Minimally invasive surgical technique for egg collection from the Persian sturgeon, Acipenser persicus

A minimally invasive surgical technique (MIST) for the removal of ovulated eggs from Persian sturgeon Acipenser persicus was tested on broodstocks caught from the wild to determine whether it affected fecundity or hatching rates compared with the traditional stripping method of killing and removing the eggs (commonly used in hatchery). Morphological parameters of females, germinal vesicle (GV) position, weight of obtained egg, number of eggs/gram, fertilization rate, and percentage of hatching during incubation were not significantly different between the MIST and traditional stripping methods. Obtained ova were 4.8 ± 0.4 kg female⁻¹ in the MIST and 4.6 ± 0.5 kg female⁻¹ in traditional stripped groups, respectively; the fertilization rate was 83.4 ± 11.2% and 80.0 ± 7.2% in groups, respectively. The results of this study showed that the minimally invasive surgical technique approach is efficient, practical, and less stressful to Persian sturgeon broodstocks during artificial propagation than other reported egg collection procedures.     

Effects of dietary inorganic copper on growth performance and immune responses of juvenile beluga,Huso huso

A 12‐week feeding trial was conducted to evaluate the optimum dietary inorganic copper (copper sulphate) in juvenile beluga, Huso huso. Eight semi‐purified diets containing 1.1 (Cu_1.0), 3.5 (Cu_4.0), 7.1 (Cu_7.0), 9.7 (Cu₁₀), 13.1 (Cu₁₃), 25.1 (Cu₂₅), 49.9 (Cu₅₀) and 195 (Cu₁₉₅) mg Cu kg^?1 diet in the form of CuSO₄.5H₂O were fed to fish of initial body weight 8.49 ± 0.32 g and length 11.85 ± 0.66 cm (mean ± SD) in triplicate groups in a flow‐through system. Weight gain (WG) of fish fed Cu₁₀ and Cu₁₃ diets was significantly higher than that of fish fed Cu_1.0, Cu_4.0, Cu₂₅, Cu₅₀ and Cu₁₉₅ diets (P < 0.05). Whole‐body and muscle crude protein increased with dietary Cu up to the supplementation level of 13.1 mg kg^?1 diet and then decreased. Whole‐body lipid content was negatively correlated, while whole‐body ash was positively correlated with dietary copper concentration. Hepatic copper–zinc superoxide dismutase activity of fish fed Cu₁₀ and Cu₁₃ diets was significantly higher than that of fish fed Cu_1.0, Cu_4.0 and Cu₁₉₅ diets. Hepatic thiobarbituric acid‐reactive substances of fish fed Cu₁₃ diet was significantly lower than those of fish fed the other diets except for that of fish fed Cu₁₀ diet. Aspartate aminotransferase, alanine aminotransferase and copper accumulation in tissues increased with dietary copper. Broken‐line analysis of WG suggested that the optimum dietary Cu level was 10.3 mg Cu kg^?1 diet. Therefore, these results may indicate that the optimum dietary Cu levels could be greater than 10.3 mg Cu kg^?1 diet but less than 13.1 mg Cu kg^?1 diet in juvenile beluga, when copper sulphate is used as the dietary source of inorganic copper.     

Effect of dietary soybean meal and multienzyme on intestine histology of beluga sturgeon (Huso huso)

International Aquatic Research - This study aimed to evaluate the effect of soybean meal and multienzyme supplementation on intestinal histopathology of beluga sturgeon (Huso huso). Nine diets were...     

