Effect of agarwood leaf extract on production performance of broilers experiencing heat stress

BACKGROUND AND AIM: The open house cage is mainly influenced by the environmental heat from the sun and the heat released by the chicken. Heat stress can affect physiological conditions so that it has an impact on decreasing productivity. This study aims to determine the effect of agarwood leaf extract in feed on the physiological condition and production performance of broilers experiencing heat stress and to generate prediction equations for the optimal level of the extract in feed. MATERIALS AND METHODS: A total of 200 22-day-old broilers (Cobb 500™) underwent four treatments with five replications each, namely, feed without agarwood leaf extract (control) (T0), and feed with 250 (T1), 300 (T2), and 350 mg of agarwood leaf extract/kg body weight (T3). The parameters observed include physiological condition (heart rate, respiratory frequency, and body temperature) as well as production performance (feed consumption, body weight gain [BWG], and feed conversion). RESULTS: The administration of agarwood leaf extract significantly (p<0.05) decreased heart rate and respiratory frequency. However, there was no significant difference (p>0.05) in body temperature, glucose levels, hemoglobin and erythrocyte concentrations, as well as production performance which include weight gain, feed consumption, and feed conversion ratio. Meanwhile, broilers treated with agarwood leaf extract had a significantly lower heart rate and respiratory frequency (p<0.05) compared to the control. However, broilers given agarwood leaf extract showed better body weight, consumption, and ration conversion compared to the control. CONCLUSION: Agarwood leaf extract in feed reduces heart rate and respiratory frequency but has no significant effect on body temperature and hematological parameters (glucose levels, hemoglobin, and erythrocyte concentrations) as well as production performance (feed consumption, weight gain, and feed conversion). These results indicate that the administration of 350 mg/kg body weight agarwood leaf extract is most effective to reduce feed consumption and increase BWG.