| With the development of people’s living standards,the demand for animal products gradually increased,resulted in the rapid increase of grains for the livestock.The struggling for food between livestock and humans become popular.The unconventional feed such as straw,brewery residue,and agricultural by-products etc.can be used as feed for ruminants.Enhancing development of the herbivorous animals is important to alleviate the contradiction for fighting food between human and animal.The economic is developed in southern China,and the demands for products of herbivorous animal are increasing,however,the lack of high-quality forage and the year-round supplement of high-quality roughage become the bottleneck of the development of herbivores in southern China.The utilization of crops straw and agricultural by-products as livestock feed are particularly important for the development of herbivorous animal in this area.Firstly the fermentation quality of mixed silage of crops straw and agricultural by-products in the Jiangsu and Zhejiang provinces was evaluated.And then fermentation quality parameters were analyzed by correlation and principal component analysis to predict and evaluate the fermentation quality of mixed silage of local crops straw and agricultural by-products.The research contains eight chapters as follow:1 The chemical compositions of rice straw,corn stover and agricultural by-productsThe chemical compositions of rice straw,corn stover,and main agricultural by-products(sweet potato vine,broccoli residues,cabbage waste leaves,carrot waste,citrus peel and wet brewers’ grains)in Jiangsu and Zhejiang Provinces were analyzed,which provided the basis for the ratios of mixed silage.The results showed that rice straw and apple pomace had higher dry matter(DM)contents(>800 g kg-1 fresh weight,FW)but lower crude protein(CP)and water-soluble carbohydrate(WSC)contents.Sweet potato peel,sweet potato vine,wet brewers’ grains,broccoli residues,cabbage waste leaves,and carrot waste had lower DM contents(<100 g kg-1DM).Cabbage waste leaves,citrus peel,carrot waste,corn stover,and sweet potato peel were rich in WSC contents(>100 g kg-1 DM),while the alfalfa,broccoli residues,and wet brewers’ grains showed higher CP contents(>200 g kg-1 DM).2 Fermentation qualities of mixed ensilage rice straw,alfalfa and local vegetable by-productsFermentation qualities of mixed silages of rice straw,alfalfa,and broccoli residues or cabbage wasted(5:1:4 of FW)during ensiling were assessed.The results showed that mixed silage of rice straw,alfalfa,and broccoli residues had high pH(4.96),and the butyric acid(BA)concentration and ammonia nitrogen/total nitrogen(AN/TN)in 30d mixed silage were 2.41 g kg-1 DM and 229 g kg-1 TN,respectively,which indicated the inferior preservation quality of the mixed silage.For the mixed silage of rice straw,alfalfa,and cabbage wasted,pH and AN/TN were 3.81 and 25.1 g kg-1 TN,respectively.The lactic acid content(LA)was 61.6 g kg-1 DM,and no BA was detected over the ensiling process.Then molasses(0,2.5%,5%of fresh weight)was added to mixed silage of rice straw and broccoli residues to improve the fermentation quality.The addition of molasses significantly(P<0.05)enhanced LA fermentation and decreased pH,AN/TN and total volatile fatty acids(TVFAs)contents,resulted in the decline of dry matter loss(P<0.05).There was no significant(P>0.05)difference in pH,LA content and AN/TN between mixed silage with 2.5%and 5%molasses.It was suggested that 2.5%molasses was effective for improving the fermentation quality of mixed ensilage of rice straw,alfalfa and broccoli residues.3 Fermentation quality of mixed silage of rice straw and sweet potato by-productsThe fermentation qualities of mixed silage of rice straw,apple pomace,and sweet potato by-products were evaluated in this chapter.The rice straw and apple pomace were ensiled with sweet potato peel(or sweet potato vine)at the ratios of 5:2:3 for 30 days.The results showed that pH of the mixed silage with sweet potato by-products declined to about 4.0 on day 3 of ensiling,and then maintained the low pH until the end of ensilage for the mixed silage with sweet potato peel,however,the pH significantly(P<0.05)increased to 4.75 on day 30 of ensiling for the mixed silage with sweet potato vine.BA was not detected in both silages during ensiling.The mixed silage with sweet potato vine had higher AN/TN during ensiling and reached 63.5 g kg-1 TN at the end of ensiling.Then wet distillers’ grains were ensiled with the mixed silage at 0,10%,20%and 30%(FW).The addition of wet distillers’ grains significantly(P<0.05)decreased the pH,DM,WSC contents and ratios of lactic acid/acetic acid(LA/AA),while increased LA and acetic acid(AA)contents as compared to the control.The inclusion of wet distillers’ grains increased AN/TN for mixed silages with sweet potato peel,and the AN/TN in mixed silage included with 20%wet distillers’grains are twice of that in control.The wet distillers’grains significantly(P<0.05)declined AN/TN for mixed silage of rice straw and sweet potato vine.4 Study on fermentation quality of mixed silage