The study was conducted to investigate the effects of fish protein hydrolysate (FPH) in diets for turbot on growth performance, muscle fibre morphometry, and the expression of muscle growth‐related genes. A control diet (FPH0) contained 0 g/kg FPH, and four experimental diets were formulated replacing fishmeal with FPH at levels of 45 (FPH4.5), 120 (FPH12), 180 (FPH18) and 300 (FPH30) g/kg. Fish fed the FPH12 and FPH18 diets had higher specific growth rate (SGR) than fish fed the FPH0 diet (p < .05), and a quadratic regression was found between SGR and dietary FPH level (p = .001, R² = .677). Cross‐section area (CSA) and the length of sarcomere in the FPH12 group increased compared with the control group (p < .05), and a quadratic regression was observed between CSA and dietary FPH level (p = .006, R² = .574) and between sarcomere length and dietary FPH level (p = .018, R² = .788). An appropriate level of FPH down‐regulated myostatin 2 gene expression and up‐regulated proliferating cell nuclear antigen gene expression, while the expression of myogenic regulatory factors was not affected by dietary treatments (p > .05). To conclude, an appropriate level of FPH may improve muscle growth by regulating the expression of muscle growth‐related genes, and muscle microstructure and ultrastructure.

中文翻译：

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大菱t日粮中的鱼蛋白水解物影响肌肉纤维形态以及与肌肉生长相关的基因的表达

这项研究旨在研究日粮中大鱼turbo的鱼蛋白水解物（FPH）对生长性能，肌肉纤维形态学以及肌肉生长相关基因表达的影响。对照饮食（FPH0）包含0 g / kg FPH，并配制了四种实验饮食，分别以45（FPH4.5），120（FPH12），180（FPH18）和300（FPH30）g / kg的水平代替鱼粉。饲喂FPH12和FPH18日粮的鱼比饲喂FPH0日粮的鱼具有更高的比生长速率（SGR）（p  <.05），并且SGR和日粮FPH水平之间存在二次回归（p  = .001，R ²  =）。 677）。与对照组相比，FPH12组的横截面积（CSA）和肌节长度增加（p <0.05），和CSA和膳食FPH水平（之间观察到二次回归p  = 0.006，[R ²  = 0.574）和肌节长度和膳食FPH水平（之间p  = 0.018，[R ²  = 0.788）。适当水平的FPH下调myostatin 2基因表达并上调增殖细胞核抗原基因表达，而成肌调节因子的表达不受饮食治疗的影响（p  > .05）。总之，适当水平的FPH可以通过调节与肌肉生长相关的基因的表达以及肌肉的微结构和超微结构来改善肌肉的生长。