Polyunsaturated Fatty Acids Combined with Equine Chorionic Gonadotropin to Enhance Reproductive Performance in Aged Rabbit Does

Abstract

Sixty low-conception rate does aged 18 to 24 months (in four groups) were used to determine the effect of replacement of prostaglandin (PG) F2α (PGF2α) injection by oral administration with sunflower oil (Sun) (rich in omega 6) or linseed oil (Lin) (rich in omega 3) on reproductive and productive performance. Group 1 was injected with 20 U of equine chorionic gonadotropin (eCG), 54 h before artificial insemination (AI) and used as reference group. Group 2 was injected with 20 U of eCG+0.5 mg of PGF2α, 54 h before AI. Group 3 was orally given 3 mL of Sun/doe/day, for seven consecutive days before AI+20 U of eCG, 54 h before AI. Group 4 was treated like Group 3 except that the oil was Lin. Aged does treated with eCG+Sun had elevated blood 17-β estradiol concentration (P≤0.01) accompanied with a decrease of progesterone concentrations compared to the other experimental groups. Contrarily, no significant differences were found between eCG+Lin and eCG+PGF2α treatments on the previous two hormones. Likewise, aged does treated with eCG+Sun and eCG+Lin were statistically similar to those injected with ECG+synthetic PGF2α on blood prostaglandin profile, but still significantly higher than the control group. Treatment with eCG+Sun increased the percentage of fertile does (P≤0.01) and the litter size at birth compared to the other experimental groups. In conclusion, replacement of the PGF2α injection by oral administration of Sun or Lin to aged does improved sexual hormone synthesis and secretion, litter size and bunny body weight at birth.