Glycerol inclusion in the diet of Nile tilapia (Oreochromis niloticus) juveniles

The present study evaluated the effects of inclusion of glycerol in the diet of Nile tilapia juveniles on growth performance, biochemical changes in blood, and carcass composition. We used 300 Nile tilapia juveniles with an average initial weight of 29.15 +/- 8.40g and 11.55 +/- 0.87cm in length, distributed in 20 fiberglass tanks with a capacity of 250L. The experiments followed a completely randomized design with five treatments and four replications during 79days. The animals were fed diets containing four concentrations of glycerol (25g kg1, 50g kg1, 75g kg1 and 100g kg1) and a control diet without glycerol. HDL was the only biochemical parameter, that showed statistically different (P<0.05) results; it was higher in the groups fed with 0 and 75g kg1 glycerol compared to the other groups. No significant difference was observed in the results from the carcass composition of tilapia juvenile fed with the different glycerol levels, except for lipids (P<0.05), which showed the highest values in fish fed with 50g kg1 glycerol and the lowest in fish fed with 100g kg1. Glycerol can be used in fish diets as an energy supplement without causing damage to growth performance or to the biochemical and carcass composition of Nile Tilapia juveniles.