ارزیابی دو سیستم نیمه‌مداربسته و بیوفلاک در افزایش راندمان آب و تولید متراکم ماهی کپور معمولی (cyprinus carpio)

وقتی از 5/0 بیش‌تر باشد و یا میزان fst کم‌تر از 33/0 باشد جریان ژن را می­توان رویکرد اصلی بین جمعیت‌ها لحاظ نمود و بر عکس اگر میزان جریان ژن (nm) از 5/0 کم‌تر و میزان تفاوت ژنتیکی (fst) بیش‌تر از 33/0 باشد وجود ساختار ژنتیکی متفاوت می‌تواند مهم‌ترین عامل تفکیک جمعیت‌ها باشد.

evaluation of semi-closed and biofloc systems for enhancing water efficiency and intensive production of common carp (cyprinus carpio)

this study evaluated the effects of semi-closed and biofloc aquaculture systems on common carp (cyprinus carpio), assessing growth performance, body composition, blood biochemical parameters, and immunity. common carp with an average weight of 100.4 ± 1.08 g were selected and randomly distributed into two ponds, each containing approximately 216 m³ of water (25,000 fish per pond). the experimental treatments included a semi-closed system and a biofloc system, each with three biological replicates, arranged in a completely randomized design over a 16-week period. significant differences were observed between the two systems in terms of ammonia, nitrite, nitrate, and suspended solids (p < 0.05), while no differences were detected in temperature, dissolved oxygen, or ph (p > 0.05). growth indices did not differ significantly between the systems. regarding nutritional indices, protein efficiency was significantly higher in the biofloc system compared to the semi-closed system (p < 0.05). the biochemical composition of fish carcasses including protein, lipid, moisture, and ash showed no significant differences between the two systems (p > 0.05). urea and creatinine levels were significantly elevated in the biofloc system (p < 0.05), and lysozyme activity (an immune indicator) was also higher in this system (p < 0.05). in conclusion, the absence of significant differences in growth performance and body composition of fish fed low-protein diets in the biofloc system, compared to the semi-closed system, demonstrates the efficacy of biofloc technology as a closed-loop system for common carp aquaculture.