Gregory P C, Wenham G, Poppi D, Coop R L, MacRae J C, Miller S J
Parasitology. 1985 Oct;91 ( Pt 2):381-96. doi: 10.1017/s0031182000057449.
The influence of a chronic subclinical infection of Trichostrongylus colubriformis, 2500 larvae/day for 12 weeks, on gastrointestinal motility and digesta flow was studied in 12 sheep supplied ad libitum with food and water. Motility was recorded by X-radiography and electromyography from chronically implanted electrodes; abomasal volume and outflow were estimated by dilution of CrEDTA; small intestinal transit time was estimated by passage of Phenol Red. The findings were compared with measurements made prior to infection at restricted food intake and reported separately. The first effects of infection were seen after 3-4 weeks. No animal developed diarrhoea, but food intake was progressively reduced. Small intestinal transit time, abomasal volume and half-time of marker dilution increased while abomasal outflow decreased during infection. These changes occurred both in absolute terms and when compared with values predicted from the observed level of food intake. As the animals became resistant to the parasites abomasal volume and digesta flow returned towards control values (weeks 10-12). The migrating myoelectric complex (MMC) was disrupted in only one sheep, and only transiently. In all sheep the frequency of the MMC was increased during infection and there was a progressive inhibition of abomasal, duodenal and jejunal motility. X-radiography showed there was prolonged pooling of digesta in the proximal small intestine which was cleared only at the phase of regular spiking activity. Two sheep given an anthelmintic drench recovered normal motility and clearance of digesta. It is concluded that subclinical infection of sheep with T. colubriformis alters the normal pattern of gastrointestinal motility in the absence of any diarrhoea, and causes inhibition of abomasal and proximal small intestinal motility and digesta flow. The increased frequency of MMCs helps to maintain digesta flow through the proximal small intestine.
在12只随意采食和饮水的绵羊中，研究了连续12周每天感染2500条蛇形毛圆线虫幼虫的慢性亚临床感染对胃肠动力和食糜流动的影响。通过X射线摄影和慢性植入电极的肌电图记录动力；通过CrEDTA稀释估计皱胃体积和流出量；通过酚红的通过估计小肠转运时间。将这些结果与感染前在限制食物摄入量时进行的测量结果进行比较，并分别报告。感染的最初影响在3 - 4周后出现。没有动物出现腹泻，但采食量逐渐减少。感染期间，小肠转运时间、皱胃体积和标记物稀释半衰期增加，而皱胃流出量减少。这些变化无论是绝对值还是与根据观察到的采食量水平预测的值相比都存在。随着动物对寄生虫产生抗性，皱胃体积和食糜流动恢复到对照值（第10 - 12周）。仅在一只绵羊中迁移性肌电复合波（MMC）受到干扰，且只是短暂的。在所有绵羊中，感染期间MMC的频率增加，皱胃、十二指肠和空肠动力逐渐受到抑制。X射线摄影显示，食糜在近端小肠中长时间积聚，仅在规则的尖峰活动阶段才被清除。两只接受驱虫药灌服的绵羊恢复了正常的动力和食糜清除。结论是，绵羊感染蛇形毛圆线虫的亚临床感染在没有任何腹泻的情况下改变了胃肠动力的正常模式，并导致皱胃和近端小肠动力及食糜流动受到抑制。MMC频率的增加有助于维持食糜通过近端小肠的流动。
