Higher Hepatosomatic Index Research Articles

Hermetia illucens Larvae Meal as Partial Fishmeal Replacement in Jade Perch Diet Cultured in Biofloc: Growth Performance, Feed Efficiency and Consumer Acceptance

A 12-week feeding trial on jade perch (Scortum barcoo) was conducted to evaluate the outcomes of partial substitution of fishmeal with black soldier fly larvae meal (BSFLM) in a biofloc system that requires minimal water exchange. The jade perch juveniles were subjected to three dietary treatments namely the 100% fishmeal (FM100), 50% BSFLM (BSF50), and a commercial diet (COM) with 20 individuals per treatment in triplicate tanks. Growth, feed efficiency, and body indices were measured throughout the feeding trial. There were no significant differences observed between the treatments in growth indicators such as the body weight gain (84.55 - 89.10 g), feed conversion ratio (1.77 - 1.87), specific growth rate (1.71 - 1.81 %/day), protein efficiency ratio (1.69 - 1.77), survival rate (90.00 - 98.48 %) and fillet yield (34.94 - 37.08 %). The condition factor is similar in all treatment groups ranging from 1.97 - 2.05. The crude protein and moisture content making up fish body composition are not statistically different among treatments, but higher crude lipids are obtained in the BSF50 (32.33 ± 5.27 g/kg) and COM (31.67 ± 2.76 g/kg). Higher hepatosomatic index (HSI) and visceral fat somatic index (VFSI) values were observed in BSF50 group at 3.13 ± 0.25 and 10.89 ± 1.68, respectively. Furthermore, sensory evaluation comparing the consumers' evaluation and acceptance of the fish cultured with the different dietary treatment and culture system shows that the group fed BSF50 and cultured in biofloc system received similar overall appreciation with the FM100 and COM group. In conclusion, BSFLM inclusion in the jade perch diet, combined with the biofloc system, is feasible to be explored further.

Growth performance and survivability of the Asian seabass Lates calcarifer (Bloch, 1790) reared under hyper-saline, hypo-saline and freshwater environments in a closed aquaculture system.

Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p<0.05). The highest WG (39.11±1.49 g), ADWG (1.00±0.12 g), SGR (8.74±0.03% d-1) and lowest FCR (0.96±0.20) were observed with T3 treatment, which was significantly higher compared to other treatment groups (p<0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index were found with T3 treatment, significantly higher than the other groups (p<0.05). No significant differences were found among the treatments in terms of survival rate (p>0.05), but the maximum survival rate (98.89±0.0%) was observed in the T3 and T2 treatments. The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition of Asian seabass juveniles in the T3 treatment group. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian seabass. Thus, the present study recommends 20 to 36 ppt salinity for the commercial farming of Asian seabass under a closed aquaculture system.

Sperm quality of Litopenaeus vannamei fed fresh or experimental food in two culture systems

AbstractThe growth of shrimp production through aquaculture has led to efforts to optimize processes such as nutrition during the prematuration and reproductive phases. This study sought an optimal culture system and diet to enhance the reproductive characteristics of male Litopenaeus vannamei during prematuration: this compared biofloc with clear water, and an experimental pellet (EP) with a mix of fresh food. Effects were measured in terms of shrimp survival, sperm quality, immunological parameters including prophenoloxidase (ProPO) and hemocyte count, nutritional condition measured as metabolites in hemolymph, hepatopancreas, and reproductive tract, oxidative stress biomarkers in the hepatopancreas and reproductive tract, and relative expression of superoxide dismutase, catalase, glutathione peroxidase, ProPO, alpha2‐macroglobulin and caspase in reproductive tract. Survival was higher with pellets (100%) than with fresh food (87%). Shrimp that were fed pellets had a higher hepatosomatic index, higher nutrient concentration in the hepatopancreas, and a higher antioxidant activity in the reproductive tract. Notably, sperm quality remained similar regardless of culture system or diet. These promising results should be ratified with a bioeconomic study to check the feasibility of hatcheries to use monosex tanks and feeding the males with EPs.

