Effects Of Yeast Selenium Level On Nutrient Digestion,Absorption And Selenium Protein Expression In Velvet Antler Of Sika Deer During Growing Stage

In this study,feeding test,digestion test,serum biochemical indexes,rumen and intestinal microorganism changes,etc.were used to explore the appropriate selenium supplemental level in the diet of sika deer in velvet antler growing stage.So as to provide scientific theoretical reference for precise feeding of sika deer in velvet antler stage.Twenty five-year-old healthy male sika deer with similar body condition were randomly divided into 4 groups with 5 replicates per group and each group was fed in a single house.Sika deer in each group were fed the basal diet supplemented with 0 mg/kg(group Ⅰ,control group),0.3 mg/kg(group Ⅱ),1.2 mg/kg(group Ⅲ)and 4.8 mg/kg(group Ⅳ)selenium,respectively.The pretest lasted for 7 days,and the experimental period lasted for 110 days.The effects of different selenium levels on performance,nutrient digestibility,serum biochemical indexes,selenoprotein gene and protein expression levels,and abundance of bacteria in rumen and intestinal fluid of sika deer were evaluated to explore the appropriate dietary selenium level.The results showed that: 1)The apparent digestibility of crude protein in the group Ⅱ was extremely significantly higher than group Ⅲ(P<0.01).The apparent digestibility of dry matter,calcium,and phosphorus in the group Ⅱ was extremely significantly higher than that in the group Ⅰ and group Ⅲ(P<0.01).The apparent digestibility of dry matter,crude protein,and phosphorus in the group Ⅱ were significantly higher than that in the group Ⅳ(P<0.05).The apparent digestibility of selenium in the group Ⅱ was extremely significantly higher than that in the group Ⅲ andⅣ(P<0.01).2)The digestibility of neutral detergent fiber(NDF)and acid detergent fiber(ADF)in the group Ⅱ was significantly higher than that in the group Ⅰ,group Ⅲ,and group Ⅳ(P<0.01).The digestibility of cellulose of sika deer in the group Ⅱ was significantly higher than that in the group Ⅰ,groupⅢ,and group Ⅳ(P<0.01).And the digestibility of crude fiber of sika deer in the group Ⅱ was significantly higher than that in the group Ⅲ and group Ⅳ(P<0.01),and significantly higher than that in the group Ⅰ(P<0.05).3)The serum alkaline phosphatase activity of sika deer in the group Ⅱ and group Ⅲ was extremely significantly higher than that in group Ⅰ and group Ⅳ(P<0.01).4)The contents of acetic acid and propionic acid in the rumen fluid of sika deer in the group Ⅱ were significantly higher than that in the group Ⅰ(P<0.05).The butyric acid content in the rumen fluid of sika deer in the group Ⅱ was significantly higher than that in the group Ⅳ(P<0.05).5)Group Ⅱ of sika deer rumen of F.succinogenes abundance is significantly higher than the control group(P<0.05),significantly higher than that of group Ⅲ and Ⅳ(P<0.01).Group Ⅱ of sika deer rumen Fibrobacterota abundance group was extremely significantly higher than that of group Ⅰ,group Ⅲ,and group Ⅳ(P<0.01).The abundance of R.albus and F.succinogenes in gut of sika deer in group Ⅱ is significantly higher than that of group Ⅰ(P<0.01).Group Ⅱof sika deer of gut B.fibrisolvens abundance is significantly higher than group Ⅰ(P<0.05).6)The serum thioredoxin oxidoreductase of sika deer in the group Ⅱ was significantly higher than that in the control group(P<0.05).7)The relative expression level of selenoprotein P gene in the velvet mesenchymal layer of sika deer in the group Ⅲ was significantly higher than that in the group Ⅰ and group Ⅱ(P<0.05).The relative expression level of the selenoprotein P gene in the velvet antler anterior cartilage layer of sika deer in the group Ⅲ was significantly higher than that in the group Ⅰ(P<0.05).The relative expression level of the selenoprotein P gene in the velvet cartilage layer of sika deer in the group Ⅱ was significantly higher than that in the group Ⅰ and Ⅳ(P<0.05),and significantly higher than that in group Ⅲ(P<0.01).8)The expression of GPX4 protein in the mesenchymal layer and anterior cartilage layer of velvet antler of sika deer in the group Ⅱ was significantly higher than that in the group Ⅲ and Ⅳ(P<0.01).And the expression of GPX4 in the transition zone layer in the group Ⅱ was significantly higher than that in the group Ⅳ(P<0.01).The protein expression level of GPX4 in the mesenchymal layer,anterior cartilage layer,and transition zone layer of velvet of sika deer in the group Ⅲ was significantly higher than that in the group Ⅳ(P<0.01).The selenoprotein p expression level in the velvet cartilage layer of sika deer in the group Ⅱ was extremely significantly higher than that in the group Ⅳ(P<0.01).The expression level of selenoprotein P in the mesenchymal layer,anterior cartilage layer,transition zone layer,and cartilage layer of sika deer in the group Ⅲ was significantly higher than that in group Ⅰ,group Ⅱ,and groupⅣ(P<0.01).In conclusion,0.3 mg/kg selenium supplementation diet can improve nutrient digestibility,the abundance of gastrointestinal fibrous degrading bacteria and the expression of selenoprotein in sika deer at the velvet antler growing stage.