Central Institute of Fisheries Education

Biomimicry systems represent an innovative aquaculture strategy that restores the natural ecological balance by stimulating beneficial microbial communities and enhancing nutrient recycling. Therefore, to identify a sustainable rearing system, a 75-day study was conducted to assess the effects of stocking density on the growth performance and gene expression of red tilapia (Oreochromis sp.) reared in conventional and biomimicry systems. For this, a 2 x 3 factorial design was designed, with two rearing systems: conventional (T1) and biomimicry culture system (T2), using fermented de-oiled palm kernel meal (DPKM) to enhance microbial and plankton productivity. Each system had three stocking densities-L-low (2 fish/m2), M-medium (3.5 fish/m2), and H-high (5 fish/m2)-resulting in six treatments: T1L, T1M, T1H, T2L, T2M, and T2H. Red tilapia fingerlings of uniform size (9.00 f 0.02 g) were stocked at the respective stocking densities. The biomimicry system significantly improved growth, with T2L achieving the highest final weight (110.60 f 1.77 g), followed by T2M, T1L, T2H, T1M and T1H. The feed conversion ratios were lower in the T2 group, indicating better feed efficiency. Survival was highest in T2L (98.75 f 1.25 %) and lowest in T1H (81.50 f 2.50 %) treatments. Enzyme analysis showed reduced antioxidant (SOD and catalase) and metabolic enzyme (LDH and MDH) activities in the T2 group, suggesting lower stress levels. Gene expression analysis showed upregulation of growth-related (GH, IGF-1) and immune-related (IgM) genes and downregulation of stress-related (HSP-70) gene in the T2 biomimicry system. Overall, T2M treatment provided optimal growth, feed efficiency, survival, and stress tolerance, with a better cost-benefit ratio than T1M, demonstrating the potential of the biomimicry system as a sustainable farming practice in red tilapia aquaculture.

Fungal enzootics and epizootics cause significant biological loss in fisheries and aquaculture necessitating and sometimes forcing non-legal use of veterinary medicinal products sans essential scientific data on drug efficacy, kinetics, residue levels, etc. The present study determines the pharmacokinetics, bioavailability and tissue depletion of clotrimazole (CTZ), one of the oldest and most effective azoles against a major fungal pathogen Saprolegnia parasitica, following enteral and parenteral administrations in widely consumed catfish Pangasianodon hypophthalmus. The drug residues in fish tissues at different time points were quantified by LC-MS/MS. The results showed very slow kinetics including absorption/distribution, and elimination of CTZ, especially after parenteral administration. Following bolus oral administration, the drug underwent first pass with negligible clearance from liver, and very high residence time in all the tissues. However, high AUC/MIC ratio, Cmax> MIC and prolong

The present study evaluated the impact of different stocking densities (SD 10, SD 20, and SD 30 fish m−3) on the growth, survival, physiological responses, and economic returns in Amur carp (Cyprinus carpio haematopterus) reared in cages for 180 days. The juveniles of Amur carp (12.27 ± 0.31 cm; 35.6 ± 3.16 g) were stocked in galvanised iron cages in triplicate and fed with a floating pellet diet (28% CP, 4% CF) at a gradually reduced rate, from 5 to 3% of body weight per day during the culture period. Growth attributes, including final weight, weight gain, specific growth rate, and feed utilisation indices, declined significantly (p < 0.05) with increasing stocking density. The survival rate was noticed to be lower at higher densities. Although biomass was higher at SD 30, physiological and biochemical analyses indicated crowding stress, with increased levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), glucose, cortisol, and antioxidant enzymes. Conversely, serum proteins, lipids, thyroid hormones, and immune markers were decreased with density. Poor digestive enzyme activities in terms of amylase and protease were noticed at higher densities, resulting in lower muscle protein content at SD 30. Haematological parameters like red blood cells (RBC), haemoglobin, haematocrit, and platelets increased with density, whilst white blood cells (WBC) remained unchanged. Water quality parameters remained within optimal ranges with minimal variation between inside and outside the cages. The calculated benefit–cost ratio was highest at SD 10 (1.38). Correlation analysis and Integrated Biomarker Response (IBR) indices confirmed density-induced stress, identifying 10 fish/m3 as the optimal stocking density for Amur carp in tropical Indian reservoir cage culture. These findings support evidence-based management strategies that enhance fish welfare and farmer profitability whilst minimising ecological impacts, thereby promoting responsible aquaculture and advancing sustainable food production in line with global Sustainable Development Goals (SDGs).

