Evaluation of twice decorticated sunflower meal as a protein source compared with soybean meal in pig diets

A series of four experiments was conducted to compare nutritional values of decorticated sunflower meals against soybean meal, in diets for pigs from weaning (Exp. 1 and 2) to finishing (Exp. 3 and 4). All experimental diets were prepared compensating for the energy content by using vegetable oil and the lysine content was matched using synthetic L-Lysine HCl. Twenty-one day old pigs were fed either corn-soybean meal based diet (CSBM) or corn-twice-decorticated sunflower meal based diet (CDSM) for four weeks (Exp. 1). There was no difference in performances between treatment groups. In Exp. 2, corn-non-decorticated sunflower meal based diet (CNSM) was added to the existing two treatments. Twenty-one day old pigs were fed three experimental diets for four weeks. Pigs fed CNSM had a lower weight gain and feed intake than other treatments (p<0.05). There was no difference between pigs fed CSBM and CDSM (Exp. 2). Growth performance of growing pigs was also greater (p<0.05) in pigs fed corn starch-twice-decorticated sunflower meal based diet (CSDSM) than pigs fed corn starch-non-decorticated sunflower meal based diet (CSNSM) during the eight week feeding trial (Exp. 3). There was no difference between pig fed corn starch-soybean meal based diet (CSSBM) and CSDSM (Exp. 3). In Exp. 4, growing pigs were fed three experimental diets (CSBM, CDSM, and barley-twice-decorticated sunflower meal based diet; BDSM) until the slaughter. There was no difference in growth performance of pigs during growing and finishing periods among treatments. However, pigs fed CSBM had a higher carcass dressing percentage (p<0.05) than pigs fed CDSM and BDSM. Pigs fed BDSM diet had a lower fat tissue percentage than other groups (p<0.05). The twice-decorticated sunflower meal can be used as a substitute for soybean meal in pig diets. The performances of piglets and growing-finishing pigs were not affected when soybean meal was replaced by twice-decorticated sunflower meal. This substitution needs the contribution of synthetic lysine and vegetable oil as sources of complementary nutrients to match the nutrient profile.