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Context. Black soldier fly larvae are a promising alternative ingredient in poultry feed. They might be able to replace soybean and fishmeal because the have high concentrations of protein and fat, and are also rich in vitamins and minerals, and because partial replacement of soybean and total replacement of fishmeal produce no adverse effect on the growth performance of village chickens. Therefore, they are a suitable replacement for these traditional ingredients in poultry feed. Aims. This study determines the nutritive values of black soldier fly larvae and evaluates the effects of feeding diets containing black soldier fly larvae on the growth performance of village chickens. Methods. Samples of black soldier fly larvae were subjected to proximate analysis before a total of 280 1-day-old village chicks were randomly divided into four groups. All groups were fed a basal diet with partial replacements of corn and soybean with black soldier fly larvae at 0% (Control), 5% (T1), 10% (T2) and 15% (T3) for 70 days. Each treatment group consisted of seven replicates, with 10 birds per replicate. The bodyweights, bodyweight gains and feed conversion rates were determined. Key results. Dry rendered black soldier fly larvae contained 773.0 ± 0.08 g/kg dry matter, 36.1 ± 0.09 g/kg ash, 408.8 ± 0.28 g/kg crude protein, 283.0 ± 0.16 g/kg ether extract and 40.9 ± 0.44 g/kg crude fibre. The larvae also contained 2.041 MJ/kg of metabolisable energy, 20.4 g/kg of calcium and adequate concentrations of vitamins. The feeding trial showed an average bodyweight gain of 1231.45 ± 23.37 g and feed conversion ratio of 2.03 ± 0.15, which were most efficient with Diet T3. Conclusions. Inclusion of 15% black soldier fly larvae in diets can enhance the growth performance of village chickens without adverse effects. Implications. Partial replacement of soybean and total replacement of fishmeal in the diet of chickens by black soldier fly larvae are not affecting the growth performance of village chickens but might reduce the feed cost. [ABSTRACT FROM AUTHOR]

The ratio of mortality to growth of larval fish provides a metric of a cohort's "recruitment potential". Estimating recruitment potential is arduous, requiring growth and mortality to be estimated independently. Here, we propose using the exponent of size spectrum models to indicate recruitment potential from body measurement data alone. This approach has several advantages including (1) reducing data collection times, (2) removing uncertainty in estimates generated from age estimation, and (3) allowing re-analysis of larval fish databases or archived collections. To test the validity of this approach, we conduct simulations comparing estimates of recruitment potential from an abundance spectrum model with other common methods. By varying larval flux rates, growth, mortality, and measurement error, we show the abundance spectrum model is more accurate and precise at smaller sample sizes, and more robust to variance in individual rates and measurement error of ages, but more susceptible to measurement error of size. We highlight that a size-based approach to estimating recruitment potential provides another useful tool for understanding larval survival, reducing resource demands on research compared to traditional methods. [ABSTRACT FROM AUTHOR]

Spawning Pacific salmon (Oncorhynchus spp.) provide marine‐derived resources (MDR) to freshwater food webs in the form of eggs, flesh and maggots that consume salmon carcasses, all of which positively impact stream‐dwelling fish growth. Pink salmon (O. gorbuscha) are widely distributed throughout coastal catchments along the North Pacific Ocean and display increased spawning abundances in odd years, owing to a fixed 2‐year life history. While many studies have found that foraging and growth of stream‐dwelling salmonids are improved by increased adult salmon spawning abundance, few studies have investigated the importance of alternating pink salmon spawning abundance between years.Here, we examined how patterns of pink salmon spawning abundance impact the foraging and growth of juvenile coho salmon (O. kisutch). First, we used bioenergetic simulations to generate a hypothesis that coho salmon growth would increase during odd relative to even years. We then collected empirical juvenile coho salmon diet and growth data from a Southeast Alaska catchment in 2021 (pink salmon spawning) and 2022 (no pink salmon spawning). Field data were compared against simulation predictions to understand impacts of biennial pink salmon spawning patterns on juvenile coho salmon growth.Empirical growth data revealed similar patterns to bioenergetic simulations. Age‐1 coho salmon grew 16.6 mm longer and 5.5 g heavier on average in 2021 compared to 2022. Age‐0 coho salmon displayed minor growth differences between years.These results support bioenergetic model predictions and suggest that patterns of pink salmon spawning abundance can impart interannual growth disparities to juvenile coho salmon. Moreover, we show that distinct spawning characteristics of Pacific salmon species are important when understanding patterns of MDR transfer and growth responses in stream fishes. [ABSTRACT FROM AUTHOR]

Pisciculture encounters an array of intricate challenges that span disease management, preservation of water quality, prevention of genetic hybridization, ensuring the integrity of net systems, sourcing sustainable aquatic feed, and comprehending fish growth and reproductive dynamics. Addressing these multifaceted challenges necessitates a comprehensive research approach. This study employs an innovative synergy of fuzzy logic and deep learning techniques, resulting in a robust strategy to tackle these obstacles effectively. Fuzzy logic excels in assessing stressed fish conditions by handling inherent uncertainties. Simultaneously, YOLOv7 with fuzzy color enhancement (YOLOv7FCE) is used to detect damaged fish nets, thereby mitigating losses and upholding the integrity of the net infrastructure. This approach also leverages YOLOv7FCE for identifying Cobia fish within shoals, streamlining the identification process. Subsequently, DeepLabv3 is implemented to meticulously segment the recognized Cobia fish, facilitating precise measurements of their physical attributes. This comprehensive methodology yields profound insights into growth patterns and feeding tendencies within the confined aquatic environment. By embracing this approach, the research presents a versatile and adaptive framework that not only enhances our comprehension of piscine dynamics but also holds the potential to revolutionize the aquaculture industry. [ABSTRACT FROM AUTHOR]

The pomfret fish, particularly the black pomfret (Parastromateus niger), serves as a significant economic resource in South Asia, particularly in the coastal regions of Balochistan, Pakistan. This study investigates various biological parameters of Parastromateus niger collected from the Gaddani coastal area of Pakistan, focusing on length-weight relationships, gut fullness, and population demographics. A total of 117 fish specimens were collected, with females dominating the samples. Length and weight data were analyzed separately for males and females, with statistical calculations revealing strong correlations (r2 values ranging from 0.918 to 0.985) between length and weight for both sexes. Gut fullness was categorized into five levels, with the highest percentage observed during July, suggesting potential breeding activity during this period. The zooplanktons were identified as primary dietary components of Parastromateus niger. The study also highlights the importance of regulatory measures to sustainably manage fish populations, especially during breeding seasons, and calls for further research into the intensive culturing and feeding regimes of black pomfret to enhance its production. Overall, these findings contribute to a better understanding of the biological characteristics and potential for aquaculture development of Parastromateus niger in the region. [ABSTRACT FROM AUTHOR]

