Effects of light intensity on growth performance, biochemical composition, fatty acid composition and energy metabolism of Scylla paramamosain during indoor overwintering

Abstract

A long-term experiment was carried out to explore the effects of light intensity on growth performance, biochemical composition, fatty acid composition and energy metabolism of Scylla paramamosain. S. paramamosain were cultured under three illumination levels (0, 1.43 and 40.31 μmol m−2 s−1) in a recirculating water system of crab compartments for four months. S. paramamosain were fed to satiation once daily (17:00). The photoperiod was set at 10 L: 14 D (07:00–17:00). Results showed that the best growth of S. paramamosain was observed at the 1.43 μmol m−2 s−1 light intensity. The amount of energy substances was higher at the 1.43 μmol m−2 s−1 and 40.31 μmol m−2 s−1 light intensities. The amount of total unsaturated fatty acids (∑UFA) and total polyunsaturated fatty acids (∑PUFA) was significantly higher at the 1.43 μmol m−2 s−1 and 40.31 μmol m−2 s−1 light intensities (p < 0.05). However, total saturated fatty acids (∑SFA) were significantly higher at 0 μmol m−2 s−1 (p < 0.05). The concentrations of hepatic glycogen, blood glucose (GLU), total cholesterol (T-CHO) and triglyceride (TG) were significantly elevated at the 1.43 μmol m−2 s−1 light intensity, whereas the highest concentrations of muscle glycogen and lactic acid (LD) were at the 40.31 μmol m−2 s−1 light intensity (p < 0.05). Activities of hexokinase (HK) and pyruvate kinase (PK) were markedly higher at the 40.31 μmol m−2 s−1 light intensity, while the highest lactic dehydrogenase (LDH) activity was observed at 0 μmol m−2 s−1 and at 1.43 μmol m−2 s−1 for succinate dehydrogenase (SDH) (p < 0.05). Compared with 0 μmol m−2 s−1 and 40.31 μmol m−2 s−1, 1.43 μmol m−2 s−1 was more suitable for the breeding of S. paramamosain.