The addition of n-3 polyunsaturated fatty acids (PUFA) to the diet of ruminants can benefit the reproductive
process in the female. The current study was conducted to assess the effect of a short period
of feeding a diet that included fish meal and oil on the progesterone (P4) and insulin (INS) profile, and on
reproductive variables including estrous onset, pregnancy and prolificacy in virgin ewes artificially inseminated
by laparoscopy (AIL). Forty-two Dorset ewes were assigned into two experimental groups:
These groups were no supplementation and a group supplemented with fish meal and oil
Ewes were fed the experimental diets for 15 days, beginning four days before
inserting sponges for estrus synchronization and ending the day the vaginal sponges were removed. Each
ewe received 0.8 kg d1 feed in individual pens. Ewes were pre-synchronized with prostaglandin F2α and
later synchronized with chronolone sponges for 11 days. When sponges were removed, the ewes received
200 IU of eCG. The AIL began 48 h after sponge removal and estrus detection. The time of estrus
onset was different among groups (Po0.05; CON: 35.172.1; FMO: 41.071.8 h). No differences were
found in P4
or INS concentrations in
. Adding fish meal and oil to the diet did not affect pregnancy percentage
but it did affect the prolificacy index. It was
concluded that the addition of fish meal and oil to the diet of virgin ewes over a short period time
delayed onset of estrus and enhanced prolificacy.