摘要
本试验旨在研究不同比例大叶枸草粉替代基础混合饲粮中的苜蓿草粉、豆粕、玉米及混合精料对瘤胃体外产气和发酵特性的影响,探讨大叶枸草粉替代常规饲料的适宜比例。选用3头体况良好并装有瘤胃瘘管的青年湖羊作为瘤胃液供体动物,分4个试验(大叶枸草粉100%替代苜蓿草粉、25%～100%替代豆粕、10%～40%替代玉米或混合精料),每个试验设均空白对照,用体外产气法观测各基础混合饲粮的24 h体外发酵参数的变化。结果表明:与空白对照相比,大叶枸草粉100%替代苜蓿草粉时,体外24 h产气量、pH、氨态氮浓度无显著差异(P>0.05),但是总挥发性脂肪酸(TVFA)浓度显著降低(P<0.05),而各挥发性脂肪酸(VFA)与TVFA比值差异不显著(P>0.05);用50%的大叶枸草粉替代豆粕时,对24 h产气量和发酵参数均无显著影响(P>0.05),而高替代比例时显著降低24 h产气量、pH及氨态氮浓度(P<0.05);随着大叶枸草粉替代玉米比例增加,24 h产气量无显著变化(P>0.05),pH、氨态氮浓度显著上升(P<0.05),而TVFA浓度显著下降(P<0.05),乙酸/TVFA显著上升(P<0.05),丙酸/TVFA下降,但差异不显著(P>0.05);大叶枸草粉替代混合精料时,pH、氨态氮浓度无显著差异(P>0.05),用20%以内的大叶枸草粉替代混合精料,对24 h产气量和发酵参数(除乙酸/丙酸)无显著影响(P>0.05),当替代比例高于40%时会显著降低24 h产气量和TVFA浓度(P<0.05)。可见,湖羊基础混合饲粮中用大叶枸草粉100%替代苜蓿草粉时,在瘤胃发酵特性上没有差异;以50%的大叶枸草粉替代豆粕,对瘤胃发酵参数影响不显著;而替代玉米或混合精料的比例不应超过20%。
The objective of this study was to investigate the effects of alfalfa meal, soybean meal, maize and concentrate mixture replaced by big leaf mulberry meal on rumen in vitro fermentation characteristics, and to obtain the optimal replacement ratio. The rumen fluid was collected from four castrated young Hu sheep fitted with permanent rumen fistulas. The study contained 4 experiments, the big leaf mulberry meal was used to re- place 100% alfalfa meal, 25% to 100% soybean meal and 10% to 40% maize or concentrate mixture, re- spectively, and every experiment had a control. In vitro gas production test was performed to determine the ru- men fermentation parameters in 24 h. The results showed as follows： compared with the control, no significant differences were observed in the pH, gas production in 24 h and ammonia-N concentration when 100% alfalfa meal was replaced by big leaf mulberry meal （ P 〉 0.05 ）, but the concentration of total volatile fatty acids （TVFA） was significantly decreased （P 〈 0.05 ）, and the ratios of volatile fatty acids （VFA） to TVFA were not significantly different （ P 〉 0.05）. The gas production in 24 h and rumen fermentation parameters did not change when 50% soybean meal was replaced by big leaf mulberry meal （P 〉 0.05 ）, while the higher re- placement ratio significantly reduced gas production in 24 b, pH and ammonia-N concentration （ P 〈 0.05 ）. With the increase of replacement ratio of big leaf mulberry meal to maize, gas production in 24 h did not change （ P 〉 0.05 ）, but the pH and ammonia-N concentration were significantly increased （ P 〈 0.05 ）, while TVFA concentration was significantly decreased （ P 〈 0.05 ） , acetate/TVFA was significantly increased （ P 〈 0.05）, and propionate/TVFA was decreased, but was not significantly different （ P 〉 0.05 ）. No statistical differences were observed in pH and ammonia-N concentration when concentrate mixture was replaced by big leaf mulberry meal （ P 〉 0.05 ）. The replacement ratio less than 20% did not change the gas production in 24 h and fermentation parameters （except acetate/propionate） （P 〉 0.05 ）, but the replacement ratio higher than 40% significantly reduced gas production in 24 h and TVFA concentration （P 〈0.05）. From the above results, it is inferred that there is no significant difference in rumen in vitro fermentation characteristics when 100% alfalfa meal is replaced by big leaf mulberry meal, and the influences on rumen fermentation parameters are not significant when 50% soybean meal is replaced by big leaf mulberry meal, while replacement ratio of maize or concentrate mixture should not exceed 20%.
出处
《动物营养学报》
CAS
CSCD
北大核心
2013年第2期397-405,共9页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
金华市科技局项目:饲草大叶枸对反刍动物饲用价值的系统评估及产品开发(2011-2-029)
关键词
大叶枸草粉
产气量
瘤胃发酵
big leaf mulberry meal
gas production
rumen fermentation
