| Odor pollution in laying hens are one of the important problems of sustainable development.Ammonia?NH3?and hydrogen sulfide?H2S?is the main odor in laying hens a.According to the report,varieties of different layers have different potential of NH3 and H2S emission.Therefore,this paper adopts the cecum content in vitro fermentation for selecting low odor emission varieties of laying hens,and through the respiratory metabolism box method and 16Sr DNA,quantitative PCR,metabonomics technology,searching the mechanism of low NH3 and H2S emission in layeing hens,It mightprovid atheoretical basis for looking for effective odor emission reduction method.This studyinclude two parts.Experiment 1 choiceHyline,Roman powder,Nongda 7,xinghua chicken,silkie,Jingfen laying hen,and adopts the cecum content in vitro fermentation,seting seven treatment?1 blank,6 varieties of laying hens?,5repeats each treatment,detection of NH3 and H2S and other related indicators,to filter the low odor emission of laying hens varieties;Experiment 2 chioce Roman powder laying hens,Nongda no 7 as the control group,12 sets of respiration chamber,21 days of the trial period,including feeding period of 14 days in advance,cover the seal cover adaptation after 4 days and gas extraction monitoringfor three days.The main result are as follow:?1?After 12h in vitro fermentation,Roman powder production of laying hens appendix output volume are 25.87±1.39 mL,NH3 and H2S emission were0.08±0.001mg?0.06±0.001mg.Roman powder discharge of total volume and NH3 layers are significantly lower than other varieties of five layers?P<0.05?,discharge of H2S was significantly lower than nongda no 7,Hyline,silkie,Jingfen 1?P<0.05?.?2?respiration chamber Experiment showed that Roman powder laying hens'emissions of NH3 and H2S were 1.66±0.28 mg/g,0.31±0.05 mg/g,significantly lower than nongda 7?P<0.05?.Compared with nongda 7,Roman powder layers of NH3 and H2S emission reduction potential of 11.7%and 31.7%respectively.?3?Roman powder laying hens laying rate is significantly higher than nongda no 7?P<0.05?.The cecum p H,uric acid,urea,urease activity,urease bacteria,sulfate reducing bacteria of Roman powder laying hens were significantly lower than the number of nongda no.7?P<0.05?,total volatile fatty acid,SO42-was significantly higher than that of nongda no7?P<0.05?.16SrDNA results show that the Proteobacteria,Fusobacterium,Desulfovibrio,Sutterella of theRoman powder laying hens was significantly lower than nongda 7?P<0.05?,Roman powder laying hens of the genus Lactobacillus relative abundance than Nongda 7?P<0.05?.?4?The OPLS-DA model is established and identified the difference significant metabolites,a total of 142 metabolites is different between two varieties.Combined with metabolic pathways track,the results indicatethe varieties changexanthine metabolic pathways in the intestines including adenine and GMP break up into xanthine through oxidative deamination synthesis pathways and L-glutamine metabolic pathways of deamidation generated L-glutamic acid pathwayin Nongda 7is significantly higher than Roman powder laying hens.The cysteine metabolic pathways in Nongda 7 intestines of O-acetylcysteine combined with H2S generates cysteine is lower than the Roman powder laying hens,and patheway of cysteine break down into Pyruvate results H2S increasing.In summary,the Roman powder layers for this test under the condition of low odor varieties of laying hens.Compared with nongda 7,it is possible emission reduction mechanism is by changing the cecum microbial community which produces H2S and NH3,and themicrobial adjustingpH,uric acid,uric acid levels and corresponding enzymes in cecum.The varieties influence the cecum urea decomposition and L-glutamine,yellow purine metabolism and cysteine metabolic pathways,thereby reducing NH3 and H2S emission. |
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