Effects of dietary lipid content on growth, body composition and pigmentation of large yellow croaker Larimichthys croceus

Abstract

Abstract A 60-day experiment was conducted to investigate the effects of dietary lipid content on the growth performance and pigmentation of large yellow croaker Larimichthys croceus . Six isonitrogenous (44% crude protein) diets containing 75 mg/kg of astaxanthin were formulated to have graded contents of lipid (2.7, 5.1, 8.6, 11.7, 14.9 and 18.1%, respectively). Each diet was fed to triplicate groups of fish (initial weight: 10.02 ± 0.02 g). The results showed that the survival rate (SR) was not significantly affected by dietary lipid contents. Fish fed with 2.7% of dietary lipid had the lowest weight gain rate (WGR). The highest value was found in fish fed diets with 11.7% of lipid. Lightness ( L *) in the ventral skin was higher than that in the dorsal skin. There were no significant differences in redness ( a ⁎ ) or lightness among all treatments in both ventral and dorsal skin. Meanwhile, ventral skin yellowness was improved with increasing the dietary lipid content up to 11.7%. Carotenoid and melanin contents in the dorsal skin were not significantly affected by dietary lipid content. Carotenoids content in the ventral skin improved with increasing dietary lipid content up to 14.9%. High correlation was found between yellowness and the carotenoids content in the ventral skin. The minimum dietary lipid requirement was estimated to be 10.42% for growth. For skin pigmentation, this requirement was estimated to be 12.00% and 13.19% for ventral skin yellowness and carotenoids content, respectively.