Effect of offering maize, linseed or tuna oils throughout pregnancy and lactation on sow and piglet tissue composition and piglet performance

The effects of different dietary essential fatty acids on piglet tissue composition at birth and performance until 7 days post weaning were investigated by offering the sow diets containing (17.5 g oil per kg diet) either maize oil (MO) as a control treatment, tuna oil (TO) as a source of long chain n-3 polyunsaturated fatty acids, particularly 22:6 n-3, or a mixture of maize and linseed oils (LO) which supplied the same amount of n-3 acids as TO but in the form of 18:3 n-3. Ten sows were allocated to each treatment which was offered throughout pregnancy and lactation. Compared with MO, offering TO increased sow plasma and subcutaneous adipose tissue 22:6 n-3 proportions whereas LO increased 18:3 n-3 and, to a much lesser extent than TO, 22:6 n-3. Offering TO to the sow increased the proportions of 20:5 n-3 and 22:6 n-3 in piglet brain and liver at birth and decreased the n-6 acids, 20:4, 22:4 and 22:5. LO only increased piglet liver 20:5 n-3 proportions but to a lesser extent than TO; however LO also decreased the proportions of 20:4, 22:4 and 22:5 n-6 in piglet tissues. Offering the pregnant sow dietary 18:3 n-3 therefore increased deposition of 22:6 n-3 in foetal piglet tissues to a much lesser extent than tuna oil and so it is necessary to offer the sow pre-formed 22:6 n-3 in order to achieve maximum foetal 22:6 n-3 deposition. By experimentally allocating piglets at birth, effects of sow nutrition during pregnancy and lactation were separated. Piglets sucking MO or TO sows were heavier than piglets sucking LO sows 7 days post weaning.