Effects Of Soybean Oil And Copper On Performance,Ruminal Fermentation And Lipid Metabolism In Holstein Dairy Bulls

The study investigated the effects of copper sulphate(CS)and soybean oil(SO)on growth performance,nutrition digestion and lipid metabolism in dairy cows.Sixteen Holstein cows with 328 ± 7.0kg of body weight were randomly assigned(2 × 2 factorial arrangement)into 4 groups: control group(basal diets);CS+(basal diets + 8 mg Cu per kg dietary dry matter [DM] as CS);SO+(basal diets + 4% SO);CS+ SO+(basal diets 8 mg Cu as CS/kg DM as CS and 4% SO).Addition of CS increased(P<0.05)dry matter intake(DMI),average daily gain(ADG),digestibility of crude protein(CP)and neutral detergent fibre(NDF),but reduced(P<0.05)feed conversion ratio(FCR).Addition of CS increased(P<0.05)total volatile fatty acids(TVFA)concentration but reduced(P<0.05)acetate to propionate ratio.Addition of CS increased(P<0.05)activities of carboxymethyl-cellulase,xylanase and protease as well as the populations of total bacteria,fungi and protozoa.Addition of CS increased(P<0.05)blood concentration of growth hormone(GH)and ceruloplasmin.Addition of CS increased(P<0.05)polyunsaturated fatty acids of longissimus dorsi fat(PUFA).Addition of CS reduced(P<0.05)expression of peroxisome proliferator activated receptor alpha of intramuscular(PPARα).Addition of SO increased(P<0.05)digestibility of organic matter(OM)and ether extract(EE).Addition of SO increased(P<0.05)propionate molar proportion,but reduced(P<0.05)acetate to propionate ratio and ammonia nitrogen concentration.Activity of xylanase increased(P<0.05)with addition of SO.But activities of carboxymethyl-cellulase,cellobiase and xylanase reduced(P<0.05)with addition of SO.Populations of P.ruminicola and R.amylophilus increased(P<0.05)with addition of SO,but populations of R.albus and R.flavefaciens reduced(P<0.05).Addition of SO increased(P<0.05)blood concentrations of growth hormone(GH)and insulin-like growth factor-1(IGF-1).Addition of SO increased(P<0.05)monounsaturated fatty acids fatty acids(MUFA)of longissimus dorsi fat,but reduced(P<0.05)PUFA.Addition of SO reduced(P<0.05)expression of PPARα,sterol regulatory element-binding transcription factor 1(SREBP)and acetyl-Co A carboxylase 1(ACC)of intramuscular.Lower(P<0.05)acetate to propionate ratio,SFA in longissimus dorsi fat,the expression of SREBP and CPT1,and higher MUFA in longissimus dorsi fat were observed for the combined addition of SO and CS compared with single addition of CS.In summary,dietary supplementation with CS and SO both improved growth performance.Dietary supplementation with CS improved rumen fermentation.The combination of CS and SO improved fatty acid ratio in longissimus dorsi fat.