Introduction: Investigating and assessing native fish diversity and conducting regional assessments of threats are vital for the conservation of aquatic biodiversity. For this specific study, the Daqing River basin in China was chosen as the research area. Field surveys were carried out between 2018 and 2019, supplemented by a review of pertinent literature and other records. Methods: To evaluate fish diversity, the following parameters are selected for analysis: Relative abundance (Pi), Frequency of occurrence (Fi), Margalef richness index (D), Shannon Wiener diversity index (H'), and Pielou evenness index (J').Relative abundance levels are categorized as follows: dominant species make up more than 10%, common species account for 1%--10%, and occasional species constitute less than 1%. Canoco 5.0 software was utilized to conduct Redundancy Analysis (RDA) on the fish species composition and environmental factors at 34 sampling sites. Results: The findings revealed that 85 fish species have been recorded in the basin, consisting of 78 freshwater species categorized into 8 orders, 17 families, and 59 genera, among which Cypriniformes comprised 64% of the total catch. The low proportion of threatened and endemic species was an important feature of the fish diversity of the Daqing River. Despite the theoretical presence of 85 species, field surveys managed to collect only 42 species, of which 33 were confirmed as naturally occurring within the basin. The average values of Margalef richness index, 22 Shannon Wiener diversity index and Pielou evenness index were 1.72, 2.04 and 0.80 respectively, signifying a low fish diversity with relatively uniform distribution across the sampled regions. Discussion: This study found that the community structure and diversity of fish were closely related to environmental factors, particularly water quality. Among these factors, ammonia nitrogen emerged as a significant determinant of fish diversity. High concentrations of ammonia nitrogen inhibit fish growth, endanger health, and can even lead to death. Additionally, dams and other water infrastructure also impact fish community structure and diversity. This baseline study can provide a basis for the protection and ecological restoration of fish resources in the Daqing River. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is a nutritional element required for fish growth and physiology functions. In this study, we examined the effect of Mn on the intestinal digestive function, antioxidant response, and muscle quality in coho salmon (Oncorhynchus kisutch). Nine hundred salmons with initial weight approximately 0.35 g were fed with six isoproteic and isoenergetic diets formulated to contain 2.4, 8.5, 14.8, 19.8, 24.6, and 33.7 mg/kg Mn for 84 days. The result showed that the activity of trypsin and lipase was elevated, whereas α‐amylase activity was not affected by various Mn diets in intestine. Dietary Mn elevated the activity of Mn‐superoxide dismutase (Mn‐SOD), total superoxide dismutase (T‐SOD), glutathione peroxidase (GSH‐PX), and catalase (CAT), but had no influence on copper/zinc‐superoxide dismutase (Cu/Zn‐SOD) in intestine. Dietary Mn at 8.5, 14.8, 19.8, 24.6, and 33.7 mg/kg enhanced the gene expression level of protein kinase B (Akt) and mammalian target of rapamycin (mTOR). In addition, the accumulation of Mn in muscle was enhanced with increasing levels of dietary Mn. Dietary Mn elevated the content of sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca), but the content of iron (Fe) and Zn was decreased by dietary Mn in the salmon muscle. The content of fatty acids and amino acids was enhanced by various levels of dietary Mn in muscle. Moreover, a significant quadratic effect was observed on the texture of salmon muscle. The dietary Mn requirement was 16.9–25.7 mg/kg Mn to acquire the highest value of muscle texture using the quadratic regression model. The diets at 14.8 and 19.8 mg/kg Mn had a higher score of sensory evaluation for raw muscle. Our result showed that dietary Mn affected the intestinal digestion function and antioxidant response, which may further result in the change of muscle quality in coho salmon. The result will provide reference for detecting the effect of dietary micronutrients on the muscle quality of salmons. [ABSTRACT FROM AUTHOR]

In the 20th centuary, the economically important carp species Labeo rohita, Tor tor, & Labeo calbasu and the catfishes Rita rita & Bagarius bagarius contributed substantially to the total fish catch from the Ganga River system in India. Samples were recorded between December 2003 and June 2004 from fish landing centers in the Ken, Paisuni, and Tons rivers for L. rohita, T. tor and L. calbasu. Rita rita and B. bagarius were sampled between September 2001 and September 2003 in the Ganga River system. The data were used to evaluate the growth and age structures of fish populations. Age classes varied 0+-5+ for L. rohita in the Ken & Paisuni rivers and 0+-8+ in the Tons River. For T. tor, the age classes varied 1+-6+ in the Ken & Paisuni rivers and 1+-8+ in the Tons. Age classes of L. calbasu varied 1+-6+ in the Ken River, 1+-5+ in the Paisuni River, and 1+-7+ in the Tons. In the Ganga River, age classes of R. rita & B. bagarius varied 0+-7+ and 0+-6+, respectively. The L. rohita, age pyramid showed a tendency for bell shape in Ken River, base tends to be broader through bell shape in Paisuni River, and bell-shaped age pyramid was slightly distorted in Tons River. In case of T. tor, tendency for bell shape in Ken River and bell-shaped age pyramid in Paisun River & Tons River were obtained. In case of L. calbasu, heavy bottom shaped age pyramid was recorded in Ken and Paisuni rivers, while base tends to be broader in the Tons River. Bell shaped age pyramid was recorded for B. bagarius in the Ganga River while heavy bottom shape for R. rita in the Ganga River. Overall, T. tor is facing heavy fishing pressure and also targeted fish species by fishermen from the Ganga River system. [ABSTRACT FROM AUTHOR]

The use of fish meal/oil in carnivorous fish feeds remains a concern for the environmental sustainability of aquaculture. In this study, we investigated the impact of an innovative diet designed to be cost‐effective and environmentally sustainable (i.e., 60% replacement of fish meal by a blend of plant, yeast [Saccharomyces cerevisiae], and krill meal feed ingredients) on the growth, health, and welfare of gilthead seabream (Sparus aurata). Over a 135‐day experiment, fish were fed either the innovative or a commercial diet (control), and various parameters were evaluated, namely growth performance, levels of physiological blood parameters related to stress, immunity, health, and welfare, as well as swimming activity, serving as a proxy for energy expenditure. Results revealed that the innovative diet enhanced growth compared to fish fed the control diet. Hematological and biochemical indicators did not highlight any impaired welfare condition in fish fed innovative diet while higher levels of Immunoglobulin M were measured in plasma of fish fed innovative diet, potentially suggesting enhancement of humoral immunity. However, accelerometer tags data revealed that fish fed the innovative diet exhibited higher overall swimming activity, suggesting higher energy expenditure, which was consistent with greater prealbumin levels measured in the plasma. In conclusion, the higher energy metabolism in fish fed the innovative diet might be compensated by the diet's content, which may boost humoral immunity and hence help the fish develop a better adaptation to rearing environment, including its viral and bacterial load, ensuring overall better growth. Longer term investigations, including measurements of additional parameters, are required to validate these promising preliminary outcomes. [ABSTRACT FROM AUTHOR]

The significant role played by the gut microbiota in fish growth, development, immunity, and overall health has been widely established. Nevertheless, there remains a lack of clarity regarding the interaction and origin between the environmental microbiota and the gut microbiota of aquaculture species within the aquaponics coupling system. Thus, we conducted an analysis of the gut microbiota of largemouth bass (Micropterus salmoides) obtained from an indoor enclosed circulating water aquaponics coupling system located in greenhouses in northern China. Additionally, we examined the microbiota of the fish pond water and tomato rhizosphere soil using high-throughput sequencing of the 16S rRNA gene. Our results demonstrated significant differences in the compositions of fish pond water, rhizosphere soil, and the gut microbiota of largemouth bass. Moreover, these compositions changed throughout the culture period. Approximately 11.99% of the bacterial composition in the gut microbiota of largemouth bass could be attributable to the rhizosphere soil microbiota, while 62.01% of the bacterial composition could be attributable to the fish pond water microbiota. However, the proportion of bacteria in the gut microbiota from the fish pond water microbiota remained respectively 40.90% and 56.15% in May and September, which increased markedly to 88.97% in July. Similarly, the proportion of bacteria in the pond water microbiota from the tomato rhizosphere soil microbiota were respectively 0% and 8.95% in samples collected in May and September, which increased markedly to 69.26% in July, and the proportion of bacteria in the gut microbiota from the tomato rhizosphere soil microbiota were respectively 0.07% and 0% in samples collected in May and September, which increased to 0.45% in July. The research results offer essential insights into the interactions and origins of environmental microbiota and gut microbiota in the aquaponics system of cultured fish. This knowledge could enhance green aquaponics practices for largemouth bass. [ABSTRACT FROM AUTHOR]

The hybrid grouper (Cromileptes altivelas, ♀ × Epinephelus lanceolatus, ♂) is an economically important aquaculture species that exhibits certain growth advantages compared to its female parent, Cromileptes altivelas. However, the current understanding of the molecular mechanisms underlying the growth of hybrid groupers is lacking. Herein, we performed full-length transcriptome sequencing and next-generation sequencing on the hybrid grouper and its parents to identify growth-related genes and comprehensively analyze the regulatory mechanism of growth heterosis in the hybrid grouper. Approximately 44.70, 40.44, and 45.32 Gb of single-molecule real-time sequencing data were generated in C. altivelas (Cal), E. lanceolatus (Ela), and the hybrid (Hyb), which were combined into 204,322 non-redundant isoforms using the PacBio sequencing platform. Differentially expressed genes (DEGs) were identified between Hyb and Cal (3,494, 2,125, and 1,487 in brain, liver, and muscle tissues, respectively) and Hyb and Ela (3,415, 2,351, and 1,675 in brain, liver, and muscle tissues, respectively). Then, 27 DEGs (13 in the brain and 14 in the muscle) related to growth traits were identified using cluster and correlation network analysis. Quantitative RT-PCR validated 15 DEGs consistent with transcriptome sequencing (RNA-seq) trends. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these 15 genes were mainly involved in regulating the actin cytoskeleton, suggesting that this pathway plays an essential role in fish growth. In addition, we found that the phosphatase and tensin homologue (PTEN) is a key regulator of growth heterosis in Hyb. These results shed light on the regulatory mechanism of growth in the Hyb, which is important for marker-assisted selection programs to improve the growth quality of groupers. [ABSTRACT FROM AUTHOR]

