This study explored whether trace mineral source (Zn, Mn, Cu, Fe, and Se) in a complete and balanced diet impacts gait and inflammation in Labrador Retrievers undergoing a 9-wk exercise regimen. Forty healthy, adult dogs, averaging 3 yr of age, were assigned to diets containing ether inorganic minerals (ING, n = 20) or amino acid complexed minerals (TMC, n = 20). After a 2-wk dietary acclimation, dogs began a progressively demanding exercise regimen, ending with an 8 km run. Fecal scores and food intake were recorded daily, while body weights and body condition scores were recorded weekly. Skin and coat condition were assessed at baseline, mid-study, and study end. Mobility and pain were evaluated before and after the first and last run using the Liverpool Osteoarthritis in Dogs (LOAD) and Canine Brief Pain Inventory (CBPI) questionnaires. Gait was assessed using the Gait4Dogs walkway system and the FRK Total Gait Inflammation Index Score. Both groups experienced a slight reduction in body weights (P < 0.01) and body condition scores (P < 0.01), likely due to the added energy expenditure of exercise. Skin and coat condition did not differ between the diets (P ≤ 0.15). The LOAD questionnaire tended to reveal perceptions of improved mobility after exercise (P ≤ 0.07), and a perceived improvement in the quality of life for TMC dogs after the final run was detected by the CBPI questionnaire (P < 0.01). Gait analysis revealed better left:right (L:R) symmetry ratios for step time (P = 0.01) in TMC fed dogs. Dogs from ING group had better cycle time L:R ratio (P = 0.03), though ratios for both groups were extremely close to 1:1. A treatment × time interaction for mean pressure L:R ratio revealed TMC dogs had a better ratio after the final run compared to ING dogs (P = 0.02), suggesting differences in how the two mineral sources influenced gait dynamics during the exercise regimen. Blood samples collected at 1, 6, and 24 h after the first and last runs revealed changes in several cytokines and chemokines, but only monocyte chemoattractant protein-1 (MCP-1) was influenced by a treatment × time interaction (P < 0.01). Circulating MCP-1 increased after the final exercise in dogs fed TMC but not in those fed ING. Overall, the results suggest that amino acid complexed minerals may offer advantages in perceived mobility, some gait parameters, and inflammatory responses during a sustained exercise regimen compared to inorganic minerals.

This study explored the effects of Bifidobacterium animalis subspecies lactis CECT 8145 (B. animalis CECT 8145)-in both live probiotic and heat-treated postbiotic form-on metabolic health and digestion in male and female Labrador Retrievers during weight gain and loss. The study consisted of two, seven-week phases: weight gain (200% maintenance energy intake; Phase (1) and weight loss (100% maintenance energy requirement for ideal weight; Phase (2), separated by a 2-week washout period. In each phase, forty-five adult Labrador Retrievers (1.6-12.5 years) were randomly assigned to daily supplementation with live B. animalis CECT 8145 probiotic (PRO, n = 15), heat-treated B. animalis CECT 8145 postbiotic (POST, n = 15), or placebo control (CON, n = 15). Body weight, body condition score, fecal quality and food consumption were monitored throughout the study, and body composition, fecal, and blood samples were analyzed at the beginning and end of each phase. Digestibility was evaluated at the end of each phase. Post-prandial glucose responses were affected by intervention during weight loss, with a 6% reduction in the area under the curve (AUC) in POST compared to CON dogs (p = 0.035). Glucagon was decreased in females supplemented with POST (p = 0.0014), while POST males showed increased glucagon-like peptide-1 (GLP-1) compared to CON (p = 0.016) during weight gain. Serum GGT levels decreased, within the normal reference range, in POST compared to CON dogs during weight gain (post hoc p = 0.041). Fecal isovalerate was also reduced and fat digestibility increased (p = 0.026) in POST compared to CON (p = 0.018) during weight gain. There was a significant association between the group and gastric inhibitory polypeptide (GIP), with a decrease in GIP in POST over time (p = 0.030), and glucagon tended to be decreased in POST compared to CON (p = 0.073). Overall, these findings suggest supplementation with postbiotic B. animalis CECT 8145 may improve certain markers of Labrador retrievers' metabolic health.

