Gonadal maturation in Litopenaeus vannamei fed on four different polychaetes

Abstract Broodstock culture of Litopenaeus vannamei plays an important role in the shrimp culture industry; thus, a nutritional and bio-safety food for broodstock culture is necessary. Marine polychaetes, which have a good nutritional content, are an essential and widely used live food in the current shrimp industry. In this study, four polychaete species, Marphysa maxidenticulata, Cheilonereis cyclurus, Nereis vexillosa, and Perinereis aibuhitensis, were fed to broodstock of L. vannamei as the only food, and the gonadal maturity parameters of the broodstock were examined. The results showed that broodstock, which were fed with M. maxidenticulata, had the highest gonadal maturation rate (56.67%). The N. vexillosa food group had the highest gonadal index (5.37%). The content of serum progesterone and vitellogenin (VTG) was highest in the broodstock fed N. vexillosa. The expression of VTG mRNA in the gonads was also highest in the broodstock fed N. vexillosa, followed by those fed M. maxidenticulata. Nutritional content analysis showed that lipid content in the four worms ranged from 13% to 22%. The content of polyunsaturated fatty acids was highest in N. vexillosa, particularly C18:2 n-6, C18:3 n-3, C20:4 n-6, and C20:5 n-3. In addition, the 20:5 n-3 content in N. vexillosa was 2.5–8.0 times higher than that in the other polychaetes. These results indicated that polychaetes had different effects on promoting the gonadal maturation of L. vannamei. N. vexillosa and M. maxidenticulata could be potential live food to promote the gonadal maturation of L. vannamei.