBV challenged birds increased up to four weeks after challenge. The corresponding MIBV haemagglutination-inhibition (MIBV-HI) titres decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to heterologous AIBV.

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.