Journal of Aquaculture Development
Year:2013 | Volume:7 | Issue:3|Papers Count:8

The Common Carp Cyprinus carpio belongs to the Cyprinidae, the largest freshwater teleost family and is an important economic species in the Caspian Sea. In recent decades the restocking of Common Carp stocks has been conducted through artificial propagation that can change the genetic variability. Genetic diversity and population structure of Common Carp investigated in Anzali wetland and Gorganrud estuary. Total of 60 specimens of adult Common Carp were sampled from two seasons. Seven pairs of microsatellites were tested to determine at disomic loci amplified from fin tissue samples. In this study, only five primer pairs were used successfully. The average of alleles per locus was 9.5 (range 7 to 12 alleles per locus in regions). All sampled regions contained private alleles. Average observed and expected heterozygosity were 0. 81 and 0.849 respectively. In all cases, significant deviations from Hardy-Weinberg (HW) equilibrium were observed (P<0.01) except in one locus (Syp4) where was HW equilibrium in Anzali wetland samples. Basis on AMOVA for both Fst and Rst values among them indicated a significant difference between the populations (P<0.01). The genetic distance between populations which indicates that the genetic difference among the studied populations is pronounced. These results support the existence of at least two genetic distinct populations in Anzali Wetland and Gorganrud estuary.

This study was conducted to compare biotic (abunance and biomass of phytoplankton and zooplankton) and abiotic (physico-chemical) parameters in three warm water fish ponds fertilized with: 1- Chemical fertilizer, 2- Combined of chemical and organic (Cow manure) fertilizer 3- Organic fertilizer (Cow manure) in Mazandaran province. Results in current study showed that dissolved oxygen content was not lower than of standard levels of warm water fish ponds and pH was alkaline (7.57±0.17 with a range of 7.54-8.94) that was in the range of standard level. The concentrations of amonia, nitrate and phosphate were desirable. Results also showed that abundance phytoplankton in pond 2 (fertilized with combine of chemical and organic fertilizers) increased more than other ponds. Total zooplankton biomass and its main groups (Rotifera, Coppepoda and Cladocera) showed the highest value in the pond with both chemical and organic fertilizers. As a conclusion, it seems that use of manure as organic fertilizer associated with chemical fertilizer has more potential to produce biotic foods for warm water fish. In addition, this approach reduces the cost to farmers for the purchase of chemical fertilizers.

The purpose of this study is the diagnosis of white fish Rutilus frisii kutum by detecting variations in serum proteins transferrin and esterase enzyme in Shiroud and Tajan rivers in the spring and fall. For this purpose, 60 pcs fish in each river and 148 pcs white fish in the sea, near the mouth of each of these streams were collected. Qualitative and quantitative studies of transferrin in the spring of these fish showed a significant difference (p<0.05), whereas samples did not reveal significant differences in autumn. As well as this study, transferrin protein in with fish of Caspian Sea had aa, ab and bb genotypes and estrase had aa and bb genotypes. Morphometric analyzes of samples collected in significant differences between the two populations of Shiroud and Tajan rivers in the spring, but did not show significant differences in autumn.

In aquaculture, transporting fish from one location to another is inevitable. The major problems encountered in fish transportation are control of metabolic wastes and supply of dissolved oxygen. Anesthetics are used with increasing frequency in aquaculture, mainly to reduce the stress and to prevent mechanical damage to fish during handling and transportation. Simulated transportation of Oncorhynchus mykiss fingerlings was carried out to study the effects of lidocaine-hydrochloride on water parameters. Dissolved oxygen, ammonia nitrogen and pH of control group and lidocaine hydrochloride treated group of 5ppm, 10ppm, 20ppm lidocaine-hydrochloride ware tested at 1h, 2h, 3h, 4h and 5h treatment duration. Lidocaine-hydrochloride treated group, followed by control group, were most effective in decreasing oxygen consumption and excretion of ammonia by fish. Lidocaine hydrochloride dose related decrease in oxygen and excretion of ammonia were also established. pH declines in control group were more rapid compared to lidocaine-hydrochloride groups. The results of this study reveal that lidocaine-hydrochloride is an effective sedative as a transportation mixture for rainbow trout.

