Silver Carp Research Articles

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

AbstractBehavioral 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.

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.

Electrospun fiber mats based on chitosan-carrageenan containing Malva sylvestris anthocyanins: Physic-mechanical, thermal, and barrier properties along with application as intelligent food packaging materials

This study aimed to encapsulate Malva sylvestris extract (MSE) into chitosan-carrageenan (CH-KC) fibers using the electrospinning technique and monitor the freshness of silver carp fillets during the refrigerated storage conditions for 8 days. The CH-KC + MSE 4 % fiber mats were red at pH values lower than 3, purple at pH 4–6, dark blue at pH 7, green at pH 8–10, and brown at pH 11–12. The tensile strength, elongation at break, water vapor permeability, oxygen transmission rate, moisture content, and water solubility of fabricated fiber mats were 7.71–11.02 MPa, 13.12 %–30.00 %, 7.35–20.01 × 10−4 g mm/m2 h Pa, 3.81–8.23 cm3/m2 h, 15.74 %–27.34 %, and 3.90 %–7.56 %, respectively. Regarding the potential application of a fabricated indicator for freshness monitoring of silver carp fillets, total viable count, psychrotrophic bacterial count, pH, and total volatile basic nitrogen reached 8.91 log CFU/g, 8.03 log CFU/g, 8.10, and 40.18 mg N/100 g at the end of the study, respectively. Meanwhile, the CH-KC + MSE 4 % fiber mat color changed from white to green. These findings suggest that CH-KC + MSE 4 % fiber mats can be further utilized in the food industry to control the freshness of refrigerated silver carp fillets.

A Study on the Fresh Water Fish Diversity of Mora Dhansiri River, Assam, India

The Mora Dhansiri River, situated in Darrang District, Assam, India, harbors a diverse array of freshwater fish species, contributing significantly to the region's biodiversity. Through comprehensive sampling efforts, this study identified a total of 29 fish species across 05 orders and 12 families. Cypriniformes dominated the catch list with 17 species, followed by Perciformes with 04 species, Siluriformes with 05 species, Synbranchiformes with 02 species, and one species from Gobiiformes. The most abundant family was Cyprinidae, comprising 22 species, followed by Bagridae and Cobitidae with four species each. The study revealed prominent genera such as Labeo, Puntius, Mystus, and Channa, with multiple species representing each genus. Notably, the presence of exotic species such as Cyprinus carpio, Ctenopharyngodon idella, and Hypophthalmichthys molitrix underscores the influence of adjacent private ponds on the river's fish diversity. Of the recorded species, 19 were deemed edible and suitable for aquarium trade, with three species also possessing medicinal value. Furthermore, the study assessed the conservation status of the fish species, revealing that 2.19% were endangered, 4.54% vulnerable, and 6.81% near-threatened, while 77.2% were categorized as least concern. Additionally, 2.27% of species were classified as data deficient, and 9.09% were not accessed. The presence of near-threatened species like Hypophthalmichthys molitrix highlights the conservation significance of the Mora Dhansiri River. However, anthropogenic pressures such as industrial effluents, pesticide use, overexploitation, and habitat destruction pose significant threats to the river's aquatic biodiversity. Urgent conservation measures are needed to safeguard these valuable resources and ensure their sustainable management for future generations.

Stabilizing effect of silver carp myofibrillar protein modified by high intensity ultrasound on high internal phase emulsions: Protein denaturation, interfacial adsorption and reconfiguration

