The effect of replacing fish meal with plant protein sources on growth performance and digestive enzymes activity in Asian sea bass (Lates calcalifer)

The aim of this study was to investigate the effect of replacing fish meal with plant protein sources on growth performance, digestive enzymes activity and also introducing a diet suitable for cultured Asian sea bass species in terms of biological efficiency. A total of 600 juveniles with an average weight of 54±2.5 gr were distributed in 15 tanks (500 liters) with a density of 40 pieces in each tank and were fed with prepared diets for 60 days. The composition of plant proteins (soybean meal, wheat gluten and corn gluten) was used at two levels of 35 and 70% to replace fish meal and the growth performance and activity of digestive enzymes were examined.The results showed that T1 (fish meal) and T2 (35% replacement) had the best performance in specific growth factor, weight gain percentage, relative growth rate, weight gain. Also, replacement of 70% fish meal with plant protein sources led to a significant reduction in specific growth rate, daily weight gain and relative growth rate compared to T1 (P<0.05).The results of gastrointestinal enzymes activity showed that the T4 (commercial 1) in alkaline phosphatase, lipase, α-amylase and the T2 in trypsin activity had a significant difference compared to other treatments (P<0.05). It can be inferred that Asian sea bass can easily have good growth performance by replacing 35% fish meal with plant protein sources.