Spirulina platensis powder is an applicable feed additive for Chinese horseshoe crab Tachypleus tridentatus

The development of artificial feeds for Tachypleus tridentatus is important given the requirement of Tachypleus amebocyte lysate and the temporary rearing and industrial aquaculture. The effects of Spirulina platensis powder on growth performance, haemolymph biochemical parameter and non-specific immune enzymes were investigated. Addition of S. platensis powder improved artificial feed quality for growth performance. Haemocyanin concentration, total protein and total cholesterol (TCH) did not differ among the groups after 4 weeks of feeding natural feeds. TCH in Treatment 1 decreased significantly after 2 weeks, but this phenomenon was resolved by the addition of S. platensis powder. Total antioxidant, superoxide dismutase and catalase decreased with varying degrees in the groups of semi-artificial feed within the first 2 weeks, but the parameters converged after 4 weeks. Malonaldehyde increased after 4 weeks with the addition of S. platensis powder to semi-artificial feed. Groups with semi-artificial feed had similar contents of acid phosphatase and alkaline phosphatase to those of the group with natural feed. Thus, no differences were found among groups during the 4 weeks. S. platensis powder not only had physiological stimulative effects but also increased the growth of the adult Chinese horseshoe crab T. tridentatus when the crabs were fed with semi-artificial feed. The powder also stabilized the haemolymph biochemical parameters and non-specific immune enzymes. Therefore, the effects of S. platensis powder as feed additive on the adult T. tridentatus were evaluated. This study provides first-hand data for the development of artificial feeds and generates positive results for T. tridentatus.