تاثیر مخلوطی از پروتئین‌های گیاهی و جانوری بر پایه گلوتن ذرت بر شاخص‌های رشد و بافت‌‌ دستگاه گوارش فیل‌ماهی (huso huso)

به ‌منظور کاهش سهم آرد ماهی در جیره غذایی فیل‌ماهی جیره پایه‌ای مبتنی بر 54 درصد آرد ماهی ساخته شد. مخلوطی از پروتئین‌های جانوری و گیاهی (گلوتن ذرت: 35 درصد، گلوتن گندم: 19.34 درصد، آرد سویای فرآوری شده: 3 درصد، پودر ضایعات مرغ: 20 درصد، پودر گوشت و استخوان: 8 درصد، پودر خون: 4.3 درصد)، در سطوح 20، 40، 60 و 80 درصد جایگزین آرد ماهی (fm) شد (به‌ترتیب cgm20،cgm40، cgm60 و cgm80) و در نهایت 5 جیره با سطوح یکسان نیتروژن (44 درصد پروتئین خام) و انرژی (18 مگاژول/کیلوگرم) تولید گردید. فیل‌ماهیان با میانگین وزن 6.5 ±167 گرم تا حد سیری بر اساس تجربیات کارگاهی به مدت 12 هفته تغذیه شدند. در پایان دوره تغذیه جهت مطالعات بافت‌‌شناسی،30 درصد جمعیت ماهیان از هر مخزن برداشت گردید. سه قسمت از روده (بافت‌‌های قدامی، میانی و خلفی) برداشت شد. تثبیت و رنگ‌آمیزی شد. با استفاده از میکروسکوپ نوری مجهز به مانیتور، مطالعات بافت‌شناسی انجام شد. بافت روده ماهیان تغذیه‌شده با جیره cgm80 دچار نکروز و رکود صفراوی بود. اما مطالعات بافت‌شناسی در ماهیان تغذیه‌شده با جیره‌های fm، cgm20،cgm40  و  cgm60نشان داد که فضای لامینا پروپریا در حد مناسب، نکروزه شدن انتروسیت‌ها در حد ناچیز و تعداد سلول‌های جامی روده قدامی، میانی و انتهایی در حد متعادلی قرار دارد. نتایج نهایی بر این نکته اذعان داشت که جیره cgm80 تاثیر منفی بر رشد ماهیان ندارد، ولی موجب آسیب به دستگاه گوارش گردید. بنابراین، پیشنهاد می‌شود که در جیره غذایی فیل‌ماهی در مرحله پرواربندی مخلوطی از پروتئین‌های جانوری و گیاهی در سطوح 20 و 40 درصد جایگزین آرد ماهی در نظر گرفته شود.

effect mixture of vegetable and animal proteins based on corn gluten on growth rate and digestive tract tissue of beluga (huso huso)

introduction fishmeal price were increasing every year and predicted that fish diet will have a wider range of ingredients replaced by fishmeal, such as vegetable sources, microbial protein sources, waste from fishing and animal protein waste (glencross et al., 2007). vegetable proteins can replace fish meal to some extent and have a negative effect on the growth of aquatic animals at high levels. but many studies have shown that a mixture of vegetable proteins can improve the amino acid profile compared to single protein source replaced by fish meal (amaya et al., 2007).  by this method, high replacement with a blend of protein vegetables have been reported in aquatic animal (hansen et al., 2007), but increasing fiber, increasing carbohydrates and inappropriate amino acids in diets based on animal and vegetable proteins can led to a negative effect on fish digestive system that showed by growth reduction, immune system depress , low quality meat and even fish fatality in a long-term feeding period (raskovic et al., 2011). therefore, in this experiment, the effect of a mixture of animal and vegetable proteins replaced by fish meal (levels of 20, 40, 60 and 80%) on the growth indices and digestive system tissue huso huso were studied. methodology in order to reduce the share of fishmeal in the diet of beluga, a basal diet based on 54% of fishmeal was made. a mixture of animal and vegetable proteins (corn gluten: 35%, wheat gluten: 19.34%, processed soybean flour: 3%, chicken by-products: 20%, meat and bone meal: 8%, blood meal: 3.4%) at 20, 40, 60 and 80% levels replaced with fishmeal (fm) (cgm20, cgm40, cgm60, and cgm80, respectively) and finally 5 isonitrogenous (44% crude protein) and isoenergetic (18 mj/kg) diets were produced. the fish (average weight: 167±6.5 gr) were fed to saturation for 12 weeks.  biometry were carried out on month interval and by carrying out information obtained from fish length, weight and food consumption, growth indices and feed efficiency ratio were calculated. at the end of the feeding period, 30% of the fish population was collected from each tank for histological studies. three parts of the intestine (hindgut, midgut, and foregut) were removed. it was fixed and stained. histological studies were carried out by an optical microscope equipped with a monitor. results there was no significant difference in the final weight and length of fish of different treatments (p>0.05). condition factor and percentage of weight gain of fish fed with fm, cgm20, cgm40, cgm60 and cgm80 had no no significant difference and percentage of weight gain was close to each other (243 to 298%) (p>0.05). no significant difference was observed in specific growth rate and daily growth rate and food conversion ratio in fish fed with all diets (p>0.05). fish fed fm had the highest protein efficiency ratio (1.75±0.23), but protein efficiency ratio in fish fed with cgm20, cgm40, cgm60 and cgm80 was in the range of 1.53 to 1.73%. but no significant difference was observed (p>0.05). histological studies were carried out by an optical microscope equipped with a monitor. the intestinal tissue of fish fed with cgm80 diet had necrosis and biliary stagnation. however, histological studies in fish fed with fm, cgm20, cgm40, and cgm60 diets showed that the lamina propria space is adequate, the necrosis of enterocytes is negligible, and the number of goblet cells in the anterior, middle, and distal intestine is balanced.