نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه فردوسی مشهد

2 استاد تغذیه طیور، گروه علوم دامی، دانشگاه فردوسی مشهد، مشهد

چکیده

این آزمایش به‌منظور بررسی اثر سطح پروتئین قابل‌هضم و توازن ‌الکترولیتی جیره پایانی بر عملکرد، فراسنجه‌های خون و بافت‌شناسی روده با استفاده از تعداد 500 قطعه جوجه گوشتی مخلوط دو جنس سویه راس‌308 در قالب طرح کاملاً تصادفی و به‌صورت فاکتوریل 5×2 با دو سطح پروتئین ‌قابل ‌هضم (5/16 و 19درصد) و پنج سطح توازن ‌الکترولیتی (150، 200، 250، 300 و 350 میلی‌اکی‌والان در کیلوگرم‌جیره) در دوره پایانی (25 تا 42 روزگی) با پنج تکرار 10 قطعه­ای انجام شد. جوجه­­ها از 42-28 روزگی به مدت هشت ساعت روزانه تحت تنش گرمایی 2±32 درجه ‌ سانتی­گراد قرار گرفتند. افزایش سطح پروتئین اثری بر افزایش وزن دوره پایانی جوجه­های گوشتی تحت تنش گرمایی نداشت. مصرف خوراک و ضریب تبدیل جوجه­های ‌گوشتی تغذیه شده با جیره 5/16درصد، بیشتر از 19درصد پروتئین بود (05/0­<­P). بیشترین افزایش وزن و کمترین ضریب تبدیل در توازن 200 میلی‌اکی‌والان مشاهده شد که تفاوت آنها به ترتیب تنها با تیمارهای 300 و 150 میلی‌اکی‌والان معنی‌دار نبود. بیشترین افزایش وزن در جوجه­های گوشتی تغذیه شده با جیره حاوی 5/16درصد پروتئین و 200 میلی‌اکی‌والان توازن ‌الکترولیت مشاهده شد(05/0­<­P). سرم جوجه­های تغذیه شده با جیره حاوی 19درصد در مقایسه با 5/16درصدپروتئین ‌قابل ‌هضم، دارای تری‌گلیسیرید کمتر اما پروتئین کل، کراتینین و اسید اوریک بالا­تری بودند (05/0­<­P). افزایش پروتئین جیره از 5/16درصد به 19درصد، تأثیری بر ویژگی‌های بافت‌شناسی روده نداشت. تغذیه جوجه­های گوشتی تحت تنش گرمایی با تعادل الکترولیتی 250 میلی‌اکی‌والان، مساحت سطح پرز را افزایش داد (05/0­<­P). بر اساس نتایج حاصل، در دوره پایانی پرورش جوجه­های گوشتی در شرایط تنش گرمایی، جیره حاوی 5/16درصد پروتئین قابل هضم و توازن الکترولیتی 200 میلی‌اکی‌والان توصیه می‌شود.

کلیدواژه‌ها

عنوان مقاله [English]

Effects of digestible protein and electrolyte balance level in finisher diet on performance, intestine morphology and blood parameters of broiler chickens under heat stress

نویسندگان [English]

  • Bashir Ghasempour 1
  • Abolghasem Golian 2
  • Ahmad hassanabadi 2

2 Department of Animal Science, Ferdowsi University of Mashhad, Mashhad, Iran

چکیده [English]

This experiment was conducted to evaluate the effect of varying levels of digestible protein (DP) and dietary electrolyte balances (DEB) during the finisher period on performance, blood parameters and small intestine histology of broiler chickens exposed to heat stress. A total of 500 mixed sex chickens (Ross 308) were used in a completely randomized design as a 2×5 factorial arrangement with two levels of DP (%16.5 and %19) and five levels of DEB (150, 200, 250, 300 and 350 meq/kg of diet)with five replicates of 10 birds each during the finisher period. The chicks were exposed to heat stress of 32±2 °C for eight hours/day during 28-42 days of age. Increasing DP levels did not have a significant effect on weight gain under heat stress during the finisher period. Feed intake and feed conversion ratio (FCR) of chickens fed 16.5% DP diet was significantly more than 19% DP fed birds (P<0.05). The highest weight gain and lowest FCR were observed in chickens fed 200 mEq/kg of diet EBD which were significantly different only with 300 and 150 mEq/kg EBD treatments. The highest weight gain was observed in broilers fed diet containing 16.5% DP and 200 mEq EBD. Broilers fed diet containing 19% DP in compare to those fed 16.5% DP had lower plasma triglycerides and higher total protein, creatinine, and uric acid contents. Increasing digestible protein from 16.5% to 19% had no significant effect (P>0.05) on small intestine morphology. Diet containing 250 mEq/kg of diet EBD significantly (P<0.05) increased villi surface of small intestine in chickens suffering heat stress. It is concluded that, feeding of broiler chickens exposed to heat stress during the finishing period with diet containing 16.5% digestible protein and 200 mEq/kg dietary electrolyte balances is recommendable.

کلیدواژه‌ها [English]

  • Broiler Chickens
  • dietary electrolyte balance
  • digestible protein
  • heat stress
  • Performance

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