Interval feeding of CpG ODN ‐supplemental diets enhanced growth in juvenile Chinese mitten crab, Eriocheir sinensis

Abstract

CpG oligodeoxynucleotides (CpG ODNs) activate the immune system and act as an immunopotentiator against infectious diseases in aquatic animals, but the growth-promoting effect of CpG ODN was rarely reported in crustaceans. In the present study, CpG ODN (40 mg kg−1) was supplemented into the basic diet, and three feeding strategies including interval CpG ODN feeding (CI group), continuous CpG ODN feeding (CC group) and basic diet feeding (B group) were performed in Chinese mitten crab, Eriocheir sinensis. After 4 weeks of feeding, the weight gain and specific growth rate in CI group were significantly higher (p < 0.05) than that of CC group and B group. The moulting rate of CI group was also highest in CI group and lowest in CC group. Meanwhile, the alkaline phosphatase activity and Ca2+ concentration that related to the shell formation, the amylase and pepsin activities on 14th day in CI group were all higher compared to other two groups. The glucose and glycogen values kept a relative high level from 14th day to 28th day in CI group compared to that in B group and CC group. In addition, the numbers of intestine fold and villus height were significantly higher (p < 0.05) than that of B group and CC group. More microvillus numbers, branches and goblet cells were observed in CI group. Taken together, these results demonstrated that the interval feeding strategy of CpG ODN supplemental diets probably promoted growth and might be a candidate strategy in the application of crab aquaculture.