Background

Seriola lalandi is an important species for aquaculture, due to its rapid growth, adaptation to captivity and formulated diets, and high commercial value. Due to the rise in fishmeal (FM) price, efforts have been and still are made to replace it partially or entirely with vegetable meals in diets for carnivorous fish. The use of prebiotics when feeding vegetable meals has improved fish health.

Methods

Four experimental diets were assessed in juveniles, the control diet consisted of FM as the main protein source, the second diet included 2% of GroBiotic®-A (FM-P), in the third diet FM was partially replaced (25%) by soybean meal (SM25), and the fourth consisted of SM25 with 2% of GroBiotic®-A (SM25-P). Growth was evaluated and RNA-seq of the liver tissue was performed, including differential expression analysis and functional annotation to identify genes affected by the diets.

Results

Growth was not affected by this level of FM replacement, but it was improved by prebiotics. Annotation was achieved for 59,027 transcripts. Gene expression was affected by the factors: 225 transcripts due to FM replacement, 242 due to prebiotics inclusion, and 62 due to the interaction of factors. The SM25-P diet showed the least amount of differentially expressed genes against the control diet.

Conclusion

The replacement of FM (25%) by soybean meal combined with prebiotics (2%) represents a good cost-benefit balance for S. lalandi juveniles since the fish growth increased and important metabolic and immune system genes in the liver were upregulated with this diet.

中文翻译：

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太平洋黄尾鱼（Seriola lalandi）幼鱼肝脏中膳食鱼粉部分替代豆粕和益生元的转录组学评估

 背景

鰤鱼因其生长快、适应圈养和配制饲料以及较高的商业价值而成为水产养殖的重要品种。由于鱼粉（FM）价格上涨，人们已经并且仍在努力在肉食性鱼类的饲料中部分或全部用蔬菜粉替代。饲喂蔬菜膳食时使用益生元可以改善鱼类的健康。

 方法

在青少年中评估了四种实验饮食，对照饮食以 FM 作为主要蛋白质来源，第二种饮食包含 2% 的 GroBiotic®-A (FM-P)，第三种饮食中 FM 被部分替代 (25%)豆粕 (SM25)，第四种由 SM25 和 2% GroBiotic®-A (SM25-P) 组成。评估了肝组织的生长情况并进行了 RNA 测序，包括差异表达分析和功能注释，以识别受饮食影响的基因。

 结果

生长并未受到这种水平的 FM 替代的影响，但益生元可以改善生长。已完成 59,027 份转录本的注释。基因表达受到以下因素的影响：225 个转录本由于 FM 替换，242 个转录本由于益生元的包含，62 个转录本由于因素的相互作用。 SM25-P 饮食与对照饮食相比，显示差异表达基因的数量最少。

 结论

用豆粕和益生元 (2%) 替代 FM (25%) 对于拉兰迪鮈幼鱼来说具有良好的成本效益平衡，因为这种饮食可以促进鱼类生长，并且肝脏中重要的代谢和免疫系统基因上调。