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An experiment was carried out to evaluate the short-term effect of supplementing a nucleotide-rich yeast extract (NRYE) on growth performance, gut structure, immunity and microflora of piglets raised under sanitary and unsanitary conditions. A total of 84, 21-day old piglets were used in this study; 42 piglets were raised in a room designated as the clean room that was washed once per week, whereas the other 42 piglets were raised in a room designated as the unclean room in which 7 kg of manure from the sow herd was spread on each pen floor on day 1 and 7 and the room was not washed throughout the experiment. The pigs were fed a corn-soybean meal-based diet without or with 0.1% NRYE. Each treatment had 7 replicate pens in each room, and each pen housed 3 pigs. Feed disappearance and BW were recorded on day 1 and 14. On day 14, one pig per pen was euthanized to collect ileum, mesenteric lymph nodes and spleen tissues, and cecum and colon digesta. Overall, NRYE supplementation did not affect growth performance in both clean and unclean conditions, improved kidney weight in both clean (P=0.0002) and unclean room (P<0.0001) and tended to improve the villus height/crypt depth ratio in the clean room (P=0.073). Supplementing NRYE was associated with upregulation of Ileal programmed cell death gene-1 (P=0.0003), interleukin (IL)-1β (P<0.0001), IL-6 (P=0.0003), IL-10 (P<0.0001) and tumor necrosis factor-α (TNF-α) (P<0.0001) in pigs raised in the unclean room. Supplementing the NRYE in pigs raised in the clean room suppressed growth of cecal Enterobacteriacea (P<0.0001) members and colonic Enterococcus spp. (P<0.019), improved proliferation of cecal Lactobacillus spp. (P<0.002) and colonic Clostridium cluster IV (P<0.011) and XVIa members (P<0.0002). Supplementing the NRYE in the unclean room improved proliferation of cecal Clostridium cluster IV (P<0.026) and suppressed proliferation of colonic Enterococcus spp. (P<0.037). In conclusion, supplementing the NRYE to piglets under unsanitary conditions improved ileal immune response by upregulating inflammatory cytokines, and positively modulated proliferation of beneficial gut bacteria and suppression of harmful ones in both clean and unclean rooms.

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Yeast bioactives (YB) may stimulate broiler breeders (BB) to increase deposition of immunoglobulins (Ig) in eggs. We investigated the effects of feeding YB (mixture of derivatives from whole yeast subjected to enzymatic hydrolysis) to BB and/or their offspring on growth performance, gut development, and immune function in broiler chickens challenged with Eimeria. The BB (Ross 708 ♀ and Ross ♂) were assigned to 2 groups (60 ♀ and 10 ♂) and fed basal or basal diet supplemented with 500 g of YB/Mt. A total of 250 fertile eggs per treatment were collected, incubated, hatched, and sexed. Additional egg samples were analyzed for IgA and IgY contents. A total of 160 broiler chicks (80 ♀ and 80 ♂) from each breeder experimental group were placed in cages based on sex and BW resulting in 32 cages for each BB treatment group. Cages (16 per BB treatment group) were allocated to basal broiler chick diet or basal diet supplemented with 500 g of YB/Mt. On day 9, half of each BB by broiler chick dietary treatments was challenged with 1 mL of Eimeria culture (100,000 oocysts of Eimeria acervulina and 25,000 oocysts of Eimeria maxima). On day 14, all birds were necropsied for intestinal lesion scores and samples. Feeding YB to BB increased (P < 0.05) IgA concentration in egg yolk. Eimeria challenge decreased (P < 0.05) pancreas weight, jejunal villus height (VH), and growth performance but increased spleen weight, intestinal mass and jejunal mucosa IgA concentration. Independent of Eimeria challenge, feeding YB to BB and/or to chicks resulted in higher (P < 0.001) jejunal VH compared with feeding it to BB only or not at all. In conclusion, Eimeria challenge reduced growth performance and had negative effects on indices of intestinal function and health. Feeding YB to BB increased deposition of IgA in hatching eggs and improved jejunal VH independent of Eimeria challenge when fed to BB and/or to broiler chicks.

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An experiment was carried out to investigate the effect of yeast-derived products and distillers' dried grains with solubles (DDGS) on growth performance, small intestinal morphology, and innate immune response in broiler chickens from 1 to 21 d of age. Nine replicates of 5 birds each were assigned to dietary treatments consisting of a control diet without antibiotic (C), and diets containing 11 mg/kg of virginiamycin, 0.25% of yeast cell wall (YCW), 0.2% of a commercial product Maxi-Gen Plus, 0.025% of nucleotides, 0.05% of nucleotides, or a diet containing 10% of DDGS. On d 21, 5 birds per treatment were euthanized and approximately 5-cm long duodenum, jejunum, and ileum segments were collected for intestinal morphology measurements. Cecal tonsils and spleen were collected to measure the gene expression of toll-like receptors TLR2b, TLR4, and TLR21, macrophage mannose receptor (MMR), and cytokines IFN-γ, IL-12, IL-10, and IL-4. No significant difference was observed for growth performance parameters. However, diets containing 0.05% of nucleotides and YCW significantly increased (P < 0.05) villus height in the jejunum. Furthermore, the number of the goblet cells per unit area in the ileum was increased (P < 0.05) in diets supplemented with yeast-derived products. The expression of TLR2b in the spleen was down-regulated for diets supplemented with nucleotides and antibiotic. In addition, lower expression of TLR21 and MMR was observed in the spleen of birds receiving yeast-derived products and antibiotic. However, expression of TLR4 in the spleen was up-regulated in diets supplemented with YCW and nucleotides. The expression of IFN-γ and IL-12 was down-regulated in the spleen of birds fed diets supplemented with yeast-derived products. In addition, inclusion of YCW, Maxi-Gen Plus, or 0.05% of nucleotides down-regulated the expression of IL-10 and IL-4 in the cecal tonsils. In conclusion, down-regulation of receptors and cytokines in spleen and cecal tonsils of birds fed diets supplemented with yeast-derived products may suggest that yeast products do not exert immune stimulating effect under normal health conditions.

An experiment was conducted to investigate the effects of phytase and 2 levels of fructooligosaccharide (FOS) supplementation on growth performance, bone mineralization, and P utilization of broiler chickens. A total of 210 day-old male broiler chickens (Ross) were randomly placed into 7 dietary treatments consisting of 6 replicates with 5 birds per pen. The experiment was designed as an augmented 2 × 3 factorial arrangement with 0 or 500 U/kg of phytase and 0, 0.5% or 1% of FOS added to a reduced Ca (0.8%) and available P (0.25%) negative control diet (NC). A positive control diet (PC) that contained 1% Ca and 0.45% available P was also included. During the entire experimental period, phytase supplementation significantly improved (P < 0.05) the feed conversion ratio (FCR), BW gain (BWG), and feed intake. Birds fed the PC diet showed significantly higher bone mineral density (BMD) and bone mineral content (BMC) in both femur and tibia bones (P < 0.0001) than those fed the NC diet. Phytase supplementation increased femur BMD (P < 0.05), whereas FOS decreased femur BMD and BMC (P < 0.05). Phosphorus utilization was significantly higher for the NC diet (P < 0.0001). Phytase alone and in combination with 0.5% FOS increased P utilization significantly when compared with other treatments (P < 0.05). Fructooligosaccharides, especially at the level of 0.5%, increased P retention. In conclusion, phytase supplementation in low Ca and P diets improved growth performance, bone quality, and P utilization. However, supplementing NC diets with phytase and FOS did not result in bone mineralization values comparable with that of the PC diet. The application of dietary FOS alone had a negative effect on broiler bone quality.