Chlorella meal is a potential protein source for aquafeeds. However, the physiological response of carnivorous fish fed Chlorella meal remains elusive. This study evaluated the effects of replacing dietary fish meal with Chlorella meal on growth performance, pigmentation, and liver health in largemouth bass. Five diets were formulated to replace dietary fish meal of 0% (C0, control), 25% (C25), 50% (C50), 75% (C75), and 100% (C100) with Chlorella meal, respectively. Total 300 fish (17.6 ± 0.03 g) were randomly assigned to 15 tanks (3 tanks/group). Fish were fed the experimental diet twice daily for 8 weeks. The increased dietary Chlorella meal quadratically influenced the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), and feed intake (FI), which were significantly lower in the C100 group than in the other groups (P < 0.05). The feed conversion ratio (FCR) increased linearly or quadratically with dietary Chlorella meal. Dietary Chlorella meal linearly or quadratically increased the lutein content of plasma, liver, and dorsal muscle of largemouth bass (P < 0.05). Compared to the C0 group, all supplemented Chlorella meal groups significantly improved the yellowness (b∗) of the dorsal body (1.5 to 2.0 fold), abdominal body (1.5 to 1.8 fold), and dorsal muscle (3.8 to 5.4 fold) of largemouth bass (P < 0.05). In addition, compared to the C0 group, the liver vacuolation area of fish was significantly increased in the C75 and C100 groups (P < 0.05). Transcriptional levels of apoptosis-related genes of β-cell lymphoma-2 (bcl2), caspase-9-like (casp9), and caspase-3a (casp3) were markedly upregulated (0.9 to 1.6 fold) in the C100 group compared to the C0 group (P < 0.05). Based on the quadratic regression analysis between FBW, WGR, or SGR and dietary Chlorella meal level, largemouth bass had the best growth when replacing 31.7% to 32.6% of fish meal with 15.03% to 15.43% dietary Chlorella meal. The present results indicated that dietary supplementation with Chlorella meal (11.85% to 47.45%) significantly enhanced the pigmentation; however, total replacement of fish meal (40%) with Chlorella meal (47.45%) caused growth retardation, apoptosis, and liver damage in largemouth bass.

小球藻粉是水产饲料的潜在蛋白质来源。然而，食肉鱼喂食小球藻粉的生理反应仍然难以捉摸。本研究评估了用小球藻粉代替膳食鱼粉对大口黑鲈生长性能、色素沉着和肝脏健康的影响。配制了五种日粮，分别用小球藻粉替代 0%（C0，对照）、25%（C25）、50%（C50）、75%（C75）和 ​​100%（C100）的日粮鱼粉。总共 300 条鱼 (17.6 ± 0.03 g) 被随机分配到 15 个鱼缸（3 个鱼缸/组）。每天两次给鱼喂食实验饲料，持续 8 周。增加的膳食小球藻膳食对最终体重（FBW）、增重率（WGR）、比生长率（SGR）和采食量（FI）呈二次方影响，C100组显着低于其他组（P  < 0.05） . 饲料转化率 (FCR) 随日粮小球藻粉呈线性或二次方增加。日粮小球藻粉线性或二次增加大口黑鲈血浆、肝脏和背肌的叶黄素含量（P  < 0.05）。与 C0 组相比，所有补充小球藻粉组均显着改善了大嘴的背体（1.5 至 2.0 倍）、腹体（1.5 至 1.8 倍）和背肌（3.8 至 5.4 倍）的黄色度（b*）低音 ( P < 0.05)。此外，与C0组相比，C75组和C100组鱼的肝空泡化面积显着增加（P  < 0.05）。与 C100 组相比，C100 组β 细胞淋巴瘤 2 ( bcl2 ) 、 caspase-9-like ( casp9 )和caspase-3a ( casp3 ) 凋亡相关基因的转录水平显着上调（0.9 至 1.6 倍）。 C0 组（P  < 0.05）。基于 FBW、WGR 或 SGR 与日粮小球藻粉水平的二次回归分析，当用 15.03% 至 15.43% 的日粮小球藻替代 31.7% 至 32.6% 的鱼粉时，大口黑鲈的生长最好一顿饭。目前的结果表明，膳食补充小球藻粉（11.85% 至 47.45%）显着增强了色素沉着；然而，用小球藻粉 (47.45%)完全替代鱼粉 (40% ) 会导致大口黑鲈的生长迟缓、细胞凋亡和肝损伤。