Poultry diets without antibiotics. II. INTESTINAL MICROBIOTA and PERFORMANCE of BROILER (Gallus gallus L.) breeders fed diets with a phytobiotic

Abstract

The worldwide experience is explicitly evidencing that genetically conditioned productivity potential in poultry can be realized only in healthy birds. Since the implementation of the antibiotic bans in EC countries a constant search for the effective alternatives to in-feed antibiotic growth promoters (AGP) is still in progress. The additives of different types (probiotics, prebiotics, synbiot-ics, symbiotics, acidifiers, phytobiotics) with growth-stimulating efficiency close to that in antibiotics and inducing no harmful effects become increasingly popular in practical poultry nutrition. The efficiency of phytobiotic Intebio based on the essential oils in diets for growing chicken of preparental lines B5 and B9 (selected by Smena Center for Genetic Selection) was studied. The parameters of growth efficiency, duodenal and circulatory activity of the digestive enzymes in fistulated birds, the results of molecular genetic analysis of the composition of duodenal and cecal microbiota are presented. It was found that live bodyweight in males and females in both lines at 21 weeks of age was similar in control treatments fed diets supplemented with AGP and experimental treatments fed diets supplemented with Intebio (3172 g in males and 2318 in females vs. 3169 and 2316 g, respectively, in control in B5 line; 2590 and 1917 g vs. 2589 and 1920 g in males and females, respectively, in B9 line). Reproductive organs (testicles in males and ovaries and oviducts in females) were normally developed in all lines and treatments. Supplementation of diets with the phytobiotic significantly increased lipase activity in the duodenal digesta in B5 line (by 30.9 %, р 0.05) and B9 line (by 98.3 %, р 0.01), and protease activity in B5 line (by 36.4 %, р 0.05). The activity of lipase in B9 line was significantly (р 0.001) lower in compare to B5 line in the duodenal digesta (by 59.9 %) and in blood serum (by 48.3 %). Digestibility of dietary dry matter in males and females of B5 line was higher by 3.11 % in compare to B9 line, digestibility of fat higher by 2.95 %, nitrogen retention higher by 2.12 %. The taxonomic composition of duodenal microbiota in both lines is found to be affected by the dietary phytobiotic. In phytobiotic-treated birds the significant increases were found in the duodenal populations of certain polysaccharide-fermenting species (phylum Bacteroides, class Clostridiales) and species with high antagonistic activity against avian pathogens (Bifidobacterium spp., Bacillus spp.).