Material and methods
2.1. Animals and diets
The experiment was carried out at the experimental
farm of the National Institute of Agricultural Research of
Tunisia (INRAT). 32 male Barbarine lambs were used; they
had an average body weight (BW) of 19.9±2.15 kg. They
were divided into 2 homogeneous groups according to BW,
animals were fed in individual boxes a ration based on
50% dried alfalfa and 50% concentrate. 2 types of concentrate
were used; Control (C) concentrate was composed
of barley (80%), soybean meal (18%) and mineral vitamin
supplement (2%) and the experimental concentrate corresponds
to the C one with 0.06% of rosemary essential oils
(RE). Food was distributed 2 times a day (9 h and 15 h). Animals
of all groups had free access to water. At the end of the
growth trial (60 days), all animals were slaughtered. Their
final body weight before slaughtering was 25±3 kg.