Impacts of Dietary Protein and Prebiotic Inclusion on Liver and Spleen Gene Expression in Hy-Line Brown Caged Layers.

The ingredients of poultry feeds are chosen based on the least-cost formulation to meet nutritional requirements. However, this approach can lead to the introduction of anti-nutritional ingredients in the feed. The objective of this study was to evaluate the impacts of two diets (with or without prebiotic) on homeostatic genes in the liver and spleen of laying hens. Hy-Line Brown layers were raised either on a soybean meal or cottonseed meal-based diets with and without an added prebiotic (yeast cell wall), totaling four experimental diets. A total of 120, 63-week old layers were housed individually in a wire cage system. We investigated differences in the expression of select homeostatic marker genes in the liver and spleen of hens from each treatment. We then used the ΔΔCT and generalized linear models to assess significance. Results show that the inclusion of prebiotic yeast cell-wall (YCW) increased the expression of the BAK gene in the liver tissue for both the soybean meal (SBM) and cottonseed meal (CSM) diets. For splenic tissue, the combination of YCW with the CSM diet increased the POR gene over six log2 fold. Altogether, our results suggest altered homeostasis, which can have consequences for health and performance.

The Role of Housing Environment and Dietary Protein Source on the Gut Microbiota of Chicken.

The gut microbiota of chicken has received much attention due to its importance for bird health, food safety, and performance. In the United States, the impending transition to cage-free housing environments has raised many questions about its consequences for poultry health, productivity, and welfare. Therefore, we investigated how housing environments and feed composition affect the poultry gut microbiome. Such data is necessary to inform the design of production systems that promote health and food safety. In this study, we investigated the cecal microbiome of both caged and cage-free laying hens that were fed either an industry-standard soy-based versus a soy-free diet. Caged hens were housed in standard industry-style layer cages with one bird per cage, and cage-free hens were housed in a poultry barn with an outdoor enclosed yard with multiple hens per pen. Our study showed significant differences in the gut microbiota between cage-free and caged environments. Cage free housing generated higher diversity compared to caged housing. Furthermore, we observed a synergistic interaction of soy-based feed in cage-free housing, as the cage-free soy group showed the highest alpha diversity, whereas the caged-soy group showed the lowest diversity overall.

Performance of broilers fed diets supplemented with two yeast cell wall strains using two feeding strategies.

Different supplements or strategies have been proposed as alternatives to the use of antibiotics at sub-therapeutic levels in chickens. Mannan oligosaccharides and ß-glucans, yeast cell wall fractions (YCW), have been reported to beneficially influence broiler performance and health. Two differently produced yeast cell wall fractions derived from Saccharomyces cerevisiae were evaluated in this study using two different supplementation strategies offered to full-term broilers. The birds were placed in floor pens on used pine-shaving litter to increase potential microbial stress and mimic industry practice. The study utilized a three-phase feeding program with a 1- to 21-day starter, 21- to 35-day grower and 35- to 42-day finisher phases. Five dietary treatments were compared in this study. The experimental diets consisted of a control basal broiler diet; or the basal diet supplemented with the two differently produced fractions of YCW. The YCW products were supplemented at a constant 250 ppm or a decreasing concentration program (500, 250, 125 ppm) throughout the three feeding phases. Birds fed diets supplemented with either YCW products at any inclusion regimen demonstrated higher (P < 0.05) body weight (BW) in all three phases than control birds. The difference in final 42-day BW of the YCW treatments (3041 g) averaged 165 g higher (P < 0.05) than the control group. For all YCW treatments, productivity index was higher (P < 0.05) in the grower (418) and finisher phase (441) versus control birds (389 grower and 415 finisher). These results suggested that both YCW fractions prepared from Saccharomyces cerevisiae can improve broiler performance when added at either a constant rate (250 ppm) or at a decreasing rate from 500 ppm for the starter to 125 ppm for the finisher phase.

Assessing effects of yeast cell wall supplementation on threonine requirements in broilers as measured by performance and intestinal morphology.

The objective of this study was to evaluate whether or not the use of a prebiotic yeast cell wall (YCW) affects threonine requirements in starter broilers. Two hundred and forty 1-d-old Ross 308 broiler chickens were distributed among 2 Petersime battery brooder units (48 pens; 5 birds per pen). Different threonine to lysine ratios (0.60, 0.65, and 0.70 to 1.0) with 1.22% available lysine with and without YCW at 250 ppm was fed to the chickens in order to evaluate performance and intestinal morphology over a 21-d trial. A basal diet with 22% protein and 2,980 kcal/kg ME was prepared to create the 6 dietary treatments. The calculated lysine concentration was 1.34%, whereas threonine was 0.81, 0.88, and 0.94%, respectively. Pen weights and feed consumption were recorded at d 1, 7, 14, and 21 of the experiment. Jejunal and ileal samples were collected on d 21 for histology analysis to evaluate villi height (VH), crypt depth, villi width (VW), and muscularis thickness. A threonine to lysine ratio of 0.7:1.0 resulted in significant improvement of performance variables with increased jejunum VW and ileum VH compared with the other threonine to lysine ratios. Adding YCW to starter broiler did not affect the requirement for threonine.

