Efficacy of nutritional selenium nanoparticles on growth performance, immune response, antioxidant capacity, expression of growth and immune-related genes, and post-stress recovery in juvenile Sobaity seabream (Sparidentex hasta).

This study evaluated the impacts of nano-Se on the growth, immunity, antioxidant capacity, physiological parameters, gene expression, and stress resistance of fingerling Sobaity seabream (Sparidentex hasta). The fish with an average weight of 21.5 ± 0.1 g were divided into four treatment groups in triplicates that received one of the test diets supplemented with varying levels of nano-Se: 0 (control), 0.5 (Se-0.5), 1 (Se-1), and 2 (Se-2) mg/Kg for 60 days. The results showed that final weight, weight gain rate, specific growth rate, feed intake, and feed conversion ratio improved with significant linear and quadratic trends (P < 0.05) in response to nano-Se-supplemented diets, and the best values were measured in the Se-2 group. Superoxide dismutase activity level remained unaffected among the four groups (P > 0.05). Catalase activity increased in nano-Se-supplemented groups, with the highest level measured in fish fed the Se-0.5 diet. Glutathione peroxidase activity levels were not significantly different between the control and nano-Se groups, but the lowest malondialdehyde concentration was detected in the Se-2 group. Nano-Se had no marked effect on total plasma Ig levels; however, the highest lysozyme activity and alternative complement activity (ACH50) were observed in the Se-0.5 and Se-2 groups, respectively. No significant differences (P > 0.05) were observed in plasma total protein, albumin, globulin, triglyceride, and thyroid hormone (T3 and T4) contents among the groups. However, the lowest cholesterol and low-density lipoprotein values and the highest high-density lipoprotein concentration were measured in the Se-2 group. The Se-0.5 and Se-1 groups exhibited significantly lower levels of aspartate aminotransferase activity, and the lowest alkaline phosphatase activity level was detected in the Se-1 group. The expression level of insulin-like growth factor I gene in all nano-Se-fed groups was significantly higher than the control. Also, the expression of interleukin-1ß and lysozyme genes was significantly upregulated in nano-Se-supplemented groups, with the highest values in the Se-2 group. Following acute crowding stress, plasma cortisol and lactate levels at all post-stress time intervals were not significantly different among the experimental groups. Fish fed the Se-0.5 and Se-2 diets tended to have lower plasma glucose concentrations than other groups. In conclusion, dietary nano-Se at 2 mg/kg is recommended to promote growth performance and enhance antioxidant and immune parameters in Sobaity juveniles.

The effect of bisphenol A on antioxidant defense and the structure and function of the liver of Siberian sturgeon (Acipenser baerii).

The present study was conducted to investigate the biochemical and histological changes of liver tissue in Siberian sturgeon (Acipenser baerii) exposed to different doses of bisphenol A (BPA). One hundred and eighty pieces of 1-year-old A. baerii with an average weight of 200-250 g bought and randomly distributed in 18 tanks (n = 10). After 2 weeks of adaptation, the fish received intraperitoneal injections of 1, 10, and 100 µg/g/week BPA and µg/g/week of 17ß-estradiol intraperitoneally. The solvent control group received only peanut oil, while the control group did not receive any injections. In order to investigate histological changes of the liver, after 2 weeks the liver samples were taken, fixed in 10% formalin solution and slides prepared by routine histological methods. For assaying antioxidant defense status, the liver tissue from three fish of each replicates was captured and after homogenization, activity of catalase, superoxide dismutase, and glutathione peroxidase and malondialdehyde measured. The most important histological changes observed in the liver tissue were: vacuolation of hepatocytes, nuclear hypertrophy, necrosis of liver cells, expansion of sinusoids, and accumulation of fat cells. In the highest dose, the intensity of tissue changes increased. Activity of antioxidant enzymes and malondialdehyde content increased in fish exposed to 100 µg/g/week BPA in compare with other groups (p < .05). According to our findings, it could be concluded that liver histology was affected by BPA and tissue damage had occurred, which had led to changes in blood parameters. Also, the obtained results showed that the high concentrations of BPA used in this study stimulate the antioxidant defense. RESEARCH HIGHLIGHTS: BPA evoke oxidative stress in Siberian sturgeons in high dose of exposure. Severity of liver histologic lesions was dose dependent.

