不同精粗比日粮对雷州山羊体外瘤胃发酵的影响

Effects of Diets with Different Concentrate to Forage Ratios on in Vitro Rumen Fermentation of Leizhou Goats

本试验通过体外发酵法,探讨皇竹草和精料以不同比例配制成的全混合日粮(TMR)对雷州山羊体外瘤胃发酵的影响。试验采用精料与皇竹草按干物质0∶100(Ⅰ组)、10∶90(Ⅱ组)、20∶80(Ⅲ组)、30∶70(Ⅳ组)和40∶60(V组)比例配制日粮,在体外发酵的第4、8、12、24和48h取样分析其发酵参数的变化,为皇竹草在雷州山羊TMR中的应用提供参考。结果显示,(1)随着精粗比的提高,粗蛋白质含量逐渐增高,纤维物质、粗灰分含量逐渐降低,且4、8、24、48h累积产气量呈现极显著增长(P<0.01)。(2)随着发酵时间和精料添加比例的增加,瘤胃pH呈下降趋势,同一时间点,Ⅳ、Ⅴ组pH均显著低于Ⅰ、Ⅱ组(P<0.05);干物质降解率呈上升趋势,同一时间点,Ⅳ、Ⅴ组的降解率均极显著高于Ⅰ、Ⅱ组(P<0.01);48h的氨态氮浓度均高于4h,4、24h时各组间均无显著差异(P>0.05)。(3)pH与累积产气量和干物质降解率呈显著或极显著的负相关,累积产气量与干物质降解率呈显著或极显著的正相关(P<0.05;P<0.01);各个发酵时间pH与干物质、粗灰分、粗纤维、中性洗涤纤维和酸性洗涤纤维呈显著或极显著正相关,与粗蛋白质呈显著或极显著负相关(P<0.05;P<0.01);累积产气量和干物质降解率与TMR日粮粗蛋白质含量呈显著或极显著正相关,与干物质、粗灰分、粗纤维、中性洗涤纤维和酸性洗涤纤维呈显著或极显著负相关(P<0.05;P<0.01)。综上,在本试验条件下,精料和皇竹草的比例为30∶70时,可获得较好的发酵效果,且可节约成本。

This study was conducted to study the effect of different ratios of concentrate to Pennisetum sinese Roxb in diet on in vitro rumen fermentation in Leizhou goats.In vitro fermentation method was used and diets with different concentrate to Pennisetum sinese Roxb were prepared which the ratio were 0∶100（group Ⅰ）,10∶90（group Ⅱ）,20∶80（group Ⅲ）,30∶70（groupⅣ）and 40∶60（groupⅤ）,respectively,and the samples were analyzed after fermented for at 4,8,12,24 and 48h.The results showed that：（1）With the increase of the concentration to roughage ratios,the crude protein content of TMR diets increased and the fiber material and crude ash contents decreased gradually.With the increase of concentration,the gas production at 4,8,24,48 hwere extremely significantly increased（P〈0.01）.（2）With the increase of fermentation time and the concentration to roughage ratios,the pH of rumen fluid were decreased,and pH of groupsⅣandⅤ were significantly lower than groupsⅠand Ⅱ at the same time（P〈0.05）.And the dry matter degradation were increased,and that of groups Ⅳ and Ⅴ were extremely significantly higher than groupsⅠandⅡat the same time（P〈0.01）.The NH_3-N content at 48 hwas higher than that at 4hand there was no siginificant difference among groups at 4and 24h（P〈0.05）.（3）The correlation between pH and accumulated gas production,dry matter degradation rate were significantly or extremely significantly negative,that between accumulated gas production and dry matter degradation rate were significantly or extremely significantly positive（P〈0.05;P〈0.01）.The correlation between pH and dry matter,crude ash,crude fiber,neutral detergent fiber and acid detergent fiber were significantly or extremely significantly positive,that with crude protein was significantly or extremely significantly negative（P〈0.05;P〈0.01）.And the correlation between cumulated gas production,dry matter degradation rate and crude protein was significantly or extremely significantly positive,while that with the dry matter,crude ash,crude fiber,neutral detergent fiber and acid detergent fiber were significantly or extremely significantly negative（P〈0.05;P〈0.01）.In summary,under the conditions of this test,the appropriate ratio of concentrate to Pennisetum sinese Roxb was 30∶70in which Leizhou goat could get a better fermentation effect and cost savings.