Microalgae as main ingredient for fish feed: Non-fish meal and non-fish oil diet development for red sea bream, Pagrus major, by blending of microalgae Nannochloropsis, Chlorella and Schizochytrium

A feeding experiment was conducted to survey proper microalgae species for non-fish meal and non-fish oil diet of red sea bream. Five iso-nitrogenous and iso-lipidic diets were formulated (CP 47%, CL 19%). Fish oil formulated non-fish meal diet was arranged as a control diet with soybean meal, soy protein concentrate and corn gluten meal (FO). Fish oil of FO was replaced by Nannochloropsis meal and Schizochytrium meal for each of two diets (NAN, SCH). Both microalgae meals were mixed in a diet (NS), and Chlorella meal was formulated in NS diet to replace plant protein source (NSC). Duplicated groups of juvenile red sea bream (5.9 g) were fed the experimental diets for 75 days to near satiation. The growth was the highest in NS and NSC diet group. The other algae meal formulated diets fed groups showed the similar growth performance to FO. In fatty acid profiles, NAN group showed the lowest n-3 LC-PUFA with low DHA content in fatty acid composition of total lipid in fish carcass and hepatic PL, but the other algae meal diet group showed no significant difference with FO group. The results might suggest blending microalgae and using them with high amount is a key strategy for development of non-fish meal and non-fish oil diet for red sea bream.

Automated summary

The experimental results indicate that blending microalgae and using them in high amounts is a key strategy for developing non-fish meal and non-fish oil diets for red sea bream.