Maternal supplementation of nano-selenium in a plant-based diet improves antioxidant competence of female Arabian yellowfin sea bream (Acanthopagrus arabicus) breeders and their progeny.

Antioxidants such as selenium (Se) play vital roles in reproduction success and larval development in fish. A three-month feeding experiment was conducted to examine the impact of enriching a plant-based diet (60% of fishmeal was substituted with a blend of plant ingredients) with nano-selenium (nano-Se) on antioxidant metabolism in female brooders and the progeny of Arabian yellowfin sea bream (Acanthopagrus arabicus). At this point, the plant-based diet was supplemented with graded levels of nano-Se at 0, 0.5, 1, 2, and 4 mg/Kg diet. Moreover, a fishmeal-based diet served as a positive control (FMD-Control). Broodfish were randomly distributed into eighteen 10 m3 rectangular concrete tanks (8 males and 8 females in each tank). Each experimental diet was subjected to three replications. Selenium retention increased in the serum, liver, ovary, eggs, and three-day larvae with increasing dietary nano-Se levels (P < 0.05). Supplementing the plant-based diet with 2-4 mg nano-Se/Kg significantly enhanced normal embryogenesis, fertilization, hatching, and larval survival rates. Generally, fish fed on plant-based diets with lower nano-Se supplementation (0-0.5 mg/Kg) had higher catalase and superoxide dismutase activities in the liver, ovaries, eggs, and larvae compared to the other groups. Glutathione peroxidase activity and total antioxidant capacity markedly increased, whereas lipid peroxidation decreased in the liver, ovary, serum, eggs, and progeny of broodfish fed with nano-Se supplemented diets (P < 0.05). In conclusion, supplementation of 2-4 mg nano-Se /Kg in a plan-based feed is recommended for the improvement of antioxidant defense in female A. arabicus brooders and their progeny.

The effects of bisphenol A on liver proteome and mucus vitellogenin in comparison to plasma as a non-invasive biomarker in immature Siberian sturgeons (Acipenser baerii).

This study was done to evaluate the effects of Bisphenol A (BPA) on Siberian sturgeon (Acipenser baerii). As liver is the main organ in the homeostatic adjustments to stress, we used a proteomics method to address molecular response in this tissue. Also, we compared the levels of vitellogenin in plasma and mucus to propose that the last one be a non-invasive method to analyze this biomarker. The fish received 1, 10, and 100 µg g-1 week-1 BPA intraperitoneally for two weeks. The samples were taken on days 0, 7, and 14. Plasma vitellogenin level increased as the highest value was recorded in the group with 100 µg g-1 week-1 of BPA. Changes in the mucus and blood vitellogenin showed a similar pattern, suggesting that mucus could be used for evaluating the changes in blood vitellogenin. Comparative proteomics was used to determine the proteome of the liver of A. baerii in the highest dose of BPA in comparison with the control. Sixteen proteins were identified that their expression changed at least twice between the studied groups. The proteomic results showed that BPA increased the expression of proteins involved in the detoxification and metabolism, activated glycolysis, and produced necrosis in the liver.

Synergistic Effects of Selenium and Magnesium Nanoparticles on Growth, Digestive Enzymes, Some Serum Biochemical Parameters and Immunity of Asian Sea Bass (Lates calcarifer).

