摘要
为探讨不同收获时间对粤西地区青贮玉米青贮品质的影响及不同比例青贮玉米与青贮菠萝渣组合对体外发酵参数的影响,试验采用随机区组设计,共设置3个小区,在青贮玉米生长前期选取具有代表性的植株做标记,于雄蕊开花后第25天开始,每隔4 d每个小区随机选取6株植株,连续8次,分别记为D1(开花后第25天)、D2(开花后第30天)、D3(开花后第35天)、D4(开花后第40天)、D5(开花后第45天)、D6(开花后第50天)、D7(开花后第55天)、D8(开花后第60天)组,测定各组农艺性状后,用真空袋密封,青贮90 d,青贮结束后测定各组发酵品质与营养成分;选择农艺性状和青贮品质相对较好的3组青贮玉米,等比例混匀后与青贮菠萝渣按照不同比例(0∶100,25∶75,50∶50,75∶25,100∶0)混合,添加发酵液后进行体外发酵,每种比例设置4个发酵时间(3,12,24,48 h),每种比例每个发酵时间设置3个重复,发酵结束后,测定体外发酵pH值及挥发性脂肪酸含量。结果表明:随着收获时间的延长,青贮玉米的株高和籽粒重均大体呈现升高趋势,茎重和穗重均呈现先升高后降低的趋势,而绿叶数和总叶面积均呈现降低趋势;其中D4组、D5组和D6组茎重显著高于其他各组(P<0.05),D3组和D4组穗重显著高于其他各组(P<0.05),且D4组的茎重和穗重均最高。各组青贮后的pH值均小于4.2;随着收获时间的延长,各组青贮后可溶性碳水化合物含量大体呈现升高的趋势,乳酸和乙酸含量大体呈现先升高后降低的趋势,其中D6组、D7组和D8组可溶性碳水化合物含量显著高于其他各组(P<0.05),D4组和D5组乳酸含量显著高于其他各组(P<0.05),而D6组乙酸含量显著高于其他各组(P<0.05)。随着收获时间的延长,各组青贮后的粗蛋白、粗脂肪和粗纤维含量大体呈现下降趋势,中性洗涤纤维、酸性洗涤纤维含量大体呈现升高趋势;其中D4组、D5组和D6组的粗蛋白含量在6.78%~7.16%之间,中性洗涤纤维含量在34.65%~39.26%之间,酸性洗涤纤维含量在19.31%~24.37%之间。随着发酵时间的延长,各比例青贮玉米与青贮菠萝渣组合的pH值均呈现降低趋势,但相同发酵时间各比例青贮玉米与青贮菠萝渣组合的pH值均差异不显著(P>0.05);当体外发酵时间为12~48 h时,各比例青贮玉米与青贮菠萝渣组合的pH值均在6.44~6.88之间。随着体外发酵时间的延长,各比例青贮玉米与青贮菠萝渣组合的乙酸、丙酸、丁酸含量均呈现先升高后下降的趋势。当发酵时间为24 h和48 h时,比例为75∶25的青贮玉米与青贮菠萝渣组合乙酸、丙酸、丁酸含量均最高,且均显著高于其他各组(P<0.05)。说明青贮玉米与青贮菠萝渣组合饲料产生了一定的正组合效应;在本试验条件下,粤西地区青贮玉米在雄蕊开花后第40~50天收获较为适宜,且在发酵后期(24~48 h)比例为75∶25的青贮玉米与青贮菠萝渣组合的体外发酵挥发性脂肪酸含量最高。
To investigate the effects of different harvest time on silage quality of silage maize in Western Guangdong Region and the effects of different proportions of silage maize and pineapple residue combinations on in vitro fermentation parameters,a randomized block design in the experiment was adopted with a total of three plots.Representative plants were selected for marking in the early growth stage of silage maize.From the 25 th day after stamen flowering,6 plants were randomly selected from each plot every 4 days for 8 consecutive times.They were divided into D1(the 25 th day after stamen flowering),D2(the 30 th day after stamen flowering),D3(the 35 th day after stamen flowering),D4(the 40 th day after stamen flowering),D5(the 45 th day after stamen flowering),D6(the 50 th day after stamen flowering),D7(the 55 th day after stamen flowering)and D8(the 60 th day after stamen flowering)groups.After measuring the agronomic traits of each group,the plants were sealed with vacuum bags and silaged for 90 days.At the end of silage,the fermentation quality and nutrient composition of each group were determined.Three groups of silage corn with relatively good agronomic traits and silage quality were selected and mixed in equal proportion.Then it was mixed with silage pineapple residue in different ratios(0∶100,25∶75,50∶50,75∶25,100∶0),and fermented in vitro after adding fermentation broth.Each ratio was set for 4 fermentation times(3,12,24,48 h).Three replicates were set for each ratio and each fermentation time.After fermentation,the pH value and volatile fatty acid content in vitro were measured.The results showed that plant height and grain weight of silage maize generally showed an increasing trend with the extension of harvest time,and stem weight and ear weight increased first and then decreased,while the number of green leaves and total leaf area decreased.The stem weight of groups D4,D5,and D6 was significantly higher than that of the other groups(P<0.05).The panicle weight of groups D3 and D4 was significantly higher than