Enumeration and identification of bacteria in chicken semen

Three experiments were conducted to determine the bacteriological quality of chicken semen. Semen was collected from donor males, diluted, and surface inoculated onto seven different bacteriological media, from which randomly selected colonies were identified. Bacterial counts in semen averaged 5.14 log10 cfu/mL. Tryptic soy agar (TSA) was the best medium for the isolation of Gram-positive bacteria, whereas TSA + .3% bile salts (TSABS) and violet red bile agar + 1% glucose (VRBAG) were the best media for the isolation of Gram-negative and enteric bacteria. The genera of bacteria that were isolated depended on the medium that was used for isolation. The most frequently isolated genera included Escherichia, Staphylococcus, Micrococcus, Enterococcus, and Salmonella. Most of the bacteria that were isolated were endemic to poultry and were common environmental bacteria. This indicates that the environment and feed are important sources of bacterial contamination in broilers.