Journal of Aquaculture Development
Year:2015 | Volume:8 | Issue:4|Papers Count:8

Cray fish, Astacus leptoductylus, is valuable and commercial aquatic of Caspian Sea and the rivers ending to the sea, and it has also exports value. Morphological and histological characteristics of cultured male and female gonads were studied during a reproductive cycle. Also, the effect of density on some reproductive indices was investigated. Crayfish were collected monthly during 10 month, from May to March. They were studied in three trials with density of 3, 5 and 7 number/m2. These trials were done in three replications. Gonadosomatic (GSI) index were determined and sex maturation were studied based of classical histology. For females, GSI peaked in December and for males, it peaked in July and November.7 and 6 maturation stages were recognized in female and males, respectively. There were not any significant differences between GSI of three treatments. The result shows that reproduction activity of cultured brood stocks occurred in late December. Also, sex maturation was not affected by density.

Stellate sturgeon (Acipenser stellatus) the endangered of migratory fishes in the southern part of the Caspian Sea and the natural resources of this species is decrease, but the gender situation in the Caspian Sea accurate information not available. The aims of this study were determine and distinguish the sex of the species Stellate. For this purpose, this studying and diagnosis of gonad maturation stages in Stellate sturgeon that were caught using trawl samples were collected during 2002-2012. Samples were fixed in Bouin's solution and studied in the laboratory according conventional histological methods (dehydration, clearing, molding and stained with H & E). The ranges of weight and length in studied A. stellatus were 15-6900 gr and 19.2-126 cm, respectively. Sexually, from a total of 138 samples, the number of males and females were 63 and 75, respectively. The number of females that were at stages I, I-II, II, II-III, III and IV were 31, 7, 25, 6, 5 and 1, respectively. The number of males that were at stage I, I-II, II, III and IV were 25, 10, 26, 1 and 1, respectively. According to results, the sexual maturation stages and biometry, the population of stellate Caspian Sea species, is very young.

In this study, the effect of high unsaturated fatty acid, levels of vitamin C and duration of enrichment on biochemical contents of Artemia urmiana nauplii were investigated. Artemia cysts were hatched in standard condition and enriched with a commercial emulsion and an inland fish oil accomplish with three levels of vitamin C during two periods, then maintained in -80 C till measured the vitamin c and fatty acids profiles of harvested nauplii. Results showed that vitamin C and FA, specifically HUFA accumulation were observed in oils enriched Artemia nauplii but better in 24 h compare to 12 h. Based on the overall performance, the best enrichment protocol for the fatty acid and vitamin C enrichment of A.urmiana is using ICES30/4 with 20% vitamin C level for 24h period (P<0.05).

In this investigation, effect of photoperiod and light intensity on egg production and hatching success, in Acartia tonsa was surveyed in laboratory conditions. Samples were collected by the mesh of 100 microns zooplankton net from littoral zone of Caspian Sea. All tests in the five light treatments (photoperiod) 24: 00, 18: 06, 12: 12, 06: 18, 00: 24 (light / dark) and two light intensities 50 and 1000 Lux were measured. Result showed that the most level of the egg production observed in 18h dark and 12h light at low light intensity (50 Lux) and the lowest level of the egg production observed in 6h hours light in high light intensity (1000 Lux) and in completely dark. The highest percentage hatching in photoperiod of 18h light and high light intensity and a lower percentage of hatching was observed in the treatment of darkness.

