کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2446853 1553940 2016 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
How heat stress (continuous or cyclical) interferes with nutrient digestibility, energy and nitrogen balances and performance in broilers
ترجمه فارسی عنوان
چگونه استرس گرمایی (مداوم یا دوره ای) باعث اختلال در هضم مواد مغذی، تعادل انرژی و نیتروژن و عملکرد جوجه های گوشتی می شود
کلمات کلیدی
استرس گرمایی ادواری؛ استرس گرم مداوم؛ قابلیت هضم مواد غذایی؛ تولید گرما؛ بازده نیتروژن؛ تغذیه زوج
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم دامی و جانورشناسی
چکیده انگلیسی


• Both cyclical and continuous heat stress affects negatively broilers’ feed intake.
• Only the continuous heat stress decreased dry matter and protein digestibility.
• Energy and nitrogen efficiencies were reduced by the continuous but not by the cyclical heat stress.

The effect of continuous and cyclical heat stress on broiler growth performance, nutrient digestibility, energy and nitrogen balances was investigated. Four hundred and fifty, 21-day-old, Cobb male broilers were raised in battery cages in five treatments: 22C/AL (continuous 22 °C, ad libitum feed consumption); 32C/AL (continuous 32 °C, ad libitum feed consumption); 22C/PF32C (continuous 22 °C, pair-fed on the daily feed intake of 32C/AL); CY/AL (cyclical – 32 °C for 8 h and 25 °C for 12 h, ad libitum feed consumption); 22C/PFCY (continuous 22 °C, pair-fed on the daily feed intake of CY/AL). Between 39 and 42 days of age, dry matter, crude protein, crude fat and AMEn were analyzed in the diets and excreta to determine nutrient digestibility. Energy and nitrogen balances were evaluated through comparative slaughter (21 and 42 days of age). Growth performance was significantly lower in broilers exposed to either continuous or cyclical heat stress. However, the cyclical heat stress had a lower effect on feed intake and weight gain and no effect on the feed conversion rate. Nutrient digestibility was only influenced by continuous heat exposure, decreasing dry matter (3.9%) and protein digestibility (9.7%) in comparison to control birds. Broilers exposed to continuous heat stress increased metabolizable energy intake (20.3%) and heat production (35.5%), and decreased energy retention (20.9%) and energy efficiency (32.4%) in relation to control ones. Nitrogen intake and nitrogen retention were reduced by both forms of heat exposure, in comparison to control, but more strongly under continuous heat. Nitrogen retention was reduced by 50.4% and 20.4%, for continuous or cyclical heat stress, respectively. Nitrogen efficiency was reduced only by the continuous heat exposure (33.1%). These results revealed important differences between the effects of a continuous or a cyclical heat exposure in broiler chickens for digestibility, performance and energy and nitrogen balances.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Livestock Science - Volume 192, October 2016, Pages 39–43
نویسندگان
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