Immuno-pathological studies on broiler chicken experimentally infected with Escherichia coli and supplemented with neem (Azadirachta indica) leaf extract

Vikash Sharma,K K Jakhar,Swati Dahiya

doi:10.14202/vetworld.2016.735-741

Abstract

Aim:The present study was conducted to evaluate the effects of neem leaf extract (NLE) supplementation on immunological response and pathology of different lymphoid organs in experimentally Escherichia coli challenged broiler chickens.Materials and Methods:For this study, we procured 192-day-old broiler chicks from local hatchery and divided them into Groups A and Group B containing 96 birds each on the first day. Chicks of Group A were supplemented with 10% NLE in water, whereas chicks of Group B were not supplemented with NLE throughout the experiment. At 7th day of age, chicks of Group A were divided into A1 and A2 and Group B into B1 and B2 with 54 and 42 chicks, respectively, and chicks of Groups A1 and B1 were injected with E. coli O78 at 107 colony-forming units/0.5 ml intraperitoneally. Six chicks from each group were sacrificed at 0, 2, 4, 7, 14, 21, and 28 days post infection; blood was collected and thorough post-mortem examination was conducted. Tissue pieces of spleen and bursa of Fabricius were collected in 10% buffered formalin for histopathological examination. Serum was separated for immunological studies.Result:E. coli specific antibody titer was significantly higher in Group A1 in comparison to Group B1. Delayed-type hypersensitivity response against 2,4 dinirochlorobenzene (DNCB) antigen was significantly higher in Group A1 as compared to Group B1. Pathological studies revealed that E. coli infection caused depletion of lymphocytes in bursa of Fabricius and spleen. Severity of lesions in Group A1 was significantly lower in comparison to Group B1.Conclusion:10% NLE supplementation enhanced the humoral as well as cellular immune responses attributed to its immunomodulatory property in experimentally E. coli infected broiler chicken.

Highlights

Avian colibacillosis is one of the important bacterial diseases of poultry caused by Escherichia coli, producing considerable morbidity and mortality and associated with heavy economic losses to the poultry industry and is an association with various disease conditions as a primary pathogen or secondary pathogen [1]
Chicks of Group A were supplemented with 10% neem leaf extract (NLE) in water, whereas chicks of Group B were not supplemented with NLE throughout the experiment
At 7th day of age, chicks of Group A were divided into A1 and A2 and Group B into B1 and B2 with 54 and 42 chicks, respectively, and chicks of Groups A1 and B1 were injected with E. coli O78 at 107 colony-forming units/0.5 ml intraperitoneally

Summary

Introduction

Avian colibacillosis is one of the important bacterial diseases of poultry caused by Escherichia coli, producing considerable morbidity and mortality and associated with heavy economic losses to the poultry industry and is an association with various disease conditions as a primary pathogen or secondary pathogen [1]. E. coli is a commensal organism of the intestinal tract of poultry but under certain adverse conditions such as poor ventilation, overcrowding, and immunosuppression, it turns pathogenic [2]. Frequent association of E. coli with various immunosuppressive diseases like Gumboro disease and in young birds, in which immune system is not fully developed has been found. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

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