Background: Our previous study revealed that feeding the antimicrobial peptide (AMP) product Scy-hepc significantly enhances the growth of mariculture fish through the activation of the GH-Jak2-STAT5-IGF1 axis. However, the contribution of gut microbiota to this growth enhancement remains unclear. This study aimed to elucidate the potential mechanism involved in intestinal absorption and modulation of gut microbiota in Epinephelus akaara following Scy-hepc feeding. Results: The results showed that a 35 day regimen of Scy-hpec markedly promoted the growth of E. akaara compared to groups supplemented with either florfenicol, B. subtilis, or a vector. The growth enhancement is likely attributed to alterations in microbiota colonization in the foregut and midgut, characterized by an increasing abundance of potential probiotics (Rhizobiaceae and Lysobacter) and a decreased abundance of opportunistic pathogens (Psychrobacter and Brevundimonas) as determined by 16S rRNA analysis. Additionally, similar to the effect of florfenicol feeding, Scy-hepc significantly improved host survival rate by over 20% in response to a lethal dose challenge with Edwardsiella tarda. Further investigations demonstrated that Scy-hepc is absorbed by the fish foregut (20–40 min) and midgut (20–30 min) as confirmed by Western blot, ELISA, and Immunofluorescence. The absorption of Scy-hepc affected the swimming, swarming and surfing motility of Vibrio harveyi and Bacillus thuringiensis isolated from E. akaara's gut. Moreover, Scy-hepc induced the downregulation of 40 assembly genes and the upregulation expression of 5, with the most significant divergence in gene expression between opportunistic pathogens and probiotics concentrated in their motility genes (PomA/B, MotA/B). Conclusions: In summary, this study shows that feeding AMP Scy-hepc can promote growth and bolster immunity in E. akaara. These beneficial effects are likely due to the absorption of Scy-hepc in the fish's foregut and midgut, which modulates the colonization and motility of commensal bacteria, leading to favorable changes in the composition of the foregut and midgut microbiota. Therefore, a profound understanding of the mechanisms by which antimicrobial peptides affect host gut microbiota will contribute to a comprehensive assessment of their advantages and potential application prospects as substitutes for antibiotics in fish health and improving aquaculture practices. [ABSTRACT FROM AUTHOR]

Pesticides and heavy metals are considered as potent contaminants in aquatic environment. Both contaminants are sourced into the aquatic ecosystems by various types of anthropogenic as well as natural practices. Such types of aquatic contamination drastically affect the normal activity of associated living organisms particularly fish. Both the pesticides and heavy metals toxicity cause several negative effects on fish growth, physiology, immune response, reproduction, embryonic and larval development as well as different histopathology of major organs including fish gill, kidney, liver, gonads, and intestine. Besides, the consumption of contaminated fish poses a serious health concern to associated consumers. Considering these serious issues, the current review is designed to investigate the toxic effects of pesticides and heavy metals on different aspects of fishes along with their possible sources, major types, and mode of action as well as role of medicinal herbs to mitigate their toxicity. [ABSTRACT FROM AUTHOR]

The use of phytogenics that are low-cost and highly available has the potential to address some environmental, social, and economic issues in fish culture. The present study was conducted to evaluate the effects of the dietary application of pineapple (Ananas comosus) peel oil (PPO) on the growth performance of Swordtail (Xiphophorous helleri) and the antibacterial effect against pathogenic bacteria. PPO was incorporated in the diet of Swordtail (initial average weight ± SD of 0.12±0.07g and average length± SD of 1.15±0.25 cm) to analyze the effect on growth performance. Two triplicate groups (each tank stocked with 15 fish) were fed with control and experimental diet for 10 weeks. The results showed significantly enhanced growth performance of fish fed with an experimental diet. The average weight gain (282.0±35.0%), relative growth rate (2.82±0.35), specific growth rate (1.92±0.12 %day-1), and condition factor (0.42±0.02%) were all higher, and feed conversion ratio (0.0219 ±0.040) is lower in fish fed the experimental diet. The carbohydrate content (60.05±0.050 %) in the control feed was higher (p≤0.05), whereas moisture (11.35±0.11 %) and ash (13.77±0.03%) contents were higher (p≤0.05) in experimental feed. The disc-diffusion method was used to test the antibacterial activity of the crude PPO against A. hydrophila and Pseudomonas spp. The inhibition zones were 2.37±0.13 51 cm and 2.06±0.08 cm, respectively. Conclusively, the present study recommends using PPO, which has a potential antibacterial effect against bacterial pathogens, as a potential feed additive to improve the growth performance of swordtail. [ABSTRACT FROM AUTHOR]

Ensuring the appropriate dissolved oxygen concentration in the aquaculture water is crucial to the healthy growth of cultured fish. In order to meet the oxygen demand requirements for high-density aquaculture with super large water capacity of aquaculture vessel. According to the double membrane theory and Fick's law, as well as the testing standards for the oxygenation capacity of aerators, a speece cone size model was designed and its oxygen enhancement performance tests were conducted. The experiment results show that the dissolved oxygen concentration at the outlet of the speece cone reaches 40 mg/L, and the supersaturated dissolved oxygen is close to 400%, achieving ultra-high saturation dissolved oxygen. Under the conditions of an oxygen intake rate of 7.6 m³/h and an oxygen cone operating pressure of 0.07-0.25 MPa, the oxygenation capacity is not significantly affected by the operating pressure. However, the optimal intake rate range is significantly affected by the operating pressure. The higher the operating pressure, the less likely it is to form large bubbles on the water surface when the oxygen intake rate increases, thus maintaining a higher oxygen utilization rate. When the oxygen intake is greater than 6.5 m³/h and the operating pressure is between 0.07 MPa and 0.25 MPa, each aquaculture cabin is equipped with one speece cone of this structural size to meet the oxygen demand of the aquaculture cabin. The oxygenation capacity of this speece cone is significantly higher than other oxygenation devices, and its power efficiency is also higher than most oxygenation devices, which is suitable for oxygenation of aquaculture vessel. This study provides basic data for the engineering design and stable and efficient operation of the oxygen enrichment equipment of aquaculture vessel. [ABSTRACT FROM AUTHOR]

Simple Summary: This paper provides an overview of the key issues concerning the use of yeast products as an alternative protein source and feed additives to develop a more sustainable and environmentally friendly aquaculture. The use of yeast is presented in detail, with a particular focus on its use as a primary protein source and as a supplement (such as probiotics and immune stimulants). Additionally, the digestibility of yeasts and their use in live aquafeed culture are discussed in detail. The aquafeed industry increasingly relies on using sustainable and appropriate protein sources to ensure the long-term sustainability and financial viability of intensive aquaculture. Yeast has emerged as a viable substitute protein source in the aquaculture sector due to its potential as a nutritional supplement. A substantial body of evidence exists to suggest that yeast has the potential to act as an effective immune-stimulating agent for a range of aquaculture fish species. Furthermore, the incorporation of yeast supplements and feed additives has the potential to bolster disease prevention, development, and production within the aquaculture sector. Except for methionine, lysine, arginine, and phenylalanine, which are typically the limiting essential amino acids in various fish species, the various yeast species exhibit amino acid profiles that are advantageous when compared to fishmeal. The present review considers the potential nutritional suitability of several yeast species for fish, with particular attention to the various applications of yeast in aquaculture nutrition. The findings of this study indicate that the inclusion of yeast in the diet resulted in the most favorable outcomes, with improvements observed in the overall health, growth performance, and nutritional condition of the fish. Digestibility, a key factor in sustainable feed development, is discussed in special detail. Additionally, this review addresses the utilization of yeast as an immunostimulating agent for fish and its digestion in fish. Furthermore, the research emphasizes the necessity of large-scale production of yeast as a substitute for fishmeal in aquaculture. [ABSTRACT FROM AUTHOR]

