Simple SummaryNon-starch polysaccharides and phytate have been considered the most common antinutritional factors in feedstuffs, and there is no corresponding enzyme in animals. Our results showed that the multi-carbohydrase and phytase supplementation had a potent role in improving energy, amino acids, calcium, and phosphorus digestibility in fattening pigs regardless of dietary nutrient levels, thus increasing the deposition of calcium and phosphorus in bone and improving the growth rate and feed efficiency of fattening pigs. These findings have important implications for the application of multi-enzymes in fattening pigs to spare feed costs, reduce nutrient waste, and improve swine production efficiency.AbstractThis study was conducted to investigate the effects of dietary multi-enzyme (multi-carbohydrase and phytase complex, MCPC) supplementation on digestibility, growth performance, bone mineralization, and carcass yield and traits in growing–finishing pigs fed diets with adequate or deficient net energy (NE), amino acids (AA), calcium (Ca) and phosphorus (P) levels. A total of 576 crossbred [Duroc × (Landrace × Yorkshire)] barrows (~25 kg) were fed one of the six diets till live weight approached 130 kg. Basal diets included a positive control (PC), negative control 1 (NC1) and 2 (NC2), while another three diets were prepared by adding MCPC to the three basal diets. The final body weight was lower (p< 0.05) in NC2 than in NC1 and PC treatments, while overall feed intake and feed-gain ratio were higher (p< 0.05) in NC1 and NC2 than in PC treatment. The NC2 treatment showed lower (p< 0.05) carcass weight but higher (p< 0.05) lean meat percentage than the PC treatment. The apparent ileal digestibility (AID) of gross energy (GE), crude protein (CP) and AA was decreased (p< 0.05) or tended (p< 0.10) to decrease in NC1 and/or NC2 diets compared with a PC diet. MCPC supplementation improved (p< 0.05) AID of Ca, P and AA (Lys, Leu, Val, Phe, Gly, Tyr and Pro), apparent total-tract digestibility (ATTD) of GE, CP, bone strength, Ca, and P retention. In conclusion, MCPC supplementation improved nutrient digestibility, bone mineralization, and growth performance of fattening pigs, regardless of the nutritional level of the basal diet.