Datta F U, Nolan J V, Rowe J B, Gray G D, Crook B J
Division of Animal Science, UNE Armidale, NSW, Australia.
Int J Parasitol. 1999 Mar;29(3):479-88. doi: 10.1016/s0020-7519(98)00209-4.
Weaner sheep that had been hand-fed on diets containing increasing concentrations of protein for a 9-week period (when uninfected, or infected with Haemonchus contortus) were studied during the next 69 weeks when put on to pasture as a single, unsupplemented flock. During the 9-week period, groups of 12 sheep (six infected, six uninfected) were offered one of five iso-energetic (9.0 MJ kg(-1)) diets containing 10, 13, 16, 19 or 22% crude protein. All sheep were treated with anthelmintic at the end of the 9 weeks and then put out to pasture for 69 weeks, where they were all subject to the same environmental variables including nematode larval challenge. During the grazing period, animals that had previously received the higher protein diets consistently had higher live-weight gain and wool production, higher antibody responses to both H. contortus and Trichostrongylus colubriformis antigenic challenge in vitro, and lower faecal nematode egg counts than did the lambs previously offered the lower protein diets. Faecal egg counts of the grazing sheep that had been artificially infected with H. contortus while being hand-fed were similar to those of the uninfected sheep and there was no interaction between previous infection and dietary protein concentration. We conclude that short periods of enhanced post-weaning nutrition can have long-term and perhaps life-long effects on production.
断奶羔羊在9周内（未感染或感染捻转血矛线虫时）人工饲喂含蛋白质浓度递增的日粮，之后作为一个未补充饲料的单一羊群被放归牧场69周进行研究。在这9周期间，将12只羊分为一组（6只感染，6只未感染），分别饲喂5种等能量（9.0 MJ kg(-1)）日粮之一，日粮粗蛋白含量分别为10%、13%、16%、19%或22%。9周结束时，所有羊都接受了驱虫处理，然后放归牧场69周，在那里它们都面临相同的环境变量，包括线虫幼虫的挑战。在放牧期间，之前接受高蛋白日粮的动物体重增加和羊毛产量一直较高，对捻转血矛线虫和哥伦比亚细颈线虫抗原体外攻击的抗体反应更强，粪便中线虫卵计数低于之前接受低蛋白日粮的羔羊。在人工饲喂期间人工感染捻转血矛线虫的放牧羊的粪便虫卵计数与未感染羊相似，之前的感染与日粮蛋白质浓度之间没有相互作用。我们得出结论，断奶后短期营养强化可能对生产产生长期甚至终生的影响。
