Investigation on the effects of feeding timetable on estradiol, progesterone, triiodothyronine and tetraiodothyronine in broiler breeder flocks

摘要

This experiment was performed in order to study of the effect of the timetable, amount and frequency of feeding on hormonal metabolites of broiler breeder. Experiment was conducted in a completely randomized design with 15 treatments for 1, 2, 3 and 4 times a day feeding with 4 replications. The nutritional composition of all experimental groups was similar. The 1st treatment involves once feeding per day (4 am with 100% of the diet), the 2nd treatment includes feeding twice per day (4 am and 16 pm as much as 50% of the total diet per each time), the 3rd treatment including feeding twice per day (4 am and 16 pm as much as 75 and 25% of the total diet respectively), the 4th treatment consisted of feeding twice per day (4 am and 12 am as much as 50% of the total diet respectively), the 5th treatment consisted of feeding twice per day (4 am and 12 am as much as 75 and 25% of the total diet respectively), 6th treatment includes feeding twice per day (6 am and 16 pm as much as 75 and 25% of the total diet respectively), 7th treatment including feeding twice a day (6 am and 16 pm per 50% of the total diet respectively), 8th treatments fed 3 times per day (4 am, 12 am, and 16 pm as much as 50, 25 and 25% of the total diet respectively), 9th treatment fed 3 times per day (4 am, 12 am, and 16 pm as much as 33% of the total diet respectively), 10th treatments include eating 3 times per day (4 am, 12 am, and 16 pm as much as 25, 50 and 25% of the total diet respectively), 11th treatment fed 3 times per day (4 am, 12 am, and 16 pm, as much as 25, 25 and 50% of the total diet respectively), 12nd treatment included 3 feeding per day (4 am, 12 am, and 16 pm, as much as 50, 25 and 25% of the total diet respectively), 13rd treatment included fed 3 times per day (4 am hours, 12 am, and 16 pm as much as 33% of the total diet respectively), 14th treatment fed 4 times per day (4 am, 12 am, and 16 pm per 33, 22, 22 and 22% of total diet), 15 treatments consists of 4 feeding per day (4 am, 8 am,12 am, and 16 pm as much as 50, 17, 17 and 17% of the total diet, respectively). Hormonal parameters were measured in chickens at 31st and 36th weeks of age. The statistical results of this experiment show plasma hormone concentrations at the age of 31 weeks in treatment with more than one feeding per day was significantly different from controls (P0.05). The concentration of T3, T4, progesterone and estradiol at the age of 31 weeks with diet changes more than once a day showed a decreasing trend.