The Effect Of D₃ Hydroxylate On Reproductive Performance Of Sows

Vitamin D plays an important role in regulating and improving the reproductive performance of sows.It is closely related to the reproductive performance of male animals and can be used as a potential biomarker for evaluating the fertility of male animals.Vitamin D exists in two ways in the body.25-hydroxy D₃ and its further hydroxylated product 1,25-dihydroxy D₃ are involved in the regulation of fertilization,bone development and various complex physiological processes.However,there are few reports on the correlation of reproductive performance of sows directly fed with 25-hydroxy D₃.In this study,we first measured the production data of the sows after feeding 25-hydroxy D₃through animal experiments,and the reproductive performance indicators（21 days weaning weight,5,7 days estrus rate,breeding conception rate,piglet uniformity,etc.）A correlation analysis was conducted.Then,the colostrum was collected and the milk protein,lactose and milk fat were measured,and further added to the porcine mammary epithelial cell culture medium by adding 25-hydroxy D₃ and 1,25-dihydroxy D₃,and detecting by CCK-8 and Q-PCR techniques.Its effect on the activity of pig mammary epithelial cells and the expression of key genes regulating lactation.The main results are as follows:（1）After feeding 25-hydroxy D₃to piglets for 90 days during pregnancy,the estrus rate of the sows in the sows was significantly increased（P<0.05）;and the serum calcium and phosphorus ions were significantly increased（P<0.05）.It can significantly increase the content of milk fat in colostrum,the uniformity of piglets,the weight of 21 days of weaning,and the growth rate of piglets（P<0.05）.（2）25-hydroxy D₃ and 1,25-dihydroxy D₃ were added to the mammary gland epithelial cell culture medium at a concentration of 10^-7～10^-10mol/L,respectively,which significantly increased their cell viability（P<0.05）.When the concentration was 10^-9mol/L,the effect was the most significant.At the concentration of 10^-9mol/L,the expression of key genes SREBP1,LPIN1 and INSIG1 in lactation regulation network were significantly increased.The effect of 1,25-dihydroxy D₃ was more significant（P<0.05）.The above results indicate that feeding 25-hydroxy D₃ during the 90-day gestation period can improve the reproductive performance of the sows,improve the quality of the milk,and find that it may affect the regulation of lactation at the cellular level,in order to study the estrus of 25-hydroxy D₃ on the sows.Provide a basis for the effects of molecular mechanisms of lactation.