ScholarWorks@경상국립대학교

초록

This study evaluated the effects of replacing fish meal (FM) with stalked sea squirt ( Styela clava ) tunic (TSC) on growth performance, health status, and skin pigmentation in juvenile red sea bream ( Pagrus major ). Five isonitrogenous and isolipidic diets were formulated, with TSC replacing FM at 0 % (TSC0), 5 % (TSC5), 10 % (TSC10), 15 % (TSC15), and 20 % (TSC20). After an 8-week feeding trial, TSC inclusion up to 10 % did not adversely affect growth, whereas TSC15 and TSC20 significantly reduced weight gain and feed efficiency. Immune response indicators, including lysozyme activity, immunoglobulin M, and interleukin-1, exhibited a linear decline with increasing dietary TSC levels ( P < 0.05), suggesting potential immunosuppressive effects at higher inclusion rates. Skin color analysis revealed linear increases in redness (a*) and yellowness (b*) with higher dietary TSC levels. TSC15 significantly enhanced cranial skin a* and b* values compared to TSC0, although differences from TSC5, TSC10, and TSC20 were not significant. These results indicate that TSC can replace up to 10 % of FM in juvenile P. major diets without compromising growth or health, while higher replacement levels enhance skin pigmentation but may entail trade-offs in immune function and nutritional performance.

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