نشریه توسعه آبزی پروری
سال سیزدهم شماره 1 (بهار 1398)

The present study examined the effect of date pits powder as a low-cost and nutritive carbohydrate source compared to wheat, rice and corn meal in the diet of Pacific shrimp. The date pits meal was applied to the diet at the levels of 0 (control group), 5, 10, 15 and 23%, and the growth performance of shrimp was examined in 8 weeks. The results showed that the weight and length gain, specific growth rate (SGR), and condition factor of shrimp fed diets contained different levels of date pits meal were not significantly different compared to control group (p>0.05). The condition factor was close to 1 in all the treatments. Altogether, this study showed that the date pits meal could be applied up to 20% as an endemic and low-cost carbohydrate source in the diet of farmed shrimp and replaced by other energy providing sources including wheat meal without any adverse effect on shrimp performance.

This study carried out to investigate the fluctuation of benthic population in cages of rearing trout (Oncorhynchus mykiss, Walbaum, 1792) in depths of 30-25m of southern part of Caspian Sea at Nashtaroud region of Mazandaran province, This study was performed 150 days with measuring and evaluating physico-chmical factors of water during 5 phases up to the end of rearing period .Samples collected by Ekman Grab was 3 replicates in and out of cages, monthly. In order to investigate population of benthic, some indices such as Shanon-wiver,Simpson and Margalof are used to determine diversity dominance and enriching of species. Totally, 200 specimen of invertebrates (g/m2) belonging to 3 families Bivalvia Molluscas, polychaeta worms and Crustacea collected. The maximum and minimum biomass belongs to Abra ovata 49.2 gm-2 and species like Nereis diversicolor, Balanus improvises and Mytilaster lineatus 1gm-2 respectively. The results of study on organic material showed significant differences in the stations, so that highest was seen in west of cages and the lowest seen inside the cages (P<0.05). There is significant correlation between density and biomass of benthic and percent of mud in the bottom (P<0.05). The results showed positive correlation between Shannon diversity index and biomass of benthic (p=0.001; r= 0.684). Results showed that although after the introduction of salmon cage rearing larvae statistically significant difference was observed in the diversity and density benthoses (P<0.05),but the changes in the diversity of macrobenthose have been very little and partial in the established rearing cages. According to ecological of Classification was done educational platforms studied were placed in stressful and polluted.

Among vertebrates, most of the fishes are unique for the lack of acrosome in their spermatozoa. The sperm enters the egg through micropyle of the egg. This has facilitated heterologous fertilization in many fishes and led to hybridization and polyploidization. Hybridization is performed both in the nature and domesticated fishes. Today, some of the hybrids have high growth rate than their parents so artificial hybridization be carried out among some economic species. Some of hybrids have high similarity to their parents, so identification and verification of hybrids is impossible. This identification needs both phenotypic (morphometric and meristic) traits and molecular analysis in compared with parents. In this case, the most confidence and the quickest method are molecular markers based on DNA, especially microsatellite markers. It could play an important role in the precise confirmation of fish hybrids.

In this study, effect of  replacement of fish meal by  Poultry by product meal  on  growth index,  biochemical and immune parameters of  Huso huso with average weight 108.83±5. 9gr ± SD that reared in fiberglass tank (2000 lit) for  8weeks were investigated. Six test diets (contain 42% protein and 18.5 Mj kg-1 energy) were prepared. Fish meal substituted by poultry by product  at 20% (PBM20), 40% (PBM40), 60% (PBM60), 80% (PBM80) and 100% (PBM100), respectively. In the end of nutrition period no significant difference were detected between Final weight (FW), Weight gain (WG) and Specific Growth Rate of fish fed (PBM0), (PBM20), (PBM40), (PBM60) and (PBM80) respectively )P>0.05(. Also, no significant difference by body protein were recorded between PBM00, PBM40, PBM60, PBM40 and PBM100, respectively) P>0.05(. but increasing of replacement led to decreasing of body lipid (P<0.05) .Catabolic enzymes (Aspartat amino transferase and Alanin Amino Transferase) were not affect by inclusion of poultry by product but plasma lysosyme was significantly higher than in PBM20compared to PBM 80 and PBM 100 (P<0.05). The result showed that high replacing of fish meal by poultry by product were not negative effect on growth index, biochemical and immune parameters of Huso huso in growth stage.