The risk of predation is an important driver that tailors life histories in various ways. Using an evolutionary model based on hormonal control, we study how different predation regimes affect adaptive risk‐taking and growth in fish populations. Growth, metabolism and foraging in the modelled fish are regulated by three simplified hormone functions: growth hormone, orexin, and thyroid hormone. A dynamic state‐dependent optimization model finds optimal hormone profiles for adaptive growth strategies in juvenile fish. We consider a gradient from species where behaviour and metabolic activity have large consequences for risk (typically benthic and camouflaged species), to the opposite endpoint where behaviour may modify predation risk to a smaller degree (as in the pelagic). Along this gradient, the model predicts changes in the pace of life from slow to fast, enacted by up‐regulation of the three hormone functions which in turn increase foraging and metabolism and change the priorities of energy reserves versus growth. Under all types of predation risk investigated, growth is faster when food availability is higher. Energy reserves are maintained primarily during periods of poor food availability and are used to accelerate growth during periods when food availability is high. The thyroid hormone function is up‐regulated predominantly when food availability is high and has an important role in trade‐offs balancing energetic gain and survival. At the individual time scale, the hormone system improves organismic flexibility and robustness. Over the phylogenetic time scale, hormone system adaptations have also restricted the phenotypic plasticity of individuals. [ABSTRACT FROM AUTHOR]

Body size and growth rate can influence individual and population success by mediating fitness. Understanding the factors that influence growth can be difficult to disentangle, however, because growth can be shaped by environmental conditions recently experienced, as well as legacy effects from conditions experienced earlier in life and by parents (via parental effects).To improve understanding of growth among annual cohorts (1982–2015) of Lake Erie Walleye (Sander vitreus), a species with life‐history and growth characteristics similar to many other long‐lived, iteroparous fishes, we determined the role of the following hypothesised factors: (H1) recent environmental conditions; (H2) traits and experiences of the cohort, including growth, in the previous year; (H3) early‐life cohort density; (H4) early‐life body size; and (H5) parental composition and environment. We evaluated the relative importance of these hypothesised factors using piecewise structural equation modelling in an information‐theoretic framework.Our results indicated that cohort‐specific growth of Lake Erie Walleye was most strongly influenced by traits (growth) and experiences of the cohort during the previous year (H2) and parental composition and environment (H5). The observed negative relationship with growth during the previous year may indicate that Walleye exhibit compensatory growth. The relationships with parental sizes and environments may mean that parental contributions to offspring affects cohorts into adulthood, with serious implications for the effects of climate change. Warm winters appear to negatively influence offspring growth performance for many years.Legacy effects had a stronger influence on cohort growth than recent environmental conditions, providing new understanding of how somatic growth is regulated in Lake Erie's Walleye population. Specifically, the parental composition and environment appear important via epigenetic and/or egg‐provisioning legacies, with carryover effects modifying growth among years. Ultimately, our findings demonstrate that understanding recent growth in animal populations similar to Lake Erie Walleye may require knowledge of past conditions, including those experienced by parents. [ABSTRACT FROM AUTHOR]

The present study provides length-weight relationships (LWRs) and condition factors (Kn) estimates for ten deep-sea scorpaeniform fishes based on data consisting of new maximum size. The samples were collected from Sakthikulangara Harbour, located on the southwest coast of India, from September 2021 to December 2022. These samples were obtained as bycatch from deep-sea shrimp trawlers operating in the Arabian Sea at depths ranging from 200 to 420 m. The estimated b values ranged from 2.92 (Brachypterois serrulata) to 3.76 (Pterygotrigla arabica). The Kn ranged from 0.56 (Satyrichthys laticeps) to 1.53 (Neomerinthe erostris), with four species exhibiting Kn values higher than 1. The LWR estimates and Kn provided in this study are helpful to understand the growth characteristics of these data limited species and also to revalidate the modeled growth parameters using the Bayesian approach. [ABSTRACT FROM AUTHOR]

Curcumin, a polyphenol, targets multiple signaling molecules and shows activity at the cellular level, supporting its various health benefits. Thereafter, the present study examines the effects of different doses of dietary curcumin on growth indices, feed efficiency, serum metabolites, redox (oxidation) status, immunity, histological assessment, and antioxidant-related genes in red tilapia (Oreochromis sp, Oreochromis aureus x O. mossambicus). A total of 1200 red tilapia with an average weight of 19.1±0.03 g were distributed in 12 cement ponds (3×3.5×1m). Each treatment was assigned three pounds (n=100 replicates). For 60 days, fish were fed baseline diets containing 0, 0.4, 0.6, and 0.8 g of curcumin/kg of diet. The treated fish showed increased body weight and SGR (specific growth rate) compared to the T0 group (P<0.05). Curcumin in the diet significantly improved weight gain, percentages, and FCR (feed conversion ratio), with a dose-dependent effect (P < 0.05). Curcumin supplementation showed no influence on feed intake, fish mortality, or survival rate (P >0.05). The curcumin-treated fish groups improved tissue structure in hepatocytes, pancreatic lumens, hepatic blood sinusoids, and intestine tissue layers, particularly the mucosal layer. The T0.8 group had reduced liver enzymes (AST and ALT) and greater total protein and albumin levels (P<0.05). The T0.6 and T0.8 groups showed significantly lower MDA levels than the other groups (P < 0.05). Curcumin groups demonstrated significantly higher antioxidant indices (CAT, GPx, and SOD) compared to the basal diet (P<0.05). Curcumin administration resulted in significant improvements in IgM and lysosome levels (P<0.05). All supplemented groups had considerably (P<0.05) higher levels of SOD, CAT, and GPx mRNA than the control group. Consequently, administering 0.6–0.8 g/kg of curcumin to red tilapia (Oreochromis sp.) diets may improve the fish's growth, health, tissue composition, and antioxidant response. [ABSTRACT FROM AUTHOR]

We reviewed available data regarding the benefits of feed additives for mitigation of ammonia toxicity in fish. We first emphasized the toxic effects of ammonia and the pathways involved in ammonia metabolism in fish. Then, we focused on the roles of different dietary additives on internal ammonia detoxification and/or to counteract the negative effects of ammonia toxicity. A wide range of feed additives has been studied for their benefits in fish under ammonia exposure. Most of these studies focused on the improvement of fish health and growth performance by these additives, but neglected underlying mechanisms of these effects as well as ammonia detoxification. It is necessary to monitor internal ammonia, urea, amino acids levels, ammonia/urea excretion, and enzymes involved in ureagenesis and glutamine formation along with health-related parameters (e.g., antioxidant, immunological, and growth responses) in the future studies to fulfil the knowledge gap. Moreover, the future researches should consider the route of ammonia and supplements administration to obtain reliable and practical data. A little evidence shows that dietary nutrients may interact to change the results of dietary supplementation on ammonia toxicity remediation, which must be considered in the future studies. [ABSTRACT FROM AUTHOR]

Fish productivity has long been the subject of studies using traditional Chinese medicine (TCM). To validate TCM's effectiveness on weight gain rate (WGR) and specific growth rate (SGR), a meta-analysis study was conducted. Of the 58 studies collected from PubMed, Scopus, and Cochrane Library, 4 eligible studies were analyzed quantitatively. The extracted data were then analyzed using Review Manager (RevMan) online to determine the standard mean difference (SMD), random effect, heterogeneity, and 95% confidence intervals (95% CI). As a result, TCM administration had a favorable effect on WGR (SMD = 8.33; p = 0.0001) and SGR (SMD = 8.12; p = 0.0004). In conclusion, this meta-analysis study emphasized the efficacy of TCM to improve fish production performance. [ABSTRACT FROM AUTHOR]

In recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production. [ABSTRACT FROM AUTHOR]

