Study On High-efficient Biological Corn Straw Feed And Its Application In Fatten Pig Production

In order to increase corn straw resource utilization, especially for themonogastric animal production, four experiments were carried out, including the steamexplosion and NaOH pretreatments, microbial fermentation, nutritional value determinationand feeding experiment for pigs. The results were as follows:Experiment1: For increasing corn straw degradation, five strains ofligninase-producing microbes were selected from rotten branches and soil with guaiacol asthe indicator. The results showed that the fifth strain could produce CMCase at116.35U/g,degrade lignin and crude fiber in corn straw by34.95%and20.00%(P<0.05) after5dsolid-state fermentation, compared to other groups. The ligninase activity at10dfermentation medium reached45.64U/g. The fifth strain was identified as Trametes hirsuteby26S rDNA ITS analyses. Aspergillus oryzae stored in our laboratory was also selected forlignocellulose degradation.Experiment2: In order to improve corn straw application, steam explosion, sodiumhydroxide soaking and Aspergillus oryzae fermentation were used. The orthogonalexperiment showed that the best sodium hydroxide pretreatment condition for lignindegradation was to soak the sample in1.5%sodium hydroxide at100℃f or1.5h.Comparedwith the control group, hemicellulose, lignin and cellulose degradation rates in the cornstraw treated with steam explosion treatment were54.68%,33.14%and17.75%;hemicellulose and lignin degradation rates in the corn straw treated with sodium hydroxidewere67.92%and76.54%(P<0.05), while cellulose content was little increased (P<0.05).Hemicellulose, lignin and cellulose degradation rates in the corn straw treated with steamexplosion and sodium hydroxide treatment were75.98%,77.88%and39.93%; while lignincontent in the corn straw treated with sodium hydroxide was113.88%higher than that withsteam explosion (P<0.05); lignin content in the corn straw treated with steamexplosion–sodium hydroxide was135.00%higher than that with steam explosion.Hemicellulose degradation rates in the four groups after6-day microbial fermentation were23.98%,59.02%,85.40%and85.73%, respectively; the cellulose degradation rates were22.98%,47.14%,24.13%和46.46%, respectively; while lignin contents had no significantchange during the whole microbial fermentation. CMCase, amylase and protease activities in the steam exploded and sodium hydroxide soaked corn straw during the whole microbialfermentation were lower than that in the untreated corn straw (P<0.05). The filter papercellulose had the same performance (P＞0.05), but the glucose contents had the oppositechanges (P<0.05). Steam explosion and microbial fermentation was selected by overallconsidering lignocellulose degradation, economic costs and environmental benefits for thefeeding experiment.Experiment3: Four groups were set to determine the apparent digestible energy ofbiological corn straw feedstuff (BCTF). Group1,2,3and4were added with0%,5%,10%and15%BCTF for replacing the same percentage of corn meal，respectively. The resultsshowed the the apparent digestible energy of BCTF was7.51MJ/Kg by slope ratio method.Experiment4: To study the effect of BCTF on fattening pig production afterreplacing corn meal, A2-period feeding program was adopted in the experiment. In the firststage,12090-day-old pigs were assigned to5groups,8pigs for each group consisted of3replicates. In the next stage, a total of105120-day-old pigs were assigned to5groups,7pigs for each group consisted of3replicates. The control group was added with the basaldiet, group1,23was added with5%,10%and15%BCTF for replacing the samepercentage of corn meal, respectively. Group4was added with10%BCTF with the samedigestable energy as the control group.(1)The feeding results showed that the Enzyme activity of pigs intestinal tract wereincrease with BCTF addition increasing.At the sanme time the populations of E. coli isreduced and the populations of Lactic acid bacteria is increaseed,while there were nosignificant differrence among the groups.we also found the enzyme activity of LDH、ASTand AIP in experimental groups were differencnce with the the control group.(2)The feeding results showed that daily gain and nutrient digestibility of pigs weredecreased with BCTF addition increasing. There were no significant differrence for dailygain among the groups (P>0.05). The group with10%BCTF balanced with digestableenergy had the best results of daily gain and economic profits (P<0.05), especially betterthan that with15%BCTF. It could be concluded that it was ideal when BCTF replacing5-10%corn meal with balanced digestable energy in fattening pig diets.