Pyruvate and creatine, energetics and antioxidant substances, can promote rumen fermentation and metabolism. This study aimed to evaluate the stress resistance and rumen fermentation effects of the compound creatine pyruvate (CrPyr) in diets for beef cattle under heat stress. Four Jinjiang steers fitted with permanent rumen cannulas were used in a 4 Ã— 4 Latin square design and fed a diet supplemented with CrPyr at 0, 20, 40, or 60 g/d. Heat stress was employed for 62 of 64 days. Supplementing with CrPyr elevated their levels of free triiodothyronine and triiodothyronine, superoxide dismutase activity, ruminal pH value, microbial crude protein concentration, crude fat digestibility, nitrogen intake, and levels of urine allantoin and total purine derivatives. It also reduced their levels of cortisol and corticosterone, malondialdehyde concentration, lactate dehydrogenase activity, and urine nitrogen excretion. In conclusion, CrPyr relieves the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis.

中文翻译：

---

通过膳食补充丙酮酸肌酸改善热应激下肉牛的抗氧化活性和瘤胃发酵

丙酮酸和肌酸是能量和抗氧化物质，能促进瘤胃发酵和新陈代谢。本研究旨在评估复合丙酮酸肌酸 (CrPyr) 在热应激下肉牛日粮的抗逆性和瘤胃发酵效果。在 4 × 4 拉丁方设计中使用了四头装有永久瘤胃插管的晋江阉牛，并在 0、20、40 或 60 g/d 的情况下喂食补充 CrPyr 的饮食。64 天中有 62 天采用热应激。补充 CrPyr 可提高其游离三碘甲状腺原氨酸和三碘甲状腺原氨酸的水平、超氧化物歧化酶活性、瘤胃 pH 值、微生物粗蛋白浓度、粗脂肪消化率、氮摄入量以及尿尿囊素和总嘌呤衍生物的水平。它还降低了他们的皮质醇和皮质酮水平，丙二醛浓度，乳酸脱氢酶活性和尿氮排泄。总之，CrPyr 通过提高抗氧化活性和瘤胃微生物蛋白合成来缓解肉牛的热应激。