1Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
2Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
3Research Center for Agriculture and Natural Resources of Golestan Province, Gorgan, Iran
The present study evaluated the effects of diets enriched in saturated and polyunsaturated fatty acids (n-3 and n-6) on reproductive indices, metabolic hormones and metabolites prior to ram introduction in oestrus synchronized ewes. Zel ewes (n=188) were assigned to 4 groups. Ewes in the control group (CON) did not receive fat. Ewes in the 3 other groups received 3% oil/DM/day of palmolein oil (PLM), safflower seed (SAF), or flaxseed (FLX). Fat supplementation was carried out for 31 days (day 0 = initiation of fat supplementation). Oestrus was synchronized using CIDR for 14 days starting from day 16 of fat supplementation. Rams were introduced 24 h after CIDR removal. Blood samples were collected on days 0, 30, and 39. There was no difference in oestrus expression and mating parameters among groups. There was no difference in non-esterified fatty acids (NEFAs), insulin and insulin-like growth factor-1 (IGF-1) between day 0 and day 30 among groups. However, changes in cholesterol and LDL concentrations during the same occasions were greater in PLM, SAF, and FLX groups than in CON (P<0.05). There was no difference in reproductive indices, including: fertility rates, prolificacy and sex ratio of lambs among groups. In conclusion, diets enriched in n-6 and n-3 polyunsaturated fatty acid prior to mating did not affect reproductive performance, insulin, IGF-1 and progesterone in Zel sheep.