Effects of supplying omega-3 polyunsaturated fatty acids to gilts after weaning on metabolism and ovarian gene expression.

Omega-3 polyunsaturated fatty acids (PUFA) may benefit sow reproductive performance, but effects on weaned gilts are unknown. This study evaluated the effects of supplementing omega-3 PUFA to gilts after weaning on growth, metabolic markers and gene expression of steroidogenic enzymes and hormone receptors. For 52 d, gilts in the control group were fed 100 g/d of regular diets, whereas gilts in the omega-3 group were fed 75 g/d of such diets plus 25 g/d of the microalgae Schizochytium sp. (3.5 g/d of omega-3 PUFA) (n = 8 gilts/group). Blood samples were collected at D0, D21 and D52. Total serum cholesterol levels were lower for the omega-3 group than for the control (P < 0.05), but HDL-cholesterol levels were reduced at D52 for both groups (P < 0.05). Gilts in the omega-3 group presented lower feed intake, better feed conversion and less intense immunolabeling for leptin and its receptor in the cytoplasm of oocytes included in primordial/primary follicles than control gilts (P < 0.05). The expression of genes coding for cholesterol side-chain cleavage and aromatase enzymes and the LH receptor in follicular cells was lower for supplemented gilts (P < 0.05). Compared to controls, supplemented gilts presented decreased serum cholesterol levels and better feed conversion, but leptin presence and gene expression for steroidogenic enzymes and for the LH receptor were lower at ovarian level.