Co-products in maize-soybean growing-pig diets altered <i>in vitro</i> enzymatic insoluble fibre hydrolysis and fermentation in relation to botanical origin

Abstract

The study examined the effects of botanical factors and fermentation-based, high-level dilution of coproduct feeds in maize-soybean growing-pig diets on enzymatic insoluble fibre hydrolysis and fermentation. Feed insoluble fibre residues that were recovered after pepsin-pancreatin digestion were subjected to Roxazyme ® G2 (Roxazyme) versus Viscozyme L ® V2010 (control) hydrolysis, and to 64-hour fermentation using pig faecal inoculum. The control diet was a 13 MJ metabolizable energy, 141 g total dietary fibre/kg dry matter maize-meal/hominy chop-soybean diet, which was diluted with maize cob, soybean hulls, barley brewer's grains, lucerne hay or wheat bran in 12 MJ metabolizable energy, 246 g total dietary fibre/kg dry matter iso-nutrient, single co-product test diets. Fermentable insoluble fibre was employed in a computerized iterative selection of ingredients in two iso-nutrient 11 MJ metabolizable energy 319 total dietary fibre/kg dry matter mixed fibre test diets for maximal contrast (high (HF) versus low (LF)) in fermentability. Insoluble fibre extractive pepsin-pancreatin digestibility differed between feed ingredients, and the single co-product test diets, and between the HF and LF mixed co-product diets. Fibre digestibility depended on both the origin and enzyme, with interaction, whereby carbohydrases expressed similar low (0.04-0.05) insoluble fibre digestibility for maize cob, moderate (0.12) digestibility for wheat bran and brewer's grain, with inferior Roxazyme G2 digestibility for maize hominy chop (0.02 vs 0.10) and meal (0.04 vs 0.16), dehulled soybean meal (0.02 vs 0.17), lucerne hay (0.08 vs 0.18), and soybean hulls (0.05 vs 0.33). Co-product-enzyme affinities were expressed in single fibre diets. Low Roxazyme-basal fibre affinity limited its comparative single co-product (0.03-0.07 vs 0.16-0.22) HF (0.07 vs 0.17) and LF (0.4 vs 0.20) dietary fibre digestibility. Screening for HF/LF did not affect enzymatic digestion, though enzyme combination increased HF, but not LF digestibility. Gas and short chain fatty acid production predicted fermentability proportionately in the declining order of dehulled soybean ≥ maize ≥ soy hulls ≥ maize hominy chop > wheat bran >lucerne hay ≥ brewer's grain = maize cob. Induced HF and LF contrast was significant. Co-product fibre enrichment decreased fermentability for all except the soy hull and HF diets. Cereal fibre yielded proportionately less acetate, with more propionate and butyrate, and a greater butyrate shift for maize fibre. The HF fibre induced more ACE and less butyrate. Biomarkers of deleterious proteolytic fermentation were high for lucerne (isobutyrate) and soy hulls (iso-valerate). In conclusion, high-level and fermentation based co-product feed dilution into maize-soybean growing pig diets altered enzymatic insoluble fibre hydrolysis and fermentation in relation to botanical origin. Roxazyme expressed weak hydrolytic potency on maize and soybean insoluble fibre.

Nutrient digestibility and nitrogen balance in different pig breeds fed raw, sprouted, or roasted (Vigna unguiculata) diets

“…The DM for the RCP, SPC, or RSCP diets that escaped the foregut could be of variable bulkiness, which is known to influence gut emptying in growing pigs (Kyriazakis and Emmans, 1995 ). However, in vivo, less escape, particularly of fibrous matter, should be expected, since, compared to a commercial product such as Viscozyme, the greater diversity of pig gut microbial fibrolytic activity (Fushai et al, 2019 ) should confer higher digestibility of fibrous compounds in the colon. Fibrolytic advantage of the indigenous pig gut was previously reported from genomic evaluation of faecal microbiota (Kanengoni et al, 2015 ).…”

In Vitro-in Vivo Digestibility and Nitrogen Balance in Indigenous, Exotic and Crossbred Growing Pigs Fed Sprouted or Roasted Cowpea Diets

“…In contrast to in vitro digestion, roasting and sprouting compromised total in vivo apparent DM digestibility, which could re ect either disparate digestion and, or, the result of increased endogenous faecal excretion. Compared to a commercial product such as Viscozyme, greater diversity of pig gut microbial brolytic activity (Fushai et al, 2019) should confer higher true digestibility of brous plant embryonic secondary tissue in cowpea sprouts, and of crosslinked compounds in over processed roasted cowpeas. Tendency (P = 0.053) toward pig genotypic x diet interaction on DM digestibility was consistent with numerically greater Windsnyer pig capacity to digest sprouted cowpea dietary bre.…”

In Vitro Techniques Using the DaisyII Incubator for the Assessment of Digestibility: A Review

“…Fushai [128] determined, with an AD II incubator, the in vitro digestibility of growing pig diets supplemented with exogenous enzymes. Each feed was digested in pepsin, followed by pancreatin, with the recovery of the fibrous residues.…”