This study aimed to characterize the development of the immune system from puppyhood to adulthood in Labrador retrievers. Monthly blood samples were collected from 21 puppies (11M/10F) from 1 month to 1 year of age. For flow cytometry, EDTA whole blood was stained with a multi-color panel including LIVE/DEAD lime viability stain, anti-canine CD4 antibody conjugated to super bright 600, anti-canine CD8 antibody conjugated to super bright 702, anti-canine CD3 antibody conjugated to FITC, anti-canine CD21 antibody conjugated to r-PE, anti-canine CD5 antibody conjugated to PerCP-eFluor 710, and super bright staining buffer. Samples were then lysed and analyzed on an Attune NxT flow cytometer. Gates were determined according to unstained samples, and data was recorded as the percentage of lymphocytes, with the exception of CD4+ and CD8+ cells which were recorded as the percent of CD3+ cells. Plasma samples were utilized for D2Dx analysis at 12, 24, 36, and 50 weeks of age. Data was analyzed in SAS using a repeated measures mixed model with fixed effects of age, sex, and age*sex with dog as the repeated subject, and visualized in JMP. As expected, there were significant effects of age, sex, and age*sex on weight (P ≤ 0.003), with puppies growing over the source of the study, and males on average weighing more than females. There were significant age and sex effects (P ≤ 0.024) for the percentage of CD3+ T cells, which increased throughout the study and which was higher in females. There was an age effect (P < 0.001) for the percentage of CD21+ B cells which decreased as the subjects aged. There were age and sex effects (P ≤ 0.043) for CD5dim cells, tentatively identified as natural killer cells, with levels decreasing over time, and males on average having lower levels than females. The percentage of CD3+CD4+ T cells had significant effects of age and age*sex (P ≤ 0.044), with percentages increasing over time. The percentage of CD3+CD8+ T cells had significant age and sex effects (P ≤ 0.022) with percentages decreasing as the subjects aged, and males having overall lower percentages compared to females. The ratio between CD3+CD4+ and CD3+CD8+ cells had a significant age effect (P < 0.001), but unexpectedly increased considerably over the course of the study. D2Dx scores, a measure of non-cellular humoral immunity, increased significantly between 12, 24, and 36 weeks (P < 0.001), but remained stable between week 36 and the end of the study. Overall, these findings provide valuable insights for researchers and clinicians regarding immune system maturation in Labrador retrievers.

The pet food market now offers a wide range of diets, with fresh-frozen options gaining popularity for their high-quality ingredients and digestibility. While research on their long-term benefits is still emerging, they are widely valued for their freshness and nutritional quality. This ongoing study with 16 dogs is evaluating how a commercially available fresh-frozen diet (FF) compares to a commercial dry extruded kibble (KB) in terms of overall health, fecal parameters, and activity levels. Adult dogs were randomly assigned to either diet and fed at maintenance levels. Study endpoints include fresh fecal sampling at the beginning, middle, and end to measure moisture and pH. Fecal consistency scores and food intake were recorded daily, while body weight and body condition scores (BCS) were tracked weekly. Total activity levels were assessed monthly using accelerometer-equipped collars. Fecal microbiome profiles were assessed at baseline and after one month. Data collected through week 12 have been analyzed using a repeated measures mixed model. By day 91, CBC and chemistry values remained within normal reference ranges. Body weights and BCS did not differ by treatment, time, or treatment × time interaction (P ≥ 0.11). Fecal quality scores were significantly greater in the FF diet compared to KB (P < 0.01), but there were no interactions by week (P = 0.13). Analysis of the first 10 days of the study (diet transition period) revealed a significant treatment × time interaction (P < 0.01), with FF fecal scores surpassing KB by day 8. Fecal moisture and pH were not affected by treatment, time, or treatment × time interaction after one and 3 months, respectively (P ≥ 0.13). Daily activity (total, inside, or outside) was not affected by treatment or treatment × time interaction (P ≥ 0.31). Inside activity increased in the second month, as they were kept inside for the majority of the day due to inclement weather (P < 0.01). After one month, the microbiomes of both groups diverged, indicating a dietary impact, but no clear evidence favored one diet over the other yet. The fresh-frozen diet tested here generated rapid and sustained improvements in fecal consistency, a desirable trait for many pet owners.

