Role of Monochromatic Light on Development of Cecal Tonsil in Young Broilers

Abstract

Previously, the different monochromatic lights have been demonstrated to affect splenocyte proliferation and melatonin (MEL) secretion in broilers. The present study was designed to evaluate the effects of different monochromatic lights on the development and immune function of broiler cecal tonsils, and to disclose the mechanisms underlying these phenomena. A total of 185 broilers (P0) including intact, sham-operated, and pinealectomized groups were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by a light-emitting diode system for 14 days. Compared with RL groups, the GL in the intact and sham-operated groups showed larger follicle areas (66.70%), higher percentages of proliferating cell nuclear antigen (PCNA)-positive cells (33.33%), increased numbers of IgA 1 cells (48.60%), and increased antioxidase activity (33.33%-61.37%), whereas, the density of iNOS and MDA content in GL were lower (43.63%-54.43%) than that of RL. In contrast, after pinealectomy, the area of follicles, the percentage of PCNA-positive cells, the number of IgA 1 cells, and the antioxidase activity decreased in the different light treatments, but the density of iNOS and MDA content increased substantially. There was no significant difference in these parameters between broilers exposed to GL and other lights (P 5 0.085-1.000). The results suggested that the enhanced effects of GL on the development and immune function of cecal tonsils in young broilers were mediated by elevated antioxidative status via up-regulation of MEL. Anat Rec, 297:1331Rec, 297: -1337

Influence of Different Light Spectra on Melatonin Synthesis by the Pineal Gland and Influence on the Immune System in Chickens

“…In an earlier study, Xie et al [215] reported that green light and blue light improved gut mucosal immunity in broiler chickens, and they revealed that the population of iIEL and IgA + cells became evident in the group subjected to green light treatment at an early growth stage (7-21 days) and blue light treatment at a later growth stage (49 days) [215] (Figure 3). These results agree with those obtained by Li et al [78], namely that green light had a positive influence on IgA + cell counts at 14 days of age in the cecal tonsil of chickens. However, the growth induced by light treatment disappeared after pinealectomy, a finding that suggests that melatonin secreted by the pineal gland under the influence of green light is essential for the improvement of immune function [78].…”

“…These results agree with those obtained by Li et al [78], namely that green light had a positive influence on IgA + cell counts at 14 days of age in the cecal tonsil of chickens. However, the growth induced by light treatment disappeared after pinealectomy, a finding that suggests that melatonin secreted by the pineal gland under the influence of green light is essential for the improvement of immune function [78]. These results agree with those obtained by Li et al [78], namely that green light had a positive influence on IgA + cell counts at 14 days of age in the cecal tonsil of chickens.…”

“…Some studies have reported an increased immune function of the thymus through an increased organ index and IL-2 concentration [136,204] following the exposure of chickens to monochromatic green light (560 nm). These results confirm previous studies showing that green light enhanced B lymphocyte proliferation in the spleen [125,163] and small intestine [78,205].…”

Light regimen on health and growth of broilers: an update review

“…Interestingly, replacing white light with blue light have been reported to modify the activities of heat shock biomarkers, and confer higher resistance to heat stress on broilers ( Abdo et al, 2017 ). These beneficial effects might be attributable to the enhanced expression of clock genes in the pineal gland and upregulation of melatonin synthesis induced by green or blue lighting, therefore contributing to improve antioxidant capacity and immune function of broilers ( Ke et al, 2011 ; Li et al, 2014 ; Jiang et al, 2016 ).…”

Impact of Housing Environment on the Immune System in Chickens: A Review

“…However, recent studies showed that UV light lowers the H/L ratio in laying hens [135] and broilers [136]. The number of intraepithelial lymphocytes and IgA+ cells in cecal tonsils and in the small intestine were shown to be higher under green and blue light compared to red light [137,138]. Studies investigating the functionality of immune cells emerge with a clearer picture.…”