We aimed to investigate the effects of Bacillus cereus YB1 on the growth, intestinal digestive enzyme activity, liver antioxidant enzyme activity, and intestinal tissue structure of juvenile black rockfish (Sebastes schlegelii). A 50‐day feeding experiment was conducted. Feeding was conducted in four diet groups: control group with no YB1 supplement in diet and three treatment groups E‐L, E‐M, and E‐H containing 105, 106, and 107 CFU/g YB1, respectively. The results revealed that the weight gain and specific growth rate of juvenile fish significantly increased, while the feed coefficient was reduced in all three diet treatment groups. This indicated that the growth of black rockfish was significantly and positively affected by YB1 feeding. Enzyme activity in the intestinal tract was not significantly affected by YB1. However, the activity of protease, amylase, and lipase increased because of YB1 treatment, except for the proteases in the E‐M diet group. Meanwhile, no significant differences were recorded in the activities of the antioxidant enzymes in liver, but the level of catalase, superoxide dismutase, and malondialdehyde activities in treatments shows a better performance compared with the control in overall perspective. Furthermore, the structural features of the intestine (i.e., number of intestinal villi, length of gut villi, and thickness of muscularis) was significantly elevated with the inclusion of B. cereus YB1 in the diet. These results reveal that dietary supplementation of B. cereus YB1 is beneficial to the boosting of enzymatic activities and structure of intestinal tissue as well as the antioxidative ability of liver tissue. Such findings suggest that fish growth would be improved under YB1 feeding conditions. [ABSTRACT FROM AUTHOR]

The Delta Select channel catfish strain (DS) was developed by selection for increased growth and carcass yield. Progeny from DS and the Delta Control (DC) strain (a randomly bred strain from the same base population as DS) were compared in three trials. Trial 1: unvaccinated ~1‐year‐old fingerlings from each strain reared communally in 0.4‐ha ponds. Trial 2: vaccinated ~ 1‐year‐old fingerlings from each strain grown in separate replicated 0.4‐ha ponds and fish in about half the ponds were given an ESC vaccine‐booster at 13 months post‐hatch. Trial 3: same procedures as Trial 2, except fish were raised in replicate 0.04‐ha ponds with no vaccine‐booster. In Trial 1 DS were larger at stocking, larger at harvest, and had higher carcass yield than DC; in Trial 2 DS were larger at harvest, had better survival and higher production/ha than DC. Vaccine‐booster had no effect on fish growth or survival. DS and DC were not different for any traits in Trial 3. Although outcome varied among trials, the overall results indicated a vaccine booster did not affect growth or survival, DS strain fingerlings grew faster than DC fingerling, and DS had higher carcass yield than DC strain fish when reared communally. [ABSTRACT FROM AUTHOR]

The efficacy of herbal supplements in mitigating heavy metals (HMs) toxicity was investigated using a widely grown fish, the Nile tilapia (Oreochromis niloticus). The experiment was conducted over two phases: during the stress phase, the experimental fishes were exposed to sub-lethal concentrations of HMs, including lead, cadmium, zinc, and copper for 15 days; following which during the feeding phase, herbal supplements were given for 70 days to ameliorate their effects. Seven groups were established: the control negative group (CON−ve), control positive group (CON+ve, without any treatment), and five groups with supplementation of 1% turmeric (TUR), cinnamon (CIN), ginger (GIN), garlic (GAR), and their mixture (MIX), respectively. A total of 315 fishes were distributed evenly in experimental tanks (15 fishes per tank, in triplicates). The results revealed that exposure to HMs led to significant (p < 0.05) alterations in all the tested parameters, i.e., liver damage and growth reduction. The herbal supplements, especially the MIX groups, ameliorated the harmful effects of HMs and restored fish growth, digestibility, carcass composition, and liver health. In conclusion, the study demonstrated that the herbal supplements were effective in reducing the HMs-linked toxicity in Nile tilapia. Future studies pertaining to the mechanisms facilitated by the various herbal bioactive substances-linked tolerance to HMs in fishes are warranted. [ABSTRACT FROM AUTHOR]

Autopolyploidization, which refers to a polyploidization via genome duplication without hybridization, promotes growth in autotetraploids, but suppresses growth in high polyploids (autohexaploids or auto-octoploids). The mechanism underlying this growth suppression (i.e. 'high-ploidy syndrome') has not been comprehensively characterized. In this study, we conducted a kinematic analysis of the root apical meristem cells in Arabidopsis thaliana autopolyploids (diploid, tetraploid, hexaploid, and octoploid) to determine the effects of the progression of genome duplication on root growth. The results of the root growth analysis showed that tetraploidization increases the cell volume, but decreases cell proliferation. However, cell proliferation and volume growth are suppressed in high polyploids. Whole-mount fluorescence in situ hybridization analysis revealed extensive chromosome polytenization in the region where cell proliferation does not usually occur in the roots of high polyploids, which is likely to be at least partly correlated with the suppression of endoreduplication. The study findings indicate that chromosome polytenization is important for the suppressed growth of high polyploids. [ABSTRACT FROM AUTHOR]

Sophora flavescens is considered to be of various medicinal and economic importance. Previous studies have shown that it has antibacterial, antioxidant, and immune‐enhancing functions. To explore the full potential of S. flavescens in fish feed development, we investigated the effects of different levels of S. flavescens added to the diet on the growth performance, haematological indices, and the intestinal bacterial community of Nile tilapia (Oreochromis niloticus). The feeding trial lasted for 56 days, and the initial weight of the fish was 40.00 ± 5.00 g. Nile tilapia were randomly divided into six groups: a control group (CN) and five S. flavescens supplementation groups (0.02%, 0.04%, 0.08%, 0.16%, and 0.3% [w/w] of S. flavescens in diet). The growth performance of fish increased first and then decreased with the increase of S. flavescens supplemental level. Compared with other experimental groups, the growth performance of fish supplemented with 0.08% S. flavescens was significantly improved (p < 0.05). Haematological indices exhibited that erythrocyte (RBC), along with leucocyte (WBC) indices, exhibited a secondary trend of increasing and then decreasing with the increase of S. flavescens, reaching the highest level at 0.08% (p < 0.05). However, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) exhibited a secondary trend of first decreasing and then increasing with the increase of S. flavescens and reached the lowest value at 0.08% (p < 0.05). Compared with the CN, alkaline phosphatase (AKP) significantly decreased and changed when the additional amount of S. flavescens was 0.04% in each treatment group (p < 0.05). In another way, the gut microbial profiles revealed that Bacteroides dominated the gut communities, and compared with the control group, two uncultured bacteria were suppressed. In addition, when the supplemental level of S. flavescens was more significant than 0.04%, the proliferation of Arcobacter cryaerophilus, Solibacillus silvestris, and Escherichia sp. in the gut of Nile tilapia was promoted. The results revealed that S. flavescens, as an additive to the Nile tilapia diet with levels ranging from 0.04% to 0.08%, can enhance the growth performance and immunity and promote the proliferation of intestinal beneficial bacteria of Nile tilapia. [ABSTRACT FROM AUTHOR]

Fish age and growth data are crucial for understanding vital species' traits and their populations. Boarfish is a pelagic species widely distributed in the Northeast Atlantic that is one of the most discarded non-commercial species on the Portuguese coast. Due to its potential valorisation as a new fishery in the Northeast Atlantic, boarfish has become object of interest in several published studies. However, since no age standard protocol has been implemented for boarfish, studies have used a variety of different otolith preparation techniques to estimate age, leading to contradicting and discrepant results. This research aims to consolidate biological insights into boarfish age and growth, lay the foundation for a standardized ageing protocol and serve as a benchmark study for the Portuguese west coast before commercial exploitation. Through the comparison of two otolith ageing methodologies, this study recommends using whole otoliths as the best method, revealing a maximum age of 15 years. The growth pattern estimated, indicated a biphasic growth pattern, with a faster initial growth rate that slows down at 2.4 years, the moment of change, when energy is allocated for sexual maturation. This finding was corroborated by a maturity ogive and analysis of fish size and otolith length relationship. [ABSTRACT FROM AUTHOR]

