Silver Carp Research Articles

Edible Paper Sheets from Alternanthera philoxeroides and Hypophthalmichthys molitrix: Smart Biomass Valorization

Alternanthera philoxeroides and Hypophthalmichthys molitrix offer significant nutritional benefits. This study evaluates the proximate composition, amino acid profile, GC-MS analysis, FT-IR spectroscopy, SEM and EDX, and color values of edible paper sheets (EPSs) derived from Alternanthera philoxeroides incorporating different levels of Hypophthalmichthys molitrix flesh. The protein content in the EPSs varied based on fish flesh incorporation, peaking at 52.66% in Ap100/Hm300 (Non-boil). Protein and carbohydrate contents showed an inverse correlation across EPSs, with the highest carbohydrate content of 60.89% in sample Ap400/Hm0 (Boil). Lipid content was also found to correlate with H. molitrix flesh content in EPSs, ranging from 1.59% to 18.41%. Amino acid analysis identified 11 types, with methionine as the most prevalent, followed by leucine, phenylalanine, and lysine. GC-MS analysis revealed 51 bioactive compounds, including carbonic acid, hentriacontane, and various fatty acids. FT-IR analysis showed characteristic bonds, while color analysis displayed L* values ranging from 24.37 to 30.97. SEM analyses depicted the microstructure, surface view, and elemental composition of the EPSs, and EDX showed an abundance of Ca, N, K, O, C, Mg, Na, P, Cl, Mn, and Fe. Therefore, EPSs prepared from A. philoxeroides and H. molitrix could offer a promising approach for effectively utilizing aquatic biomass and providing both plant and animal nutrients to consumers.

Structural and aggregation changes of silver carp myosin induced with alcohols: Effects of ethanol, 1,2-propanediol, and glycerol

This study investigated the effects of ethanol, 1,2-propanediol, and glycerol on the structure and aggregation behavior of silver carp (Hypophthalmichthys molitrix) myosin. All alcohols induced extensive alteration in the tertiary structure of myosin. Both ethanol and 1,2-propanediol further promoted an increase in the content of β-sheets in myosin and induced myosin aggregation. While glycerol had almost no impact on the secondary structure of myosin. Molecular dynamics simulations revealed that increasing the concentration of ethanol and 1,2-propanediol affected the overall structural changes in the myosin heavy chain (MHC), while glycerol exerted a more pronounced effect on the MHC tail when compared to the MHC head. Disruption of the hydration layers induced by ethanol and 1,2-propanediol contributed to local structural changes in myosin. Glycerol at a concentration of 20% induced the formation of a larger hydration layer around the MHC tail, which facilitated the stabilization of the protein structure.

Effects of different protein cross-linking degrees on physicochemical and subsequent thermal gelling properties of silver carp myofibrillar proteins sol subjected to freeze-thaw cycles

Knowledge regarding the denaturation process and control methods for depolymerized sol-state myofibrillar proteins (MPs) during freezing remains scant. This study investigated the effects of protein cross-linking treatment before freezing on physicochemical and subsequent gelation properties of MPs sol subjected to freeze-thaw (F-T) cycles. Results indicated that after five F-T cycles, cross-linked MPs sols showed increased high molecular weight polymers and bound water (T21a and T21b) mobility, suggesting enhanced protein-protein interactions at the expense of protein-water interactions. Upon heating after F-T cycles, gels formed from cross-linked sols exhibited significantly higher hardness, springiness, and cooking loss (P < 0.05), alongside more contracted gel networks. Correlation analysis revealed that the formation and properties of thermal gel after freezing closely relate to changes in molecular conformation and chemical bonds of cross-linked MPs sol during freezing. This study provides new insights into regulating the freezing stability and post-thawed thermal processing properties of sol-based surimi products.

