Effects of corn DDGS in combination with compound enzymes on growth performance, carcass fat quality, and plasma and tissue redox homeostasis of growing-finishing pigs

The trial was conducted to investigate effects of corn dried distillers grains with soluble (DDGS) and compound enzymes on growth performance, carcass fat quality, and plasma and tissue redox homeostasis in growing-finishing pigs. 200 Pigs (Duroc×Landrace×Yorkshire, about 30 kg BW) were randomly allotted to one of four treatment groups (5 pens/treatment and 10 pigs/pen). The control (T0) was fed a basal corn-soybean meal diet. Treatment 1 (T1), 2 (T2), and 3 (T3) were fed corn-soybean meal-DDGS diets, with 10% corn DDGS in growing phase and 15% in finishing phase, respectively. 0.2 g/kg compound enzymes were added to the diets of T2 and T3 and digestible energy (DE) level of T3 was reduced 0.21 MJ/kg. The results of growth performance showed that all groups had comparable (P>0.05) results on ADG (682.15 g, 671.99 g, 709.28 g, 700.29 g), ADFI (2.00 kg, 2.02 kg, 2.04 kg, 2.10 kg) and feed conversion ratio (2.94, 3.01, 2.88, 3.00). Nevertheless, DDGS containing diets significantly increased iodine value (P<0.05) and decreased fat melting point of backfat and belly fat (P<0.05). For backfat and longissimus muscle (LM) intramuscular fat, DDGS containing diets increased unsaturated fatty acids (UFA) content (especially oleic acid and linoleic acid) (P<0.05), while decreased saturated fatty acids (SFA) content (especially palmitic acid and stearic acid) (P<0.05) and SFA:UFA ratio (P<0.05). Furthermore, DDGS containing diets reduced antioxidant activity of plasma and tissue. The activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and total antioxidative capacity (T-AOC) of plasma decreased in T1, T2 and T3 compared to T0, while malondialdehyde (MDA) content increased, especially in T3 (P<0.05). DDGS containing diets slightly decreased the activity of GSH-Px, SOD and T-AOC in liver and cardiac muscle (especially T3), while increased MDA content of kidney and spleen significantly (P<0.05). In conclusion, although there were no negative effects on the growth performance of growing-finishing pigs, DDGS containing diets decreased carcass fat quality by increasing iodine value and UFA content in backfat and LM intramuscular fat and decreasing fat melting point and SFA:UFA ratio, and altered the redox homeostasis of plasma and tissue by increasing oxidant (MDA) content and decreasing antioxidant content. Furthermore, adding compound enzymes to DDGS containing diets tended to increase the ADG of growing-finishing pigs.