Extra dietary starch in late-pregnant sows fed a high fibre diet: effect on litter weight at birth

An experiment with 141 multiparous pregnant sows was conducted to investigate whether the supply of glucogenic energy at the end of pregnancy may be insufficient for an optimal growth of the foetuses in sows that are fed a diet with a high level of non-starch polysaccharides (NSP) and low level of starch. Sows were fed one of three diets from day 85 of pregnancy until parturition: : :Sows were fed a high NSP low starch diet. The daily intake of starch and sugar was 500 g. : :Sows were fed the same diet in the same amount as the sows in treatment 1 plus an extra daily amount of 500 g starch from wheat starch (is glucogenic energy). This means that the sows were fed 0.58 kg/d extra wheat starch (is 6.73 MJ glucogenic NE) during the last month of pregnancy. : :Sows were fed the same diet in the same amount as the sows in treatment 1 plus an extra daily amount of 200 g soya oil (is 6.73 MJ lipogenic NE). This treatment was added because otherwise it will not be clear whether energy or glucogenic energy is thelimiting factor. : :From day 1 of day 85 of pregnancy all sows were fed the high NSP low starch diet. During lactation all sows were fed the same lactation diet. Effects on litter performance, on changes in body weight and backfat thickness of the sows, and on feed intakeduring lactation were studied. The supply of extra dietary starch or extra dietary fat in late-pregnant sows that were fed a high NSP low starch diet did not increase litter weight at birth. This suggests that sows that were fed the high NSP low starch diet received sufficient glucogenic energy for foetal development. : :The number of stillborn piglets was numerically higher in sows that received extra dietary fat at the end of pregnancy. Sows that were fed extra dietary starch or extra dietary fat increased more in weight and backfat thickness during late pregnancy than sows that were fed the high NSP low starch diet. Decreases in weight and backfat thickness during lactation were similar for the three experimental treatments. Voluntary feed intake during lactation was slightly decreased in sows that were fed extra starch or extra fat in late pregnancy. :The present study shows that late-pregnant sows can be fed a high NSP low starch diet without adverse effects on litter weight at birth. A daily intake of 500 to 600 g starch and sugar in latepregnant sows seems sufficient for optimal growth of the foetuses.