Insulin-like growth factor-1 (Igf1) signaling responses to food consumption after fasting in the Pacific rockfish Sebastes carnatus

Fish adjust rates of somatic growth in the face of changing food consumption. As in other vertebrates, growth in fish is regulated by the growth hormone (Gh)/insulin-like growth factor-1 (Igf1) endocrine axis, and changes in food intake impact growth via alterations to Gh/Igf1 signaling. Understanding the time course by which the Gh/Igf1 axis responds to food consumption is crucial to predict how rapidly changes in food abundance might lead to altered growth dynamics. Here, we looked at the response times of plasma Igf1 and liver Igf1 signaling-associated gene expression to refeeding after food deprivation in juvenile gopher rockfish (Sebastes carnatus), one of several species of northern Pacific Ocean Sebastes rockfishes targeted by fisheries or utilized for aquaculture. Gopher rockfish were fasted for 30 d, after which a subset was fed to satiation for 2 h, while other rockfish continued to be fasted. Refed fish exhibited higher hepatosomatic index (HSI) values and increased Igf1 after food consumption. Gene transcripts for Gh receptor 1 (ghr1), but not ghr2, increased in the liver 2-4 d after eating. Transcripts encoding igf1also increased in the liver of refed fish by 4 d after feeding, only to return to levels similar as continually fasted rockfish by 9 d after feeding. Liver mRNA abundances for Igf binding protein (Igfbp) genes igfbp1a, igfbp1b, and igfbp3a declined within 2 d of feeding. These findings provide evidence that circulating Igf1 in rockfish reflects a fish's feeding experience within the previous few days, and suggest that feeding-induced increases in Igf1 are being mediated in part by altered liver sensitivity to Gh due to upregulated Gh receptor 1 expression.

Dietary effect of grape (Vitis vinifera) seed extract mitigates hepatic disorders caused by oxidized fish oil in rainbow trout (Oncorhynchus mykiss)

The major goal of this study was to determine the effect of grape seed extract (GSE) on liver damage in rainbow trout (Oncorhynchus mykiss) that was caused by the consumption of dietary oxidized fish oil (OFO). Rainbow trout were fed six different experimental diets coded OX-GSE 0 (OFO diet), OX-GSE 1 (OFO and 0.1% GSE), OX-GSE 3 (OFO and 0.3% GSE), GSE 0 (fresh fish oil and 0.0% GSE), GSE 1 (fresh fish oil and 0.1% GSE), and GSE 3 (fresh fish oil and 0.3% GSE) for 30days. The lowest % hepatosomatic index (HSI) result was calculated in fish fed with OX-GSE 0 and the highest HSI was determined in fish fed with GSE 1 diets (p < 0.05). Histopathologically, hydropic degeneration in hepatocytes significantly increased OX-GSE 0 and GSE 3 compared to GSE 1 diets (p < 0.05). Deposition of lipid droplets in hepatocytes was significantly increased in OX-GSE 0 and OX-GSE 3 groups than others (p < 0.05). Liver biochemistry parameters such as superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) were significantly affected by OX and GSE treatments (p < 0.05). There were significant differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) among the liver enzymes analyzed in serum in OX and GSE (p < 0.05), meanwhile no difference was observed in lactate dehydrogenase (LDH) values between groups (p > 0.05). In conclusion, liver biochemistry and histopathology of rainbow trout consuming diets containing oxidized fish oil were negatively affected. However, it was determined that the supplementation of 0.1% GSE to the diet had a significant ameliorative role in these adverse effects.

Response of Nile tilapia under biofloc system to floating or sinking feed and feeding rates: Water quality, plankton community, growth, intestinal enzymes, serum biochemical and antioxidant status

The current study examined the combined effects of feeding rates and feeding types on the water quality, growth performance, digestive enzymes, blood parameters, and liver antioxidant enzymes of Nile tilapia (Oreochromis niloticus) fingerlings reared under a biofloc system. A 3 × 2 factorial experimental design was used with three feeding rates (2%, 3%, and 4%) and two feeding types (sinking or floating feed), comprising six treatments with three replicates. Fingerlings with an initial body weight of 4.50 ± 0.25 g were stocked in eighteen circular plastic tanks (0.5 m3) at a stocking density of 35 fish per tank fed three times a day at 10:00, 12:00 and 15:00. Starch was added to all treatments as an organic carbon source at a C/N ratio of 10:1. The phytoplankton community was determined to consist of twenty-two species, including individuals from the classes Cyanobacteria, Chlorophyceae, and Bacillariophyta. The most common phytoplankton classes were Chlorophyceae, followed by Cyanobacteria, and fish-fed floating feed at a feeding rate of 2% of total biomass yielded the greatest number of phytoplankton communities. Eight zooplankton species belonging to rotifers and protozoa were identified during this experiment. The highest values of final body weight, weight gain, and specific growth rate were recorded for a fish-fed floating diet with the highest feeding rate (4% of biomass). The highest hepatosomatic index (HIS) was detected in a fish-fed floating diet at a rate of 4% of total biomass. Though fish-fed sinking feed with a 4% biomass feeding rate presented the highest spleen index (SI). The highest significant (P < 0.05) level of amylase was found in fish-fed sinking feed at a 4% feeding rate. While lipase activity was higher (P < 0.05) in the group fed floating feed at a feeding rate of 3% of total biomass. Feeding rates, feed types, and their interactions had no appreciable effect (P > 0.05) on hemoglobin (Hb), hematocrit (Hct), and red blood cells (RBCs). Feeding rate, feed type, and their interactions had no significant impact (P > 0.05) on serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), or albumin, but feeding rates or feed types had an effect (P < 0.05) on total protein and globulin (P < 0.05). The highest levels of growth hormone (GH) (P < 0.05) were found in fish-fed either sinking feed at a feeding rate of 2% or floated feed at a feeding rate of 3% of total biomass. The fish group fed floating or sinking feed at a feeding rate of 2%, floating feed at 3%, and sinking feed at 4% recorded the highest high-density lipoprotein (HDL-C) values with an insignificant difference. Considering the liver's antioxidant enzymes, the highest catalase (CAT) and glutathione (GSH) levels were shown in fish that received either sinking or floating feed at feeding rates of 2% and 3%, respectively. Whereas, the lowest melanodialdehyde (MDA) was found in fish-fed sinking feed at a feeding rate of 3% of total biomass. According to the study's findings, the biofloc system significantly improved both the water quality and the efficiency of Nile tilapia. In addition, feeding tilapia 4% floating feed resulted in maximum feed consumption with minimal waste, improved nutritional efficiency and feed conversion efficiency, lowered production costs, and lessened water pollution.

