fertilization

Caspian trout, Salmo caspius, Kessler 1877 is an anadromous form of brown trout. In vertebrates, the functional receptors of THs, including thyroid hormone receptors (TRs) (thrα, thrβ). In developing fish eggs, the expression of THRs has been reported in different time periods. The ontogeny of the thrβ in the eggs of Caspian trout (Salmo caspius) has been investigated in the present study. The sampling of ova was done before and post fertilization, 24 and 48 h post fertilization, eyeing stage, hatching and CYA while being exposed for 1 h to various thyroxin hormone concentrations including 0 (control, without hormone), 0.25, 0.5and 0.75 mgL-1. The statistical analysis showed increased gene expression of thrβ during the development period. An inverse relationship between hormone concentration with eyeing and hatching percentage were detected in the eggs. In summary using thyroxin hormone by applied doses to achieve better fertilization efficiency not recommended.

During gonadal development and sexual maturation in fish, the metabolic rate in these tissues increases rapidly, generating a substantial number of free radicals (Fernandez-Palacios et al., 1998; Izquierdo et al., 2001). Research on various fish species has shown that incorporating high levels of vitamin E into fish diets reduces larval deformities, improves fecundity, enhances larval quality and development, and increases antioxidant resistance in eggs (Nascimento et al., 2014; Erdogan and Arslan, 2021). Conversely, a deficiency of vitamin E in the diet of female broodstock can lead to the development of immature gonads, reduced egg fertilization, lower hatching rates, and decreased larval survival (Miller et al., 2012). During vitellogenesis in various fish species, vitamin E is transported by lipoproteins from visceral tissues to the ovaries (Lie et al., 1993; Hemre et al., 1994; Tokuda et al., 2000; Huang et al., 2019). For instance, in Japanese flounder (Paralichthys olivaceus), dietary supplementation of vitamin E at 1000 mg/kg has been found to enhance vitellogenesis, as well as the transfer and storage of this vitamin in the ovaries (Tokuda et al., 2000). Similarly, in turbot (Scophthalmus maximus), the addition of vitamin E to the diet has been shown to stimulate the synthesis and secretion of reproductive hormones, specifically follicle-stimulating hormone (FSH) and luteinizing hormone (LH) (Huang et al., 2019). Acanthopagrus arabicus, commonly known as the yellowfin seabream, is a carnivorous species belonging to the family Sparidae. It has been recognized as a promising candidate for the development of cage aquaculture along the southern coasts of Iran (Torfi Mozanzadeh et al., 2021). However, there is limited information regarding the vitamin requirements of this species, particularly for broodstock. Therefore, the present study was conducted to investigate the effects of vitamin E supplementation on the reproductive and physiological performance of A. arabicus.

Initially, broodstock aged 1 to 2 years were captured by fishermen using hook fishing methods in the Khormousi fishing area, beginning in mid-November. The broodstock of A. arabicus was maintained in two concrete tanks, each with a volume of 10 cubic meters, at a density of 10 fish per cubic meter. Vitamin E was prepared at seven concentrations: 0, 25, 50, 100, 250, 500, and 1000 mg per kg of diet. The broodstocks were fed the experimental diets for 60 days before the onset of the breeding season and 75 days during the breeding season (from early March to mid-May). The experimental diets were provided to the broodstock twice daily (at 9:00 AM and 3:00 PM) until satiety was achieved. Spawning occurred naturally at the water temperature of 19°C. To collect the released eggs, the water inflow was shut off at 6:00 PM, and floating eggs were collected the following morning at 8:00 AM using a funnel net (300 micrometers). The formulas referenced by Safari et al. (2021) were then used to calculate spawning rates, fertilization rates, and other reproductive performance indicators. The Kolmogorov-Smirnov and Levene tests were employed to assess the normality and homogeneity of variance in the data. A one-way analysis of variance (ANOVA) followed by Duncan's multiple range test was conducted to evaluate the effects of dietary vitamin E on reproductive responses. Additionally, orthogonal polynomial regression analysis was used to examine the relationship between reproductive factors and the dosage of vitamin E in the diet.

The inclusion of varying vitamin E concentrations in the diet did not significantly affect the female broodstock's final weight, condition factor, hepatosomatic index, viscerosomatic index, or gonadosomatic index. Broodstock fed a diet containing 250 mg of vitamin E per kg exhibited the highest relative fecundity. The duration of spawning in broodstock fed diets containing 100 and 250 mg of vitamin E per kg was significantly longer compared to other treatments (P < 0.05). The highest fertilization rate was observed in fish fed the diet supplemented with 250 mg of vitamin E per kg, while the control group exhibited the lowest fertilization percentage. Furthermore, the highest hatching rate and survival rate of three-day-old larvae were recorded in the group receiving 250 mg of vitamin E per kg. The lowest incidence of abnormalities during embryonic development occurred in the group fed a diet containing 50 mg of vitamin E per kg. The relationship between fertilization percentage, hatching rate, and larval survival indices with dietary vitamin E concentration followed a quadratic pattern.