This study has been in order to investigate the effects of cage culture in the south of the Caspian Sea, Kelarabad. Sampling was in three direction of cages, East, West and South (the coast of Caspian Sea). For this purpose, four stations on each side of the cages was considered in terms of distance, the shadow (5 meters) to a distance of 1000 meters cages (control). Grain size analysis shows, the silt - clay (particles smaller than 63 microns) with mean (25/44- 98/4) and the average percentage of total organic matter (TOM) in deposits with mean (1/74-7/21). As the results show in all of the period of fine-grained particles was silt particles (mm ˂0/063), The highest the percentage of total organic matter at  station 3, and the highest percentage of organic matter showed in Station 3 (100 meter) to early (January), where it can because of sea currents (silicon and anti-silicon) from West to East. The results showed that the abundance of benthic invertebrate in station 4 (control) was higher than in the shadow of cages, which can be due to the cage culture and water flow. The lowest of the biomass was in the shadow of the cages and the highest was in station 3 (100 meters), in which can be due to presence of big species and high resistance to unstable conditions governing the location of marine cages to depend Cerastoderma lamarcki. According to the water flow that move and carry more organic matter from where the cages to this point has led to an increase in biomass. Shannon index range was determined between 0/29- 0/92 that reflects the diversity is low of the study area. Measurement of biological indicators such as diversity, abundance, indicator species, slight differences between the station bottom of cage and the station away from the cage, showed that some of these differences may be caused by fish farming in cages.

The aim of this study was to evaluate the effects of lactobacillus plantarum probiotic in diet on some nutritional indices as well as survival rate in Siberian sturgeon (Acipenser baerii). This research were randomly designed in three treatment and one control groups in three replications with probiotic-contained diet, e.g. 107, 108 and 109 probiotic bacterial cells per gram food and the control group with no probiotic, which were treated for 60 days and then evaluated. 240 numbers of 37.666 ±1.094g of Siberian sturgeon were randomly distributed on 12 fiberglass ponds. Results showed that the used probiotic bacteria was able to strengthen the growth parameters (weight, FCR and PER) and significant increase in PER indicators and significant reduction in PER in treated with probiotics groups compared with the control group. In this study, the treatment with log8 L. plantarum indicated significant differences between all treatments and control. The survival rate in all treated and control groups were 100 percent. The results showed that the L. plantarum probiotic work as a growth promoter in Siberian sturgeon.

This study was designed to compare the effects of different levels of mineral selenium in diet on growth performance, some blood indices and juvenile beluga carcass composition (Huso huso) within 10 weeks. For this purpose, a number of 315 fry with an average weight of 15.66 ± 0.77 grams were stocked in the twenty-one 500-liter fiberglass tanks (15 per each). Seven diets containing different levels of selenium, including 0, 5, 10, 20, 40, 80 and 160 milligrams per kilogram diet with equal amounts of protein and fat, was formulated and placed at the disposal of the fish. During the breeding period, fish were fed manually three times a day. The process of growth results showed that at the end of breeding period, fish fed with the diets containing 10 to 20 mg of selenium per kg of diet had significantly higher weight gain (WG), condition factor (CF), and Hepato somatic index (HSI) than the fish fed with other diets (P<0.05). In addition, the lowest average of the above mentioned indices was observed in 160 milligram of selenium in diet. Furthermore, the fish fed with the diets containing 10 to 20 mg of selenium per kg of diet had significantly lower feed conversion ratio (FCR) than the fish fed with other diets. By increasing the amount of selenium to 160 mg per kg diet, protein and fat levels of carcass decreased significantly, and the moisture of carcass increased notably. In addition, in comparison to the fish fed with the diets containing 80 to 160 mg of selenium per kg of diet, blood indices (WBC, RBC, Hb, PCV, MCV, MCH, MCHC) of fish fed with the diets containing 10 to 20 mg of selenium per kg of diet improved significantly (P<0.05). According to the results of this study, it can be admitted that, addition of selenium in the diet of young farmed baby beluga, at the levels more than 10 and less than 20 mg/kg of diet, could increase the growth process, improve the nutrition and carcass composition, and reinforce many blood indices