A study of the potential effect of dietary fishmeal replacement with cricket meal (Gryllus bimaculatus) on growth performance, blood health, liver antioxidant activities, intestinal microbiota and immune-related gene expression of juvenile channel catfish

Studies have shown that insect meals can partially or completely replace fish meal (FM) that are commonly used in aquaculture. Therefore, a 10-week feeding trail was done to test the potential impacts of replacement of FM with cricket meal (CM) on the growth performance, body composition, blood health, liver antioxidant activities, intestinal microbiota and immune reaction of juvenile channel catfish. Five isonitrogenous (crude protein 35%) and isocaloric (19 MJ/kg−1) diets were formulated to have 0%, 25%, 50%,75% and 100% CM and named T0, T25, T50, T75 and T100 groups, respectively. Final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) in fish fed T50 and T75 groups were considerably elevated compared with fish fed control T0 group. Higher hepatosomatic index (HSI) was found in fish fed T50, T75 and T100 groups compared with fish fed control T0 group. The moisture and crude protein contents in fish fed T75 and T100 groups were significantly increased than that of fish fed control T0 group. Hematological parameters examination of juvenile channel catfish demonstrated that hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) showed significantly higher values with increasing content of CM in dietary fish fed groups. Malondialdehyde (MDA) content and glutathione peroxidase (GPx) activity level were highest in fish fed T75 group, respectively. Catalase (CAT) activity in fish fed T50 to T100 groups was significantly greater than those of fish fed control T0 and fish fed T25 groups. Intestinal microbiota sequencing analysis showed that Chao1, Shannon, Simpson indices, and Good’s coverage in fish fed control T0, fish fed T50 and T100 groups were not significantly affected. Intestinal microbiota analysis showed the relative abundance of Proteobacteria and Firmicutes were dominated at the phyla level. Moreover, with an increasing of CM replacement, the abundance of a prominent pathogenic bacterial Acinetobacter was reduced at the genus level although no significant differences. The immune-related gene expression levels of IL-1β, IL-8, IL-10 and HIF1α were up-regulated in intestine when CM replacement increased from 0% to 75%, and higher levels were observed in fish fed T75 group comparing to others. The expression levels of TNF-α, IL-22 and IFN-γ were significantly elevated in fish fed T100 group. Notably, fish fed T50 to T100 groups down-regulated the expression of NF-κB compared to the other groups. To conclude, the present findings show that CM could enhance growth performance, improving blood health and liver antioxidant capacity, and substantial alterations in intestinal microbial composition of juvenile channel catfish, suggesting that FM could be replaced by CM as insect protein source in channel catfish diet.