This study aimed to investigate the effect of selenium and magnesium nanoparticles and their combination on growth, serum biochemical and immune parameters, serum hepatic enzymes, and digestive enzymes in Asian Sea bass (Lates calcarifer), with an average weight of 32.78 ± 1.16 g for 42 days. After 4 weeks of adaptation to experimental conditions, 96 fish were randomly distributed equally in 12 cylindrical 300-l fiberglass tanks. Four treatment groups included control, 4 mg nano-selenium (Nano-Se), 500 mg nano-magnesium (Nano-Mg), and a combined treatment of 4 mg Nano-SE + 500 mg Nano-Mg treatments examined in this study. The fish fed twice a day as satiation. The results showed fish fed with combined treatment showed the highest rate of body weight gain and the specific growth rate. Digestive enzymes were significantly different between experimental treatments (p < 0.05), whereas amylase did not show a significant difference between experimental treatments (p > 0.05). The results of this study showed that serum levels of glucose, cholesterol, triglyceride, and protein indices did not show any significant difference (p > 0.05). The immunoglobulin, IgM, C3, and ACH50 indexes did not differ significantly between the experimental treatments (p > 0.05). But cortisol and lysozyme were significantly different between the experimental treatments (p < 0.05). Serum levels of SGPT, SGOT, ALP, and LDH decreased in comparison with the control group (p < 0.05). The results of the present study showed that adding Nano-Se and Nano-Mg to the diet of L. calcarifer had a positive effect on the growth and non-specific immune system with no disturbance in serum biochemical and hepatic enzymes parameters.

The effect of Pediococcus acidilactici on mucosal immune responses, growth, and reproductive performance in zebrafish (Danio rerio).

A completely randomized experimental design carried out to investigate the effects of different levels of Pediococcus acidilactici (PA) including 0 (basal diet as a control diet), 1 × 106, 2 × 106, 4 × 106, and 8 × 106 colony-forming unit (CFU) per gram of the diet for 60 days on the mucosal immunity responses, growth, and reproductive performance, in zebrafish, Danio rerio (with mean weigh ± SE: 120 ± 10 mg). The obtained results revealed that the best growth and reproduction indices were related to the concentration of 4 × 106 CFU PA g-1 diet (P < 0.05). The maximum activities of mucosal immune responses including total protein, alternative complement system, IgM, and lysozyme were observed in the fish fed with 4 × 106 CFU PA g-1 diet (P < 0.05). Furthermore, the maximum alkaline phosphatase activity of skin mucus was recorded in the fish fed with 8 × 106 CFU PA g-1 diet (P < 0.05). Fish fed with 4 × 106 CFU PA g-1 diet had the highest villus length and width of the intestine (P < 0.05). Supplementing the diet with 4 × 106 CFU PA g-1 diet more significantly enhanced Cyp19a gene expression in comparison with this in other groups. Hence, PA with a concentration of 4 × 106 CFU g-1 diet can be considered as a proper level of probiotic for improving the health, growth, and reproductive performance of the D. rerio.

Comparative toxicity of nanoparticulate and ionic copper following dietary exposure to common carp (Cyprinus carpio).

Copper is an essential element for the normal growth and survival of all organisms including fish. However, its excessive presence in the environment can cause bioaccumulation and aquatic toxicology. The aim of the present study was to compare the dietary toxicity effects of two different Cu compounds, copper oxide nanoparticles (CuO-NPs) and ionic copper (CuSO4) in juvenile common carp, Cyprinus carpio. To prepare experimental diets, two nominal concentrations of 100 and 1000 mg Cu kg-1 diet were added to a basal diet. Carp (n = 450, average initial weight of 35.94 ± 5.35 g) were fed on the Cu-supplemented diets and basal diets for two 21-day courses as dietary exposure and recovery periods, respectively. The growth performance, survival rate and blood biochemical indices as well as copper accumulation in target organs of fish were investigated at the end of each exposure period. The results showed that the weight gain (WG) of carp significantly decreased coincident with increasing concentration of the both dietary Cu forms (P = 0.00). Both Cu sources at concentrations of 100 mg kg-1 diet decreased the survival rate of fish (P = 0.003), likely due to more feed intake and thus increased copper toxicity. The both forms of dietary Cu at two different concentrations significantly decreased the plasma glutamate oxaloacetate transaminase (GOT) level compared to the control group (P = 0.008). Fish exposed to diets containing Cu sources except 100 mg Cu kg-1 of CuO-NPs showed the lower glutamate pyruvate transaminase (GPT) activity in comparison to the control (P = 0.00). The plasma sodium level in1000 mg CuO-NPs kg-1 diet was significantly lower than the control (P = 0.001). The plasma potassium level increased in the all Cu-supplemented groups except 100 mg kg-1 of CuO-NPs after the dietary exposure period (P = 0.035). The copper accumulation was dose-dependent in all target organs. In 100 mg Cu kg-1 dietary groups, the liver showed the highest Cu accumulation (P = 0.00), while in 1000 mg Cu kg-1 dietary groups, the highest Cu content was observed in the intestine (P = 0.00). The results demonstrated the enhanced toxicological responses in fish after 21 days of dietary exposure, but the levels of most of biochemical indices and tissues Cu content decreased or returned to the control values after the recovery period.

