Effect of replacing fish meal with enzymatic feather meal on growth and feed utilization of tilapia (Oreochromis niloticus ? O. aureus)

In trial 1, the enzymolysis time (30, 60 and 90 min), temperature (25 ?C, 45 and 60 ?C), moisture inclusion (500, 1000 and 1500 g/kg feather meal) and protease inclusion (0, 5, 10 and 15 g/kg feather meal) were designed to investigate the optimal enzymolysis conditions for feather meal. The result showed that the proper enzymolysis time, temperature, moisture inclusion and protease inclusion were 60 min, 60 ?C, 1000 g/kg feather meal and 10 g/kg feather meal, respectively. In trial 2, a total of 300 tilapia (14.00 ? 0.03 g) was fed one of five experimental diets as the control diet containing 6% fish meal (FM), two feather meal (FeM) substituted diets and two enzymatic feather meal (EFeM) substituted diets for 9 weeks, where FM was replaced at the ratios of 50 % (FeM-50, EFeM-50) and 100 % (FeM-100, EFeM-100). The results showed that there were no significant differences (P 0.05) in weight gain and feed conversion ratio among the control, FeM-50, EFeM-50 and EFeM-100 groups. The apparent coefficient digestibility of dry matter and protein were significantly decreased in the two FeM groups, and increased in EFeM-100 group (P < 0.05). In conclusion, enzymatic feather meal can replace fish meal in the diet of tilapia without negative effects on growth, nutrient retention and digestibility.

Automated summary

The optimal enzymolysis conditions for feather meal were found to be 60 min enzymolysis time, 60°C temperature, 1000 g/kg moisture inclusion, and 10 g/kg protease inclusion. Furthermore, enzymatic feather meal was demonstrated to be a suitable substitute for fish meal in tilapia diets, with no negative effects on growth, nutrient retention, and digestibility.