This study determined the sensitivity of productive energy (PE; Arkansas Net Energy) to performance and body composition and developed predictive models based on PE. Chicks (2,148 day-old ones) were placed in 96 pens and assigned to one of 12 dietary treatments, including varying concentrations of total digestible amino acids (TDAA), digestible CP (dCP), digestible fat (dFat), digestible starch, and non-starch polysaccharides (NSP). Eight replications per treatment, one per block, were used, being the block consecutive groups of birds weekly starting the seven-day experimental period. In each block, birds were control fed to meet similar ME intake, placed in calorimetry chambers to determine fed (HP) and fasting heat production (FHP), and scanned (Dual-Energy X-Ray Absorptiometry) to determine protein accretion (PAC) and energy gain. N-corrected apparent metabolizable energy (AMEn) and digestible nutrients were determined. Net energy for gain (NEg; kcal/kg), net energy for maintenance (NEm; kcal/kg; NEm = FHP), heat increment (HI; HI = HP - FHP), classic net energy (CNE; CNE = AMEn - HI; kcal/kg), PE (kcal/kg), and associated ratios were calculated. BW gain (BWG) and feed conversion ratio (FCR) were recorded. ANOVA and multiple comparisons were performed. Mixed models were used to build and validate models predicting BWG, FCR, and PAC based on digestible nutrients or PE. Treatments influenced (P < 0.05) NEg, NEm, PE, CNE, PE/AMEn, but not HI or CNE/AMEn. The treatments affected the efficiencies of AMEn or CNE for BWG or PAC (P < 0.05) but not PE ones. TDAA, dCP, and dFat favored BWG and FCR, but NSP affected FCR negatively (P < 0.05). TDAA and dCP favored PAC (P < 0.01). No influence of AMEn and CNE was observed on BWG, FCR, or PAC (P > 0.05), but CNE correlated with fat gain (P < 0.03). Models to predict BWG, FCR, and PAC based on PE were developed (R2 > 0.86; P < 0.02). In conclusion, PE was shown to be an energy system able to predict broiler performance.

This study assessed the sensitivity of Productive Energy (PE) to breast meat production, feed efficiency, and broiler economics, developed models for processing traits and economics, and examined economics dynamics. The experimental design involved 96 pens, 12 per block and eight blocks, with each pen within block receiving one of 12 dietary treatments for one week. Treatment diets, varying in amino acid concentrations, starch, and energy densities, were control-fed. The weights of processing body parts and net energy for gain (NEg) were determined with Dual-Energy X-Ray Absorptiometry, and fed heat production, fasting heat production (FHP), and net energy for maintenance (NEm) with calorimetry chambers. N-corrected apparent metabolizable energy (AMEn) was determined. PE was calculated as NEg + NEm, and classic net energy (CNE) as AMEn – heat increment (heat increment = fed heat production – FHP). Feed, protein, and energy efficiencies, and economic parameters (market value gain, MVG; gross profit gain, GPG; cents/bird per day) were calculated. Mixed models predicted the growth rate of processing parts and economic traits, and non-linear models characterized economic dynamics as the birds aged. AMEn (P < 0.04) and CNE (P < 0.02) efficiencies varied across treatments, but PE efficiency remained stable (P ≥ 0.07). PE was 2.0 and 2.7 times more sensitive (P < 0.05) than CNE to changes in breast meat gain and feed efficiency, respectively. PE, but not AMEn or CNE influenced processing and economic traits (P < 0.05), and models predicting these characteristics based on PE showed high precision (R2 > 0.97). Amino acid calories supported MVG and GPG better than those from other nutrients (P < 0.01), and PE influenced the age at maximum GPG (P = 0.01). In conclusion, PE outperformed AMEn and CNE in predicting meat production and economic traits, offering a more sensitive and precise tool for broiler diet optimization.

