Artemisia annua as phytogenic feed additive in the diet of broilers (14-35 days) reared under heat stress (32 ºC)

Abstract

The 21 days feeding trial was conducted on 90, Cobb 500 broilers (aged 14 days), assigned to 3 groups (C, E1 and E2) housed in an experimental hall at 32° C constant temperature and 23 h light regimen. During the growth period (14-35 days), the conventional diet (C) had corn and soybean meal as basic ingredients. Unlike the conventional diet formulation (C), the diet formulations for the experimental groups also included 0.005% Artemisia annua oil (E1) and 0.005% Artemisia annua oil plus 1% Artemisia annua powder (E2). Six broilers per group were slaughtered at 35 days of age in order to measure the weight of the carcass and internal organs of broilers, and samples of intestinal and caecal content were collected for bacteriological assessment (Enterobacteriaceae, E. coli, staphylococci, Lactobacilli, Salmonella spp.).The following parameters were monitored during the experimental period: bodyweight (g); average daily feed intake (g feed/broiler/day); average daily weight gain (g/broiler/day); feed conversion ratio (g feed/g gain). Under heat stress (32 ºC), E2 broilers (mixture of A. annua oil and powder) had a significantly (p<0.05) higher average of daily feed intake than the broilers receiving the C diet or the diet supplemented just with A. annua oil (E1). Both samples of intestinal and caecal content, showed the lowest count (p<0.05) of Enterobacteriaceae, E. coli and staphylococcus colony forming units in E2 broilers. Diet with A. annua oil and powder provided proper conditions for lactic acid bacteria proliferation in the intestine and caecum of heat stressed broilers.