The effects of feed deprivation were evaluated for 1 week and 2 weeks in Lutjanus guttatus juveniles. A significant reduction in body mass was observed in both feed deprivation schemes, as well as in hepatosomatic, viscerosomatic and mesenteric fat indexes. The composition of fasted fish was characterized by a decrease in lipid content; the liver displayed an intense reduction of lipid reserves in both fasted groups, and increased expression of the lysosomal acid lipase. 1 week after re-feeding, both experimental groups showed an increase in specific growth rate, feed intake and feed conversion ratio. A recovery in hepatic lipid reserves was observed, and the expression of the lysosomal acid lipase decreased, although lipid content in both groups was still significantly lower than in control groups. Hepatic expression of the growth hormone receptor decreased after fasting, and remained low even after the fish were fed, whereas the expression of insulin-like growth factor 1 and 2 increased after fasting and decreased in both groups when fish were fed again. Altogether, these results showed a partial compensatory growth response in L. guttatus juveniles after fasting, with enhanced growth rates and improved feed efficiency. Fish used stored lipid reserves as the main energy source, and the expression of growth-related and lipid mobilization marker genes in the liver showed similar patterns in both fasting schemes. Based on the results, we suggest as much as 1-week fasting intervals during grow-out programmes to reduce visceral fat and increase growth rate in this species.

中文翻译：

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限制饲料对玫瑰斑鲷 (Lutjanus guttatus) 生长性能、脂质动员和基因表达的影响

在 Lutjanus guttatus 幼鱼中评估了 1 周和 2 周的饲料剥夺的影响。在两种饲料剥夺方案以及肝体、内脏和肠系膜脂肪指数中都观察到体重显着降低。禁食鱼的组成特点是脂质含量减少；两个禁食组的肝脏都显示出脂质储备显着减少，溶酶体酸性脂肪酶的表达增加。重新饲喂1周后，两个实验组均表现出比生长率、采食量和饲料转化率的增加。观察到肝脏脂质储备恢复，溶酶体酸性脂肪酶的表达降低，尽管两组的脂质含量仍显着低于对照组。禁食后肝脏生长激素受体的表达降低，即使在喂食鱼后仍保持低水平，而禁食后胰岛素样生长因子 1 和 2 的表达增加，再次喂鱼时两组的表达均下降。总而言之，这些结果表明，L. guttatus 幼鱼在禁食后出现了部分补偿性生长反应，生长速度加快，饲料效率提高。鱼类使用储存的脂质储备作为主要能量来源，肝脏中生长相关和脂质动员标记基因的表达在两种禁食方案中表现出相似的模式。根据结果​​，我们建议在养成计划期间最多间隔 1 周禁食，以减少该物种的内脏脂肪并提高其生长速度。而胰岛素样生长因子 1 和 2 的表达在禁食后增加，而在再次喂鱼时两组均减少。总而言之，这些结果表明，L. guttatus 幼鱼在禁食后会出现部分补偿性生长反应，生长速度加快，饲料效率提高。鱼类使用储存的脂质储备作为主要能量来源，肝脏中生长相关和脂质动员标记基因的表达在两种禁食方案中表现出相似的模式。根据结果​​，我们建议在养成计划期间最多间隔 1 周禁食，以减少该物种的内脏脂肪并提高其生长速度。而胰岛素样生长因子 1 和 2 的表达在禁食后增加，而在再次喂鱼时两组均减少。总而言之，这些结果表明，L. guttatus 幼鱼在禁食后会出现部分补偿性生长反应，生长速度加快，饲料效率提高。鱼类使用储存的脂质储备作为主要能量来源，肝脏中生长相关和脂质动员标记基因的表达在两种禁食方案中表现出相似的模式。根据结果​​，我们建议在养成计划期间最多间隔 1 周禁食，以减少该物种的内脏脂肪并提高其生长速度。这些结果表明，L. guttatus 幼鱼在禁食后出现了部分补偿性生长反应，生长速度加快，饲料效率提高。鱼类使用储存的脂质储备作为主要能量来源，肝脏中生长相关和脂质动员标记基因的表达在两种禁食方案中表现出相似的模式。根据结果​​，我们建议在养成计划期间最多间隔 1 周禁食，以减少该物种的内脏脂肪并提高其生长速度。这些结果表明，L. guttatus 幼鱼在禁食后出现了部分补偿性生长反应，生长速度加快，饲料效率提高。鱼类使用储存的脂质储备作为主要能量来源，肝脏中生长相关和脂质动员标记基因的表达在两种禁食方案中表现出相似的模式。根据结果​​，我们建议在养成计划期间最多间隔 1 周禁食，以减少该物种的内脏脂肪并提高其生长速度。