Effects Of Different Doses Of CLA Calcium Salt On Performance,Nutrient Digestibility And Rumen Environment Of Sheep

A study was conducted on the effects of different doses of calcium salts of conjugated linoleic acid(Calcium salts of conjugated linoleic acid;Ca-CLA)on the production performance,nutrient digestibility and rumen environment in sheep diets.18 healthy Small-tailed Han sheep with 2.5 months old,similar body weight(16.49±1.2)kg,genetic background were selected as experimental animals.A random grouping design was adopted to divide the experimental sheep into 3 groups,each group 6.The diet design of each group was as follows:the control group fed the basic diet;the 1.5%CLA group added 1.5%to the basic diet CLA;3.5%CLA the group added 3.5%CLA.The pre-feeding period was 20 days,and the formal feeding period was 60 days.The thesis was divided into three parts:Experiment 1:Effects of different doses of Ca-CLA in the diet on sheep performance.The results showed that the addition of different doses of Ca-CLA in the diet had no significant effect on the stage weight gain,stage daily gain and average feed intake of the test sheep(P>0.05),but the feed weight ratio decreased significantly(P<0.05).The weight of three groups of sheep increased with the increase of date,which was consistent with the performance of fattening sheep.With the addition of Ca-CLA level,the average feed intake value would decrease,which Ca-CLA may affect the palatability of the diet,but the feed weight ratio would decrease significantly,and the feed return rate would be increased.Experiment 2:Effects of different doses of Ca-CLA in the diet on nutrient digestibility.Dietary nutrient digestibility was determined by acid insoluble ash method(AIA).The results showed that the added Ca-CLA had no significant effect on DM,Ca and P digestibility(P>0.05),and had a very significant effect on CP,NDF,ADF,Ash,EE digestibility(P<0.01).Compared with the control group,the CP,NDF and ADF digestibility were significantly increased(P<0.01)in the 3.5%CLA group,while the Ash and EE digestibility were significantly decreased(P<0.01)in the 1.5%group,and NDF digestibility was significantly increased(P<0.01).CP,NDF and ADF digestibility of 3.5%CLA group were significantly higher than 1.5%CLA group(P<0.01),while Ash was significantly lower(P<0.05).The results suggested that supplementation of Ca-CLA in diet had affected the digestibility of nutrients in sheep.Experiment 3:Effects of different doses of Ca-CLA in the diet on rumen environment.(1)The rumen pH was measured by pH meter,the concentration of ammonia nitrogen was determined by colorimetric method,and the content of bacteria cell protein(BCP)in rumen was determined by Coomassie brilliant blue method.The results showed that the rumen pH value was significantly decreased(P<0.01)by adding different doses of CLA compared with the control group,but there was no significant difference between 1.5%group and 3.5%group.The addition of different doses of Ca-CLA had no significant effect on ammonia nitrogen and BCP(P>0.05)compared with the control group,the content of ammonia nitrogen in rumen increased with the increase of Ca-CLA addition,while the content of BCP increased firstly and then decreased.(2)Effects of different doses of Ca-CLA on volatile fatty acids(VFAs)in rumen.the results showed that the addition of different doses of Ca-CLA significantly increased concentration of propionic acid and butyric acid(P<0.05),and had no significant effect on concentration of isovalic acid,valproic acid,acetic acid/propionic acid(P>0.05),acetic acid,TVFA tend to increase significantly(0.05<P<0.1).Overall,with the exception of acetic acid,the concentrations of various VFAs in the 1.5%CLA group were higher than those in the control group and 3.5%CLA group.To sum up,under the conditions of this experiment,adding different doses of Ca-CLA to the diet had no effect on the production performance,but it reduced the feed weight ratio of sheep,increased feed reward,increased the digestibility of CP and fibrous substances,increased the concentration of propionic acid,butyric acid and TVFA,improved rumen VFA fermentation to some extent,promoted propionic acid production,reduced energy loss,and regulated the transformation of rumen metabolism to more energy efficient propionic acid.