Nutrient and energy digestibility, and microbial metabolites in weaned pigs fed diets containing Lactobacillus–fermented wheat

Abstract

The objective of this study was to investigate the effects of nursery diets containing fermented wheat, with or without enzyme complex, on nutrient and energy digestibility as well as microbial metabolites in weaned pigs. Wheat was fermented using either L. plantarum (Homo) or L. buchneri (Hetero), with or without an enzyme complex (multicarbohydrases + phytase) for a 90-d of period. The Homo produces lactic acid during fermentation whereas Hetero can further convert the lactic acid into volatile fatty acids and alcohol. Control diets were formulated with unfermented wheat without (negative control) or with (positive control) 0.5 g/kg of the enzyme complex whereas the treatment diets contained fermented wheat at 437.5 g/kg without enzymes. A casein (50 g/kg)-corn starch-based diet was used to estimate the basal endogenous amino acids losses. Fourteen weaned piglets (7.8 ± 0.3 kg initial body weight) were surgically fitted with a T-cannula at the distal ileum and allocated as per an incomplete replicated 7 × 3 Latin square design with 7 dietary treatments and 3 periods. The inclusion of fermented wheat increased (P < 0.05) the coefficient of apparent ileal digestibility (CAID) of GE and starch, and coefficient of apparent total tract digestibility (CATTD) of dry matter (DM), organic matter (OM), gross energy (GE), and phosphorus. Further, pigs fed fermented wheat diets showed greater (P < 0.05) CAID of methionine, cysteine, and tyrosine, and coefficient of standardized ileal digestibility (CSID) of methionine, alanine, and proline than those fed unfermented wheat diets. Pigs fed Hetero-fermented wheat diets demonstrated greater (P < 0.05) CAID of DM, OM, and GE, and CATTD of calcium and phosphorus than those fed Homo-fermented wheat diets. However, no differences in amino acids digestibility were observed between the inoculants. The addition of an enzyme complex for wheat fermentation increased (P < 0.05) the CATTD of calcium and phosphorus; the CAID of isoleucine, phenylalanine, valine, and tyrosine; as well as the CSID of isoleucine, phenylalanine, valine, and tyrosine. However, any changes in the volatile fatty acids and lactic acid concentrations and pH of the feces or the ileal digesta were not observed among treatment. In conclusion, feeding a nursery diet comprising fermented wheat increased the nutrient and energy digestibility. Inoculating wheat with Hetero is more beneficial than inoculating it with Homo in terms of energy and mineral digestibility. The addition of an enzyme complex to wheat fermentation increased mineral and amino acids digestibility.