Comparison of proteomic profiles in the ovary of Sterlet sturgeon (Acipenser ruthenus) during vitellogenic stages.

One of the challenges of sturgeon aquaculture is that sturgeon takes an extended amount of time to reach sexual maturity. The pattern of the protein expression in relation to the late maturity of sturgeon can help to better understand changes in sexual maturity. 17ß-estradiol (E2), testosterone (T) and vitellogenin (Vtg) levels were examined at all stages of sexual maturation in Sterlet sturgeon (Acipenser ruthenus). Two-dimensional gel electrophoresis and mass spectrometry analysis were used to show the pattern of the ovarian proteins. The T levels increased from the previtellogenic to the postvitellogenic stages (P < 0.05) and Vtg showed a decremental pattern in pre- and postvitellogenic, and atresia (not significantly). The analysis showed 900 protein spots, 19 of which were successfully identified and had significant differences between the previtellogenic and the vitellogenic groups (P < 0.05). Among the identified proteins, 40% involved in cell defense (heat shock protein, Glutathione peroxidase, natural killer enhancing factor, peroxiredoxin-2), 30% in transcription and translation (constitutive photomorphogenesis 9 and Ybx2), 20% in metabolism and energy production (triose-phosphate isomerase (TPI)) and 10% in transport (glycolipid transfer protein). In the vitellogenic stage, the proteins were related to metabolism and energy production (TPI, ES1, creatin kinase, enolase, nucleoside diphosphate kinase, 50%), cell defense (thioredoxin and dislophid isomerase, 20%) and transport (fatty acid binding protein, 10%). Our findings show changes in protein expression pattern from cell defense to metabolism during egg development.

Effects of dietary organic, inorganic, and nanoparticulate selenium sources on growth, hemato-immunological, and serum biochemical parameters of common carp (Cyprinus carpio).

An 8-week feeding trial was conducted to compare the effects of supplementing (0.7 mg kg-1) different dietary selenium (Se) sources including organic [selenomethionine (SeMet)], inorganic [sodium selenite (Na2SeO3)], and nanoparticulate Se (nano-Se) on physiological responses of common carp, Cyprinus carpio juveniles (9.7 ± 0.1 g). Basal diet without Se supplementation used as control. Fish fed nano-Se supplemented diet had the highest weight gain (97.2 ± 10.8%) and feed efficiency ratio (42.4 ± 0.8%). Intestinal villi height was significantly taller in fish fed nano-Se diet than in the control group in both foregut and midgut sections. Serum glutathione peroxidase and superoxide dismutase activities were significantly higher in nano-Se and SeMet groups than in control and sodium selenite groups. Fish fed Se-supplemented diets had greater red blood cell counts and hematocrit and hemoglobin values than the control group (P < 0.05). Nano-Se and SeMet groups showed a significant increase in white blood cell counts, neutrophil percentage, and serum lysozyme activity than the other groups. Fish fed nano-Se diet had the highest serum hemolytic activity, total immunoglobulin, and total protein and albumin contents, as well as the lowest serum total cholesterol and low density lipoprotein levels (P < 0.05). Overall, significant improvements in growth performance, feed utilization, intestinal morphology, and hemato-immunological and serum biochemical parameters of common carp juveniles suggest nano-Se as an efficient source for providing dietary Se in this species.

