Aurantiochytriumsp. meal as DHA source in Nile tilapia diet, part I: Growth performance and body composition

Abstract

This study evaluated the inclusion of Aurantiochytrium sp. (ALL-G-RICH™), a source of docosahexaenoic acid (22:6 n-3, DHA), in the diet of Nile tilapia and its effect on growth performance indexes and body composition. Fish (initial mean weight 8.35 ± 0.80 g) were fed different dietary inclusion levels of ALL-G-RICH™: 0.00, 0.05, 0.10, 0.20, and 0.40 g/kg and a control diet using cod liver oil (CLO), to provide DHA content comparable to the inclusion of 0.10 g/kg ALL-G-RICH™. Although there was no significant effect (p > 0.05) on weight gain, specific growth rate, feed conversion, protein retention rate, and proximal body composition, the inclusion of ALL-G-RICH™ in the Nile tilapia diet influenced positively the fatty acid profile in the body, resulting in a high DHA concentration. CLO-fed fish accumulated significantly more DHA compared to those fed 0.10 g/kg ALL-G-RICH™ (p < 0.05). A digestibility trial was also performed for ALL-G-RICH with 65.86 g mean-initial-weight fish. The digestibility was high for DHA (96.10%); however, it was low for palmitic acid (70.81%). The results show that the inclusion of up to 0.40 g/kg ALL-G-RICH™ can be used in Nile tilapia diets without impairing growth performance.