This study evaluated the impact of high intensity ultrasound (HIU) on myofibrillar proteins (MP) from silver carp, and investigated the stabilizing effect of HIU-treated MP (UMP) on high internal phase emulsions (HIPEs). Ultrasonic cavitation induced protein denaturation by decreasing size and unfolding conformation, to expose more hydrophobic groups, particularly UMP at 390 W, showing the smallest particle size (181.71 nm) and most uniform distribution. These structural changes caused that UMP under 390 W exhibited the highest surface hydrophobicity, solubility (92.72 %) and emulsibility (115.98 m2/g and 70.4 min), all of which contributed to fabricating stable HIPEs with oil volume fraction up to 0.8. UMP-based HIPEs possessed tightly packed gel network and self-supporting appearance due to the adsorption of numerous proteins at the oil-water interface and the reduction of interfacial tension by protein reconfiguration. The larger interface coverage reinforced cross-linking between interfacial proteins, thus increasing the viscoelasticity and recoverability of HIPEs, also the resistance to centrifugal force, high temperature (90 °C, 30 min) and freeze-thaw cycles. These findings furnished insightful perspectives for MP deep processing through HIU, expanding the high-value application of UMP-based HIPEs in fat replacer, nutritional delivery system with high encapsulation content and novel 3D printing ink.

Organophosphorus flame retardants in fish from the middle reaches of the Yangtze River: Tissue distribution, age-dependent accumulation and ecological risk assessment

Two fish species from the middle reaches of the Yangtze River, China, were sampled to investigate the occurrence, tissue distribution, age-dependent accumulation and ecological risk assessment of 24 organophosphorus flame retardants (OPFRs). Seventeen OPFRs were detected in tissue samples with a total concentration ranging from not detected (ND) to 1092 ng g−1 dw. Cl-OPFRs were predominant in all tissues (mean: 145 ng g−1 dw, median: 72.9 ng g−1 dw) and the concentrations of OPFRs in brain were the greatest (crucian carp: 525 ng g−1 dw, silver carp: 56.0 ng g−1 dw) compared with the other three organs (e.g., liver, muscle and gonad). Furthermore, the total concentrations of OPFRs in crucian carp tissues were significantly greater than those in silver carp (P < 0.01). Age-dependent accumulation of OPFRs was observed in the two fish species, but the accumulation profiles in the two fish species were different. Ecological risk assessment demonstrated that both fish species were at medium to high risk, and TDCIPP was a main contributor (>50%).

Effect of Potentilla anserina L. powder on gel properties and volatile flavor characteristics of silver carp surimi.

Potentilla anserina L. is rich in various nutrients, active ingredients and unique flavor, comprising a natural nutrition and health food. However, its application in aquatic food has been rarely reported. Therefore, the effects of Potentilla anserina L. powder (PAP) on gel properties and volatile flavor profile of silver carp surimi were investigated. The gel strength and water-holding capacity of the surimi gels were significantly improved (P < 0.05), and the whiteness and cooking loss of all the samples decreased slightly with the increase in PAP content. The addition of PAP shortened the relaxation time (T2 ) of the surimi gels and converted some of the free water into immobile or bound water, which resulted in a better immobilization of water in the surimi. Scanning electron microscopy images demonstrated that the network of surimi gels with PAP added was denser and had a smoother surface compared to the control. Volatile components (VCs) analysis showed that 33 VCs were identified in the surimi gel samples with different additions of PAP, among which aldehydes, alcohols and esters were the major VCs, accounting for more than 50% of the VCs in the surimi gels. PAP addition reduced the fishy and rancid flavor compounds in surimi gels, such as 1-propanol, 1-octen-3-ol, etc., and promoted the production of aldehydes, alcohols, esters and other flavor substances. These results of the present study provide theoretical support for the investigation and development of new nutrient-health-flavored surimi products. © 2024 Society of Chemical Industry.

Lipid Metabolic Disorders Induced by Organophosphate Esters in Silver Carp from the Middle Reaches of the Yangtze River.

The Yangtze River fishery resources have declined strongly over the past few decades. One suspected reason for the decline in fishery productivity, including silver carp (Hypophthalmichthys molitrix), has been linked to organophosphate esters (OPEs) contaminant exposure. In this study, the adverse effect of OPEs on lipid metabolism in silver carp captured from the Yangtze River was examined, and our results indicated that muscle concentrations of the OPEs were positively associated with serum cholesterol and total lipid levels. In vivo laboratory results revealed that exposure to environmental concentrations of OPEs significantly increased the concentrations of triglyceride, cholesterol, and total lipid levels. Lipidome analysis further confirmed the lipid metabolism dysfunction induced by OPEs, and glycerophospholipids and sphingolipids were the most affected lipids. Hepatic transcriptomic analysis found that OPEs caused significant alterations in the transcription of genes involved in lipid metabolism. Pathways associated with lipid homeostasis, including the peroxisome proliferator-activated receptor (PPAR) signal pathway, cholesterol metabolism, fatty acid biosynthesis, and steroid biosynthesis, were significantly changed. Furthermore, the affinities of OPEs were different, but the 11 OPEs tested could bind with PPARγ, suggesting that OPEs could disrupt lipid metabolism by interacting with PPARγ. Overall, this study highlighted the harmful effects of OPEs on wild fish and provided mechanistic insights into OPE-induced metabolic disorders.

