| The objective of this study was to determine the effects of coated pantothenate(CPA)and coated folic acid(CFA)on growth performance,nutrient digestion,rumen fermentation,blood hormone level and gene expression related to protein metabolism in Holstein dairy calves.Sixteen Chinese Holstein dairy calves with 60 days of age and 123 ± 2.5 kg of body weight were assigned to one of four groups in a randomized experimental design with a 2 × 2 factorial arrangement:(1)control group;(2)CPA(50 mg PA as CPA per kg diet dry matter [DM]);(3)CFA(8.5 mg FA as CFA per kg diet DM).(4)CPA + CFA(same with CPA group and CFA group).Addition of CPA or CFA increased(P<0.05)dry matter intake(DMI)and average daily gain(ADG)but reduced(P<0.05)feed conversion ratio(FCR).Dietary CPA or CFA supplementaion increased(P<0.05)digestibility of DM,organic matter(OM),crude protein(CP)and neutral detergent fibre(NDF)and nitrogen retained.Supplementation of CPA or CFA increased(P<0.05)total volatile fattys(TVFA)concentration and urinary excretion of total purine derivatives but reduced(P<0.05)ruminal p H and ammonia nitrogen concentration.Acetate to propionate ratio increased(P<0.05)with CFA addition but reduced(P<0.05)with CPA addition.Activity of xylanase and pectinase increased(P<0.05)with addition of CPA or CFA.Activity of carboxymethyl-cellulase,α-amylase and protease increased(P<0.05)with addition of CFA.Addition of CPA or CFA increased(P<0.05)population of R.albus,R.flavefaciens,F.succinogenes and Rb.amylophilus.Dietary CFA addition increased(P<0.05)population of total bacteria,total anaerobic fungi,total protozoa,total methanogens,B.flavefaciens and P.ruminicola.Supplementation of CPA increased(P<0.05)blood concentration of glucose(Glu),insulin(INS),PA,acetyl coenzyme A,growth hormone(GH)and insulin-like growth factor-1(IGF-1)but reduced(P<0.05)blood concentration of total cholesterol(TC).Supplemented with CFA increased(P<0.05)blood concentration of Glu,INS,albumin,TC and FA but decreased(P<0.05)concentration of homocysteine.Addition of CPA or CFA increased(P<0.05)expression of ribosomal protein S6 kinase(P70S6K)in muscle.Supplement of CFA increased(P<0.05)expression of IGF-1,phosphoinositide 3-kinase,mammalian target of rapamycin(m TOR)and P70S6 K in liver and m TOR and P70S6 K in muscle.The significant(P<0.05)CPA and CFA interaction was observed for serum total protein concentration.The data indicated that dietary CPA or CFA supplementation improved growth performance,nutrient digestibility,rumen TVFA concentration and protein metabolism gene expression of dairy calves. |
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