Sperm characteristics in grass carp, Ctenopharyngodon idella effect of ions on spermatozoa motility and fertilization capacity

In this study, sperm characteristics (motility parameters and ionic composition of seminal plasma) and effect of ions on motility (duration of motility of sperm and percentage of motile spermatozoa) and fertilization capacity (fertilization rate, hatching rate, survival rate and larvae length) were investigated in Ctenopharyngdon idella. The longest duration of motility obtained in solution containing 104 mM NaCl. The highest fertilization capacity was observed in solution containing 112 mML NaCl. Solutions containing different concentrations of KCl caused a decrease on the percentage of motile spermatozoa fertilization rate and hatching rate, but duration of sperm motility and survival rate were significantly higher in solution containing 440 and 320 mM KCl, respectively. There was a decreasing trend on motility when spermatozoa incubated in solutions containing MgCl2 compared to the control. Similarly, higher motility parameters in terms of percentage of motile spermatozoa and duration of sperm motility were observed in distilled water. The sperm motility just after activation was suppressed by concentrations of CaCl2 of 32 mg/dL or more. The maximum hatching rate, survival rate and larvae length were observed in 32 mg/dL CaCl2. Understanding the effects of these ions is helpful to the aquaculture industry as it allows for the development of optimal artificial reproduction methods and contributes towards the knowledge base of better short-term fish semen preservation conditions

Variability in hematology and plasma indices of common carp Cyprinus carpio, associated with age, sex and hormonal treatment

The purpose of this study was to determine changes in hematological and plasma indices of common carp Cyprinus carpio with regard to age, sex and hormonal treatment. Sixty fish were used to assess the age factor. Also, 20 fish including female and male were assigned to determine blood indices with regard to sex and hormonal treatment. The pituitary gland extract was used as hormone for males and females. Red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), calcium, glucose, cholesterol, triglyceride, protein and phosphorus showed significant differences among ages. However, hematocrit (HCT), lymphocyte and neutrophil did not show significant differences. Statistical analysis revealed that males had higher values of RBC, Ht, Hb, MCV, MCH, lymphocyte, neutrophil and cholesterol compared to females. Some hematology and plasma indices influenced both sexes before and after hormonal treatment. These results provide useful information for monitoring changes in the health status of fish

Effect of age on reproductive efficiency of adult rainbow trout, Oncorhynchus mykiss Walbaum, 1972

Rainbow trout, Oncorhynchus mykiss is one of the most important cold water fishes in Iran. For successful artificial propagation of rainbow trout, the quality and quantity of brooders and sexual materials are key factors. In the present study, we investigated the age-dependent changes of reproductive efficiency. For this purpose, the brooders were divided into age classes and then three age groups of male and female (i.e. 3, 4 and 5 years old) selected randomly from each age class. At the time of propagation, total length and weight of brooders before and after stripping, egg diameter, total weight of stripped eggs and sperm quality parameters including sperm density and spermatocrit were measured. Afterward, the brooders were crossed randomly. According to our results, the higher percentage of fertilization (98%), hatching (96%), survival (94.5%) and also the larvae with more active feeding (n= 3070) were found when the 4 year old males were crossed with 5 year old females (p<0.05). Our results confirmed the age-dependent changes of reproductive efficiency in rainbow trout. We conclude that the cross between 4 year old males and 5 year old females of rainbow trout can enhance the reproductive efficiency

Growth performance, hematology and immunological parameters of rainbow trout, Oncorhynchus mykiss, fed with diets containing different levels of vitamin E and folic acid

This study was conducted to evaluate the effects of dietary levels of vitamins E (25, 30 and 35 mg kg^-1), Folic Acid (1.5, 2 and 2.5 mg kg^-1) and their combination on the growth performance, hematological and immunological parameters of rainbow trout, Oncorhynchus mykiss. Each diet was fed to rainbow trout in triplicate to apparent satiation four times daily for 8 weeks. At the end of the feeding trial, the final body weight (FBW), total length (TL), feed conversion ratio (FCR), specific growth rate (SGR) and survival rate were significantly affected by treatments and the fish fed with the diet containing 35 mg kg^-1 vitamin E plus 2.5 mg kg^-1 of folic acid had higher values than those fish fed with the other diets. The results also indicated that hematocrit (Ht), mean corpuscular volume (MCV) mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were significantly influenced by the treatments. Lysozyme and immunoglobulin (IgM) concentrations were significantly influenced by the dietary treatments, fish fed with the diet supplemented with 30 mg kg^-1 of vitamin E plus 2 mg kg^-1 of folic acid and unsupplemented diet had higher concentrations than those fish fed with the other diets. The findings of this study suggested that trout requires 35 mg kg^-1 vitamin E and 2.5 mg kg^-1 folic acid for it’s normal growth and physiology

Effect of male age in Caspian brown trout, Salmo trutta broodstock on reproductive performance

In this study, three different age groups of male broodstocks (4, 5 and 6 years respectively) were used to fertilize eggs obtained from nine females. The results showed that 6 year old males had maximum body weight (1766 g), total length (56.3 cm) and sperm volume (31.83 ml). Results did not show significant difference in spermatocrit and spermatozoa concentration among age groups (p>0.05). Our study showed maximum fertilization rate (98.5 %), survival rate until eyes pigmentation (91.17 %), hatching rate (94.5 %) and survival rate until absorption of yolk sack (97.16 %) for 4 years treatment group. Such positive relationships were detected between sperm production characteristics (spermatozoa concentration, spermatocrit and sperm volume) and fertilization parameters. Based on our results, it can be concluded that 4 year old males have high efficiency leading to fertilization success

