JOURNAL OF AQUACULTURE SCIENCES
Year:2015 | Volume:3 | Issue:4 |Papers Count:7

Bacteria and zooplankton are important components of the pelagic food web and major contributor to biogeochemical processes. In this research, the dominant bacteria associated with culture media of cladoceran (Daphnia magna) and copepod (Acanthocyclops robustus) fed on manure (cattle+poultry, 1: 1 ratio in weight), vegetable (spinach+parsely+coriander, 1: 1: 1 ratio in weight), and algae (Scenedesmus quadricauda) were investigated. Results showed that D. magna fed on manure and vegetable had bacteria of Acinetobacter and with had Aeromonas bacterias while A. robustus fed on manure, vegetable and Scenedesmus dominated by bacteria of Neisseria, Enterobacteria and Alcaligenes, respectively. Effects of different diets were significant (P<0.05) on D. magna and A. robustus densities, bacterial density, BOD and COD of culture media. The highest bacteria density was obtained in D. magna culture medium fed on Scenedesmus (5´104 cell/ml) and the lowest on manure (9´103 cell/ml). In addition, at A. robustus cultures the highest and lowest bacteria were obtained 1.4´104 and 5.0´103 cell/ml, respectively. The maximum BOD was recorded on A. robustus fed on vegetable (90 mg/l) and minimum by D. magna fed on manure (28 mg/l). The maximum COD (313 mg/l) and minimum (43 mg/l) were recorded by A. robustus fed on vegetable and Scenedesmus, respectively. In addition, the parameters of BOD, COD and bacteria density had significant correlation with density of D. magna and A. robustus. As conclusion, findings of this research illustrated that type and density of bacteria were changed in different zooplankton culture media which depended on zooplankton species and their diets during cultivation.

In this study, the effects of semen diluent solutions on improvement of reproduction performance, by using the criteria such as: the rates of fertilization, percentage of eyed egg and hatching rates were studied. For this purpose eight female broods with average weight and length 1545.62±295.43 g and 54.37±3.85 cm, respectively and sixteen male broods were selected with average weight and length 623.08±180.69 g diluent solutions and 38.91±5.40 cm, respectively. After separation of eggs from coelomic fluids, they were fertilized with sperm using four different diluent solutions: 1- 5.54 g NaCl, 2.422 g Triss, 3.57 g Glycin, regulated in pH=8.4 and solution in 1L distilled water.2- 7.305 g NaCl, 0.735 g CaCl2.2H2O, regulated in pH=8.4 and solution in 1L distilled water.3- coelumic fluid that was separated from egg by using net and 4- distilled water as control treatment. The results showed that motility duration of sperm in 1th, 2nd, 3ed and 4th treatments was 65.25±7.36, 30.8±12.83, 73.33±2.117, 40.00±1.61 sec, the duration of forward movement was 6.25±4.71, 15.00±12.63, 52.33±1.90, 34.66±2.51 sec. and percentage eyed eggs was 16.82±6.42, 53.00±4.66, 82.50±3.84, 73.33±2.08, respectively. Percentage hatching was 55.05±5.42, 71.43±0.81, 49.60±6.25, 37.72±4.32, respectively. The results of spermatology parameters, eyed egg percentage and hatching rates showed a significant differences between the 2nd treatment with the rest (p£0.05). Thus, it can be suggested the 2nd treatment is an effective diluents solution for improving breeding performance of S. zarudnyi.

Sustainable aquaculture in each region is determined based on the domestic and international economic and it should be taken into account in fisheries researches. The purpose of this study was to develop an appropriate strategy for ornamental fish market in Alborz Province based on the SWOT analysis. A list of strengths, weaknesses, opportunities and threats, on the basis of the production and marketing of ornamental fish, was prepared using a set of questions within the frame work of matrix, evaluating the internal and external factors. Total scores according to the results for the internal and external matrix elements were 3.61 and 3.68, respectively, which both are above the average number and show the correct use of the ornamental fish industry to overcome weaknesses and threats using the strengths and opportunities. The aggressive strategy was proposed according to the findings of external and internal factors for the development of ornamental fish market in Alborz Province. Besides, strategy of new methods for ornamental fish culture followed by the increased investment in culture section of ornamental fish based on the QSPM matrices had the highest attractions with the averages of 4.50 and 4.33, respectively. The use of new strategies and increased investment in the production of ornamental and aquarium fish on QSPM matrix with mean of 4.50 and 4.33 received the highest attraction score.

