Effect of in ovo injected prebiotics and synbiotics on the caecal fermentation and intestinal morphology of broiler chickens

Abstract

Manipulations of the intestinal microbiota composition may improve the health and performance of chickens. In ovo technology allows the administration of a bioactive substance to enter directly into the incubating egg. The objective of the present study was to investigate the effect of in ovo administered prebiotics or synbiotics on microbial activity products in the caeca and the development of the small intestine of broiler chickens. Ross 308 male chickens hatched from eggs injected in ovo with prebiotics or synbiotics were used in this study. Five experimental groups were formed: C (Control) – injected with 0.9% NaCl, the Pre-1 and Pre-2 groups – injected with prebiotics: inulin or Bi2tos, respectively, and the Syn-1 and Syn-2 groups – injected with synbiotics: inulin with Lactococcus lactis subsp. lactis IBB SL1 or Bi2tos with Lactococcus lactis subsp. cremoris IBB SC1, respectively. At the age of 7, 21 and 35 days, 10 chicks of each group were randomly selected, weighed and slaughtered, and the jejunal samples were collected for histological examinations, whereas caecal samples were collected to analyse the end products of microbial fermentation. Synbiotic treatment increased bodyweight, as observed in the Syn-1 group (P < 0.05). The propionate molar proportion was highest in the groups treated with synbiotics, especially in the Syn-1 group (P < 0.01). Furthermore, the molar proportion of acetate was also lowest in the Syn-1 group (P < 0.05). In ovo synbiotics treatment increased the villus length : crypt depth ratio in the jejunal mucosa, which might improve nutrient absorption and contribute to the increased weight of chickens. These effects suggest that the in ovo administration of synbiotics may be an effective method to increase bodyweight, improve the short-chain fatty acid caecal profile and increase the villus length : crypt depth ratio in the jejunal mucosa. These effects were more pronounced in the Syn-1 group than the Syn-2 group.