| The trial was conducted to assess the effects of enzymatic hydrolysis invitro of β-mannanase on protein feed stuffs from different sources and filtrate theoptimum supplementing level in the first step by imitating the digestive tractenvironment of weaned piglets. Then by feeding test of animals to research the effectsof β-mannanase on growth performance and apparent digestibility of nutrients ofweaned piglets in low energy diets and screen the best level of β-mannanase finally.1. Study on the effects of enzymatic hydrolysis in vitro of β-mannanase onprotein feed stuffs from different sources.The trial was carried out to research theeffects of enzymatic hydrolysis of β-mannanase on soybean meal (SBM), cottonseedmeal (CSM) and rapeseed meal (RSM) from different sources through digestion testin vitro. Nine single-factor experiment designs were employed. Every protein feedstuff was incubated with5β-mannanase different level with4replicates, respectively.The results showed that:1) There was a certain difference on the content of the totalmannan and soluble mannan of the same protein feed stuff from different sources.Thetotal mannan and soluble mannan levels were influenced by the kind of feeds. Thecontent of the total mannan and soluble mannan of SBM was higher than that of CSMand RSM.2) There was a definite diversity on the effects of β-mannanase on the sameprotein feed stuff from different sources. There were significant enzymatic hydrolysiseffects of β-mannanase on the mannan of three different kind of protein feed stuffs.Compared to RSM and CSM, the disaggregation effects of β-mannanase on SBMwere the best, on the contray.3) The reference levels of β-mannanase for three kind ofSBM from Henan, Hebei and Shandong were3000U/kg,3000U/kg and2000U/kgrespectively based on the production quantity of the mannose of SBM. The referencelevels of β-mannanase for three kind of CSM from Henan, Xinjiang and Hubei were3000U/kg,2000U/kg and3000U/kg respectively based on the production quantityof the mannose of CSM. The reference levels of β-mannanase for three kind of RSMfrom Xiangyang, Qinghai and Yihai were3000U/kg,3000U/kg and2000U/kgrespectively based on the production quantity of the mannose of RSM. 2. The Effects of β-mannanase on growth performance, apparent digestibility ofnutrients and comprehensive economic efficiency of weaned piglets in low energydiets.The experiment was devised to3×4×10design.120healthy piglets (body weightis13.95±0.29kg) from crossed (Duroc×Landrace×Yorkshire) were selected anddivided into4groups randomly. The control group was defined to A, and received thebasal diets. The treatment B and treatment C received the low energy dietssupplemented with100g/t,200g/t β-mannanase respectively. The low energy dietswere decreased by60kcal/kg of DE on the basis of the basal diets. The resultsshowed that:1) Comparing with the control group, there was no significant effect oftreatment B and treatment C on ADG, but the ADG of treatment B and treatment Cwas increased by7.9%and9.3%compared to the control group respectively (p>0.05).Comparing with the control group, there was no significant effect of treatment B andtreatment C on FCR, but the FCR of treatment B and treatment C was decreased by2.5%and3.5%compared to the control group respectively (p>0.05). Comparing withthe control group, the diarrhea rate of treatment B and treatment C were reducedsignificantly (p<0.05), and the diarrhea rate would be lower when supplementedβ-mannanase with higher levels.2) Comparing with the control group, the apparentdigestibility of DM, Ash, CP, P and GE of treatment B was improved by5.33%(p<0.05),8.34%(p<0.05),7.12%(p<0.05),6.31%(p<0.05) and5.53%(p<0.05)respectively. The apparent digestibility of DM, Ash, CP, P and GE of treatment C wasimproved by5.33%(p<0.05),8.34%(p<0.05),7.12%(p<0.05),6.31%(p<0.05) and5.53%(p<0.05) compared to the control group respectively. The was no significanteffect among treatment B, treatment C and the control group on the apparentdigestibility of Ca and EE (p>0.05), but they had a increasing trend compared to thecontrol group.3) Comparing with the control group, costs of feed of treatment B andtreatment C were decreased by74RMB/t and74.5RMB/t respectively, but costs offeed of weight gain of treatment B and treatment C were reduced by0.25RMB/kgand0.27RMB/kg respectively. The comprehensive economic efficiency of treatmentB and treatment C was improved6.9%and7.5%respectively.In conclusion: Theresults showed that100g/t of β-mannanase addition to the low energy diets couldimprove the growth performance, apparent digestibility of nutrients andcomprehensive economic efficiency, and lower the diarrhea rate of weaned piglets. |
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