In ovo supplementation of probiotics and its effects on performance and immune-related gene expression in broiler chicks

Abstract

Probiotics are live, nonpathogenic microorganisms known to have a positive effect on the host by improving the natural balance of gut microbiota. The objective of this study was to determine the effects of administering probiotics (Primalac W/S) in ovo on hatchability, early post-hatch performance, and intestinal immune-related gene expression of broiler chicks. At embryonic day eighteen, 360 Cobb 500 eggs were injected with sterile water (sham), 1 × 105, 1 × 106, or 1 × 107 (P1, P2, and P3 respectively) probiotic bacteria. Another 90 eggs remained non-injected to serve as a negative control. Measurements and tissue samples were taken on day of hatch (DOH) and days 4, 6, 8, 15, and 22. No significant differences were seen among groups for hatchability, feed intake, feed conversion ratios, or mortality. Body weight of P2 was significantly greater than that of the negative control, sham and P1 on d 4, and that of the negative control and P1 on d 6. A similar pattern was observed for BW gain (BWG) from DOH to d 4. Real-time PCR was used to investigate the expression of immune-related genes in the ileum and cecal tonsils. Other than an initial upregulation of inducible nitric oxide synthase on DOH, in ovo probiotic supplementation was associated with downregulated expression of Toll-like receptors-2 and -4, inducible nitric oxide synthase, trefoil factor-2, mucin-2, interferon-γ, and interleukins-4 and -13 in both the ileum and cecal tonsils, though expression patterns differed based on treatment, tissue, and time point evaluated. Taken together, these results indicate that in ovo supplementation of the probiotic product Primalac does not impact hatchability, can improve performance during the first week post-hatch, and is capable of modulating gene expression in the ileum and cecal tonsils.

In ovo and Dietary Supplementation of Probiotics Affects Post-Hatch Expression of Immune-Related Genes in Broiler Chicks

“…In this experiment, in ovo supplementation of probiotics had no effect on hatchability further corroborating our previous findings [22,26]. Very few studies have been published regarding the concept of administrating probiotics via the in ovo route.…”

“…A reduction in intestinal colonization by pathogenic bacteria may have eliminated the need for the induction of these genes. Several studies have demonstrated the ability of probiotics to modulate the levels of several cytokines; however, discrepancies have been noted due to differences in the bacterial strains, combinations of probiotic strains, and presence or absence of a challenge [15][16][17]22]. Further supporting our findings, many reports have noted decreases in immune-related factors.…”

“…The earliest attempts of connecting these concepts demonstrated promising results where Salmonella typhimurium colonization was reduced in chicks administered an undefined cecal culture of bacteria in ovo [24]. Unfortunately, negative results in terms of hatchability, performance, and mortality have been noted, though these consequences may be attributed to the probiotic strain used and delivery site [22,[24][25][26]. Edens et al demonstrated positive results administering Lactobacillus reuteri in ovo in hatching chicks and turkey poults [27].…”

“…In ovo technology represents a means to take advantage of this crucial time and promote early colonization of beneficial bacteria in order to stimulate intestinal and immune system development [4]. Few researchers have entertained the idea of administering probiotics in ovo, which recently has been gaining more interest [22,23]. The earliest attempts of connecting these concepts demonstrated promising results where Salmonella typhimurium colonization was reduced in chicks administered an undefined cecal culture of bacteria in ovo [24].…”

“…Similar results were also seen in turkey embryos. More recently, administration of a commercial (lactobacilli-and bifidobacteria-based) probiotic as early as day 18 embryonic age was shown not to impact hatchability and could enhance early performance [22] and reduce disease severity in broiler chickens challenged post-hatch [26]. The objective of this study was to determine the effects of administering a Lactobacillus-based probiotic (PrimaLac) in ovo and in the diet on broiler chick hatchability, post-hatch immune organ weights, and developmental expression of intestinal immune-related genes.…”