that of the other groups(P<0.05),and the stem weight and panicle weight of group D4 were the highest.The pH value of each group after ensiling was less than 4.2.With the prolongation of harvest time,the content of WSC in each group showed an increasing trend after silage;the content of lactic acid and acetic acid showed a trend of increasing first and then decreasing,and there was no significant change in NH3-N.The content of WSC in groups D6,D7 and D8 was significantly higher than that in other groups(P<0.05).The content of lactic acid in groups D4 and D5 was significantly higher than that in other groups(P<0.05),while the content of acetic acid in group D6 was significantly higher than that in other groups(P<0.05).With the extension of harvest time,the contents of crude protein,crude fat and crude fiber in each group showed a downward trend;the contents of neutral detergent fiber and acid detergent fiber showed an upward trend,and the contents of calcium and phosphorus did not change significantly.Among them,the crude protein content of D4,D5 and D6 was between 6.78% and 7.16%,the neutral detergent fiber content was between 34.65% and 39.26%,and the acid detergent fiber content was between 19.31% and 24.37%.With the extension of fermentation time,the pH value of all proportions of silage corn and silage pineapple residue combinations showed a downward trend,but there was no significant difference in pH value of all proportions of silage corn and silage pineapple residue combinations at the same fermentation time(P>0.05).When the fermentation time was 12-48 h in vitro,the pH values of the combination of silage corn and silage pineapple residue in all proportions were between 6.44 and 6.88.With the extension of fermentation time in vitro,the contents of acetic acid,propionic acid and butyric acid in the combination of silage corn and silage pineapple residue of all proportions increased first and then decreased.When the fermentation time was 24 h and 48 h,the content of acetic acid,propionate and butyric acid of the combination of silage corn and silage pineapple residue with the ratio of 75∶25 was the highest,which was significantly higher than that of the other groups(P<0.05).The results indicated that the combination of silage corn and silage pineapple residue produced a certain positive combination effect,and the harvest time of silage maize at the 40 th-50 th days after stamen flowering was suitable in Western Guangdong Region,and the combination of silage maize and silage pineapple residue with a ratio of 75∶25 in the late fermentation stage(24-48 h)had the highest content of volatile fatty acids during in vitro fermentation under the experimental conditions.
作者
王胜男
杨伟光
王嘉麟
吴鹏鑫
邱晓媛
许悦雯
尹福泉
WANG Shengnan;YANG Weiguang;WANG Jiain;WU Pengxin;QIU Xiaoyuan;XU Yuewen;YIN Fuquan(Binhai Agricultural College,Guangdong Ocean University,Zhanjiang 524088,China)
出处
《黑龙江畜牧兽医》
CAS
北大核心
2022年第24期101-107,共7页
Heilongjiang Animal Science And veterinary Medicine
基金
2020年广东省科技专项资金(“大专项”+“任务清单”)项目
广东省现代草牧业(羊)产业技术体系项目(2019KJ127)
广东省教育厅项目“华南农业大学—广东海洋大学高校服务乡村振兴共同体黑山羊养殖协同服务”(2020A03025)
2021年广东省科技专项资金(“大专项”+“任务清单”)竞争性分配项目“粤西地区全株青贮玉米种质资源引进、高效生产及饲用价值研究”(2021A05209)。
关键词
青贮玉米
收获时间
菠萝渣
青贮品质
体外发酵
silage corn
harvest time
pineapple residue
quality of silage
in vitro fermentation
