PRE-MATING AND POST-MATING DIETARY-SUPPLEMENTS OF FOLIC-ACID AND UTERINE SECRETORY ACTIVITY IN GILTS

The present study was carried out to determine the effects of pre- and (or) post-mating dietary supplements of folic acid on uterine secreti ons and secretory activity on day 12 of gestation. Crossbred gilts wer e assigned randomly to three treatments: SS) a dietary supplement of 1 5 mg of folic acid kg(-1) of diet from the estrus before mating (appro ximately day-21) until day 12 of gestation (n = 9), 0S) the same folic acid supplement from mating (day 0) to day 12 of gestation (n = 10), and 00) no supplement of folic acid (n = 10). At slaughter (day 12 of gestation), one uterine horn was flushed with 20 mL of PBS to collect embryos and uterine flushings, while samples of uterine tissue were co llected from the other hem. Supplementary folic acid (0S and SS) incre ased total folates in uterine flushings (P less than or equal to 0.05) as well as concentrations of folates in the endometrium (P less than or equal to 0.0004) and in the whole uterine tissue (endometrium + myo metrium: P less than or equal to 0.0001). Total amounts of prostagland in (PG)E-2 and PGF(2 alpha) in uterine flushings were not affected (P greater than or equal to 0.8) by any treatment but estradiol-17 beta w as numerically 40% lower (P greater than or equal to 0.12) in uterine flushings of 0S and SS sows. Samples of endometrium (15-17 mg) were cu ltured for 2 to 7 h. Concentrations of PGE(2) and PGF(2 alpha) in the culture medium increased with the duration of incubation (P less than or equal to 0.0001) but there was no treatment effect (P greater than or equal to 0.4). The inconsistency between the folic acid response se en in the present study and in previous results using multiparous sows suggests that the impact of this vitamin on sow reproduction might be linked to the parity (and/or prolificacy) of the animal.