Algal blooms exacerbate cadmium/zinc bioaccumulation in filter-feeding fish in contaminated water: Mechanisms and environmental implications

Eutrophic waters experiencing cyanobacterial blooms often contain high levels of heavy metal pollutants, including cadmium (Cd) and zinc (Zn). The transfer mechanisms of Cd and Zn within the water-algae-fish system, however, remain poorly understood. This study investigates the accumulation and transfer of Cd and Zn in a simulated water-algae‑silver carp (Hypophthalmichthys molitrix) ecosystem during Microcystis aeruginosa (M. aeruginosa) blooms. Algae demonstrated significant bioaccumulation of Cd and Zn, with Zn proving more toxic to the algae than Cd. In silver carp, the accumulation of Cd and Zn was strengthened in the intestine, liver, and skin following ingestion of M. aeruginosa enriched with these metals. This resulted in a 31% increase in Cd enrichment in the intestine, liver, and a 72% increase in the skin, compared to systems without M. aeruginosa. Zn enrichment in the liver and skin increased by 53% and 61%, respectively. However, muscle accumulation of Cd and Zn showed only minor increases of 0.59 and 3.93 mg/kg. This study elucidated that algae exacerbated the bioaccumulation of Cd and Zn in silver carp through mechanisms such as digestion, absorption, and skin mucosal contact in ecosystems experiencing M. aeruginosa blooms. The accumulation and food chain amplification of heavy metals in eutrophic water bodies increase the ecological toxicity risk to aquatic organisms and local residents. Measures should be considered to simultaneously control both eutrophication and heavy metal pollution in water bodies, with overall results contributing to the scientific management of eutrophic waters containing heavy metals.

Exploring the optimal integrated multi-trophic aquaculture (IMTA) patterns benefiting culture animals and natural water environment

Despite bringing various benefits, rapid developments in aquaculture have contributed to the eutrophication of natural water environments. Therefore, it is imperative to mitigate nutrient load in natural water bodies while ensuring sustainable development of aquaculture. On the basis, we proposed an integrated multi-trophic aquaculture (IMTA) system, which considered a perfect solution and constructed an optimised IMTA pattern. Silver and bighead carps and freshwater pearl mussels were used as purification organisms. Six experimental groups were established for a land-based enclosure experiment: giant freshwater prawn monoculture group (G); giant freshwater prawn and freshwater pearl mussel polyculture group (GH2); giant freshwater prawn and silver and bighead carp polyculture group (GSB); giant freshwater prawn, freshwater pearl mussel and silver and bighead carp polyculture groups (GSBH1, GSBH2 and GSBH3) in different densities of freshwater pearl mussels. Each group had four replicates. Control of cyanobacterial blooms, productivity index, outputs of total nitrogen and total phosphorus and microbial community composition were studied and compared in different culturing patterns. Results showed that the GSBH1 group had the most obvious comprehensive advantages in the above four aspects (no cyanobacterial bloom occurred; the best comprehensive productivity index of giant freshwater prawn; the abundance of beneficial microorganisms in sediments was the highest; reduced phosphorus emissions in tailwater by 60.34%; the utilisation rates of nitrogen and phosphorus increased by 10.99% and 13.05%, respectively). Even so, however, the GSBH1 group might not be the most optimal IMTA pattern in practice because the mortality rate of the mussels reached 12.33% and the weight gain was −3.66%. Additionally, the presence of freshwater pearl mussel at its lowest density in this experiment had exhibited detrimental impacts on the growth of silver and bighead carps. Therefore, the most optimal IMTA pattern needs to be determined by further research.

Production of fish feed by the aquaponic method

Aquaponics is one of the most efficient agricultural production systems; however, there is limited data on its level of effectiveness. The purpose of the research was to study the germination of wheat grain as aquaponic food for herbivorous fish in an aquaponic installation. The experimental production of aquaponic food for herbivorous fish grown in polyculture (carp, grass carp, black carp, silver carp) was studied by the method of wheat grain germination. In an aquaponic device, you can not only grow plants, but also germinate their seeds before planting in the ground. Water is saturated with oxygen due to continuous flow (3.5% more than in a pool without an aquaponic device). This is a positive factor for the growth of fish and energy savings while reducing the duration of the oxygen generators. In addition, the use of an aquaponic device provides favorable conditions for growing plants and fish with a significant reduction in the cost of installation of structures and a decrease in the cost of its operation. An increase in the germination of wheat grain during its germination in an aquaponic installation by 2.0% was established; increase in the length of sprouts during germination - by 27.5%; root length - by 32.2%; increase in the content of crude protein – by 2.2%; vitamin B2 - by 6.1%; carotene – by 4.6%. Hydroponic feed safety indicators were within the limits of sanitary and hygienic standards. The results of this study for the production of hydroponic feed for herbivorous fish directly in the fish farm show that in the production of valuable fortified vegetable environmentally safe feed, it is advisable to use the aquaponic method using water saturated with nutrients.

