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This study examined the population dynamics and seasonal variation (winter-summer) in the biological characteristics of black sea bream (Acanthopagrus schlegelii) in Zhanjiang coastal waters, China. Key growth parameters were estimated using the von Bertalanffy growth model, revealing an asymptotic length (L∞) of 505.05 mm and a growth coefficient (K) of 0.26 year-¹, with an estimated longevity of 11.24 years. Mortality analysis showed a total mortality rate (Z) of 0.35 year-¹, primarily driven by natural causes (M = 0.33 year-¹) with minimal fishing impact (F = 0.02 year-¹), resulting in a low exploitation rate (E) of 0.05. Length-weight relationship (LWR) analysis indicated positive allometric growth in females and nearly isometric growth in males, with significant seasonal variations in condition factors (K). Yield Per Recruit (YPR) analysis identified a maximum sustainable exploitation rate (Emax) of 0.421, with a conservative management approach suggested at E 0.1 = 0.355. Seasonal variations in reproductive indices, with higher Gonadosomatic Index (GSI) and Hepatosomatic Index (HSI) in winter, highlight the species' reproductive cycle. The findings suggest that Acanthopagrus schlegelii is stable, with low fishing pressure. Seasonal GSI and HSI variations suggest fisheries management should time fishing to reduce impacts on reproductive success. Maintaining exploitation rates below Emax is essential for sustainable management, contributing valuable insights for fisheries conservation in coastal China. [ABSTRACT FROM AUTHOR]

The acute and chronic toxicity of lead to Anabas testudineus was determined in this study using static replacement bioassay testing. During the chronic toxicity studies, an experiment on the bioremediation of lead toxicity using Ocimum sanctum leaf powder was conducted. The 96 h LC50 values of lead for Anabas testudineus was 1.08 mg/L. Different biomarkers, such as the hepatosomatic index, gonadosomatic index, and fecundity, were significantly lower in fish subjected to 10% and 20% of the 96 h LC50 values of lead, compared to controls. The 45-day chronic exposure of fish to lead concentrations of 0.2 mg/L and above significantly lowered the number of total RBC, hemoglobin content, HCT (%), plasma protein, and cholesterol while decreasing the level of total WBC, plasma glucose, creatinine, serum AST and serum ALT. The leaf powder of Ocimum sanctum plays a significant role in ameliorating lead toxicity. [ABSTRACT FROM AUTHOR]

Macrognathus aculeatus is a local fish from the Bengawan Solo and Brantas Rivers that is threatened with extinction. Due to the lack of literacy on the biology of this fish. Biological parameters can be used to determine the condition of this fish in nature. Field observations at five stations from the two rivers were conducted to obtain samples. Biological and reproductive parameters such as weight and length, gonad maturity level (GML), Gonadosomatic Index (GSI), Hepatosomatic Index (HSI), and Condition Factor (CF) were the parameters observed in this study. All data obtained were presented as mean and standard deviation. Furthermore, analysis of variance was conducted using ANOVA (p < 0.05) to determine differences in samples from each observation station. The results showed that some biological factors had significant results (p < 0.05) on Gonadosomatic Index and Hepatosomatic Index). However, there was no significant difference (p > 0.05) in the condition factor. On the other hand, there were significant differences (p < 0.05) in body weight, total length, ovary weight, and fecundity parameters across all sampling sites. [ABSTRACT FROM AUTHOR]

Notopterus notopterus (Pallas) is a freshwater fish widely distributed on the Indian subcontinent and frequently harvested by fishermen. The present study aimed to assess the effect of photoperiod on gonad maturation in female N. notopterus to evaluate its potential as a tool to manipulate reproduction under artificial conditions. Fish were exposed to different photoperiods in five treatments, as follows: the control group (10 hr light and 14 hr dark (10L:14D), 24 hr continuous light (24L:00D), 18 hr light and 6 hr dark (18L:06D), 24 hr continuous dark (00L:24D) and 6 hr light and 18 hr dark (6L:18D). The highest mean gonadosomatic index (GSI) were observed under 24 hours of continuous dark treatment (3.07±0.2, p<0.001), suggesting an enhancement of gonadal growth with increased vitellogenic activity. On the other hand, the same parameter was minimal in the fish with a 24-hour continuous light period (0.62±0.02). The hepatosomatic index (HSI) studies indicated that there is an increase in HSI during longer periods of light exposure (1.022±0.082, p< 0.001) and a decrease during shorter periods of light exposure (0.51±0.01). The decrease of HSI in longer periods of darkness exposure may be related to the hepatic involvement in gonadal growth and maturity. Therefore, it was concluded that prolonged darkness is useful to accelerate gonadal growth and maturity in N. notopterus. [ABSTRACT FROM AUTHOR]

This study examined the population dynamics and seasonal variation (winter-summer) in the biological characteristics of black sea bream (Acanthopagrus schlegelii) in Zhanjiang coastal waters, China. Key growth parameters were estimated using the von Bertalanffy growth model, revealing an asymptotic length (L∞) of 505.05 mm and a growth coefficient (K) of 0.26 year-¹, with an estimated longevity of 11.24 years. Mortality analysis showed a total mortality rate (Z) of 0.35 year-¹, primarily driven by natural causes (M = 0.33 year-¹) with minimal fishing impact (F = 0.02 year-¹), resulting in a low exploitation rate (E) of 0.05. Length-weight relationship (LWR) analysis indicated positive allometric growth in females and nearly isometric growth in males, with significant seasonal variations in condition factors (K). Yield Per Recruit (YPR) analysis identified a maximum sustainable exploitation rate (Emax) of 0.421, with a conservative management approach suggested at E0.1 = 0.355. Seasonal variations in reproductive indices, with higher Gonadosomatic Index (GSI) and Hepatosomatic Index (HSI) in winter, highlight the species’ reproductive cycle. The findings suggest that Acanthopagrus schlegelii is stable, with low fishing pressure. Seasonal GSI and HSI variations suggest fisheries management should time fishing to reduce impacts on reproductive success. Maintaining exploitation rates below Emax is essential for sustainable management, contributing valuable insights for fisheries conservation in coastal China.

Oxynotus paradoxus, documented in the Eastern Atlantic Ocean from Senegal to Scotland at depths ranging between 92 and 1044 m, has been a subject of limited scientific attention in Portugal. Despite its presence in various Portuguese occurrence checklists, only two scientific studies have reported O. paradoxus, one off the mainland and the other off the Azores islands. In this study, conducted during fishing campaigns, four O. paradoxus specimens were caught off the southwest coast of Portugal (SW Iberian Peninsula) at depths ranging between 742 and 1238 m. Notably, an adult female achieved a new maximum depth record for this species, measuring 650 mm in total length. By examining this adult female, we provide novel insights into the ecology and biology of O. paradoxus. Morphometric measurements are compared with previous studies, revealing some intra-specific variability. The observed low hepato-, gonadosomatic, and ecophysiological indices suggest that the adult female had refrained from feeding for some time before collection. This individual-focused approach contributes significantly to the understanding of this poorly known species, especially considering its rarity. This study marks a noteworthy effort to enhance knowledge and emphasizes the importance of individual-based investigations when targeting rare species. [ABSTRACT FROM AUTHOR]

