益生肠球菌应用于断奶仔猪的研究进展

仔猪早期断奶腹泻是困扰养猪业的严重问题,随着饲用抗生素作为饲料添加剂的禁止使用,寻求能够替代抗生素的新的生长促进剂成为研究的热点。益生肠球菌主要应用于医疗保健行业,研究主要集中在粪肠球菌(Enterococcus faecalis)和屎肠球菌(Enterococcus faecium),有关益生肠球菌作为饲料添加剂在动物饲料中的应用也逐渐引起了人们的关注,对其作用机制及有效包被技术的研究已取得了一些进展。通过介绍益生肠球菌在动物饲养,尤其是断奶仔猪中的应用现状和存在问题,以亟为该领域的研究提供参考。     

植物源农药印楝素微胶囊化工艺及防虫效果

该试验采用界面聚合法,对植物源农药印楝素进行微胶囊化,并通过正交试验优化微胶囊制备的工艺条件,旨在提高印楝素的稳定性,延长其田间防虫持效期.结果表明:壁材采用3∶4(m∶m)的甲苯-2,4-二异氰酸酯(TDD与六亚甲基四胺,芯材与壁材的配比为30∶7(m∶m),溶剂采用3∶2(m∶m)的乙酸乙酯和二甲苯混合溶剂比效适宜,微胶囊中印楝素的包埋率为(83.16±1.22)%.所制得的印楝素微胶囊剂通过盆栽试验表明,对昆虫具有较好的防治效果和较长的持效期.     

Temporal synergism can enhance carbamate and neonicotinoid insecticidal activity against resistant crop pests

BACKGROUND: Piperonyl butoxide (PBO) effectively synergises synthetic pyrethroids, rendering even very resistant insect pests susceptible, provided a temporal element is included between exposure to synergist and insecticide. This concept is now applied to carbamates and neonicotinoids. RESULTS: A microencapsulated formulation of PBO and pirimicarb reduced the resistance factor in a clone of Myzus persicae (Sulzer) from >19 000- to 100-fold and in Aphis gossypii (Glover) from >48 000- to 30-fold. Similar results were obtained for a strain of Bemisia tabaci Gennadius resistant to imidacloprid and acetamiprid, although a second resistant strain did not exhibit such a dramatic reduction, presumably owing to the presence of target-site insensitivity and the absence of metabolic resistance. Synergism was also observed in laboratory susceptible insects, suggesting that, even when detoxification is not enhanced, there is degradation of insecticides by the background enzymes. Use of an analogue of PBO, which inhibits esterases but has reduced potency against microsomal oxidases, suggests that acetamiprid resistance in whiteflies is largely oxidase based. CONCLUSION: Temporal synergism can effectively enhance the activity of carbamates and neonicotinoids against resistant insect pests. Although the extent of this enhancement is dependent upon the resistance mechanisms present, inhibition of background enzymes can confer increased sensitivity against target-site resistance as well as increased metabolism. .     

喷雾干燥法制备微胶囊化水产开口料

试验以明胶为壁材,采用乳化喷雾干燥法制备了在水中稳定性良好的微米级微胶囊化水产开口料微胶囊。考察了总固形物含量、芯壁材比、进料速度、进风温度对微胶囊粒径以及在水中稳定性的影响,并通过L9(34)正交试验优化了微胶囊化工艺。优化的工艺条件为:芯壁材比5∶1,总固形物含量15%,进料速度17.75mL/min,进风温度150℃。