Effect of Partial or Complete Substitution of Fish Meal by Meat Meal in the Feed of Red Sea Bream ( <i>Pagrus major</i> ) on the Growth Performance and Feed Utilization

As fish meal (FM) has become an expensive protein source to sustainably use in aquafeeds due to its stagnant production and increased price, finding a FM replacer is essential for the advancement of sustainable aquaculture. This study examined the effect of partial or complete FM substitution by meat meal (MM) in feeds on the growth and feed utilization of red sea bream (<i>P. major</i>). Six diets with isoproteic and isolipidic were prepared. In the control (Con) diet, 55% FM was included. The partial (20%, 40%, 60%, and 80%) or complete (100%) of FM levels in the Con diet were substituted by MM, named the MM20, MM40, MM60, MM80, and MM100 diets, respectively. Four hundred and fifty juvenile (7.85 ± 1.851 g; mean ± SE) red sea bream were distributed into 18 tanks (25 juvenile/tank) with triplicate. Throughout an 8-week feeding period, all fish were carefully hand-fed twice daily. At the completion of the 8-week experimental period, weight gain, specific growth rate, and feed consumption of fish fed the Con, MM20, and MM40 diets were superior to fish fed the MM60, MM80, and MM100 diets. Feed efficiency of fish fed the MM20 diet was superior to fish fed the MM100 diet, but comparable to fish fed the Con, MM40, MM60, and MM80 diets. Protein efficiency ratio of fish fed the Con, MM20, MM40, and MM60 diets was higher than that of fish fed the MM100 diet. Protein retention of fish fed the Con, MM20, and MM40 diets was superior to fish fed the MM100 diet. The condition factor of fish fed the Con diet was higher than that of fish fed the MM80 and MM100 diets. Plasma and serum parameters and biochemical composition of fish, except for fatty acid profiles were not significantly influenced by dietary MM supplementation as a substitution for FM. In conclusion, FM up to 40% could be substitutable by MM in a 55% FM-based feed without significantly impairing the growth performance and feed consumption of red sea bream.