The aim of current study is evaluating effects of different levels of Biomin® IMBO synbiotic including Enterococcus faecium (as probiotic), and Fructo-oligosaccharides (as prebiotic) combination, on growth, survival, and gut bacterial flora of Common Carp fish (Cyprinus carpio). The experiment has been carried out in four treatment (each with 3 replicate), including 0.5, 1 and 1.5 gram synbiotic per kg diet, and control with non-synbiotic diet. Fish with average weight of 10±2 g distributed in 12 tank (25 ind/300 lit tank), fed experimental diet during 75 days. The fish were fed 60 days with above diet and then all treatments received non-supplementary (control) diet for 15 days. The results showed that the combination of probiotic and prebiotic could significantly enhance growth parameters (WG, LT, SGR and PWG) (p<0.05), but did not exhibit difference in survival (p>0.05) comparing to control. Level of 1.5 gr pro & prebiotic per kg diet exhibited best growth parameters increases within all treatments. Combination of Enterococcus faecium (as probiotic), and Fructo-oligosaccharides (as prebiotic) could change gut bacterial flora of fish (p<0.05), that stimulated lactobacillus bacteria levels and significantly enhanced Enterococcus spp. as dominant gut bacterial flora of common carp. In this study three treatments fed with probiotic and prebiotic diet showed significant difference comparing to control group (p<0.05) that level of 1.5 gr/kg diet demonstrated most gut probiotic replacement, but bacteria colony counts decreased in day 75 by probiotic elimination in diet after day 60.

Viral nervous necrosis (VNN) is a serious viral disease of fin fish caused by a Betanodavirus. In the present study, Betanodavirus was identified in apparently healthy 50-100 grams Golden Grey Mullets (Liza auratus) obtained from fish market using histopathological examination and indirect fluorescent antibody test. Histopathology studies characterized extensive vacoulation in optic nerve (%16.6), outer molecular and granular layers of the brain (%25) and inner and outer nuclear layers of retina (%5) of the investigated fish. Indirect fluorescent antibody test showed positive reaction in the same organs. The results showed at least 20 percent infected fish among investigated samples without clinical sign. So a part of apparently healthy fish supply for human consumption is infected by viral nervous necrosis.

The present study aimed to investigate the effect of thiamine on growth and thiamine deficiency signs in Rainbow Trout (Oncorhynchus mykiss). A total of 120 brood fish (1014±13.6 g) were divided into four treatments with triplicate groups in 12 tanks with a volume of 1.26 m3 (10 fish per tank). Three treatments fed diets contained 0 (T0), 1 (T1) and 10 (T10) mg thiamine hydrochloride/kg diet, respectively and other treatment (amp) fed diet contained 1 g/kg amprolium hydrochloride (as an antithiamine) for 30 days. At the end of the experiment, fish were weighed and growth parameters such as weight gain, specific growth rate, body weight increase and average daily growth were determined. The results showed that all the growth indices increased significantly in fish fed T10 compared to fish fed amprolium (P<0.05). After 30 day, some thiamine deficiency sings included decreased appetite, weak growth, hysteria, rally in tank corner and surface water, jaw and fin erosions especially in caudal fin were observed in fish fed amprolium, and T0 and T1 compared the T10. The results revealed that thiamine is an essential nutrient for growth and deficiency sings occurs quickly in fish.

In this study, the levels of testosterone and gonadotropin hormone II (GTHII) were measured by radioimmunoassay method before and after ovulation. This experiment was conducted to determine the optimum levels of LHRHA2 of protein levels on the quantity and quality of egg and larvae of Persian Sturgeon (Acipenser persicus) bloodstock. Results showed that the mean plasma testosterone levels in female bloodstocks in treatments 4, 6 and 8mg/kg were 24.88±7.11, 14.8±1.77 and 22.56±7.74; 9.57±3.37, 6.2±2.23, 6.69±2.17ng/ml, respectively. GTHII levels were 2.12±0.54, 1.96±0.72 and 0.94±0.25; 0.91±0.20, 0.70±0.13 and 0.66 ± 0.17 ng/ml, respectively. Testosterone levels  showed significant difference in all treatments but GTHII levels showed significant difference at treatments 4 and 6 mg/ kg before and after injection (P<0.05). GTHII levels at concentration 8 mg/kg showed no significant difference (P>0.05). The results showed that ovulation in treatment 4mg/kg (100%) were more than the other treatments (67%). According to the results, it can be said that the most suitable concentration of LHRHA2 hormone was equal to 4 mg/kg in female Persian sturgeon (Acipenser persicus) brood stock for artificial propagation and efficiency improvement.