The present study investigated the best photoperiod for culturing pacu (Piaractus mesopotamicus) in recirculation aquaculture systems (RAS) based on its growth performance and hematological and oxidative stress responses. Juveniles (∼ 5 g) were subjected to five treatments (in triplicate): 24 L (light):0D (dark), 15 L: 09D, 12 L:12D, 9 L:15D, and 0 L:24D for 45 days. A total of 225 pacu individuals were randomly distributed among 15 tanks of 210 L (n = 15 per tank). Zootechnical, hematological (glucose, lactate, hematocrit, and hemoglobin), and antioxidant and oxidative stress parameters (glutathione S-transferase (GST), total antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were analyzed. The zootechnical parameters (e.g., weight gain, Fulton's condition factor, and specific growth rate) were better and worse with 9 L:15D and 24 L:0D photoperiods, respectively. The hepatosomatic index was higher and lower in the 0 L:24D and 9 L:15D photoperiods. Blood lactate levels and antioxidant and oxidative stress responses were increased in the longest photoperiods (15 L:9D and 24 L:0D). In contrast, the treatments that showed lower oxidative damage (liver, gills, brain, and muscle) were 9 L:15D and 12 L:12D. In conclusion, manipulating artificial light is one way to improve fish growth and health, where the best photoperiod for pacu farming in RAS is 9 L:15D. [ABSTRACT FROM AUTHOR]

High accumulation of lipids in hepatocytes can trigger an increase in the production of radical compounds, leading to fatty liver disease. This condition induces histological changes in the liver, especially in hepatocytes, and affects the surrounding structures. Mahogany seeds have the potential to act as a hypolipidemic agent in treating fatty liver. Mahogany seeds are known to contain phytochemical compounds which act as antioxidants. This study aimed to determine liver histopathology of rats by inducing high-fat diet after giving mahogany seeds ethanol extract which was observed through the percentage of steatosis, hepatocyte diameter, and hepatosomatic index. This study involved thirty male Sprague Dawley rats, divided into 6 groups: P0 (given commercial feed), P1 (given high-fat diet), P2 (given high-fat diet and simvastatin at a dose of 8 mg/200 g BW), P3, P4, and P5 (given high-fat diet and mahogany seeds ethanol extract at a dose of 14, 28, and 56 mg/200 g BW). The results showed that the hepatosomatic index among all treatment groups did not differ significantly; however, the percentage of steatosis and hepatocyte diameter in the groups given mahogany seeds ethanol extract significantly differed from the group given only high-fat feed. Based on these results, it can be concluded that mahogany seed ethanol extract can maintain the histological structure of the liver in male Sprague Dawley rats with fatty liver. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the effect of photoperiod on the growth and maturation of male gonads in featherback fish, Notopterus notopterus, from Farhatabad Nala of Gulbarga district, Karnataka, India. Five experimental groups were setup with five different photoperiod treatments, such as the control group (10 hr light and 14 hr dark (10L:14D), 18 hr light and 6 hr dark (18L:06D), 24 hr continuous light (24L:00D), 24 hr continuous dark (00L:24D) and 6 hr light and 18 hr dark (6L:18D). The parameters selected for the gonadal response to these light and dark regimes were the gonadosomatic index (GSI) and the hepatosomatic index (HSI). The mean GSI values were highest in the fish after 24 hours of continuous dark treatment (0.28±0.008, p < 0.001), suggesting an enhancement of gonadal growth with increased spermatogenesis. On the other hand, the same parameter was minimal in the fish with a 24-hour continuous light period (0.10 ± 0.008, p<0.001), revealing the inhibition of spermatogenesis with degenerated testicular components. The hepatosomatic index studies indicate that there is an increase in HSI during longer periods of light exposure and a decrease during shorter periods of light exposure. The decrease of HSI in longer periods of darkness exposure may be related to the hepatic involvement in gonadal growth and maturity. This study indicates that prolonged photoperiods negatively affect the reproductive success of N. notopterus. [ABSTRACT FROM AUTHOR]

Acute hepatopancreatic necrosis disease (AHPND) is the principal cause of major losses in the penaeid shrimp farm. The disease is associated with intoxication by pirAB toxins homologous with Photorhabdus insecticidal Pir toxin, a protein secreted during bacterial proliferation that affects the epithelial cells of the hepatopancreas. In this study, the progression of AHPND was evaluated by observation of the pathological changes using wet mount analysis, their effect on the hepatosomatic index (HSI) and clinical signs. The wet mount method showed progressive changes, including loss of vacuoles in the epithelial cells, massive sloughing of cells and melanised tubular necrosis, consistent with the histopathological evidence. The effect on clinical signs and HSI in diseased shrimp were significantly different (p < 0.05) concerning the time and healthy shrimp. The HSI values dropped over time, reaching 47% hepatopancreas size in diseased shrimp at 36 hpi, which coincided with the terminal stage. Criteria such as practical scoring system values ≥ 5, pale hepatopancreas without membrane, and massive sloughing of epithelial cells showed high discriminative power to identify diseased shrimp and significant association (p < 0.05) with AHPND. Tubules with deformities and loss of vacuoles in epithelial cells were also criteria with association (p < 0.001) to AHPND, but only in a high degree (G3 deformities) or absence of vacuoles in R and B cells. These criteria can be applied to facilitate AHPND presumptive diagnostic and could be used as screening tools for diagnosis or the surveillance of disease outbreaks in shrimp farms. [ABSTRACT FROM AUTHOR]

The acute and chronic toxicity of lead to Anabas testudineus was determined in this study using static replacement bioassay testing. During the chronic toxicity studies, an experiment on the bioremediation of lead toxicity using Ocimum sanctum leaf powder was conducted. The 96 h LC50 values of lead for Anabas testudineus was 1.08 mg/L. Different biomarkers, such as the hepatosomatic index, gonadosomatic index, and fecundity, were significantly lower in fish subjected to 10% and 20% of the 96 h LC50 values of lead, compared to controls. The 45-day chronic exposure of fish to lead concentrations of 0.2 mg/L and above significantly lowered the number of total RBC, hemoglobin content, HCT (%), plasma protein, and cholesterol while decreasing the level of total WBC, plasma glucose, creatinine, serum AST and serum ALT. The leaf powder of Ocimum sanctum plays a significant role in ameliorating lead toxicity.

Carcass characteristics and primal pork cuts of local pig breeds are rarely documented, therefore, the current study was conducted to establish the relation between incremental levels of Amarula oil cake (AOC), carcass traits, primal pork cuts, and relative internal organ weight of Windsnyer pigs. Twenty-five clinically healthy, growing, male Windsnyer pigs with an initial body weight of 19.92 ± 8.74 kg (mean ± standard deviation) were used. Pigs were used in their growing period when they were about 67 days old. The study lasted six weeks excluding one week of adaptation period. Pigs were allotted to pens in a completely randomized design and assigned to each of the five experimental diets, which contained 0, 50, 100, 150 and 200 g/kg DM of Amarula oil cake, respectively. Feed and water were offered ad libitum. Post slaughter, data for carcass characteristics, primal pork cuts, and relative organ weights of Windsnyer pigs were analysed using polynomial regression. There was a negative linear relationship between increasing levels of Amarula oil cake, carcass length, warm carcass weight and cold carcass weight. Stomach weight, backfat thickness, drip loss, and the hepatosomatic index increased linearly with increasing levels of Amarula oil cake. The kidneys, small intestines, and large intestine weight had a quadratic response to Amarula oil cake inclusion level. The heart, lungs, and spleen were not related to increasing levels of Amarula oil cake inclusion. Incremental levels of Amarula oil cake diets impaired carcass characteristics and the selected visceral organs, therefore Windsnyer pigs can be fed Amarula oil cake up to100 grams per kilograms dry matter. [ABSTRACT FROM AUTHOR]

Condition indices are key predictors of health and fitness in wild fish populations. Variation in body condition, therefore, can be used to identify stressful conditions that may impact endangered species, such as California’s endemic Delta Smelt (Hypomesus transpacificus McAllister, 1963). Here, we examined spatiotemporal variation in the condition indices of > 1600 Delta Smelt collected over nine years (2011–2019), a period characterized by tremendous variability in hydrodynamic and water quality conditions. The population exhibited low hepatosomatic index (HSI) and condition factor (CF) during September/October/November (fall), and both condition indices declined over the nine-year study during fall. HSI was positively correlated with indicators of pelagic productivity (e.g., Chlorophyll a, zooplankton biomass, and proximity to tidal wetlands), whereas CF was negatively correlated with temperature, peaking at a relatively cool 10–13 °C. In sum, seasonal and interannual variation in body condition corresponded most strongly with pelagic productivity and water temperature, with little correlation to freshwater outflow. Management actions that increase pelagic productivity, restore and freshen productive wetlands during late summer-fall, and reduce water temperatures overall are likely to benefit condition indices and, therefore, fitness of the Delta Smelt population.

