This study aimed to evaluate the effect of creatine and cysteamine supplementation on the growth performance, fillet quality and resistance to bacterial infection of Streptococcus agalactiae in red tilapia. Five types of experimental diet (quadruplicate) with the same energy and protein content were tested. These consist of N (negative control), A (0.5 g/kg cysteamine), B (0.4 g/kg creatine), C (0.5 g/kg cysteamine plus 0.4 g/kg creatine) and D (0.25 g/kg cysteamine plus 0.2 g/kg creatine). Male red tilapia (Oreochromis sp.), with average body weight of 49.51 ± 4.90 g, were kept in 175-L tank at 10 fish/tank density for 56 days rearing period. The challenge test was carried out through injecting fish (body weight: 152.05 ± 12.2 g) with S. agalactiae 107 CFU/ml as much as 0.10 ml/fish. The results showed that treatment C (0.5 g/kg cysteamine plus 0.4 g/kg creatine) increased (p < 0.05) levels of protein retention, activity of superoxide dismutase (SOD) of the liver (p < 0.05), but decreased levels of malondialdehyde (MDA) and liver glycogen (p < 0.05). This last condition was followed by a decrease (p < 0.05) in plasma protein levels that resulted in a decline (p < 0.05) of water content and MDA of fillet after stored for 24 h. In addition, treatment C increased fish resistance to S. agalactiae infection, demonstrated by higher survival rate and lysozyme activity (p < 0.05). In conclusion, the treatment C boosts protein retention, fillet quality and robustness to pathogenic bacterial infections.

中文翻译：

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饲喂含有半胱胺和肌酸的红罗非鱼（oreochromis sp.）的无乳链球菌攻击后的生长性能、鱼片质量和免疫力

本研究旨在评估补充肌酸和半胱胺对红罗非鱼无乳链球菌的生长性能、鱼片质量和抵抗细菌感染的影响。测试了具有相同能量和蛋白质含量的五种类型的实验饮食（一式四份）。这些包括 N（阴性对照）、A（0.5 g/kg 半胱胺）、B（0.4 g/kg 肌酸）、C（0.5 g/kg 半胱胺加 0.4 g/kg 肌酸）和 D（0.25 g/kg 半胱胺加0.2 g/kg 肌酸）。雄性红罗非鱼 ( Oreochromis sp.) 的平均体重为 49.51 ± 4.90 克，在 175 升水箱中以 10 条鱼/水箱的密度饲养 56 天。通过向鱼（体重：152.05 ± 12.2 g）注射S进行攻击试验。agalactiae 107 CFU/ml 多达 0.10 ml/鱼。结果表明，处理 C（0.5 g/kg 半胱胺加 0.4 g/kg 肌酸）增加了（p < 0.05）肝脏的蛋白质保留水平和超氧化物歧化酶（SOD）的活性（p < 0.05），但降低了丙二醛 (MDA) 和肝糖原 ( p < 0.05)。这最后一个条件是，随后的降低（p在血浆蛋白水平，导致的下降（P <0.05）p的圆角的水含量和MDA <0.05）保存24小时后。此外，处理 C 增加了鱼对S 的抵抗力。无乳杆菌感染，证明了更高的存活率和溶菌酶活性（p< 0.05)。总之，处理 C 提高了蛋白质保留、鱼片质量和对病原性细菌感染的稳健性。