Biometric analysis of food products of hybrid hypoophthalmichthys (Hypophthalmichthys spp.) to determine their nutritional value and use in the food industry

This scientific work describes research, the purpose of which was to study the spectrum of nutrition and the composition of the food lump, as studies aimed at assessing specific weight (%) of essential nutrients (glycogen, proteins, and lipids) in particular organs and tissues of different size and mass groups of the hybrid of Silver carp and Bighead carp in ponds and reservoirs in different periods of the year. In 2018, and 2019, the juveniles of the hybrid of Silver carp and Bighead carp in ponds and reservoirs mainly consumed phytoplankton organisms (from 30 to 90% by mass), among which green, diatom, and euglena algae predominated by mass in the food group. Zooplankton occupied an insignificant place in fish nutrition (up to 5%), even though its quantity and biomass were sufficient in reservoirs. The hybrid of Silver carp and Bighead carp does not hurt zooplankton communities, so it can be included in the stocking volume of Silver carp. The feeding spectrum and rations of different groups of Silver carp and Bighead carp in ponds and reservoirs had a well-defined seasonal character related to the composition of feed objects. In all size and mass groups of the hybrid of silver and bighead carp from ponds and reservoirs in 2018, and 2019, mostly satisfactory values of general metabolism indicators were found – glycogen, proteins, and lipids in the liver, gills, and muscles of fish. The difference found in the availability of essential nutrients in the body of the studied fish indicates a change in the intensity and direction of their metabolic processes.

Comparisons of oxbow lake fish assemblages in relation to bigheaded carp establishment in the lower White River, Arkansas

BackgroundSince the late 1990s, bigheaded carps (largely silver carp [Hypophthalmichthys molitrix] but also bighead carp [H. nobilis]) have established throughout the lower Mississippi River basin. Using previously studied oxbow lakes in the lower White River basin, Arkansas, we compared current (2017, “post-carp” establishment) fish assemblages to historical (2002, “pre-carp” establishment) fish assemblages. Fish assemblages were comprehensively assessed using multiple gears, including boat electrofishing, mini-fyke nets, and experimental small-mesh gill nets.ResultsT-tests suggested that fish assemblage indices of richness, diversity, evenness, and dominance were often greater (P < 0.05) during the post-carp period as reflected by boat electrofishing and experimental gill nets. However, all indices were generally similar (P > 0.05) between the pre-carp and post-carp period with fish assemblages depicted using mini-fyke nets. Nonmetric multidimensional scaling analyses indicated that fish assemblages differed structurally between pre-carp and post-carp periods. Assemblage differences were linked to both small and large abundance changes for more than 20 species. Abundances of gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides), pugnose minnow (Opsopoeodus emiliae), crappies (Pomoxis spp.), bluegill (Lepomis macrochirus), orangespotted sunfish (L. humilis), and yellow bass (Morone mississippiensis) declined between the pre-carp and post-carp periods. Conversely, abundances of weed shiner (N. texanus), pallid shiner (Hybopsis amnis), longear sunfish (L. megalotis), buffalofishes (Ictiobus spp.), and gars (Lepisosteus spp.) generally increased during the same period.ConclusionsAlthough not possible to conclude assemblage shifts were entirely related to bigheaded carps due to the absence of an appropriate reference system where carps did not establish, the wide establishment of these carps is one of the most pervasive changes to have occurred in the lower White River ecosystem during the past two decades. Thus, it is probable to conclude that post-carp establishment observations from this study were at least, in part, attributable to bigheaded carp establishment. Impacts of further range expansions by bigheaded carps in the White River and other lower Mississippi River sub-basins are unclear, though this study suggests probable effects on native fish assemblages, underscoring the need for further research and monitoring.

