Fish Growth Research Articles

Effect of Scoparia dulcis Extract on Lipid Oxidation in Fish Feed, Growth Performance, and Hypoxia Tolerance in Juvenile Jian Carp (Cyprinus carpio var. Jian)

Effect of Scoparia dulcis Extract on Lipid Oxidation in Fish Feed, Growth Performance, and Hypoxia Tolerance in Juvenile Jian Carp (Cyprinus carpio var. Jian)

Effects of invasive bigheaded carp and environmental factors on larval fish growth

Effects of invasive bigheaded carp and environmental factors on larval fish growth

Effect of Dietary Supplementation on the Growth and Immunity of Fish and Shellfish

With the rapid development of aquaculture, the shortage of high-quality dietary ingredients has become a critical problem limiting the sustainable development of aquaculture [...]

The Effect of Feeding with Chironomid and Artemia on Fatty Acids and Amino Acids Profiles in Persian Sturgeon (Acipenser persicus) Larvae

This study aimed to examine the effect of various live foods on the fatty acids (FAs) and amino acids (AAs) profiles in Persian sturgeon (Acipenser persicus) larvae. One thousand and two hundred larvae were cultured in circular concrete tanks, and four treatments were administered as: (1) Artemia + Daphnia, (2) Artemia, (3) Artemia + Chironomid, and (4) Chironomid. Each treatment was considered as three replicates over an 11-day period. At the end of the experiment, treatment 1 (Artemia + Daphnia) showed the highest average weight of larvae, and the lowest weight was observed in treatment 4 (Chironomid). Survival rate ranged from 83.84% to 88.86% and no significant difference was observed among the groups (P >0.05). Among Artemia-fed larvae, the predominant FAs were docosahexaenoic acid (DHA), oleic acid (ω9), and monounsaturated fatty acids (MUFA), while saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) (ω3 + ω6) were present in a lesser proportion (P <0.05). In larvae fed with Artemia and Daphnia, the predominant proportions were observed in SFAs, eicosapentaenoic acid (EPA), ω3, DHA + EPA, and the n3/n6 ratio, all registering the highest percentages. Conversely, MUFA, ω6, and the DHA/EPA ratio displayed the lowest percentages (P <0.05). Moreover, larvae fed with Artemia exhibited higher levels of ω6, PUFA (ω3 + ω6), and DHA/EPA ratio. In contrast, larvae fed with Chironomid showed lower levels of EPA, DHA + EPA, and n3/n6 ratio (P <0.05). Among larvae fed with Chironomid, solely the DHA/EPA ratio exhibited a higher value compared to larvae fed with Artemia and Daphnia (P <0.05). The amount of leucine in fish fed Artemia + Daphnia was more than the other treatments (P <0.05). This study revealed a significant difference in amino acids composition among various live foods (P <0.05), but no significant difference in AAs was observed in the body of Persian sturgeon larvae (P >0.05). The results of this study suggest that the Persian sturgeon larvae possess the ability to maintain a balanced state of AAs. It is also evident that the FA profile of different live foods can affect the overall FA levels in the body of Persian sturgeon larvae, ultimately contributing to the enhancement of fish survival rate and growth.

The role of pantothenic acid in alleviating hypoxia-induced liver injury of sub-adult grass carp (Ctenopharyngodon idellus): Possible mechanisms and implication

