Lisonbee Larry D, Villalba Juan J, Provenza Fred D, Hall Jeffery O
Department of Wildland Resources, Utah State University, Logan, UT 84322, USA.
Behav Processes. 2009 Oct;82(2):184-9. doi: 10.1016/j.beproc.2009.06.009. Epub 2009 Jul 2.
Animals adapt to the variability of the external environment and to their changing internal needs not only by generating homeostatic physiological responses, but also by operating in the external environment. In this study, we determined whether sheep with a gastrointestinal parasite infection increased intake of a low-quality food containing a natural antiparasitic agent (tannins) relative to non-parasitized sheep. Four groups of lambs (n=8 lambs/group) were assigned to a 2 x 2 factorial design with parasitic burden (P=parasites; NP=no parasites) and the offer of a supplement containing tannins (yes, no) as the main factors. Parasitized lambs ate more of the tannin-containing food than non-parasitized lambs for the first 12 days of the study, when parasite burdens were high, but differences became smaller and disappeared toward the end of the study when parasite burdens decreased. This result suggests the lambs detected the presence of internal parasites or associated symptoms and modified their ingestion of an antiparasitic agent as a function of need.
动物不仅通过产生稳态生理反应，还通过在外部环境中活动来适应外部环境的变化以及自身不断变化的内部需求。在本研究中，我们确定感染胃肠道寄生虫的绵羊相对于未感染寄生虫的绵羊，是否会增加对含有天然抗寄生虫剂（单宁）的低质量食物的摄入量。四组羔羊（每组n = 8只羔羊）被分配到一个2×2析因设计中，主要因素为寄生虫负荷（P = 寄生虫感染；NP = 未感染寄生虫）和是否提供含单宁的补充剂（是、否）。在研究的前12天，当寄生虫负荷较高时，感染寄生虫的羔羊比未感染寄生虫的羔羊摄入了更多含单宁的食物，但在研究结束时，当寄生虫负荷降低时，差异变小并消失。这一结果表明，羔羊检测到体内寄生虫的存在或相关症状，并根据需要调整了对抗寄生虫剂的摄入量。
