LAUSR

5-HTP is the primary product that L-tryptophan converted into 5-HT by rate-limiting enzyme. Our previous study found that 5-HTP could promote intracellular calcium level in goat mammary epithelial cells (GMECs). Herein, dairy goats were injected with 5-HTP or saline daily from 7 days before delivery firstly, and the calcium level in colostrum of 5-HTP injected goats was significantly higher than saline injected goats. Moreover, miR-99a-3p expression was significantly increased after 5-HTP treatment from transcriptome sequencing analysis and RT-qPCR. Besides, it was found that ATP2B1 is one of the target genes of miR-99a-3p predicted by bioinformatic methods, which plays a crucial role in the maintenance of intracellular calcium homeostasis of mammary epithelial cells. Next, we confirmed that miR-99a-3p could increase intracellular calcium level via decreasing ATP2B1 in GMECs. Taken together, we draw the conclusion that 5-HTP promotes calcium level in colostrum possibly by increasing intracellular calcium of mammary epithelial cells induced by miR-99a-3p/ATP2B1 axis.