Weaning is psychologically and physiologically stressful. The psychological impact has been shown to increase the physiological stress response, alter immune function, and impact intestinal morphology and integrity. These physiological changes may create health challenges and diarrhea that may have lasting impacts throughout the lifespan. As a result, the use of supplements by puppy pet parents is on the rise to help combat gastrointestinal distress. PROFORMIX|PET (Probiotech International Inc.), a proprietary blend of tributyrin and polyphenols, has been shown to reduce inflammation post-exercise in dogs. Therefore, the objective of the current study was to evaluate gastrointestinal, metabolic, and immune markers in puppies. Twenty Labrador Retriever puppies (16-18 weeks; 2 litters; BWT:15.6±1.38kg) were blocked by litter, sex, and body weight and allocated to two treatments for the 30-day trial: Control- PureVitaTM grain-free turkey and sweet potato for all life stages (Nutrisource®, KLN Family Brands) fed to manufacturer’s recommendations or Treatment- Control plus 500mg PROFORMIX|PET per day. Puppies were blocked by litter, sex, age and weight. Physical wellness parameters were examined throughout the trial including body weight, stool quality and a clinical assessment. Immune, metabolic, and gastrointestinal health parameters were assessed at day 0 and 30. Statistical analysis was performed in SASv9.3 with a PROC MIXED and repeated measures. In cases where both a time and treatment main effect were found significant, contrasts were performed to compare simple effect differences of time within treatment. There was no impact (P>0.05) of treatment*time, treatment or time on stool scores and clinical assessments; all puppies were clinically healthy. Body weight increased (P< 0.0001) with time in both treatments (BWT d30: Control:20.6; Treatment:20.8±0.34kg). Although treatment*time was not significant, there was an impact of treatment (P=0.0003) and time (P=0.002) on CRP. When the time effect was compared within treatment, there was a more significant decline (-66%; P=0.0009) compared to control (-52%; P=0.06) from d0 to 30. Insulin was not affected by treatment*time (P=0.44) or treatment (P=0.26) but declined with time (P=0.04) in both groups. However, there was a treatment*time effect (P=0.03) on glucose with an increase at day 30 in control puppies (105.1±1.0mg/dL) and a decrease in treatment puppies (101.1±1.0mg/dL). This may indicate that PROFORMIX|PET has an impact on insulin efficiency, but more research is warranted. Fecal a1-PI, a marker of intestinal integrity, decreased with time (P< 0.0001) as expected with aging; however, there was a greater decline (-56%, P< 0.0001) in treatment puppies compared to control puppies (-46%, P =0.04) when the time effect was evaluated within treatment. There was no effect of treatment*time (P=0.44) or treatment (P=0.66) on fecal a1-PI. This initial evaluation of PROFORMIX|PET in puppies demonstrated positive impacts on puppy wellness. More research is warranted to confirm these initial findings.

Complete uncoated extruded kibble was coated with a premium chicken fat spiked with 0%, 5%, 10%, 15%, or 20% free fatty acids (Oleic acid, Millipore Sigma. Burlington, MA), and 3% liquid chicken-based natural flavor. Kibbles were then utilized in oral palatability (20 dogs, 10M/10F), aromatic palatability (20 dogs, 10M/10F), and apparent total tract digestibility (36 dogs, 18M/18F). Kibble odors were analyzed by flash gas chromatography electronic nose (AlphaMOS, Toulouse, France), and SPME GC/q-TOF (MUMC, Columbia, MO). In the aromatic palatability trials, there were no significant differences in first approach (P ≥ 0.21), percent interaction time (P ≥ 0.16), or interaction ratio (P ≥ 0.94). In the oral palatability trials, there were no significant differences in first approach (P ≥ 0.26), first bite (P ≥ 0.50), percent consumed (P ≥ 0.15), or intake ratio (P ≥ 0.59). There was no significant difference in protein, carbohydrate, or dry matter digestibility (P ≥ 0.06), and no significant difference in fat digestibility between coated diets by Tukey's post hoc (P ≥ 0.09). Principle component analysis of e-nose peaks showed minimal odor changes between samples (DI = -3). Volatile analysis identified 16 compounds correlated with oleic acid percentage (r 2 ≥ 0.50). Kibble coated with chicken fat containing up to 20% oleic acid did not negatively impact odor profile or palatability in Labrador retrievers.