In aquaculture, hypoxia poses a significant threat to fish growth and survival. Despite this, there is limited research on the impact of pantothenic acid (PA) in enhancing the anti-hypoxia stress capability of fish. The primary objective of this study was to explore the effects and potential mechanisms of PA in alleviating hypoxia-induced liver injury in sub-adult grass carp. To achieve this, six experimental diets containing varying levels of PA (0.08, 11.95, 24.95, 37.95, 50.95, and 63.95 mg/kg) were formulated and administered to grass carp (initial weight 696.22 ± 2.45 g) for 63 days. Following the dietary intervention, the fish were segregated into hypoxia and control groups and treated for 96 h. The findings revealed that optimal PA levels could enhance the growth performance of sub-adult grass carp and ameliorate the adverse impacts of hypoxia. First, optimal PA levels reduced serum levels of glutamate-oxaloacetate transaminase (GOT), glutamate-pyruvate transaminase (GPT), and lactate dehydrogenase (LDH), as well as mitigated hepatocyte vacuolization, improved liver and mitochondrial morphology, thereby alleviating hypoxia-induced liver injury. Furthermore, optimal PA levels were associated with increased contents of serum cortisol, glucose, liver glycogen, pyruvate, and the activities of Pantothenate kinase 2 (PanK2) and coenzyme A (CoA), while liver lactate content and LDH activity were reduced, indicating improvements in energy metabolism and PA utilization, potentially mediated by the down-regulation of hypoxia-inducible factor-1α (HIF-1α) mRNA level. Moreover, optimal PA levels decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels, enhanced liver antioxidant capacity, down-regulated autophagy-related gene mRNA levels, and up-regulated autophagy receptor protein 62 (p62) protein level, suggesting a reduction in oxidative damage and autophagy. Finally, a rise in levels of mitochondrial quality control-related mRNAs such as mitofusin 1/2 (MFN1/2), dynamin-related protein-1 (DRP-1), and nuclear respiratory factor 1/2 (Nrf-1/2) was observed, together with increment in the protein levels of PTEN induced putative kinase 1 (PINK1), BCL-2 interacting protein 3 (BNIP3) and FUN14 domain-containing protein 1 (FUNDC1). These alterations hinted at the role of PA in preserving mitochondrial homeostasis. In conclusion, PA exhibited a protective role against hypoxia-induced liver injury by enhancing liver energy metabolism, bolstering antioxidant defenses, suppressing autophagy, and maintaining mitochondrial homeostasis. Through an assessment of percentage weight gain (PWG) and liver ROS level, the requirements of PA for promoting growth and resilience to hypoxia-induced liver injury in sub-adult grass carp were determined to be 37.44 mg/kg and 42.57 mg/kg, respectively.

Effects of handling and surgical implant on juvenile wild trout: Physiological and behavioral impact.

Fish involved in telemetry studies are usually handled, anaesthetized, and subjected to internal tag implantation, all of which have the potential to disrupt the fish's physiology, migratory patterns, food-seeking behavior, growth, and survival. As fish tagging is a widespread standard method in aquaculture, it is crucial to gain a better understanding of the short- and long-term effects on various aspects of fish welfare. The experimental outcomes of each phase of the surgical process and how it affects the fish's ability to recover during the post-tagging period, particularly in small salmonids, are poorly understood. Thus, it is essential to measure the extent of these adverse effects to precisely extrapolate differences in surgical intervention for tagged fish compared to their unmanipulated counterparts. In our study, we explored the post-tagging impacts on wild-captured brown trout (Salmo trutta) (1+) juveniles. We examined the time effect on fish recovery after each phase of the surgical procedure, which included anaesthetized fish, followed by surgery with/without internal tagging, within the first 2 and 25 h post-surgery. Common blood parameters (glucose levels and haematocrit) and endpoints related to swimming behavior, including fish movement, direction, and social distancing aspects, were studied. The findings of the study indicated no significant changes in glucose and haematocrit levels over the observational period. Fish subjected to anesthesia and tagging procedures exhibited a significant decrease in swimming activity, recovering to baseline levels 1 h after anesthesia and 24 h after surgical (tagging) procedures in recirculating aquaculture systems. Tagged fish showed less social proximity than non-tagged fish in the first 2 h post-surgery. A significant effect size was observed between nonsurgical (anesthesia) and surgical (non-tagged/tagged) groups, highlighting a more pronounced impact associated with surgical tag interventions. Our data indicate that the magnitude of behavioral response was significantly influenced by tag weight (~1.4% body/tag weight ratio in water) among manipulated fish groups. Consequently, our study reveals that wild-captured S. trutta juveniles, tagged with commercially available low-weight acoustic tags (V6, 69 kHz), experienced negative effects on swimming performance. In surgical studies, acknowledging potential influences is crucial for accurately inferring fish physiological and behavioral status. Emphasizing fish recovery potential in both short- and long-term periods is essential for quantifying tagging effects. Future research should prioritize exploring alternative tagging technologies and refining methodologies, with a particular focus on assessing telemetry's impact on socioeconomically relevant small salmonids.

