Vitamin A supplementation downregulates ADH1C and ALDH1A1 mRNA expression in weaned beef calves

Our previous studies demonstrated that oral vitamin A supplementation during late-stage pregnancy and the neonatal stage enhances birth weight,growth performance,and mRNA expression related to muscle and preadipocyte development in beef cattle.The alcohol dehydrogenase 1C(ADH1C)c.-64T>C genotype also correlated with vitamin A concentration in beef production.This study aimed to investigate the effects of vitamin A supplementation on the muscle development and vitamin A metabolism in weaned beef calves with different ADH1C genotypes.Twenty male calves(90 d of age;initial BW:89.03 kg[SD 8.60])were stratified according to ADH1C genotype and vitamin A treatment(duration:3 months)and randomly assigned to 4 groups with a 22 factorial arrangement.Vitamin A treatments included the following:control(10,000 IU/kg of as-fed,a.TT type;b.TC type);treatment(40,000 IU/kg of as-fed,c.TT type;and d.TC type).Parameters including BW,FI,blood,longissimus dorsi muscle,and liver status during the experimental period were analyzed using the generalized linear model(GLM)procedure and Tukey's test by SAS 9.4 program.Serum vitamin A was significantly increased(P<0.05)in the vitamin A treatment group at 4 and 6 months of age.TT type calves showed higher serum vitamin A concentration(P<0.05)than the TC type calves.Serum triglyceride and non-esterified fatty acid(NEFA)levels increased(P<0.05)in the treatment group compared with the control at 6 months of age.However,BW,ADG and FI showed no differences between the groups.In addition,mRNA expression in longissimus dorsi muscle revealed upregulation of paired box 7(PAX7)(P<0.05)after the vitamin A treatment period based on biopsy results.Both ADH1C and aldehyde dehydrogenase(ALDH)1A1 mRNA expression was downregulated(P<0.01)by vitamin A supplementation.The TC type of ADH1C showed higher mRNA expression than the TT type.However,no effect was observed on adipogenic mRNA expression(preadipocyte factor-1[PREF-1],peroxisome proliferator-activated receptor gamma[PPARg],fatty acid binding protein 4[FABP4])in all groups.Our findings suggest that weaned calves treated with vitamin A may promote the storage of satellite cells by elevating PAX7 gene expression in the muscle.The TC type calves may show increased capacity for vitamin A metabolism,which can be used in genetically customizing feed management to maximize beef production in the calves.