AbstractAmphibians are believed to be sensitive to hypoxia, and in terms of this ability, they are between mammals with poor toleranсе to hypoxia and some turtles and fish with good tolerance to variable oxygen availability. However, we found that the Pallas’ spadefoot, Pelobates vespertinus (Pallas, 1771), a Eurasian anuran burrowing amphibian species, is capable of surviving in harsh hypoxia during wintering. This species can tolerate over long-term vital oxygen concentration of almost 10 times lower than the normal atmospheric air concentration (about 2%). The lethal oxygen concentration was about 1% (from 0.6 to 1.8% for different individuals), i.e. 20 times lower than the atmospheric concentration. The Pallas’ spadefoots overwinters in soils for more than half a year, having small sizes of storage organs (fat bodies and liver) and low content of lipids and glycogen in them, which are consumed at a low rate in normoxia at 3°С. Under hypoxic conditions, lipid consumption stops, and glycogen consumption increases, indicating a shift from aerobic to anaerobic metabolism. The cumulative effect of the reduced metabolic rate due to low wintering temperatures and the activation of glycolysis allows the Pallas’s spadefoot to be considered as one of the most hypoxia-resistant burrowing amphibian species studied.

For the first time, the pre-hibernation sizes of “storage” organs (liver and fat bodies), the type, concentration and total content of reserve substances (glycogen or lipids) in these organs and muscle tissue, and their change during freezing in freeze tolerant specimens of the moor frog (Rana arvalis) in the Siberian population were studied. In autumn, the relative weight of the liver (hepatosomatic index) in the studied individuals reaches 10%, which is 2–4 times higher than in most species of Eurasian ranid frogs; this determines 2–4 times greater hepatic glycogen stores. The concentration of glycogen in the muscles is about 4.4 times lower than in the liver, but the total storage of glycogen in the muscles is 43–57% of the storage in the liver. The high degree of glycogen degradation upon freezing in both tissues may indicate that it is promising to search for either high levels of glucose or other cryoprotectants than in the ranid frogs studied so far. The content of lipids in the tissues in autumn is small and not completely consumed before freezing. Probably, lipids play an insignificant role in pre-winter metabolism, and are necessary for maintaining activity after overwintering. Thus, the highest freeze tolerance of the moor frog among the Eurasian ranid frogs (−14°C to −16°C in different Siberian populations) may be due to the high relative weight of the liver, which provides a large supply of glycogen before hibernation, the participation of muscle tissue in the deposition of almost a third part of all glycogen the body, significant consumption of glycogen during freezing for cryoprotectants. The patterns of storage and consumption of pre-hibernation energy resources in frogs of the genus Rana differ greatly not only between terrestrial and aquatic hibernators but also between freeze tolerant species.

Amphibians are believed to be sensitive to hypoxia, and in terms of this ability, they are between mammals with poor toleranсе to hypoxia and some turtles and fish with good tolerance to variable oxygen availability. However, we found that the Pallas' spadefoot, Pelobates vespertinus (Pallas, 1771), a Eurasian anuran burrowing amphibian species, is capable of surviving in harsh hypoxia during wintering. This species can tolerate over long-term vital oxygen concentration of almost 10 times lower than the normal atmospheric air concentration (about 2%). The lethal oxygen concentration was about 1% (from 0.6 to 1.8% for different individuals), i.e. 20 times lower than the atmospheric concentration. The Pallas' spadefoots overwinters in soils for more than half a year, having small sizes of storage organs (fat bodies and liver) and low content of lipids and glycogen in them, which are consumed at a low rate in normoxia at 3°С. Under hypoxic conditions, lipid consumption stops, and glycogen consumption increases, indicating a shift from aerobic to anaerobic metabolism. The cumulative effect of the reduced metabolic rate due to low wintering temperatures and the activation of glycolysis allows the Pallas's spadefoot to be considered as one of the most hypoxia-resistant burrowing amphibian species studied. [ABSTRACT FROM AUTHOR]

The Peruvian moonfish (Selene peruviana) is an important fisheries resource that is landed in the main fishing harbors of Ecuador. At the local level, little information is available regarding the biology of this species, which hinders the development of management plans. The present study evaluates the reproductive characteristics of S. peruviana such as the size at sexual maturity and reproductive cycle. Specimens were obtained from artisanal and industrial catches from January 2017 to December 2018. The morphometric characteristics, sex, and maturity stage of 886 specimens were determined, and the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn) were estimated. The length-weight relationship and length at sexual maturity (L50) were evaluated with an allometry equation and multi-model analyses, respectively. The mean capture size (total length, TL) was 23.62 cm for males and 22.97 cm for females. A sex ratio (M:F) of 0.70:1.00 (χ2 = 26.28, P < 0.05) was obtained. The allometric factor of the length-weight relationship for both sexes (b) was 2.63 (t = 12.16, P < 0.05), and the coefficient of determination (r2) was 0.89, which suggests that negative allometric growth was present. The L50 (TL) was estimated to be 22.61, 23.86, and 23.27 cm for males, females, and sexes combined, respectively. The monthly GSI, HSI, and Kn values were significantly different (K-W, P < 0.05) among study months. The maximum GSI values were observed in February and March, which constituted the period of highest reproductive activity. The HSI and Kn values exhibited similar trends. The size at sexual maturity was similar to the average catch size, which could indicate that S. peruviana is currently at the limit of its optimal catch size.

This study aims to determine the vitelogenesis activity by FSH hormone induction in the early stage of gonadal maturation. The treatament is a differences FSH dose with indicators of vitelogenesis activity were estradiol-17β levels in the blood, Hepatosomatic index (HSI) and Gonadosomatic Index (GSI). The study used a treatment A : Dose FSH at 1.0 ml/kg; B: Dose FSH at 1.25 ml/kg; C : Dose FSH at 1.5 ml/kg; control: nothing induction. The results showed that there was an effect of FSH dose on the estradiol 17β levels, HSI and GSI, there ongoing vitelogenesis activity. The trend of the GSI and HSI has a close correlation to levels of estradiol 17β, with the best dose of the hormone is 1.25 ml/kg resulting levels of esradiol 17β amounting to 63.35 pg / ml and the GSI and HSI are 3.45% and 1.48%. Furthermore, the best treatment successively resulted in increased levels of estradiol 17β, HSI and GSI in treatment C of 41.77 pg/ml, 1.48%, 3.24%; A : 28.01 pg / ml, 1.14 %, 3.42%;. FSH is suitable for reproductive domestication in Channa marulioides. [ABSTRACT FROM AUTHOR]

The aims of this study were to compare male and female sea trout (Salmo trutta) with respect to their hypo-osmoregulatory ability over a simulated migration to seawater and their clinical and physiological response to salmon louse (Lepeophtheirus salmonis) infection in seawater and over a simulated pre-mature return to freshwater. For this purpose, 2-year-old hatchery-reared male and female brown trout (F1 offspring of wild caught anadromous fish) were infected with salmon lice and measured for changes in plasma ions, glucose, lactate and osmolality and relative heart, liver and gonad sizes during a simulated seawater migration and thereafter a premature return to freshwater after 4 weeks in seawater (pre-adult louse). Un-infected trout served as control. Male trout used longer time to develop full hypo-osmoregulatory ability in seawater and showed a stronger response in plasma glucose and lactate following simulated premature return to freshwater, compared to female trout. Response to salmon louse was stronger in female trout, shown by stronger osmotic stress by chalimus (plasma Cl−) and pre-adult louse (plasma osmolality) and elevated relative liver size (hepatosomatic index) by pre-adult louse in female compared to male trout. Moreover, high plasma cortisol in infected female and low plasma cortisol in infected male trout produced a significant treatment–sex interaction on plasma cortisol. Lice infection intensity was initially higher in male (0.18 lice g−1) compared to female trout (0.11 lice g−1) at the chalimus stage, but equal between sexes at the pre-adult stage (male 0.15 and female 0.17 lice g−1). This study showed that female trout were better adapted for changes in water salinity, while male trout were more robust against salmon louse infection. These results suggests that the elevated salmon louse infection pressure generated by salmon farming have strong and unexplored negative effects on wild sea trout populations. Further research on this topic is vital for the conservation of wild sea trout populations. [ABSTRACT FROM AUTHOR]