Influence of different yeast cell wall preparations and their components on performance and immune and metabolic pathways in Clostridium perfringens-challenged broiler chicks.

A study was conducted to evaluate the influence of the purification of yeast cell wall (YCW) preparations on broiler performance and immunogenic and metabolic pathways under microbial challenge. A total of 240 (day old) chicks were distributed among two battery brooder units (48 pens; 5 birds/pen; 8 replicates/treatment). A basal starter diet was divided into 5 batches to create 6 dietary treatments; non-challenge (NCh-C) and challenge (Ch-C) controls, semi-purified YCW containing cytosol contents (SPYCW; 250 mg/kg), purified YCW (PYCW; 250 mg/kg), 50% purified beta-glucan (BG; 130 mg/kg), and 99.9% purified mannan-oligosaccharide (MOS; 53 mg/kg). All birds were immunocompromised with infectious bursal disease vaccine (10× the recommended dose) on day 10 and then all birds except NCh-C birds were challenged with Clostridium perfringens (Cp) (107 cfu/mL) via oral gavage on days 16 and 17. On day 21, tissue samples were collected from the jejunum and duodenum for analysis with chicken-specific, peptide arrays to study the influence of YCW supplementation on immune and metabolic kinase pathways. On day 16, SPYCW had significantly lower body weight (BW) and weight gain (WG) than other treatments except BG (P < 0.05). The productivity index (PI) was lower in SPYCW and BG than in NCh-C, Ch-C, and PYCW. On day 21, after the Cp challenge, NCh-C was higher than Ch-C, SPYCW, and BG in BW, WG, and PI (P = 0.03). The PI of PYCW was similar to NCh-C. The addition of purified YCW to the starter broiler diets influenced the immune and metabolic pathways in the gut. A total of 459 and 367 peptides in the duodenum and jejunum, respectively, were changed due to the Cp challenge. The YCW treatments had different degrees of influence on these peptides for both the duodenum and jejunum. These results suggest that relative purification of YCW and specific fractions of the YCW can influence broiler performance differently during microbial challenges and can alleviate the impact of these stressors.

Comparison of eggshell surface sanitization technologies and impacts on consumer acceptability.

Shell eggs can be contaminated with many types of microorganisms, including bacterial pathogens, and thus present a risk for the transmission of foodborne disease to consumers. Currently, most United States egg processors utilize egg washing and sanitization systems to decontaminate surfaces of shell eggs prior to packaging. However, previous research has indicated that current shell egg sanitization technologies employed in the commercial egg industry may not completely eliminate bacteria from the surface of eggshells, and thus alternative egg sanitization technologies with the potential for increased microbial reductions on eggshells should be investigated. The objectives of this study were to compare the antimicrobial efficacy and consumer sensory attributes of industry-available eggshell sanitization methods (chlorine and quaternary ammonium compounds (QAC) applied via spray) to various alternative egg sanitization technologies. Eggs (White Leghorn hens; n=195) were obtained for evaluation of sanitizer-induced reduction in mesophilic aerobic bacteria (n=90) or inoculated Salmonella Enteritidis (SE) reduction (n=105). Sanitizing treatments evaluated in this experiment were: chlorine spray (100 ppm available chlorine), QAC spray (200 ppm), peracetic acid spray (PAA; 135 ppm) alone or in combination with ultraviolet light (UV; 254 nm), and hydrogen peroxide (H2O2; 3.5% solution) spray in combination with UV (H2O2+UV). For enumeration of aerobic bacteria, eggs were sampled at 0, 7, and 14 days of storage at 4°C; surviving SE cells from inoculated eggs were enumerated by differential plating. Sensory trials were conducted to determine consumer liking of scrambled eggs made from eggs sanitized with chlorine, QAC, H2O2+UV, or no treatment (control). The H2O2 and UV treatment resulted in the greatest reductions in eggshell aerobic plate counts compared to other treatments throughout egg storage (P<0.05). All treatments utilized reduced SE below the limit of detection by eggshell rinse. There were no differences in consumers' liking of overall flavor between the 4 treatments evaluated. The application of H2O2+UV treatment to shell eggs represents a novel technology that could have important implications for egg quality and safety preservation.