Effects of chronic high stocking density on liver proteome of rainbow trout (Oncorhynchus mykiss).

The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m-3 and high stocking density (HD) = 80 kg m-3). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.

Proteomic analysis of liver tissue from rainbow trout (Oncorhynchus mykiss) under high rearing density after administration of dietary vitamin E and selenium nanoparticles.

The aim of the present study was to investigate the effects of dietary vitamin E (vit E) and selenium nanoparticles (nanoSe) on liver proteome profile of rainbow trout under high density condition. To correlate the proteome modifications with physiological aspects, growth, serum metabolites (cortisol, glucose, lactate, ALT, AST, and ALP), and liver antioxidant-related parameters (SOD, GPx, CAT, and MDA) were also examined. A total of 1275 fish (average weight of 42.6±2.3g) were stocked into 12 tanks at a density of 80kgm-3. The fish were divided into four groups according to diet: control (basal diet), vit E (500mgkg-1 vit E-supplemented diet), nanoSe (1mgkg-1 nanoSe-supplemented diet), and combination (500mgkg-1 vit E and 1mgkg-1 nanoSe-supplemented diet). After 60days, the best performance and health status of fish were observed in vit E and combination groups. Supplementation with nanoSe had no significant effects on growth performance. In addition, we compared liver proteome profiles of fish fed with a basal diet (control) and diets supplemented with vit E or nanoSe. Among the identified proteins, GRP78, ATPsyn-d, and HSP70 had an increased abundance in the vit E group, while HPPD and GAPDH showed a decreased abundance. In response to nanoSe supplementation, the expression of MDH, FAA, FBPA, TPI, GRHPR, GNMT, FDH, and Enol was increased. The proteomic data indicate that vit E or nanoSe supplementation can alter the expression of proteins involved in metabolic status of rainbow trout reared under high rearing density.

Modifications in the proteome of rainbow trout (Oncorhynchus mykiss) embryo and fry as an effect of triploidy induction.

Two-dimensional gel electrophoresis (2-DE), matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry, and database searching were used to analyze the effects of triploidization heat shock treatment on protein expression in rainbow trout eyed embryo and fry. After fertilization, the eggs were incubated at 10 °C for 10 min. Half of the eggs were then subjected to heat shock for 10 min submerged in a 28 °C water bath to induce triploidy. The remainder was incubated normally and used as diploid controls. Specimens of eyed embryos and fry were taken on 18 and 76 days post-fertilization, respectively. In the eyed embryo extracts, seven protein spots were significantly changed in abundance between the control and heat-shocked groups and one of these was decreased while the others were increased in the heat shock-treated group. Of the spots that were shown to change in abundance in the eyed embryos with heat shock treatment, two were identified as vitellogenin, while the others were creatine kinase and angiotensin I. In the 2-DE from the fry muscle extraction, 23 spots were significantly changed in abundance between the diploid and triploid groups. Nineteen of these showed a decreased abundance in diploids, while the remaining four spots had an increased abundance. Triploidization caused differential expression of muscle metabolic proteins including triosephosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, and beta-enolase. Myosin heavy chain as a structural protein was also found to change in abundance in triploids. The altered expression of both structural and metabolic proteins in triploids was consistent with their increased cell size and lower growth performance.

Effects of tetraploidy induction on rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) proteome at early stages of development.

