Effects of oxidized fish oil on digestive enzyme activity and antioxidant system in Macrobrachium rosenbergii post-larvae

Abstract

Lipids are essential nutrients for animal. Oxidized lipid might induce injury stress for prawns. This study was conducted to evaluate the oxidized fish oil on growth, digestive enzymes activities, antioxidant system of giant freshwater prawn (Macrobrachium rosenbergii) post-larvae for 21 days with the initial body weight of 1.13 ± 0.04 mg. Three trial diets were with fed the basal diet (C), basal diet supplemented 4% fish oil (4F), basal diet supplemented 4% oxidized fish oil (4OF), respectively (feeding 0 d, 7 d and 14 d, denoted as T7, T14 and T21, respectively). The results showed that the final body weight (FBW) and weight gain ratio (WGR) was increased in the group of 4F and decreased in the group of 4OF. After feeding fish oil or oxidized fish oil, the proteinase activity of T14, T21 post-larvae in 4OF group was significantly higher than T7 post-larvae (P < 0.05). And the lipase activity of T21 post-larvae was significantly higher than T7 post-larvae in 4OF group (P < 0.05). The amylase activity of T21 post-larvae in C, 4F and 4OF groups was significantly higher than T7 and T14 post-larvae (P < 0.05). What’s more, at T14 post-larvae, proteinase activity in 4OF was significantly higher than those in C and 4F (P < 0.05). T-SOD, GSH-Px and MDA of T21 post-larvae was significantly increased in 4OF (P < 0.05). Besides, at T14 post-larvae, GSH-Px in 4F, MDA in 4OF was significantly increased compared with the control group (P < 0.05). Furthermore, the mRNA expression of IMD, Relish, IκBα, Dorsal, and Toll were significantly affected by oxidized fish oil (P < 0.05). In conclusion, this study indicated that dietary oxidized fish oil could induce oxidative stress, inhibit growth performance, change the digestive enzymes activities and influence the antioxidant system of M. rosenbergii post-larvae.