The effect of water hardness on the development of embryo and larvae of silver carp (Hypophthalmychthis molitrix)

This study aimed to investigate the effect of water hardness on the fertilization rate, hatching rate, survival rate, and deformity rate of common carp larvae. In the experiment, fertilized eggs of silver carp were incubated in different water hardness levels of 70, 100, 130, 160, &amp; 190 mg CaCO3/L, with a stocking density of 400 eggs/L. The experimental results showed that the fertilization rate was high (78.0 - 79.3%) and did not show significant differences between the treatments (P &gt; 0.05). The hatching rate ranged from 41.0 to 54.0% and larvae stage had the highest survival rate of 54.0% at 70 mg CaCO3/L. The deformity rate of larvae ranged from 5.7 to 74.3% with the lowest observed at the 70 mg CaCO3/L. From the results of the study, it can be assumed that silver carp eggs should be incubated in an aquatic environment with a water hardness of 70 mg CaCO3/L.

Ecological inferences on invasive carp survival using hydrodynamics and egg drift models

Bighead carp (Hypophthalmichthys nobilis), silver carp (H. molitrix), black carp (Mylopharyngodon piceus), and grass carp (Ctenopharyngodon idella), are invasive species in North America. However, they hold significant economic importance as food sources in China. The drifting stage of carp eggs has received great attention because egg survival rate is strongly affected by river hydrodynamics. In this study, we explored egg-drift dynamics using computational fluid dynamics (CFD) models to infer potential egg settling zones based on mechanistic criteria from simulated turbulence in the Lower Missouri River. Using an 8-km reach, we simulated flow characteristics with four different discharges, representing 45–3% daily flow exceedance. The CFD results elucidate the highly heterogeneous spatial distribution of flow velocity, flow depth, turbulence kinetic energy (TKE), and the dissipation rate of TKE. The river hydrodynamics were used to determine potential egg settling zones using criteria based on shear velocity, vertical turbulence intensity, and Rouse number. Importantly, we examined the difference between hydrodynamic-inferred settling zones and settling zones predicted using an egg-drift transport model. The results indicate that hydrodynamic inference is useful in determining the ‘potential’ of egg settling, however, egg drifting paths should be taken into account to improve prediction. Our simulation results also indicate that the river turbulence does not surpass the laboratory-identified threshold to pose a threat to carp eggs.

Effect of total dissolved gas supersaturation on the passage behavior of silver carp (Hypophthalmichthys molitrix) and ya-fish (Schizothorax prenanti) through an experimental vertical slot fishway

Total dissolved gas (TDG) supersaturation caused by flood discharge water poses a threat to vital activities such as migration, foraging, and evasion in fish species upstream of the Yangtze River, which may impair the ability of fish to pass through fishways during the migration period, causing poor utilization of fishways. Previous studies have shown that TDG supersaturation reduces the critical and burst swimming abilities of fish, suggesting potential adverse effects on swimming performance. However, studies focusing on the impact of TDG on fish swimming behavior in experimental vertical-slot fishways remain scarce. Therefore, in this study, silver carp (Hypophthalmichthys molitrix) and ya-fish (Schizothorax prenanti) were used as the study species, and comparative passage experiments were carried out in an experimental vertical slot fishway to systematically analyze the effects of TDG supersaturation on their passage behavior. The passage success of the silver carp was 57%, 39%, 26%, and 27% at TDG levels of 100%, 110%, 120%, and 130%, respectively. Passage success of ya-fish was 73%, 37%, 31%, and 35% at TDG concentrations of 100%, 110%, 120%, and 130%, respectively. The passage time for both species increased significantly with increasing TDG levels. Furthermore, the passage routes of silver carp changed significantly compared to the control group, whereas the passage routes of ya-fish changed insignificantly. High levels of TDG supersaturation (≥120%) also contributed to a higher mortality rate of ya-fish passing through the vertical slot fishway. The research results provide valuable data on the influence of TDG supersaturation on fish movement behavior responses in experimental vertical slot fishways, offering a reference for the design of fishways and the formulation of reservoir operation schemes.

