Effects of Zeolite Dietary Supplementation in Nile Tilapia (Oreochromis niloticus Linnaeus 1758) on Zootechnical and Histopathological Parameters

In order to investigate the effects of zeolite incorporation in the diet of Nile tilapia on growth performance, body composition, survival rate, and histopathology, five experimental diets were formulated. Diet 1 contained groundnut cake without zeolite (0% Zeo), Diet 2 contained 0.5% zeolite (0.5% Zeo), Diet 3 contained 1% zeolite (1% Zeo), Diet 4 contained 1.5% zeolite (1.5% Zeo), and Diet 5 contained 2% zeolite (2% Zeo). The experiment was conducted in an open system at Cheikh Anta Diop University and lasted for two months. Prior to the feeding trial, fish were subjected to an acclimation period. Each diet was randomly assigned to three tanks, with a stocking density of 20 fish per tank, for a total of 300 fry with an initial mean weight of 0.3 g. Fish were reared in 50-L plastic tanks and fed three times daily (09:00, 13:00, and 17:00) at feeding rates of 15%, 12%, and 10% of body weight during the first, second, third, and fourth two-week periods, respectively. Water temperature and dissolved oxygen were monitored twice daily (morning and evening). The results indicated that growth parameters (final mean weight, absolute mean weight gain, and relative mean weight gain) of fish fed diets containing 1%, 1.5%, and 2% zeolite did not show any significant differences. Fish fed the diet containing 0.5% zeolite exhibited the lowest growth performance. Feed conversion ratio (FCR) did not differ significantly among fish fed diets containing 0%, 1%, and 1.5% zeolite. Fish fed the diet containing 2% zeolite showed the best FCR, whereas those fed the 0.5% zeolite diet exhibited the poorest FCR. Survival rates ranged from 70% to 88.33%. Fish fed the diet containing 2% zeolite showed the lowest survival rate, while those fed diets containing 0.5% and 1.5% zeolite recorded the highest survival rate (88.33%). Villus degeneration in the small intestine was observed in fish fed diets containing 0%, 0.5%, and 1% zeolite. The posterior intestine of fish fed the 2% zeolite diet displayed a normal histological structure.