Determination of microbiocoenosis in the intestine of the Hisex Brown hens in ontogenesis using T-RFLP method

Microbiocoenosis in the gastrointestinal tract, especially in the ceca, play an important part in life processes of poultry. Identification of the structure and taxonomic composition of microorganisms in the cecum using molecular genetic methods serves as a crucial approach in understanding how a cecal microbiota interplays with the chicken organism during ontogenesis. For this purpose, we studied an intestinal bacterial community composition in the ceca of the Hisex Brown laying hens at age of 40, 155 and 315 days using T-RFLP and RTPCR. In the chickens studied, development of the cecal microbial communities, changes in their content, and appearance of new microorganisms occurred in the ontogeny. A broader spectrum of bacteria was found in 40- and 155-day-old birds (221 ± 11 and 258 ± 9 phylotypes, respectively) as compared with 315-day-old laying hens (178 ± 8 phylotypes). Also, 315-day-old birds showed the least content of unidentified phylotypes. In the ceca of adult hens, there was a change in the dominant microbial taxonomic groups including a higher proportion of acidutilising bacteria of the class Negativicutes and cellulolytic bacteria of the class Clostridia, with a lower content of the classes Bifidobacteriales and Bacillales. Lactobacteria (order Lactobacillales) showed a greater content in 315-day-old laying hens (33.15 ± 1.05%) as compared with 40- and 155-day-old birds (5.13 ± 0.23% and 24.58 ± 0.86%, respectively). The variety and number of bacteria in the ceca conventionally attributed to various pathogens of poultry diseases, including the genera Enterobacter, Pantoea, Listeria, Acinetobacter and Mycoplasma, families Campylobacteraceae and Pasteurellaceae, and phylum Fusobacteria, increased with the age of birds. Thus, during molecular genetic studies, the species composition and dynamics of the microbiocoenosis in the cecum of the Hisex Brown laying hens was determined as related to their ontogeny.