Inhibitive effect of trehalose and sodium pyrophosphate on oxidation and structural changes of myofibrillar proteins in silver carp surimi during frozen storage

This work investigated the cryoprotective effect of trehalose (TH) and sodium pyrophosphate (SPP) alone and in combination on myofibrillar protein (MP) oxidation and structural changes in silver carp surimi during 90 days of frozen storage (-20 °C). TH combined with SPP was significantly more effective than single TH or SPP in preventing MP oxidation (P < 0.05), showing a higher SH content (6.05 nmol/mg protein), and a lower carbonyl (4.24 nmol/mg protein) and dityrosine content (1280 A.U.). SDS-PAGE results indicated that TH combined with SPP did not differ significantly from TH and SPP in inhibiting protein degradation but was more effective in inhibiting protein crosslinking. Moreover, all cryoprotectants could stabilise the secondary and tertiary structures and inhibit unfolded and aggregation of MP, with the combination of TH and SPP being the best. It's worth noting that TH combined with SPP had a synergistic effect on inhibiting the decrease in α-helix content and gel-forming ability, and the increase in surface hydrophobicity. Overall, TH combined with SPP could significantly inhibited MP oxidation and structural changes in surimi during frozen storage and improve the gel-forming ability, which was significantly better than single TH or SPP.

A dual-mode fluorometric/colorimetric sensor for sulfadimethoxine detection based on Prussian blue nanoparticles and carbon dots.

A dual-mode (colorimetric/fluorescence) nanoenzyme-linked immunosorbent assay (NLISA) was developed based on Au-Cu nanocubes generating Prussian blue nanoparticles (PBNPs). It is expected that this method can be used to detect the residues of sulfonamides in the field, and solve the problem of long analysis time and high cost of the traditional method. Sulfadimethoxine (SDM) was selected as the proof-of-concept target analyte. The Au-Cu nanocubes were linked to the aptamer by amide interaction, and the Au-Cu nanocubes, SDM and antibody were immobilized on a 96-well plate using the sandwich method. The assay generates PBNPs by oxidising the Cu shells on the Au-Cu nanocubes in the presence of hydrochloric acid, Fe3+ and K3[Fe (CN)6]. In this process, the copper shell undergoes oxidation to Cu2+ and subsequently Cu2 + further quenches the fluorescence of the carbon point. PBNPs exhibit peroxidase-like activity, oxidising 3,3',5,5'-tetramethylbenzidine (TMB) to OX-TMB in the presence of H2O2, which alters the colorimetric signal. The dual-mode signals are directly proportional to the sulfadimethoxine concentration within the range 10- 3~10- 7 mg/mL. The limit of detection (LOD) of the assay is 0.023 ng/mL and 0.071 ng/mL for the fluorescent signal and the colorimetric signal, respectively. Moreover, the assay was successfully applied to determine sulfadimethoxine in silver carp, shrimp, and lamb samples with satisfactory results.

Assessing Prospects of Integrating Asian Carp Polyculture in Europe: A Nature-Based Solution under Climate Change?

Aquaculture’s role in addressing food security has grown, with a spotlight on Asian carp species. Polyculture, i.e. cultivating multiple fish species in a single system, is being increasingly adopted for its resource efficiency and economic benefits. This practice for Asian fish for food and ornamental purposes is gaining traction in Europe despite their invasive potential. Rising temperatures due to climate change offer an opportunity for thermophilic Asian carps (Hypophthalmichthys molitrix and Aristichthys nobilis). Using GIS modeling (Maxent), we identified the possible settlement of Asian carp in Northern Europe amidst climate change. We analyzed carp global distribution centers, assessed the potential carp spread in Europe, and evaluated their potential suitability for polyculture systems. By 2050, H. molitrix may extend its range to 58–62° N latitude, with a potential 1.7-fold habitat increase, while A. nobilis, which are more heat-tolerant, may move north to 52–58° N latitude, with a 1.3-fold potential increase. Despite the slight ecological differences in their native habitats, niche modeling indicates that these carp can occupy similar niches in Europe (proven statistically). The eventuality of using Asian species for polyculture in Europe presents both opportunities and challenges in the face of a changing climate as long as invasion risks are prevented. Envisaging such polyculture, yet very carefully for the protection of ecosystems, can help food security.

