Abstract
Seasonal quantitative and qualitative analyses of the bacterial flora associated with the intestine of hybrid tilapia (Oreochromis niloticus x Oreochromis aureus) cultured in earthen ponds in Saudi Arabia were carried out. The isolates were being identified to genus or species level. Total viable counts (TVC) of bacteria in the intestine varied between 6.8 plus or minus 1.9 x 10 to the sixth power to 7.5 plus or minus 1.4 x 10 to the seventh power colony forming units (cfu) g-1 in early summer, 1.6 plus or minus 2.0 x 10 to the sixth power to 5.1 plus or minus 2.5 x 10 to the seventh power cfu g-1 in summer, 3.1 plus or minus 1.4 x 10 to the eighth power to 1.3 plus or minus 2.2 x 10 to the ninth power cfu g-1 in autumn, and 8.9 plus or minus 1.8 x 10 to the fifth power to 1.3 plus or minus 0.9 x 10 to the seventh power cfu g-1 in winter. Altogether, 17 bacterial genera were identified from the intestine of tilapia. The bacteria were predominantly Gram-negative rods (77%). Aeromonas hydrophila, Shewanella putrefaciens, Corynebacterium urealyticum, Escherichia coli and Vibrio cholerae were the most abundant species with a prevalence of >10% in most cases except V. cholerae. Considerable numbers of Pseudomonas spp. were found only in winter. Photobacterium damselae, Pasteurella spp., Cellulomonus sp. and Bacillus sp. were present in some seasons of the year. [PUBLICATION ABSTRACT]