| Fumonisin B1 is the most common foodborne mycotoxin produced by Fusarium moniliforme Sheld and is widely present in cereal crops and by-products around the world.FB1affects the appetite of growing pigs and inhibits animal growth and development,and FB1 is neurotoxic,immunotoxic,cytotoxic and organotoxic.Due to its heat stability,it is easily taken into the body through the food chain,causing great harm to human health and livestock farming.Compared with other farmed livestock,pigs,as monogastric animals,lack microorganisms in the gastrointestinal tract that can break down mycotoxins,and because corn is an important raw material in pig feed,pigs are more sensitive than other livestock to the intake of FB1 from feed.Despite the efforts made by previous generations,food safety problems induced by mycotoxins are still inevitable so far.Therefore,efficient and safe detoxification methods have attracted wide attention from farming enterprises and veterinary experts.Most physical and chemical detoxification methods tend to destroy the nutrient content of feed and change the palatability,thus affecting the quality and yield of animal products.Biological detoxification methods,which use living microorganisms or biological enzymes to convert mycotoxins into low-or non-toxic degradation products,are widely favored for their high degradation efficiency and relative safety.Currently,enzymatic digestion is an ideal detoxification method that has attracted widespread attention.Under laboratory conditions,the carboxylesterase Fum DSB has a high degradation rate of FB1,as well as excellent acid-base and thermal stability,but its role in vivo is unknown.Brain-gut regulation plays an important role in appetite control.In the central nervous system,the hypothalamus is the key area involved in appetite regulation,and the appetite regulation network radiated from it is also a coordinated and mutually influential regulation network.The intestine is the largest endocrine organ of the body,capable of secreting various types of regulatory peptide hormones,which have important appetite regulating effects.Neural and hormonal signaling molecules from the intestine provide hunger and satiety signals to the hypothalamus through their specific receptors.The aim of this study was to investigate the functional characteristics of FB1 detoxification enzyme carboxylesterase Fum DSB in growing pigs from the perspective of brain-gut regulation.Twenty-four 2-month-old healthy ternary crossbred pigs（Duroc×Long White×Large White）were randomly divided into blank control group,FB1 group and Fum DSB group according to the same male to female ratio according to the initial body weight.The control group was fed the basal diet,the conventional maize meal in the FB1 group diet was replaced by the FB1-treated toxic maize meal in the test group diet,and the final level of FB1 in the diet was 5 mg/kg,and the Fum DSB group was supplemented with 0.1%Fum DSB on to the FB1group diet.the feeding trial was conducted for a total of 42 d,including a pre-feeding period of7 d.After 35 days of animal testing,hypothalamus and jejunum samples were collected from the test animals.The samples of hypothalamus and jejunum were analyzed by HE staining,Western-Blot,q RT-PCR and immunohistochemistry.The test results showed that:（1）The results of animal feeding test showed that no clinical signs of toxicity such as diarrhea,abdominal pain and even death occurred in growing pigs after ingestion of 5 mg/kg FB1,but their feed intake and average daily weight gain were significantly decreased（P<0.05）,and feed intake and average daily weight gain were significantly increased in the Fum DSB group compared with the FB1 group（P<0.05）.（2）Histomorphological results showed that some pathological changes such as vacuolization of neuronal cells in hypothalamus,fragmentation and detachment of jejunal villous epithelium,reduction in the number of cupped cells and infiltration of inflammatory cells in jejunum were observed in growing pigs after the intake of FB1.The pathological changes in Fum DSB group were weaker.（3）The results of molecular tests showed that the levels of inflammatory cytokines（IL-2,IL-6,IL-8,TNF-α,IFN-γ）were elevated in the hypothalamus and jejunum of the FB1 group,and the secretion of appetite-related brain and intestinal peptides and receptors（Ghrelin,Obestatin,NPY,PYY,POMC）was disturbed.These phenomena were Effectively avoided in the Fum DSB group compared with the FB1 group.In summary,the ingestion of FB1 in growing pigs can disrupt the hypothalamus and jejunal tissue structure,cause changes in the expression and distribution of inflammatory factors,and can suppress their appetite by inhibiting pro-feeding factors,while the negative Effects induced by FB1 were reduced and the inflammatory response was suppressed by the addition of Fum DSB as a degrading mycolytic enzyme in the feed. |
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