Diversifying aquaculture in Saudi Arabia with finfish species formerly reared in the Mediterranean Sea requires a sufficient understanding of the preferences and limits of cultured fishes under local conditions. We conducted experiments in triplicate on 41 meagre (Argyrosomus regius) juveniles of 116 g in Saudi Arabia, testing four locally available commercial feeds (42.2-48.1% crude protein, 11.8-19.9% crude fat) for 79 days to determine the growth performance of fish in local high salinity (42-45‰) and 27°C conditions. The average final weight, specific growth rate, and feed conversion ratio differed significantly among treatments. The trial achieved a feed conversion ratio of 1.09-1.52 and a specific growth rate of 1.00-1.40. The growth performance appeared to be in line with related research. We anticipate that improvement of nutritional characteristics of the feed will improve the performance of the fish. Our results indicate the feasibility of successfully rearing meagre under high salinity conditions. [ABSTRACT FROM AUTHOR]

Mobile consumers track fluctuating resources across heterogeneous landscapes to grow and survive. In river networks, the abundance and accessibility of food and the energetic consequences of foraging vary among habitats and through time, providing a shifting mosaic of growth opportunities for mobile consumers. However, a framework integrating the spatiotemporal dynamics of growth potential within riverscapes has been lacking. We present the concept of foodscapes to depict the dynamic changes in food abundance, food accessibility, and consumer physiology that contribute to spatial and temporal variation of fish growth in rivers. Drawing on case studies of salmonid fishes from Alaska to California, we illustrate how foodscapes can provide a plethora of foraging, growth, and life history opportunities that potentially contribute to population resilience. We identify knowledge gaps in understanding foodscapes and approaches for stewardship that focus on restoring diverse foraging and growth opportunities for fish and other mobile consumers in river networks. [ABSTRACT FROM AUTHOR]

The quality of the yellowfin tuna caught by small-scale fishers is heavily influenced by how the catches are handled and stored on board. One effective method that small-scale fishers can use to maintain the quality of their catch is by cooling it with ice. This helps prevent the growth of bacteria in the fish, which can cause sensory, physical, microbiological, and chemical damage. Such damage can result in poor catch quality and lower market value. Therefore, this study aimed to assess the quality of the yellowfin tuna catches by small-scale fishermen in Bone Bay, specifically at the Lonrae fish landing site. This assessment involved conducting sensory, physical, microbiological, and chemical tests on the catch. The results indicated that the catch had high quality, as evidenced by a sensory score of 8. The fish had a pH ranging from 5.7 to 5.8 and a temperature close to 0°C. The average total bacteria count was 1.1 x 104 colonies/g, and there were no traces of Salmonella or Escherichia coli (<3 MPN/g). The histamine values ranged from 6.99 to 7.31. Heavy metals, specifically mercury, lead, and cadmium, were measured at 0.05, 0.0166, and 0.0049mg/ k, respectively. [ABSTRACT FROM AUTHOR]

The present study examined the morphometric characteristics of the European pilchard, Sardina pilchardus (Walbaum, 1792) from Béni-Saf Bay (Algeria), to address the lack of data concerning the exploitation of their stocks in this area. A total of 306 specimens were examined, consisting of 49.35% males, 45.10% females, and 5.56% undetermined individuals. The overall sex ratio was 1.09, slightly favoring males (χ2 = 0,5848; P<0.05). Sixteen measurements were carried out for each specimen; the total length of the observed fish ranged from 6.4 to 22.7 cm. The length-weight relationship for S. pilchardus was determined using the regression equation Wt=aLtb. The model parameters for the relationships (LWR) indicated a positive allometric growth for both sexes (t-test, P<0.05); the coefficient of determination (R²) was 0.97 for males and 0.99 for females, indicating a strong correlation between length and weight. The equations of the length-weight relationship were Wt = 0.0057*Lt3.0981 for males and Wt = 0.0066*Lt3.0602 for females. The results of the model parameters for the relationships Y=aLtb indicate a strong correlation between all morphological measurements and total length. Regardless of sex, all parameters showed a lower growth allometry (negative allometry), with statistically significant results observed in both sexes (t-test, P<0.05). The present study demonstrated that male and female S. pilchardus from Béni-Saf Bay (Algeria) showed sexual dimorphism in favor of the females (F-test, P<0.05). Females fish have longer fin sizes than males and longer heads than males. Furthermore, females possess a longer upper jaw compared to males. [ABSTRACT FROM AUTHOR]

Nannochloropsissp is used as natural feed since it contains high good nutrition for the growth of fish larvae. However, the availability of Nannochloropsis sp. is still limited and has become a constraint in aquaculture. This study aimed to address the effect of pasta on the density of Nannochloropsis sp. cultured on the laboratory scale from pasta product of massive culture using the combination of agricultural fertilizer and water extract of Moringaoleifera leaf. Nannochloropsis sp. culture of the laboratory scale used the kw21 fertilizer. The Nannochloropsis sp. seeds were taken from Nannocloropsis sp. pasta with different concentrations, while the control Nannocloropsissp seeds used the laboratory scale without pasta. The study applied a complete randomized design with 4 treatments (NaOH pasta of 75 ppm, 100 ppm, 125 ppm, and control) and 3 replications. The control treatment (D) used the Nannochloropsis sp. of the laboratory scale without pasta. Data analysis utilized the one way-ANOVA, followed by the least significant difference test upon detecting a significant difference. Results indicated the significant effect of the NaOH pasta on Nannochloropsis sp. density. [ABSTRACT FROM AUTHOR]

Egypt, one of the world's biggest producers of cultured tilapia, is facing significant challenges in using drainage water for aquaculture due to the lack in freshwater. The current study was conducted to evaluate the effects of drainage water treatment on the growth and flesh quality of the Nile tilapia (Oreochromis niloticus), raised on five distinct fish farms in the El-Fayoum Governorate and irrigated with various drainage water sources. Fish growth characteristics, flesh quality, irrigation resources, drainage canals, and water quality of the investigated fish farms were all investigated. The Dayer El-Berka fish farm had the highest values of pH, total hardness, total alkalinity, salinity, and total ammonia, demonstrating the negative effects of the untreated drainage water on aquaculture water quality. All farms, with the exception of Dayer El-Berka and El-Bats fish farm (earthen pond), which showed a high lead content, had copper concentrations below detection limits. Wadi Al-Raian fish farm was recorded with higher cadmium concentrations. The El-Bats fish farm (concrete pond), which is watered with El-Bats drain's treated drainage water, showed the lowest levels of heavy metals. The maximum growth performance was found in the Nile tilapia raised on Wadi Al-Raian and Al-Wadi fish farms, whereas the lowest growth performance was found in Dayer El-Berka fish farms, according to productivity metrics. The current study's findings indicate that fish raised on farms that use treated drainage water for irrigation have great growth rates, superior meat quality, and safe flesh for human consumption. [ABSTRACT FROM AUTHOR]

The Nile tilapia (Oreochromis niloticus) and the African sharptooth catfish (Clarias gariepinus) are the most widely cultivated fish species in Egypt. The production cycle runs from spring to autumn, during which water temperatures are conducive to fish growth and the propagation of leeches, which transmit fish hemoflagellates (Trypanosoma spp.). A total of 710 Nile tilapia and 385 catfish were randomly collected from three different sites--two private farms and Burullus Lake--throughout the year. Fish blood samples were examined for Trypanosoma infection. Regardless of fish species or collection site, the highest infection rate of T. mukasai was observed during summer. The catfish samples showed a higher infection rate than the Nile tilapia, and fish farms had higher infection rates compared to Burullus Lake. A positive correlation was found between Trypanosoma infection and water temperature, nitrogenous compounds (unionized ammonia, nitrite, and nitrate), total bacterial count (TBC), and total coliform count (TCC). Based on these findings, Trypanosoma infection can be expected during the production cycle (spring to autumn), and it is recommended to maintain optimal water parameters to prevent conditions favorable to infectious agents. [ABSTRACT FROM AUTHOR]

