J. B. Carey

Immunomodulatory Effects of Saccharomyces cerevisiae Fermentation Product Supplementation on Immune Gene Expression and Lymphocyte Distribution in Immune Organs in Broilers

A study was conducted to evaluate the molecular and cellular immunomodulatory effects of a Saccharomyces cerevisiae fermentation product (Original XPC, Diamond V) in broilers. Our lab has previously demonstrated that broilers fed XPC generate faster and stronger antigen-specific humoral immune responses to Newcastle disease virus (NDV) vaccination. This study aims at investigating the mechanism behind this increased immunocompetence. One-day-old broilers were randomly assigned to one of two treatments: 1.25 kg/ton S. cerevisiae fermentation product (XPC treatment group) or control diet. Birds were vaccinated against NDV on day 1 (B1 strain) and day 21 (LaSota strain) post-hatch. Innate and adaptive immune-related gene expression profiles in central (thymus and bursa of Fabricius) and peripheral (spleen) immune organs were investigated at 14 and 28 days of age by qPCR array. Fold changes larger than 1.2 (P < 0.05) between treated and control were considered significant. Lymphocyte subpopulations in central and peripheral immune organs and blood leukocytes were analyzed by flow cytometry at 14, 21, 28, and 42 days of age. In the spleen, Th1 immune responses and antiviral genes, such as IFN-γ, and its downstream genes signal transducer and activator of transcription (STAT4) and NFκB, were significantly upregulated in the treated group by 14 days of age. In the thymus, genes belonging to different functional groups were influenced at different time points. Cytokine genes associated with lymphocyte maturation, differentiation, and proliferation, such as IL-1R, IL-2, and IL-15 were significantly upregulated in the treated group by 28 days of age. Genes preferentially expressed in the medulla of the thymus and mature thymocytes, such as Myxovirus resistance gene 1, interferon regulatory factor-1, interferon regulatory factor-7, and STAT1, were upregulated in the birds supplemented with XPC. Birds supplemented with XPC had significantly higher percentages of CD3+, CD4+, and CD8+ T-cells in the thymus at day 28 of age, indicating production of more mature T-cells, which was consistent with gene expression results. Results suggest that XPC supplementation primes broilers to become more immunocompetent, without compromising growth performance.

Effects of a Commercial Mannan-Oligosaccharide Product on Growth Performance, Intestinal Histomorphology, and Amino Acid Digestibility in White Pekin Ducks

SUMMARY Two identical experiments were conducted to evaluate the effects of a commercial mannan‐oligosaccharides product. Both experiments included treatment of 0, 250, 500, 1000, and 2000 g/ton of a prebiotic yeast cell wall product containing mannan‐oligosaccharides (YCW‐MOS). Addition of YCW‐MOS to duck diets decreased (P ≤ 0.0001) day 21 feed consumption about 90 g per bird, decreased (P ≤ 0.0198) day 1‐21 feed conversion ratio by as much as 6 points. Productivity index at day 21 increased (P ≤ 0.0179) by as much as 31 points. There were no effects of YCW‐MOS on intestinal length, weight, index, and digesta viscosity. However, the YCW‐MOS‐treated groups had as much as 26% greater (P = 0.0439) area of jejunal goblet cells, 12% greater quantity of jejunal goblet cells (P = 0.0350) and as much as 43% greater (P = 0.0233) numbers of ileal goblet cells than the control group. The YCW‐MOS‐treated group also had greater cysteine (P = 0.0057), histamine (P = 0.038), and tryptophan (P = 0.0070) ileal digestibility (6‐8 points improvement) than the control group. This study demonstrated that addition of 1 kg/ton of mannan‐oligosaccharides in duck feeds affects duck live performance and produces modest changes in gut morphology and amino acid digestibility.

Effects of a Commercial Beta-Mannanase Product on Growth Performance, Intestinal Histomorphology, Bone and Body Composition, and Amino Acid Digestibility in White Pekin Ducks

SUMMARY Two experiments were conducted to evaluate effects of a commercial &bgr;‐mannanase in duck diets 1‐21 d. Both experiments included 0%, 0.01%, 0.05%, 0.1%, and 0.2% of &bgr;‐mannanase treatments. Experimental units of 5 birds per pen were replicated 8 times in 4 different rooms. The data were analyzed as a 2 (Experiment) × 5 (Treatment) × 8 (Replicate) factorial analysis. Body weight of all &bgr;‐mannanase groups was ˜66 g and ˜79 g greater than control fed birds at day 14 and 21, respectively. All &bgr;‐mannanase groups had an average of 0.1, 0.14, and 0.08 lower feed conversion than controls at day 7, 14, and 21, respectively. Productivity index increased over controls by an average of 41, 81, and 48 on day 7, 14, and 21, respectively. Illeal length of all &bgr;‐mannanase groups was greater than controls, and the 0.01% and 0.05% &bgr;‐mannanase groups had ˜0.66 lower ileal viscosity than controls. Ducks fed 0.10% &bgr;‐mannanase had greater ileal villi height than control, 0.01%, and 0.20% &bgr;‐mannanase groups. Feeding diets with 0.05%, 0.10%, and 0.20% &bgr;‐mannanase resulted in greater ileal villi width compared to controls. These treatments had greater ileal crypt depth than control and 0.05% &bgr;‐mannanase groups. All &bgr;‐mannanase treated groups had greater amino acid digestibility than controls. &bgr;‐Mannanase at 0.10% resulted in a lower percentage of fat and greater bone strength than control and 0.20% &bgr;‐mannanase. This study demonstrated that addition of &bgr;‐mannanase positively affects duck growth performance, gut morphology, and digestibility.

Effects of feeding original XPCTM to laying hens on egg production, component yield and composition

SUMMARY The U.S. market for eggs has evolved into a diverse and profitable system. In recent years, customers have increased their demand for eggs and egg products in liquid form; as a result, a segment of the egg industry has placed more emphasis on yolk and albumen yield, eggshell quality, and egg solids. In the current experiment, an examination of the effects of a Saccharomyces cerevisiae fermentation product (Original XPCTM) on egg component yield and composition from laying hens was performed. The experiment was conducted using 102 Hy‐Line W‐36 hens from 19‐53 weeks of age. Standard layer rations (CON) were compared with those supplemented with the fermentation metabolite product (FM) at 1.25 kg/metric ton. Hen‐day egg production and egg mass were not different between the treatments during 0‐35 wks of lay. Feed conversion (feed: egg) for hens fed the FM diet was significantly higher than the CON. Yolk weight, percentage of yolk yield, and percentage of yolk solids were significantly greater for the hens fed the FM diet: however, the percentage of yolk nitrogen was significantly greater for hens fed the control diet. The percentage of albumen nitrogen was significantly higher in eggs from hens fed the FM diet. These results suggest that FM had a significant influence on yolk yield and composition, and nitrogen content in albumen of eggs laid from laying hens fed FM diets at a level of 1.25 kg/MT.