<p>Growth performance, immune responses, antioxidant activities, biochemical and stress parameters were studied for <i>Anabas testudineus</i> fingerlings’ production in a biofloc system (BFT) for the rearing period of 70&#xa0;days at four varied stocking densities—250 (Control), 500 (T1), 750 (T2) and 1000 (T3) fry m<sup>−3</sup>. Floc development in treatment tanks was promoted by adding wheat flour (carbon supplements: C:N—15:1), along with CIBAFLOC™ (probiotic), while no carbon or probiotic source was added to the control. Fish were fed with a commercial diet (32% protein; 6% lipid). Survival remained above 85% across all treatments. However, varied densities significantly influenced the growth parameters (length, weight, weight gain, SGR % and biomass yield), with control exhibiting the highest values (<i>P</i> &lt; 0.05). Water quality parameters across all tanks were within acceptable limits for <i>Anabas</i>, while BFT treatments showed better stability of these parameters than the control. A whole-body composition analysis revealed similar crude protein and lipid levels across the densities. Digestive enzyme activities (amylase, protease and lipase) declined with increasing density, suggesting stress-induced metabolic changes. Skin mucosal immune parameters including lysozyme activity and total protein were significantly higher in T1 and T2 groups, indicating enhanced immunity. Also, superoxide dismutase (SOD), glutathione peroxidase (GPx) and all the hepatic antioxidant enzyme activities were significantly higher in T1 and T2 groups, suggesting improved resilience to oxidative stress. In contrast, fingerlings in T3 exhibited suppressed immuno- and antioxidant responses, indicating the threshold limit of this density to compromise growth and immunity. These results suggest that a moderate stocking density of up to 750 fry m<sup>−3</sup> (T2) is suggested for fingerling production of <i>A. testudineus</i> in a biofloc-based system.</p>

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Influence of different stocking densities on growth performance, water quality, immunological responses, and physiological status of Anabas testudineus fingerlings reared in a biofloc-based production system

  • Pratap Chandra Das,
  • Pushpa Choudhary,
  • Shajahan Ferosekhan,
  • Rakhi Kumari,
  • Himanshu Sekhar Swain

摘要

Growth performance, immune responses, antioxidant activities, biochemical and stress parameters were studied for Anabas testudineus fingerlings’ production in a biofloc system (BFT) for the rearing period of 70 days at four varied stocking densities—250 (Control), 500 (T1), 750 (T2) and 1000 (T3) fry m−3. Floc development in treatment tanks was promoted by adding wheat flour (carbon supplements: C:N—15:1), along with CIBAFLOC™ (probiotic), while no carbon or probiotic source was added to the control. Fish were fed with a commercial diet (32% protein; 6% lipid). Survival remained above 85% across all treatments. However, varied densities significantly influenced the growth parameters (length, weight, weight gain, SGR % and biomass yield), with control exhibiting the highest values (P < 0.05). Water quality parameters across all tanks were within acceptable limits for Anabas, while BFT treatments showed better stability of these parameters than the control. A whole-body composition analysis revealed similar crude protein and lipid levels across the densities. Digestive enzyme activities (amylase, protease and lipase) declined with increasing density, suggesting stress-induced metabolic changes. Skin mucosal immune parameters including lysozyme activity and total protein were significantly higher in T1 and T2 groups, indicating enhanced immunity. Also, superoxide dismutase (SOD), glutathione peroxidase (GPx) and all the hepatic antioxidant enzyme activities were significantly higher in T1 and T2 groups, suggesting improved resilience to oxidative stress. In contrast, fingerlings in T3 exhibited suppressed immuno- and antioxidant responses, indicating the threshold limit of this density to compromise growth and immunity. These results suggest that a moderate stocking density of up to 750 fry m−3 (T2) is suggested for fingerling production of A. testudineus in a biofloc-based system.