The effects of oligofructose on growth performance,survival and autochthonous intestinal microbiota of beluga (Huso huso) juveniles

Preliminary experiments were undertaken to investigate the effects of oligofructose on beluga sturgeon (Huso huso) growth performance, survival and culturable autochthonous intestinal microbiota. Juveniles (20 g) were fed diets containing varying levels of oligofructose (10, 20 and 30 g kg^?1) at 2–3% body weight per day for 7 weeks. Compared to the control group, no significant (P > 0.05) effect on growth performance was observed in fish fed diets supplemented with oligofructose at 10 and 20 g kg^?1. However, compared to the 20 g kg^?1 group, feeding oligofructose at 30 g kg^?1 resulted in adverse effects on growth performance. Dietary supplementation of oligofructose at 20 g kg^?1 significantly increased survival rate. Microbiological assessment indicated that the viable culturable autochthonous levels were not affected by dietary oligofructose. Although lactic acid bacteria (LAB) were not a dominant component of the endogenous autochthonous microbiota, LAB levels were significantly elevated in fish fed 20 g kg^?1 dietary oligofructose. This elevated LAB population was able to persist for at least 1 week after reverting the prebiotic group back to a control diet. This study encourages further research on different aspects of oligofructose in sturgeon culture with clear emphasis on optimizing dosage levels.     

Evaluation of the optimum dietary protein level for the maximum growth of juvenile beluga (Huso huso L.1758)

A 10‐week feeding trial was carried out to evaluate the optimum dietary protein level for the maximum growth of juvenile beluga, Huso huso. Fish averaging 1.34 ± 0.07 g (mean ± SD) was randomly distributed into 18 circular fibreglass tanks of 500 L capacity (20 fish per tank). Six iso‐caloric diets were formulated to contain 30 (CP₃₀), 35 (CP₃₅), 40 (CP₄₀), 45 (CP₄₅), 50 (CP₅₀) and 55% (CP₅₅) crude protein (CP). Fish were fed each of the six experimental diets in triplicate groups. At the end of feeding trial, weight gain (WG) and specific growth rate (SGR) in fish fed CP₄₀ and CP₄₅ diets were significantly higher than those of fish fed CP₃₀, CP₃₅, CP₅₀ and CP₅₅ diets (P < 0.05). Lipid retention increased significantly from 24.7% to 31.6%, but protein retention decreased from 54.6% to 35.6% with increasing protein levels from 30% to 50%. Muscle total essential and non‐essential amino acid (EAA & NEAA) concentrations increased with the dietary protein level up to CP₄₅ diets. Muscle total EAA concentrations (%) of fish fed CP₄₅ were significantly higher than those of fish fed CP₃₀, CP₃₅, CP₅₀ and CP₅₅, but there was no significantly different between those of fish fed CP₄₀ and CP₄₅. Muscle total NEAA concentration (%) of fish fed CP₄₅ were significantly higher than those of fish fed CP₃₀ and CP₃₅ diets. Broken‐line analysis of WG suggested that the optimum dietary protein level could be 38.9% for maximum growth performance in juvenile beluga (1.3–77 g).     

Effects of levamisole,echinacea, and thyme oral administration on growth factors,blood parameters,and immunity in beluga,Huso huso

A total of 180 fish (95.50 g) were fed with 0.1% levamisole, 0.5% thyme, and 0.5% echinacea crude extract for 60 days. The control group received no stimulant. The results of growth parameters indicated a significant positive effect of levamisole in comparison with the control group, though it was not significantly different from echinacea and thyme treatments (P > 0.05). No mortalities were observed in the treatments. Feed conversion ratio and protein efficiency ratio did not differ significantly between the treatments. The highest numbers of white and red blood cells and the greatest amounts of hemoglobin and hematocrit were detected in the levamisole treatment, showing significant differences with the other groups in the percentage of hemoglobin only (P < 0.05). The highest levels of MCH and MCHC were also measured in the levamisole treatment. Differential count of white blood cells revealed no significant differences in neutrophil and lymphocyte levels with the control. There was a significant increase in the percentage of eosinophil in the levamisole treatment alone. No significant differences were recorded in total protein, albumin, and aspartate aminotransferase and alanine aminotransferase enzymes. Levamisole treatment displayed the highest activities of glutathione peroxidase and lysozyme as well as the greatest amount of immunoglobulin. So 0.1 levamisole yielded better results in the growth, blood, and immunity parameters and can be used as a stimulant without injuring body organs.     

