Effects of dietary phospholipid levels on growth performance, fatty acid composition and antioxidant responses of Dojo loach Misgurnus anguillicaudatus larvae

Abstract

A 30-day feeding trial was conducted to determine the effects of different levels of dietary phospholipids (PLs) on growth performance, fatty acid composition and antioxidant enzyme activities of loach Misgurnus anguillicaudatus larvae. After 15 days post-hatching, larvae were fed five isoproteic and isolipidic formulated diets with different levels of PLs: 0% (PLs0.8), 2% (PLs1.6), 4% (PLs1.9), 6% (PLs2.3) and 8% (PLs3.0). Results showed that dietary PLs supplementation significantly improved survival and growth of larvae. Survival rate (SR) and body weight gain (BWG) in larvae fed the PLs2.3 diet were significantly higher than those fed PLs0.8, PLs1.6 and PLs1.9 diets, and no differences on SR and BWG were observed between PLs2.3 and PLs3.0 groups, indicating that a supplement of more than 2.3 g 100 g− 1 of PLs in diet was required for loach larvae. Dietary PLs supplementation significantly increased fat content and the ratio of neutral lipid (NL)/polar lipid (PL) in the whole body. Concentrations of 20:5n-3 and total n-3 fatty acids in the whole body significantly increased in NL and significantly decreased in PL with incremental dietary PLs levels. Dietary PLs supplement significantly increased superoxide dismutase activity and reduced activities of catalase and glutathione peroxidase in the whole body. These results indicated that supplementation of more than 2.3 g 100 g− 1 of PLs in diet could improve growth and survival of loach larvae.