Dietary fishmeal substitution with Antarctic krill meal improves the growth performance, lipid metabolism, and health status of oriental river prawn (Macrobrachium nipponense)

Abstract

Aims to assess the effects of dietary inclusion of Antarctic krill meal (KM), five experimental diets supplemented with graded levels of KM (0 %, FM; 5 %, KM5; 10 %, KM10; 15 %, KM15; 20 %, KM20; 0 %, 13.3 %, 26.7 %, 40.0 %, and 56.7 % replacement fishmeal levels, respectively), were prepared to feed oriental river prawn (Macrobrachium nipponense) (0.20 ± 0.01 g) for 8 weeks. The results revealed significant improvements in weight gain rate (WGR), specific growth rate (SGR), feed conversion rate (FCR), and protein efficiency ratio (PER) at the inclusion of 5 %-20 % KM (P < 0.05). In the KM10 and KM15 groups, the concentrations of hemolymph total protein (TP), albumin (ALB), triglycerides (TG), high-density lipoprotein (HDL), and hepatopancreatic glutathione (GSH) were observed to be significantly higher compared to the FM group (P < 0.05). Conversely, the contents of hepatopancreatic malondialdehyde (MDA), total nitric oxide synthase (TNOS), and inducible nitric oxide synthase (iNOS) were significantly lower in the KM10 and KM15 groups compared to the FM group (P < 0.05). The mRNA expression levels of dorsal protein (dorsal), heat shock protein 60 (hsp60), and myeloid differentiation factor 88 (myd88) in the hepatopancreas in the KM10 group exhibited the lowest level. Additionally, compared to the FM group, the expression levels of fatty acid synthase (fas) and acetyl CoA carboxylase (acc) were significantly upregulated (P < 0.05), while the acyl CoA bindingprotein (acbp), carnitine palmitoyltransferase I (cpt I), and scavenger receptor B I (sr-b I) were significantly downregulated in the KM10 group (P < 0.05). In addition, the results of histopathology sections showed that 5–15 % KM could improve the health status of hepatopancreas and was a safe alternative to fishmeal. Overall, the optimal KM inclusion level in feed was 12.96 % (substituting for 34.60 % fishmeal) based on the quadratic fitting curve calculations of WGR and SGR.

Keywords

• Macrobrachium nipponense
• Antarctic krill meal
• Growth performance
• Antioxidant capacity
• Lipid metabolism