The different effects of linseed and fish oil supplemented diets on insulin sensitivity of rabbit does during pregnancy

This study investigates the effects of linseed (rich in ɑ-linolenic acid (ALA)) and fish oil (rich in eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) supplementation on the insulin resistance of pregnant rabbits. Two months before insemination, the rabbits (15 animals/group) were fed different diets: commercial standard (group C), supplemented with 10% extruded linseed (group L), and 3% fish oil (group FO). The L group does showed both the highest feed intake before AI (P < 0.01) and the highest body weight (BW) throughout pregnancy (P < 0.001). The L does yielded less milk than the C does (P < 0.001); however, no differences were observed in either weight or size of litter at weaning. Regardless of diet, insulin concentrations and HOMA-IR values were higher during the first half of pregnancy (P < 0.001). Nevertheless, the L does showed higher mean insulin concentrations than FO rabbits (P < 0.01) and the lowest glucose clearance (P < 0.01) during pregnancy. On the other hand, pregnant FO rabbits showed the lowest glucose concentrations (P < 0.05) and the lowest Homeostasis model assessment values for insulin resistance (HOMA-IR, P < 0.05) as well as a faster restoration of baseline glucose levels following glucose load (P < 0.001). Before and during pregnancy, the BW of the rabbits was positively related to fasting sample- and tolerance test-derived indices of insulin resistance (P < 0.05) suggesting that a high pre-pregnancy BW predisposes to gestational insulin resistance. Linseed supplementation increased BW and predisposed to insulin resistance during pregnancy; whereas, fish oil improved insulin sensitivity without significant changes in BW.