Study On The Alleviating Effect Of Rumen-protected Creatine Pyruvate On Transport Stress Of Beef Cattle

With the development of the livestock breeding industry,long-distance transport is an inevitable phase for the cattle industry,including off-sit fatting,slaughter,and processing.The fasting and stress associated with long-distance transportation contributes to a lack of energy and a decline in the immune system of beef cattle,thereby,high mortality rates frequently occur following long-distance transportation and leads to enormous economic losses.Creatine pyruvate（CrPyr）is a new multifunctional nutrient that contains pyruvate and creatine,both are related products of energy metabolism.This study uses a combination of in vitro and in vivo experiments to explore the effects of CrPyr on rumen fermentation function and the mechanism of alleviating transport stress in beef cattle to provide a theoretical basis for the development and utilization of CrPyr to alleviate transport stress in beef cattle.The details are as follows:Experiment 1:This experiment was conducted to explore the effects of dietary supplemented with CrPyr on the fermentation characteristics of Jinjiang cattle in vitro.A single factor randomized design was adopted for the experiment.Diets were supplemented with 0,0.4%,0.8%,1.2%,1.6%,3.2%dry matter CrPyr and incubated in vitro for 0,12,and24 h,respectively.The pyruvate and creatine concentrations,and fermentation parameters were measured.The results showed that:1)At the 24th hour of fermentation,the p H of the1.6%group was significantly higher than that of the control group（P<0.01）.2)The contents of NH₃-N at the 12th and 24th hour of fermentation was significantly and extremely significantly higher in the 3.2%group compared with the control group（P<0.05 and P<0.01）.3)At 0 hour of fermentation,the contents of pyruvate in the 1.2%,1.6%and 3.2%groups were significantly higher than that in the control group（P<0.01）,and the degradation rate of pyruvic acid increases with the increase of the addition amount.4)The contents of creatine at 0,12th hour and 24th hour of fermentation was extremely significantly higher in 1.2%,1.6%and 3.2%groups compared with the control group（P<0.05）,and the degradation rate of creatine reduced with the increase of the addition amount.These results showed that CrPyr could be degraded in the rumen.5)At the 24th hour of fermentation,the contents of acetic acid,iso valeric acid and TVFA in the 1.6%addition group were extremely significantly higher than the control group（P<0.05）,the level of iso-butyric was significantly higher than the remaining groups（P<0.05）.Experiment 2:Previous studies have shown that CrPyr is easily degraded in the rumen,so we added rumen-protect CrPyr（RP-CrPyr）to the diet to explore its relieving effect on transport stress in beef cattle.To investigate the effects of transport and rumen-protected（RP）-CrPyr on the blood biochemical parameters,rumen fluid characteristics of beef cattle and structure and function of the jejunum,twenty male Simmental crossbred cattle（659±16 kg）aged 18 months were randomly allocated to four groups（n=5）using a 2×2 factorial arrangement with two RP-CrPyr supplemental levels（0 or 140g/d）and two transport treatments（5min or 12h）:T＿CrPyr140,T＿CrPyr0,NT＿CrPyr140,and NT＿CrPyr0.After feeding for 30days,three cattle per treatment were slaughtered.Compared with none transport group,transport decreased the total antioxidant capacity,catalase activity,contents of Ig A,interferonγ,interleukin-1β（IL-1β）,and IL-6 in serum,and the amounts of total volatile fatty acids（TVFA）,acetate,and butyrate in rumen（P<0.05）;increased the serum lipopolysaccharide（LPS）level,contents of rumen LPS and ammonia nitrogen（P<0.05）.RP-CrPyr supplementation decreased the levels of cortisol and LPS in serum and the butyrate concentration in the rumen of beef cattle compared with those in the none-supplementation groups（P<0.05）RP-CrPyr and transport interaction had a significant effect on the contents of serum tumour necrosis factor-α,IL-6,LPS,ruminal p H,acetate content,and acetate/propionate（P<0.05）.In terms of ruminal bacterial composition,group T＿CrPyr0 increased the Prevotella genus abundance compared with group NT＿CrPyr0（P<0.05）,while group T＿CrPyr140 increased Firmicutes phylum abundance and decreased Bacteroidetes phylum and genus Prevotella abundance compared with group T＿CrPyr0（P<0.05）.Moreover,Bacteroidetes was positively correlated with serum LPS.In terms of the structure and function of jejunum,long-distance transportation will break and damage the jejunum villi,resulting in a significant decrease in the ability of T-AOC in jejunum（P<0.05）,and has no significant effect on the expression of jejunal mucositis factor m RNA.In conclusion,CrPyr can be degraded in the rumen and promote the rumen fermentation function,and transport stress elicited negative changes in endocrine parameters,antioxidant status,immunity,rumen fermentation and microorganisms of beef cattle.Dietary supplementation with RP-CrPyr might be beneficial to alleviate transport stress by decreasing serum cortisol and LPS levels and promoting the restoration of the rumen natural fora.