ارزيابي عملكرد، سيستم ايمني و خصوصيات آنتي‌اكسيداني سرم در جوجه‌هاي گوشتي تغذيه شده با جيره‌هاي بر پايه گندم حاوي سطوح مختلف نانو ‌اكسيد ‌روي از 1 تا 21 روزگي

Effects of zinc oxide nanoparticles on immune system function, antioxidant status, and performance of broiler chickens fed wheat-based diets

زمينه مطالعاتي: روي يك عنصر حياتي براي رشد و فرآيند‌هاي فيزيولوژيك مختلف در حيوانات است. هدف: اين آزمايش به منظور بررسي تأثير سطوح مختلف نانو اكسيد روي (ZONPs) در جيره‌هاي بر پايه گندم بر عملكرد و سيستم ايمني جوجه‌هاي گوشتي انجام شد. روش كار: تعداد 240 قطعه جوجه خروس گوشتي يك‌روزه سويه راس 308، در قالب يك طرح كاملا تصادفي با 6 تيمار و 4 تكرار استفاده شد. تيمار‌هاي آزمايشي شامل يك جيره‌ بر پايه گندم (شاهد، فاقد روي در مكمل معدني مورد استفاده) و جيره‌هاي مكمل شده با 20، 40، 60، 80 و 100 ميلي‌گرم در كيلوگرم روي از منبع ZONPs بود. به منظور بررسي عملكرد جوجه‌ها، خوراك مصرفي و افزايش وزن جوجه‌ها بطور هفتگي اندازه‌گيري و ضريب تبديل محاسبه شد. جهت بررسي پاسخ ايمني همورال، تزريق گلبول‌هاي قرمز خون گوسفند (SRBC) در سن 7 روزگي صورت گرفت. هفت و 14 روز پس از تزريق، خونگيري انجام شد و ميزان تيتر آنتي‌بادي عليه SRBC تعيين گرديد. جهت بررسي پاسخ ازدياد حساسيت بازوفيلي پوستي (CBH)، در روز 20 آزمايش تزريق فيتوهماگلوتينين (PHA-P) به مقدار ۰/۱ميلي‌ليتر بين پوست انگشتان پا صورت گرفت و تغيير ايجاد شده در ضخامت پوست اندازه‌گيري شد. جهت بررسي وضعيت آنتي‌اكسيداني سرم خون، غلظت مالون‌دي‌آلدهيد (MDA) در نمونه‌هاي گرفته شده در سن 21 روزگي (2 پرنده از هر تكرار) اندازه‌گيري شد. جهت اندازه‌گيري ويسكوزيته شيرابه هضمي، در روز 21 از هر تكرار دو پرنده كشته شده و محتويات ژژنوم و ايلئوم نمونه‌گيري شد. نتايج: افزودن 80 ميلي‌گرم روي در هر كيلوگرم جيره سبب افزايش مصرف خوراك در دوره‌هاي 1 تا 7 و 1 تا 14 روزگي، در مقايسه با تيمار شاهد شد (۰/۰۵>P). همچنين، افزودن 80 ميلي‌گرم روي در هر كيلوگرم جيره سبب كاهش ويسكوزيته محتويات ژژنوم و ايلئوم، افزايش تيتر آنتي‌بادي عليه SRBC در 14 روز پس از تزريق، و كاهش غلظت سرمي مالون‌دي‌آلدهيد در مقايسه با تيمار شاهد شد (05/0>P). از سوي ديگر، افزودن 60 ميلي‌گرم روي در هر كيلوگرم جيره سبب افزايش پاسخ CBH در مقايسه با تيمار شاهد، در 12 ساعت بعد از تزريق شد (۰/۰۵>P). نتيجه‌گيري نهايي: با توجه به نتايج اين تحقيق به نظر مي‌رسد كه افزودن روي از منبع ZONPs در مقادير 60 تا 80 ميلي‌گرم در هر كيلوگرم جيره، مي‌تواند در تقويت سيستم ايمني و افزايش مقاومت آنتي‌اكسيداني سرم خون جوجه‌هاي گوشتي موثر باشد.