The aim of the present study was to examine the effects of tetraploidy induction on proteome of rainbow trout during the early stages of development. After insemination, the eggs were incubated at 10°C for 350min. Thereafter, half of the eggs were exposed to a heat-shock of 28°C for 10min. The remainder were incubated normally and used as diploid controls. Fertilized egg specimens were selected 390min post-fertilization. Samples corresponding respectively to eyed embryos and fry stages were also taken on days 18 and 76 post-fertilization. Based on two-dimensional electrophoresis, all spots that were found to differ significantly in abundance between the untreated and heat-shock treated groups were selected for identification using MALDI-TOF/TOF mass spectrometry. Out of 19 protein spots showing altered abundance in the present study, 13 spots were successfully identified. Of the spots that were shown to change in abundance in the fertilized eggs with heat-shock treatment, three were identified as vitellogenin (spots 1, 2 and 3); while the others were creatine kinase (spot 5) and nucleoside diphosphate kinase (spot 6). All of the proteins identified in the embryos were related to vitellogenin (spots 8, 12 and 13). Among the identified spots from the fry muscle extracts, two were identified as beta-globin (spots 14 and 17); while the others were parvalbumin (spots 15 and 16) and creatine kinase (spot 19). The results obtained in our study may now set the ground for investigations on gene regulation and proteome modifications in polyploid fish.

Effects of triploidy induction on antioxidant defense status in rainbow trout (Oncorhynchus mykiss) during early development.

The objective of the present study was to examine the antioxidant status of rainbow trout (Oncorhynchus mykiss) during the early stages of development (fertilized egg, eyed egg, alevin and fry) as an effect of triploidy induction. Eggs and milt were taken from eight females and six males. After insemination, the eggs were incubated at 10°C for 10min. Half of the fertilized eggs were then subjected to heat-shock for 10min submerged in a 28°C water bath to induce triploidy. The remainder were incubated normally and used as diploid controls. Three batches of eggs were randomly selected from each group (control and heat-shocked) and were incubated at 10-11°C under the same environmental conditions in hatchery troughs until the fry stage. Triplicate samples of fertilized eggs from each experimental group were randomly selected 1.5h post-fertilization and at the eyed egg stage of development (18 days post-fertilization, dpf). At 27 dpf, triplicate samples of alevins were chosen from each group. Based on ploidy determination experiment performed on both groups, nine diploid and nine triploid fry (76 dpf) were also selected. The triploidy induction success rate was 87.1%. Vitamin C was in lesser concentrations in fertilized eggs and eyed eggs of the heat-shock treatment group as compared with eggs of the diploid group. Alevins of the heat-shock treatment group had a lower superoxide dismutase (SOD) activity than alevins of the diploid group. Glutathione peroxidase (GPx) level was greater in fertilized eggs and alevins of the heat-shock treatment group as compared to diploids. Catalse (CAT) activity was greater in fertilized eggs, alevins and fry of the heat-shock treatment group than those of the diploid group. Malondialdehyde (MDA), as an index of lipid peroxidation, was in greater concentration in fertilized eggs of the group that was heat-shocked, but it was lesser in alevins and fry of the group in which the eggs were heat-shocked as compared to diploid counterparts. The results demonstrate that heat-shock treatment leads to changes in the values of antioxidant enzymes such as SOD, CAT and GPx, and low molecular weight free-radical scavengers such as vitamin C, as well as level of lipid peroxidation.

Proteomic analysis of skeletal deformity in diploid and triploid rainbow trout (Oncorhynchus mykiss) larvae.

A proteomic screening approach was employed to achieve a better understanding of the changes that occur in protein expression patterns associated with skeletal deformities in both diploid and triploid rainbow trout larvae. Triploidy was induced through the application of heat shock of 28°C for 10min to eggs 10-min post fertilization in an aquarium equipped with a heater. Percentage of skeletal deformity in heat-shocked larvae (2.88±0.30, mean±S.E.) was significantly (P<0.05) greater than that of the diploids (0.55±0.24). At five days after hatching, proteins of normal and deformed specimens of deyolked larvae were subjected to proteomic analysis using two-dimensional electrophoresis and mass spectrometry. Among the identified protein spots from diploids, creatine kinase was found to be increased in larvae with skeletal deformities, while apolipoprotein A-I-2, apolipoprotein A-II and calmodulin were found to be decreased in deformed fish. Among the five protein spots that were identified in heat-shocked fish, apolipoprotein A-I-2, apolipoprotein A-II, parvalbumin, myosin light chain 1-1 and nucleoside diphosphate kinase were found to be decreased in deformed larvae. The identification of nine protein spots showing altered expression in deformed fish allows us to reach a preliminary view of the molecular mechanisms that are involved in the development of skeletal malformations in diploid and triploid fish.