Optimum eicosapentaenoic acid + docosahexaenoic acid levels for farmed Atlantic salmon: closing the gap between science and commercial practice

The shift from fish oil to vegetable oil (VO) sources has lowered eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in salmon aquafeeds. VOs are high in omega-6 and low in omega-3 essential fatty acids like EPA and DHA, crucial for fish metabolism and immunity. Algal oil (AO), with high EPA + DHA and lower omega-6 levels supports fish health and growth, but transferring lab-controlled conditions to real-world commercial farming remains a challenge. This study explored the benefits of high dietary EPA + DHA levels through a commercial farm (CF) study in Chile and a Big Data (BD) study in Norway. The CF study, involving 625,000 Atlantic salmon, compared standard feed with AO-supplemented feed. The latter resulted in improved health responses and better fillet quality. The BD study analyzed real data from 232.6 million fish, revealing that EPA + DHA levels > 8% reduce mortality variability by 21%, improve economic feed conversion ratio by 11%, and increase the likelihood of superior harvests by 27%, demonstrating productivity benefits. Both studies emphasize the advantages of feeds with EPA + DHA levels above typical industry practices, enhancing growth, health, and nutritional quality. Importantly, the BD study complements the CF study, bridging the gap between science and aquafarms, and providing evidence that diets with EPA + DHA > 8% offer biological performance benefits for farmers, regardless of farming environments.

Probing into the impacts of endogenous and exogenous short chain fatty acids (SCFAs) in fish health and growth

Abstract Short-chain fatty acids (SCFAs) are small organic acids exist in the fish gastrointestinal tract, mainly acetate, propionate, and butyrate. These SCFAs are produced through anaerobic fermentation of dietary non-digestible carbohydrates by gut microbes. Though enough studies have been devoted to showcasing the potential of SCFAs in human nutrition, the research on their production, potential, and existence in fish has been comparatively limited until recently. This review aims to provide a comprehensive overview of the current knowledge regarding SCFAs in aquaculture. It starts with commenting on the different sources, such as substrate and microbial species that are responsible for the production of SCFAs and their transportation and ends up depicting the relationship between biofloc technology and SCFAs production. This review also discusses the factors influencing SCFA production, such as environment, diet, and feeding habits of fish. Furthermore, the biological functions of SCFAs have been highlighted, and critical findings were compiled, including immunomodulatory effects, physiological response, gut health, and immunity.

Effects of Bacillus cereusYB1 on growth, intestinal digestive enzyme activity, liver antioxidant enzyme activity, and intestinal structure of black rockfish, Sebastes schlegelii

AbstractWe 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.

Enzyme-treated microalgal co-product diets for rainbow trout aquaculture: Supporting fish growth, phosphorus digestibility, and reducing phosphorus waste emission