Towards higher-quality low salt surimi gels: Significance of the combinatorial effects of chickpea protein with transglutaminase on their micro-structures

The textural properties of low-salt hybrid gel made from silver carp (Hypophthalmichthys molitrix) and chickpea protein (CPP) with or without external transglutaminase (TGase) were investigated. A decrease in gel strength (P﹤0.01), hardness (P﹤0.01), storage modulus (G′) and loss modulus (G″) of the hybrid gel containing CPP appeared regardless of the addition of TGase. Furthermore, the addition of CPP combining with TGase significantly induced a significantly higher resilience (from 43.5% to 50.3%), cohesiveness (from 0.72 to 0.79), proportion of immobilized water (from 95.7% to 97.4%), number of pores (from 3181 to 4868) and apparent porosity (from 30.55% to 40.26%) than those of the group containing TGase alone, which indicated the combining effect of CPP and TGase on the textural properties. The SDS-PAGE profiles showed that the covalent complex between CPP and myofibrillar proteins was not observed. During the gelation of myofibrillar protein filaments, CPP wrapped the fibres shown by the microstructure morphology and increased the friction between fibres, leading to an increase in relaxation time. TGase promoted this effect and induced the formation of a denser microstructure. The present study provided a feasible approach for the preparation of high-quality low salt surimi products with more favorable texture and acceptability.

Multi-scale effects of behavioral movement deterrents on invasive carp metapopulations

Behavioral deterrents of among-pool movement represent a promising tool for controlling invasive fish populations. To date, much of the research in this area has been focused on the direct effectiveness of different methods of deterrence. However, the effect of these structures on populations in spatially complex habitats is unknown. We combine a metacommunity model with movement data of two invasive species (bighead carp and silver carp) in a large river to assess local and river-wide scale population outcomes of deterrent locations. We calculated (1) which potential deterrent locations are most effective at reducing the growth at the invasion front (2) the river-scale population effects at each location, and (3) what, if any, are the risks imposed by altering the current spatial dynamics. We found that the effects on the population dynamics at the invasion front varied with the location of deterrents, ranging from near zero to effects equal to the reduction in an individual’s movement across the deterrent. The river-scale population growth rate was slightly increased by all potential deterrent placements because the deterrents tended to concentrate more of the river-scale population into pools with the highest recruitment rates. The short-term, transient dynamics followed a strictly decreasing pattern after deterrent placement suggesting no additional short-term risk. These results suggest that deterrents can be an effective and low-risk intervention for the control of invasive carp, although the population level effect will depend on the interaction of the traits and behavior of the species with the physical character and spatial structure of the habitat.

Introducing Copi as a Positive Path Toward Combatting Invasive Carps in North America

A group of loosely related, large‐bodied fishes collectively called carps have had a complex relationship with North Americans. Despite lessons learned about invasive Common Carp Cyprinus carpio in the early 1900s, Bighead Carp Hypophthalmichthys nobilis, Black Carp Mylopharyngodon piceus, Grass Carp Ctenopharyngodon idella, and Silver Carp H. molitrix were introduced to the United States more than 50 years ago and are expanding throughout the Mississippi River basin. Increased economic value in the North American seafood market could aid management. Complete eradication through harvest is unlikely, but controlling densities and containing dispersal may be possible. Improving perceptions of nutrition, palatability, and safety of wild‐caught carps should increase consumer demand. A branding and marketing effort launched in June 2022 renamed the foodstuff produced from the four species as the trademarked brand Copi. The “Choose Copi: Eat Well. Do Good.” campaign allows consumers to know that these fishes are an environmentally sound and responsible alternative to other seafood choices. The Copi brand has gained interest nationwide, with food processors and distributors engaged, although the contribution of Copi to harvest removal from rivers and resulting population dynamics is yet to be quantified. Developing a regional fishing industry for Copi, while also aiding fisheries and aquaculture for native species, remains an economic and logistical challenge within the vast river network.

