Maternal supplementation with calcium varying with feeding time daily during late pregnancy affects lipid metabolism and transport of placenta in pigs.

To investigate effects of Ca level varying with feeding time daily in sows during late pregnancy on placental lipid metabolism and transport in pigs, sixty pregnant sows were assigned to 3 groups: the CON group was fed low-Ca diet with 11.25 g CaCO3 at 0600 h and 1500 h, H-L group was fed low-Ca diet with 22.5 g CaCO3 at 0600 h and low-Ca diet at 1500 h, and L-H group was fed low-Ca diet at 0600 h and low-Ca diet with 22.5 g CaCO3 at 1500 h, respectively. Serum from sows and umbilical cord and placenta were collected during delivery. Results showed that, compared with the CON group, H-L feeding significantly increased maternal serum total triglyceride (TG) and umbilical serum high-density lipoprotein (HDL) (P < 0.05). The results showed that long chain fatty acid (FA) contents in placenta were significantly increased in H-L and L-H groups (P < 0.05). Experiments on genes involved in glycolipid metabolism showed that H-L or L-H feeding inhibited mRNA expression of GLUT3, GLUT4, FAS, FABP1, FABPpm, FAT/CD36, while activated the mRNA expression of FASD1, FASD2 and SCD in placenta (P < 0.05). In addition, experiments on genes involved in biological clock showed that L-H feeding sequence activated the mRNA expression of per1 and clock, while H-L and L-H feeding sequence inhibited mRNA expression of per2 in placenta (P < 0.05). It is concluded that maternal supplementation with Ca varying with feeding time daily during late pregnancy affects placental lipid metabolism and transport in pigs by regulating the mRNA expression related to lipid metabolism and the circadian clock.