饲料酵母的开发与应用

饲料酵母是利用工业废渣等生产的一种蛋白质饲料,其蛋白质含量为45～60％,各种必需氨基酸齐     

Effects of Yeast Culture on Growth Performance,Meat Quality and Intestinal Microflora of Broilers

The experiment was conducted to study the effects of yeast culture on growth performance, meat quality and intestinal microflora of broilers. A total of 432 1-day-old AA commercial broiler chicks with initial body weight of (41.73±0.15)g were randomly divided into 4 groups with 6 replicates per group and 18 broilers per replicate,receiving diets supplemented with 0,0.1%,0.2% and 0.3% yeast culture, respectively. The trial lasted for 42 days which was divided into two periods with 1 to 21 d and 22 to 42 d,respectively.The feed intake,body weight,death and culling rate were recorded in each period. At the end of the experiment,1 chickens in each replicate with the weight close to the average value were slaughtered after fasting for 12 h. The slaughter performance and intestinal microflora counts were determined.The results showed that compared with control group,the supplementation of 0.2% and 0.3% yeast culture significantly increased the body weight at 42 d and the average daily gain (ADG) during the whole trial (P< 0.05).The diet supplemented with 0.2% yeast culture significantly improved the ADG,decreased the F/G of broilers during 22 to 42 d (P< 0.05),and it also significantly increased the average daily feed intake (ADFI) and ADG (P< 0.05),decreased the F/G of the whole period (P< 0.05).Moreover,the supplementation of 0.2% yeast culture significantly decreased the drip loss of meat and the count of Escherichia coli (P< 0.05),and significantly increased the count of Bifidobacterium(P< 0.05). In summary, the supplementation of 0.2% yeast culture could significantly improve the growth performance and the muscle quality of broilers.The intestinal microflora in broiler cecum were effectively optimized after inclusion of yeast culture in the study.     

细菌表达 dsRNA 介导桔小实蝇 flightin基因的 RNA 干扰

【目的】探索饲喂细菌表达目标基因dsRNA介导桔小实蝇flightin基因RNAi的可行性。【方法】将桔小实蝇flightin基因的相应干扰片段构建至L4440干扰载体,并转化大肠杆菌HT115(DE3)菌株,利用IPTG诱导表达flightin基因对应的dsRNA,命名为flightin-dsRNA。【结果】通过饲喂表达flightin-dsRNA的大肠杆菌10倍浓缩菌液,桔小实蝇flightin基因的表达普遍出现了不同程度的上调,其中,雌虫饲喂后5、10、20 d,雄虫饲喂后5 d与对照差异显著,雄虫饲喂后15 d诱发约43%的下调;该方法对桔小实蝇飞行能力及胸部肌肉发育未产生明显影响。【结论】通过饲喂表达flightin-dsRNA的大肠杆菌对桔小实蝇flightin基因进行RNA干扰不可行或干扰效果不明显。     

酵母硒抗氧化作用及其对肥育猪肉品质影响的研究进展

猪肉消费在我国居民的肉类消费中占主导地位,随着生活水平的提高,消费者对猪肉品质提出更高的要求。研究发现,猪肉品质受遗传、营养、饲养管理和环境等因素影响,常用肉色、pH值、肌内脂肪、滴水损失、嫩度和风味等指标表示。氧化应激是影响猪肉品质的主要因素。硒是谷胱甘肽过氧化物酶的重要组成部分,可以通过催化减少有机氢过氧化物生成量而抵抗氧化应激。许多研究表明,在肥育猪日粮中添加酵母硒能有效改善肥育猪肉的抗氧化能力,改善肥育猪的肉色、pH值及系水力等指标,提高肥育猪的肉品质,延长了猪肉货架期。因此综述了酵母硒的抗氧化机理以及对肥育猪肉品质指标的影响,以期为改善肉质的营养措施提供科学依据。     

以酒糟代替鱼粉生产高蛋白鱼饲

日本千叶县水产联合体利用粮食酿酒以后的下脚料酒糟渣，加入1．5％-2．0％的鲜（干）酵母发酵后培养，再经过脱水、干燥、磨粉、制粒，生产出一种发酵高蛋白颗粒鱼饲料。与传统的直接将酒糟用作饲料原料相比，使用这种饲料，氨基酸的可利用率从8，8％提高到19，5％-22．5％，能量从原来的每千克10．504mJ提高到17．786mJ，     

酵母表达典型猪瘟E2亚单位疫苗对致死量攻毒提供保护

典型猪瘟（CSF）由典型猪瘟病毒（CSFV）引起，是一个高度传染的猪病，给猪业生产造成巨大的经济损失。病毒衣壳糖蛋白E（ms）和E2是感染该病毒后诱导产生CSFV抗体的主要靶向目标。毕赤酵母表达E2蛋白（yE2）可产生免疫保护．对抗CSFV攻毒。     

两种复合肉质改进剂对猪组织硒含量和肉品质的影响

为评价以酵母硒和茶多酚为主配伍的1号和2号复合肉质改进剂的效果，试验选择108头80．26±3．11kg社长大肥育猪，采用完全随机设计，分成3个处理，每个处理3个重复（栏），每栏12头猪。分别饲喂基础日粮和在基础日粮中添加500g／t的1号和2号复合肉质改进剂。正试期30d，前腔静脉采血后，每栏选2头猪屠宰取背最长肌，测定猪肉品质及组织硒含量。结果表明：添加肉质改进荆可显著提高猪肉宰杀45min以内的pH。值4．65％-6．02％（P〈0．05），显著降低宰杀24h后的滴水损失24．39％～44．57％（P〈0．05），对改善猪肉颜色和肌内脂肪有一定的作用（P〉0.1）；显著提高血清硒含量9．9％和肝脏硒含量84．8％～88．9％（P〈0．05）。试验结果表明在日粮中添加500g／t的1号复合肉质改进剂对猪肉品质和组织硒含量有明显的改善作用。     

酵母培养物对绵羊瘤胃发酵及生产性能的影响

本研究用酵母(JM)菌种,采取菌种液体培养-固体发酵的方法制备酵母培养物,活菌数达到3×109个/g.进行了酵母培养物对放牧补饲绵羊瘤胃发酵及生产性能影响的对比试验,按10g/d*只添加,连续饲喂30 d,提高日增重11.1%(P＞0.05).显著降低饲喂后瘤胃内氨态氮的含量(P<0.05).促进挥发性脂肪酸的生成,提高总挥发性脂肪酸量和乙酸/丙酸比值.提高饲喂后原虫数.稳定瘤胃pH.