Bifidobacteria are obligate inhabitants of the crop of adult laying hens.

Modified TPY agar (MTPY; with addition of glacial acetic acid and mupirocin) was used in the enumeration of bifidobacteria from hen crop and faeces. The colonies on MTPY medium inoculated with crop and faeces samples were Gram-stained, screened for presence of fructose-6-phosphate phosphoketolase activity and tested for fermentation patterns using ANAEROtest kits. It was revealed that bifidobacteria are obligate inhabitants of the hen crop, reaching counts of 10(7)/g of crop content. The occurrence of bifidobacteria in the hen crop was evidently not the consequence of ingestion of faeces as all the bifidobacteria strains isolated from the hen crop fermented glucose and fructose, while most strains isolated from hen faeces did not ferment either glucose or fructose. The results suggest that bifidobacteria are common and may even be one of the predominant parts of the hen crop flora.