Regulation of growth, fatty acid profiles, hematological characteristics and hepatopancreatic histology by different dietary n-3 highly unsaturated fatty acids levels in the first stages of juvenile Pacific white shrimp (Litopenaeus vannamei)

Abstract

An 8-week feeding experiment was conducted to investigate the effects of dietary n-3 highly unsaturated fatty acids (n-3 HUFAs) on growth performance, fatty acid profiles, hematological characteristics and hepatopancreatic histology in juvenile Pacific white shrimp (Litopenaeus vannamei) (initial average weight, 0.14 ± 0.01 g). Six isoproteic and isolipidic diets were formulated with graded levels of n-3 HUFA (0.24, 0.53, 0.86, 1.25, 1.58 and 1.97 % of dry matter), and the 0.24 % group was used as control group. The results revealed that shrimp fed the diet containing 0.86 % n-3 HUFA had highest weight gain (WG) and specific growth rate (SGR), and the feed conversion ratio (FCR) showed the minimum at the same level. Shrimp muscle fatty acid profiles reflected that of diet. The contents of triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in serum decreased along with n-3 HUFA levels increasing. The activity of superoxide dismutase (SOD) in hepatopancreas was highest significantly at the level of 0.86 % n-3 HUFA group than that in other groups. The content of malondialdehyde (MDA) in hepatopancreas increased with the increasing of n-3 HUFA levels, which reached the maximum value in 1.97 % group and was significantly higher than that in control group. The levels of n-3 HUFA could obviously affect on the cell morphology and lipid deposition in hepatopancreas of L. vannamei. Results of this study suggested that shrimp fed moderate dietary n-3 HUFA could enhance growth, feed utilization, antioxidant capacity and reduces excess lipid deposition.