Introduction: Using supplements and additives for growth enhancement and improved production is currently a routine method in animal production. Recently, several mineral supplements using nanotechnology has been developed for use in animal production systems such as Nano - silver, Nano - selenium, and Nano - zinc oxide. Zinc is an essential nutrient for growth and different physio logical functions in animals. Since, a considerable part of zinc in poultry feeds is as the form of compounded with phytic acid which is not easily available in gastrointestinal tract, maintaining a good balance of this element in poultry diets is essentia l. In most of the diets formulated for poultry, zinc is supplemented in order to meet the requirements. Zinc requirements for poultry has been reported from 10 mg/kg to 100 mg/kg of the diet for different purposes in different literatures. Zinc is essentia l for the optimum activity of about 300 enzymes and is incorporated in many different metabolic pathways in the body. Using high NSP rations in poultry nutrition such as wheat based diets, causes considerable injury to intestinal epithelium which is relate d to a reduction in nutrients absorption. Zinc as an essential nutrient is effective in maintaining intestinal wall health and integrity. This experiment was conducted to evaluate the effect s of a wheat - based diet (WBD) supplemented whit different levels o f zinc (Zn) in the form of zinc oxide nanoparticles (ZONPs) on performance and immune system of broiler chickens. Material and m ethod s : A total of 240 day - old Ross 308 male broiler chicks in a completely randomized design with 4 replicates of 10 chicks p er each were used. Six dietary treatments were prepared as follow: a WBD without Zn supplement in mineral premix as control, and 5 WBD supplemented with 20, 40, 60, 80, and 100 mg/kg Zn from the source of ZONPs , respectively . The basal diet was formulated to meet minimum requirements as described by NRC (1994). The used lighting program was as 23 h light/1 h darkness in each 24 h period. Feed and water were freely available during the entire period of the experiment. Feed intake (FI), body weight gains (BWG ), and feed conversion ratio (FCR) were recorded weekly. Sheep red blood cells (SRBC) (2% V/V) as an antigen was injected to thigh muscle on 7 days of age. Seven and 14 days after injection, blood samples were collected via brachial vein and antibody titer s against SRBC were measured in obtained serum . For this, log 2 of the reciprocal of the dilution factor corresponding to the last well in which hemagglutination inhibition was visible , were recorded as antibody titer. In order to evaluate cutaneous basophi l hypersensitivity ( CBH ) response, on day 20 , 8 chicks per treatment were randomly selected and 0.1 ml phytohemagglutinin - p (PHA - P ) dissolved in phosphate buffered saline (PBS, 1 μ g in 1 μ l) were injected subcutaneously between toe web of left leg. Simulta neously, PBS (0.1 ml) alone was injected to toe web of the right leg. Twelve and 24 hours after injection, the thickness of the toe web s were measured and recorded . The response to CBH was calculated by subtracting the thickness of the web in the right leg from the thickness of the web in the left leg. On day 21, serum samples of 2 chicks from each replicate were collected for malondialdehyde (MDA) measurement. Two chicks from each replicate were randomly selected on day 21, euthanized and jejunal and ileal digesta were sampled for viscosity measurement. R esults and d iscussion : Supplementation of the WBD with 80 mg Zn/kg in the form of ZONPs, caused a significant increase in FI for periods of 1 to 7 and 1 to 14 days of age compared to control group (p<0.05) . Also, s upplementation of the WBD with 80 mg Zn/kg in the form of ZONPs, caused a significant increase in anti - SRBC titer on 14 days post injection, and decreased serum MDA concentration and jejunal and ileal digesta viscosity, compared to control group ( p<0.05). Furthermore, s upplementation of the WBD with 60 mg Zn/kg in the form of ZONPs, significantly increased CBH response compared to control group (p<0.05). Conclusion : Overall, it can be concluded that supplementation of the WBD with 60 to 80 mg Zn/kg from the source of ZONPs, would improve immune system and serum antioxidant properties of broiler chickens.