Study On The Quality And In Vitro Degradation Characteristics Of Potato Pulp And Two Kinds Of Straw Mixed Silage

With the rapid development of China’s animal husbandry,people’s consumption of animal food has also increased year by year,and the problem of “human and animal competition for food”has become more and more serious.Northeast China has a vast territory and developed agriculture and animal husbandry.In the process of agricultural production,a large number of by-products such as crop stalks and dregs will be produced.These by-products can be used as feed to alleviate the problem of roughage shortage.Potato pulp and crop straw are an important part of the agricultural by-products in Northeast China,but the high moisture content of potato pulp is not easy to store,the high fiber and low digestibility of the straw restrict their utilization.Therefore,it is very important to develop the feed technology of potato pulp and straw.This research aims to study the nutritional value,fermentation quality,bacterial diversity,and in vitro degradation characteristics of mixed silage with different ratios of potato pulp,rice straw or corn straw by adding lactic acid bacteria and fibrolytic enzyme.Experiment 1: Study on fermentation quality of the mixed silage of potato pulp with rice straw or corn strawThe experiment adopts a two-factor experimental design of 2×3(2 different raw materials×3ratios),under the fresh weight,the corn straw,rice straw,and potato pulps are divided into 6treatments,(1)35% corn straw: 65% potato pulp(65% PC),(2)30% corn straw: 70% potato pulps(70%PC),(3)25% corn straw: 75% potato pulp(75% PC);(4)35% rice straw: 65% potato pulp(65% PR),(5)30% rice straw: 70% Potato pulp(70%PR),(6)25% rice straw: 75% potato pulp(75%PR).The lactic acid content of 75% PR was significantly higher than that of the 75% PC treatment group(P < 0.0001).The ammonia nitrogen/total nitrogen of PC Significantly high er than PR(P < 0.0001).The content of lactic acid bacteria in 75% PR was significantly higher than that in the 75% PC treatment group(P = 0.0022).the total volatile fatty acid(VFA)content of the 75%potato pulp treatment group was significantly higher than the other two treatment groups(P <0.05),and the ammonia nitrogen concentration of PR was significantly higher than PC(P <0.0001).Experiment 2: Biological characteristics and stress resistance of Lactobacillus plantarum,Lactobacillus brucei,Lactobacillus rhamnosus,and Lactobacillus complexCombine Lactobacillus plantarum(CGMCC10516),Lactobacillus brucei(BNCC189797),Lactobacillus rhamnosus(ATCC53013)and select 9 compound ratios.Use the number of viable bacteria and the p H after 12 h as indicators to screen out the optimal ratio.Compare the biological characteristics and stress resistance of the optimal ratio of compound lactic acid bacteria and single lactic acid bacteria.Lactobacillus plantarum,Lactobacillus brucei and Lactobacillus rhamnosus with a ratio of 3:3:2 composite lactic acid bacteria have the largest number of viable bacteria and the lowest p H after 12 hours.The p H of lactic acid bacteria and Lactobacillus brucei was the lowest when activated for 24 h,and the acid resistance,bile salt tolerance and bacteriostasis of compound lactic acid bacteria were higher than that of single lactic acid bacteria.Experiment 3: The effects of lactic acid bacteria and fibrolytic enzyme on the fermentation quality,bacterial diversity,aerobic stability,and in vitro degradation of the mixed silage of potato pulp with rice straw or corn strawThe optimal ratio of mixed silage(75%PR)screened out in experiment 1 is subjected to four treatments:(1)No additives(control treatment);(2)lactic acid bacteria(LAB,Lactobacillus plantarum(CGMCC10516),Lactobacillus brucei(BNCC189797),Lactobacillus rhamnosus(ATCC53013),add in a ratio of 3:3:2);(3)fibrolytic enzyme(EN);(4)LAB + EN.LAB+EN had the lowest NDF content(P = 0.0006),and the ADF of EN and LAB+EN treatment groups was significantly lower than other treatment groups(P = 0.0022).WSC in the treatment group with EN and LAB+EN was significantly higher than that in the control and LAB groups(P < 0.0001).The lactic acid content of the LAB and LAB+EN groups were significantly higher than that of the control and EN groups(P = 0.0058).The lactic acid bacteria of the LAB and LAB+EN groups were higher than those of the control and EN groups,and Acinetobacter was lower than the control and EN groups.During aerobic exposure,the number of yeasts and molds in the mixed silage of LAB and LAB + EN groups was less,and there was a longer aerobic stable period.The NDF degradation rate of LAB+EN group in mixed silage was significantly higher than other treatment groups(P < 0.0001).In summary this study,the following conclusions:(1)The optimal combination of potato pulp and two kinds of straw mixed silage is 75% potato pulb and 25% rice straw mixed silage.(2)Lactobacillus plantarum,Lactobacillus buchneri,and Lactobacillus rhamnosus with a ratio of 3:3:2 composite lactic acid bacteria have a good grow th curve,acid production rate,and stress resistance.(3)75% potato pulp and 25% rice straw mixed silage added compound lactic acid bacteria and fibrolytic enzyme,the LAB + EN treatment group has the best fermentation quality,aerobic stability and in vitro degradation rate.