Iranian Scientific Fisheries Journal

fa مقاله علمی – پژوهشی:‌ اثر تعداد دفعات غذادهی بر عملکرد رشد و تغذیه‌ای فیل ماهی (Huso huso) جوان در شرایط زمستانه Effect of feeding frequency on growth and nutritional performance in juvenile Beluga sturgeon (Huso huso) under winter condition تغذيه تغذيه پژوهشي Research در این تحقیق، اثر سه وعده غذادهی 1، 2 و 3 بار تغذیه در شبانه روز روی رشد و شاخص‌های تغذیه‌ای فیل ماهی (Huso huso) جوان مورد بررسی قرارگرفت. فیل ماهیان پرورشی (4/10 ± 8/144 گرم) در سه تیمار (شامل 1، 2 و 3 بار غذادهی در روز) و هر یک با سه تکرار در مخازن بتونی گرد با حجم 800 لیتر به تعداد 20 عدد در هر مخزن توزیع شدند و در فصل زمستان (8/1±8/9 درجه سانتی‌‌گراد) به مدت 10 هفته و بر اساس اشتها مورد تغذیه قرارگرفتند. هر دو هفته یکبار، وزن و طول کل ماهیان اندازه گیری و شاخص‌های رشد و تغذیه محاسبه شدند. نتایج نشان داد، با وجود این‌که در شاخص‌های وزن نهایی، وزن کسب شده، شاخص وضعیت، افزایش وزن بدن، نرخ رشد ویژه، ضریب تبدیل غذایی و شاخص تغذیه اختیاری اختلافی بین تیمارها وجود نداشت (05/0p>)، اما در اکثر شاخص‌ها، ماهیان تغذیه شده در تیمار با 3 وعده غذادهی به لحاظ عددی، وضعیت بهتری نشان دادند. همچنین ضریب تغییرات وزن در بین گروه‌ها، اختلافی را آشکار نساخت (05/0p>)، ضمن این‌که در طول دوره نیز تلفاتی مشاهده نشد. نتایج این تحقیق نشان داد، به رغم پایین بودن دمای آب، فیل ماهیان نیاز به تغذیه دارند و 3 بار غذادهی روزانه می‌تواند رشد مطلوب‌‌تری ایجاد نماید، اما با در نظر گرفتن عدم اختلاف معنی‌‌دار در شاخص‌های رشد و تغذیه و کاهش هزینه‌های تولید، یک‌بار غذادهی در روز می‌تواند در محدوده وزنی مورد آزمایش و در شرایط زمستانه نیز مورد استفاده پرورش‌دهندگان قرار گیرد. Introduction The growth of aquatic animals in cultured systems depends on various factors such as food consumed, feeding frequencies, diet quality, the amount of consumed feed, and the ability of fish to digest and absorb nutrients (Falahatkar et al., 2014). Meeting nutritional requirements and proper nutrition management are crucial for increasing production efficiency in farmed fish. In aquaculture conditions, cost reduction is essential, with nutrition accounting for approximately half of the current costs on a farm. The quantity and quality of diets, along with feeding management practices such as feeding frequencies, feeding methods, feeding amounts, and timing, can impact final product costs. Appropriate feeding frequencies not only improve feed conversion efficiency and reduce pollution from overfeeding but also enhance growth and reduce size disparities in fish stocks. Nutritional management is a critical aspect to consider in sturgeon aquaculture, emphasizing proper nutrition and feeding frequency at different temperatures (Hung, 2017). Given the high growth rate of Beluga sturgeon (Huso huso) in culture systems and the interest of fish farmers in cultivating this species (Falahatkar et al., 2009), especially in natural waters subject to seasonal fluctuations, this study aimed to investigate the effect of different feeding frequencies on the growth and nutritional indices of juvenile Beluga sturgeon in winter conditions. Methodology This study evaluated the effect of three feeding frequencies (1, 2, and 3 times per day) on the growth and nutritional indices of juvenile Beluga sturgeon. Farmed Beluga sturgeon (144.8±10.4 g) were distributed into three treatments, each with three replicates in circular concrete tanks (800 L volume) with 20 fish per tank. The feeding trial took place during the winter period (8.9±1.8°C) from January to March over a 10-week period. Fish were fed approximately 0.1-0.3% of their body weight per feeding at 9 AM, 12 PM, and 3 PM, based on appetite and water temperature. Fish weight and total length were measured individually every 2-week interval, and growth and feeding indices were calculated (Falahatkar, 2014). Statistical analysis