Effects of single‐species microalgae diet on accumulation of lipid and carotenoid and expression of lipid‐related genes in Nan'ao Golden ScallopChlamys nobilis

Abstract

Nan'ao Golden Scallop, Chlamys nobilis, is an important scallop species in aquaculture and is rich in lipids and carotenoid. Previous studies have shown that microalgae diet has a significant effect on the accumulation of total lipid content (TLC) and total carotenoid content (TCC) in bivalves. However, the effects of single-species microalgae diet on accumulation of TLC and TCC at molecular level are unclear. In this study, we used C. nobilis as a bivalve animal model to assess the effects of single-species microalgae diet (Tetraselmis subcordiformis, Dicrateria zhanjiangensis and Chaetoceros mulleri) on the accumulation of lipids and carotenoids, and the expression of stearoyl-CoA desaturase (SCD) and scavenger receptor class B-like-3 (SRB-like-3) genes in C. nobilis. The results of this study indicated that high lipid microalgae diet promoted the accumulation of TCC in C. nobilis tissues. The expression of SCD and SRB-like-3 genes was highly affected by the lipid composition of diet, in which high expression of SCD and SRB-like-3 genes was correlated with low C16:1n-9 and/or C18:1n-9t and/or C16:1/C16:0 and/or C18:1/C18:0. In intestine and adductor muscle, the expression of SCD gene was positively correlated with accumulation of TCC, TLC and fatty acid content, suggesting that SCD gene may indirectly promote the accumulation of TCC (lipid soluble) by promoting lipid accumulation. For SRB-like-3 gene, the high expression of SRB-like-3 was only correlated to the high TCC in intestine, suggesting that SRB-like-3 may be a candidate gene for carotenoid absorption in C. nobilis and has nothing to do with the transport or accumulation of carotenoid. The findings of this study are of great significance for further understanding how microalgae diet affects the accumulation of TCC and TLC, and the expression of lipid-related genes in bivalves.