Mitigation of effects from heat stress by Artemisia species

Abstract

Artemisia afra (AF) is a herb used by indigenous peoples of South Africa to alleviate heat stress during desert travel, and Artemisia absinthium (AB) is a related plant grown in the U. S. Two experiments were conducted to evaluate the effects of AF and/or AB on metabolic rate and activity in mice, and semen quality in boars. Male mice (n = 49) were housed in a neutral environment (21°C) and given ad libitum access to a 1% w/v decoction of AF, AB, or tap water (TW). Mice were then exposed to a heat stress environment (35°C) for 5 days. Metabolic rate was calculated based on O2 consumption, CO2 production and respiratory exchange ratio collected in individual indirect calorimeters. Metabolic rate was higher (P = 0.06) in AB overall. Both AB and AF had a higher (P = 0.001) tail temperature than TW during the heat stress period. No difference was seen in activity. Subsequently, six 8-mo old boars were assigned in a crossover design to be given a decoction of AB or TW before and during a 5-d period in a heat stress (32°C) chamber. Boars were collected for 5-wk following the initiation of heat stress. Boars given AB (1400 hr) had a lower ear temperature (P=0.02) than those given TW (1400 hr). Boars given TW (1400 hr) had a higher shoulder temperature (P=0.04) than TW (400 h). Liquid consumption of TW was higher than AB (P=0.003). Semen quality measurements showed a significant difference within a week following heat stress, but there was no difference between treatments.