تاثير سطوح مختلف انرژي قابل متابوليسم و پروتئين خام جيره بر عملكرد رشد، خصوصيات لاشه و راندمان انرژي و پروتئين دوره آغازين بلدرچين هاي ژاپني

Effect of different levels of dietary metabolizable energy and protein on growth performance, carcass traits and energy and protein efficiency of Japanese quails in the starter period

زمينه مطالعاتي: سطح مطلوب انرژي و پروتئين مورد نياز بلدرچين ژاپني در دوره هاي مختلف پرورش (آغازين، رشد و پاياني) باعث بهبود رشد و عملكرد پرنده مي شود. هدف: بررسي تاثير سطوح مختلف انرژي قابل متابوليسم و پروتئين جيره بر راندمان انرژي و پروتئين، خصوصيات لاشه و عملكرد بلدرچين هاي ژاپني در دوره آغازين. روش كار: آزمايشي با استفاده از 450 قطعه جوجه يك روزه بلدرچين ژاپني در قالب طرح كاملاً تصادفي به روش آزمون فاكتوريل 3×3 با 5 تكرار و 10 قطعه جوجه در هر تكرار براي مدت 10 روز بر روي بستر انجام شد. جيره هاي آزمايشي شامل 3 سطح انرژي قابل متابوليسم (2700، 2800 و 2900 كيلوكالري در هر كيلوگرم جيره غذايي) و 3 سطح پروتئين خام (24، 25 و 26 درصد) بودند. در پايان دوره آزمايشي يك قطعه پرنده از هر تكرار به صورت تصادفي انتخاب و جهت بررسي خصوصيات لاشه كشتار گرديد. نتايج: پرندگان تغذيه شده با جيره حاوي انرژي 2800 كيلوكالري در كيلوگرم و 24 درصد پروتئين خام، بازدهي لاشه، وزن ران و افزايش وزن كمتر و ضريب تبديل خوراك بيشتري در مقايسه با پرندگان ساير تيمارها داشتند (0/05>P). افزايش سطح پروتئين جيره تاثيري بر افزايش وزن و ضريب تبديل خوراك نداشت (0/05P). همچنين مشخص گرديد كه سطح انرژي قابل متابوليسم جيره بر راندمان پروتئين، تاثير معني داري داشت (0/05>P)، به نحوي كه پرندگان تغذيه شده با سطح انرژي 2900 كيلوكالري در كيلوگرم، راندمان پروتئين بهتري را نشان دادند. با افزايش انرژي جيره، پروتئين مصرفي به لحاظ عددي كاهش يافت (0/095=P). علاوه براين سطح پروتئين جيره بر مقدار پروتئين مصرفي تاثير معني دار داشت، به طوري كه با افزايش سطح پروتئين جيره از 24 به 26 درصد، پروتئين مصرفي توسط پرندگان نيز افزايش پيدا كرد (0/05>P). پرندگان تغذيه شده با سطوح انرژي 2700 و 2900 كيلوكالري در كيلوگرم به ترتيب بيشترين و كمترين درصد پروتئين لاشه را داشتند (0/05>P) و پرندگان تغذيه شده با 25 و 26 درصد پروتئين خام بيشترين و پرندگان تغذيه شده با 24 درصد پروتئين خام كمترين درصد رطوبت لاشه را نشان دادند (0/05>P). نتيجه گيري نهايي: نتايج حاصل از اين مطالعه پيشنهاد مي كند كه استفاده از سطح انرژي 2700 كيلوكالري در كيلوگرم و سطح پروتئين خام 24 درصد در جيره آغازين، موجب بهبود عملكرد توليدي بلدرچين هاي ژاپني مي شود.

