Effect of a cocktail of enzymes and probiotics on the growth and the bacterial enumeration in gut and effluents of red tilapia (Oreochromis niloticus × O. mossambicus)

This study has been executed to investigate the effects of a cocktail of enzymes and probiotics (EP) on the growth performance, the intestinal morphology and the bacterial enumeration in the intestine and the effluent of red tilapia (Oreochromis niloticus × O. mossambicus). Four levels of EP were added to a basal diet at levels of 0.00, 0.037, 0.062 and 0.100 g kg−1 to produce four diets coded as EP0 (control), EP1, EP2 and EP3, respectively. The fish (0.35 g fish−1) were fed the diets for 56 days. For growth and feed utilization results, EP3 produced the best values followed by EP2. EP1 and EP0 gave the lowest values. Total bacterial count and Lactobacillus enumeration in both fish intestine and effluent increased steadily with increasing EP level. Staphylococcus count in the fish intestine and in the effluent decreased inversely as EP level increased in diets. The height and density of the intestinal villi progressively increased as dietary EP level increased. These findings suggest that EP enhanced the growth and feed utilization, modulated the bacterial composition in the intestine and in the effluent and improved the intestinal structure. The optimum level of EP was found at 0.1 g kg−1 diet.