不同厚度蒸汽压片处理对玉米活体外瘤胃发酵的影响

Effect of Various Thickness Steam-flaked Processing on Ruminal Fermentation of Corn Grains in vitro

试验以未处理的玉米及两种不同厚度蒸汽压片玉米(压片厚度为1.5mm,SFC 1.5;压片厚度为2.0mm,SFC 2.0)为材料,采用营养成分分析、活体外人工瘤胃产气量试验,研究不同厚度蒸汽压片处理对玉米营养成分、淀粉糊化度和活体外发酵特性的影响。结果表明,不同厚度蒸汽压片处理显著降低玉米粗蛋白质和粗脂肪含量(P<0.05),显著提高了玉米的淀粉糊化度(P<0.05);并且显著提高了玉米在瘤胃液内的淀粉降解率和体外产气速度(P<0.05),显著降低了瘤胃液中氨态氮(NH3-N)浓度(P<0.05);降低压片厚度(1.5和2.0mm),蒸汽压片玉米淀粉糊化度增加约17%(88.76%和71.60%),SFC 1.5的体外产气速度、4h干物质和淀粉产气率显著高于SFC 2.0(P<0.05)。不同厚度蒸汽压片处理对玉米瘤胃48h产气量、12和24h瘤胃液pH、总挥发性脂肪酸产量及乙酸、丙酸、乙酸/丙酸、异丁酸、异戊酸、戊酸摩尔比影响均不显著(P>0.05)。综上所述,不同厚度蒸汽压片处理可显著提高玉米在瘤胃内淀粉降解率和降解速度,降低瘤胃液中氨态氮浓度,而对48h产气量及其他发酵参数没有明显影响。

Various unprocessed corn, steam-flaked corn （thickness 1.5 mm, SFC 1.5）, and steam flaked corn （thickness 2.0 mm,SFC 2.0） was used in the present study to compare the chemical compositions, starch gelatinization and ruminal fermentation characteristics in vitro of corn grains as affected by various processing based on chemical analysis,in vitro ruminal fermentation and gas production method. The results showed that the contents of crude protein and ether extract decreased （P〈0.05）, but the starch gelatinization increased （P〈0.05）;Gas production rate and starch digestibility of SFC were higher than unprocessed corn （P〈0.05）, but NH3-N concentrations were lower （P〈0.05）;The starch gelatinization of SFC 1.5 （88.76%） increased by 17% than that of SFC 2. 0 （71. 60%）;The gas production rate, the digestibility of dry matter and starch of SFC 1.5 in 4 h significantly increased than that of SFC 2.0 （P〈0.05）. No differences on 48 h gas production, 12 and 24 h pH,total VFA production, the molar proportion of acetate,propionate, acetate/propionate, isovaler that the various thickness steam-flaked ate,isobutyrate and valerate （P〉0. 05）. It was concluded corn tion rate, slow ruminal ammonia release, but grains could increase starch digestihil would not affect 48 h gas production ity and degrada- and other ruminal fermentation traits.