With aging comes changes in gait and mobility in our companion animals. While aspects of these mobility changes have been quantified in humans, less have been identified in dogs. The aim of this retrospective data analysis was to identify age-related gait changes in Labrador Retrievers. Data collected in March of 2018 was available on 65 dogs, of which 34 had data collected again in August of 2024 and were at that time without known mobility issues based on kennel records. Of those 34 dogs, 16 (8 males, 8 females) had reached at least 10 years of age and were used in the final data analysis. Average age at the first data collection was 5.5 years old, and after the 6 year span average age increased to 11.9 years and body weights at this time averaged 31.8 ± 3.18 kg. Gait was analyzed using the Gait4Dogs system which measures spatial, temporal, and pressure variables for each limb. For each variable, the sum of the front limb or left limb values were divided by the sum of the hind limb or right limb values to generate the front:hind (H:R) or left:right (L:R) ratios, respectively. The average value for each gait variable was also calculated. Data were analyzed in SAS using a repeated measures mixed model with fixed effects of time. Age in 2018 was included as a covariate and type 1 sum of squares was performed. Sex was included as a random effect and dog as the repeated subject. We observed significant decreases in cadence, average step length, average stride length, and average swing percentage of cycle (P ≤ 0.05). Conversely, average step time, cycle time, swing time, stance percentage of cycle, and stance time all increased as dogs aged (P ≤ 0.05). Front:hind ratios for step time, cycle time, swing percentage of cycle, and swing time all decreased over time (P ≤ 0.01), while stance percentage of cycle and stance time F:H ratios increased (P ≤ 0.01). Overall, we observed that as Labrador Retrievers aged, they developed slower gaits with reduced step and stride lengths and a shift towards spending more time in the stance phase.

This study sought to validate the D2Dx rapid immunity test in canines and investigate the age-related changes in the humoral immune system of healthy large breed dogs. Blood plasma with EDTA anticoagulant was collected from healthy Labrador Retrievers (n = 80) housed at Four Rivers Kennel under IACUC protocol FRK-56. Age groups were defined as follows: puppy 0-1.5 yr, adults 1.5-7 yr, senior 7-10, and geriatric 10-14. Immunity biomarkers including c-reactive protein (CRP), interleukin 4 (IL-4), interferon gamma (IFN-γ), complement protein 3 (C3), and immunoglobulin G (IgG) were determined through canine specific enzyme-linked immunosorbent assay (ELISA) kits. The nanoparticle based D2Dx test, which evaluates the cumulative humoral immune response, was also performed. Data were analyzed using a one-way ANOVA between age groups, with a Tukey’s post hoc, and correlations between variables were evaluated through multivariate analysis. The D2Dx score was correlated with body weight, age, IgG, and C3 validating that the test was able to adequately measure the humoral immunity in canines (r ≥ 0.49). D2Dx score was significantly different between age groups (P < 0.01) with puppies having significantly reduced scores compared with all other groups (P < 0.01). C3 was significantly different between age groups (P < 0.01), with puppies significantly less than other life stages (P ≤ 0.03). The C3 of adults averaged significantly greater than seniors and trended greater than geriatric subjects (P ≤ 0.01, 0.07). IgG between ages was also significantly different, with puppies significantly less than other age groups (P < 0.01). There was no significant difference between age groups for IFN-γ, IL-4 ratio, IFN-γ, IL-4, or CRP (P ≥ 0.18). This study showed that the D2Dx Rapid Immunity Test is able to detect changes to humoral immunity in canines. Beyond evaluating the effectiveness of the D2Dx test, this study also provides important information about the under researched topic of canine humoral immunity development and senescence in a robust, healthy cohort of large breed dogs.

Abstract Age-appropriate diets that meet the unique nutritional needs of aging are in greater demand as senior dogs represent an increasing percentage of the pet population. Studies targeting the specific amino acid requirements of the aging canine are important because they may inform dietary formulations for this specific life stage. In this study, the indicator amino acid oxidation (IAAO) technique was used to determine the minimum requirements for isoleucine (Iso) in young adult and senior Labrador retrievers. After 2-d adaptation to Iso-adequate basal diet (Iso = 0.608% dry matter), dogs underwent individual IAOO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of isoleucine ranging from deficient to sufficient (final Iso content in experimental diets were 0.244, 0.285, 0.326, 0.532, 0.57 and 0.608% dry matter). Test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was supplied (a bolus L-[1-13C] phenylalanine based on body weight was first given, followed by [1-13C] Phe doses every 30 min spanning a 4 h period), and breath samples were collected via respiration mask every 30 min. CO2 production was determined via indirect calorimetry and production of 13CO2 at each dose was measured by enrichment of 13C in breath samples via isotope ratio mass spectrometry (IRMS). Results for IRMS data were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for isoleucine were 898 ± 71 mg/1,000 kcal ME (mean ± 2 SD) for young adults and 885 ± 91 mg/1,000 kcal ME (mean ± 2 SD) in senior dogs, which is slightly greater than the National Research Council’s minimum requirement. As the pet food industry offers more specialized diets for aging canines, updating the amino acid requirements for such animals is increasingly important.