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Simple Summary: Ciguatoxins (CTXs) are potent neurological marine toxins able to cause ciguatera poisoning (CP) in humans via the food web. Although considered one of the most important food-borne diseases in the world, little is known about how CTXs are metabolized in fish, and the possible alteration of hepatic metabolomic linked to these toxins. To clarify this aspect, goldfish (Carassius auratus) were fed with C-CTX1 enriched flesh, and their livers were analyzed by nuclear magnetic resonance (NMR). Altered concentrations of glucose, glycogen, taurine, alanine, and lactate were observed. Furthermore, an increase in liver size was noted in animals fed a toxic diet. In addition, increased ammonia concentrations in the aquarium with toxic feed were detected. These results suggest that C-CTX1 ingestion leads to changes in liver metabolomic, which are related to the glucose-alanine cycle. This is the first evidence of CTXs-mediated alterations in liver metabolomic, and a step to further elucidate the metabolism of these toxins within fish. Ciguatera poisoning (CP) is a foodborne disease known for centuries; however, little research has been conducted on the effects of ciguatoxins (CTXs) on fish metabolism. The main objective of this study was to assess different hepatic compounds observed in goldfish (Carassius auratus) fed C-CTX1 using nuclear magnetic resonance (NMR)-based metabolomics. Thirteen goldfish were treated with C-CTX1-enriched flesh and sampled on days 1, 8, 15, 29, 36, and 43. On day 43, two individuals, referred to as 'Detox', were isolated until days 102 and 121 to evaluate the possible recovery after returning to a commercial feed. At each sampling, hepatic tissue was weighed to calculate the hepatosomatic index (HSI) and analyzed for the metabolomics study; animals fed toxic flesh showed a higher HSI, even greater in the 'Detox' individuals. Furthermore, altered concentrations of alanine, lactate, taurine, glucose, and glycogen were observed in animals with the toxic diet. These disturbances could be related to an increase in ammonium ion (NH4+) production. An increase in ammonia (NH3) concentration in water was observed in the aquarium where the fish ingested toxic meat compared to the non-toxic aquarium. All these changes may be rationalized by the relationship between CTXs and the glucose–alanine cycle. [ABSTRACT FROM AUTHOR]

For the first time, the pre-hibernation sizes of "storage" organs (liver and fat bodies), the type, concentration and total content of reserve substances (glycogen or lipids) in these organs and muscle tissue, and their change during freezing in freeze tolerant specimens of the moor frog (Rana arvalis) in the Siberian population were studied. In autumn, the relative weight of the liver (hepatosomatic index) in the studied individuals reaches 10%, which is 2–4 times higher than in most species of Eurasian ranid frogs; this determines 2–4 times greater hepatic glycogen stores. The concentration of glycogen in the muscles is about 4.4 times lower than in the liver, but the total storage of glycogen in the muscles is 43–57% of the storage in the liver. The high degree of glycogen degradation upon freezing in both tissues may indicate that it is promising to search for either high levels of glucose or other cryoprotectants than in the ranid frogs studied so far. The content of lipids in the tissues in autumn is small and not completely consumed before freezing. Probably, lipids play an insignificant role in pre-winter metabolism, and are necessary for maintaining activity after overwintering. Thus, the highest freeze tolerance of the moor frog among the Eurasian ranid frogs (−14°C to −16°C in different Siberian populations) may be due to the high relative weight of the liver, which provides a large supply of glycogen before hibernation, the participation of muscle tissue in the deposition of almost a third part of all glycogen the body, significant consumption of glycogen during freezing for cryoprotectants. The patterns of storage and consumption of pre-hibernation energy resources in frogs of the genus Rana differ greatly not only between terrestrial and aquatic hibernators but also between freeze tolerant species. [ABSTRACT FROM AUTHOR]

In Ecuador, Peprilus medius is an important fishery resource whose destination is for local consumption and export. There are few local studies on its reproductive biology, and its capture is not regulated. Therefore, this study evaluates the most relevant aspects of its reproductive activity. Samples were obtained monthly from January to December 2017 from the capture of the purse seine fleet and the artisanal gillnet fleet landing near Manta. The morphometric analysis included the length-weight relationship, estimated using the allometry equation. The size at sexual maturity is based on the L50 criterion; the reproductive cycle was determined according to the monthly analyses of the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn). A total of 334 specimens were analyzed, with average sizes of 22.0, 21.87, and 21.91 cm of total length (TL), for males, females, and combined sexes, respectively. Sex ratio was 1.17M: 1F (P > 0.05), while the length-weight relationship showed negative allometric growth for both males and females (b = 2.58; CI95% 2.48-2.72). Size at sexual maturity L50 was estimated at 21.84 and 21.23 cm TL for males and females, respectively. The GSI and HSI values and Kn showed significant differences among months (P < 0.05), with a marked seasonality during the single reproductive period. Mean size at first capture of 21 cm TL is recommended. [ABSTRACT FROM AUTHOR]

The current investigation was carried out with an aim to evaluate disparity in haematological and serum biochemical parameters of healthy male and female Schizothorax labiatus with respect to its four reproductive phases, i.e. preparatory (autumn), pre-spawning (winter), spawning (spring) and spent (summer). The study indicated that significant (p < 0.05) alterations were seen in gonadosomatic index (GSI) of S. labiatus with maximum value for both sexes noted in spring while minimum value in autumn. Contrary to this, the highest value of hepatosomatic index (HSI) for both sexes was noted in the autumn season and the lowest value in spring. The haemoglobin (Hb) content, red blood corpuscle (RBC) and white blood corpuscle (WBC) counts and haematocrit amount of S. labiatus also revealed significant (p < 0.05) variations with peak values noted in summer while least values were recorded during winter. It was also observed that male fishes comprised significantly (p < 0.05) maximum level of all these parameters amongst all seasons of the year, except WBC count. Erythrocyte indices specifically mean corpuscular haemoglobin (MCH), MCH concentration (MCHC) and mean corpuscular volume (MCV) exhibited insignificant (p > 0.05) alterations between the sexes. The lowest levels (p < 0.05) of serum glucose, cholesterol and urea were recorded in the pre-spawning period, i.e. winter, while as the highest values (p < 0.05) were seen in the summer because of the cessation of reproductive activities and greater availability of food. Similar trend was also noted in the amount of total protein, albumin and globulin of the fish, although insignificant (p > 0.05) variation was observed between sexes. [ABSTRACT FROM AUTHOR]

Therefore, salinity is one of the most critical factors determining snook distribution and potential for cultivation because the broodstock reproduces in oceanic waters and the juveniles migrate to brackish and low salinity waters to continue their growth (Gracia-López et al., 2006). In summary, it appears that black snook presents higher growth performance at intermediate salinity (13 g-L SP -1 sp ) when compared with ambient seawater and would not compromise fish welfare. Growth, survival and morphological condition of juvenile of black snook (Centropomus nigrescens, Günther 1864) reared at different salinities in a pilot-scale recirculating aquaculture system Keywords: growth rate; hepatosomatic index; viscerosomatic index; black snook EN growth rate hepatosomatic index viscerosomatic index black snook 4882 4886 5 08/10/22 20220901 NES 220901 The black snook or robalo prieto (Alvarez-Lajonchère & Tsuzuki, 2008), I Centropomus nigrescens i (Günther, 1864), has been identified as a promising high-value commercial candidate for aquaculture diversification (Resley et al., 2014; Yanes-Roca et al., 2018). [Extracted from the article]

