饲用甜高粱青绿饲喂肉羊技术及其效应

Feeding technology and effect on fattening sheep with green forage sweet sorghum

【目的】探究甜高粱作为青绿饲料舍饲饲喂肉羊效应及安全饲喂技术,为其安全高效用于草食畜生产提供科学实证。【方法】试验选取12只2~3月龄健康小尾寒羊(15.0±0.2 kg;♂)作为供试动物。饲养试验为期105 d,分为2个阶段,第一阶段(试验的1~20 d)仅饲喂甜高粱青绿饲草,第二阶段(试验的21~105 d)饲喂甜高粱青绿饲草、甜高粱青贮(自由采食)和精料(定量投喂)。于第一阶段(试验开始后的第20天)和第二阶段(试验开始的第50天)分别对相同的4只试验羊采集血液和瘤胃液,测定瘤胃液pH,利用高通量技术分析瘤胃微生物多样性,并进行了血液生理指标的测定;试验的第105天对试验羊进行屠宰试验并检测了7只试验羊的屠宰性能和肉品质。【结果】试验羊第一阶段死亡5只,平均日增质量(average daily weight gain,ADG)为负值(-72.11 g),第二阶段未出现死亡状况,平均日增质量为199.57 g,且试验羊的第二阶段的平均日采食量(1189.57 g,average daily feed dry matter intake,ADFI)高于第一阶段(440.00 g)。第一阶段和第二阶段的瘤胃液pH值、瘤胃微生物DNA序列的OTU数、Simpson指数和Chao1差异均不显著(P>0.05),而第一阶段的Shannon指数显著高于第二阶段(P<0.05)。在门水平上,第一阶段软壁菌门的相对丰度显著高于第二阶段(P<0.05);在属水平上第二阶段的琥珀酸菌属的相对丰度显著高于第一阶段(P<0.05),第一阶段的瘤胃球菌属和丁酸弧菌属的相对丰度显著高于第二阶段(P<0.05)。第一阶段的白细胞数目(white blood cell,WBC)显著低于第二阶段(P<0.05),第一阶段的平均红细胞体积(mean corpuscular volume,MCV)、平均红细胞血红蛋白含量(mean corpuscular hemoglobin,MCH)、平均红细胞血红蛋白浓度(mean corpuscular hemoglobin concentration,MCHC)和平均血小板体积(mean platelet volume,MPV)极显著高于第二阶段(P<0.001),第二阶段的红细胞数目(red blood cell,RBC)、红细胞压积(hematocrit cell,HCT)极显著高于第一阶段(P<0.001)。试验羊的宰前活质量为32.10 kg,屠宰率为48.24%,眼肌面积为13.70 cm^(2),GR值为20.92.4)试验羊肉的剪切力为8.55 kg/cm^(2),失水率为14.91%。【结论】在全舍饲条件下,单一的青绿甜高粱会使试验羊发生减重甚至死亡的现象,增加其患维生素B_(12)缺乏性贫血的几率,对其健康存在一定风险,青绿甜高粱和青贮饲料及精料混合饲喂会使其生长性能和屠宰性能恢复正常。

【Objective】To explore the effect of fresh sweet sorghum forage for fattening lambs and its safe feeding technology,and to provide scientific evidence for its efficient utilization in herbivores production.【Method】A total of 12,2~3 months old healthy small tailed Han male lambs(averaging 15.0±0.2 kg;♂of body weight)were fed at two different stages with two different diets for 105 days.At the first stage animals were fed with only fresh sweet sorghum forage,and at the second stage animals were fed with fresh sweet sorghum forage,sweet sorghum silage and concentrate supplements.At the end of the experiment,7 lambs were slaughtered and the slaughter performance and meat quality were examined.Blood samples and rumen fluid were collected from the same 4 lambs in the first stage(the 20 th day)and the second stage(the 50 th day),and the rumen fluid pH was examined,the rumen microbial diversity was analyzed by high-throughput technique;【Result】The average daily weight gain(ADG)of the lambs at the first stage of the experiment was negative(-72.11 g),but the ADG at the second stage was 199.57 g,and the average daily dry matter intake at the second stage(1.12 kg)was higher than at the first stage(0.44 kg).The rumen fluid pH,OTU number,Simpson index and Chao1 of the rumen microbial DNA sequences in the first and second stages were not significantly different(P>0.05),while the Shannon index was higher at the first stage than at the second stage(P<0.05).At the phylum level,the relative abundance of the Tenericutes at the first stage was significantly higher than that of the second stage(P<0.05);At the genus level,the relative abundance of the Succiniclasticum at the second stage was higher than that of the first stage(P<0.05).The relative abundance of the Ruminococcus and Butyrivibrio at the first stage was higher than that of the second stage(P<0.05).The white blood cell(WBC)were higher at the first stage than at the second stage(P<0.05).The mean corpuscular volume(MCV),mean corpuscular hemoglobin(MCH),mean corpuscular hemoglobin concentration(MCHC)and mean platelet volume(MPV)were higher in the second stage than at the first stage(P<0.001).The red blood cell(RBC)and hematocrit(HCT)in the second stage were higher than in the first stage(P<0.001).3)The pre-slaughter live weight of the lambs was 32.10 kg,the dressing percentage was 48.24%,the lion-eye area was 13.70 cm^(2),and the GR value was 20.92.The mutton shear force was 8.55 kg/cm^(2),and the water loss rate was 14.91%.【Conclusion】Under the fully indoor feeding condition,the single fresh sweet sorghum diet for fattening lambs will result in the deficiency of vitamin B_(12) and at the risk of anemia and finally death of the experimental animals,while the diets added to sweet sorghum silage and concentrate supplements can restore lambs growth and improve slaughter performance.