In fisheries' stock assessments, the concept of "growth plasticity"—the ability of organisms to modulate their growth rates in response to environmental conditions—has gained attention in recent years. Historically, the impacts of fishing activities and environmental fluctuations were considered separately, while their combined effects have recently come into focus. This study collected 834 adult small yellow croakers (Larimichthys polyactis) from the northern Yellow Sea, the central Yellow Sea, the southern Yellow Sea, and the northern East Sea by trawling during 2020–2021. Using otolith increments as a proxy for annual somatic growth, the study reconstructed otolith chronologies during 2015–2020 for these four stocks. The results of the mixed-effects modeling suggested that temperature during spawning and previous overwintering seasons had comparable importance for the annual growth of small yellow croakers, with higher temperature promoting growth. The growth of small yellow croakers was also found to be correlated with ENSO events, with a lag of 1 to 2 years. A further investigation into combined effects revealed that higher fishing pressure might inhibit the small yellow croaker's response to favorable environmental conditions. Furthermore, considering the potential differences in growth plasticity among stocks, an analysis was conducted on the spatial variations in growth response to these factors. The analysis revealed that, compared to the stocks in the Yellow Sea, the stock from the East China Sea could exhibit higher growth, superior adaptability to temperature, and a distinctive response to fishing pressure. In conclusion, the present study, while primarily focusing on temperature, preliminarily analyzed the combined effects of fishing and environment and underscored the differences in growth plasticity between stocks in the Yellow Sea and the East China Sea. Despite the limited factors analyzed in this study, it suggests a direction for future studies, highlighting the necessity to include more environmental factors, and even population factors (e.g., the biomass of preys), for a more comprehensive understanding of the combined effects. Based on the observed differences between the two potential subpopulations, this study also provides new insights for the management of the small yellow croaker based on metapopulation dynamics. [ABSTRACT FROM AUTHOR]

Society is becoming more demanding with aquaculture's environmental footprint and animal wellbeing. In order to potentially mitigate these concerns, feed formulations could be based on eco-efficient (circular economy-driven) or organic ingredients. This study aimed to investigate the growth performance, feed utilization, and health status of juvenile Nile tilapia (Oreochromis niloticus) when fed with such feeds. The growth trial lasted for 8 weeks, and fish had an initial weight of 31.0 ± 0.5 g (mean ± SD). Fish were fed until visual satiation, in quadruplicate, with one of three isonitrogenous and isoenergetic experimental feeds: a commercial-like feed without fishmeal (PD), a diet based on ingredients compatible with organic certification (ORG), or a feed formulated using circular economy-driven subproducts and emergent ingredients (ECO). Fish fed ECO showed a tendency for decreased feed intake, while ORG fish significantly reduced their intake compared to those fed PD. Consequently, fish fed ECO (62.7 ± 5.4 g) exhibited almost half the growth than those fed PD (107.8 ± 6.1 g), while ORG fish almost did not increase their weight (32.7 ± 1.3 g). ECO and ORG diets had a lower digestibility for protein, lipid, and energy when compared to PD. Feed utilization of fish fed ECO or ORG was also lower than those fed PD. From the health-related genes analyzed, only glutathione reductase (gsr) showed statistically significant differences, being more expressed in fish-fed ECO than those fed PD. Thus, even when such novel formulations induced extreme effects on voluntary feed intake, their impact was noted only in fish growth, but not in robustness. [ABSTRACT FROM AUTHOR]

Kynurenic acid (KYNA) is a metabolite of tryptophan formed on the kynurenine pathway. Its pharmacological effects are relatively well characterized in mammals, whereas its role in fish is poorly understood. Therefore, the aim of the study was to expand the knowledge of KYNA's presence inside a fish's body and its impact on fish development and function. The study was performed on zebrafish larvae and adult rainbow trout. We provide evidence that KYNA is present in the embryo, larva and mature fish and that its distribution in organs varies considerably. A study of KYNA's effect on early larval development suggests that it can accelerate larval maturation, especially under conditions that are suboptimal for fish growth. Moreover, KYNA in concentrations over 1 mM caused morphological impairment and death of larvae. However, long-lasting exposure of larvae to subtoxic concentrations of KYNA does not affect the behavior of 5-day-old larvae kept under standard optimal conditions. We also show that ingestion of KYNA-supplemented feed can lead to KYNA accumulation, particularly in the pyloric caeca of mature trout. These results shed new light on the relevance of KYNA and provide new impulse for further research on the importance of the kynurenine pathway in fish. [ABSTRACT FROM AUTHOR]

Otoliths are frequently used as proxies to examine the impacts of climate change on fish growth in marine and freshwater ecosystems worldwide. However, the large sensitivity differences in otolith growth responses to typical changing environmental factors (i.e., temperature and CO2 concentration), coupled with unclear drivers and potential inconsistencies with fish body growth, fundamentally challenge the reliability of such otolith applications. Here, we performed a global meta‐analysis of experiments investigating the direct effects of warming (297 cases) and CO2 acidification (293 cases) on fish otolith growth and compared them with fish body growth responses. Hierarchical models were used to assess the overall effect and quantify the influence of nine explanatory factors (e.g., fish feeding habit, life history stage, habitat type, and experimental amplitude and duration). The overall effects of warming and acidification on otolith growth were positive and significant, and the effect size of warming (effect size = 0.4003, otolith size of the treatment group increased by 49.23% compared to that of the control group) was larger than that of acidification (0.0724, 7.51%). All factors examined contributed to the heterogeneity of effect sizes, with larger responses commonly observed in carnivorous fish, marine species, and young individuals. Warming amplitudes and durations and acidification amplitudes increased the effect sizes, while acidification durations decreased the effect sizes. Otolith growth responses were consistent with, but greater than, fish body growth responses under warming. In contrast, fish body growth responses were not significant under acidification (effect size = −0.0051, p =.6185) and thus cannot be estimated using otoliths. Therefore, our study highlights that the reliability of applying otoliths to examine climate change impacts is likely varied, as the sensitivity of otolith growth responses and the consistency between the growth responses of otoliths and fish bodies are context‐dependent. [ABSTRACT FROM AUTHOR]

To evaluate the effects of dietary pancreatin on growth performance, biochemical indexes, and enterohepatic structure of juvenile largemouth bass (Micropterus salmoides), specimens with of the initial body quality of (8.00±0.50) g, 630 were randomly divided into 6 groups, each group of three repetition, 35 fishes each repetition. The control group was fed with a basic diet, and 5 experimental groups were fed with pancreatin-added diet of different concentrations of pancreatin (P250, P500, P750, P1000, P1250). The experimental period was 70 days. The results show that: The growth performance of fish first increased and then decreased with the increase of pancreatin dosage. The final average weight, weight gain rate and specific growth rate of fish in P750 group were the highest, and the feed ratio was the lowest, which were significantly different from the control group. Compared with the control group, the contents of serum total protein and albumin increased, which were the highest in P500 group and P750 group, respectively. The contents of serum triglyceride and total cholesterol in the P500 and P750 groups decreased significantly. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) first decreased and then increased with the increasing amount of trypsin added. In the P750 group, the activity of AST was the lowest, and the activity of alkaline phosphatase was the highest. Compared with the control group, the P500 and P750 groups had a significant reduction in lipid vacuolization area and a significant increase in villus width; Fluff number increased significantly in the P500 group. In conclusion, dietary pancreatin could significantly improve the growth performance, biochemical indexes, liver antioxidant and enterohepatic structure of largemouth bass, and there was a dose effect of pancreatin. Based on the comprehensive analysis and the index of weight gain rate, it is suggested that the appropriate amount of pancreatin in the diet of largemouth bass is 679 mg/kg. [ABSTRACT FROM AUTHOR]

Simple Summary: Myomaker has been reported to play an important role in regulating myoblast fusion. However, the role of Myomaker gene in skeletal muscle growth in economic fish during post-hatching stage is unclear. This study showed that the growth of Chinese perch was significantly decreased when Myomaker was inhibited by Myomaker-siRNA. Furthermore, both the diameter of muscle fibers and the number of nuclei in single muscle fibers were significantly reduced in the Myomaker-siRNA group, whereas, there was no significant difference in the number of proliferating cells between the control and Myomaker-siRNA groups. Together, these findings indicate that Myomaker may promote the hypertrophy of muscle fibers and growth of fast muscle in Chinese perch by promoting myoblast fusion. The fusion of myoblasts is a crucial stage in the growth and development of skeletal muscle. Myomaker is an important myoblast fusion factor that plays a crucial role in regulating myoblast fusion. However, the function of Myomaker in economic fish during posthatching has been poorly studied. In this study, we found that the expression of Myomaker in the fast muscle of Chinese perch (Siniperca chuatsi) was higher than that in other tissues. To determine the function of Myomaker in fast muscle, Myomaker-siRNA was used to knockdown Myomaker in Chinese perch and the effect on muscle growth was determined. The results showed that the growth of Chinese perch was significantly decreased in the Myomaker-siRNA group. Furthermore, both the diameter of muscle fibers and the number of nuclei in single muscle fibers were significantly reduced in the Myomaker-siRNA group, whereas there was no significant difference in the number of BrdU-positive cells (proliferating cells) between the control and the Myomaker-siRNA groups. Together, these findings indicate that Myomaker may regulate growth of fast muscle in Chinese perch juveniles by promoting myoblast fusion rather than proliferation. [ABSTRACT FROM AUTHOR]