Comparative study of dietary soy phytoestrogens genistein and equol effects on growth parameters and ovarian development in farmed female beluga sturgeon,Huso huso

Oocyte maturation in fish is a hormonally regulated process. In the light of long-term oocyte maturation in beluga, the aim of this research was to study the estrogenic effects of different concentrations of soy dietary genistein (GE) and equol (EQ) on the growth performance and ovary development in farmed female Huso huso. Fish were fed with concentrations 0 (control), 0.2, 0.4, 0.8 and 1.6 g of EQ and GE per kg of isoproteic (CP 45 %) and isoenergetic (19.5 MJ/kg) diets during a year. Blood samples and ovary biopsies were collected from each fish seasonally. The main results of the present experimentation are that growth performance was not affected significantly both in GE and EQ (P > 0.05). EQ at concentration 0.4 g/kg had more estrogenic effects than other concentrations of EQ and GE in beluga so that 64 % of fish were matured sexually. Some reproductive indices such as oocyte diameter, testosterone (T) and 17β-estradiol (E₂) increased significantly at EQ 0.4 g/kg at the end of experiment (P < 0.05), while 17α-hydroxy progesterone level (17α-OHP) showed no significant changes at all concentrations. Biochemical indices such as calcium, phosphorous and cholesterol increased at GE concentrations, but decreased at EQ concentrations similarly at the end of experiment. There was a negative relationship between plasma phosphorous and alkaline phosphatase enzyme levels. Based on results, EQ at concentration 0.4 g/kg improved oocyte development more than the other concentrations of GE and EQ, and therefore, it can be used as an additive to diets for inducing ovary development in this species.     

Effects of dietary synbiotic on growth,survival, lactobacillus bacterial count,blood indices and immunity of beluga (Huso huso Linnaeus, 1754) juvenile

This study aimed to determine the effect of synbiotic (Biomin IMBO) as feed additive on beluga (Huso huso) juvenile with an average body weight of 26.45 ± 0.19 g. Experimental diets at which supplemented with 1.0, 2.0 and 4.0 g synbiotic per kg of feed were fed to beluga juvenile, whereas the control group was fed with no synbiotic. After the feeding trial for 8 weeks, growth performance, survival, lactobacillus bacterial count, blood indices and immunity were tested. Even though, some growth performance and feed utilization parameters including WG, SGR and FCR were improved in group fed with 2.0 g kg^?1 synbiotic; however, there were no significant differences (P > 0.05) in growth and feeding parameters between juveniles fed control and synbiotic supplementation diets. In terms of intestinal microbiota, there were no significant differences in total and lactic acid bacteria among treatments (P > 0.05). In addition, there were no significant differences of RBC counts, haematocrit, monocyte, lymphocyte, neutrophil, serum glucose and serum total protein levels between the treatment groups (P > 0.05), but group 2 and 4 g kg^?1 synbiotic showed a significant difference (P < 0.05) in WBC counts and haemoglobin, respectively. Furthermore, alternative complement activity (ACH50) and serum total immunoglobulin (Ig) were significantly increased in 2.0 g kg^?1 synbiotic fed fish (P < 0.05); however, it did not change the lysozyme activity, significantly (P > 0.05). These results indicate that synbiotic improves immunity of beluga sturgeon without detrimentally impacting the growth performance, modulates intestinal microbiota and basic haematological parameters assessed. Thus, we suggest that 2.0 g kg^?1 level of synbiotic may be used as an immunity promoter for beluga sturgeon juvenile.     

