不同类型黑麦草营养价值评估

Evaluation of nutritional value of different types of ryegrass

文章旨在通过体内外试验评估不同类型黑麦草的营养价值。试验选择平均体重为(66.87±2.34)kg的绵羊12头,随机分成3组,每组4个重复,每个重复1头。3组绵羊分别饲喂新鲜、青贮和晒干黑麦草。经过14 d的饲养试验后收集粪便和牧草样品进行后续分析。结果:晒干黑麦草的干物质、有机物和无氮浸出物含量均表现最高(P<0.05)。新鲜黑麦草粗蛋白质和半纤维素含量较青贮黑麦草分别显著提高42.10%和10.82%(P<0.05)。青贮黑麦草粗脂肪、粗纤维、中性洗涤纤维和酸性洗涤纤维含量显著高于其他两种类型的黑麦草(P<0.05)。新鲜、青贮和晒干黑麦草的粗蛋白质、粗脂肪和粗纤维表观消化率无显著差异(P>0.05)。晒干黑麦草干物质表观消化率较新鲜和青贮黑麦草显著提高6.34%和6.21%(P<0.05),同时晒干黑麦草有机物表观消化率较新鲜黑麦草显著提高6.65%(P<0.05),无氮浸出物表观消化率较青贮黑麦草显著提高15.44%(P<0.05)。当体外代谢能值以MJ/kg有机物表示时,新鲜和青贮黑麦草代谢能值较晒干黑麦草分别显著提高21.34%和22.41%(P<0.05),而当体外代谢能值以MJ/kg干物质表示时,新鲜黑麦草能值最高,青贮黑麦草能值次之,晒干黑麦草能值最低(P<0.05)。结论:新鲜、晒干和青贮黑麦草在不同营养成分上各有优势,但3种牧草主要营养物质的表观消化率和代谢能值无显著差异。因此,无论是新鲜、晒干还是青贮黑麦草都可以作为反刍动物粗饲料的良好来源。

The aim of the trial was to evaluate the nutritional value of different types of ryegrass in vitro and in vivo.Twelve sheep with an average body weight of 66.87±2.34 kg were randomly divided into 3 groups with 4 replicates per group and 1 sheep per replicate.Sheep in three groups were fed fresh,silage and sun-dried ryegrass respectively.After a 14-day feeding experiment,feces and forage samples were collected for subsequent analysis.RESULTS:The contents of dry matter,organic matter and nitrogen-free extract in sun-dried ryegrass were the highest(P<0.05).The crude protein and hemicellulose contents of fresh ryegrass were significantly increased by 42.10%and 10.82%compared with those of silage ryegrass(P<0.05).The contents of crude fat,crude fiber,neutral detergent fiber and acid detergent fiber in silage ryegrass were significantly higher than those in the other two types of ryegrass(P<0.05).There were no significant differences in apparent digestibility of crude protein,ether extract and crude fiber among fresh,silage and sun-dried ryegrass(P>0.05).The apparent digestibility of dry matter of sun-dried ryegrass was significantly increased by 6.34%and 6.21%compared with that of fresh and silage ryegrass(P<0.05),the apparent digestibility of organic matter of sun-dried ryegrass was significantly increased by 6.65%compared with that of fresh ryegrass(P<0.05),and the apparent digestibility of nitrogen free extract was significantly increased by 15.44%compared with that of silage ryegrass(P<0.05).When the in vitro metabolism can value expressed in MJ/kg organic,fresh and silage ryegrass metabolism can value the dried ryegrass significantly increased by 21.34%and 22.41%respectively(P<0.05),while in vitro metabolic energy values expressed in MJ/kg of dry matter,fresh ryegrass can value the highest performance,silage ryegrass can value times,dry perennial ryegrass can value the lowest(P<0.05).Conclusions:Fresh ryegrass,sun-dried ryegrass and silage ryegrass have advantages in different nutrients,but there are no significant differences in the apparent digestibility and metabolizable energy values of main nutrients among the three forages.Therefore,whether fresh,sun-dried or silage ryegrass can be a good source of rouge forage for ruminants.