Betaine was found to alleviate inflammation in different studies. Here, newly hatched broilers were randomly divided into control and betaine consumptive groups, who had access to normal drinking water and water with betaine at a dose of 1000 mg/L, respectively. At the age of two weeks, the boilers were intraperitoneally treated with LPS. The protective effects of betaine against LPS-induced skeletal muscle inflammation were studied. Betaine attenuated the LPS-induced overexpression of IL-6 significantly in the leg muscle. Furthermore, LPS lowered the expression of TLR4 and TLR2 but increased the expression of MyD88. Betaine eliminated the effect of LPS on the expression of TLR4 but not TLR2 and MyD88. LPS also increased the expression of Tet methylcytosine dioxygenase 2 (Tet2), and this effect was also eliminated by betaine consumption. MeDIP-qPCR analysis showed that the methylation level in the promoter region of IL-6 was decreased by LPS treatment, whilst betaine cannot prevent this effect. On the contrary, LPS significantly increase the methylation level in the promoter region of TLR4, which was decreased by the consumption of betaine. Our findings suggest that betaine can alleviate LPS-induced muscle inflammation in chicken, and the regulation of aberrant DNA methylation might be a possible mechanism.

Infectious bursal disease (IBD) significantly affects the poultry industry, causing substantial economic losses. This study aimed to investigate the effects of ghrelin on chicks infected with an attenuated virus strain of IBDV (aIBDV). Chicks were divided into 3 groups: a control group (group I), an aIBDV infection group (group II), and a ghrelin + aIBDV infection group (group III). Mice in groups II and III were fed until they reached 19 d of age and then inoculated with aIBDV to establish a subclinical infection model. Group III received an intraperitoneal injection of 0.5 nmol/100 g ghrelin from d 17 to 23. The present study utilized paraffin sectioning, H&E staining, and immunohistochemical staining to examine the effects of ghrelin on the bursa of fabricius and cecum tonsils in aIBDV-infected chicks. The results indicated that at 3 d postinfection (dpi), the average body weight of group III was significantly greater than that of group II (P < 0.05). At 3 and 7 dpi, the proportion of large lymphoid follicles in the bursa of fabricius in group III was notably greater than that in group II (P < 0.05). aIBDV infection resulted in bleeding, edema, and fibrosis in the cecal mucosal layer of chicks, but ghrelin administration mitigated these pathological changes. At 3 and 7 dpi, the thickness of the lamina propria in the cecal tonsils of group III was significantly lower than that in the cecal tonsils of group II (P < 0.05). Additionally, the percentage of large lymphoid follicles in the cecal tonsils of group III was significantly greater than that in group II at 3 and 5 dpi (P < 0.05). There were significantly fewer macrophages in the cecal tonsils of group III than in those of group II at 1, 3, and 5 dpi (P < 0.05). In conclusion, ghrelin supplementation improved performance and mitigated bursal atrophy in aIBDV-infected chicks. It also reduced histological lesions and immune responses in the cecum tonsil. Notably, the reduction in macrophages in the cecum tonsil following ghrelin administration may decrease the risk of aIBDV spread.

The aim of this study was to investigate the regulatory roles of distinct signaling cascades within the death receptor pathway in host cell apoptosis induced by Eimeria tenella (E. tenella); to this end, primary chicken embryo cecal epithelial cell culture, gene silencing, enzyme-linked immunosorbent assay (ELISA), Hoechst–Annexin V/PI apoptosis staining, hematoxylin–eosin (HE) staining, and quantitative real-time polymerase chain reaction (qRT-PCR) were employed. At 4, 24, 72, and 120 h post-inoculation (hpi) with E. tenella sporozoites, the proportion of apoptosis in six treatment groups [Group C, Group T0 (E. tenella infection group), Group T1 (E. tenella + Fas SiRNA), Group T2 (E. tenella + TRAIL SiRNA), Group T3 (E. tenella + TNFR1 SiRNA), and Group T4 (E. tenella + NC SiRNA)] and the dynamic changes in Fas cell surface death receptor (Fas), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), tumor necrosis factor receptor 1 (TNFR1), TNF receptor-associated death domain (TRADD), Fas-associated death domain (FADD), and death domain-associated protein (Daxx) expression and caspase-8 activity in the cells were determined. The results demonstrated that, from 4 to 120 hpi, the Fas and TNFR1 mRNA expression levels in Group T0’s host cells were significantly higher than those in Group C (p < 0.05 or p < 0.01). At 72 and 120 hpi, TRAIL mRNA expression in Group T0’s host cells was significantly or highly significantly elevated compared to that in Group C (p < 0.05 or p < 0.01). From 24 to 120 hpi, the expression levels of the FADD and Daxx genes, caspase-8 activity, and apoptotic rates in Group T1’s host cells were significantly lower than those in Group T4 (p < 0.05). At 72 and 120 hpi, the FADD expression, caspase-8 activity, and apoptotic rates in Group T2’s host cells were significantly reduced relative to Group T4 (p < 0.05). Additionally, at 4 hpi, TRADD gene expression in Group T3’s host cells was significantly lower than that in Group T4 (p < 0.05), while the apoptotic rate was significantly higher (p < 0.05). However, from 24 to 120 hpi, the TRADD expression, caspase-8 activity, and apoptotic rates in Group T3’s host cells were significantly lower than those in Group T4 (p < 0.05). The results indicated that, in the early stages of E. tenella development, TNFR1 overexpression promoted TRADD mRNA expression, thereby inhibiting the apoptosis of E. tenella host cells. In the middle and late developmental stages of E. tenella, the Fas-FADD, Fas-Daxx, TRAIL-FADD, and TNFR1-TRADD apoptotic pathways were all activated, collectively facilitating host cell apoptosis. The pro-apoptotic effects of these pathways were ranked in descending order, as follows: Fas signaling pathway > TNFR1 signaling pathway > TRAIL signaling pathway.