Effect Of Low Protein Diet On Fecal And Urine Characteristics And Fermentation Products Of Finishing Pigs

In the production of pigs,how to ensure the healthy production of pigs,while achieving environmental friendliness,resource conservation is now a technical problem that needs to be solved urgently.At present,the research on the application of low-protein diets in pig production mainly focuses on the performance of low-protein diets on pig production performance and nutrient digestibility,and the research on the physical and chemical properties of pig excreta and fermentation products is very much There is little,so exploring the contribution of low-protein diets to the end of pig production is also extremely valuable.the purpose of this study was to study the growth performance,nutrient digestibility,physicochemical characteristics of excretion,anaerobic fermentation products of excrement and microbial diversity of fattening pigs with low-protein diets combined with phytase and probiotics in the ideal amino acid mode.the impact will provide data support for the reduction of the source of low-protein diets in pigs and the subsequent treatment of manure,and promote the green,efficient and sustainable development of the pig breeding industry.A total of 72(du × long × large)ternary cross-breeding pigs with a weight of about65 kg were selected and randomly divided into 2 groups(test group and control group)with 6 pens per group and 6 pigs per pen They were fed a conventional diet(CP level was 15%),and the experimental group was fed a low-protein diet(CP was 12% +phytase + probiotics).The experimental diet is based on NRC(2012)and the ideal amino acid model.During the test,the production performance indicators,blood biochemical indicators,nutrient digestion and metabolic rate,physical and chemical properties of manure and fermentation broth,fermentation products and microorganisms were measured.the result shows:1.The impact of low-protein diets on fattening pig performance,nutrient digestion and nitrogen and phosphorus emission reduction.The fattening pigs were fed a low-protein amino acid balanced diet,and their production performance was not significantly different from the control group(P> 0.05);compared with the conventional protein diet group,the serum BUN concentration in the low-protein treatment group was significantly reduced(P <0.05),While other serum indicators have no significant effect;the metabolic rate of crude protein and the apparent digestibility of phosphorus(P <0.05)in the low protein treatment group were significantly higher than those in the conventional diet group,while protein,dry matter,organic matter,calcium,The apparent digestibility of crude fat has an increasing trend,but it is not significantly different from the conventional diet group;the nitrogen and phosphorus emissions of the low-protein diet group have decreased by 32.64% and27.13%,respectively.It can be seen that the dietary protein of fattening pigs is reduced from 15% to 12%,and its production performance has no significant effect,which improves the digestion and metabolism of nutrients,thereby reducing the emission of nitrogen and phosphorus and other nutrients from fattening pigs.2.Effect on the physical and chemical properties and fermentation products of fattening pig manure and urine fermentation broth(1).Low-protein diet can significantly reduce the concentration of TN,NH3-N,TOC and pH(P <0.01)in the fermentation manure of fattening pig manure and urine;but TP concentration and C / N are significant in the low-protein diet groupHigher than the conventional diet group(P <0.05);the COD concentration between the two groups was not significantly different(P> 0.05).(2).The pH value of the fermentation broth of the low-protein diet and the conventional diet group after anaerobic fermentation is lower than that before fermentation(P <0.01),while the concentrations of TN,NH3-N,COD,TOC,and TP are all more anaerobic Extremely increased before fermentation(P <0.01),where the components in the fermentation broth of the low-protein diet group were increased by27.8%,54.0%,43.9%,and 35.8%,respectively;the components of the fermentation broth in the conventional diet group were Increased by 71.7%,83.1%,38.4%,and40.5%;the C / N of the fermentation broth of the low-protein diet group was reduced by54.1%(P <0.01)compared with before fermentation;the C / N of the fermentation broth of the conventional diet group was It increased by 22.3% before fermentation(P <0.01).(3).Low-protein diet can significantly reduce the concentration of odorous compounds in the fermentation liquid of fattening pig manure and urine(P <0.05),and significantly reduce the concentration of ammonia gas produced by anaerobic fermentation of fattening pig manure and urine mixture(P <0.01).During anaerobic fermentation,the low-protein diet significantly reduced the concentration of hydrogen sulfide and acetic acid in the fermentation broth(P <0.01),and significantly increased the concentration of butyric acid and valeric acid in the fermentation broth(P <0.01).(4).Anaerobic fermentation can significantly increase the concentration of VFA in the fermentation broth of the conventional diet group and the low-protein diet group(P<0.01).The increase range of the VFA concentration in the two diet groups is between47% and 79%.Anaerobic fermentation can significantly reduce the concentration of indole in the fermentation broth of the conventional diet and low-protein diet groups(P<0.01),but it significantly increased the fermentation broth of the conventional diet and low-protein diet groups.The concentration of p-cresol and skatole in the medium(P<0.01).3.Microbial diversity analysis of fermentation broth The microbial diversity analysis of the fermentation broth of each fermentation time node shows that the dominant bacteria at the phylum level are Firmicutes and Bacteroidetes.At the genus level,the addition of 0.1% probiotics to the low-protein diet increased the abundance of Lactobacillus in the faeces of fattening pigs by 72.3%compared to the conventional diet group.The abundance of Bacteroides,Tissierella and Fastidiosipila in the diet group.The increase in their abundance is strongly correlated with the nutrient of the fermentation broth.In summary,a low-protein amino acid balanced diet can effectively reduce protein and phosphorus emissions by 32.64% and 27.13% without reducing the performance of fattening pigs.Reduce the content of TN,NH3-N and the concentration of odorous compounds in the excrement of fattening pigs,effectively inhibit the production of ammonia.Anaerobic fermentation of fattening pig excrement can effectively increase the abundance of the main species in the fermentation broth of low-protein diet group.