Proteome changes in rainbow trout (Oncorhynchus mykiss) fertilized eggs as an effect of triploidization heat-shock treatment.

The aim of the present study was to explore proteome changes in rainbow trout (Oncorhynchus mykiss) fertilized eggs as an effect of triploidization heat-shock treatment. Eggs and milt were taken from eight females and six males. The gametes were pooled to minimize the individual differences. After insemination, the eggs were incubated at 10°C for 10min. Half of the fertilized eggs were then subjected to heat shock for 10min submerged in a 28°C water bath to induce triploidy. The remainder were incubated normally and used as diploid controls. Three batches of eggs were randomly selected from each group and were incubated at 10-11°C under the same environmental conditions in hatchery troughs until the fry stage. Triplicate samples of 30 eggs (10 eggs per trough) from each group were randomly selected 1.5h post-fertilization for proteome extraction. Egg proteins were analyzed using two-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF mass spectrometry. Based on the results from the statistical analyses, 15 protein spots were found to decrease significantly in abundance in heat-shock treated group and were selected for identification. Out of 15 protein spots showing altered abundance, 14 spots were successfully identified. All of the egg proteins identified in our study were related to vitellogenin (vtg). Decreased abundance of vitellogenin in heat-shock treated eggs in our study may either be explained by (i) higher utilization of vtg as an effect of increased cell size in triploids or (ii) changed metabolism in response to heat-shock stress and (iii) diffusion of vtg through chorion due to incidence of egg shell damage. Decreased abundance of vitellogenin in heat-shock treated eggs was associated with reduced early survival rates and lowered growth performance of triploid fish.

Effects of triploidy induction on physiological and immunological characteristics of rainbow trout (Oncorhynchus mykiss) at early developmental stages (fertilized eggs, eyed eggs and fry).

The aim of this study was to compare effects of triploidy induction on basal physiological and immunological characteristics in rainbow trout at three developmental stages including fertilized eggs, eyed eggs and fry. Eggs and milt were taken from eight females and six males. The gametes were pooled to minimize the individual differences. After insemination, the eggs were incubated at 10°C for 10min. Half of the fertilized eggs were then subjected to heat shock for 10min submerged in a 28°C water bath to induce triploidy. The remainder were incubated normally and used as diploid controls. Three batches of eggs were randomly selected from each group and were incubated at 10-11°C under the same environmental conditions in hatchery troughs until the fry stage. The first-feeding offspring were also reared under the same environmental and nutritional conditions for 38 days. Triplicate samples of 30 eggs (10 eggs per trough) from each group were selected 1.5h post-fertilization and at the eyed stage. Based on red blood cell analysis, nine diploid and nine triploid fish were also selected for study. The triploidy induction success rate was 87.1%. While diploid fish had greater body weights than those in the heat-shock treatment group, weight gain (WG%) was not different between the fry of the diploid and heat-shock treatment groups. Of thyroid hormones measured, 3,5,3'-triiodo-l-thyronine (T3) was less (P<0.05) in eyed eggs of the heat-shock treatment group, but thyroxine (T4) was greater in fry of the heat-shock treatment group as compared to those that were diploid. Cortisol concentration was greater in fry of the heat-shock treatment group as compared to those that were diploid suggesting that fry in the triploid state may be more susceptible to stressors. Concentrations of immune variables (lysozyme, ACH50, albumin, IgM, total protein, globulin and complement) were either comparable or greater in fry of the heat-shock treatment group suggesting that the immune system is not impaired in fish as a result of triploidy induction.

Effect of dietary aloe vera on growth and lipid peroxidation indices in rainbow trout (Oncorhynchus mykiss).

