Effects Of Dietary 25-hydroxycholecalciferol Supplementation On Reproductive Performance Of Gilts

1,25-Dihydroxyvitamin D₃is the most important active form of VD₃in the animal body,responsible for exercising most of its biological functions,the reproductive performance of the gilts directly affects the gilts lifelong production performance,the level of gilts fertility is crucial to the production of farms and economic benefits.This study was conducted to evaluate the effects of dietary hydroxy cholecalciferol（25-OH-D₃）supplementation on reproductive performance of gilts.Twenty gilts with an initial age about 170d and body weight about 70kg were randomly allotted to one of two groups(the diets of control group contained 50μg/kg vitamin D₃and the diets of 25-OH-D₃supplemented group（HYD）contained additionally 50μg/kg（25-OH-D₃）,and each group had ten repetitions（gilts）.This study ended on d28 of lactation（weaning）.Results showed as follows:supplementation of 25-OH-D₃in diets of gilts significantly increased serum 25-OH-D₃concentrations of gilts,umbilical cord and newborn piglets（P<0.05）,while had no significant effect on 25-OH-D3 concentrations of weaning piglets（P>0.05）;Dietary 25-OH-D₃supplementation did not significantly influence body weight,backfat thickness change and feed intake of gilts during experimental period（P>0.05）;Compared with control group,HYD gilts had a trend of elevated body weight at first observed estrus（P=0.08）,significantly delayed age at first observed estrus and increased the rate of standing estrus（P<0.05）;Compared with control group,HYD gilts gave birth to 1.2 more piglets（P<0.05）and 1 more piglet alive（P<0.05）.However,the body weight of newborn piglets and litter weight were not significantly influenced by dietary 25-OH-D3 supplementation（P>0.05）;On d110 of gestation and at weaning,the activities of serum bone formation maker-alkaline phosphatase（AKP）was significantly increased in HYD gilts compared with control group（P<0.05）.Moreover,on the d21（P=0.06）,d90（P=0.08）of gestation and at farrowing（P=0.06）,HYD gilts trended to have higher serum AKP activities than control gilts.However,dietary 25-OH-D₃supplementation did not significantly seriously influence serum bone degradation maker-tartrate-resistant acid phosphatase（TRAP）activities of gilts during experimental period（P>0.05）。In conclusion,Dietary supplementation of 25-OH-D₃significantly improved vitamin D status of gilts,delayed first observed estrus and increased rate of standing estrus,increased litter size,improved milk quality and piglets growth performance,and promoted bone formation and improved bone status,and then improved reproductive performance of gilts。...