Effects Of Vitamin A On Growth Performance,Blood Biochemistry Indices And Intramuscular Fat Deposition Of Lactati On Tan Lambs

Intramuscular fat was closely related to juiciness,tenderness and flavor of meat.The development of adipose tissue cells in different parts of ruminant livestock was different,and the proliferation of intramuscular adipose cells was mainly concentrated from around birth to weaning(the critical window for intramuscular adipose development).In this study,Tan lambs were used to investigate the effects of vitamin A on the growth performance,blood biochemistry Indices and intramuscular fat deposition during the critical window of intramuscular adipogenesis.Sixty multiparous Tan sheep ewes with similar health,parity and body weight[(46.83±1.3)kg]were selected for simultaneous estrus and artificial insemination.After delivery,45 healthy tan lambs with similar birth date and weight[(4.38±0.23)kg]were selected and randomly divided into 3 groups,each group had 3 repetitions(pen),and each repetition had 5 lambs.On the basis of normal breastfeeding(control group),30 000 IU(30 000 IU group)and 60 000 IU(60 000 IU group)of vitamin A were administered at 1 day and 1 month of age,respectively.The experiment lasted for 70 days.The results showed that:1.There were no significant differences in birth weight and chest circumference among the three groups;The daily gain and weaning weight of lambs treated with 30 000 IU and 60 000 IU vitamin A were significantly higher than those in the control group(P<0.05);Body height and body length of lambs in vitamin A groups showed an upward trend(0.05≤P<0.10).2.Compared with the control group,the contents of serum total cholesterol,triglyceride,low density lipoprotein,total antioxidant capacity,superoxide dismutase activity and immunoglobulin A were significantly greater(P<0.05),whereas the content of malondialdehyde was significantly lower in 30 000 IU and 60 000 IU vitamin groups(P<0.05).The contents of total protein,glutathione peroxidase and interleukin-6 β in serum were significantly increased(P<0.05),while the content of urea nitrogen was significantly decreased in 30 000 IU group(P<0.05).3.Compared with the control group,the serum retinoic acid content in 30 000 IU and 60 000 IU groups was significantly increased(P<0.05),and the serum retinol content in 60 000 IU group was significantly decreased(P<0.05);The mRNA relative expression levels of zinc finger protein 423(ZFP423)and peroxisome-proliferating-activated receptor y(PPARy)in longissimus dorsi muscle in 30000 IU group were significantly increased(P<0.05),while the mRNA relative expression of ZFP423 in longissimus dorsi muscle in 60 000 IU group was significantly increased(P<0.05).In conclusion,hupplement of 30 000IU and 60 000IU of vitamin A at 1 and 30 days of age could significantly improve the growth performance,serum retinoic acid content and the expression of genes related to Intramuscular fat deposition of lactating Tan lambs,and improve the body’s antioxidant stress and immune capacity.The recommended dosage is 30000IU.