was performed using One-way ANOVA and Tukey as a post-hoc test at the level of p<0.05. Results Over the 10-week rearing period, there were no significant differences in fish weight and length among the different feeding frequency treatments (p>0.05). While there was no statistical difference in final weight, weight gain, condition factor, body weight increase, specific growth rate, feed conversion ratio, and voluntary feeding intake among the treatments (p>0.05), fish fed three times a day generally exhibited better condition. The coefficient of variation in weight was lower in fish fed three times daily, although differences were not significant (p>0.05). No mortality was observed during the 10-week period, with 100% survival in all treatments. Discussion and conclusion This study examined the effects of different feeding frequencies on the growth and nutritional indices of juvenile Beluga sturgeon under winter conditions. After 10 weeks, no significant differences were observed in any of the measured indices across the 1, 2, or 3 feeding frequency treatments. All fish remained healthy with no mortality recorded. Previous studies have shown that limited feeding frequency leads to the adaptation of fish to consume larger amounts of food at feeding time, which in the long term can lead to increased digestive tract volume and increased appetite (Jobling, 1982; Rouhonen and Grove, 1996). Moreover, optimal feeding frequency can enhance feed conversion efficiency, reduce pollution, promote growth, and minimize size variations in fish stocks (Ahmed, 2007; Hu et al., 2020). However, previous studies suggested different feeding rates for maximum growth or weight maintenance in winter conditions (Fang et al., 2010; Falahatkar et al., 2013). The present study showed a feeding rate of 0.8% of body weight yielded satisfactory growth. Although growth and nutritional indices did not differ significantly, further stocking management may be necessary to address size variations. In conclusion, feeding once daily, as opposed to three times, can reduce labor and production costs, provided that fish receive adequate food based on their requirements. Conflict of interest The authors declare no conflicts of interest for this study. Acknowledgements The authors acknowledge the Dr. Yousefpour Marine Fishes Restocking and Genetic Conservation Center (Siahkal, Guilan, Iran) and the Vice Chancellor for Research at the University of Guilan for their support in conducting this research. ماهی خاویاری, دمای پایین, برنامه غذادهی, رشد, اختلاف اندازه Sturgeon, Low temperature, Feeding schedule, Growth, Size variation 51 62 http://isfj.ir/browse.php?a_code=A-10-86-21&slc_lang=fa&sid=1 Bahram Falahatkar بهرام فلاحتکار falahatkar@guilan.ac.ir 100319475328460041899 100319475328460041899 Yes Fisheries Department, Faculty of Natural Resources, University of Guilan, Someh Sara, Iran گروه شیلات، دانشکده منابع طبیعی، دانشگاه گیلان، صومعه‌سرا، گیلان، ایران Bahman Meknatkhah بهمن مکنت‌خواه bahmanmeknatkhah@yahoo.com 100319475328460041900 100319475328460041900 No Fisheries Department, Faculty of Natural Resources, University of Guilan, Someh Sara, Iran گروه شیلات، دانشکده منابع طبیعی، دانشگاه گیلان، صومعه‌سرا، گیلان، ایران Iraj Efatpanah ایرج عفت پناه iefatpanah@yahoo.com 100319475328460041901 100319475328460041901 No Fisheries Department, Faculty of Natural Resources, University of Guilan, Someh Sara, Iran گروه شیلات، دانشکده منابع طبیعی، دانشگاه گیلان، صومعه‌سرا، گیلان، ایران Samaneh Poursaeid سمانه پورسعید s.poursaeid@yaho.com 100319475328460041902 100319475328460041902 No Department of Cell Biology, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT 06030-4035, USA گروه بیولوژی سلولی، مرکز بهداشت دانشگاه کنتیکت، فارمینگتون، کنتیکت، آمریکا