Shengming Sun

Molecular Cloning, Characterization, and mRNA Expression of Hemocyanin Subunit in Oriental River Prawn Macrobrachium nipponense

Hemocyanin is a copper-containing protein with immune function against disease. In this study, a hemocyanin subunit named MnHc-1 was cloned from Macrobrachium nipponense. The full-length cDNA of MnHc-1 was 2,163 bp with a 2,028-bp open reading frame (ORF) encoding a polypeptide of 675 amino acids. The MnHc-1 mRNA was expressed in the hepatopancreas, gill, hemocytes, intestine, ovary, and stomach, with the highest level in the hepatopancreas. In the infection trial, the MnHc-1 mRNA transcripts in the hemocytes were significantly downregulated at 3 h after injection of Aeromonas hydrophila and then upregulated at 6 h and 12 h, followed by a gradual recovery from 24 to 48 h. The MnHc-1 transcriptional expression in the hepatopancreas was measured after M. nipponense were fed seven diets with 2.8, 12.2, 20.9, 29.8, 43.1, 78.9, and 157.1 mg Cu kg−1 for 8 weeks, respectively. The level of MnHc-1 mRNA was significantly higher in the prawns fed 43.1–157.1 mg Cu kg−1 diet than in that fed 2.8–29.8 mg Cu kg−1 diet. This study indicated that the MnHc-1 expression can be affected by dietary copper and the hemocyanin may potentially participate in the antibacterial defense of M. nipponense.

Effect of Copper-Enriched Artemia on Growth, Body Composition, Antioxidant Enzyme Activities, and Osmotic Stress Tolerance of Chinese Mitten Crab Eriocheir sinensis Larvae

ABSTRACT Feeding trials were carried out to determine the effects of Cu supplementation in Artemia on growth, antioxidant enzyme activity, and osmotic stress tolerance of the Chinese mitten crab (Eriocheir sinensis) larvae. The crab at zoea stage 3 were fed with 4 types of Artemia nauplii enriched with 0 mg Cu/mL (control), 0.1 mg Cu/mL (treatment 1), 0.2 mg Cu/mL (treatment 2), and 0.4 mg Cu/mL (treatment 3), respectively. Although Cu enrichment did not enhance the survival rate significantly, crab megalopa fed Artemia in treatments 1 and 2 showed greater body weight and larval stage index than those in the control group. The levels of Cu in Artemia affected significantly the crude lipid content and major fatty acid composition in megalopa. The superoxide dismutase and catalase activity of the megalopa in treatment 3 were greater than those in the meglopa fed Artemia enriched with other levels of Cu. The ability to tolerate salinity stress in megalopa in treatments 1 and 2 was also improved in comparison with the control and treatment 3 groups. This study demonstrates that the level of Cu at 33–52 µg/g dry matter in A. nauplii is required to improve the growth, salinity tolerance, and antioxidant ability of E. sinensis larvae.