Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

火龙果皮与苜蓿、精料配比对饲料组合效应的研究

本试验旨在探讨火龙果皮与苜蓿、精料配比对饲料组合效应(AE)的影响。试验采用体外产气法测定在精粗比分别为40∶60和30∶70时,精料∶火龙果皮∶苜蓿分别为40∶60∶0、40∶45∶15、40∶30∶30、40∶15∶45、40∶0∶60和30∶70∶0、30∶55∶15、30∶40∶30、30∶25∶45、30∶10∶60、30∶0∶70时11种饲料组合及3种单独饲料(精料、火龙果皮、苜蓿)分别培养0、2、4、6、9、12、24、36、48 h的产气量(GP),培养结束后的上清液及残渣用以测定pH、总挥发性脂肪酸(TVFA)与氨态氮(NH3-N)含量、干物质降解率(DM D)和有机物降解率(OM D),并计算出各指标的单项组合效应指数(SFAEI)和综合组合效应指数(MFAEI)。结果表明:精粗比为40∶60时,40∶60∶0、40∶45∶15组24 h产气量(GP24 h)、DMD、OMD的SFAEI显著或极显著高于其他各组(P<0.05或P<0.01),40∶60∶0、40∶45∶15、40∶30∶30组TVFA和NH3-N的SFAEI显著或极显著高于其他各组(P<0.05或P<0.01),40∶60∶0、40∶45∶15组的MFAEI极显著高于其他各组(P<0.01)。精粗比为30∶70时,30∶70∶0组GP24 h的SFAEI极显著高于其他各组(P<0.01),30∶70∶0、30∶55∶15、30∶40∶30组DM D和TVFA的SFAEI极显著高于其他各组(P <0. 01),30∶70∶0、30∶55∶15组OM D和NH3-N的SFAEI极显著高于其他各组(P <0. 01),30∶70∶0、30∶55∶15、30∶40∶30组的M FAEI极显著高于其他各组(P<0.01)。由此可见,精粗比为40∶60时,精料∶火龙果皮∶苜蓿为40∶45∶15时的M FAEI最大;精粗比为30∶70时,精料∶火龙果皮∶苜蓿为30∶70∶0时的M FAEI最大。     

青稞替代玉米对育肥牦牛生产性能和肉品质的影响

本试验旨在研究青稞替代玉米对育肥牦牛生产性能、屠宰性能、养分表观消化率及肉品质的影响。采用2×3交叉设计,以日粮类型(玉米、60%青稞+40%玉米)和不同精粗比(30∶70、40∶60和50∶50)为两因素,选取36头年龄4周岁左右、体重为(144±21.0)kg的麦洼公牦牛,随机分为6组,每组6个重复,每个重复1头牛。预饲期15d,正试期180d。结果表明:1)日粮类型及精粗比对牦牛生产性能无显著影响(P>0.05)。2)青稞-玉米组的净肉率显著高于玉米组(P<0.05),但屠宰率和眼肌面积无显著差异(P>0.05);精粗比对屠宰性能无显著影响(P>0.05);日粮类型和精粗比二因素对眼肌面积的互作影响显著(P<0.05),以青稞-玉米(40∶60)组效果最优。3)日粮类型对养分表观消化率无显著影响(P>0.05);与30∶70相比,40∶60和50∶50极显著提高了有机物(OM)和总能(GE)的表观消化率(P<0.01)、显著提高了粗蛋白(CP)的表观消化率(P<0.05);日粮类型和精粗比二因素对GE、OM和粗脂肪(EE)的表观消化率有显著的互作影响(P<0.05),以玉米(40∶60)组效果最佳。4)青稞-玉米组和玉米组背最长肌亮度值(L*)、红度值(a*)、pH值均无显著差异(P>0.05),但青稞-玉米组的黄度值(b*)和滴水损失显著低于玉米组(P<0.05)、蒸煮损失极显著低于玉米组(P<0.01);随着精粗比的升高,蒸煮损失有逐渐降低的趋势(P=0.075)。5)日粮类型对背最长肌的嫩度无显著影响(P>0.05);随着精粗比的升高,剪切力逐渐减小(P>0.05),肌纤维直径有减小的趋势(P=0.059),肌纤维密度显著增加(P<0.05),肌纤维面积显著减小(P<0.05)。综上所述,以青稞替代日粮中60%的玉米能够提高育肥牦牛的屠宰性能,改善牦牛肉的品质;日粮精粗比为40∶60时饲喂效果最佳。     

玉米芯与苜蓿、精料配比对饲粮组合效应的影响

为了探讨玉米芯与苜蓿、精料间不同配比对饲粮组合效应(associative effects, AE)的影响。采用体外产气法测定在精粗比40∶60和30∶70时,精料∶玉米芯∶苜蓿分别为40∶60∶0、40∶45∶15、40∶30∶30、40∶15∶45、40∶0∶60和30∶70∶0、30∶55∶15、30∶40∶30、30∶25∶45、30∶10∶60、30∶0∶70时各饲料组合及各种单独原料分别培养2,4,6,9,12,24,36,48 h的产气量(gas production, GP),培养结束后的上清液及残渣用以测定pH、挥发性脂肪酸(volatile fatty acids,VFA)、氨态氮(NH_3-N)、干物质降解率(dry matter digestibility, DMD)和有机物降解率(organic matter digestibility, OMD),并通过各组合的加权估算值计算出各指标的单项组合效应指数(single factor AE indexes, SFAEI)和综合组合效应指数(multiple-factors AE index, MFAEI)。结果表明:当精粗比为40∶60和30∶70时,玉米芯比例为30、15和10、25、40、55的组在GP、DMD、OMD、NH_3-N、TVFA上显著高于其他组,且有较高的SFAEI (P<0.05,P<0.01),30和10组的MFAEI极显著高于其他各组(P<0.01)。结论:当精料∶玉米芯∶苜蓿为40∶30∶30、30∶10∶60时,饲粮的综合组合效应值最大。     

