The aim of this study was to investigate the effects of different concentrations of glutamine (experiment 1) and glutamine + cysteine (experiment 2) on post‐thaw sperm quality of South American silver catfish (Rhamdia quelen). The sperm was cryopreserved in cryoprotectant solution (fructose 50 g/L, powdered milk 50 g/L and methanol 100 ml/L) containing different glutamine concentrations (0, 2.5 and 5 mM; experiment 1) and a combination of glutamine (2.5 and 5 mM) and cysteine (2.5 and 5 mM; experiment 2). In experiment 1: glutamine supplementation groups increased DNA fragmentation; the concentration of carbonyl groups was lower and the concentration of sulfhydryl groups was higher in control; a higher activity of superoxide dismutase (SOD), catalase (CAT), glutathione‐S‐transferase (GST) and glutathione peroxidase (GPx) enzymes was observed in the 2.5 and 5 mM groups. In experiment 2: the group with 5 mM of cysteine +5 mM of glutamine presented the higher DNA damage; treatments with 5 mM of glutamine presented the higher concentration of carbonyl groups and a higher activity of CAT and GST. The findings of this study show that glutamine and cysteine, at the concentrations evaluated in this study, does not present satisfactory results but rather damaging effects on sperm quality of R. quelen.

中文翻译：

---

谷氨酰胺和半胱氨酸补充对南美银silver鱼冷冻保存精子质量的影响

这项研究的目的是研究不同浓度的谷氨酰胺（实验1）和谷氨酰胺+半胱氨酸（实验2）对南美白cat（Rhamdia quelen）解冻后精子质量的影响。。将精子冷冻保存在含有不同谷氨酰胺浓度（0、2.5和5 mM；实验1）和谷氨酰胺（2.5和2.5 mg / ml）的防冻剂溶液（果糖50 g / L，奶粉50 g / L和甲醇100 ml / L）中。 5 mM）和半胱氨酸（2.5和5 mM；实验2）。在实验1中：补充谷氨酰胺的组增加了DNA片段化；对照中羰基浓度较低，巯基浓度较高。在2.5和5 mM组中观察到较高的超氧化物歧化酶（SOD），过氧化氢酶（CAT），谷胱甘肽S-转移酶（GST）和谷胱甘肽过氧化物酶（GPx）酶的活性。在实验2中：半胱氨酸5 mM +谷氨酰胺5 mM的组表现出较高的DNA损伤。用5 mM的谷氨酰胺进行的处理显示出较高的羰基浓度以及较高的CAT和GST活性。这项研究的结果表明，在该研究评估的浓度下，谷氨酰胺和半胱氨酸不能提供令人满意的结果，而是对精子质量的破坏作用。[R 。奎伦。