Previous studies with broiler breeders indicate a P retention threshold when fed daily dietary levels of non-phytate P (NPP) exceeding 320 mg. Fibroblast growth factor 23 (FGF23) is a hormone secreted by osteocytes which modulates P retention and could be the biological agent which controls the P threshold in breeders. To evaluate the relationship between FGF23 and the P retention threshold, a 4-wk study with 32-wk old breeders was conducted with 6 dietary treatments with daily NPP intake of 216 to 576 mg/d/h with increments of 80 mg/kg diet. The goals were 1) to elucidate how plasma FGF23 corresponds with the P retention threshold in broiler breeders and 2) to determine the amount of P for optimal egg production and bone health. Results showed that between daily 288 mg and 360 mg dietary NPP intake, P retention decreased from 33% to 26% but FGF23 levels increased from 130 pg/mL to 220 pg/mL with increasing NPP. The elevation of plasma FGF23 between the range of 288 mg to 360 mg dietary NPP/d intake suggests that FGF23 is related to the P retention threshold and may be the major hormone for regulating physiological P levels when intake of daily dietary P levels are increased above 288 mg NPP.

This study examined the effects of varying protein sources on apparent total tract digestibility, inflammatory markers, and fecal microbiota in Labrador Retrievers with historically poor stool quality. Thirty dogs (15 male, 15 female; aged 0.93 to 11.7 yr) with stool quality scores <= 2.5 on a 5-point scale (1 representing liquid stool and 5 representing firm stool) were randomly assigned to 1 of 3 nutritionally complete diets with differing protein sources and similar macronutrient profiles: 1) chicken meal (n = 10); 2) 10% brewer's yeast (n = 10); or 3) 10% torula yeast (n = 10). Another 10 dogs (five male, five female) with normal stool quality (scores ranging from 3 to 4) received diet 1 and served as negative control (NC). All dogs were fed diet 1 for 7 days, then provided their assigned treatment diets from days 7 to 37. Daily stool scores and weekly body weights were recorded. On days 7, 21, and 36, blood serum was analyzed for c-reactive protein (CRP), and feces for calgranulin C (S100A12), alpha(1)-proteinase inhibitor (alpha(1)-PI), calprotectin, and microbiota dysbiosis index. Apparent total tract digestibility was assessed using the indicator method with 2 g titanium dioxide administered via oral capsules. Stool scores were greater in NC (P < 0.01) as designed but not affected by treatment x time interaction (P = 0.64). Body weight was greater (P = 0.01) and CRP lower (P < 0.01) in NC dogs. Dry matter and nitrogen-free extract digestibility did not differ among groups (P >= 0.14). Negative controls had greater fat digestibility compared to BY (94.64 +/- 1.33% vs. 91.65 +/- 1.25%; P = 0.02). The overall effect of treatment was significant for protein digestibility (P = 0.03), but there were no differences in individual post hoc comparisons (P >= 0.07). Treatment did not affect S100A12 or alpha(1)-PI (P >= 0.44). Calprotectin decreased at a greater rate over time in TY (P < 0.01). The dysbiosis index score for BY and TY fluctuated less over time (P = 0.01). Blautia (P = 0.03) and Clostridium hiranonis (P = 0.05) abundances were reduced in BY and TY. Dogs with chronically poor stool quality experienced reduced body weights and increased serum CRP, but TY numerically increased protein digestibility, altered the microbiome, and reduced fecal calprotectin. Torula yeast is a suitable alternative protein source in extruded canine diets, but further research is needed to understand the long-term potential for improving the plane of nutrition and modulating gut health.

