Fermentation and addition of enzymes to a diet based on high-moisture corn, rapeseed cake, and peas improve digestibility of nonstarch polysaccharides, crude protein, and phosphorus in pigs

Fluctuating prices of cereals have led to an interest in alternative ingredients for feed. The aim of this study was to evaluate the effect of fermentation and the addition of nonstarch polysaccharide (NSP)-degrading enzymes on the ileal and total tract digestibility of nutrients of a diet based on locally grown crops. Four diets were fed including a nonfermented liquid standard grower diet (Control) and 3 experimental diets based on high-moisture corn, rapeseed cake, and peas fed as nonfermented liquid feed (nFLF), fermented liquid feed (FLF), or FLF supplemented with an enzyme mixture of beta-glucanase + xylanase + pectinase (FLF+Enz). The FLF was prepared by mixing feed and water (1:2.5, wt/wt) and, once daily, replacing 50% of the mixture with an equal amount of fresh feed and water. The diets were fed to 8 ileal cannulated barrows in a double Latin square design. Ileal digesta and feces were collected after an adaption period of 10 d. Results showed microbiologically good-quality fermented diets. The levels of Enterobacteriaceae were 5.1 to 5.4 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the ileum and 5.1 to 5.2 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the feces. Apparent total tract digestibility (ATTD) of CP was increased by fermentation (73.2% in FLF vs. 69.0% in nFLF; P = 0.033), and digestibility of P showed a tendency (P = 0.073) toward an increase. Addition of the enzyme mixture resulted in a pronounced reduction of dietary NSP compared with FLF (12.8% total NSP in FLF+Enz vs. 15.9% total NSP in FLF; P < 0.001), which also led to increased apparent ileal digestibility (AID) of total and insoluble NSP (total NSP, 31.1% in FLF+Enz vs. 13.6% in FLF; P = 0.002). The Control did not, in general, show higher digestibility values than the experimental diet. However, in the cases were it did, fermentation and enzyme addition brought the digestibility to the level of the Control. In conclusion, fermentation increased the ATTD of CP and the AID of P, with the same tendency (P = 0.07) for the ATTD. Addition of NSP-degrading enzymes resulted in a pronounced reduction in the concentration of NSP in the feed along with increased AID of NSP. Hence, the experimental diet seems to be a possible alternative to a traditional diet for pigs.