Effects Of Coated Folic Acid And Coated Sodium Selenite On Performance,Ruminal Fermentation And Expression Of Genes Related To Protein Metabolism In Holstein Bulls

The study investigated the effects of coated folic acid(CFA)and coated sodium selenite(CSS)supplementation on growth performance,nutrition digestion,ruminal fermentation,blood parameters and m RNA expression of genes related to protein synthesis in dairy bulls.Sixteen Holstein bulls(14 months of age and 508.4 ± 12.2 kg of body weight [BW])were randomly divided(2 × 2 factorial arrangement)into four treatments: control;CFA(0.1 mg/kg BW of FA from CFA);CSS(0.3 mg/kg DM of Se from CSS)and CFA + CSS(same with CFA group and CSS group).Dry matter intake(DMI)was increased with the supplementation of CFA(P<0.05)but was not affected by CSS addition.Average daily gain(ADG)was increased with CSS or CFA supplementation(P<0.05).Lower feed conversion ratio(FCR)was observed for both supplements.Supplementation with CFA increased digestibility of dry matter(DM),organic matter(OM),ether extract(EE)and neutral detergent fibre(NDF)(P<0.05),and reduced urinary nitrogen and total nitrogen(TN)excreted(P<0.05).Supplementation of CFA increased total volatile fatty acids(TVFA),acetate molar proportion,microbial proteins(MCP)and acetate to propionate ratio(P<0.05),and reduced propionate molar proportion(P<0.05).Activity of xylanase,pectinase,α-amylase and protease was higher for both supplements(P<0.05).Supplementation of CFA increased population of Prevotella ruminicola and supplementation of CSS reduced population of Ruminobacter amylophilus(P<0.05).Supplementation with CFA reduced serum urea nitrogen(P<0.05).Supplementation with CSS increased(P<0.05)serum homocysteine(Hcy),growth hormone(GH)and insulin-like growth factor-1(IGF-1).The expression of genes related to protein synthesis in the liver was not affected by treatments.Level of insulin-like growth factor-1 receptor(IGF-1R),mammalian target of rapamycin(m TOR)and ribosomal protein S6 kinase B1(P70S6K)in longissimus dorsi was increased by CSS supplementation(P<0.05).Dietary CFA supplementation increased phosphoinositide 3-kinase(PI3K),m TOR,and P70S6 K level(P<0.05).In this study,higher(P<0.05)CP and ADF digestibility,nitrogen intake,digestible nitrogen(DN),nitrogen retained(RN),population of Ruminococcus albus,Ruminococcus flavefaciens,Fibrobacter succinogenes and Butyrivibrio fibrisolvens,and lower(P<0.05)ruminal p H and ammonia nitrogen were observed for single addition of CSS compared with the combined addition of CFA and CSS.The data indicated that dietary CFA or CSS supplementation improved growth performance and ruminal fermentation in dairy calves,the combination of CFA and CSS was not found to be more effective than single CFA and CSS supplement.