This study investigated the effects of different dissolved oxygen (DO) levels on the growth performance, antioxidant response and apoptosis of juvenile GIFT (genetically improved farmed tilapia, Oreochromis niloticus). GIFT were fed with five DO levels (1, 2, 3, 4 and 5 mg/L) for 60 days, and the results showed that the final body weight, weight gain rate, specific growth rate and crude protein and crude lipid contents of the fish muscle increased at 5 mg/L DO. The activities of the antioxidant and digestive enzymes were significantly up‐regulated with increasing DO levels. However, the haemoglobin content, number of red blood cells, malondialdehyde content, transaminase activities, glucose content and lactic acid levels decreased at higher DO levels. Furthermore, the cardiomyocyte apoptotic index was significantly decreased with increasing DO levels. Our results show that 5 mg/L DO improved growth performance, promoted antioxidant enzyme activities and reduced liver damage in GIFT.

中文翻译：

---

溶解氧对幼年GIFT（尼罗罗非鱼）生长性能，血液学参数，抗氧化反应和细胞凋亡的影响

这项研究调查了不同溶解氧（DO）水平对少年GIFT（遗传改良的养殖罗非鱼，尼罗罗非鱼）的生长性能，抗氧化反应和细胞凋亡的影响）。GIFT分别饲喂五种DO（1、2、3、4和5 mg / L）60天，结果显示最终体重​​，体重增加率，比生长率以及粗蛋白和粗脂含量鱼肌肉以5 mg / L DO的速度增加。随着溶解氧水平的升高，抗氧化剂和消化酶的活性明显上调。然而，在较高的DO水平下，血红蛋白含量，红细胞数量，丙二醛含量，转氨酶活性，葡萄糖含量和乳酸水平降低。此外，随着DO水平的升高，心肌细胞凋亡指数显着降低。我们的结果表明，在GIFT中，5 mg / L的DO改善了生长性能，促进了抗氧化酶的活性并减少了肝损伤。