Effects of dietary lipid sources on the growth, gonad development, nutritional and organoleptic quality, transcription of fatty acid synthesis related genes and antioxidant capacity during cold storage in adult sea urchin (Strongylocentrotus intermedius)

Abstract

A 42-day feeding trial was carried out to investigate the effects of effects of five formulated feeds with different lipid sources (colza oil (CO), fish oil (FO), linseed oil (LO), soybean oil (SO), or palm oil (PO)) and kelp (Laminaria japonica) on the growth, gonad development, nutritional and organoleptic quality, transcription of fatty acid synthesis related genes, and antioxidant capacity during cold storage in adult sea urchin (Strongylocentrotus intermedius). Each diet was randomly allocated to 12 cages of sea urchins (initial weight: 60.76 ± 1.21 g). The results showed that the weight gain rate (WGR) in FO treatment was comparable to the CO and kelp, but was significantly higher than the PO, SO and LO. The WGR of S. intermedius fed SO and LO was significantly lower than that in the other dietary treatments. S. intermedius fed kelp had a significantly lower gonadosomatic index (GSI) than those fed the formulated feeds. The GSI of S. intermedius fed SO was comparable to that of sea urchins fed LO but was significantly lower than that of sea urchins fed FO, PO and CO. The percentage of gonads with market acceptable colors was highest in the PO treatment, followed by CO, FO and kelp, with the lowest value observed in SO and LO. The hardness of gonads in S. intermedius fed LO was comparable to that fed kelp, CO, and PO, but was significantly higher than that fed FO and SO. The total amino acid (AA), total sweet AA, and total umami AA were highest in the gonads of kelp treatment, which were only significantly higher than those in FO. FO contributed to the highest content of long-chain polyunsaturated fatty acids (LC-PUFAs) and ratio of EAA/TAA in the gonads. S. intermedius fed SO and LO had relatively higher ARA and EPA than the other plant oils, which could be due to the elevated transcription of fatty acid synthesis related genes. During cold storage (6–36 h), the MDA content in the gonads of S. intermedius fed FO was significantly higher than that in the other dietary treatments. In conclusion, PO and CO were most ideal lipid sources based on the growth, gonad increase and organoleptic characteristics. Although FO resulted in the highest nutritional value, it was most easily oxidized during cold storage. These results could contribute to adopting an effective and efficient feeding strategy to produce high quantity and quality gonads for adult S. intermedius.