Polysaccharides are known as biopolymers and shown to play key roles in therapeutic agents. In current study we examined possible efficiency of freshly derived polysaccharide from the roots of Acanthophyllum glandulosum on blood indices of rainbow trout exposed to sub acute doses of mercury chloride.540 Fish were divided into three equal triplicate groups. The first treatment was control group, the second treatment tanks contained 60 mg/1 of an aqueous solution of Hg and the third treatment contained 60 mg/1 HgCl and 1% freshly extracted polysaccharide 24 h before introduction of fish to the tanks. Serum hematological and biochemical parameters were analyzed. Results of the present study showed some hematological levels were significantly adjusted in polysaccharide and mercury exposure group compared to mercury exposure groups. Adding polysaccharide had adjustment effects on some parameters including RBC, Ht, MCV and Cortisol. Polysaccharide had not significant adjustment effect on MCHC, MCH, Hb levels, protein levels and glucose. Finally, our results confirm that the new polysaccharide has useful effects on the host and probably act as a prebiotic that can improve the host health.

The aim of this study was comparative study of the effects of two prebiotics, oligofructose and inactive yeast, on intestinal microbiota of beluga (Huso huso). The study was done in a completely randomize design include feeding beluga with diet contain 1 or 2% inactive yeast and 1 or 2% oligofructose as well as a control group (5 treatments in triplicates). Beluga (11.40±0.56 g) supplied, 35 specimens stocked in each fiberglass tanks and were fed for 6 weeks with experimental diets. At the end of trial total viable lactic acid bacteria (LAB) and their proportion was studied using culture based method. Our results showed that administration of oligofructose or inactive yeast had no significant effects on total viable bacteria compared control group (P>0.05). The highest LAB levels was observed in 2% oligofructose or inactive yeast fed fish which was significantly higher than control (P<0.05). The proportion of LAB to total viable bacteria was significantly elevated in all prebiotic fed fish (P>0.05) and the highest proportion observed in 2% oligofructose fed beluga.

Due to the importance of aquatic nutrition from quality and economic aspects in aquaculture many studies have been carried out on the replacement, decreasing and omission of feed for organic aquatic production. The aim of this study has been complete omitting of artificial feed by using the synergistic effect of warm water fish polyculture. The study was performed for two consecutive years in “Amin Abad” aquaculture research center of veterinary faculty. Amongst the warm water fish; common carp as omnivore, silver carp as phytophagous and bighead carp as a zooplanktophagous fishes were used for this phenomenon study. The composition of fish in our polyculture system was as follows: 30% common carp, 65% of silver carp and 5% of big head carp, initial individual weight of 4.5 g, 30 g and 30 g, respectively. In the first year after 206 days the final weight of common carp, silver and big head carp were 850 g, 712 g and 1750 g, respectively. While in the control mono species culture, the final weights of common and silver carp were 365 g and 375 g, respectively. In the second year the rate of production in synergical culture without consuming feed was 4912.4 kg/ha, whereas, in control system with the artificial feed was 4817 kg/ha. The results of this study showed that suitable individual growth of fish species, the higher total production and the total prices due to omission of feed in synergistic culture achieved the more benefits than the control cultures of warm water fish consuming the artificial feeds.

In this study, the effects of different amounts of dietary copper and zinc on serum parameters related to bone metabolism in common carp was determined. Fish weighting 56.56 ± 22.43 g were divided into 5 groups (12 individual/group), were fed at a rate of 3% of body weight for 8 weeks. The Diet contained copper (1 and 3 mg/kg diet) and zinc (7.5 and 15 mg/kg diet) and a control dietary group with no addition of copper and zinc. At the end of the experiment, 8 fish were chosen randomly from each tank and blood samples were taken from the caudal peduncle. Then, serum parameters related to bone metabolism, including calcium, inorganic phosphorus, magnesium, vitamin D3 and alkaline phosphatase were measured. The result showed a significant increase (P<0.05) in serum calcium concentration following Cu2 treatment in comparison with control treatment. Serum phosphorus were reduced significantly in Zn1 and Cu1treatments as compared with control. Although the amounts of serum magnesium and vitamin D3 were elevated in some treatments, the overall changes did not show significant differences (P>0.05). Significant reductions (P<0.05) in the activity of alkaline phosphatase were observed in all treatments compared with controll group. Generally, increase in the levels of the copper and zinc in diet, by changing serum parameters related to bone metabolism can affect bone formation to some extent in common carp.