Study On The Effects Of Conjugated Linoleic Acid Supplementation On Growth,Energy Metabolism And Antler Quality Of Sika Deer

This paper studied the effects of different levels of conjugated linoleic acid(CLA)on the production performance,blood biochemical indexes,nutrient digestibility,gas metabolism,antler fatty acid metabolism,respiratory calorimetry,protein and energy utilization and deposition.The appropriate amount of CLA and the maintenance requirements of protein and energy in the diet of sika deer were determined,which provided sufficient theoretical basis for the establisment of nutrition standard and elabrorative breeding of sika deer in China.This paper includes five experiments,the main study contents and results are as follows:Experiment 1:A single factor test was conducted to evaluate the effects of conjugated linoleic acid supplementation on one year old male sika deer.Sixteen deer were divided in four groups(from G0 to G3)of four animals each according to their body weight.Deer in G0 were fed a basal diet without conjugated linoleic acid supplementation.Deer in G1,G2 and G3 were fed diets supplemented with conjugated linoleic acid and the concentrations were 0.25%,0.5%and 1.0%.Growth performance,nutrient digestibility and blood biochemical indexes were measured.The results indicated that the supplementation of CLA significantly increased ADG,ADFI and feed utilization of sika deer(P<0.05).The activity of alkaline phosphatase(ALP)in serum increased significantly(P<0.05)because of CLA supplementation.CLA supplementation to diet played a positive role for the growth of sika deer.Experiment 2:It was conducted to study the changes of rumen fermentation parameters and the effects on antler production performance by adding different levels of CLA in sika deer diet,so as to provide basis for the application of CLA in sika deer production in the later stage.In the middle of experiment 1,rumen fluid samples were collected to determine p H value,ammonia nitrogen and volatile fatty acids and the production performance indexes of antler were recorded at maturity.The results showed that the p H value of rumen fluid decreased significantly after adding CLA to the diet of1-year-old sika deer(P<0.05);The content of ammonia nitrogen increased with the increase of CLA supplementation levels,and there was significant difference among 0.5%group and 1.0%group and the control group(P<0.05);The levels of dietary CLA supplementation had a significant effect on the content of total volatile fatty acids,acetic acid and isobutyric acid(P<0.05),and showed a downward trend.When the level of CLA was 0.5%,the content of propionic acid was slightly higher than that of other groups,and the ratio of ethylene to propylene in this group was significantly lower than that of the control group,indicating that when the level of CLA was 0.5%,the rumen fermentation mode of deer was mainly propionic acid fermentation,The rumen fermentation mode of deer was changed,the rumen energy supply efficiency was improved,and the growth and development of deer were promoted;When0.5%CLA was added to the diet,the fresh weight of antler was significantly higher than that of the control group(P<0.05).The average daily gain of fresh antler with 0.5%CLA reached a significant level compared with other groups(P<0.05),indicating that CLA had a positive regulatory effect on the growth of antler and the yield of antler increased.Experiment 3:It was conducted to explore the effect of fatty acid metabolites in sika deer antler with different levels of CLA supplementation.The results will provide scientific theoretical support for the fine feeding and precise preparation of feed in sika deer.The antler used from experiment 2 and the fatty acid metabolism in deer antler was studied through targeted metabolome technology.T he results showed that 35 kinds of fatty acids were detected after adding CLA,which was more than that of other scholars;CLA supplementation could increase the content of most fatty acids in antler,among which the contents of palmitoleic acid,stearic acid,oleic acid,trans oleic acid,linoleic acid,trans linoleic acid,eicosadienoic acid and arachidonic acid increased significantly(P<0.05).The proportion of PUFA and SFA in antler for 0.5%CLA was significantly higher than that in control group(P<0.05),and the proportion of MUFA in this group was significantly lower than that in control group(P<0.05).The deposition of PUFA in deer antler has a positive effect to the quality of deer antler.The effect was most pronounced when the CLA was added at 0.5%.Experiment 4:The purpose was to study the effects of CLA on the enzyme activity related to intramuscular fat deposition and the gene expression related to intramuscular fat deposition in antler,and to reveal the mechanism of CLA on the improvement of antler quality from the enzyme activity and molecular level.The results showed that the supplementation of CLA to the diet of 1-year-old sika deer could regulate fatty acid metabolism and significantly improve the activities of fatty acid synthase FAS and ACC in antler(P<0.05).The expression of the fatty acid synthesis related gene SREBP-1,PPAR-?,FAS,ACC was up regulated(P<0.05);The supplementation of CLA in diet decreased the activities of key lipolytic enzymes HSL and CPT-1(P<0.05)significantly and the m RNA expression of key lipolytic genes HSL and CPT-1 was inversely regulated(P<0.05).It promoted intramuscular fat deposition,increased its tenderness and improved the quality of deer antler when the supplementation of CLA was0.5%.Experiment 5:The objective of this study is to study the effects of dietary intake levels on energy metabolism,carbon(C),and nitrogen(N)balance and to determine the maintenance requirements of energy and protein for male sika deer during their growing period.A total of 16 one-year-old male sika deer with similar body weight(BW)(63.25±2.42 kg)were selected,with four animals per feed intake level.The feeding levels of the four groups for deer were 100%,80%,60%and 40%of the recommended amount,respectively.The nutrient digestibility and methane production were measured through digestion trials and respiratory trials.A 4×4 Latin Square design was performed in a respirometry trial.The result shown that,the MEm and NEm values of growing male sika deer were estimated to be 223.62 and 251.17 k J·kg^-1BW^0.75·d^-1,respectively according to the logarithmic regression between the HP and MEI The NNm and NPm values of growing male sika deer were estimated to be251.8 mg·kg^-1BW^0.75·d^-1 and 1.57 g·kg^-1BW^0.75·d^-1,respectively based on the linear regression relationship between daily NI and RN.In summary,when the level of CLA in the diet was 0.5%,it can improve the ADG,ADFI and feed utilization of sika deer significantly;the rumen was mainly propionic acid fermentation,which can effectively improve the body metabolism and feed conversion rate;the proportion of PUFA and SFA in antler also increased significantly,which promoted the intramuscular fat deposition in antler and promoted the quality of antler.The values of maintenance metabolic energy(MEm)and maintenance net energy(NEm)of male sika deer in growing period were estimated to be 223.62 and 251.17k J·kg^-1BW^0.75·d^-1,respectively.The net nitrogen(NNm)and net protein(NPm)required for the maintenance of male sika deer during the growing period were estimated to be 251.8 mg·kg^-1 BW^0.75·d^-1and 1.57 g·kg^-1BW^0.75·d^-1.