SPECIAL STORY FEED & ADDITIVE MAGAZINE June 2022 61 ducted. Nguyen et al. also showed that more soluble NSP in the diet means lower pH in the lower gut, reflecting more fermentation of carbohydrates into SCFA, giving less opportunity for pathogenic bacteria to establish as described previously by Apajalahti (2005). When calculating the total feed fibre composition from the diets reported by Nguyen, using the values reported in the Fibre Guide (AB Vista), it was possible to isolate the effects of the different soluble NSPs and the main driver for SCFA production was the soluble Arabinose + Xylose fraction while the other soluble components had limited or even negative effect in terms of fibre fermentability. These results reinforce that beyond the relevance to look at NSP solubility, it’s also important to look at the different components within this fraction. Researchers from the Universitat Autonoma de Barcelona used the AB Vista FQS NIR calibrations to explore the nutrient variability depending on the genetics of 8 maize hybrids as well as position of the grains in the cob (basal, well developed grains versus apical, less well-developed grains; Melo-Duran et al., 2021). Interestingly, in the majority of the criteria evaluated, there was an interaction between the genetic and the position of the grain (apical vs basal), often indicating poorer feeding value of the apical grains but for some of the hybrids there were minor differences between apical and basal grains, suggesting that those hybrids would give less variability in a grain crop. Regarding fibre, a large variation was also observed for total and soluble NSPs including the arabinoxylan (AX) concentration. Although the AX concentration in maize is low compared to other cereals this work showed that genetics can play an important role with a range from 2.2 g/kg to 5.3 g/kg AX. This explains why some corns could behave like wheats in terms of viscosity but also highlights why the effect of xylanase in corn-based diet can fluctuate. Xylanase and even more a stimbiotic product through the arabino xylo-oligosaccharides (AXOS) and xylo-oligosaccharides (XOS) production would be beneficial in bringing soluble compounds able to modulate the microbiome in the caeca. Relevance of a β-glucanase in highly viscous diets (containing both β-glucan and AX) is being questioned. β-glucanase, although reducing the viscosity and the molecular weight of β-glucan, did not affect the fermentation or the production of SCFA (Karunaratne
RkJQdWJsaXNoZXIy MTUxNjkxNQ==