Kommuru D S, Whitley N C, Miller J E, Mosjidis J A, Burke J M, Gujja S, Mechineni A, Terrill T H
Fort Valley State University, Fort Valley, GA 31030, USA.
North Carolina Agricultural and Technical State University, Greensboro, NC 27420, USA.
Vet Parasitol. 2015 Jan 15;207(1-2):170-5. doi: 10.1016/j.vetpar.2014.11.008. Epub 2014 Nov 15.
Sericea lespedeza (SL; Lespedeza cuneata) is a perennial warm-season forage rich in condensed tannins (CT) that has been reported to have anthelmintic activity against small ruminant gastrointestinal nematodes (GIN), particularly Haemonchus contortus, a highly pathogenic blood-feeder, but the mechanism of action of CT against H. contortus is not clearly understood. An experiment with young goats was designed to study the effect of SL leaf meal pellets on (1) a mature H. contortus infection, and (2) the surface appearance of adult H. contortus female worms. Thirty-six female and castrated male Boer crossbred goats artificially infected with H. contortus larvae were fed 75% SL leaf meal pellets or alfalfa pellets (18 goats/treatment group) in a 28-day confinement feeding trial. Fecal and blood samples were collected weekly for fecal egg count (FEC) and packed cell volume (PCV) determination, respectively, and all goats were slaughtered at the end of the trial for adult GIN recovery and counting. Five adult female H. contortus were recovered from the abomasum of two goats from each treatment group and from a prior study in which 75% and 95% SL leaf meal pellets or a commercial feed pellet were group-fed to grazing goats (270 days old, Spanish males, 10/treatment group) at 0.91 kg/head/d for 11 weeks. Adult GIN collected were fixed and examined for evidence of surface damage using scanning electron microscopy. Feeding 75% SL pellets to young goats in confinement reduced (P<0.05) FEC compared with control animals, while total worm numbers and PCV were not influenced by treatment. Three out of the 5 adult H. contortus recovered from SL treatment goats in the confinement feeding trial had cuticular surface damage, while no damage was observed on worms from the control group. All five worms observed from both SL treatments in the grazing study showed a shrunken, disheveled cuticular surface, whereas this was not observed on worms from control animals. Overall, this work suggests that a possible mechanism of action of SL against female H. contortus in the animal's abomasum is a direct action of CT on the cuticle of the worm.
绢毛胡枝子（SL；Lespedeza cuneata）是一种富含缩合单宁（CT）的多年生暖季型牧草，据报道它对小型反刍动物胃肠道线虫（GIN）具有驱虫活性，尤其是对捻转血矛线虫这种高致病性吸血线虫，但CT对捻转血矛线虫的作用机制尚不清楚。设计了一项针对幼山羊的实验，以研究SL叶粉颗粒对（1）成熟捻转血矛线虫感染，以及（2）成年捻转血矛线虫雌虫体表外观的影响。在一项为期28天的圈养饲喂试验中，将36只人工感染捻转血矛线虫幼虫的雌性和去势雄性波尔杂交山羊分为两组，分别饲喂75%的SL叶粉颗粒或苜蓿颗粒（每组18只山羊）。每周分别采集粪便和血液样本，用于测定粪便虫卵计数（FEC）和血细胞压积（PCV），试验结束时宰杀所有山羊，以回收和计数成年胃肠道线虫。从每个处理组的两只山羊的皱胃中回收了5只成年雌性捻转血矛线虫，并从之前的一项研究中回收了一些线虫，在该研究中，将75%和95%的SL叶粉颗粒或商业饲料颗粒以0.91 kg/头/天的量分组饲喂给放牧山羊（270日龄，西班牙雄性，每组10只），持续11周。将回收的成年胃肠道线虫固定，并用扫描电子显微镜检查体表损伤情况。在圈养条件下，给幼山羊饲喂75%的SL颗粒，与对照动物相比，粪便虫卵计数（FEC）降低（P<0.05），而虫体总数和血细胞压积不受处理影响。在圈养饲喂试验中，从接受SL处理的山羊中回收的5只成年捻转血矛线虫中有3只体表有损伤，而对照组的线虫未观察到损伤。在放牧研究中，从两种SL处理中观察到的所有5只线虫的体表均出现萎缩、凌乱，而对照动物的线虫未观察到这种情况。总体而言，这项研究表明，SL对动物皱胃中雌性捻转血矛线虫的一种可能作用机制是CT对虫体角质层的直接作用。