Aquaculture is one of the fastest-growing food sectors, producing almost 50% of fish for human consumption worldwide. However, relying on fish meal and oil for aquaculture diets is not sustainable economically or environmentally. Aquaculture feeds also contain terrestrial plant ingredients with indigestible forms of phosphorus (P), of which 70%–80% can be released into aquatic environments. This P influx contributes to eutrophication of freshwater ecosystems that can lead to anoxic conditions. This study explores a more sustainable diet for salmonids, an important and valuable seafood. Our aim was to test ingredients with highly digestible forms of P in nutritionally balanced portions to support fish growth and reduce P loading. We determined the digestibility of three feeds containing raw, extruded, and enzymatically processed microalgal co-product of Nannochloropsis oculata compared to a conventional diet. We also quantified how much P was retained and excreted. We detected highest growth in trout fed enzymatically processed co-product feed, though it was not statistically different (p = 0.846) from growth of fish fed the reference or other co-product diets. The enzyme-treated, microalgal co-product ingredient and diet had comparable values for P digestibility and solid P excretion to the reference diet, but the lowest average solid P excretion of all test diets. Trout fed the enzyme-treated diet had the highest P retention, while the reference diet had the lowest (p = 0.0429). Trout fed the enzyme-treated diet had the lowest (p = 0.0174) and negative dissolved P excretion, while those fed the reference diet had the highest. Results showed that enzyme-treated N. oculata co-product maintains digestibility, increases P retention, and reduces dissolved P excretion compared to the reference diet in rainbow trout. These findings encourage follow-up research to design and test growth performance of diets containing enzyme-treated microalgal co-product as sustainable trout aquafeed.

Non-Contact Tilapia Mass Estimation Method Based on Underwater Binocular Vision

The non-destructive measurement of fish is an important link in intelligent aquaculture, and realizing the accurate estimation of fish mass is the key to the stable operation of this link. Taking tilapia as the object, this study proposes an underwater tilapia mass estimation method, which can accurately estimate the mass of free-swimming tilapia under non-contact conditions. First, image enhancement is performed on the original image, and the depth image is obtained by correcting and stereo matching the enhanced image using binocular stereo vision technology. And the fish body is segmented by an SAM model. Then, the segmented fish body is labeled with key points, thus realizing the 3D reconstruction of tilapia. Five mass estimation models are established based on the relationship between the body length and the mass of tilapia, so as to realize the mass estimation of tilapia. The results showed that the average relative errors of the method models were 5.34%~7.25%. The coefficient of determination of the final tilapia mass estimation with manual measurement was 0.99, and the average relative error was 5.90%. The improvement over existing deep learning methods is about 1.54%. This study will provide key technical support for the non-destructive measurement of tilapia, which is of great significance to the information management of aquaculture, the assessment of fish growth condition, and baiting control.

Use of Bacillus subtilis multiplicate in the water used for biofloc formation: Growth, hemato-biochemistry, intestinal bacteria colonies, and bacterial resistance evaluations of Nile tilapia

Probiotics in the biofloc technology (BFT) system improve fish growth and immune response and promote a favorable intestinal microbiota balance. This study aimed to investigate the growth, hemato-biochemical parameters, bacterial resistance, and the number of intestinal bacteria colonies of Nile tilapia (6.23 g) reared in the BFT system with graded levels of Bacillus subtilis multiplicate (BSM) in the water. The multiplication of these microorganisms was performed in a biofactory. Fish were distributed into four different groups with graded BSM concentrations in the water of 0.00, 0.25, 0.50, and 0.75% (or 0; 750; 1500; and 2250 mL; called BSM0 (control), BSM25, BSM50, and BSM75, respectively). The experimental procedure had 45 days for growth performance evaluations and seven additional days of bacterial challenge with Aeromonas hydrophila. The experimental design was randomized into four treatments in triplicate (n = 20 fish per tank; initial stocking density of 0.50 kg m−3). Survival was 100% before and after the bacterial challenge. Increasing BSM in the BFT system had a positive linear effect on nitrite, nitrate, settled solids, hemoglobin, and hematimetric indices. BSM50 showed the highest specific growth rate, weight gain, intestinal total bacteria, and B. subtilis counts and the lowest feed conversion rate. In BSM50 and BSM75, liver glycogen levels and aspartate aminotransferase (AST) activity were higher and lower, respectively, than in the other treatments. Plasma total cholesterol, total proteins, albumin, and skin mucus total proteins and albumin were highest in BSM25. After the bacterial challenge, the number of lesions was lower in BSM75 than in the control group. In conclusion, we recommended BSM50 because it increased the growth performance and bacterial colonization in the intestine. It also decreased liver AST activity in Nile tilapia reared in the BFT system without compromising water quality and hematological and plasmatic parameters.