The Impact of Addition of Soybean Oil to Increase the Growth, EPA and HSI in Biofloc Catfish

This study aimed to determine the level of increasing of omega-3 fatty acids EPA, Hepatosomatic Index (HSI), Specific Growth Rates (SGR), and Average Daily Growth (ADG) with the addition of soybean oil to feed as supplement. This research method uses a Complete Randomized Design (CRD) consisting of 4 treatments and 4 tests. The different concentration of soybean oil in the feed were considered as treatment, A (0%); B (2%); C (4%); and D (6%). The test fish used was catfish (Clarias sp) from Bandung Regency, West Java. Feed as much as 2.5% of the biomass weight is given 2 times a day, namely at 07 a.m and 16 p.m for 30 days in a biofloc tank. The conclusion of this study was that the addition of soybean oil showed the best result is in the addition of 4% soybean oil to the feed. The dose showed that the addition of soybean oil as much as 4% to the feed was able to have the best influence on the increase in Omega-3 eicosapentaenoic acid/EPA fatty acids by 25 mg/100g with the highest Hepatosomatic Index (HSI) value of 1.52 ± 0.11, the best Specific Growth rate (SGR) value of 1.1% and Average Daily Growth (ADG) value of 0.27%.

Comparison of edible yield and quality of female Chinese mitten crab between two-year-old and three-year-old

To expand the new germplasm of Chinese mitten crab (Eriocheir sinensis) and explain its quality characteristics, this study used two-year-old mature female E. sinensis (TWC) as the control to explore the differences in edible yield, color, proximate composition, fatty acids, free amino acids and mineral elements of three-year-old mature female E. sinensis (THC). TWC had a significantly higher hepatosomatic index (HSI) but a lower gonadosomatic index (GSI) than THC (P < 0.05). The eicosapentaenoic acid (EPA) content in the hepatopancreas, ovary and muscle tissues of TWC were higher than those of THC. However, the content of docosahexaenoic acid (DHA), arachidonic acid (ARA), polyunsaturated fatty acids (PUFA), total essential fatty acids (ΣEFA), total highly unsaturated fatty acids (ΣHUFA), Σn-6 PUFA and DHA/EPA were lower than those of THC. Total essential free amino acids (ΣEFAA), total free amino acids (ΣFAA) and percentage of ∑EFAA to ∑FAA (PETFAA) in the hepatopancreas, ΣEFAA and PETFAA in the ovary and ΣFAA in the muscle of TWC were higher than those of THC (P > 0.05). The values of total umami values (ΣTUV) and total sweetness values (ΣTSV) in the hepatopancreas, ovary and muscle tissue and total bitterness values (ΣTBV) in the hepatopancreas and muscle of TWC were higher than those of THC. Except for the higher Zn in TWC, the contents of the other elements measured were lower than those in THC. Overall, the edible yield and quality of THC was greater than that of the TWC, and THC was a new high-quality germplasm of E. sinensis.

Reproductive biology of the whitespotted eagle ray Aetobatus narinari (Myliobatiformes) captured in the coast of Paraíba and Pernambuco, Brazil.

The present study analysed aspects of reproductive biology based on macroscopic and microscopic structures of whitespotted eagle ray Aetobatus narinari captured by artisanal fishing off the coast of Paraíba and Pernambuco (7° 30'S, 34° 49'W; 7° 47'S, 34° 51'W), northeast Brazil. Of the 71 individuals in the sample, 55% were female (disc width - WD : 532-1698 mm) and 45% were male (WD : 442-1410 mm). The body size at which 50% of the individuals are mature (WD50 ) for males was 1155.8 mm; the clasper length varied between 24 and 184 mm. The WD50 for females was 1293.9 mm; the diameter of the largest vitellogenic follicle varied between 11 and 31 mm; and only the left ovary and uterus were functional. The microanatomy of the reproductive tract of males and females agrees with that of other elasmobranch species. In males, the highest hepato-somatic index (IH ) average and gonado-somatic index (IG ) average occurred in the third bimester of the year, whereas in females the highest values (average IH and IG , respectively) were in the second bimester of the year. Based on the information on reproduction of A. narinari from this study, it will be possible to contribute to the correct management and protection of this species.

Potential effects of dietary ZnO supported on kaolinite (ZnO-K) to improve biological parameters, reproduction indices, lipid profile and antioxidant enzymes activities for broodstock of Nile tilapia (Oreochromis niloticus)