Abstract: Mercury is a dangerous contaminant for aquatic organisms. Seurukan fish (Osteochilus vittatus) is a type of fish in the Krueng Sabee river that is vulnerable to mercury exposure. The study's purposes were to investigate the effect of mercury on the biometric conditions of Seurukan Fish in the Krueng Sabee River, Aceh Jaya Regency. A total of 90 Seurukan fish consisting of 50 males and 40 females were collected from 3 research stations. The research stations represent the upstream area (Station 1), median river bodies (Station 2), and the downstream area (Station 3). Fish samples were taken from July to August 2019. The main parameters observed included class interval, sex ratio, length-weight relationship, condition factors, mercury concentration in sediment and liver, and hepatosomatic index. The results showed that the mercury content in the sediments of the Krung Sabee River was increased both spatially and temporally. Station 1, located in the upstream area, has the highest mercury content in the sediment was 6.278 ± 0.987 mg/kg. Mercury content in liver of Seurukan Fish ranged from 0.182 ± 0.100 mg/kg to 0.198±0.152 mg/kg. Mercury contamination in the Krueng Sabee river caused a decrease in biometric conditions of Seurukan Fish. Seurukan Fish exposed to mercury tended to have smaller size, an unbalanced sex ratio, low hepatosomatic index value, and negative allometric growth pattern. Abstrak: Merkuri merupakan salah satu jenis kontaminan berbahaya bagi organisme akuatik. Ikan seurukan (Osteochilus vittatus) merupakan salah satu jenis ikan di sungai Krueng Sabee yang rentan terpapar merkuri. Penelitian ini bertujuan untuk mengkaji pengaruh merkuri terhadap kondisi biometrik ikan seurukan di sungai Krueng Sabee, Kabupaten Aceh Jaya. Sebanyak 90 ekor ikan Seurukan yang terdiri dari 50 ekor jantan dan 40 ekor betina dikoleksi dari 3 stasiun penelitian. Stasiun penelitian mewakili wilayah hulu (stasiun 1), badan sungai (stasiun 2) dan wilayah hilir (stasiun 3). Pengambilan sampel ikan dilakukan pada bulan Juli hingga Agustus 2019. Parameter utama yang diamati meliputi selang kelas, nisbah kelamin dan hubungan panjang bobot ikan, faktor kondisi, konsentrasi merkuri pada sedimen dan hati serta indeks hepatosomatik. Hasil penelitian menunjukkan bahwa kandungan merkuri di sedimen Sungai Krung Sabee mengalami peningkatan baik secara spasial dan temporal. Stasiun 1 yang terletak di wilayah hulu memiliki kandungan merkuri dalam sedimen paling tinggi yaitu sebesar 6,278 ± 0,987 mg/kg. Kandungan merkuri pada hati ikan seurukan di Sungai Krueng Sabee berkisar antara 0,182 ± 0,100 mg/kg hingga 0,198 ± 0,152 mg/kg. Kontaminasi merkuri pada sungai Krueng Sabee menyebabkan dampak negatif terhadap kondisi biometrik ikan seurukan. Ikan seurukan yang terpapar merkuri cenderung memiliki ukuran panjang dan bobot yang lebih kecil, nisbah kelamin yang tidak seimbang, dan nilai indeks hepatosomatik yang rendah serta pola pertumbuhan alometrik negatif.

The purpose of this study was to analyse the influence of water salinity on fry development of hybrid Malaysian mahseer under controlled conditions. The physical changes and the tolerance limits in stress condition due to salinity exposure were determined in a recent study. The experiment was conducted in the wet laboratory, Department of Aquaculture. Ovatide hormone (0.4 ml/kg) was used to induce ovulation of female Barbonymus gonionotus, while the sperms were collected from the male mahseer. The recent study was done to investigate the effects of salinity on hybrid fish in terms of survival, growth, histological changes, blood content and hepatosomatic index (HSI) under laboratory conditions. This study exposed the fish to different concentrations of salinity (0, 3, 6 and 9 ppt) for 3 months. All treatments were in triplicate, labelled and arranged in a randomized design. Fry were fed until satiation twice a day and 30% of water was changed daily. The highest growth rate and survival rate (84%±7.78%) of fry were obtained in 3 ppt water salinity, while the lowest growth performance and survival rate (67%±13.45%) occurred at 0 ppt. The highest body gains and lengths of fry were observed in 9 ppt water salinity. However, significant histological alterations were observed in 9 ppt water salinity which caused major anomalies such as structural alterations in portal vein, vacuolation, necrotic hepatocytes, aggregation of blood cells and melanomacrophages. New strains of hybrid Malaysian mahseer were successfully bred. Optimal condition for fry Malaysian mahseer hybrid was 3 ppt water salinity. The results show that excessive salinity in the aquatic conditions affected negatively the health of the hybrid fish.

Mortality of fish has long been recognized as the evident indication of pollution, nevertheless, the increasing low-level pollution may lead to a long-term decline and eventual extinction of fish stocks. This study investigates the impact of a point source pollution (El-Sail Drain) on the biological parameters of redbelly tilapia (Coptodon zillii) in the River Nile at Aswan, Egypt. The present results showed a significant variation of the physicochemical parameters and heavy metals of the River Nile waters in the vicinity of El-Sail Drain. On the other hand, metal concentrations in the gonads of C. zillii from the downstream of the pollution source were significantly higher than that of the unimpacted upstream area. The sex ratios of C. zillii varied in the two studied areas, where it was 1:1.38 in the unimpacted area and was 1:0.9 in the impacted area. While the GSI values of the impacted area were decreased significantly (p

The climbing perch Anabas testudineus, the most demanded indigenous fish species of India, were used for the evaluation of reproductive strategy and gonadal development at first maturation under the controlled laboratory condition. In both sexes, four distinct gonadal developmental stages namely preparatory, pre-spawning, spawning, and post-spawning were identified based on the gonadosomatic index (GSI), hepatosomatic index (HSI), gonadal morphology, and the levels of serum sex hormones. The spawning stage was identified from July and August and the fecundity ranged from 6500–11000 eggs. The GSI exhibited a significant increase from preparatory to pre-spawning and spawning stages, and maintained high until August. The HSI was maintained the same during preparatory, pre-spawning, and spawning stages while increased in post-spawning stage in both sexes. Serum estrogen and testosterone levels increased significantly during pre-spawning, and spawning stages in both sexes. Fecundity showed a positive correlation with the length, weight, and ovary weight. Histological sections showed that male A. testudineus were group-synchronous spawners. Both sexes showed discrete reproductive cycles characterized by distinct changes in gonadal size, sex hormones and gonadal indices. This study will bridge the gap of insufficient knowledge to support the best practices suitable for the A. testudineus culture and survival under captivity.