Potential of yeast (<i>Saccharomyces cerevisiae</i>) as feed stabilizer and growth promoter on <i>Clarias gariepinus</i> (Burchell, 1822) fingerlings

This research was carried out to examine the potential of yeast as a fish feed stabilizer and growth promoter on Clarias gariepienus with varying levels of baker’s yeast (Saccharomyces cerevisae). Clarias gariepinus fingerlings with mean weight of 2.40 grams fingerlings were obtained from Aliu Farms, Kaduna and transported to the Fishery unit located in the Zoological Garden of the school, Kaduna State University, Kaduna State Nigeria. The fish were acclimatized for two weeks in 60 Liters’ plastic tanks. Fish were stocked at 10 fingerlings per tank containing de-chlorinated tap water in triplicate. Four experimental diets with different inclusion levels of Saccharomyces cerevisiae as follows; Diet I (5%), Diet II (7.5%) Diet III (10%) and Diet IV (12.5%) and the control diet without Saccharomyces cerevisiae were formulated at 40% crude protein. Feed subjected to stability test clearly showed that stability increases with increased level of yeast with Diet IV (12.5%) having the highest at 30 minutes (76%) and 60 minutes (68%). The pelleted feeds were fed to fish at the rate of 5% of the fish biomass throughout the experimental period. The growth response was assessed in terms of daily weight gain, relative weight gain, specific growth rate, feed conversion ratio. The results showed that diet III (10%) gave the best growth performance with an average weight gain of 2.7 followed by diet IV (12.5%) of average weight gain of 2.39 g when compared to the control diet. Similarly, diet III (10%) recorded the highest survival rate of 80%. Thus, adding baker’s yeast cells into commercial fish feed at 10% improved growth and survival of Clarias gariepinus.

Recuperative Effects of Cinnamon (Cinnamomum zeylanicum) in Catla catla After Sub-Lethal Exposure to Lead.

This research was conducted to validate the beneficial effects of incorporating dietary cinnamon (Cinnamomum zeylanicum) powder (CzP) in alleviating lead (Pb) poisoning in fish. Healthy Catla catla individuals (16.36 ± 0.19g/fish) were distributed across 18 tanks in triplicate groups. The experimental groups were as follows: Control group: fish without supplementation or exposure to Pb; positive control group: fish without supplementation but exposed to 1mg/L Pb; 5g/kg CzP along with 1mg/L Pb exposure; 10g/kg CzP along with 1mg/L Pb exposure; 15g/kg CzP along with 1mg/L Pb exposure; and 20g/kg CzP along with 1mg/L Pb exposure. The trial continued for a period of 60days. Waterborne Pb had a deleterious effect on fish growth performance, body composition, blood profile, and digestive enzyme activity, along with elevated Pb accumulation in various tissues. Conversely, consumption of cinnamon effectively mitigated the toxic potential of Pb and enhanced fish longevity. Notably, 10g/kg CzP boosted growth, improved carcass quality, reversed blood indices, restored enzyme function in the gut, and mitigated Pb accumulation in tissues. In summary, the findings revealed that incorporating 10g/kg of CzP as a dietary supplement in C. catla aquaculture could effectively counteract heavy metal toxicity.

