Dietary phytosterols increased the rate of weight gain, antioxidant capacity and growth of beneficial strains of bacteria in the gut and suppressed the population of potentially pathogenic bacteria in largemouth bass (Micropterus salmoides)

This study evaluated the effects of feed supplementation with plant sterols on growth, an-tioxidant capacity and gut microbiota of largemouth bass. The results revealed that (1) the ad-dition of 0.04 % phytosterol (PS) to the diet was found to significantly increase the weight gain rate and fattening rate of largemouth bass. (2) Weight gain and fattening rate of largemouth bass. Liver cells were more compact and vacuolisation was significantly reduced. (3) The width of the posterior intestinal folds and the thickness of the muscles were significantly increased. (4) Highest superoxide dismutase (SOD) and catalase (CAT) activities in serum. (5) The highest relative expression of the growth-promoting hypothalamic growth hormone (gh), pituitary Insulin-like growth factor (igf1ra, igf1rb, and igf2r) genes. (6) The intestinal flora had in-creased abundance of Firmicutes, Cetobacterium and decreased relative abundance of harmful bacteria such as Bacteroidota.

本研究评估了植物甾醇（phytosterol, PS）饲料添加对大口黑鲈生长性能、抗氧化能力及肠道菌群的影响。结果显示：
1. 日粮中添加0.04%植物甾醇可显著提升大口黑鲈的增重率与肥满率；
2. 大口黑鲈肝细胞排列更为紧密，空泡化程度显著降低，且其增重与肥满率得到改善；
3. 后肠褶皱宽度与肌肉层厚度显著增加；
4. 血清中超氧化物歧化酶（superoxide dismutase, SOD）与过氧化氢酶（catalase, CAT）活性达到最高水平；
5. 促生长相关基因的相对表达量达峰值，包括下丘脑生长激素（growth hormone, gh）、垂体胰岛素样生长因子（insulin-like growth factor, igf1ra、igf1rb及igf2r）基因；
6. 肠道菌群中厚壁菌门（Firmicutes）、鲸杆菌属（Cetobacterium）的丰度提升，而拟杆菌门（Bacteroidota）等有害菌的相对丰度降低。