The purpose of this study was to evaluate the effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia (Oreochromis niloticus). The experimental design was completely randomized in a 4 × 2 factorial scheme with four replicates. The treatments were established by the combination of salinities of 0, 10, 20, and 30 g L-1 with an animal-plant combination diet (AP) or plant-based diet (P). The replicates were 60 L tanks with 12 fish per tank. Diets were provided for 32 days, and the fish were fed three times a day (8, 12, and 17 h) until apparent satiety. Daily feed intake (DFI) was measured, body weight (BW) was recorded at the beginning and end of the trial, and total length (TL) and standard length (SL) were measured at the end of the trial. Average daily gain (ADG), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate were calculated. After the biometric measurements were made at the end of the trial, blood samples were collected to determine the plasma concentrations of total protein (TP), glucose, cholesterol, and triglycerides (TG). The fish were euthanized, and the hepatopancreas was collected and weighed; thereafter, the hepatosomatic index (HSI) was calculated. An interaction was detected between salinity and diet type for final BW, ADG, TL, and SL. These traits were not influenced by salinity when it was associated with the AP diet, but reduced linearly with salinity in the P diet. DFI and survival rate were independently affected by salinity: DFI reduced linearly with salinity levels and survival rate was higher at a salinity of 10 g L-1. HSI increased linearly with salinity levels and was lower in the P diet than in the AP diet. Salinity had a quadratic effect on plasma TP, and the maximum value for this metabolite (2.96 g dL-1) is attained at a salinity of 10.26 g L-1. There was an independent effect of diet on the plasma concentrations of cholesterol and TG, which were lower in the P diet than in the AP diet. The salinity of 10 g L-1 associated with diet composed of animal and plant ingredients led to a better performance, higher survival rate, and less stressful environmental conditions for juvenile Nile tilapia.

This study aimed to assess the effects of 17a-methyltestosterone (MT) on the growth and reproductive performance of male Asian catfish (Clarias macrocephalus). A total of 36 immature male Asian catfish (ABW = 125.97 g) were randomly distributed into 12 circular tanks, and fed with either the control diet (with no MT) or diets containing MT at 60 mg·kg-1, 90 mg·kg-1, or 120 mg·kg-1 for 45 days. Results showed that weight gain (WG), specific growth rate (SGR) and feed intake (FI) were significantly higher in the male catfish fed with diets containing 60 and 90 mg·kg-1 MT than in those fed with the control diet. Also, the diet attractability test revealed that the 60 and 90 mg·kg-1 MT groups significantly attracted more catfish than did the control diet; however, increasing MT to 120 mg·kg-1 reduced its attractability to the immature male catfish. MT-treated male catfish exhibited significantly heavier and significantly longer testes than male catfish fed the control diet at the termination of the feeding trial. These male catfish also exhibited significantly higher gonadosomatic indices (GSI) than catfish in the control group. Following induced spawning of nontreated female catfish and artificial fertilization of its eggs using testis preparation from the experimental male catfish at the termination of the feeding trial, results showed that testis preparations from all MT-treated males resulted in significantly higher fertilization (FR) and hatching rates (HR) of the eggs. In conclusion, incorporating MT to the diet improved both the growth and reproductive performance of the male Clarias macrocephalus. Precisely, dosages of optimal dietary MT using a quadratic model for maximal SGR, GSI, FR, and HR values were estimated to be 58.3, 75.0, 90.6, and 78.2 mg·kg-1, respectively. [ABSTRACT FROM AUTHOR]

The length-weight relationship (LWR) plays an important role in fishery management as it can be used to estimate the average weight of a specific length group. The results of the current study revealed that the mean values of regression coefficient b for both sexes of Schizothorax labiatus (McClelland) in the Jhelum River indicated positive allometric growth, while in the Sindh River, the b value for males indicated positive allometric growth and for females negative allometric growth. The value of coefficient of determination r2 for both sexes of S. labiatus was equal to or greater than 0.90 in both water bodies, except for females in the Sindh River. Higher significant (P < 0.05) average values of Fulton's condition factor (K) and the hepatosomatic index (HSI) for both sexes of S. labiatus were noted in the Jhelum River than in the Sindh River. In contrast, higher significant (P < 0.05) values of the gonadosomatic index (GSI) were recorded in the Sindh River. The data generated during the current study provide basic information for researchers and fish biologists for the conservation and sustainable management of this commercially important food fish species in the Kashmir Valley. [ABSTRACT FROM AUTHOR]

We exposed adult individuals of the sentinel mangrove crab Minuca rapax to waterborne microplastics (MP; 53–63 μm polyethylene spheres) in a long-term experiment (56 days). Weassessed 1) MP effects on growth, survival, and food intake. and 2) the MP tissue acumulation and its reduction of body burden through feces and molting. MP exposure did not affect growth and survival. The hepatopancreas accumulated more MP than the gills and muscle. Most of the ingested MP particles were released in the feces and molts, indicating a rapid passage through the digestive tract. MP impaired food intake of M. rapax, with unknown consequences to the local populations. These results provide insights on MP translocation mechanisms, its elimination and toxicity associated with MP. [Display omitted] • Long-term MP exposure did not affect growth and survival of M. rapax. • High rates of MP were released by the feces and molts. • MP accumulation was higher in the hepatopancreas than in the gills or muscles. • Food intake was lower in individuals exposed to MP than the control treatment. [ABSTRACT FROM AUTHOR]

The length-weight relationship, condition factor, fecundity, gonadosomatic and hepatosomatic indices of Parachanna obscura from the Anambra River were determined between December 2015 and June 2016. Eighty-three live samples of P. obscura were obtained from fishermen. Descriptive statistics, correlation and regression analysis were used to analyze the obtained data. The length-weight relationship had R values of 0.933, 0.843 and 0.896 for male, female and combined sexes, respectively. The b value of 3.133 for male and 2.674 for female were not significantly different (P>0.05). Mean condition factors of 0.89±0.33 and 0.80±0.21 were obtained for female and male, respectively. The largest number of eggs (10,965) was found in a female with the body weight of 154 g, gonad weight of 9.1 g and egg size of 1.3 mm, while the least fecund female with 1820 eggs weighed (94 g) and had a gonad weight 2.1 g with egg size of 1.0 mm. The hepatosomatic indices ranged between 0.55±0.20 and 0.64±0.29 in both male and female, respectively, while female gonadosomatic index average was 2.05±1.44. There was a positive correlation between fecundity and gonad weight.

Curcumin exhibited numerous key activities including antioxidant, anti-inflammatory, and immunostimulatory effects in fish. This study evaluated the protective effects of curcumin (CUR) against lead (Pb)-induced toxicities in fish. Healthy Cyprinus carpio L. individuals were segregated into control, Pb only, Pb+CUR, and CUR only groups. Pb groups were exposed to 1 mg L −1 of Pb, and CUR groups were fed a basal diet supplemented with 15 g kg−1 of CUR. After eight weeks, growth performance, Pb accumulation in tissues, various haemato-biochemical parameters, immune responses, and cytokine gene expression were measured. Dietary CUR effectively decreased Pb accumulation in tissues and increased the survival of Pb-exposed fish. Co-treatment with Pb and CUR reversed alterations in haemato-biochemical parameters, ameliorated Pb-induced oxidative stress, enhanced immune responses, and restored intestinal enzymatic activities. Dietary CUR reversed changes in intestinal microbiota in Pb-exposed fish. Pb-induced upregulation of NF-κBp65 and HSP70 was inhibited by dietary CUR. CUR supplementation upregulated the mRNA levels of SOD, Nrf2, IL-10, and CYP450 1A and attenuated Pb-induced degradation of I κB-α mRNA levels. Overall, CUR antagonizes Pb-induced negative impacts in fish. Thus, dietary CUR had several beneficial effects on immune responses, decreased Pb accumulation in tissues, and reversed Pb-induced oxidative stress in fish. Therefore, CUR plays a protective role in Pb-induced immune toxicity in fish, and, as such, may be suitable as an aqua feed additive for use in carp aquaculture.

