Hassan Shirzadi; Gholamreza Zaboli
Volume 21, Issue 4 , January 2020, , Pages 499-509
Abstract
The aim of this research is to estimate the methionine requirement of Japanese quails (Coturnix coturnix japonica) from 7 to 21 d of age using linear and quadratic broken-line regressions under chronic heat stress. A total of 480 quails were distributed according to a completely randomized ...
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The aim of this research is to estimate the methionine requirement of Japanese quails (Coturnix coturnix japonica) from 7 to 21 d of age using linear and quadratic broken-line regressions under chronic heat stress. A total of 480 quails were distributed according to a completely randomized design in 6 experimental treatments (diets containing 0.40, 0.45, 0.50, 0.55, 0.60 and 0.65% of methionine), with 4 replicates of 20 birds each. The basal diet was based on the corn-soybean meal and was formulated in mash form. Supplemental DL-methionine was added to the basal diet at the expense of corn starch to create experimental diets. The birds were fed a standard diet up to d 7, and then were weighed and randomly allotted to the experimental treatments. Birds exposed to chronic heat stress from 8 d of age for 6 h daily (37 ± 0.8°C from 10 AM to 16 AM). The optimal amounts of methionine for body weight gain, feed conversion ratio, and breast meat yield were obtained with 0.55, 0.57, and 0.60% of the diet as estimated by linear broken-line regression. However, based on the quadratic broken-line regression, the corresponding values were estimated at 0.58, 0.59, and 0.62% of the diet, respectively. According to the findings of this study, It seems that amounts of methionine higher than the usual recommendations are needed for Japanese quails to achieve optimal performance under chronic heat stress.
Behrouz Dastar; mohsen rajabzadeh nesvan; Mahmoud Shams Shargh; Mokhtar Mohajer
Volume 18, Issue 3 , October 2016, , Pages 553-562
Abstract
The effect of feeding different protein profiles on growth performance, carcass components and nitrogen content of litter in Cobb 500 broiler strain was evaluated using 800 chicks in a completely randomized design with four treatments, five replicates groups of 40 birds per each treatment. The treatments ...
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The effect of feeding different protein profiles on growth performance, carcass components and nitrogen content of litter in Cobb 500 broiler strain was evaluated using 800 chicks in a completely randomized design with four treatments, five replicates groups of 40 birds per each treatment. The treatments were consisted of four protein feeding profiles (based on Cobb strain nutrition guide, recommendation by NRC, 90% protein recommended by NRC and phase feeding). The effect of different treatments on body weight gain, feed intake, energy consumption, protein efficiency ratio and carcass components were not significant. The birds were fed based on Cobb strain guide had a better feed conversion ratio (P< 0.05). Energy efficiency ratio in broilers fed base on protein profile of Cobb strain guide was higher than other treatments (P< 0.05). The amount of litter nitrogen in broilers fed with base on Cobb strain guide, 90% protein recommended by NRC and phase feeding were lower than those fed base on protein profile of NRC recommendation (P< 0.05). Based on the results of this experiment, the use of protein profile base on Cobb strain is more suitable for feeding Cobb broiler chickens than other profiles.