Investigation on drought effects on diversity, frequency and distribution of benthic fauna in Amirkelayeh Wetland

The Possible effects of dry years 1998-2000 on benthic organisms of Amirkalayeh Wetland was studied in the year 2001. Six sampling stations were defined where we seasonally collected benthics organisms using a grab sampler. We identified nine benthic organisms belonging to class Hirudina and orders Odonata and Ephemeroptera and also six families Chironomidae, Chaoborina, Ammaridae, Tubificidae, Xanthidae and Culicedae. Families Xanthidae and Culinidae had not been reported before for the wetland while orders Coleoptera and Trichoptera and families Planorabidae, Limnaeidae, Coleoptera which were present before the drought, were not detected in the samples. We observed a significant decrease in frequency of benthic organisms changing from 1372 organisms per square meter in 1997 to 165 in 2001. Also, tests showed considerable change in benthic diversity, species richness and distribution in different sampling seasons and stations over the year 2001. These changes may be attributed to the decrease in water depth, dissolved oxygen, available food and increase in water temperature and predation

Species composition and abundance of fishes in Amirkelayeh Wetland

In order to determine the species composition and abundance of fishes in Amirkelayeh International wetland a series of seasonal survey were carried out in 2001-2002. The samples were collected by different methods of gillnet, beach seine, castnet, electroshocker and dipnet. After catching the fishes, they were transfered to the laboratory for further species indentification. A total of 1639 specimens were collected that belong to 7 orders, 9 families, 15 species and subspecies. The identification orders were: Cypriniformes, Salmoniformes, Syngnathiformes, Cyprinodontoformes, Siluriformes, Perciformes and Gasterosteiformes. Among different orders, the order of Cypriniformes and Gasterosteiformes and among different families, the Cyprinidae and Cobitidae and among different species, Perca jluviatilis and Scardinius erythrophthalmus had the most and the least abundance, respectively. The stock of Tinca tina and Esox lucius were so high. It should be noticed that three species of Cyprinus carpio, Scardinius erythrophthalmus and Cobitis taenia were found for the first time in this wetland

The effects of different dietary vitamin C and iron levels on the growth, hematological and immunological parameters of rainbow trout Oncorhynchus mykiss fingerlings

A 60-days growth trial was conducted in a flow-through culture system to examine the effects of different dietary vitamin C and iron levels on the growth, hematological and immunological parameters of rainbow trout (Oncorhynchus mykiss) fingerlings (with average initial weight of 5.12 ± 0.02 g). Three levels of vitamin C (150, 200 and 250 mg kg^-1 diet) and iron (5, 7 and 9 mg kg^-1 diet) (as ferrous sulfate) and their combination were used to prepare diets used in nine experimental treatments with three replicates. The results revealed that the supplementation of basal diet with vitamin C and iron significantly affected the final body weight (FBW), total length (TL), feed conversion ratio (FCR) and specific growth rate (SGR). Among the haematological parameters haematocrit and mean corpuscular volume (MCV) were significantly influenced by vitamin C and iron. Results also showed that lysozyme and IgM concentrations significantly changed among dietary treatments. Based on the results of this study, it can be concluded that addition of vitamin C and iron to the basal diet of cultured rainbow trout will improve the growth rate and well-being of this fish

Effect of age on reproductive performance of Kutum, Rutilus frisii (Nordmann, 1840) in Shirood River, the southern coast of the Caspian Sea

In this study, we investigated the age-dependent changes in reproductive efficiency of Kutum, Rutilus frisii caught from Shirood River, the Southern Caspian Sea (Mazandaran Province, Iran). Age-dependent reproductive performance of brooders was assayed on two age and sex groups. Results revealed that there were no significant differences in sperm characteristics between age groups. All female characteristics revealed change except relative fecundity between two age groups. The higher fertilization rate (87%) and also survival rate (91%) were found when the 4 year-old males were crossed with 4 year - old females (P < 0.05). Our results confirmed the agedependent changes of reproductive efficiency in Kutum. So that, the cross between 4 year-old males and 4 year - old females could be useful for enhancement of reproductive efficiency in Kutum

Studying fish biodiversity and abundance in Boujagh Wetland of Kiashahr, south-western Caspian Sea

The fish biodiversity and abundance studied in Boujagh wetland, close to Kiashahr south-western Caspian Sea during the year 2002. In each season, samples were collected by using gillnet, common haul seine, cast net and dip net in a 7-15 day sampling period and found one class (Osteichthyes), eight orders, nine families and 25 species and sub-species of the fishes found in the wetland. We showed that of the order Cypriniformes, two families of Cyprinidae with 14 species and sub-species and Cobitidae with two species are living in the wetland. Other fish orders were only represented by one family: Esociformes by family Esocidae, Syngnathiformes by Syngnathidae, Cyprinodontiformes by Poeciliidae, Siluriformes by Siluridae, Gasterosteiformes by Gasterosteidae, Atheriniformes by Atherinidae and Perciniformes by Gobiidae. Of these orders, Cypriniformes and family Cyprinidae had the most diverse fish species with Blicca bjoerkna being the most abundant