Growth, calcium content, proximate composition, and fatty acid composition of triangle sail mussel (Hyriopsis cumingii) fed five different microalgal diets

Abstract

Sustainable cultivation of triangle sail mussel Hyriopsis cumingii lacks a suitable, optimal diet. To determine the optimum microalgal diet H. cumingii, we tested five microalgal diets (Cyclotella sp., Chlorella pyrenoidosa, Scenedesmus dimorphus, Monoraphidium contortum, and a mix of these four microalgae) using single factor experiments. We measured body growth, pearl growth, proximate composition, fatty acid composition, and calcium (Ca) content in the mantle and foot of H. cumingii. Overall, diet had significant effects on the growth of H. cumingii (P < .05), and the group fed Cyclotella sp. showed the greatest (P < .05) increases in weight, shell length, height, and width, and pearl weight. The Ca content of the mantle and foot also differed significantly between treatments (P < .05); the highest content in the foot was observed in mussels fed Cyclotella sp., while the highest content in the mantle was found in mussels fed S. dimorphus and M. contortum. The crude protein contents of the foot and mantle were highest in mussels fed Cyclotella sp., and both were positively correlated with growth; the moisture content of the foot was negatively correlated with growth. The mussels fed the mixed microalgae had the highest polyunsaturated fatty acids (PUFAs) proportion (P < .05), while the group fed Cyclotella sp. showed the lowest PUFAs and the highest saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) proportions (P < .05). The proportions of SFAs and MUFAs were positively correlated with growth, and the proportion of PUFAs was negatively correlated with growth. Principal component analysis showed that the fatty acid composition differed among diet groups. In summary, mussels showed different growth, Ca content, and proximate and fatty acid compositions when fed different microalgal diets. Cyclotella sp. was the optimum microalgal diet, followed by S. dimorphus. Based on growth rate and tissue compositions of H. cumingii obtained here, a suitable diet for this species should include these microalgae.