He Zhimin, Cai Yuyang, Xiao Yang, Cao Shenping, Zhong Gaode, Li Xinting, Li Yanfang, Luo Junhan, Tang Jianzhou, Qu Fufa, Liu Zhen, Liu Suchun
Hunan Provincial Key Laboratory of Nutrition and Quality Control of Aquatic Animals, College of Biological and Chemical Engineering, Changsha University, Changsha 410022, China.
College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Int J Mol Sci. 2023 Jul 27;24(15):12043. doi: 10.3390/ijms241512043.
The aim of this study is to investigate the effect of dietary protein levels on flesh quality, oxidative stress, and autophagy status in the muscles of triploid crucian carp (), and the related molecular mechanisms. Six experimental diets with different protein levels (26%, 29%, 32%, 35%, 38%, 41%) were formulated. A total of 540 fish with an initial weight of 11.79 ± 0.09 g were randomly assigned to 18 cages and six treatments with three replicates of 30 fish each for 8 weeks feeding. It could be found that the whole-body ash content significantly increased in high protein level groups ( < 0.05). The 29% dietary protein level group exhibited the highest muscle moisture, although there was an inconspicuous decrease in the chewiness of the muscles when compared with the other groups. The dietary protein level influenced the content of free amino acids and nucleotides, especially the content of flavor amino acids, which exhibited an increasing tendency along with the increasing protein level, such as alanine and glutamic acid, while the flavor nucleotides showed different fluctuation trends. Moreover, the genes related to muscle development were shown to be influenced by the dietary protein level, especially the expression of , which was up-regulated with the increasing dietary protein levels. The 29% dietary protein level promoted the majority of analyzed muscle genes expression to the highest level when compared to other dietary levels, except the , whose expression reached its highest at 38% dietary protein levels. Furthermore, the effect of dietary protein levels on antioxidant signaling pathway genes were also examined. High protein levels would boost the expression of ; and mRNA expression showed the highest level at the 32% dietary protein group. The increasing dietary protein level decreased both mRNA and protein expressions of Nrf2 by up-regulating . Autophagy-related gene expression levels reached the peak at 32% dietary protein level, as evidenced by a similar change in protein expression of FoxO1. In summary, muscle nutritional composition, antioxidative pathways, and autophagy levels were affected by the dietary protein levels. A total of 29-32% dietary protein level would be the appropriate level range to improve muscle quality and promote the antioxidant and autophagy capacity of triploid crucian carp muscles.
本研究旨在探讨日粮蛋白质水平对三倍体鲫鱼肌肉肉质、氧化应激和自噬状态的影响及其相关分子机制。配制了六种不同蛋白质水平（26%、29%、32%、35%、38%、41%）的实验日粮。将540尾初始体重为11.79±0.09 g的鱼随机分配到18个网箱中，分为六个处理组，每组30尾鱼，重复三次，投喂8周。结果发现，高蛋白水平组的鱼体灰分含量显著增加（P<0.05）。日粮蛋白质水平为29%的组肌肉水分含量最高，不过与其他组相比，其肌肉咀嚼性有不明显下降。日粮蛋白质水平影响游离氨基酸和核苷酸含量，尤其是风味氨基酸含量，其随蛋白质水平升高呈上升趋势，如丙氨酸和谷氨酸，而风味核苷酸呈现不同的波动趋势。此外，肌肉发育相关基因受日粮蛋白质水平影响，尤其是MyoD的表达，其随日粮蛋白质水平升高而上调。与其他日粮水平相比，日粮蛋白质水平为29%时，多数分析的肌肉基因表达促进至最高水平，但MyoG除外，其在日粮蛋白质水平为38%时表达最高。此外，还研究了日粮蛋白质水平对抗氧化信号通路基因的影响。高蛋白水平会促进Keap1的表达；Nqo1和Gclc mRNA表达在日粮蛋白质水平为32%的组最高。日粮蛋白质水平升高通过上调Bach1降低Nrf2的mRNA和蛋白表达。自噬相关基因表达水平在日粮蛋白质水平为32%时达到峰值，FoxO1蛋白表达的类似变化证明了这一点。总之，日粮蛋白质水平影响肌肉营养成分、抗氧化途径和自噬水平。日粮蛋白质水平为29% - 32%是改善三倍体鲫鱼肌肉品质、促进其抗氧化和自噬能力的适宜水平范围。
