نوع مقاله : مقالات علمی- پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران.
2 گروه علوم دامی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
An experiment was conducted to evaluate the effect of early feed restriction on performance and serum thyroxin
concentration of broiler chicks. The experiment was designed in a 2×2 factorial with 5 replicates of floor pens with 12 male
or female chicks in each. 240 male and/or female day-old chicks of a commercial strain (Hybrow) were wing banded,
weighed and randomly allocated to two treatment groups of each sex. Two treatments involved, one control group (no
restriction) and one restricted group, which were fed a mixture of 50:50 rice hulls and commercial starter diet with
supplementation of trace minerals & vitamin premixes from 4 to 11 days of age. All groups were fed the same starter, grower
& finisher diets from 11 to 56 days of age. Live body weight (LBW) of restricted birds was compensated on day 42 of age
and was greater than restricted group at 49 and 56 days of age. Mean daily feed intake and feed conversion ratio up to 42, 49
and 56 days of age wasn't affected significantly by treatments. Feed cost per kg of LBW in Restricted birds markedly
improved in compare to control group. Furthermore, feed cost per kg of LBW for male chicks was lower than of female
chicks. Carcass fat content of restricted birds was significantly lower than of control birds. Also, carcass fat content of male
chicks was significantly lower than of female chicks. Abdominal fat of restricted birds at 49 and 56 days of age was
significantly lower than of control birds. Mean LBW up to 42, 49 and 56 days of age, weight gain and feed intake for male
chicks was more than female chicks. Serum thyroxin concentration on day 11 in restricted group was significantly lower than
control group but its concentration during accelerated growth period (28-49 days of age) in restricted group was
nonsignificantly more than control group. Results of this experiment showed that, broiler chickens after early feed restriction
compensated the retarded growth and showed less abdominal and carcass fat content.
کلیدواژه‌ها [English]
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