Effects of dietary L‐carnitine level on growth performance,body composition and antioxidant status in beluga (Huso huso L. 1758)

A 17‐week feeding trial was carried out to evaluate the effects of dietary L‐carnitine level in beluga, Huso huso. A total of fish averaging 1247 ± 15.6 g (mean ± SD) were randomly distributed into 18 fibreglass tanks, and each tank holding 10 fish was then randomly assigned to one of three replicates of six diets with 50, 150, 350, 650, 950 and 1250 mg L‐carnitine kg^?1 diet. At the end of 17 weeks of feeding trial, average weight gain (WG), feed efficiency (FE), protein efficiency ratio (PER) and condition factor (CF) of fish fed 350 mg kg^?1 diet were significantly (P < 0.05) higher than those of fish fed 50, 150, 950 and 1250 mg kg^?1 diets. WG, FE, PER and CF of beluga fed 650 mg kg^?1 diet were also significantly higher than those of fish fed 50, 950 and 1250 mg kg^?1 diets. Whole body and muscle protein were significantly improved by the elevation of dietary L‐carnitine level up to 350 mg kg^?1. Liver superoxide dismutase and glutathione peroxidase activities of fish fed 350 and 650 mg kg^?1 diets were significantly higher than those of fish fed 50, 950 and 1250 mg kg^?1 diets. The dietary L‐carnitine level of 350–650 mg kg^?1 diet could improve growth performance, feed utilization, protein‐sparing effects of lipid, antioxidant defence system and reproductive success. Polynomial regression of WG suggested that the optimum dietary L‐carnitine level was 480 mg kg^?1 diet. Therefore, these results may indicate that the optimum dietary L‐carnitine could be higher than 350 but <650 mg kg^?1 diet in beluga reared in intensive culture conditions.     

Soya bean‐based diets plus probiotics improve the profile of fatty acids,digestibility, intestinal microflora,growth performance and the innate immunity of beluga (Huso huso)

This study was conducted to investigate the effect of different methods of using probiotics Bacillus subtilis and Bacillus licheniformis in soya bean‐based diets on the physiology of beluga (Huso huso) (351 ± 4 g). Five experimental diets were formulated to feed beluga for 10 weeks. The results showed that there was no significant difference in weight gain between control (446 g) and 70%SBM‐SPRAY2 (409 g) treatments. Long‐chain polyunsaturated fatty acids in the muscle of beluga fed control (203.2 g/kg) and 70%SBM‐SPRAY2 (166.4 g/kg) diet did not change statistically. Blood performance as a newly introduced factor in individuals fed dietary control (64.06) and 70%SBM‐SPRAY2 (64.33) had higher value as compared with those fed dietary 70%SBM‐DIET2 (61.90) (p < 0.05). Also, total protein (1.68 g/dl) and RBC (0.74 × 10⁶/mm³) in fish fed 70%SBM were statistically lower than other treatments (p < 0.05). Lysozyme, alternative complement activity and total viable counts in beluga fed dietary probiotics were significantly higher than others. In conclusion, feeding fish with the 70%SBM‐SPRAY2 diet improved fish growth and health.     

Stress Response of Juvenile Beluga,Huso huso,to Light and Tank Colors

Effects of light and tank colors on stress response of juvenile beluga sturgeon, Huso huso, was investigated by the measurement of some sero-haematological parameters and carcass chemical analysis. The analysis was based on the responses of 64 specimens (initial weight 98.83 ± 1.42 g) reared under white, red, green, or blue light, and 48 specimens reared in white, black, or blue tanks, all for 12 weeks. Blue/green light and black tanks produced positive effects on cortisol that can be related to physiological condition and stress.     