Enhancing the Quality of Low-Salt Silver Carp (Hypophthalmichthys molitrix) Surimi Gel Using Psyllium Husk Powder: An Orthogonal Experimental Approach.

Low-salt surimi production is crucial as it addresses health concerns related to sodium intake while maintaining the quality and shelf-life of seafood products. This research focused on optimizing the gelation conditions for silver carp surimi with the addition of psyllium husk powder at low salt concentrations (0.5% and 1%, w/w) to investigate the effects of psyllium husk powder concentration, temperature, and time on gel strength and water-holding capacity. The quality was assessed in terms of gel strength and water-holding capacity. Following a single-factor exploration, a three-level orthogonal experiment was designed to evaluate the influence of these three variables using a combined scoring system. Results indicated that psyllium husk powder levels between 0.1% and 0.3% (w/w) enhanced gel strength and water-holding capacity. The optimal conditions were identified as follows: 1% (w/w) NaCl with 0.2% (w/w) psyllium husk powder for 2.5 h at 35 °C, and 0.5% (w/w) NaCl with 0.3% (w/w) psyllium husk powder for 3 h at 35 °C. Texture profile analysis revealed that psyllium husk powder increased the hardness of the surimi gel, promoting myosin cross-linking and denser gel structure. Compared to traditional surimi gel, which relies on ionic bonds, the optimized gel showed higher levels of disulfide cross-linking and enhanced hydrophobic interactions, resulting in a stronger gel structure. Sensory evaluation suggested that surimi gels with psyllium husk powder were perceived as better than those without psyllium husk powder. The study concludes that selecting the appropriate psyllium husk powder quantity and thermal processing conditions based on salt concentration can significantly improve the quality of low-salt surimi gels. Error analysis using one-way ANOVA was performed on all experimental data and (p < 0.05) indicated the significant difference.

Biological indicators and commercial exploitation of main fish and river crayfish species of the Zaporizhzhia (Dnipro) reservoir

Aim: To analyze and summarize the biological indicators of the main industrial fish and river crayfish species in the Zaporizhzhia (Dnipro) reservoir under conditions of fishery exploitation. Methods: Biological analysis of fish was conducted according to classical methods in ichthyology, using the following parameters: standard and absolute body length, individual mass, gender, feeding coefficient. Crayfish, caught in fishing gear, underwent morphometric measurements to determine individual mass and gender. Biological sampling was carried out during the vegetation period of 2023 during both control and commercial fishing in the Zaporizhzhia (Dnipro) reservoir at three sites differing in hydrology and degree of anthropogenic impact. Research results: According to the data from the Department of the State Agency of Reclamation and Fisheries Management in Dnipropetrovsk Oblast, during 2023, 140,504 tons of fish were caught in the Zaporizhzhia (Dnipro) reservoir, nearly 8 times less than in 2021. In 2021, 1078.25 tons of aquatic resources were caught, which is 8 % less than in 2020. Silver carp was the dominant fish species in 2022, accounting for 80.5 % of the total catch in the reservoir. Herbivorous fish species accounted for 5.4 % of the catch, roach - 3.3 %, bream - 2.3 %, perch - 2.0 %. Based on the conducted research, recommendations have been provided regarding the establishment of forecasts and limits for the extraction of aquatic resources from the Zaporizhzhia (Dnipro) reservoir for the year 2024. Conclusions: The Zaporizhzhia (Dnipro) reservoir has potential for the development of fishing, fish farming, and aquaculture in the Prydniprovsky region. The research results suggest that limits can be set on the catch of certain fish species: bream- up to 210 tons, pike-perch - up to 42 tons, roach - up to 350 tons, and perch - up to 138 tons. However, the catch of silver carp, bleak, sprat, herbivorous fish, and sun-perch is recommended to be unrestricted. The forecasted catch of crayfish is within 1 ton. The catch of other aquatic resources should also be conducted within forecasted levels

