Evaluating fungi-degraded date pits as a feed ingredient for Nile tilapia Oreochromis niloticus L.

Five isocaloric-isonitrogenous diets containing 0, 150, 300, 450 and 600 g kg^-1 of fungi Trichoderma reesei-degraded date pits (DDP), as a replacement for dietary corn, were fed to triplicate groups of Nile tilapia Oreochromis niloticus L. fingerlings (1.88 g initial weight), for 9 weeks, in 70 L fibreglass tanks. Each tank was considered as an experimental unit and was part of a water recirculating system utilizing filtered and aerated ground well water (24 ± 3°C). Tilapia growth performance, namely, weight gain, feed conversion, specific growth rate and protein efficiency ratio were similar and superior in fish fed diets containing 150 and 300 g kg^-1 DDP, when compared with those fish fed the other diets. Fish fed the control diet with 450 g kg^-1 DDP had better growth efficiency performance than those fed diets containing 0 and 600 g kg^-1. Fish fed the diet with 600 g kg^-1 DDP were inferior to all other groups. Tilapia body composition was affected by increasing DDP level in the diets as body fat was decreased, while body moisture was increased. In conclusion, DDP could replace 300 g kg^-1 of dietary corn with better growth results. Further increase of date pits replacements to 450 g kg^-1 will affect growth performance, when compared with the control.