This study was done on wild common carp and main aims were determination of relationships between fecundity and the fish weight, length and age. One hundred individuals of pre-spawning females with a body weight 285.1-5483 g, total length 27.9-67.1 cm and age 4-12 years old, were sampled in Anzali wetland in 2016 and 2017. A mix subsample was sampled of eggs from front, middle and back parts of ovaries and batch and annual fecundities estimated basis on large eggs and large, medium and small eggs, respectively. The results showed an estimation of 11312-1280460 (170977.6±176651.3) for batch fecundity, 19773-1504448 (228978.1±216295.5) eggs for annual fecundity and 39400-286500 (132400±62400) eggs for relative batch fecundity and 69400-394300 (185400±75200) eggs per one kilogram of body weight for relative annual fecundity. The Pearson correlation coefficient was determined 0.93, 0.84 and 0.71 between batch fecundity and body weight, total length and fish age, respectively and 0.89, 0.81 and 0.72 between annual fecundity and body weight, total length and fish age, respectively and correlation was significant in all of them at ɑ=0.01, too. The averages of batch and annual fecundities increased regularly and significantly (p<0.05) with increasing of the fish size (length and weight) and age. This study stated a more fecundity for wild common carp in Anzali wetland than Golestan shore and it can verify difference in carp populations in southern Caspian Sea as an indicator.

Temperature is one of the most important environmental factors affecting of fish embryos and the survival and growth of fish larvae. In this study, eyed eggs of rainbow trout were incubated and reared until 30 day after first feeding at three constant temperatures including 7, 11 and 15 °C with four replicates in order to observe their survival, growth, rate of development and some physiological parameters. Triplicate pools of 5 embryos or larvae were taken at 7 different stages and then immediately deep-frozen in liquid nitrogen until analysis. Development rate was significantly different between temperatures. There was significant survival rate among the treatment groups (P < 0.05) at different stages, indicating different optimum temperature at different life stages. Survival at eyed stage to hatching stage at 7 and 11 ºC were significantly higher than 15 ºC. Survival at hatching to Swim up stage at 7 ºC were significantly higher than that of 11 and 15 ºC, but survival of swim up to 30 DAFF at 15 ºC were significantly higher than 7 and 11 ºC. Cumulative survival of 7 ºC was significantly higher than 11 and 15 ºC groups. Final weight was significantly higher at 15 ºC. So that mean weight at the end of experiment were 342.57, 596 and 1116.29 mg for 7, 11 and 15 ºC groups, respectively. A two-way analysis of variance showed that developmental stage and temperature had significant overall effects on total protein and total immunoglobulin, and there was a significant interaction among factors. In the case of albumin and Albumin/globulin ratio, Temperature had no main effect on albumin and Albumin/globulin ratio but stage showed a main. The interaction effect was significant too. In conclusion, although the egg incubated at 15 ºC had lower survival rate at early stages, but subsequent higher survival after emergence and faster growth may be an effective way to reduce larval mortality and better larviculture management.

The aim of the project is to assay the effectiveness of different values ofLHRH-a2 combined with carp pituitary extract in 3-stages way on reproduction indices of Arabibarbus grypus that belong to Cyprinidae family and is a native fish in Khuzestan province. Fifty individuals of fish in 4 treatments were studied. Control treatment were injected by 4mg/kg pituitary extracts, first treated: 4mg/kg CPE+ 3μg/kg LHRHa2, second treatment: 4mg/kg CPE+7μg/kg LHRHa2 and third treatment: 4mg/kg CPE+ 10μg/kg LHRHa2, that 40 fish were treated by 3-stages and 10 fish by usual way, were studied and the reproduction indices such as obtained egg and alive baby were measured. The results obtained that the weight of obtained egg (692 ± 111.2), relative fecundity (41.9 ± 3.22), fertilization (94.4 ± 0.89), hatching rate (98.2 ± 0.84), larvae number (10912.8 ± 1817.93), alive percent of baby (70.5 ± 2.3) was increased in second treatment (3-stages way) compared to the other treatments (usual way) (p <0.05). Therefore, 3-stages way in the second treatment dose (4mg/kg CPE+7μg/kg LHRHa2) is the best used way and concentration for artificial reproduction of Shabout brood stock.