Do capybaras enhance their resistance to parasites under nutritional stress?

EBERHARDT A. T.; MANZOLI, D.E.; FERNANDEZ, C.; TORRENTS, J.; IGLESIAS, C.; BELDOMENICO, P.M.

Congreso; 100TH ANNUAL MEETING OF THE AMERICAN SOCIETY OF MAMMALOGISTS; 2021

American Society of Mammalogist

Against infection, hosts engage in two distinct defense strategies, tolerance and resistance. Resisting involves decreasing parasite fitness (survival and/or output). Resistance mechanisms could be energetically costly and thus it is expected that such expenditure could be afforded fully by hosts in good condition. To evaluate the effect of nutritional stress on parasite burdens and output to specific nematodes (count of adult and mean number of eggs/female) and coccidians (number of oocysts/gram of faeces) in capybara we conducted an experiment under controlled conditions using 24 wild-caught young females. Animals dewormed and randomly allocated into two groups: control (fed ad libitum) and food-restricted (40% of the food quantity consumed by control group) for 15 weeks. After 10 weeks, capybaras were inoculated with two kinds of parasites: Eimeria spp., Vianella hydrochoeri and Strongyloides chapini. There were no significant difference between treatment groups in oocytes shedding after the inoculation (first peak). However, in the following weeks, food-restricted capybaras tended to shed less oocyts than controls. While counts of nematodes did not differ among treatment groups, S. chapini females in capybaras of food-restriction groups laid fewer eggs than females in control groups. Our results suggest that under nutritional stress capybaras enhance their resistance, reducing the output of both nematodes and coccidians.