The purpose of this study was to analyse the influence of water salinity on fry development of hybrid Malaysian mahseer under controlled conditions. The physical changes and the tolerance limits in stress condition due to salinity exposure were determined in a recent study. The experiment was conducted in the wet laboratory, Department of Aquaculture. Ovatide hormone (0.4 ml/kg) was used to induce ovulation of female Barbonymus gonionotus, while the sperms were collected from the male mahseer. The recent study was done to investigate the effects of salinity on hybrid fish in terms of survival, growth, histological changes, blood content and hepatosomatic index (HSI) under laboratory conditions. This study exposed the fish to different concentrations of salinity (0, 3, 6 and 9 ppt) for 3 months. All treatments were in triplicate, labelled and arranged in a randomized design. Fry were fed until satiation twice a day and 30% of water was changed daily. The highest growth rate and survival rate (84%±7.78%) of fry were obtained in 3 ppt water salinity, while the lowest growth performance and survival rate (67%±13.45%) occurred at 0 ppt. The highest body gains and lengths of fry were observed in 9 ppt water salinity. However, significant histological alterations were observed in 9 ppt water salinity which caused major anomalies such as structural alterations in portal vein, vacuolation, necrotic hepatocytes, aggregation of blood cells and melanomacrophages. New strains of hybrid Malaysian mahseer were successfully bred. Optimal condition for fry Malaysian mahseer hybrid was 3 ppt water salinity. The results show that excessive salinity in the aquatic conditions affected negatively the health of the hybrid fish. [ABSTRACT FROM AUTHOR]

The increasing demand for herbicides in agricultural fields affected aquatic environments as they entered into water bodies by agricultural runoff. Glyphosate (GLY), an organophosphate herbicide, is widely used in India for weed control. This study aimed to evaluate the toxic effects of GLY on climbing perch Anabas testudineus by studying its effects on the gonadosomatic index (GSI), hepatosomatic index (HSI), gonad and liver histology, spawning performance, and haematological parameters (RBC, WBC, haemoglobin). In this study, Anabas testudineus were exposed to three sub‐lethal concentrations of GLY such as T1: 2.6 ppm (1/30th of 48h LC50), T2: 3.9 ppm (1/20th of 48h LC50) and T3: 7.8 ppm (1/10th of 48 hr LC50) for 45 days with 12 fish in each tank. Results indicated a significant decrease in GSI, HSI, structural alterations in testis, and ovary on 30th and 45th days of exposure. Vacuolation in tissue, dilution of sinusoid, altered tissue architecture in the liver, reduction in spawning performances (fertilization and hatching rate), increase in WBC count, decrease in RBC number and haemoglobin content were observed in all treatment groups on the 45th day exposure. Thus, the outcome of the present study revealed that the herbicide could deleteriously impair reproductive fitness, alter the liver structure, and haematological parameter of A. testudineus with a possible reduction in growth and population size. [ABSTRACT FROM AUTHOR]

A balanced combination of protein sources to partially replace fishmeal in the diets of cultured carnivorous fish can promote optimal fish health and production performance. In the present study, the growth, body condition and gut microbiota of juvenile dusky kob Argyrosomus japonicus fed fishmeal-substituted diets comprising different blends of animal and plant protein sources, with crystalline amino acid supplementation, were compared. The fish (15.7 [SE 0.12] g fish−1) were fed one of three isonitrogenous (41% protein) and isoenergetic (13 kJ g−1) diets for 60 days. Fish fed a diet with no fishmeal (D0; blood meal and soybean protein sources only) displayed the lowest specific growth rate (p < 0.001). Longer body lengths were achieved in fish fed a 50% fishmeal diet (D50; supplemented with poultry meal, bloodmeal, canola meal and soybean) (13.2 [SE 0.4] cm) compared with those fed either a 100% fishmeal diet (D100) (12.8 [SE 0.4] cm) or a diet with no fishmeal (D0) (12.1 [SE 0.08] cm) (p < 0.001). There were no differences in condition factor, hepatosomatic index (HSI) and feed conversion ratio (FCR) between fish fed diets D50 and D100; whereas fish fed diet D0 had a lower HSI and a higher FCR when compared with the other treatments (p < 0.01). The dietary protein source did not alter the gut microbiota of these fish. In conclusion, 50% replacement of dietary fishmeal with a favourable balance of meals processed from poultry, blood, canola and soybean improved length gain in juvenile dusky kob compared with those fed a diet with no fishmeal replacement. [ABSTRACT FROM AUTHOR]

Backgrounds: Chlorella is used popularly as dietary supplements. Various studies and researches have been done regarding the intervention of microalgae as foods since a long time ago. And, it is found that Chlorella have potential health benefits, in terms of their protein and antioxidant content. Thus, with an objective of formulating nutritional supplements, this algae are being harvested in artificial ponds on a large scale and could be used in different way such as feed supplemet or a replacement with a source of protein. Objectives: evaluate the effect of feed containing various ratios of Chlorella on some biological parameters in common carp. Methods: The experiment was conducted for 105 days and for these purpose 200 fingerlings common carp C. carpio L. were brought from a local aquarium fish in Iraq. Mean initial weight was 35.7g. The fish were acclimated to laboratory conditions and fed with control pellets (29% protein) prior to the feeding trials for 21 days in fish laboratory/ Dept. of Animal Sciences/ College of Agricultural Sciences/ University of Sulaimani. In T1 fish were fed a diet with 0 Chlorella gm/kg diet,while in T2, fish were fed a diet with 2.5 Chlorella gm/kg diet, T3 represents the third treatment, in which fish were fed on a diet with 5 Chlorella gm/kg diet, and in T4 fish were fed a diet with 7.5 Chlorella gm/kg diet. Results: The present study clearly showed that feeding algae as a feed additive to fish remarkably change the studied biological parameters, in Hepatosomatic index all treatments were significantly differ than the control, Spleenosomatic index the control and T4 were higher significantly than others, in Gonadosomatic index the T2 and T4 were differ significantly while T4 was significantly higher than other treatments in Kidneysomatic index. Fish weight without viscera and weight without viscera & head differ significantly among treatments with the addition of Chlorella the diet. Conclusion: Chlorella can be used as protein rich sources to replace fishmeal or as feeding additives in the diets of common carp fingerlings with different levels. Products that are safe and of good quality.

This study aims to determine various relationships between liver, gonad and body weights of the two pipefish species caught in two breeding seasons from the Bafa Lake (Muğla) coasts between 2014 -2016. Using beach seine-net in the lake, a total of 208 pipefish specimens (79 Synathus abaster and 129 Synathus acus) were sampled. L-W relationship and Fulton condition factor were W = 2E - 0.94.01, 0.035 ± 0.009 in S.abaster specimens. Also LW relationships and condition factor were W = 8E-0.93.83 , 0.033 ± 0.01 in S. acus. On the other hand mean ± SD of HSI and GSI values were 2.18 ± 1.65 and 7.69 ± 7.12 respectively. In S.acus values 3.22 ± 3.13 and 5.49 ± 5.12 as well. The decrease in HIS and K values, provides sufficient information to claim that species in the lake spend all energy requirement obtained with proper feeding to growth and gonad development.

The effect of industrial effluent on Hepatosomatic index and Gonadosomatic index of fish Labeo rohita was studied. In mature female Labeo rohita on exposure to the industrial effluent concentration marked toxicological alteration and reduction in Hepatosomatic index and Gonadosomatic index throughout the year . However in control group fish the value of GSI and HSI are increasing to seasonal variation. The maximum value of Gonadosomatic index and Hepatosomatic index was recorded in the pre-spawning phase. The reduction value of Gonadosomatic index and Hepatosomatic index is indirectly proportional to the industrial effluent concentration. The present study is useful for conservation, sustainable fishery management and the breeding programme of fish Labeo rohita. [ABSTRACT FROM AUTHOR]