The current study was carried out to study the effect of zinc oxide (ZnO) supported on kaolinite (ZnO-K) on biological parameters, reproduction indices, semen quality, lipid profile and oxidative biomarkers for broodstock of Nile tilapia. Four tested diets were formulated; Diet 1 was control diet without addition. Diet 2, Diet 3 Diet 4 were supplemented with 30, 60 and 90 mg ZnO-K kg−1, respectively. Sixty females with average weight of 135.19 ± 3.91 g and twenty-four males with average weight of 212.51 ± 13.4 g of Nile tilapia (Oreochromis niloticus) were used. All broodstock fish were hand fed experimental diets up to apparent satiation three times daily (9:00, 12.00 and 14.00) for 4 weeks before mating. The highest hepatosomatic index (HSI %) and gonadosomatic index (GSI %) (P < 0.05) of male and female were recorded by fish fed Diet 4. The highest reproductive performance of female includes total absolute relative fecundity and fry survival (P < 0.05) were recorded for fish fed by Diet 4. Regarding semen quality of male, the highest pH, motility and sperm concentration (P < 0.05) were recorded by fish fed diet supplemented with ZnO-K kg−1 especially D4. Serum plasma levels of triglyceride cholesterol and high-density lipoprotein (HDL-C) (P < 0.05) were at higher levels of broodstock male and female fed by D4. The levels of catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD) enzymes were significantly increased (P < 0.05) in the liver of broodstock male and female fed diet supplemented with higher levels of ZnO-K (D4) while, the highest values of alkaline phosphatase (ALP) (P < 0.05) and lower malondialdehyde (MDA) were recorded for fish fed diet without addition (D1). The present result indicated that dietary supplemented with ZnO supported on kaolinite (ZnO-K) at 60 or 90 mg kg−1 has a prominent potential in improving biological parameters and reproduction performance, semen quality, serum lipid metabolism and enzymes activates of Nile tilapia broodstock.

Ebu Kefalinin Üreme Biyolojisi, Planiliza abu (Heckel, 1843), Karun Nehri, Güneybatı İran

Some aspects of the reproductive biology of Planiliza abu (Mugilidae) were investigated by collecting of 428 specimens caught with trawl by local fishermen from Karun River, Ahwaz, from November 2016 to September 2017. Total length for males ranged between 10-17.1 (13.6±1.26 SD) cm and for females, between 10.5-17.3 (13.44±1.35) cm. The age range of fish in both sexes was between 0+-7+ years and the most abundant age group was the 4+. Sex ratio in the studied fish was equal (P&amp;gt;0.05). The mean egg diameter was significantly different (P&amp;lt;0.05) in different months and the individual size ranged between 0.12 and 0.57 mm. The absolute fecundity ranged from 3600 to 48600 eggs and the relative fecundity from 120 to 900 eggs per 1 g of body weight. The highest hepatosomatic index in females was in February during yolk vitellogenesis (1.89). Based on gonadosomatic index, egg diameter and monthly distribution of ovarian maturation stages, the spawning season of this fish is long, but peaks in February (GSI 12.35) and March (GSI 12.18). This species appears to have a group synchrony reproductive pattern.

Reduced fatty acid β-oxidation improves glucose catabolism and liver health in Nile tilapia (Oreochromis niloticus) juveniles fed a high-starch diet

Fish are poor users of dietary carbohydrates and often display prolonged hyperglycemia and fat deposition after feeding high digestible carbohydrate diets. Recently, fatty acid β-oxidation (FAO) inhibition has been reported to increase glucose oxidation in fish. Therefore, this study tested the assumption that the inhibition of FAO with mildronate (MD, a carnitine synthesis inhibitor) might also increase glucose utilization and alleviate adverse effects induced by high starch diet (HSD) in Nile tilapia, Oreochromis niloticus. Nile tilapia juveniles (6.13 ± 0.11 g) were cultured in nine 200-L tanks (30 fish per tank) and divided into three groups (three tanks per group). The fish were fed twice a day (9:00 and 18:30) at 4% body weight by using a normal starch diet (NSD, 30% corn starch), a HSD (45% corn starch), or a HSD supplemented with MD (25 g/kg of diet, HSD + MD) for eight weeks. These three feeds contained approximately 35.8% protein and 6.4% lipid. The fish each tank were weighed every two weeks, and the feeding amount was adjusted accordingly. After the feeding trial, the fish fed on HSD showed higher hepatosomatic index (HSI), visceral somatic index (VSI), serum triglyceride concentration and whole-body and tissue (liver and muscle) lipid contents than those fed on NSD. The fish fed on HSD also had higher relative area of vacuolation in the liver, hepatic malondialdehyde (MDA) content, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in the serum than those fed on NSD. Moreover, the fish fed on HSD increased serum glucose and insulin concentrations, and hepatic lactate, pyruvate and glycogen contents, but reduced whole-body protein content and dietary protein utilization than those fed on NSD, indicating that HSD induced fat deposition, liver damage, glucose intolerance and lowered protein-sparing effect. However, the fish fed on HSD + MD decreased hepatic carnitine content and FAO activity, attenuated the indexes related to fat deposition and liver damage, improved blood glucose clearance and whole-body protein deposition than those fed on HSD, suggesting that the adverse effects caused by HSD were reversed after FAO inhibition. Furthermore, the fish fed on HSD down-regulated the expression of genes associated with glucose uptake, glycolysis, FAO process, and lipolysis compared to those fed on HSD + MD and NSD, yet up-regulated lipogenic and proteolytic genes. These data suggested that inhibition of FAO improved glucose utilization and alleviated the HSD-induced adverse effects in Nile tilapia. This work demonstrates that, modifying mitochondrial FAO activity regulates the ability of fish to adapt to HSD intake through remodeling energy homeostasis. Our study provides new insights into improving carbohydrate utilization in aquatic animals.

