Effect of supplementing flushing diet with fish oil on reproductive efficiency of Chaal ewes after laparoscopic artificial insemination

The beneficial effects of adding supplemental polyunsaturated fats including omega-6 and omega-3 sources to the diet on reproductive performance of livestock have been shown in many studies. On the other hand, low performance of artificial insemination is a serious problem to perform genetic improvement projects in sheep. Special effect of adding fish oil as an omega-3 source to flushing diet on reproductive efficiency of ewes after laparoscopic artificial insemination has not been investigated. The aim of this study was to investigate the effect of supplementing flushing diet with fish oil on reproductive efficiency of Chaal ewes after laparoscopic artificial insemination.
One hundred eleven of non-lactating and non-pregnant Chaal ewes, were divided into three experimental groups based on flushing diets: (1) negative control group (C-), fed the flushing diet without any supplemental fat, (2) positive control group (C), fed the flushing diet containing 3.5% supplemental hydrogenated palm oil (palm fat powder) and (3) fish oil group (FO), fed flushing diet containing 3.5% fish oil. Estrus synchronization of ewes performed using progesterone sponges for 13 days. Twenty to 48 hours after sponge removal, the rate of estrus recorded using rams with aprons and marking harnesses. Forty eight hours after sponge removal, artificial insemination was performed with the laparoscopic approach. Fifteen days after artificial insemination, to determine estrus non return rate and for mating of non-pregnant ewes, the rams with marking harnesses were introduced into the flock. Forty days after insemination, pregnancy diagnosis was performed by ultrasonography. At the time of lambing, number and weight of born lambs and three months later, the number and weight of weaned lambs were recorded for each ewe in experiment and using them reproductive traits including pregnancy, parturition, abortion, stillbirth, barren and multiple lambing rates, prolificacy, fecundity, born lamb crop, lamb viability, weaning rate and weaned lamb crop (ewe productivity) were calculated.
Adding fish oil to flushing diet significantly increased the weaning rate from laparoscopic artificial insemination and accumulated weaning rate from artificial insemination and natural mating (P0.05). In the group fed hydrogenated palm oil, lamb viability until weaning time was significantly (P In the programs of artificial insemination and synchronized natural mating of sheep, adding fish oil to flushing diet can improve reproductive performance. It is recommended that avoid using hydrogenated palm oil in flushing diet of sheep.