Introduction: Determination of optimum level of energy and protein requirements for Japanese quail in different periods (starter, grower and finisher) improves the growth performance and economic efficiency. This study was conducted to investigate the effect of different levels of dietary energy and protein on energy and protein efficiency, carcass characteristics and performance of Japanese quail during starter period. Materials and method: Experiment was performed by 450 one-day-old quail chicks based on a completely randomized design in a 3 × 3 factorial arrangement with 5 replicates and 10 chicks per replicate. Experimental diets containing 3 levels of energy (2700, 2800 and 2900 kcal/kg) and 3 levels of protein (24, 25 and 26 %). Before the formulation of diets, the chemical composition of feed ingredients were determined by Near Infrared Spectroscopy (NIR). Experimental diets were formulate based on corn-soybean meal using the WUFFDA software for the starter period (1 to 10 days). At the end of experiment (10 d), a bird was randomly selected and slaughtered to evaluate carcass characteristics. Results and discussion: Feed intake was not affected by dietary energy or protein levels (P>0.05), although energy levels of 2800 and 2900 kcal/kg reduced the feed intake numerically (P = 0.098). In addition, there was no interaction between dietary energy and protein levels for feed intake (P>0.05). Increasing the dietary protein level had no effect on weight gain and feed conversion ratio (P>0.05), but the dietary energy level affected the both weight gain and feed conversion ratio (P<0.05). The highest energy level (2900 kcal/kg) caused the decreased feed conversion ratio while having no effect on weight gain compared to the lowest energy level (2700 kcal/kg), whereas consumption of 2800 kcal/kg decreased the weight gain as compared to the lowest and highest energy levels (P<0.05). Moreover, there was a significant interaction between the energy and protein for the weight gain and feed conversion ratio (P<0.05). At lowest and highest energy levels, the increase in protein level did not affect the body weight gain, but in the medium energy level, a decrease in protein level to 24% led to body weight reduction. Furthermore, the increase of protein level at lowest and medium energy levels did not effect the feed conversion ratio, but at highest energy level, increasing protein to 25% decreased the feed conversion ratio (P<0.05). The different levels of dietary protein (24 to 26%) had not significant effect on the performance traits (feed intake, weight gain and feed conversion ratio) (P>0.05). The energy level had a significant effect on weight gain and feed conversion ratio (P<0.05), so that chicks fed with 2700 and 2900 kcal/kg energy had higher weight gain and lower feed conversion ratio. None of the carcass parameters and organ weights were affected by the dietary energy level (P>0.05), although the energy level of 2700 kcal/kg increased the breast weight (P= 0.056). The dietary protein level had a significant effect on carcass and thigh weights (P<0.05). The medium (25%) and lowest (24%) protein levels increased and decreased the carcass and thigh relative weights respectively (P<0.05), while the highest protein level (26%) did not change the carcass and thigh weights as compared to the lower protein levels. Moreover, there was a significant interaction between the energy and protein for both the carcass and thigh relative weights (P<0.05). At the medium and highest protein levels, the increase in energy levels did not affect the carcass and thigh weights, but at lowest protein level (24%), an increase in energy level to 2800 kcal/kg resulted in lower carcass and thigh weights (P<0.05). The effects of different dietary protein levels was not significant for breast and liver weight (P>0.05), but the energy level of 2700 kcal/kg and protein level of 24% increased the breast weight numerically (P=0.056). The dietary protein level had a significant effect on protein consumption (P<0.05), the protein levels of 26% and 24% showed the highest and lowest protein consumption respectively. The interaction between energy and protein on the energy efficiency ratio and protein efficiency ratio was not significant (P>0.05), but at the lowest energy level (2700 kcal/kg), reduction of protein level to 24% resulted in an increase of energy efficiency ratio numerically (P=0.0680). Moreover, at the highest energy level (2900 kcal/kg) reduction of protein level to 24% resulted in an increase of protein efficiency ratio numerically (P=0.073). The carcass fat content was not affected by dietary energy or protein level (P>0.05). The dietary energy level had a significant effect on carcass protein content (P<0.05), the energy levels of 2700 and 2900 kcal/kg showed the highest and lowest carcass protein contents respectively. Also, dietary protein level had a significant effect on carcass moisture (P<0.05), the protein levels of 25% and 26% had the highest and protein level of 24% had the lowest carcass moisture contents. The interaction between the energy and protein was not significant for none of the carcass meat nutrients (P>0.05). Conclusion: The results of current study showed that the energy level of 2700 kcal/kg along with 24% crude protein in starter diets, can improve the growth performance of Japanese quail.