Effects of oligosaccharides on performance, egg quality, nutrient digestibility, antioxidant status, and immunity of laying hens: a meta-analysis

Abstract

A meta-analysis was conducted to determine the effects of different types of oligosaccharides (OS) on the egg quality, intestinal profile, nutrient digestibility, and immunity of laying hens. A dataset was constructed from articles published between 2006 and 2023 via a literature search using several keywords related to oligosaccharides and laying hens’ performance. After careful evaluation, the final dataset was developed from 25 in vivo studies comprising 165 comparisons. The meta-regression showed that levels of OS supplementation curvilinearly increased (p < 0.05) hen day egg production (HDEP), and crude protein digestibility (CPD). However, OS supplementation did not affect (p > 0.05) feed intake (FI), feed conversion ratio (FCR), egg mass, egg weight, eggshell thickness, shell strength, and Haugh unit. OS supplementation showed a positively improved antioxidant activity, as indicated by the curvilinear effect on superoxide dismutase (SOD) and malondialdehyde (MDA) concentration. In the categorical meta-analysis, mannan oligosaccharide (MOS), xylooligosaccharides (XOS), and chitosan oligosaccharide (COS) significantly increased (p < 0.01) HDEP and CPD. MOS was the only type of OS that decreased (p < 0.05) FCR while FOS showed to increase (p < 0.01) Haugh unit. To sum up, oligosaccharides could generally increase HDEP but MOS is superior to improving HDEP and FCR while FOS is better than other OS to increase eggshell thickness. HIGHLIGHTS Oligosaccharides increase egg production and protein digestibility in laying hens. Mannan oligosaccharide improves feed conversion ratio in laying hens. Elevated trends of IgG and IgA after supplementation with oligosaccharides. Fructo-oligosaccharides improve eggshell thickness and suppress Malondialdehyde (MDA) in laying hens.