Characterization of aroma characteristics of silver carp mince glycated with different reducing sugars

The purpose of this study was to investigate the volatile flavor changes in silver carp mince (SCM) gel glycated with different reducing sugars (glucose, L-arabinose, and xylose) based on E-nose, GC-IMS, and sensory evaluation. These results showed that glycation reduced the fishy smell of SCM gel and increased the meaty, toasty, and burnt smell. A total of 10 volatile compounds were considered as characteristic flavor compounds and potential markers. Among them, the main contributors of fishy included hexanal, heptanal, n-nonanal, octanal, etc. Toasty and burnt were mainly related to the production of 3-methylbutanal and furfurol. These results heralded that glycation could be used to improve the volatile flavor of SCM. This research provided a theoretical basis and technical support for glycation in aquatic food flavor quality control, aquatic pre-made food development, and aquatic leisure food processing.

Plastein reaction enhances the emulsifying and rheological properties of silver carp hydrolysates in oil-in-water emulsions

The plastein reaction was ubiquitously acknowledged for its capacity to enhance the functional properties of protein hydrolysates. Despite this, the specific impact of the plastein reaction on emulsification, a critical functional aspect of protein hydrolysates, remains incompletely understood. In this study, the plastein reaction in silver carp protein hydrolysate (SCPH) was explored. A detailed comparison between the primary product (PP) and the blended product (SCPH–P) in terms of their oil-water interfacial adsorption kinetics and the shear strain of oil-in-water emulsions was reported. The interfacial adsorption kinetics suggested that the higher molecular weight imparted a slow rate of diffusion, penetration, and reorganization to the PP compared to SCPH-P. Furthermore, the elevated surface hydrophobicity also resulted in higher surface activity (i.e., high interfacial pressure) for PP. Simultaneously, nonlinear rheological analysis revealed that PP possessed enhanced resistance to shear strain due to its strong affinity for the oil-water interface of emulsion. These improvements manifested in PP-stabilized emulsions with reduced mean particle size (71.6 μm–9.5 μm), diminished instability index (nearly 3-fold prolongation of stabilization time), and increased electrostatic repulsion (zeta potential values increased from 6-15 mV to 21–27 mV), which underscored a substantial enhancement in the emulsification of SCPH through the plastein reaction. Notably, the emulsifying and rheological properties of PP at a 1% (w/w) concentration were nearly equivalent to those of soybean protein isolate at 0.5% (w/w), highlighting the plastein reaction's innovative potential in utilizing SCPH as a promising emulsifier.

Present status of brood stock management and breeding operations at Carp Hatcheries in Jashore, Bangladesh

Sustainable aquaculture production depends on the proper management of brood stock. In this regard, multiple survey studies were reviewed to assess the present status of management of carp brood stock at Jashore region in Bangladesh from March 2023 to August 2023. A total of 38 hatcheries were selected in Jashore. The areas of ponds were ranged from 33.33 to 400 decimal and shape with maximum rectangular. The green color water of pond was 79% and 75% practice pond drying. Most of the farmers applied liming doses were ranged from 500- 1200 gm dec-1. Most of the farmers used rotenone (39%) to control predators in the brood stock pond. Different sorts of fertilizers both organic and inorganic were applied. Most of the brood stocks (39%) were collected from the hatcheries and the rest of them were collected from other pond, World fish, BFRI and the natural sources (Halda and Padma River). Moreover, 4 carp species (rui, catla, mrigala and kalbashu) among 13 endemic and 4 exotic carp species (silver carp, grass carp, bighead and common carp) out of 6 exotic carp’s species were used for seed production. Negative selection of brood stock was performed in few hatcheries in order to reduce the cost for collecting or purchasing good quality broods. The formulated feed which contained 20-30% protein for carp brood stock were prepared using the indigenous ingredients including mainly rice bran, mustard oil cake, vitamin and mineral premix, wheat flour, fish meal and soya bean flour and maize flour. The main problem of hatchling production is Argulosis (fish lice) diseases which causes 95% of hatchlings mortality. Finally, these survey findings indicate that proper brood stock management could be a good approach to attain the main purpose of aquaculture.