玉米品种及其玉米醇溶蛋白含量对山羊瘤胃淀粉降解率的影响

Species and Zein Content of Corn: Effects on Ruminal Starch Degradation Rate in Goats

本试验旨在研究不同品种饲用玉米及其玉米醇溶蛋白(zein)含量对山羊瘤胃淀粉降解率的影响。运用新比浊法测定8个内蒙古地区代表性的饲用玉米品种(久龙10号、久龙15号、登海3672、德丰359、京单58、丰田6号、种星2255、富尔306)的zein含量,并通过尼龙袋法和体外法测定山羊瘤胃淀粉有效降解率和7 h体外淀粉降解率。结果表明:1)京单58 zein含量[(3.09±0.36)%]最低,而瘤胃淀粉有效降解率[外流速率常数(Kp)=6%/h时,(43.11±0.04)%;Kp=4%/h时,(49.33±0.07)%]和7 h体外淀粉降解率[(62.08±1.24)%]均居8个品种之首;德丰359 zein含量[(6.04±0.32)%]最高,而瘤胃淀粉有效降解率[Kp=6%/h时,(35.91±0.03)%;Kp=4%/h时,(39.64±0.05)%]和7 h体外淀粉降解率[(52.93±0.42)%]均最低。2)玉米中zein含量和7 h体外淀粉降解率呈极显著的负相关关系(R2=0.89,P<0.01);与瘤胃淀粉有效降解率亦呈极显著的负相关关系(Kp=6%/h时,R2=0.82,P<0.01;Kp=6%/h时,R2=0.83,P<0.01)。3)玉米中zein含量(A)和淀粉含量(B)与7 h体外淀粉降解率(Y)的回归关系极显著,公式为:Y(%)=58.73+0.19B-2.68A(R2=0.94,P<0.01);而与瘤胃淀粉有效降解率(Y')的回归关系显著,公式为:Y6'(%)=47.84+0.04B-2.43A(Kp=6%/h时,R2=0.82,P<0.05),Y4'(%)=55.99+0.04B-3.29A(Kp=4%/h时,R2=0.83,P<0.05)。结果提示,为提高玉米饲用价值和节约成本,十分必要从玉米的种植到饲喂动物整个链条来考虑品种和zein含量对反刍动物消化道淀粉降解率的影响。

This experimental was conducted to research the effects of different species and zein content of corn for feeding on ruminal starch degradation rate in goats. Zein content of 8 representative species of corn grains in Inner Mongolia region （Jiulong No. 10, Jiulong No. 15, Denghai 3672, Defeng 359, Jingdan 38, Feng-tian No. 6, Zhongxing 2255 and Fuer 306） was determined by nephelometry method, and ruminal starch deg-radation rate and 7 h in vitro starch degradation rate （7 h IVSD） in goats were determined by nylon bag and in vitro methods, respectively. The results showed as follows： 1 ） Jingdan 58 had the lowest zein content [（3. 09 ＆#177; 0. 36）%], and the highest ruminal starch efficient degradation rate [when outflow rate constant （Kp） =6%/h, （43. 11 ＆#177; 0. 04）%, when Kp =4%/h,（49. 33 ＆#177; 0. 07）%] and 7 h IVSD [（62. 08 ＆#177; 1. 24）%]; meanwhile, Defeng 359 had the highest zein content [（6. 04 ＆#177;0. 32）%], and the lowest ruminal starch efficient degradation rate [ when Kp =6%/h, （ 35. 91 ＆#177; 0. 03 ）%; when Kp =4%/h, （ 39. 64 ＆#177; 0. 05）%] and 7 h IVSD [（52. 93 ＆#177;0. 42）%]. 2） Corn zein content had a significantly negative relationship with 7 h IVSD （R2 =0. 89, P〈0. 01）, and had a significantly negative relationship with ruminal starch effi-cient degradation rate （when Kp=6%/h, R2 =0. 82, P〈0. 01; when Kp =4%/h, R2 =0. 83, P〈0. 01）. 3） Zein （ A） and starch contents of corn （ B） had a significant regression relationship with 7 h IVSD （ Y） [Y（%） =58. 73＋0. 19B-2. 68A（R2 =0. 94,P〈0. 01）], and had a significant regression relationship with ruminal starch efficient degradation rate [Y6′（%） =47. 84＋0. 04B-2. 43A （when Kp=6%/h, R2 =0. 82, P〈0. 05）; Y4′ （%） =55. 99 ＋0. 04B-3. 29A （when Kp=4%/h,R2 =0. 83, P〈0. 05）. In conclusion, in order to improve feeding value and save costs of corn, it is very important to control the effects of species and zein content of corn on the total digestive tract starch degradation rate in ruminants from the whole process from planting to feeding.