Glucose Oligosaccharide and Long-Chain Glucomannan Feed Additives Induce Enhanced Activation of Intraepithelial NK Cells and Relative Abundance of Commensal Lactic Acid Bacteria in Broiler Chickens.

Nathalie Meijerink,J Arjan Stegeman,Victor P M G Rutten,Jean E De Oliveira,David M Lamot,Guilherme Hosotani,Christine A Jansen,Daphne A Van Haarlem

doi:10.3390/vetsci8060110

Abstract

Restrictions on the use of antibiotics in the poultry industry stimulate the development of alternative nutritional solutions to maintain or improve poultry health. This requires more insight in the modulatory effects of feed additives on the immune system and microbiota composition. Compounds known to influence the innate immune system and microbiota composition were selected and screened in vitro, in ovo, and in vivo. Among all compounds, 57 enhanced NK cell activation, 56 increased phagocytosis, and 22 increased NO production of the macrophage cell line HD11 in vitro. Based on these results, availability and regulatory status, six compounds were selected for further analysis. None of these compounds showed negative effects on growth, hatchability, and feed conversion in in ovo and in vivo studies. Based on the most interesting numerical results and highest future potential feasibility, two compounds were analyzed further. Administration of glucose oligosaccharide and long-chain glucomannan in vivo both enhanced activation of intraepithelial NK cells and led to increased relative abundance of lactic acid bacteria (LAB) amongst ileum and ceca microbiota after seven days of supplementation. Positive correlations between NK cell subsets and activation, and relative abundance of LAB suggest the involvement of microbiota in the modulation of the function of intraepithelial NK cells. This study identifies glucose oligosaccharide and long-chain glucomannan supplementation as effective nutritional strategies to modulate the intestinal microbiota composition and strengthen the intraepithelial innate immune system.

Highlights

Restrictions on the use of antibiotics in the poultry industry encourage the development of new strategies to maintain or improve poultry health such as nutritional solutions [1,2]
Based on the most interesting numerical results of these studies and highest potential to be produced in large scale, two polysaccharides were selected and supplemented to the diets of broiler chickens directly post-hatch to study their effects on natural killer (NK) cells and microbiota composition until three weeks of age
Stimulation with 57 compounds resulted in enhanced surface expression of CD107 on NK cells compared to the solvent control (Supplementary Materials Figure S1)

Summary

Introduction

Restrictions on the use of antibiotics in the poultry industry encourage the development of new strategies to maintain or improve poultry health such as nutritional solutions [1,2]. Nutritional modulation of innate immune responses is likely to be most beneficial for the health of chickens during the first week of life, since a high susceptibility to disease due to an immature adaptive immune system [7]. Identification and use of feed additives that either modulate the immune system directly or indirectly through changes in the microbiota may contribute to improved resistance against pathogens during the early life of chickens. Feed modulation was shown before to increase resistance to pathogens by activation of macrophages and subsequent adaptive reactivity [1,14,15] Both IL-2Rα+ and 20E5+ NK cells were shown to be important in the first response to viral [16,17,18] and Salmonella enteritidis [19] infections in chickens

Methods

Results

Conclusion