الخلاصة:
This study was conducted to investigate the effects of different crude protein
(CP) feeding strategies on the growth performance, food intake and visceral
organs weights of Awassi lambs during fattening. Forty eight weaned male
Awassi lambs were randomly divided in 4 equal groups according to the diet
regimen: whereas the CP content remained constant during the whole 16
week fattening period in diets distributed to the first 3 groups, 12%, 16%
and 18% respectively, it was gradually and monthly decreased from 20% to
14% in the diet distributed to the 4th lamb group. The body weight gains and
the food intakes in lambs fed with the decreasing CP content diet compared
to the other groups were markedly and significantly increased since the 8th
week and the 5th week respectively, although these 2 parameters were moderately
delayed around the 12th week until the end of the experimental fattening
period in all lambs. In addition, the food efficiency was significantly
enhanced in animals receiving diets with the decreasing CP content or high
protein content (18%). The hot and chilled carcass weights as well as the
visceral organ (lungs, kidneys and liver) relative weights were also more elevated
in these 2 groups while the kidney fat proportions were significantly
decreased. These results show that a gradual decrease in the dietary protein
content (from 20% to 14%) during fattening markedly improves the growth
performance and the visceral organ mass in lambs, leading to an important
reduction in the meat production cost.
