Journal of Aquaculture Development
Year:2013 | Volume:7 | Issue:1|Papers Count:8

In the stages of fish rearing, one of the most important subjects is supplying food with high quality for larva. This food must be easily accepted and diegested with fish larva. Today, widely used live food, especially nauplius of artemia enriched with different materials is applied in the early stages of nutrition of many fish and shrimp species. Fluoride is one of the important minerals that reaches to human from drinking water and seafood such as shrimp and fish and is necessary for strengthen of teeth and bones. In this study, Artemia Franciscana (A. franciscana) was enriched with sodium fluoride in the Shahid Dr Beheshti Hatchery. Artemia cysts after removing the shell and 30 hours after the hatching were in Instar II stage. In this stage, they were enriched with sodium fluoride concentrations 40 and 80 and 160 mg/L and control (no enrichment), each with three replicates. Sampling from controls and exposed treatments was done 2, 4 and 6 hours after enrichment. Then samples froze and ashed in a furnace. The ashes treated with sodium hydroxide and fluoride was determined using potentiometric method through ion selective electrode. According to Duncan test results, interaction between time and fluoride concentration is significant (p<0.01).All of the enriched treatments showed statistically significant differences with control. Most absorption of sodium fluoride was observed at 40 mg/L treatment after 2 hours. Death of Nauplius Artemia was observed in the dose of 160 mg/L and in this concentration, intake of fluoride was not selective. Also, after 2 hours exposure till 6 hours, the concentration of fluoride was reduced in artemia that is probably due to excretion of fluoride from the body. Based on the obtained results, concentration of 40 mg/L Sodium fluoride with the time of 2 hours exposure is the best dose to enrich Artemia with fluoride.

A rearing trial was carried out to determine the effects of dietary soybean lecithin on growth performance, feed conversation and body composition of Persian Sturgeon, Acipenser persicus fingerlings, reared under culture conditions in Iran. The experimental period was planned as 60 days period in the International Sturgeon Research Institute. Four semi-purified diets were formulated to contain increasing percentages of commercial soybean lecithin (0, 1, 2 and 3%). 240 A.persicus fingerlings with an average weight of 1.9±0.1 g and an average total length of 7.0±0.3 cm were randomly allocated to 15 L of water (20 fish per tank) in 12 tanks. During the feeding trial the fish were fed daily to apparent satiation. The final weight and final total length in the fish fed diets supplemented with 1 and 3% of lecithin and without lecithin were significantly higher than diet supplemented with 2% of lecithin (p<0.05). Comparison of results obtained from condition factor revealed that there is a significant difference among fish fed diet 2% of lecithin and those fed 1 and 3% of lecithin and also control group. Survival rates in the fish fed diet supplemented with 3% of lecithin (%88.8±1.9) were statistically better than diet 1% of lecithin (% 73.3±11.5) (p<0.05). The highest specific growth rate (SGR) was recorded in fish fed diet supplemented with 1% of lecithin although no significant differences (P>0.05) were detected as compared with diets 3% of lecithin and control diet. The results obtained from carcass analysis reveal that values of the saturated fatty acids in A.persicus carcass decreased with increase in lecithin in diets.

In this trial, quantitative and qualitative monitoring of Acipenser gueldenstaedti fingerlings in Shahid Marjani (S.M) fish farm and Sadde Voshmgir (S.V.), that are major centers of producing sturgeon fingerlings for releasing purpose in Golestan Rivers, was done in 2002 and sturgeon Growth indices were compared between S.M. and S.V. In this case, the numbers of cultured A. gueldenstaedti in S.M. were 1400000 and in S.V. were 260000 pieces. The mean weight of A. gueldenstaedti in S.M. was 8.46±1.52 gr and in S.V. was 8.35±1.81 gr. The area that was considered for cultivating of A. gueldenstaedti in S.M. 14 ha, the number of released fingerlings 8864117 and survival rate was 63.3%, in 2002. Also, the area that was considered for cultivating of A. gueldenstaedti in S.V. 4 ha, the number of released fingerlings 65760 and survival rate was 25.29%. In this research, length frequency and weight frequency percentage in A. gueldenstaedti were investigated. Also, condition factor separately in S.M. and S.V. The results obtained in present study showed that released mean weight, condition factor and growth rate in A. gueldenstaedti did not significant difference in S.M. and S.V. (P>0.05).