Growth, physiological, biochemical, and molecular responses of Pacific white shrimp Litopenaeus vannamei fed different levels of dietary selenium

This study investigated the effects of different levels of dietary selenium (Se) on the growth, antioxidant capacity, hepatopancreas health, and transcriptional-level responses of Litopenaeus vannamei. Sodium selenite was added to basal diet formulations at 0, 0.2, 0.4, and 0.8 mg/kg, with final Se concentrations of 0.13, 0.20, 0.45, and 0.81 mg/kg, respectively. Shrimp were fed the experimental diets for 8 weeks, after which the following parameters were measured: growth performance, antioxidant enzymes activity, ALT, AST activity, endoplasmic reticulum stress and transcriptome. Shrimp fed the 0.45 and 0.81 mg/kg Se diets (P < 0.05) showed the highest weight gain, shrimp fed the 0.13 mg/kg Se diet had the highest hepatosomatic index (P < 0.05), and the endoplasmic reticulum stress related genes were down-regulated (P < 0.05) in shrimp fed the 0.45 mg/kg Se diet. Antioxidant enzyme activity (SOD, CAT, and GPx) was enhanced with the increase in the Se level. The transcriptome results showed that glycine, serine, and threonine metabolism, the pentose phosphate pathway, and ascorbate and aldarate metabolism were enriched in shrimp fed the 0.45 mg/kg Se diet, while focal adhesions, gap junctions, tight junctions, and adhesion junctions were found in shrimp fed the 0.13 and 0.81 mg/kg Se diets. Co-expression analysis showed that genes PINK1 and Innexin (among others), were involved in the influence of Se levels on shrimp. Our results suggested that Se supplementation improved the growth and antioxidant capacity of L. vannamei by promoting the biosynthesis of glutathione and enhancing the activity of antioxidant enzymes. However, high levels of dietary Se can cause endoplasmic reticulum stress and hepatopancreas tissue damage.

Effect of dietary lipid on growth, body composition, serum biochemistry and hepatic metabolite alteration in Chinese rice field eel (Monopterus albus) fingerlings

Five isonitrogenous and isocaloric diets containing dietary lipid concentrations from 71.90 to 142.70 g/kg were formulated and fed to Chinese rice field eel Monopterus albus fingerlings (5.00 ± 0.50 g). The highest values of weight gain, specific growth rate (SGR), together with the lowest feed conversion ratio (FCR) were found in fish fed with 89.10 g/kg lipid diet. Fish fed with 71.90 g/kg diet (F1) had higher hepatosomatic index, viscerosomatic index and whole‐body crude lipid than fish in the other four treatments (p < .05). Plasma concentration of triacylglycerol and the activity of alanine aminotransferase were also higher in fish fed with F1 diet. Whole‐body fatty acid profile varied exclusively, but with a stable value of n−3/n−6 ratio. Gas chromatography–mass spectrometry‐based metabolomics identified eighteen differential metabolites (including idose, alanine, glutamic acid, serine and hypotaurine) in liver affected by dietary lipid content using PLS‐DA analysis. The subsequent pathway enrichment revealed ten affected pathways, with the top three pathways being glycine, serine and threonine metabolism; starch and sucrose metabolism; and D‐glutamine and D‐glutamate metabolism. The broken‐line model of SGR suggested that a dietary lipid concentration of 83.50 g/kg was appropriate for M. albus fingerlings.