Complete uncoated extruded kibble was coated with 5% by weight premium poultry fat (5,000 ppm Naturox, 0.57% FFA; Tyson, Springdale, AR) spiked with 0, 5, 10, 15, or 20 percent free fatty acids (Oleic acid, Millipore Sigma. Burlington, MA), and 3% liquid chicken-based palatant (Tyson, Springdale, AR). Kibbles were then utilized in oral palatability (n = 20 dogs; 10 male, 10 female), aromatic palatability (n = 20 dogs; 10 male, 10 female), and apparent total tract digestibility (ATTG; n = 36 dogs; 18 male, 18 female). Kibble odors were by ultra-fast gas chromatography e-nose (AlphaMOS, Toulouse, France), and SPME GC-MS (MUMC, Columbia, MO). In the aromatic palatability trials, there were no significant differences in first approach (P ≥ 0.21), percent interaction time (P ≥ 0.16), or interaction ratio (P ≥ 0.94). In the oral palatability trials, there were no significant differences in first approach (P ≥ 0.26), first bite (P ≥ 0.50), percent consumed (P ≥ 0.15), or intake ratio (P ≥ 0.59). There was a significant increase in fat digestibility among diets coated with 20% FFA compared with the uncoated diet (P = 0.02), with intermediate diets showing a slight numerical increase but no significant difference. However, there was no significant difference in protein, carbohydrate, or dry matter digestibility (P ≥ 0.06). Principle component analysis of e-nose peaks showed minimal odor changes between samples (DI = -3). SPME GC-MS analysis identified 16 compounds correlated with FFA percentage (r2 ≥ 0.50). When used to coat kibble, poultry fat with up to 20% FFA did not appear to negatively impact palatability or overall odor profile, though it did modify specific volatile compounds.

Eggshell breakage and broiler bone disorders are major problems for the breeder and broiler industries which are linked to mineral metabolism and animal genetics. The purpose of this work was to discover the link between individual animal phenotypic differences in mineral metabolism against concentrations of novel plasma biomarkers including tartrate resistant acid phosphatase (TRAP) and bone alkaline phosphatase (BAP). A subset of hens were selected from a flock of Cobb 500 breeders with the best or worst eggshell quality based upon dual energy x-ray absorptiometry (DEXA) and specific gravity (SG). Breeders were defined as having good eggshell quality (SG ≥ 1.080), or poor eggshell quality (SG < 1.080). Progeny hatched from breeders with good or poor eggshell quality were reared to 2 week of age and blood and bone samples were obtained after euthanasia. In both breeders and progeny, plasma concentrations of BAP and TRAP were measured, and bone mineral density was evaluated by DEXA. Results showed that breeders selected for eggshell quality had significantly different plasma concentrations of BAP (Good = 326.5 pg/mL, Poor = 253.2 pg/mL), and TRAP activity (Good = 2203 U, Poor = 4985 U). Breeders selected for eggshell quality produced progeny with different bone breaking strength (Good = 1.61 kg/mm, Poor = 1.47 kg/mm), tibia ash (Good = 45.9%, Poor = 42.2%), plasma BAP (Good = 372.3 pg/mL, Poor = 312.4 pg/mL), and lower plasma TRAP activity (Good = 18010 U, Poor = 23590 U). These data suggest that there is a strong correlation between the eggshell quality of breeders, performance and bone strength of progeny, and plasma of concentrations of BAP and TRAP in both breeder hens and progeny.

Diet energy density is a major factor in broiler production costs, but metabolizable energy system has limitations in accurately predicting broiler performance due to its low sensitivity to actual metabolism. The productive energy (i.e., Arkansas Net Energy) system, which measures productive energy, provides a more accurate assessment of energy utilization, particularly under conditions affected by gut health, like enteritis and coccidiosis. This article highlights opportunities for assessing the effects of enteritis and coccidiosis on poultry energetics, evaluating dietary interventions on gut health, improving precision nutrition, and supporting One Health strategies in antibiotic-free production systems.