Impact of Corn Starch Molecular Structures on Texture, Water Dynamics, Microstructure, and Protein Structure in Silver Carp (Hypophthalmichthys molitrix) Surimi Gel.

This study systematically investigates the impact of corn starch molecular structures on the quality attributes of surimi gel products. Employing molecular analyses to characterize corn starch, three amylopectin fractions (A, B1, and B2), categorized by the degree of polymerization ranges (6 < X ≤ 12, 12 < X ≤ 24, and 24 < X ≤ 36, respectively) were specifically focused on. The surimi gel quality was comprehensively assessed through texture profile analysis, nuclear magnetic resonance, scanning electron microscopy, stained section analysis, and Fourier transform infrared spectroscopy. Results indicated the substantial volume expansion of corn amylopectin upon water absorption, effectively occupying the surimi gel matrix and fostering the development of a more densely packed protein network. Starch gels with higher proportions of A, B1, and B2 exhibited improved hardness, chewiness, and bound water content in the resultant surimi gels. The weight-average molecular weight and peak molecular weight of corn starch showed a strong positive correlation with surimi gel hardness and chewiness. Notably, the secondary structure of proteins within the surimi gel was found to be independent of corn starch's molecular structure. This study provides valuable insights for optimizing formulations in surimi gel products, emphasizing the significance of elevated A, B1, and B2 content in corn starch as an optimal choice for crafting dense, chewy, water-retaining surimi gels.

Dual enhancement effects of different yeast extract on gel properties and saltiness perception of low-salt surimi gel from silver carp

This study investigated the dual enhancement effect of five yeast extracts (YE) on gel properties and saltiness perception of low-salt (1% NaCl) surimi gels. The addition of YE not only pronouncedly enhanced the gel strength, texture properties (hardness, cohesiveness and chewiness) and elasticity of low-salt surimi gel (P < 0.05), but also increased the gelation rate of surimi during kamaboko stage. When YE was added, the water holding capacity of surimi gels increased, accompanied by decreased water fluidity, and composite gels exhibited a relatively dense and ordered microstructure. Electronic tongue analysis indicated that YE addition enhanced umami and saltiness, and decreased the sour and bitterness characteristic values (P < 0.05). Besides, sensory evaluation showed that YE increased the texture, saltiness, umami and smell score of low-salt surimi gel (P < 0.05), and the saltiness perception of low-salt surimi gel added with YE1 and YE2 was similar to normal-salt surimi gel (2% NaCl), which was consistent with the result of electronic tongue. The correlation analysis result revealed that the enhancement of gel properties of surimi may be attributed to the charged amino acids (Arg, Lys, His, Glu and Asp) in YE, and the umami substances (Glu, Asp, IMP and GMP) in YE could not only improve the umami taste, but also enhance the saltiness perception of low-salt surimi gel. Overall, YE had the dual effect of remarkably improving the gel properties and enhancing saltiness perception of low-salt surimi gel, providing a salt reduction effect, with YE2 being the best.

Extreme olfactory sensitivity of silver and bighead carp to overlapping suites of 21-carbon steroids suggests that these species, and likely all other Cyprinoidei, employ them as pheromones

Although well established that several fishes including goldfish in the suborder Cypinoidei within the family Cypriniformes use the maturation-inducing steroid 17,20β-dihydroxy-pregn-4-ene-3-one (17,20βP) and its metabolites as a priming pheromone which they detect with sensitivity and specificity, it is unclear whether and how other Cypriniformes might have evolved to do so. This study examined this question in the family Xenocyprididae. Using electro-olfactogram recording we tested the olfactory sensitivity of silver (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) to a range of 213 steroids in 21 mixtures at 10-9M. While silver carp detected 6 of 21 mixtures, bighead carp detected 5 (p< 0.05). Silver carp were sensitive to 13 21-carbon steroids in these mixtures including 17,20βP while bighead carp detected 9, including 8 detected by silver carp. This assortment of steroids overlapped that detected by goldfish (family Cyprinidae) but no non-Cyprinoid, suggesting common evolutionary origin and function with differences characteristic of species-specificity.

