Polysaccharide from Walnut Green Husk alleviates ochratoxin a-induced anorexia in chicks via m6A-mediated FXR regulation of orexigenic genes

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Ochratoxin A ( OTA ) is a common mycotoxin in poultry feed that impairs feed intake and growth performance, leading to substantial economic losses. Walnut green husk polysaccharides ( WGP ) have previously been reported to alleviate OTA-induced hepatic and intestinal damage, but their effects on anorexia and underlying mechanisms remain unclear. This study investigated whether WGP mitigates OTA-induced anorexia in broilers and explored its molecular basis. One-day-old broilers were fed OTA diets with or without WGP supplementation for three weeks. WGP significantly improved feed intake and body weight, attenuated hypothalamic inflammation, and restored the mRNA expression of orexigenic neuropeptides ( AGRP, NPY ). 16S rRNA sequencing and serum metabolomics revealed that WGP reshaped gut microbial composition and bile acid ( BA ) profiles, increasing the abundance of Lactobacillus and Bifidobacterium and restoring CA and DCA levels. WGP also reversed OTA-induced reductions in FXR protein expression despite unchanged FXR mRNA levels, suggesting post-transcriptional regulation. Consistently, OTA increased global m⁶A methylation and upregulated METTL3 and YTHDF2 expression, which were significantly attenuated by WGP. SELECT-qPCR further confirmed that m⁶A enrichment at a specific site in FXR mRNA was elevated by OTA but reversed by WGP. These findings indicate that WGP alleviates OTA-induced anorexia via the gut microbiota-BA-FXR-m⁶A-neuropeptide axis, revealing a novel epigenetic mechanism in appetite regulation and highlighting WGP as a promising dietary strategy to mitigate mycotoxin-induced anorexia in poultry production. Feeding behavior directly affects productivity and economic efficiency. Feed intake suppression reduces feed utilization efficiency and increases production costs. Ochratoxin A ( OTA ), a common mycotoxin found in feed, has been reported to impair feed intake, hinder growth, and increase mortality in poultry, posing a serious threat to the poultry industry ( Malir, et al., 2016 ). Feeding behavior in poultry is regulated by the coordinated actions of multiple organs, among which the hypothalamus serves as a central regulatory hub. The arcuate nucleus ( ARC ) in the hypothalamus is crucial for processing metabolic cues from the body, such as hormonal and nutritional signals, to finely control food intake and energy balance ( Ding, et al., 2021 ). The ARC contains two functionally antagonistic populations of neurons: one produces appetite-stimulating neuropeptides, NPY and AGRP, while the other secretes POMC, a neuropeptide that suppresses hunger and reduces food consumption ( Morton, et al., 2006 ). However, the underlying mechanisms by which OTA induces feed intake suppression remain largely unclear and warrant further investigation.

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