PENGARUH INJEKSI HORMON HUMAN CORIONIC GONADOTROPIN (hCG) TERHADAP PERKEMBANGAN GONAD IKAN KEBALI (Oesteochilus Schlegeli Blkr)

The purpose of this study is to determine the optimal dose of hCG homrone on gonad maturation of parent prospective of kebali fish through regular injection. The research was carried out in Aquatic Environment Laboratory of Fisheries and Marine Science Faculty, Universitas Muhammadiyah Pontianak and Floating Net Cage (KJA) in Kelurahan Parit Mayor of Pontianak, that was carried out for 60 days. The expermental design used was a randomized block design (RBD) consisting of 3 groups and each group consisted of 6 treatments. As a treatment is hCG hormone was injected periodically from doses of 0 to 250 IU/kg of fish. Variables observed were Gonad Maturity Level (TKG), Gonado Somatic Index (GSI), Hepato Somatic Index (HSI), fecundity and eggs diameter. The results showed a dose of 150 until 250 IU/kg of fish can reach TKG IV with a greater proportion, a dose of 100 IU/kg of fish can reach TKG III, while the doses below only reach TKG I and II. The average value of HSI in each treatment was 0.74-1.57% and the GSI value is 1.64-4.51% with the highest HSI and GSI achieved at hCG injection with a dose of 150 IU/kg of fish that was with an index value of 1.57% and 4.51% respectively. The average of fish fecundity at hCG hormone doses of 100–150 IU/kg of fish ranged from 11,592–18,059 eggs, with the highest fecundity (18,059 eggs) achieved at the hormone dose of 250 IU/kg of fish. The range of eggs diameter produced after gonad maturation were 0.07–0.37 mm, hCG injection treatments of 150–250 IU/kg generally produces eggs that are 0.24–0.31 mm in size, and the injection dose was 250 IU/kg in part large eggs have a diameter of 0.28–0.31 mm. Water quality during the study was quite supportive for the maturation process of the ovary. Periodic injection of hCG hormone at a dose of 150 IU / kg of fish is the best dose for gonad maturation of kebali fish.

Effect of different carbohydrate-to-lipid ratios elicits growth, feed utilization, lipid deposition and lipogenic enzyme activity in striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) fingerlings

This study evaluated the effects of diets containing various carbohydrate-to-lipid (CHO L-1) ratios on growth performance, nutrient utilization body indices and hepatic lipogenic enzyme (malic enzyme, 6-phosphogluconate dehydrogenase and fatty acid synthase) activities. Triplicate groups of Pangasianodon hypophthalmus fingerlings were fed eight isoenergetic and isonitrogenous diets with different carbohydrate-to-lipid ratios (0.51, 0.79, 1.12, 1.79, 2.41, 3.24, 4.43 and 7.62). Higher body fat deposition and lower growth performance were observed in P. hypophthalmus fingerlings fed with high-lipid diet than those fed with high-carbohydrate diet. The fish fed the diet with 7.62 CHO L-1 ratio exhibited significantly (p<0.05) higher hepatosomatic index compared to those fed higher lipid diets (0.51 and 0.79). High dietary carbohydrate level significantly increased (p<0.05) the activities of malic, 6-phosphogluconate dehydrogenase and fatty acid synthase enzyme. Based on the second-order polynomial regression analysis of weight gain, the optimal dietary carbohydrate and lipid contents for P. hypophthalmus fingerling were 304 and 103 g kg−1, respectively, which correspond to a dietary CHO L-1 ratio of 2.95.

Effects of replacement of fish meal by poultry by-product meal on growth performance and gene expression involved in protein metabolism for juvenile black sea bream (Acanthoparus schlegelii)

An 8-week feeding trial was conducted to evaluate the effects of replacement of fish meal (FM) with poultry by-product meal (PBM) on growth performance, feed utilization and expression of genes involved in protein metabolism in juvenile black sea bream (Acanthoparus schlegelii). Six isonitrogenous (42%) and isolipidic (11%) experimental diets were formulated to replace 0% (control diet), 10%, 20%, 30%, 40% and 60% protein from FM with PBM. All the diets except the control diet were supplemented with lysine and methionine to keep same lysine and methionine levels among all diets. A total of 360 fish (approximately initial weight, 0.46 ± 0.02 g) were randomly stocked and sorted in 18,300-L cylindrical fiberglass tanks, each diet was randomly assigned to triplicate groups of 20 juvenile black sea bream and fed twice each day to apparent satiation. The results showed that survival ranged from 88.33 to 93.33%, and there were no significant differences among all treatments (p > .05). Final body weight (FBW) and percent weight gain (PWG) significantly increased with dietary replacement levels of FM with PBM increasing from 0% to 30%, and significantly decreased when replacement of FM with PBM further increased from 30% to 60% (p < .05), fish fed the 30% replacement of FM with PBM diet had higher FBW and PWG than those fed the other diets. Based on PWG against replacement levels of FM with PBM, A two-slope broken-line model analysis indicated that the optimal replacement of FM with FBM is to be 28.30%. Proximate composition in whole body did not show significant differences among all dietary treatments (p > .05). Higher hepatosomatic index (HSI) was observed in fish fed the 30% replacement of FM with PBM compared to the control and other diets, however, viscerosomatic index (VSI) and condition factor (CF) were not significantly influenced by the replacement of FM with PBM(p > .05). Fish fed the diet containing 30% replacement of FM with PBM had higher lysine and methionine concentration in muscles than those fed the other diets, however, other essential or non-essential amino acids in muscle were not significantly affected by dietary replacement of FM with PBM. The relative expressions of igf1, tor, s6k1, pi3k and akt were significantly up-regulated when replacement levels of FM with PBM increased from 0% to 30%, however, the expression levels of these genes significantly down-regulated with the further increase of replacement level of FM by PBM (p < .05). Moreover, the lowest expression of 4e-bp2 was occurred at fish fed the 30% replacement of FM with PBM among all treatments. In summary, the results of present study indicated that dietary PBM supplementation could be an alternative protein source for black sea bream, and 30% replacement of FM with PBM could improve growth and up-regulate the relative expression of genes involved in protein metabolism.