This experimental work was aimed to study the chemical composition, fatty acid profile and fat soluble vitamins (E& D) in the liver of wild and Farmed Beluga (Huso huso). Four fish liver specimens of each of the wild and farmed beluga were obtained from Caspian Sea-Golestan catch station and fish hatchery, Ghorogh Talesh, respectively.Chemical composition, Calcium, Phosphorus, Fatty Acid Profiles, Vitamin E and Vitamin D were measured using standard methods. In farmed samples, average amount of moisture, ash, protein, fat, Phosphorus and calcium72.1±0.68%, 1.36±0.08%, 18.79±2.93%, 8.75±1.7%, 0.72±0.07%, 0.76±0.2 measured whereas this measure in wild samples were 62.36±6.56%, 1.26±0.013%, 11.06±.84%, 15.85±4.09%, 0.57±0.15%, 0.79±0.19%. Out of 25 Methyl Ester Fatty Acids (C12 to C22) in 7 cases there was a significant difference (P≤0.05) between wild and farmed samples. Saturated fatty acid C16: 0 and mono unsaturated fatty acid C18: 1 was found in considerable amounts in the liver of both wild and farmed samples. In the Caspian Sea' s samples and also in farmed samples the amount of Omega 3 (n-3) was 6.70% and 6.97% and the amount of Omega 6 (n-6) were 15.71% and 3.64% respectively. Alpha tocopherol levels in farmed and wild Huso huso was (1.05±0, 1.04±0.21 mg/kg), beta and gama tocopherol was (0.15±0.21, 0.058±0.041 mg/kg) and delta tocopherol was (0.058±0.056, 0.058±0.040 mg/kg) respectively. Vitamin D was not detected in both cases. Considerable percentages of valued parameter of vitamin E and Omega 3 suggest that Huso huso liver even in farmed samples has nutritional and medicinal values and with its industrial extraction can produce pharmaceutical products, promote the added value of fishery products and also help to decrease environmental pollution.

This study examined the ability of two enrichment mechanisms, bioencapsulation or/and attachment to the body surface of Artemia nauplii (Artemia franciscana) with two isolated Bacillus probiotics. The probiotics tested were Bacillus subtilis and Bacillus lechiniformis delivered at two concentrations (103 and 106 cells/ml). Results show that both species of bacteria could be bioencapsulated into and attached to Artemia successfully. For all treatments, the attachment of probiotic to Artemia increased, while bioencapsulated probiotic into Artemia decreased over time. With bacteria at 106 cells/ml, attachment levels reached 2.3±0.2×103 CFU/nauplius for B. subtilisand 3.2±0.1×103 CFU/nauplius for B. lechiniformis occurred. When nauplii were exposed to the probiotic bacteria at 106 cells/ml, maximum bioencapsulation levels were 4.2±0.2×103 CFU/nauplius with B. subtilis and 4.1±0.2×103 CFU/nauplius with B. lechiniformis.

In order to, study the ability of replacement of canola cake with fish meal, and its effect on growth performances; an experiment with 0, 5%, 10 %, 15%, 20%, canola meal cake instead of fish meal was conducted (in triplicate).Two hundred and 25 Cray fish with average weight 12±0.86 were randomly distributed between 15 fiber glass tank of 500 liter. During the experimental period, the dissolved oxygen level, temperature, and pH were maintained at 6.8±0.8 mg/L, 26±1.6oC, and 6.8- 7.9, respectively. Cray fish were fed at 5% of body weight in four times (6, 12, 18, 22 hours). The average performances such as relative growth rate (FGR), specific growth rate (SGR), protein efficiency ratio (FER) were shown no any significant between treatments (p>0.05).The highest final weight was observed in control basal diet (0% canola).Meanwhile the lowest final weigh has been observed in 20% canola meal replacement, though there was not observed statistically significant. Cray fish body composition such as crude protein, lipid, moisture and ash were not shown significant between treatments (P>0.05).The results of this experiment indicated that, the canola meal cake could be a suitable substitution with meal up to 20%.

Use of dietary supplement is a benefit way to improve the growth and nutrition performance and survival rate in fish intensive culture. Different researches have been done on dietary probiotics as benefit and applied supplements in fish nutrition. This study, was conducted to evaluate the effects of dietary probiotic bactocell (0.1, 0.2 nd 0.3 g/kg) on growth performance of common carp (Cyprinus carpio) with initial mean weight 15.49±0.12g in 60 days. Common carp Juveniles (118 fish), were randomly distributed between 12 fiberglass tanks with 500 L capacity. Each thanks contained 15 fish and fed four times a day (7, 11, 15 and 19 hr) to satiation. Determination of weight and length were done every 14 days. During 60 days of experiment, the fish which fed probiotic showed significantly higher growth performance in terms of weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), food conversion ratio (FCR) and survival rate (SR) in comparison with control (P<0.05). The best results in food efficiency and growth performance with significant differences (P<0.05) were observed in the treatment which fed 0.2g/kg of probiotic bactocell. Protein levels were higher in 0.2 g/kg probiotic treated fish but with no significant difference with other treatments (P> 0.05). Also lipid and ash content were higher in 0.2g/kg probiotic had significant differences with other treatments (P<0.05). The results of this study showed that supplement of 0.2g/kg of probiotic bactocell has positive effect on growth and proximate composition in juvenile carp.