In ovo supplementation of Primalac and the effects on performance and immune response of broilers

Probiotics are live nonpathogenic microorganisms capable of positively impacting the host by improving the natural gut microbial balance and promoting animal health. In ovo technology represents one means to administer probiotics and promote early colonization of beneficial bacteria for stimulating intestinal and immune system development, and warding off enteric threats. Three studies were conducted to evaluate the effects of in ovo administration of Primalac in broilers. The objective of the first study was to determine the effects of administering probiotics in ovo on hatchability, post-hatch performance and expression of immune-related genes in the ileum and cecal tonsils. On embryonic day 18, 360 eggs were injected with water, 1x105, 1x106, or 1x107 probiotic bacteria. Another 90 eggs remained uninjected as a negative control group. Measurements and tissue samples were taken on day of hatch (DOH) and days (d) 4, 6, 8, 15, and 22. A subsequent study was conducted to evaluate the effects of administering Primalac in ovo and in the diet on broiler chick hatchability, post-hatch performance, immune organ weights and ileal immune-related gene expression. At embryonic day 18, 1977 eggs were either not injected (negative control), dry-punched, or injected with 1x106 or 1x107 probiotic bacteria. Performance parameters were measured on DOH and d4, 6, 8, 14, 19, and 42, while immune organ weights and tissue samples were taken on DOH and d4, 6, 8, 14, and 20. A third study investigated the effects of in ovo administration of Primalac on hatchability, performance, immune organ weights, and lesion scores in broiler chicks exposed to Eimeria sp. At embryonic day 18, 210 eggs were injected with either sterile water or 1x106 probiotic bacteria. On d3 post-hatch, half of the chicks from each treatment group were challenged with a mixed inoculum of Eimeria acervulina, E. maxima, and E. tenella. Measurements and tissue samples were taken on DOH and d3, 9 and 15. The results of these studies suggest that in ovo Primalac supplementation does not negatively impact hatchability, enhances performance, modulates intestinal gene expression, and provides protection against a mixed Eimeria infection.