Histologic examination and transcriptome analysis uncovered liver damage in largemouth bass from formulated diets

As a commercial carnassial fish, largemouth bass (Micropterus salmoides) consumes a large amount of forage fish as food annually. To reduce the use of forage fish, a formulated diet was utilized in a largemouth bass culture. Although they have been improved upon for 10 years, formulated diets still cannot meet the nutritional needs of largemouth bass. The formulated diet and forage fish were separately used to feed fish in an experimental group (FDG) and control group (FFG) to investigate the effects of a commercial formulated diet on the growth performance and liver histomorphology and transcriptomics of largemouth bass. After the 8-month feeding trial, fish fed the formulated diet exhibited a significantly lower weight gain rate (WGR) and specific growth rate (SGR) but a higher hepatosomatic index (HSI) and hepatocyte vacuolization score. A further transcriptomic difference analysis demonstrated all of the physiological changes in the process of liver injury caused by the formulated diet. Several key genes involved in the process of liver disease, including gk (glucokinase), pck (phosphoenolpyruvate carboxykinase), acetyl-CoA acetyltransferase cytosolic-like (acat cytosolic-like), type-2 ice-structuring protein (type-2 isp), tf (transferrin), col6a3 (collagen type VI alpha 3), and TBT-bp (tributyltin-binding protein), showed significant differences in their expression patterns between the two diet groups. KEGG analysis showed that the differentially expressed genes in both females and males were involved in important pathways, including glycolysis, the citrate cycle (the TCA cycle), pathogenic E. coli infection and fatty acid biosynthesis. The results suggest that the extra carbohydrates in the formulated diet were transformed into fatty acids and that the synthesized fatty acids with the lipids in the formulated diet accumulated heavily in the liver, leading to inflammation and liver injury in largemouth bass.

Fish biomarkers from a different perspective: evidence of adaptive strategy of Abramis brama (L.) to chemical stress

BackgroundA prerequisite for long-term survival of populations under multi-stress conditions is their capacity to set up efficient adaptive strategies. However, changes in the activity of molecular biomarkers have been for decades considered as early signals of the deterioration of the fish health and evidence of stress-related adverse biological effects. The aim of this study was to show that such changes actually represent adaptive response of fish to chemical stress. Gene expression and enzyme activity level in liver and brain of specimens from two populations of Abramis brama from contrasted habitats (nature reserve and urban) were examined. Selected parameters included biomarkers of general stress, antioxidative defence, xenobiotic metabolism, endocrine disruption, glucose homeostasis, iron homeostasis, and neurotoxicity.ResultsExposure of A. brama population from urban area to chemical stress was confirmed by assessment of chronic toxic pressure at fish habitats using Toxic Unit approach. The most pronounced response to chemical stress is observed through the activation of antioxidative defence mechanisms in brain and liver at gene and enzyme activity level, high biotransformation capacity of liver, and activation of mechanisms that will meet energy demands and compensate for the metabolic costs of the response to toxicants (higher expression of genes related to glucose homeostasis in the exposed population). Higher hepatosomatic index in the exposed population implies liver hypertrophy due to increased functional load caused by pollution. Body condition factors indicate good overall condition of both fish populations and confirm high efficacy of mobilized adaptation mechanisms in the exposed population.ConclusionsThe study provided the first data on basal expression of a number of genes in A. brama, potentially valuable for biomonitoring studies in absence of clear pollution gradient and/or reference sites (conditions). The study highlights importance of newly identified roles of various genes and proteins, typically considered as biomarkers of effects, and shows that changes in these parameters do not necessarily indicate the deterioration of the fish health. Such changes should be considered as adaptive response to chemical stress, rather than direct proof of ecological impact of pollution in situ.