应用套算法估测肉羊精饲料代谢能

本试验旨在应用套算法建立肉羊精饲料代谢能估测模型。选取66只18月龄体重为(49.6±1.3)kg的杜泊×小尾寒羊F1代去势肉羊,采用完全随机区组设计分为11组,包括1个基础饲粮组和10个试验饲粮组,每组6只羊。通过消化代谢试验(为期8 d)和气体代谢试验(为期3 d)并结合套算法计算10种精饲料的消化能和代谢能,建立精饲料代谢能和其概略养分或可消化养分之间的模型。结果表明,1)10种精饲料总能、酸性洗涤纤维含量与消化能呈显著相关(P0.05),有机物含量与消化能达到极显著相关(P0.01);精饲料概略养分与代谢能之间则无显著相关性(P0.05)。2)10种精饲料的可消化养分与代谢能存在极显著相关(P0.01),所建立的预测方程为:ME=-1.907+1.344DE+1.321DDM-5.347DOM-2.093DADF(R2=0.845,n=60,P0.01);ME=-2.105+1.349DE-6.577DOM(R2=0.842,n=60,P0.01)。[ME为代谢能(MJ/kg),DE为消化能(MJ/kg),DDM为可消化干物质(%),DOM为可消化有机物(%),DA DF为可消化酸性洗涤纤维(%)。]综上所述,本试验条件下无法利用精饲料概略养分预测其代谢能,通过精饲料的可消化养分可准确预测其代谢能。     

垃圾浸出液厌氧处理研究

本研究采用厌氧—好氧生物氧化的工艺技术,自行设计和制造了一套有机玻璃为材料的模拟装置,对垃圾浸出液进行处理研究。经试验结果表明,利用本设计装置处理后的污水,可运到国家农田灌溉的污水排放指标并基本达到国家三类废水的排放指标。该成果已通过市级专家鉴定,并将应用于垃圾场淤出污水的处理工程。     

Experiment Research on Leachate Treatment of Sanitary Landfill for Municipal Solid Waste

It is difficult to treat landfill leachate in China.Traditional biologic method and physical method always have high expenses,or cann''t reach the discharge standards.The authors use a new biologic method to treat landfill leachate,which is the Wood_microbial System from Japan.The system to be digested by 3 aeration tanks and 1 reaction tank.The comparison combine processed wool_dust broken pieces with the certain grain degree size were throw in the tanks.Dirty and organic matter are in the digest tanks through the aeration reaction and aneration reaction repeatedly.In this experiment the speed of wastewater discharge and oxygen supply has been changed, and the change of biologic system and the effect of pollutant are removed. The optimal treatment condition can be found.The experiment shows that the system has a good result,special for nitrogenous.The BOD is average to do away with the rate to amount to 90%,almost reach the second class or third class for leachate standard.But BOD loading should be not beyond 4 kg/(m 3.d),othrwise,the system will not operate in normally.     

秸秆氨化与精料添加对羔羊生产性能的影响

本文报道了小麦秸氨化与精料添加对羔羊生产性能影响的研究结果。麦秸氨化提高了羔羊日增重、秸秆与日粮进食量及精料转化效率,但其提高幅度随日粮精料添加量的提高而减小。提高日粮精料添加水平,羔羊日增重与日粮绝对进食量提高,但精料转化效率在氨化与未氨化组呈不同规律变化:未氨化组持续提高,氨化组呈二次曲线规律变化,且“精料/增重”比最低的日粮精料水平为45％。     

食用醋精抑制亚硝酸盐产生的试验

亚硝酸盐中毒(Nitrite poisonig)是畜禽常发生的一种中毒病。用白菜等含硝酸盐较多的菜类作猪的饲料,因调制加工不合理,会产生大量的亚硝酸盐,喂后引起猪急性中毒,常来不急抢救而死亡,对养猪业危害较大。用食用醋精加入调制白菜的浸泡液中,使其pH值为4时,完全可抑制反硝化细菌的活动,基本上不会产生亚硝酸盐。这是因为醋酸是含有2个碳原子的有机酸,对反硝化细菌毒性大,使菌体内DNA和ATP受到破坏,细菌失去脱氮作用所致。用醋精作调制白菜的抑制剂,会起到预防畜禽亚硝盐中毒的作用。     

重金属元素在湿地生态系统中的迁移与分配

为了解重金属元素在湿地生态系统中的迁移和分配特征,于2011年夏季采集了大庆市龙凤湿地土壤、水、芦苇、鱼等4种样品,采用原子吸收分光光度法测定其中Cu,Cd,Zn,Pb,As和Hg这6种重金属元素的含量水平,应用统计学方法分析了彼此之间的相关关系。结果显示,龙凤湿地环境质量状况良好,土壤重金属含量低于松嫩平原的平均值,水体环境质量低于地表水环境质量Ⅱ级标准;湿地中生存的动、植物对重金属的累积情况各不相同,鱼体重金属的富集情况为:Zn>Cd>Cu>As>Hg>Pb,而芦苇重金属的富集情况则为:Cd>Hg>Zn>Cu>As>Pb。分析表明,土壤重金属含量与植物、鱼体重金属含量之间均存在明显的正相关关系,而水、植物、鱼三者之间虽然也存在一定的正相关关系,但均未达到显著水平。