Effects Of Microbial Solid Fermentation Of Low Value Raw Materials And Low Nitrogen And Phosphorus Feed Compound Enzyme On Growing Pigs

The aim of this study is to explore the possibility of reducing the cost of growing pigs and reducing excretion under the current culture environment from two perspectives: solid-state fermentation and enzyme preparation.Experiment 1: microbial solid fermentation low value raw materials and its application in growing pigs.In this experiment,70% rapeseed meal,15% bran and 15% corn bran were selected as low value raw materials for solid-state fermentation.Effective strains were screened from lactic acid bacteria,yeast,Bacillus subtilis,Aspergillus Niger and neutral protease,and the optimal fermentation conditions were determined.The results were as follows: The best strain combination was yeast,lactic acid bacteria and neutral protease,the best fermentation condition was 55% water,fermented at 30?for 60 hours.Mixed fermentation could increase crude protein by 16.3%(P< 0.01),precipitated nitrogen by 332.0%(P<0.01),glucoside by 27.2%(P<0.01),phytic acid by 37.8%(P<0.01)and tannin by 21.5%(P<0.01).A total of 72 growing pigs(BW=39 kg)were randomly divided into three treatment groups.They were fed corn meal soybean basal diet(Con),15% unfermented low value raw material diet(RM)and 15% fermented feed diet(FRM)for 28 days,respectively.The results were as follows: the average daily gain of pigs fed Con,RM and FRM were 626,592 and 670 g/d respectively.The phosphorus digestibility and arginine digestibility of FRM fed pigs were significantly higher than those of RM fed pigs(P<0.05).The digestibility of tyrosine and phenylalanine digestibility of FRM fed pigs were higher than those of pigs fed with RM(P<0.1).The content of urea nitrogen in serum of RM growing pigs was significantly higher than that of pigs fed Con(P<0.05),while there was no significant difference in serum urea nitrogen between pigs fed FRM and Con.The contents of SOD and MDA in pig serum fed with FRM or Con were significantly lower than those in RM group(P<0.01).In summary,solid-state fermentation improves the nutritional value of mixed low value feed,which can replace soybean meal in some growing pigs diets.Experiment 2: effects of compound enzyme preparation with low nitrogen and phosphorus feed on growing pigs.In this experiment,96 growing pigs(BW=36kg)were randomly divided into four treatment groups,feeding basal diet,low phosphorus diet(adding compound enzyme),low nitrogen diet(adding compound enzyme)and low phosphorus and low nitrogen diet(adding compound enzyme)for 37 days feeding experiment.The results were as follows: there was no significant difference in performance between four groups of growing pigs.The phosphorus digestibility of pig in low phosphorus group and low phosphorus low nitrogen group was significantly higher than that in basal diet group and low nitrogen group(P<0.05).The blood calcium content in the serum of growing pigs in low phosphorus and low nitrogen group was significantly higher than that in basal diet group and low phosphorus group(P<0.05).The results showed that adding complex enzymes to low phosphorus and low nitrogen feed would not affect the health of growing pigs,and could improve the efficiency of phosphorus utilization and reduce phosphorus excretion in feces.Therefore,the two methods can reduce feed costs and reduce culture excretion without affecting the production performance and health status of growing pigs.