A futuristic food was developed from farmed shrimp by incorporating a polycationic polymer and natural spices (ginger, garlic & pepper). This study investigates the feasibility of adding varying concentrations of chitosan gel (0, 0.125 %, 0.25 %, 0.375 %, and 0.50 % (w/w)) in combination with a natural spice blend to create a ready-toserve, sous-vide shrimp with enhanced functional properties. The control group showed decreased carotenoid concentration (7.60 mu g/g) compared to the chitosan-treated group (8.66-12.82 mu g/g). Chitosan coating decreases water loss through the ionic interaction with proteins and protects the structural integrity. As the concentration of chitosan increased, the drained meat content and cooking yield also increased. Redness (3.79) and yellowness (9.77) were higher in the chitosan treatment groups than in the control group (2.86 and 6.85). On the other hand, compared to the treatment group, the control group had a greater lightness (L*) score (67.34). The chitosan-coated sample exhibited compact structural integrity and narrow voids compared to the control sample. The substantial intensity absorption of IR spectrum bands revealed that amide I, amide II, and amide III were connected with bioorganic entities (proteins, peptides). The initial mesophilic and psychrophilic bacterial counts for all treatments, including the control, were <2 (log cfu / g), indicating the safety of the product. Sensory evaluation of sous-vide shrimp showed that chitosan incorporation had better flavour retention. The study concluded that adding chitosan and spices (T2-0.25 %) increased the product's water-holding capacity, color, texture, and overall sensory score, leading to feasible and healthy ready-to-serve shrimp products for the seafood sector.

Ecytonucleospora hepatopenaei (EHP), a eukaryotic microsporidian parasite, causes huge economic losses in many shrimp-farming nations. However, effective prophylactics and therapeutics for EHP management are very limited. In this study, a phytobiotic-based therapeutic was found to be effective in controlling EHP and was named 'CIBA EHP Cura I' (Cura). Drugs such as metronidazole (Met), tinidazole (Tin), albendazole (Alb), nifedipine (Nif), ketoconazole (Ket), verapamil (Ver), and plant derivatives such as carvacrol (Car) along with Cura were evaluated against EHP. Though all the drugs significantly reduced EHP load, they cause severe necrosis, degeneration and black discolouration in shrimp hepatopancreas except for Cura. While, the shrimp fed with Cura showed a largely normal hepatopancreas without any degenerative changes. Also, all the other drugs except Cura largely failed to increase the growth and survival of shrimp. At 0.1 %, the Cura was found to completely inhibit the EHP spore germination in vitro. In further experiments, the EHP-challenged shrimp (n = 25 in triplicate) were fed with feed top coated with Cura (0.05 %, 0.1 %, 0.15 % and 0.2 %) and reared for 60 days. The shrimp group fed with Cura at 0.1 %, 0.15 % and 0.2 % exhibited significantly higher innate immune activity (catalase, phenol oxidase and total haemocyte count) and significantly higher weight gain and survival rate. Cura, at 0.15 %, exhibited higher performance across all the treatments. Cura showed strong binding affinity with multiple targets such as SWP, ADP/ATP carrier, protein kinase, and endochitinase of EHP in silico. Additionally, Cura demonstrated potent antibacterial activity against Vibrio parahaemolyticus. Thus, this study highlights Cura, as a promising phytobiotic-based therapeutic for the effective EHP management.