To investigate the effects of dietary astaxanthin on fish growth and body color, blood parrotfish juveniles were assigned to three groups: control (CL), fed a diet without astaxanthin supplementation for 12 weeks; coloration (ASTA+), fed a diet containing 0.45 g/kg astaxanthin for 12 weeks; decoloration (ASTA-) fed the diet supplemented with astaxanthin for the first six weeks and then the control diet for the other six. Our results showed that the specific growth rate showed no significant difference between ASTA+ and CL at weeks 3 and 6 and among ASTA+ , ASTA- and CL at weeks 9 and 12. The ASTA+ group showed higher skin redness at weeks 3, 6, 9 and 12 and higher yellowness at weeks 6, 9 and 12 than CL, and than ASTA- at week 12. The ASTA+ group had higher concentrations of astaxanthin, HDL-C and LDL-C than the CL at weeks 3, 6, 9, and 12 and than ASTA- group at weeks 9 and 12. By compared ASTA+ and ASTA- with CL, a total of 4250 differentially expressed genes (DEGs) were detected. Pathways, e.g., PPRA signaling pathway, fatty acid degradation, and ABC transporters, of DEGs involved in carotenoid deposition were enriched. DEGs involved in the absorption and transport (e.g., upregulated lpl and pltp, and downregulated stard7), metabolism (e.g., upregulated adh1 and dhrs7cb, and downregulated cyp7b1, dhrs11, and si:ch211-113j14.1), and deposition of carotenoids (e.g., downregulated apoa1b and apodb) might be associated with skin coloration. Overall, the results of this study could help to understand the biochemical and molecular mechanism of body coloration under the presence and absence of dietary astaxanthin in blood parrotfish.

为了研究日粮虾青素对鱼类生长和体色的影响，将血鹦嘴鱼幼鱼分为三组：对照组（CL），喂食不添加虾青素的饲料 12 周；着色（ASTA+），喂食含有 0.45 g/kg 虾青素的饮食 12 周；脱色（ASTA-）在前六周喂食添加虾青素的饮食，然后在其他六周喂食对照饮食。我们的结果表明，ASTA+ 和 CL 在第 3 周和第 6 周以及 ASTA+、ASTA-和 CL 在第 9 周和第 12 周时的比生长率没有显着差异。ASTA+ 组在第 3、6、9 周和在第 12 周，第 6、9 和 12 周的黄色度高于 CL，在第 12 周时高于 ASTA-。ASTA+ 组在第 3、6、9 周时的虾青素、HDL-C 和 LDL-C 浓度高于 CL，在第 9 周和第 12 周，ASTA+ 和 ASTA- 与 CL 比较，共检测到 4250 个差异表达基因 (DEG)。参与类胡萝卜素沉积的 DEG 的通路，例如 PPRA 信号通路、脂肪酸降解和 ABC 转运蛋白被富集。参与吸收和运输的 DEG（例如，上调lpl和pltp以及下调的 stard7）、新陈代谢（例如，上调的 adh1和dhrs7cb，以及下调的 cyp7b1、dhrs11和si:ch211-113j14.1）和类胡萝卜素的沉积（例如，下调的apoa1b和apodb）可能与肤色。总体而言，这项研究的结果有助于了解血鹦嘴鱼在食用虾青素存在和不存在情况下体色的生化和分子机制。