Mortality of fish has long been recognized as the evident indication of pollution, nevertheless, the increasing low-level pollution may lead to a long-term decline and eventual extinction of fish stocks. This study investigates the impact of a point source pollution (El-Sail Drain) on the biological parameters of redbelly tilapia (Coptodon zillii) in the River Nile at Aswan, Egypt. The present results showed a significant variation of the physicochemical parameters and heavy metals of the River Nile waters in the vicinity of El-Sail Drain. On the other hand, metal concentrations in the gonads of C. zillii from the downstream of the pollution source were significantly higher than that of the unimpacted upstream area. The sex ratios of C. zillii varied in the two studied areas, where it was 1:1.38 in the unimpacted area and was 1:0.9 in the impacted area. While the GSI values of the impacted area were decreased significantly (p < 0.01) compared to that of the unimpacted area. As well, the fecundity of C. zillii was found to decrease due to their exposure to various metals in the impacted area. Based on the results of the present study, the evidenced low-level water pollution from El-Sail Drain was found to affect negatively the biological and reproduction features of C. zillii. [ABSTRACT FROM AUTHOR]

In this study, histological effects of water pollution to freshwater cyprinid, Alburnus mossulensis, was investigated. Water, sediment, and fish samples were taken from four stations in Karasu River (Erzurum, Turkey) between June and September in 2015-2016. In water and sediment samples, the concentrations of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, and Pb were detected. Histopathological changes in gill, liver, and kidney tissues were determined by degree of tissue change (DTC), and hepatosomatic index (HSI) was calculated. The mean concentrations of heavy metals in water and sediment samples were lower at station 4. The trend of some metal contents found in the fish was in increasing order of Zn < Cu < Cr < Pb. The observations on histopathology included cellular degeneration, congestion, dilatation, vacuolization, edema, vasodilatation, hyperplasia, hypertrophy, infiltration, melanomacrophage aggregates, glomerulopathy, fibrosis, and necrosis. It was observed that the DTC and HSI values in fish varied significantly from station to station. The results showed that the higher severity of histopathological alterations in the fish tissues was strongly correlated with agricultural and domestic activities in the area. [ABSTRACT FROM AUTHOR]

The poor state of cod in the Eastern Baltic is largely a consequence of biological changes in the stock during recent decades. One of several factors that may affect fish population dynamics is a high level of parasitic infection. Linear models were used to quantify the associations between two body condition factors, FCF and CF, and hepatosomatic index (HSI) with the level of nematode infection of cod liver. Parasitological analysis revealed the presence of nematodes representing the genera Contracaecum (the most abundant genus), Anisakis and Hysterothylacium. The level of cod infection with C. osculatum larvae was markedly higher than reported in previous studies undertaken over the past few decades. Body condition factors and HSI significantly decreased with increasing infection density (IFD, defined as the number of nematodes per gram of cod liver tissue). However, the correlation between FCF and HSI was rather low, indicating that they may respond differently to environmental conditions. The decline in both body condition factors in females was significantly higher than in males. The IFD close to 5 in females and 9 in males was associated with a decline in CF below the threshold of lethality. The indices used reflect the amount of accumulated energy reserves in fish and an increase in IFD is one of the factors leading to a reduction in these reserves. Damage of liver tissue by nematodes may negatively affect the physiology of this organ and its capacity to store the necessary level of energy reserves. • C. osculatum infection levels in cod are markedly higher than in earlier decades. • Condition factors significantly decrease with increasing infection density. • The hepatosomatic index is negatively correlated with infection density. [ABSTRACT FROM AUTHOR]

Immunity is an important component of invasion success since it enables invaders’ adaptation to conditions of the novel environment as they expand their range. Immune response of invaders may vary along the invasion range due to encountered parasites/microbial communities, conditions of the local environment, and ecological processes that arise during the range expansion. Here, we analyzed changes in the immune response along the invasion range of one of the most successful aquatic invaders, the signal crayfish, in the recently invaded Korana River, Croatia. We used several standard immune parameters (encapsulation response, hemocyte count, phenoloxidaze activity, and total prophenoloxidaze) to: i) compare immune response of the signal crayfish along its invasion range, and between species (comparison with co-occurring native narrow-clawed crayfish), and ii) analyze effects of specific predictors (water temperature, crayfish abundance, and body condition) on crayfish immune response changes. Immune response displayed species-specificity, differed significantly along the signal crayfish invasion range, and was mostly affected by water temperature and population abundance. Specific immune parameters showed density-dependent variation corresponding to increased investment in them during range expansion. Obtained results offer baseline insights for elucidating the role of immunocompetence in the invasion success of an invertebrate freshwater invader.

Fipronil is a relatively new insecticide in agriculture with health and environmental effects. This is the first report studying effect of fipronil on fish administered via intraperitoneal route. Intraperitoneal LD50 of fipronil in 16.3 g Caspian kutum, Rutilus frisii kutum, fingerlings was determined using a total of 133 fish in 19 tanks (7 fish/tank) including one control and 6 treatment groups (300, 450, 550, 650, 750, 850 mg/kg). Fish were injected intraperitoneally and monitored at 96 h. The LD50 of fipronil was 632 mg/kg in Caspian kutum. Sub-lethal test doses of 10, 20, and 30% of the LD50 at 96 h were used to assess the effect of fipronil on the fish’s liver. The blood plasma of 90 fish were used (18 at each test dose and in controls) on days 7 and 14 for biochemistry. The hepatosomatic index (HSI) of the livers were obtained and histopathology done on the same days. Pyknosis, sinusoid dilation and vacuolization were common histological changes, and these changes became more severe in a time and dose dependent manner. This dependence was also observed for HSI and the liver biochemical test (alanine and aspartate transaminase). Liver histological alterations showed that fipronil can be a potential factor in liver carcinoma.

Abstract Background Global trend of the introduction of high levels of relatively cheap carbohydrates to reduce the amount of costly protein in the aquatic animal feed production has affected the aquaculture of an economically important cyprinid fish, blunt snout bream (Megalobrama amblycephala). This dietary shift has resulted in increased prevalence of metabolic disorders, often causing economic losses. High dietary intake of carbohydrates, associated with obesity, is one of the major causes of non-alcoholic fatty liver disease (NAFLD) in humans. Results We have conducted an eight-week feeding trial to better understand how a high-carbohydrate diet (HCBD) affects the liver health in this fish. Hepatosomatic index and lipid content were significantly (P

Abstract: The objective of this work was to evaluate different feeding rates on the productive performance of cobia (Rachycentron canadum) grown in brackish waters. For the experiment, 1,600 juveniles were distributed in 16 enclosures installed in an estuarine pond. Four different feeding rates were evaluated: 1, 3, 5, and 7% live weight (LW) per day. The following performance parameters were assessed: survival, final biomass, specific growth rate, daily weight gain, apparent feed conversion, protein efficiency rate, lipid efficiency rate, and hepatosomatic index. Survival was greater than 80% at all feeding rates. The most efficient feed conversion rate was obtained with the feeding rate of 5% LW per day, which also resulted in better values for the hepatosomatic index. The rate of 5% LW per day provides a better productive performance for cobia in brackish waters.

Muscle and liver tissues of Lophius vomerinus off the coast of Namibia were analysed to investigated the influence of MeHg on the biological parameters of L. vomerinus by (i) determining if the variability in total MeHg concentrations is influenced by length, maturity status and sex, and (ii) assessing if there is a relationship between biological indices (Condition factor (K), Gonadosomatic Index (GSI) Hepatosomatic Index (HSI)) and MeHg concentrations. Correlations between total MeHg concentrations and fish length, K and HSI were observed. A weak positive correlation was observed between total MeHg and GSI for combined sex. Total MeHg concentration in tissues of L. vomerinus is significantly dependent on the maturity stages (p < 0.05). K was significantly inversely correlated with total MeHg in tissues of L. vomerinus. The evidence presented in this study suggests that MeHg in L. vomerinus tissues could be detrimental to both its physiology and population dynamics. • An increase in MeHg reduced the condition factor of Lophius vomerinus off the coast of Namibia. • Hepatosomatic Index was significantly influenced by accumulation of MeHg in L. vomerinus. • The MeHg concentration increased with the progress in the maturity stages of L. vomerinus. • Future studies should identify specific gonad and liver cells that might be affected by MeHg. [ABSTRACT FROM AUTHOR]