Effects of Methionine Deficiency on the B Lymphocyte and Immunoglobulins of Cecal Tonsil in Cobb Broilers

M Zhu,B Wu,T Ruan,Q Zeng

doi:10.1590/1806-9061-2019-1059

Abstract

ABSTRACT The present study was conducted on one-day-old broilers to investigate the effects of methionine deficiency on B lymphocytes and immunoglobulins (sIgA, IgA, IgG, IgM) in the cecal tonsil of Cobb broiler chicken. Methods including immunohistochemistry (IHC), western blot (WB), quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Enzyme-Linked Immuno Sorbent Assay (ELISA) were used, and the study lasted for 6 weeks. It was found that the IgA+ B lymphocytes mainly existed in the diffuse lymphoid tissues and lymphoid follicles of the cecal tonsil. The data indicated that the number of IgA+ B lymphocytes was decreased in the methionine deficiency group, and the WB and qRT-PCR results suggested that the protein and mRNA expression of CD19 were reduced in the methionine deficiency group. Besides, the contents of sIgA, IgA, IgG and IgM determined by ELISA decreased in the methionine deficiency group. It could be concluded that methionine deficiency exerts significantly negative effects on the humoral immune function of the intestinal mucosal immunity.

Highlights

The changes of B lymphocytes count and the immunoglobulins contents including secretory IgA (sIgA), IgA, IgG and IgM in the cecal tonsil induced by methionine deficiency were observed
It is well known that the cecal tonsil is the major lymphoid tissue in avian cecum which participates in the antibody production and is an important component in the mucosal immune system
B cells in the cecal tonsil can migrate into the lamina propria and develop into mature immunoglobulinproducing plasma cells (Fagarasan et al, 2011)

Summary

Introduction

Methionine is an essential amino acid which possesses high nutritional value and important physiological functions, such as cellular growth and the development of animal (Mirzaaghatabar et al, 2011; Yen et al, 2002), detoxification (Kim et al, 2006), antitumor or anticancer (Horvat et al, 2006; Li et al, 2009), resistance for coccidium infection (Rama Rao et al, 2003) and synthesis of protein (Brosnan, 2006; Tesseraud et al, 2011), etc. Methionine is closely related to the immune function of livestock and poultry, and is responsible for the regulation of cell function such as oxidation and reduction (Hoshi & Heinemann, 2010). Methionine deficiency has negative effects on immune organs including thymus, bursa of Fabricus, spleen (Wu et al, 2012a; Wu et al, 2012b; Wu et al, 2013) and small intestine (oxidative stress and apoptosis) (Li et al, 2018; Ruan et al, 2018; Wu et al, 2018a; Wu et al, 2018b). The objective of this study is to determine the effects of methionine deficiency on the B lymphocytes and immunoglobulins in the cecal tonsil of broiler chicken by methods including IHC, WB, qRT-PCR and ELISA. Few studies focus on the effects of methionine deficiency on the cecal tonsil in avian, so this research aims to investigate the role of methionine on the important intestinal immune organ – cecal tonsil

Objectives

Methods

Results

Conclusion