Aloe vera has been used worldwide in pharmaceutical, food and cosmetic industries due to the plethora of biological activities of its constituents. This study was done to evaluate the effects of dietary aloe vera on growth and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). A total number of 480 O. mykiss (mean weight 9.50 ± 0.85 g) were randomized into four experimental groups including one control and three experimental groups that aloe vera was incorporated in their diet at 0.5, 1.0 and 2.0 g kg(-1). Trial was done for eight weeks. Then biometry and blood sampling were done. Plasma malondialdehyde, ferric reducing ability of plasma and growth index were estimated at the end of study. The results showed that aloe vera extract did not affect growth indices. Malondialdehyde was increased in the experimental group compared to the control group but ferric reducing ability of plasma showed a decrease in experimental groups (p < 0.05) compared to the control group. Our findings showed that dietary aloe vera have adverse effects on antioxidant defense system in O. mykiss.

Effects of mannan oligosaccharide supplementation on growth, some immune responses and gut lactic acid bacteria of common carp (Cyprinus Carpio) fingerlings.

This study was conducted to determine the effects of mannan oligosaccharide (MOS) on growth, some immune responses and gut lactic acid bacteria of common carp. Four experimental diets containing 0%, 0.05%, 0.10% and 0.20% MOS were prepared. Each diet was randomly allocated to triplicate groups of fish with initial average weight of approximately 14 g. After eight weeks, survival rate was high in all treatments with no significant difference (p > 0.05). Growth performance including final weight, weight gain (WG) and specific growth rate (SGR) did not differ among the treatments. Feed conversion ratio (FCR) was better when the fish were fed 0.05 to 0.20% MOS diets. The alternative complement activity, lysozyme activity and serum total Ig were found to be significantly (p < 0.05) greater in fish fed 0.20% MOS diets. Although the total intestinal bacterial counts were not affected by dietary treatment (p > 0.05), the lactic acid bacteria levels were significantly elevated in fish fed MOS diets (p < 0.05). These results indicated that oral administration of MOS at 0.20% elevated the immune response, improved FCR and modulated intestinal microbiota of common carp.

Effects of dietary nucleotides supplementation on rainbow trout (Oncorhynchus mykiss) performance and acute stress response.

This experiment was conducted to examine the effect of dietary nucleotides (NT) on fish performance and acute stress response on fingerling rainbow trout (23 g ± 0.01, mean weight ± SEM). Five experimental diets according to different levels of supplemented nucleotides (0, 0.05, 0.1, 0.15, and 0.2%) were assayed on experimental fish for 8 weeks. Growth, hematological parameters (hematocrit, hemoglobin, erythrocyte, lymphocyte, and neutrophil count), serum proteins (globulin, albumin), and plasma enzymatic activity (alkaline phosphatase, ALP; aspartate transaminase, AST; lactate dehydrogenase, LDH; alanine transaminase, ALT) were assayed. At the end of feeding trial, fish fed the control and 0.2% diets were subjected to handling and crowding stress. Modulatory effects of nucleotides on acute stress response (cortisol and glucose) and plasma electrolytes (Na(+), Cl(-), K(+), and Ca(2+)) were studied. The percentage of body weight gain (WG) and feed efficiency (FE) of fish were better when the fish were fed 0.15-0.2% diets. Fish fed the nucleotide-supplemented diets tended to have lower levels of serum enzymes including ALP, AST, LDH, and ALT. Plasma cortisol levels of fish fed on 0.2% diet under handling and crowding stress were significantly lower than fish fed the control diet at all post-stress time intervals. In our study, fish fed nucleotide-supplemented diet had significantly lower concentrations of glucose compared to those fed the basal diet. The concentrations of sodium, chloride, calcium, and potassium of fish fed the control diet were significantly lower than in fish fed nucleotide-supplemented diet. Dietary nucleotides administration seems to promote growth and to enhance resistance against handling and crowding stress in fingerling rainbow trout.