Abstract Methionine and cysteine are the principal sulfur-containing amino acids that are incorporated into proteins, although homocysteine and taurine also have important physiological roles in canines. As limited studies have been conducted for total sulfur-containing amino acids (TSAA) requirements across the canine life cycle, our objective was to determine the minimum requirements (MR) for TSAA at 4 life stages using the indicator amino acid oxidation (IAAO) technique. Labrador Retrievers (n = 24) were used in feeding studies to evaluate the changing requirements of TSAA as dogs mature: 6 puppies aged 10 to 14 wk, 6 puppies >14 wk to 9 mos, 6 adults 2 to 5 yr (yr), and 6 seniors > 8yr. Following a 2-d adaptation to a TSAA-adequate basal diet (TSAA = 1.12% dry matter), dogs underwent individual IAAO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of TSAA ranging from deficient to sufficient (final TSAA content in experimental diets were 0.41, 0.46, 0.51, 0.98, 1.05, and 1.12% dry matter, with indispensable amino acids formulated at 1.6x NRC values). The test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was included (a bolus L-[1-13C] phenylalanine based on body weight was first given, followed by [1-13C] Phe doses every 30 spanning 4 h). Breath samples were collected via a respiration mask every 30 min. Total CO2 production was determined via indirect calorimetry and production of 13CO2 at each dose was measured by enrichment of 13C in breath samples via isotope ratio mass spectrometry (IRMS). Results for IRMS data were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for TSAA were estimated to be 1.55 ± 0.069 g/1,000 kcal (mean ± 2 SD) for puppies 10 to 14 wk, 1.53 ± 0.21 g/1,000 kcal (mean ± 2 SD) for puppies 14 wk to 9 mo, 1.4 ± 0.30 g/1000 kcal (mean ± 2 SD) for adults 2 to 5 yr, and 1.27 ± 0.23 g/1,000 kcal (mean ± 2 SD) for seniors. These results may contribute to the formulation of diets that meet the age-appropriate requirements of TSAA for large-breed dogs at all life stages.

Methionine is a limiting amino acid in canine diets, but few requirement studies have been conducted across life stages in large-breed dogs. The objective of this study was to determine the minimum requirement (MR) for methionine (Met) in Labrador retrievers at 4 life stages using the indicator amino acid (AA) oxidation (IAAO) technique. In total, 24 dogs were used: 6 puppies aged 10 to 14 wk, 6 puppies aged 14 wk to 9 mo, 6 adults aged 2 to 5 yr, and 6 seniors aged over 8 yr in feeding studies to evaluate the changing requirements of methionine (Met) as canines age. After 2-d adaptation to Met-adequate basal diet (Met = 0.56% dry matter), dogs underwent individual IAAO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of Met ranging from deficient to sufficient (final Met content in experimental diets was 0.1982, 0.2386, 0.279, 0.49, 0.525, 0.56% dry matter, with indispensable amino acids formulated at 1.6x NRC values. Test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was supplied (a bolus L-[1-13C]phenylalanine based on body weight was first given, followed by [1-13C]Phe doses every 30 min spanning a 4-h period), and breath samples were collected via respiration mask every 30 min. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total CO2 production measured via indirect calorimetry and isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for Met were estimated to be 0.84 ± 0.05 g/1000 kcal (mean ± 2SD) for puppies 10 to 14 wk, 0.78 ± 0.16 g/1,000kcal (mean ± 2SD) for puppies 14 wk to -9 mo, 0.68 ± 0.19 g/1,000kcal (mean ± 2SD) for adults 2 to 5 yr, and 0.62 ± 0.17 g/1,000kcal (mean ± 2SD) for seniors. This research provides important information to assist in accurate formulation of diets that contain appropriate methionine for large breed dogs at all life stages.

Postbiotics are emerging as potential functional ingredients for companion animal diets. This study aimed to determine if a Saccharomyces cerevisiae-based postbiotic can alter cytokine and stress responses to exercise and transport stress in adult Labrador Retrievers. Dogs received 15 g ground corn germ (Control, n = 12), 7.5 g postbiotic (Low, n = 12), or 15 g postbiotic (High, n = 12), daily for 63 days. Exercise was twice weekly for 7 weeks, and a single transport per dog occurred in week 8. Fecal inflammatory biomarkers, serum chemistries, and complete blood counts were assessed at the beginning and end of the study. Serum cytokines were quantified before and 18–20 h after the first and last exercise runs. Gait analysis was assessed before and 24 h after the first and final runs. Saliva cortisol was measured before and after transportation. Treatment did not affect blood chemistries, gait, fecal biomarkers, or saliva cortisol (p ≥ 0.19). Eosinophils increased slightly in Controls (p = 0.01), though remained below 0.80 × 109 cells/L. Most cytokines were unaffected by treatment (p ≥ 0.15), but there were minor changes in circulating monocyte chemoattractant protein-1 (p = 0.01) and IL-8 over time at the initial run (p = 0.03) and IL-10 in males (p = 0.02) in the Low dose dogs. The High dose decreased Blautia (p = 0.04) slightly and tended to decrease Fusobacterium abundances (p = 0.07). The Low dose tended to increase Clostridium hiranonis (p = 0.07) slightly. The tested S. cerevisiae postbiotic produced small changes in immune function and gut microbial species in dogs.