| Experimentation on the effects of clinoptilolite inclusion in the diets of the Nile tilapia (Oreochromis niloticus) on production was conducted in four different parts.; In the first study growth of the fish was best with the diets of 36% (30.8% determined experimentally) DP and 229 kcal DE/100 g. Addition of 1% Z gave the best growth at all three protein levels. These differences in growth were not significant (P > 0.05), but they are consistent with other significant (P < 0.05) advantages in the favor of the 36% PD level in the variables: total protein ingested, total DP intake, g DP/100 g of diet, total DE intake, energy digestibility, kcal DE/100 g of diet, total protein gained by the fish and total energy gained by the fish.; In the second study that employed feeding one saturation meal in the morning, the 36% DP level again gave best results in most of the variables related to intakes, growth, digestion and body composition. But the relative advantage in growth over the other DP levels was less than in the first study with twice a day feeding. Significant differences in favor of 36% DP are found only for protein intake and DP concentration in the diet.; In the third phase of this work to evaluate the three clinoptilites and sand as additive ingredients at 2% of inclusion in diets of 31% DP, there were no significant differences (P > 0.05) among treatments, but the diets with natural zeolite and zeolite-Na+ resulted in the greatest growth in body weight; the latter was the diet least consumed but the one most efficient in feed conversion, while the diet with sand gave the poorest growth and feed efficiency. The zeolite-NH4+ diet resulted in the greatest consumption of feed, protein and energy, the greatest body gains of protein, lipid and energy, and the most efficient utilization of these components.; In the fourth phase, laboratory testing of pellets showed that those of the diet with natural zeolite were slightly more stable in the water than those of the diet with sand. Both diets gave rather similar results in individual body weight gain, total feed intake and total residual feed and its distribution in different parts of the RSCA, with the exception of a significantly greater amount of solids in the sponges for the diet with sand, which is attributed to defects of the filters, which were of a unsatisfactory design. The nitrogen of the solids in the sponges was higher for the sand diet while that of the solids suspended in the water was higher for the natural zeolite diet. (Abstract shortened by UMI.)... |