The role of dietary L‐ascorbyl‐2‐polyphosphate on the growth and physiological functions of beluga,Huso huso (Linnaeus, 1758)

Effects of dietary ascorbic acid (AA) supplementation were carried out on growth performance and physiological indices in juvenile beluga Huso huso fed different levels of dietary L‐ascorbyl‐2‐polyphosphate as AA source consisting of 0 (control), 100, 200, 400, 800 and 1600 mg AA kg^?1 diet for 16 weeks. No significant differences were found in growth performances between treated groups except for condition factor. Using AA caused significant differences in haemoglobin, number of red blood cells, white blood cells, aspartate aminotranspherase and lactate dehydrogenase, while no significant difference was found in haematocrit, mean corpuscular haemoglobin concentration, differential white blood cells count and alkaline phosphatase activity at the end of the experiment. Lysozyme activity after 8 weeks was significantly affected by dietary treatments with the lowest value in fish fed control diet, but not at completion of 16‐week feeding trial. Liver AA concentration showed a significant increase in correlation with dietary AA increase. Air exposure stress test showed significant differences among the treatments in case of cortisol and glucose concentrations. Also between pre‐ and post stress, significant changes were observed in some of treatments. The lowest and highest levels of cortisol were 9.2 ± 3 (in 200 mg kg^?1) and 16.8 ± 5.1 ng mL^?1 (in control), 6 h post stress (P < 0.05) respectively. Also, the lowest and highest levels of glucose were measured in fish fed 200 and 800 mg AA kg^?1 respectively. The obtained results showed that most growth parameters were not affected by dietary AA, but some physiological and immunological parameters of this species were influenced by this vitamin. We suggest that under rearing conditions, AA should be added to the diet especially during early life stages for improving health status and resistance to stressors.     

Growth performance,muscle and liver composition,blood traits,digestibility and gut bacteria of beluga (Huso huso) juvenile fed different levels of soybean meal and lactic acid

The objective of this study was to assess the effects of fishmeal (FM) replacement with 0, 350 or 700 g/kg soybean meal (SBM) in combination with the supplementation of lactic acid (LA; 0, 10 or 20 g/kg) in the diets of juvenile beluga sturgeon (Huso huso; 700 ± 30 g). Nine isonitrogenous (400 g/kg protein) and isoenergetic (18 MJ/kg) diets were fed to beluga ad libitum, three times a day, for 60 days. The results showed that replacing FM with SBM without LA significantly reduced fish growth; on the other hand, LA supplementation had positive effects on fish fed diets that FM was replaced by SBM (p < .05). Increasing SBM in the diet altered the fatty acid profiles of the fish, reducing long‐chain polyunsaturated fatty acids and the n‐3/n‐6 fatty acids. High amounts of SBM (700 g/kg) caused reductions in the haematocrit, glucose and cholesterol levels in the blood (p < .05). In addition, the digestibility of protein, fat, dry matter and phosphorus was reduced when replacing FM with SBM, however, adding LA to the diets increased fish performance (p < .05), and this improvement was sharper in 2% LA groups. The number of LA bacteria increased significantly with the dietary supplementation of LA (p < .05). Based on these results, replacing 350 g/kg of FM with SBM and adding 20 g/kg LA to their feed do not negatively affect the biological and physiological indices of beluga.     

The effect of lactic acid bacteria administration on growth,digestive enzyme activity and gut microbiota in Persian sturgeon (Acipenser persicus) and beluga (Huso huso) fry

The aims of this study was to assess the effect of two lactic acid bacteria (LAB), Lactobacillus curvatus and Leuconostoc mesenteroides, originally isolated from gastrointestinal (GI) tract of beluga (Huso huso) and Persian sturgeon (Acipenser persicus), respectively, on growth, survival and digestive enzyme (amylase, lipase and protease) activities and the population level of LAB in the GI tract. The treatments included 10 different groups; control, separate supplements of L. curvatus and Leu. mesenteroides at three different counts [2 × 10⁹, 5 × 10⁹ and 9 × 10⁹ colony forming units (CFU) per gram food] and three combinations of the two LAB (2 × 10⁹ + 2 × 10⁹, 5 × 10⁹ + 5 × 10⁹ and 9 × 10⁹ + 9 × 10⁹ CFU per gram food). The bacteria used in this study were added in lyophilized form to chopped Chironomidae. In the beluga study, highest specific growth rate, survival and improved intestinal enzyme activities were noted in the rearing group fed 9 × 10⁹ L. curvatus per gram food. In Persian sturgeon, the inclusion level of 2 × 10⁹ Leu. mesenteroides had similar positive effect. The ability of LAB to colonize the digestive tract seems to involve host specificity, and our bacteriological results are relevant to initiate future probiotic studies in sturgeons and future directions will be discussed.     