This study investigates the impact of different diets on fish growth and bacterial community structure present in the intestine of goldfish (Carassius auratus) and their aquaculture water under recirculating water conditions. We assumed that different types of diet would form different intestinal microbiota that may affect host growth. Using Illumina MiSeq high-throughput sequencing, we analyzed bacterial communities in goldfish fed with formulated pellet feed, Tubifex worms (Limnodrilus hoffmeisteri), and an alternating diet of both. Over a 14-day feeding trial, no significant differences in juvenile goldfish growth were observed between groups. After 7 days, diet changes significantly influenced the abundance and diversity of intestinal bacteria, with the alternating diet notably enhancing bacterial diversity in both the intestines and water. However, these differences in bacterial diversity decreased by day 14. The results indicate that diet type affects microbial community diversity in the intestines and water of goldfish, and that goldfish intestines maintain a stable core bacterial community structure. This highlights the potential for optimizing diet types to enhance microbial health and stability in aquaculture systems and, in addition, provides an important scientific basis for alternative diets in goldfish aquaculture in the industry. [ABSTRACT FROM AUTHOR]

The land-based recirculating aquaculture system (RAS) has been widely applied to fish farming as a new eco-friendly culture model. This system consists of circular culture tanks on land integrated with water treatment and recycling systems. This study investigated the growth performance of juvenile gibel carp (Carassius gibelio) cultured at high stocking density (HSD, 0.3 kg/m3) and low stocking density (LSD, 0.15 kg/m3) conditions in RAS, and evaluated the comprehensive economic profit of RAS. The body weight, body length, weight gain rate, and condition factor of gibel carp in the LSD group were significantly higher than those in the HSD group (p < 0.05). The feed conversion ratio increased significantly in the HSD group (p < 0.05). A histological analysis revealed a significantly higher density of white muscle fibers in the LSD group (p < 0.05). Relative mRNA expression levels showed that ubiquitin–proteasome system (UPS)-related genes, ub, psma2, and mafbx, were significantly expressed in the HSD group, while the s6k1 expression was elevated in the LSD group (p < 0.05). The mRNA expression levels of keap1 and hsp70 in the dorsal muscle were significantly higher in the HSD group (p < 0.05). Throughout the rearing period, the water temperature remained consistent between the two density groups. The pH value gradually decreased and the dissolved oxygen levels in the HSD group were generally lower than in the LSD group. The nitrite nitrogen (NO2−-N) content was higher in the HSD group. Compared to the LSD group, the return on investment was significantly lower in the HSD group. In conclusion, the water quality and growth rates of juvenile gibel carp were better in the LSD group. An appropriate stocking density improved the growth performance and aquaculture economic efficiency. [ABSTRACT FROM AUTHOR]

Increasing need for food resources, State of Indonesia to strive to maximize the output of food production. Not only in agriculture but also aquaculture results are also trying to be improved. This is also supported by the increase of Indonesia’s national fish consumption rate from 50.69 Kg per capita in 2018 to 55.37 Kg per capita in 2021. Recent aquaculture research only explored topics about monitoring the cultivation environment. But there have been no studies exploring how bad the impact of weather on the process of farming. Hence, this study aims to measure the influence of weather on freshwater aquaculture pond water quality and analyze its impact on fish growth namely Oreochromis Sp., using pH sensors and dissolved oxygen (DO). Then a weather simulation was carried out based on Indonesia’s tropical climate, which majorly consists of sunny and rainy weather. The experimental results indicate the instability of the pH value during the rainy period. DO values tend to decrease at the end of periods of sunny weather. Moreover, fish growth analysis showed that there was a decrease in food conversion ratio (FCR) by 0.956, specific growth rate (SGR) by 2.13% and survival rate (SR) by 5.715% during rainy weather. [ABSTRACT FROM AUTHOR]

Modifying chitosan by increasing its hydrophilic properties through sulfonation reactions will increase its solubility in water and antibacterial activity and expand the application of chitosan. This study aims to determine the antibacterial activity of sulfonated chitosan film applied as fish fillet packaging using the total plate count method. Sulfonated chitosan in this study was successfully synthesized by reacting chitosan with 1,3-propane sultone. Sulfonated chitosan products were characterized using FTIR and UV-Vis spectrophotometers, while antibacterial activity was measured using the disc diffusion method. The optimum temperature for sulfonated chitosan synthesis was 60°C (SCS60). The resulting SCS 60 was a yellowish-white solid soluble in water with a yield of 61.46% and a degree of substitution of 33%. The diameters of the SCS 60 inhibition zone against E. coli and S. aureus isolates were 7 and 10 mm, respectively. SCS60-gelatin film is elastic (elongation 272%) and more hydrophobic with a contact angle of 90.12° compared to chitosan-gelatin film (62.8°). SCC60-gelatin film was able to suppress bacterial growth in fish fillets by up to 0.3 × 104 cfu/g compared to unpackaged fish (30 × 104 cfu/g). Sulfonated chitosan has the potential to be an antibacterial food packaging material. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of polypropylene (PP) microplastics on the growth performance, hematological profile and oxidative stress responses in the liver and brain tissues of Oreochromis niloticus juvenile. The microplastic exposure was done by offering microplastic‐incorporated feed to the fish. The feed was prepared by mixing microplastics and the feed in three different ratios; Low (1.5 g/kg), Medium (3.0 g/kg), High (4.5 g/kg), and a control with no plastics in it. The trial was done for 7 weeks. A significant impact on the growth performance of the fish was observed in terms of body weight gain, specific growth rate, metabolic growth rate, protein efficiency ratio and energy retention. All the treatments had a significant difference in growth parameters compared to the control. The results of the hematological profile confirmed erythropoietic impairment in the fishes due to high microplastic exposure which led to an anemic condition in the fishes and mortality in the early juvenile stage. The antioxidant enzyme analysis also shows significant oxidative stress induced in liver and brain tissues in a dose‐dependent manner. Exposure to PP microplastics significantly affected the growth, health and metabolism of O. niloticus. Further studies on genetic and cellular levels should be done to elucidate the wide‐ranging effects of MPs on fish species. [ABSTRACT FROM AUTHOR]

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The latest advances in science, combined with the growing possibilities of modern technology, contributed to the improvement of fish feeding technology and fish farming in general. It is obvious that the expansion of the species composition of cultivated fish farming objects will continue, and the importance of feed and fish feeding technology will steadily increase. The developed recipes of starter feeds for juvenile fish and the technology of their production would make it possible to establish the production of these feeds for fish farms in Kazakhstan, as a result, the survival rate and growth rate of juvenile fish grown in industrial conditions would increase. The aim of the work was to develop recipes for starter feeds for pikeperch fry and technology for their production by extrusion, the development of these feeds to improve the efficiency of growing pikeperch in industrial conditions. According to the developed recipe, a starter feed for zander juveniles, balanced in terms of basic nutrients, was developed, a study was made of the effect of this feed on the efficiency and speed of growing zander juveniles. The dynamics of rearing juvenile pikeperch was studied when feeding the starter feed developed by the Kazakh Research Institute of Processing and Food Industry, with a feed coefficient of 1.28 and as a control foreign starter feed for trout “Aller Aqua” – 1.2. The materials of the article are of practical importance and the need for further research, they will help replenish the formulas of compound feed for the industrial cultivation of juvenile pike perch in fish farms of the Republic of Kazakhstan. [ABSTRACT FROM AUTHOR]