Effects Of 6-MBOA On The Feeding,Digestion And Gut Microbiota Of Male Brandt's Vole(Lasiopodomys Brandtii)

6-MBOA is a plant secondary metabolite of oxime acids,which is mainly distributed in the seedlings or young tissues of Gramineae plants.6-MBOA is a chemical of antibacteria and allelopathy,and it can affect the reproduction of herbivorous mammals and inhibit the digestion and feeding of insects.However,the effects of 6-MBOA on feeding and digestion of herbivorous mammals have not been studied so far.Our previous study found that 6-MBOA is present in the seedlings of Leymus chinensis,a favorable plant of the Brandt's voles(Lasiopodomys brandtii).Therefore,Brandt's vole is the ideal animal to explore the effects of 6-MBOA on feeding and digestion of herbivorous mammals.In this study,adult male Brandt' s voles in 90 days age were chosen as the object of this research and three experiments were designed as the followings:(1)The feeding behavior were observed after supplying foods with different concentrations of 6-MBOA(O?g/g,50?g/g and 100?g/g as control food,low 6-MBOA dose and high 6-MBOA dose of food,respectively),and the duration of feeding,the feeding times and the food intake by Brandt's vole within 1 hour were counted;(2)Three doses of 6-MBOA(O?g/day,50?g/day and100?g/day as the control dose,low 6-MBOA dose and high 6-MBOA dose,respectively)were administered intragastrically to male Brandt's voles for different periods(1 day,7 days and 15 days),and the body weight variation,food intake,feeding-related hormones levels,the experession of feeding-realted genes in the hypothalamus,fecal nitrogen content and cecal microbiota in the male Brandt's voles were checked;(3)Collected the small intestinal contents of Brandt's voles and extracted the crude enzyme solution from them.Then,trypsin activity was measured after adding different concentrations of 6-MBOA(0,0.5mg/ml and 1mg/ml)into the crude enzyme solution.Our research was aim to explore the effect of 6-MBOA on the feeding and digestion of Brandt's voles and fully understand the effect of 6-MBOA on the herbivorous mammals,and supply the theoretical basis for the application of 6-MBOA in the animal husbandry.The results were as the followings:1.In the feeding behavior experiment,the duration of feeding,the feeding times and the food intake by male Brandt's voles for low and high 6-MBOA dose food within 1 hour were significantly lower than that for the control food.2.After 1 day of intragastric administration,the relative food intake of male Brandt's voles decreased significantly in both the low and high 6-MBOA dose groups.The contents of serum PYY and PP were significantly increased in both low and high 6-MBOA dose groups,and the serum content of ghrelin was significantly decreased in both low and high 6-MBOA dose groups.The mRNA expression levels of NPY and GSHR in the hypothalamus were significantly down-regulated in both low and high 6-MBOA dose groups,while the expression levels of POMC mRNA were significantly up-regulated in high 6-MBOA dose group.In the cecum of male Brandt's voles,6-MBOA increased the relative abundance of phylum of Deferribacteres,order of Deferribacterales,genus of Mucispirillum and species of Mucispirillum schaedleri,while family of Desulfovibrionaceae decreased significantly.After 7 days of intragastric administration,the relative food intake of Brandt's voles decreased significantly,while the fecal nitrogen content increased significantly in both low and high 6-MBOA dose groups.The serum PYY content was significantly increased but ghrelin content was significantly reduced in both low and high 6-MBOA dose groups.MCH mRNA expression in the hypothalamus was significantly down-regulated in high 6-MBOA dose group,and Y1 and GSHR mRNA expression was significantly down-regulated in both low and high 6-MBOA dose groups.The relative abundance of family of Lachnospiraceae in cecum decreased significantly,but the alpha diversity index did not change significantly.After 15 days of intragastric administration,6-MBOA had no significant effect on feeding and digestion of Brandt's voles.However,the relative abundance of some bacteria in cecum varied significantly,6-MBOA increased the relative abundance of phylum of Proteobacteria and Tenericutes,class of Deltaproteobacteria,Negativicutes,and Mollicutes,order of Lactobacillales and Spirochaetales,family of Ruminococcaceae,Spirochaetaceae,and Veillonellaceae,and genus of Desulfovibrio,while genus of Anaerostipes,species of Firmicutes bacterium ASF500,phylum of Bacteroidetes,class of Bacteroidia,order of Bacteroidales,family of Muribaculaceae and Prevotellaceae and genus of Bacteroides decreased significantly.The alpha diversity index Chaol and ACE were significantly higher in the low 6-MBOA dose group than the control group.3.The activity of trypsin decreased significantly after adding low and high concentration of 6-MBOA to the crude enzyme solution of small intestine.In summary,our study showed that the some dose of 6-MBOA addition in the diet could reduce the feeding time,times and amount of male Brandt's voles.Short-term intake of 6-MBOA could affect the levels of serum appetite-related hormones and the expression of feeding-related genes in the hypothalamus,thus inhibit the feeding of the male Brandt's voles.6-MBOA could inhibit the activity of trypsin,thus affect the digestion of protein in male Brandt's voles.Long-term intake of 6-MBOA could affect the composition and the alpha diversity index of cecum microbiota of male Brandt's voles.The inhibition of 6-MBOA on the feeding and digestion in male Brandt's voles was time dependent.Our study hinted that male Brandt's voles possess the capacity to adapt to the 6-MBOA and the gut microbiota could be a mechanism of male Brandt's voles in adaption to 6-MBOA.Totally,our study confirmed that 6-MBOA can affect the feeding and digestion of herbivorous mammals,which indicated that 6-MBOA might take part in the dynamic denfense in some plants to herbivore.Our research was conducive to a comprehensive understanding of the effects of 6-MBOA in the interaction between animals and plants.