Optimisation of plasma-activated water: Plasma DBD technology and application in recirculating aquaculture system for Nile tilapia larval culture

Plasma-activated water (PAW) is a useful tool for producing pathogen-free seed fish. This study aimed to apply dielectric barrier discharge (DBD) plasma to reduce the microbial population in the water of a recirculating aquaculture system (RAS) for Nile tilapia larval culture. Initially, a PAW system prototype was developed and found to effectively reduce bacterial populations in both stagnant and circulating water. Additionally, a slight increase in water temperature was observed in the circulating water. Subsequently, the optimisation of PAW conditions in the circulating water was performed. The PAW system, with a copper anode distance of 2 cm and a 1 cm distance between the copper tip and the water surface, combined with a non-spaced cathode pad, exhibited the highest bactericidal effect. Using the optimised PAW conditions from Experiment I, Nile tilapia larval culture was established in the RAS, supplemented with a bacterial suspension (Bacillus subtilis, Streptococcus agalactiae and Aeromonas hydrophila) to assess the bactericidal effects. Three treatments were applied: 1) control (no PAW or antibiotics), 2) PAW, and 3) antibiotic treatment for Nile tilapia larvae cultured in the RAS system for 672 h. The results demonstrated that both PAW and antibiotic treatments significantly reduced the bacterial populations in the water in relation to the control (P < 0.05). Moreover, a substantial reduction in bacterial population was observed in the whole body of the fingerlings in both the PAW and antibiotic groups in relation to the control fingerlings (P < 0.05). In Experiment II, Nile tilapia larval culture in the RAS was conducted under three different conditions: 1) control (no PAW or antibiotic), 2) PAW, and 3) antibiotic treatment, to evaluate the antimicrobial effects of PAW on waterborne bacterial populations for 672 h. Similar to Experiment I, both antibiotic and plasma treatments significantly reduced the bacterial populations in the water and whole-body fingerlings in relation to the control (P < 0.05). Notably, the growth performance and whole-body composition (moisture, crude protein, crude fat, and ash) of the fingerling fish appeared comparable among the experimental groups (P > 0.05), suggesting that PAW had no detrimental effects on long-term fish culture. Therefore, PAW can be employed to effectively reduce bacterial populations in water, thus minimising bacteria-related issues in fish without adverse impacts on fish growth.

Expression of genes related to gonadal development and construction of gonadal DNA methylation maps of Trachinotus blochii under hypoxia

Chronic hypoxia can affect the growth and metabolism of fish and potentially impact gonadal development through epigenetic regulation. Trachinotus blochii (Golden pompano) is widely cultured near the coast and is sensitive to low oxygen conditions. We found that hypoxia and reoxygenation processes acted on multiple targets on the HPG axis, leading to endocrine disorders. Changes in the expression of key genes in the brain (gnrh), pituitary (fsh and lh), ovaries (cyp19a1a, foxl2, and er), and testes (dmrt1, ar, sox9, and gsdf) were associated with significant decreases in estrogen and testosterone levels. Hypoxia and reoxygenation lead to changes in DNA methylation levels in the gonads. Hypoxia upregulated the expression of dnmt1, dnmt3a, dnmt3b, tet1, and tet2 in females and dnmt3a and dnmt3b in males, while reoxygenation down-regulated the expression of dnmt1, dnmt3a, dnmt3b, tet1, and tet2 in males. Whole genome methylation sequencing showed that the number of differentially methylated regions was highest on chromosome 10 (5192) and lowest on chromosome 24 (275). Differentially methylated genes in females and males, as well as between males and females, were enriched in the oxytocin signaling pathway, fatty acid metabolism pathway, and HIF-1a pathway. In summary, hypoxia and reoxygenation can induce endocrine disorders, affect the expression of HPG axis genes, change the methylation pattern and modification pattern of gonad DNA, and then have potential effects on gonad development.

Dietary administration impact of olive pulp on growth performance, metabolic profile, immune status, and antioxidant potential of gilthead seabream (Sparus aurata L.)

Dietary administration impact of olive pulp on growth performance, metabolic profile, immune status, and antioxidant potential of gilthead seabream (Sparus aurata L.)

