The combination of carbohydrases and phytase to improve nutritional value and non-starch polysaccharides degradation for growing pigs fed diets with or without wheat bran

Abstract

The objective of this experiment was to determine the effects of supplementation of phytase and carbohydrases individually or in combination on digestibility of proximate constituents, amino acids (AA), phytic acid and non-starch polysaccharides (NSP) at different intestinal sites in growing pigs fed diets with or without wheat bran (WB). Sixteen pigs (initial body weight: 18.12±0.74kg) surgically equipped with a T-cannula in the distal ileum were randomly assigned to 8 diets, in a 2×2×2 factorial arrangement including phytase (0 vs. 1000 FTU/kg), carbohydrases (0 vs. 300mg/kg), and WB (0 vs. 20%). Pigs were arranged in a doubly replicated 8×3 incomplete Latin square design (8 diets with 3 periods) with 6 pigs per treatment. Each period lasted 7-d. Feces were collected on d 5 and ileal digesta were collected on d 6–7. Regardless of WB addition, phytase supplementation improved (P<0.05) AID and ATTD of ash, calcium, and total phosphorus, as well as AID of phytic acid, threonine, aspartic acid, and glycine. For pigs fed diets with phytase, supplementation of carbohydrases increased (P<0.05) AID of phytic acid only in WB diets, but not in WBF diets. There were interactions effects (P<0.05) between WB and carbohydrases on AID of histidine, isoleucine, lysine, threonine, aspartic acid, glycine, serine, dry matter (DM), energy, crude protein (CP), neutral detergent fiber (NDF), and NSP constituents, as well as ATTD of DM and CP. They were improved (P<0.05) by supplementing carbohydrases in WB diets, whereas, no positive effects were observed in WBF diets. Furthermore, the addition of carbohydrases to WB diets improved (P<0.05) AID of NSP and its constituents, but ATTD of NSP were not affected by carbohydrases inclusion. In conclusion, carbohydrases improved digestibility of energy, proximate constituents, AA, phytic acid, and NSP in the ileum for pigs fed WB diets, but did not affect the ATTD of energy and NSP constituents. The magnitude of phytase and carbohydrases supplementation on nutrient digestibility depended on the addition of WB.