Effects of different pH values and monovalent/divalent cations in washing on the physicochemical characteristics of silver carp surimi gel

The objective of this study was to investigate the gel strength, chemical interactions, water distribution, SDS-PAGE and rheological characteristics of surimi washed with different pH values and monovalent/divalent cations. There was higher gel strength in surimi washed with monovalent cations at pH 3.0 or 7.0 and divalent cations at pH 3.0 or 9.0. More divalent cations in the washing delayed surimi protein denaturation. Myosin heavy chain and actin were more intense in surimi washed with 0.25% Na+ or 0.5% other cations. The gel relaxation time was shortened in surimi washed with an increased ionic strength. The gel disulfide bond was decreased in surimi washed at pH 3.0 or 9.0, whereas hydrophobic interactions and ionic and hydrogen bonds were increased in those at pH 5.0 or 7.0. In general, washing with different pH values and monovalent/divalent cations could significantly influence the gel network structure of surimi.

Glycation combined with phosphorylation: Investigating the structure changes and allergenic potential of parvalbumin in silver carp (Hypophthalmichthy molitrix)

This study investigated the effects of glycation combined with phosphorylation on the structure and allergenic potential of parvalbumin (PV) in silver carp (Hypophthalmichthy molitrix). The method increased PV's molecular weight and altered its structure. In vivo, this approach significantly reduced the risk of PV allergy, with decreased serum levels of IgE, IgG, histamine, β-hexosaminidase, and interleukin-4 decreased, while interferon-γ levels increased. Spleen tissue demonstrated increased expression of transforming growth factor-β, interleukin-12, and T-bet. Although the relative abundance of allergy-associated gut microbiota (Firmicutes and Bacteroidetes) changed, the diversity and composition of the gut microbiome in mice remained similar to normal mice at the family and genus taxonomic levels. Allergic mice exhibited imbalanced gut microbiota including Firmicutes, Lactobacillaceae, Staphylococcaceae, and Lactobacillus. Norank_f__Muribaculaceae and Bacteroidetes helped alleviate the allergenic potential. Therefore, glycation combined with phosphorylation can significantly reduce the risk of PV allergy through structural changes and regulation of the gut microbiome.

Progression along the invasion curve: silver carp growth slows temporally in two Missouri River tributaries

Silver carp (Hypophthalmichthys molitrix Valenciennes, 1844) have been invading North American rivers for decades, often altering zooplankton community structure and impacting native fishes. Silver carp invaded eastern South Dakota tributaries of the Missouri River in the early 2000s. Changes in dynamic rate functions can occur as invasive populations move to the latter stages of the invasion curve, but direct temporal assessments of silver carp populations are limited. Our objectives were to compare current growth of silver carp 1) between the Big Sioux and James rivers in South Dakota and 2) with previous growth recorded from the early stages of invasion (2009–2012) in these rivers. We collected silver carp in May and June of 2020–2022 using boat electrofishing and cast netting. We extracted lapilli otoliths for consensus aging from 99 and 82 silver carp from the Big Sioux and James rivers, respectively. We evaluated growth for each population using Bayesian von Bertalanffy models and compared posterior mean length at ages 2–5 to determine the probabilities of differences between rivers and with estimates from the introduction stage. Posterior estimated mean L∞ values were similar between the Big Sioux (714 mm) and James rivers (709 mm); however, the probability that the posterior mean K estimate was greater for silver carp in the James River (0.271) than the Big Sioux River (0.248) was &amp;gt;99.9%. Estimated mean lengths at age 2 were larger in the Big Sioux and James samples than during the introduction stage, but mean lengths at ages 3–5 were smaller. Changes in growth characteristics indicate that growth has slowed in the current establishment stage of invasion from the earlier introduction stage.