Increasing fish meal replacement level with feather meal in golden pompano Trachinotus ovatus diet through gamma-ray irradiation

This study evaluated the potential to replace dietary fish meal with gamma-ray (gamma)-irradiated feather meal and non gamma-irradiated feather meal for golden pompano Trachinotus ovatus. The basal diet (R) contained 250 g/kg fish meal, and 20% and 40% of the fish meal were replaced by either gamma-irradiated feather meal (IF20 and IF40) or non gamma-irradiated feather meal (F20 and F40). Fish were fed the test diets in inshore net pens for eight weeks. The weight gain of fish fed diet R did not significantly differ from those fed diet IF20, but was higher than those fed diets F20, F40 and IF40. No significant differences were found in feed intake, feed conversion ratio, retention efficiencies of carbon and nitrogen, condition factor, hepatosomatic index and wastes of carbon and nitrogen between fish fed diet R and diets F20, F40, IF20 and IF40. This study reveals that gamma-irradiated feather meal could replace more fish meal in golden pompano diet than that replaced by non gamma-irradiated feather meal, and dietary fish meal content could be reduced to 200 g/kg by inclusion of 43 g/kg gamma-irradiated feather meal as a fish meal substitute. Replacing dietary fish meal with either gamma-irradiated feather meal or non gamma-irradiated feather meal could shift carbon-nitrogen-phosphorus atomic stoichiometry in the coastal waters for golden pompano aquaculture.