Intermolecular Interactions between Cysteine and Aromatic Amino Acids with a Phenyl Moiety in the DNA-Binding Domain of Heat Shock Factor 1 Regulate Thermal Stress-Induced Trimerization.

In this study, we investigated the trimerization mechanism and structure of heat shock factor 1 (HSF1) using western blotting, tryptophan (Trp) fluorescence spectroscopy, and molecular modeling. First, we examined the DNA-binding domains of human (Homo sapiens), goldfish (Carassius auratus), and walleye pollock (Gadus chalcogrammus) HSF1s by mutating key residues (36 and 103) that are thought to directly affect trimer formation. Human, goldfish, and walleye pollock HSF1s contain cysteine at residue 36 but cysteine (C), tyrosine (Y), and phenylalanine (F), respectively, at residue 103. The optimal trimerization temperatures for the wild-type HSF1s of each species were found to be 42, 37, and 20 °C, respectively. Interestingly, a mutation experiment revealed that trimerization occurred at 42 °C when residue 103 was cysteine, at 37 °C when it was tyrosine, and at 20 °C when it was phenylalanine, regardless of the species. In addition, it was confirmed that when residue 103 of the three species was mutated to alanine, trimerization did not occur. This suggests that in addition to trimerization via disulfide bond formation between the cysteine residues in human HSF1, trimerization can also occur via the formation of a different type of bond between cysteine and aromatic ring residues such as tyrosine and phenylalanine. We also confirmed that at least one cysteine is required for the trimerization of HSF1s, regardless of its position (residue 36 or 103). Additionally, it was shown that the trimer formation temperature is related to growth and survival in fish.

Association Between Muscle Growth and Transcription of a Mutant MSTN Gene in Olive Flounder (Paralichthys olivaceus).

Myostatin (MSTN, also known as growth differentiation factor-8 (GDF-8)), a member of the transforming growth factor β (TGF-β) superfamily, functions as a negative regulator of skeletal muscle development and growth. However, it is also expressed in a wide range of tissues in fish and thus may have more diverse roles in this group than in mammals. In this study, we assessed the genome-wide transcriptional expression pattern associated with the CRISPR/Cas9-mutated MSTN gene in the olive flounder (Paralichthys olivaceus) in association with changes in cell proliferation and transportation processes. There were no differences in the hepatosomatic index, and the growth of male and female fish increased in the F1 progeny of the MSTN mutants. Furthermore, the histopathological analysis showed that myostatin editing resulted in a 41.24% increase in back muscle growth and 46.92% increase in belly muscle growth in male flounder compared with normal flounder, and a 16.01% increase in back muscle growth and 14.26% increase in belly muscle growth in female flounder compared with normal flounder. This study demonstrates that editing of the myostatin gene enhances muscle growth in olive flounder, with a notably more pronounced effect observed in males. Consequently, myostatin-edited male flounder could represent a valuable asset for the flounder aquaculture industry.

A probabilistic foundation for the study of larval fish feeding, growth, and mortality rates

Survival through the larval phase is predicated on the probabilities of successful feeding, which dictates growth rates, and the probabilities of encountering predators. Here I perform a synthesis of feeding, growth, and mortality rates estimated during several studies from coastal Newfoundland, Canada, to provide a description of the probability distribution that can serve as a foundation of the expected distribution of vital rates. The standardized observations clearly follow that of skewed distributions, appropriately fit to a probability gamma distribution, with feeding demonstrating a stronger degree of skewness than either mortality or growth, possibly because each vital rate integrates prey-predator interactions over different time scales. Commonality in the underlying form of the distribution of vital rates in larval fish, along with clear functional relationships between gamma parameters, represents a probabilistic basis of expectations against which observations from prior or new studies can be contrasted. An example of the use of such expectations demonstrates that they can provide useful contextual information about the contrast among observations and our ability to identify their relationship with environmental drivers.