Accordingly, in a three-year research during 1385, 1386 and 1387, the blood of 34 breeders of sturgeon (Acipenser percicus )16 male with mean weight 17.5 kg and 18 female with mean weight 18.5 kg were examined and the number of red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), hematocrite (Hct), red blood cell indices, i.e., Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration percentage (MCHC) were measured. In the survey results, there was significant difference between male and female blood factors such as Hematocrite, Hemoglobin, the number of Red and White blood cells among male and female breeders. This study shows that differences in blood factors related to gender.

Present study has been done in order to analyzing the influence of temperature and seasons of year on immunity and biochemical parameters of blood serum of rainbow trout (Oncorhynchus mykiss) in winter and summer in Neka and Haraz regions. In each season from each work shop randomly 15 samples with average weight of 100 grams were preyed and analyzed. Measuring the total weight and length has been done. After seasonal cupping in caudal vein and separation of serum by centrifuge, immunity parameters of blood serum include Igm, C3, and C4 and biochemical parameters of blood serum include albumin and total protein have been evaluated. The results of this research show that there wasn’t a meaningful difference in Igm parameters, total protein and albumin in the summer in Neka and Haraz regions (P>0.05). But there was a meaningful difference in C3 and C4 parameters that highest value were in Neka (P<0.05). In Igm, C3, C4 and Albumin in winter between two regions of Haraz and Neka there wasn’t any meaningful difference (P>0.05). Except than total protein, that there was a meaningful difference in it that highest value was in Neka (P<0.05). Generally, maintained results of this study shows that increasing the temperature in the scope of trout growth in two regions can be effective for immunity system performance and trout healthy.

Nowadays, research studies are important for growing the quantity and quality production in fish culture industrial. Phytoplankton is considered as main food sources for warm water fishes. Fertilizers were stimulated production of phytoplankton directly or indirectly. This paper is to study the effects of liquid cow manure on abundance, biomass, community structure of phytoplankton and chlorophyll-a amount in warm water fish ponds. Meanwhile, the comparison of the effects of three different types' fertilizers has been investigated. The ponds number 1 and 3 treated by liquid cow manure and chemical fertilizer respectively, and the pond number 2 treated using liquid cow manure and chemical fertilizer together. Results showed that the mean of abundance, biomass and chlorophyll-a increased in all ponds after fertilizing. Mean of biomass and chlorophyll-a in pond 3 were observed 5 and 0.06 mg/l, respectively, which were lower than mean of the values in the two other ponds (8 and 0.11mg/l). It seems that using of combine fertilizing (liquid cow manure and chemical fertilizer) is much better than any various types of fertilizer alone. Microscopic observation showed that the abundance of Cyanophyta and Chlorophyta was higher in pond with liquid cow manure than pond with chemical fertilizing. The most biomass of phytoplankton was formed by Chlorophyta especially spined cells in pond with liquid cow manure. As a conclusion, higher weight of fish, chlorophyll-a amount and phytoplankton abundance at the end of cultural period were shown the suitable selection of fertilizer in the pond which fertilized by liquid cow manure and chemical fertilizer together. However, inconvenience pond management such as lack of frequency manuring and lack of environmental controlling (low water level) were cuased undesirable pattern of dominant phytoplankton phyla and species for fish's nutrition.

The purpose of this study was to survey the effectiveness of education extension course on environmental awareness of aquaculturer in Guilan province, Iran. This is an applied and descriptive correlational research that was carried out as a field method. The study population comprised those aquaculturers of Guilan province who have been known as warm water fish trainers by fisheries office of Guilan province in 2010. It included two groups: trained Aquaculturers (n=27) and untrained aquaculturers (n=27).Data was collected by a questionnaire which its validity was reviewed by related experts and its reliability was determined with 15 pretest questionnaires and cronbach's alpha coefficient (a=0.76). The results indicate the satisfaction of more than 70 percent of respondents from training course. The results of this study showed that extension programs significantly affect environmental awareness of Aquaculturers. A significant difference was not found between environmental knowledge and awareness of aquacultures based on independent variables like age, work history and education Level.

Rainbow trout fish in the coldwater in addition to the production of early eggs from fertility and reproduction of broodstock in the country, the other countries, like Denmark, Norway, France, and America and so early eggs has been imported in our country. So, research between early eggs Danish, American and Iranian percentage of hatching and survival of the eggs, the growth rate and biological parameters (specific growth rate, condition factor, feed conversion, etc.). Statistical analysis revealed significance between the treatments (p<0.05). The highest average hatching rate (96.6±0.89), The highest average growth rate of weight (1.7±1.5), The highest average growth rate of longitudinal (47.07±15.9), the highest average weight gain percent (84.19±16.5), the best rate of food conversion rate (0.6±0.11) and the most specific growth rate (10.58±6.9) was related to the treatment of the Danish in comparison of American and Iranian.