of rice straw and fruits by-productsThe rice straw and apple pomace were ensiled with citrus peel at the ratios of 5:2:3,and the dynamics of fermentation qualities of mixed silage were evaluated during 30 days of ensiling.The pH was declined below 4.0 on day 3 of ensiling and remained this value until the end of ensiling.The AN/TN was slowly increased to 63.6 g kg-1 TN,and BA was not detected during ensiling.Then wet distillers’ grains were ensiled with the mixed silage of rice straw,apple pomace,and citrus peel at 0,10%,20%and 30%(FW).The LA content in mixed silage with wet distillers’ grains significantly(P<0.05)increased after 5 days of ensiling,while that in control slowly increased during ensiling.The AN/TN in mixed silage with wet distillers’ grains were significantly(P<0.05)lower than that of control.5 Fermentation quality of mixed silage of corn stover,alfalfa with local vegetable by-productsThe corn stover and apple pomace were ensiled with Broccoli residues(cabbage residues or carrot wastes)at the ratios of 2:1:1,and the dynamics of fermentation qualities of mixed silage were evaluated during ensiling.All mixed silages showed well fermentation quality,indicated by lower pH(3.55～3.98)and AN/TN(22.7～56.6 g kg-1 TN),higher LA concentrations(38.9～69.3 g·kg-1 DM)and LA/AA(2.09～7.84).The propionic acid(PA)and BA contents were not detected in all mixed silages during ensiling.6 Fermentation quality of mixed silage of corn stover and sweet potato by-productsThe fermentation qualities of mixed silage of corn stover and sweet potato by-products were evaluated.Firstly,the corn stover and apple pomace were ensiled with sweet potato peel(or sweet potato vine)at the ratios of 2:1:1 for 30 days,and the mixed silage with sweet potato peel showed lower pH(3.57)and AN/TN(20.6 g·kg-1 TN),and there were no PA and BA contents in the silage during ensiling.For the mixed silage with sweet potato vine,the pH rapidly declined during the earlier stage of ensiling due to the sufficient fermentation substrate.After 14 days of ensiling,the pH and BA content was sharply increased(P<0.05),and the fermentation quality of mixed silage with sweet potato vine was inferior.Then,wet distillers’ grains were ensiled with the mixed silage of corn stover and sweet potato by-products,the mixed silage of corn stover,sweet potato peel and wet distillers’ grains had higher LA,AA and VFAs concentrations,neither PA nor BA content was detected in the mixed silages during the ensiling.For mixed silage of corn stover and sweet potato vine,the inclusion of wet distillers’ grains increased(P<0.05)the LA concentration and decreased(P<0.05)the pH and BA concentration.After 30 days of ensiling,the AN/TN in mixed silage included with 10%or 20%wet distillers’ grains were significantly(P<0.05)lower,while the mixed silage included with 30%wet distillers’grains had significantly(P<0.05)higher AN/TN than mixed silage without wet distillers’grains7 Fermentation quality of mixed silage of corn stover and fruits by-productsFirstly the corn stover,apple pomace,and citrus peel were ensiled at the ratios of 2:1:1 for 30 days,and the dynamics of fermentation qualities of mixed silages were evaluated.The pH were declined below 4.0 on day 1 of ensiling and remained this value until the end of ensiling,and the mixed silage maintained higher LA/AA and lower AN/TN during the ensiling.Then the mixture ensiled with different percentages of wet distillers’grains(10%,15%,20%FW).There were no significant difference(P>0.05)in DM content and pH during the ensiling.The LA concentration in mixed silage with wet distillers’ grains begin to higher than control,however,there was no significant difference(P>0.05)in LA concentration between mixed silage with wet distillers’ grains.There were only trace amount of PA or BA content in all silages.The AN/TN was increased with the increase of proportions of wet distillers’ grains.The AN/TN in the mixed silage inclusion of 20%wet distillers’ grains was only 16.11 g·kg-1 TN,but it was significantly(P<0.05)higher than control.8 The correlation and principal component analysis of mixed silage of agricultural straw and by-productsThe fermentation parameters of mixed silage of agricultural straw and by-products were analyzed by correlation and regression analysis.The results indicated that a regression model including WSC and DM content could explain the variation in LA content of mixed silage,while the pH,AA and VFAs concentrations of mixed silage could be predicted by the quadratic regression equation of WSC content.The fermentation parameters of mixed silage were analysed by principal component analysis,and the mixed silage inclusion of corn stover showed higher fermentation quality than mixed silage with rice straw;among all of the agricultural by-products,citrus peel had the best fermentation potential,followed by cabbage residues or carrot wastes,which were better than sweet potato peel,while sweet potato vine was the worst one.The addition of molasses obviously improved the fermentation quality of corresponding silages. |
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