Study On Effect Of Candida Krusei On Chicken Manure Deodorization?Growth Performance Of Broilers And Ammonia-reducing Pathway

Odor gases emission has been an important part of livestock pollution,can directly harm to animals and human health.This paper is consist of three experiments.Firstly,take the breakthrough point of controlling the emission of NH₃ and H₂S from chicken manure,spray sorted Candida Krusei?LSA?which has the ability of ammonia-nitrogen removal into chicken manure to validate its inhibiting effect of odor.Secondly,through the feeding application research,to validate LSA's effect on broiler's growth performance,providing an research basis to further development of creating biological deodorization feed additive.Lastly,analyzing the metabolic product in the process of LSA's metabolizing of ammonia nitrogen,to explore its metabolic pathways,provide theory basis for the revealing of ammonia nitrogen degradation mechanism,and provide reference for industrial application of biological denitrification.Experiment 1:The effect to chicken manure's NH₃,H₂S,pH and Temperature after adding LSA to chicken manure was studied in vitro.The trial group added LSA according to 10%of the quantity and evenly sprayed on the surface of fresh chicken manure,then mixed well.The control group added with equivalent distilled water.Every 1 h test the content of NH₃,H₂S and the pH and T of chicken manure.The result shows that compared with the control group,there is a remarkable inhibition effect on NH₃and H₂S after adding LSA to chicken manure.Within 24 h after inoculation gained the best inhibition effect on NH₃,with the rate of 63.64%.While the best time of inhibition effect on H₂S was within 20 h,with the rate of 40.48%,then began to decline.At the mean time,the pH and T of the chicken manure in the fermentation process experienced rising and declining,and the change was relatively stable.Thus,spraying LSA on the chicken manure can effectively inhibit the release of odor gases such as NH₃ and H₂S,showing the effective function of deodorization.Experiment 2:A total of 240 1-day-old healthy Arbor Acres male broilers were randomly allotted to 4 groups with 6 replicates per group and 10 birds per replicate.The four diets included a basal diet without antibiotic and 3 experimental diets supplemented with Candida Krusei LSA of 1×10⁷ CFU/kg,1×10⁸ CFU/kg and 1×10⁹ CFU/kg,respectively,based on the basal diet.Broilers were slaughtered at 42days old.The results showed as follows:?1?the difference of ADFI,ADG,BW and F/G of each experiment group was not significant?P>0.05?.?2?Candida Krusei LSA supplemented in diets was no significant influence on thymus index and bursal index of each experiment group?P>0.05?,but LSA of1×10⁸ CFU/kg significantly increased spleen index?P<0.05?.?3?Candida Krusei LSA supplemented in diets significantly reduced the uric acid and ammonia level in blood?P<0.05?,but it has no significant influence on biochemical indices such as serum total protein,albumin and globulin?P>0.05?.?4?Candida Krusei LSA supplemented in diets was no significant influence on water content and total nitrogen of manure?P>0.05?,but LSA of 1×10⁸ CFU/kg decreased the ammonia nitrogen content of manure significantly?P<0.05?.In conclusion,Candida Krusei LSA supplemented in diets has no adverse effect on growth performance,immune organs and blood biochemical indices;Candida Krusei LSA supplemented in diets can enhance the immune function of broilers,improve their nitrogen metabolism,decrease the ammonia nitrogen content in the manure,and reduce environmental pollution.Experiment 3:Under aerobic conditions,use NH₄⁺-N and its intermediate metabolic products as the only nitrogen source,by testing the change of the concentration of NH₄⁺-N,NH₂OH-N,NO₃^--N,and NO₂^--N to explore the LSA's possible metabolic pathways in the process of ammonia reduction.The results showed that:?1?LSA can use ammonia nitrogen,hydroxylamine nitrogen,nitrate nitrogen and nitrite nitrogen to grow and breed.?2?When strains LSA used NH₄⁺-N as the only metabolic nitrogen source,the concentration of NH₄⁺-N declined from the initiative of 344.07 mg/L to 76.03 mg/L,removed the amount of 268.04 mg/L,the total removal rate reached 77.90%.At the same time to generate the intermediate NH₂OH-N,NO₃^--N and NO₂^--N,indicating that LSA has the ability of heterotrophic nitrification.The pH of medium changed significantly in reaction process,inferring that there was acid production during the process of metabolism.?3?When using NH₂OH-N as the only metabolic nitrogen source,strain LSA can not only use the only nitrogen source to grow,but also can degrade it.During the whole process,there was only a small amount of intermediate NO₃^--N and NO₂^--N accumulated and without transforming.?4?When using NO₃^--N or NO₂^--N as the only metabolic nitrogen source,there was only a small amount of nitrate nitrogen and nitrite nitrogen degraded,inferring that the degradation of nitrate was used for bacteria assimilation,and converted into nitrogen gas without aerobic denitrification.Therefore,there may be a new way of denitrification for LSA,namely:NH₄⁺-N—NH₂OH-N—N₂O—N₂.