Fine tuning of feeding practices for hatchery produced Persian sturgeon,Acipenser persicus and Beluga sturgeon,Huso huso

In this work, we investigated the effects of various feeding treatments on the survival and growth of Huso huso and Acipenser persicus larvae during a 20‐day culture period. Three replicate groups (250 fish/replicate) of first‐feeding larvae were fed according to four main feeding regimes: (1) live food (live nauplii of brine shrimp Artemia urmiana); (2) indirect transition (5–7 days live food followed by gradual transition to formulated diet); (3) direct transition (using different combinations of live and formulated diet from the start feeding onwards); and (4) formulated feed (FD) from the start of feeding. In H. huso larvae, combining live food and manufactured diets (co‐feeding) from the first feeding stage onwards (direct transition) resulted in significantly higher weight gain than the other regimes. Survival was significantly higher in H. huso larvae fed solely live food or the direct transition regimes compared with indirect transition and FD. In A. persicus larvae, growth and survival were higher in the indirect transition feeding regime than in the other regimes. On the basis of the results of this study, we recommend co‐feeding of H. huso immediately from the commencement of exogenous feeding, but co‐feeding of A. persicus should start 7 days after prior feeding with live food.     

Effects of Feeding Time on Growth,Survival, and Food Conversion Ratio of Huso huso Fingerlings

This study was carried out to determine the effect of feeding time on growth parameters, food conversion ratio, and survival rate of Huso huso fingerlings (2.11 ± 0.03 g) over a period of five weeks. Fish in triplicate tanks were fed a commercial pelleted diet four times every 24 h on one of four schedules: at 08:00, 11:00, 14:00, and 17:00 h (day feeding); at 08:00, 12:00, 18:00, and 22:00 h (day/night feeding); at 18:00, 21:00, 24:00, and 06:00 h (night feeding); or at 08:00, 12:00, 18:00, and 22:00 h (full dark feeding). At the end of the experimental period, fish in the day-fed group had significantly (P < 0.05) better final weight, daily growth rate, specific growth rate, survival, condition factor, and food conversion ratio than day/night and night-fed groups. Performance of fish fed under full dark conditions was intermediate between day-fed and the other groups. In terms of rearing costs, daytime feeding of Huso huso is the most efficient.     

Correction to: The effect of a phytogenic feed additive (Digestrom P.E.P) on growth performance,proximate composition,hematological and immunological indices of juvenile beluga sturgeon Huso huso

Aquaculture International -     

Effects of different photoperiods on growth, stress and haematological parameters in juvenile great sturgeon Huso huso

The effects of constant light (24L:00D), no light (00L:24D) and two light–dark periods (18L:06D;12L:12D) on the growth, stress and haematological variables were assessed in juvenile great sturgeon, Huso huso . During the 8-week experimental period, juveniles (22.5 ± 0.6 g) were kept under a 150 lx light intensity in fibreglass tanks (0.8 m², 500 L). Differences in growth were insignificant during the experiment, but lactate levels were higher in the 00L:24D and 24L:00D photoperiods compared with 12L:12D and 18L:06D photoperiods. Cortisol levels did not show differences among the various photoperiods. At the end of the experimental period, fish reared under a 12L:12D photoperiod had higher haemoglobin values and erythrocyte numbers than in the other photoperiods, while no differences were found between groups with regard to haematocrit values or leucocyte numbers. The highest survival rate (89%) was observed in the 12L:12D period in which the levels of lactate and cortisol as stress indicators were minimal. The results indicate that various photoperiods cause different stress levels in juvenile great sturgeon and have no significant effects on growth, at least in short time periods.