No abstract

The feasibility of establishing probiotic bacteria in the intestine of broiler chickens by in ovo inoculation was investigated, followed by verifying possible subsequent protection against Salmonella Enteriditis infection. In a first study, 7 commercially available probiotics were screened for compatibility with in ovo inoculation. Two of these probiotics, one being a Enterococcus faecium and the other a Bacillus subtilis, were selected for colonizing the chick gut without compromising hatchability. In a second study, these 2 products were administered in ovo and in the feed to chicks reared until 18 d in comparison with noninoculated chicks and with chicks fed an antibiotic. All chicks were orally challenged with Salmonella Enteritidis at 4 d of age. Results showed reduced performance of Salmonella Enteritidis challenged chicks fed no additives compared with challenged chicks fed antibiotic, but no significant differences in mortality was observed. Probiotics offered in ovo or through the diet could only partially recover performance compared with antibiotic-fed chicks. A significant reduction in the number of Salmonella Enteritidis positive chicks was observed when chicks were in ovo inoculated with E. faecium and continued receiving it in the diet. This work establishes standards for future in ovo colonization research and emphasizes its value as a promising method to deliver individual precise dose of probiotics to poultry in mass scale at the earliest possible age based on the competitive exclusion concept. In ovo colonization with probiotic can therefore become an important ally in combination with other approaches to combat Salmonella and other intestinal bacterial infections in poultry.

Microbiota plays a role in the release and absorption of nutrients from feed components, thereby affecting digesta composition and moisture content of the excreta. The objective of the current study was to determine the effects of 5 different diets varying in ingredients (medium-chain fatty acids, nonstarch polysaccharides, and starch) on the microbiota composition of ileal digesta of broiler chickens and excreta DM content. Each treatment was repeated 6 times in cages each containing 18 Ross 308 broilers, with growth performance measured from 0 to 34 d of age and excreta DM and ileal microbiota composition analyzed at 34 d of age. Microbiota composition was evaluated using a novel ribosomal RNA microarray technology containing 370 different probes covering various genera, groups of microbial species, and individual species of the chicken gut microbiota, of which 321 had a signal above the background threshold. Replacing part of the animal fat and soybean oil in the wheat-based diet with medium-chain fatty acids (MCFA; 0.3% C10 and 2.7% C12) improved feed efficiency compared with the other dietary treatments. This coincided with a suppression of gram-positive bacteria belonging to the phylum of the Firmicutes, including Lactobacillus species, and species belonging to the family of the Enterococcaceae and Micrococcaceae, whereas the gram-negative bacteria belonging to the family of the Enterobacteriaceae were promoted. None of the other diets used in the present study notably changed the ileal digesta bacteria composition. Excreta DM content was not affected by dietary treatment. The variation between individual birds per dietary treatment was more pronounced than variation caused by feed composition, with the exception of the digesta microbiota of the birds fed the MCFA diet. It is concluded that a diet with MCFA significantly changes the ileal microbiota composition, whereas the effect of the other diets on the composition of the microbiota and excreta DM content is small in broiler chickens.

increase in IL-2Rα + NK cells and enhanced NK cell activation. The observed association between early life development of intestinal microbiota and immune system indicates possibilities to apply microbiota-targeted strategies that can accelerate maturation of intestinal microbiota and strengthen the immune system, thereby improving the health and resilience of broiler chickens.

Some of the challenges faced by neonatal turkeys include weakness, reduced feed intake, impaired growth, susceptibility to disease, and mortality. These symptoms may be due to depleted energy reserves after hatch and an immature digestive system unable to replenish energy reserves from consumed feed. To better understand enteric development in turkeys just before hatch, a new method was used to identify the patterns of intestinal gene expression by utilizing a focused microarray. The duodenums of 24 turkey embryos were sampled on embryonic day (E)20, E24, E26, and hatch (E28). The RNA populations of 96 chosen genes were measured at each time point, from which 81 significantly changed (P < 0.01). These genes were clustered by gene expression pattern similarity into 4 groups. The expression pattern of hormone receptors revealed that intestinal tissues may be less responsive to growth hormone, insulin, glucagon, and triiodothyronine during the last 48 h before hatch, when developmental emphasis switches from cell proliferation to functional maturation. Based on gene expression patterns, we concluded that at hatch, poults should have the capacity to 1) digest disaccharides but not oligopeptides, due to increased expression of sucrase-isomaltase but decreased expression of aminopeptidases and 2) absorb monosaccharides and small peptides due to high expression of sodium-glucose cotransporter-4 and peptide transporter-1.