Mechanistic Study On The Alleviating Effect Of Capsaicin On Subacute Ruminal Acidosis In Beef Cattle

Subacute ruminal acidosis（SARA）is a nutritional metabolic disease that causes changes in feed intake,productivity and the rumen environment in ruminants,damaging the rumen epithelial barrier and thus affecting the morphology and function of the entire digestive tract,indirectly leading to anorexia,liver abscesses and hoof laminitis（Zebeli et al.,2012）.,this metabolic disease is mainly triggered by the high intake of high concentrates in ruminants,which impairs rumen function.Capsaicin,a plant extract with various biological effects such as antibacterial and anti-inflammatory,has been widely used in livestock production and needs to be studied in depth.Therefore,this study was conducted to investigate the mechanism of capsaicin’s alleviating effect on subacute rumen acidosis in beef cattle by adding capsaicin to high concentrate and analysing growth performance,chewing activity,rumen internal environment and blood indices.Study on the effect of capsaicin supplementation on growth performance and chewing activity of beef cattle under SARA conditionsTo explore the effect of capsaicin on the growth performance and chewing activity of beef cattle with subacute rumen acidosis,18 Simmental and Lucian crossbred cattle in good condition and weighing about 400 kg provided by Bai Fu Heng beef farm were selected for the experiment.The experiment was randomly divided into three treatment groups of six cattle each using a randomised block design.Group 1: high roughage group（Con）;Group 2:high concentrate group（SARA）;Group 3: high concentrate plus capsaicin group（SARA +CAP,capsaicin content 250 mg/d/head）,with a 14 d pre-test period and a 90 d formal period during which the cattle were sterilised,numbered and weighed,followed by a 90 d fattening trial.The test cattle were tethered and fed twice daily,once at 6:00am and once at 18:00pm,with leftovers controlled to within 10%（fresh weight）.During the trial,the basic conditions of the cattle,performance indicators and chewing activity were recorded.On the last day of the trial,all were slaughtered,meat samples were collected and slaughter performance was measured.The average daily weight gain and feed conversion ratio of the SARA + CAP group were found to be significantly higher than those of the SARA group（P < 0.05）.The results of feeding time,total chewing time,meat colour,drip loss and texture analysis in the control group were significantly higher than those of the SARA and SARA + CAP groups（P < 0.05）,and the SARA + CAP group was significantly higher than the SARA group（P <0.05）.Shear,monounsaturated fatty acids,polyunsaturated fatty acids and total fatty acids were significantly lower in the control group than in the SARA and SARA + CAP groups（P< 0.05）,and significantly lower in the SARA + CAP group than in the SARA group（P <0.05）.The results indicated that the addition of SARA + CAP to beef cattle diets under SARA conditions could improve the growth performance and meat quality of ruminants.Study on the mechanism of rumen environment regulation in beef cattle under SARA conditions with the addition of capsaicin to the dietAfter slaughter,rumen fluid was taken from beef cattle and passed through the rumen using four layers of gauze prepared in advance.The filtered rumen fluid was divided into two portions,one stored at-20°C in the refrigerator for the determination of rumen fermentation index and the second stored at-80°C in the refrigerator for the determination of the rumen internal environment.The test results showed that the dry matter intake,growth performance and daily weight gain of the SARA group were significantly higher（P < 0.05）than those of the control and SARA + CAP groups,while there was no significant difference（P > 0.05）between the SARA + CAP group and the control group.Compared to the SARA group,the SARA + CAP group had significantly higher p H ratios（P < 0.05）and significantly lower ratios of acetic acid,propionic acid and butyric acid,and total volatile fatty acid content（P < 0.05）.The results indicate that the addition of capsaicin was able to improve the index of rumen fermentation caused by high concentrate diets to a certain extent,preventing the disturbance of the rumen internal environment and thus being able to maintain a stable rumen internal environment.Study on the effect of capsaicin addition to the diet on the immunity and antioxidant function of beef cattle under SARA conditionsBlood was collected from the aseptic jugular vein of the above test beef cattle before slaughter,centrifuged at 3500 rpm/min for 15 min in a centrifuge,serum was divided and stored in six 1.5 ml sterile tubes in a-20°C refrigerator for reserve,and the indicators in the serum were measured for subsequent analysis.The test results showed that complement C3 and glutathione peroxidase（GSH-Px）were lower in the SARA and SARA + CAP groups（P< 0.05）than in the control group,and were significantly higher in the SARA + CAP group than in the SARA group（P < 0.05）.Interleukin-8（IL-8）and malondialdehyde（MDA）in serum were significantly lower in the control group than in the SARA and SARA + CAP groups（P < 0.05）,and significantly lower in the SARA + CAP group than in the SARA group（P < 0.05）.The results indicate that when subacute rumen acidosis occurs in beef cattle,they are in a negative energy balance and their liver function is impaired.In addition,the immunity and antioxidant function of the organism in beef cattle with subacute rumen acidosis is reduced overall,which was significantly alleviated when capsaicin was added to the diet,and the immunity and antioxidant function of beef cattle with capsaicin was improved.High concentrate diets lead to inflammatory factors in the blood and induce an inflammatory response in the organism.The addition of capsaicin reduces the accumulation of these inflammatory substances in the body and reduces the risk of inflammation of the rumen epithelium caused by high concentrate diets and improves the rumen epithelial barrier function through the regulation of cytokine activity.In conclusion,capsaicin has a mitigating effect on subacute rumen acidosis in beef cattle,and its mechanism of action is related to the immuno-antioxidant function of capsaicin,and this study also provides a theoretical basis for the health of ruminants during fattening.