 The findings indicate that vitamin E supplementation did not significantly affect the growth indices of the broodstock. This lack of impact may be attributed to the allocation of energy and nutrients toward gonadal development, maturation, and gamete production, which likely reduced the energy available for somatic growth during the breeding season (Safari et al., 2021). Vitamin E plays a critical role in the synthesis of sex hormones in animals and has been shown to promote the accumulation of yolk granules in the ovaries as well as gonadal development in fish (Zhang et al., 2007). In the present study, the inclusion of 250 mg of vitamin E in the diet of female A. arabicus resulted in enhanced fecundity, prolonged spawning duration, improved fertilization and hatching rates, reduced embryonic abnormalities, and increased larval survival. Similarly, the addition of 200 mg of vitamin E to the diet of the swamp eel (Monopterus albus) has been reported to promote gonadal development, increase spawning activity, and enhance hatching rates (Zhang et al., 2007). Furthermore, a study on a cichlid species (Pseudotropheus socolofi) demonstrated that incorporating vitamin E at a concentration of 219.3 mg per kg significantly increased egg diameter, fecundity, spawning frequency, fertilization rates, hatching success, and larval survival (Erdogan and Arslan, 2019). Studies indicate that vitamin E can regulate reproductive hormone levels and the expression of related genes during different developmental stages in fish (Zhang et al., 2021). Vitamin E is a fat-soluble compound essential for fish health and reproduction, acting as a structural element in cell membranes with antioxidant properties (Griesh et al., 2024). The results of the present study suggest that supplementing the diet with 250 mg of vitamin E improves reproductive efficiency and larval survival rate in the female Arabian yellowfin seabream (Acanthopagrus arabicus).

In this study, the sperm quality indicators of rainbow trout breeders in selected Specific Pathogen Free (SPF) farms of the country were investigated in order to plan the long-term preservation of rainbow trout sperm through cryopreservation and creating a sperm bank in the next phase. Sperm samples from 24 breeders from six selected SPF farms from West-Azerbaijan and Mazandaran provinces were collected and evaluated. The average density of sperm is 7.83 ± 4 billion per milliliter, the average volume of extracted sperm is 9.2 ± 1.6 ml, the average percentage of motility and its duration were 78.7 ± 10.3% and 26.6 ± 4.4 seconds, the average pH was 7.74 ± 0.23 and the fertilization percentage of the samples was as 92.8 ± 1.2%. The results showed that the pH 7.7-7.8 is the most appropriate value for inducing motility and its increasing or decreasing relative to this value causes a decrease in fertilization efficiency. Also, a positive correlation between pH and sperm motility (r = 0.533) and fertility (r = 0.67) was determined. According to the obtained information, the characteristics of the best sperm sample is selected for long-term storage and the creation of a genetically diverse sperm bank and targeted management of rainbow trout reproduction.

By broodstocking and propagating of specific pathogen-free (SPF) rainbow trout in Iran, the need to create a cryopreserved sperm bank from the breeders was deemed necessary. In this study, after evaluation of four different extenders for rainbow trout sperm cryopreservation, the best extender (0.6M sucrose and 8% DMSO) has been selected. The sperm samples were obtained from 24 breeders, including four breeders from each of the selected specific pathogen-free farms of the country in Mazandaran and West Azerbaijan provinces (Sarshar, Maroufi, Fakhari, Hadidi, Malekitabar, and Qorbani) were cryopreserved after qualitative evaluation. The fertilization test of sperm samples on the day of sampling and comparison of their fertilization percentage with frozen-thawed sperms in three time intervals (4, 24 and 48 hours) did not show any significant differences between the sperm of the control group and the frozen-thawed samples. The results indicated that the method used in this research can be well used in cryopreservation the sperm of SPF rainbow trout breeders and if needed, the sperm obtained from the best breeders can be transferred to other centers with this method.

In this study, the effects of dietary addition of vitamin C, astaxanthin, and lecithin on the fertility ability (percentage of fertilization and eyed-eggs) and activity of SOD, CAT and GPx in the ovarian fluids of Caspian trout (Salmo caspius) were investigated. For this purpose, nine different experimental diets: C0A0L0 (0 mg kg-1 vitamin C, 0 mg kg-1 astaxanthin and 0% soybean lecithin), C300A50L0, C700A100L0, C0A50L6, C300A100L6, C700A0L6, C0A100L9, C300A0L9, and C700A50L9 were formulated and the broodstocks (2.51±0.05 kg) were fed for four months. After sexual maturation and spawning, the ovarian fluids were isolated to measure the activity of antioxidant enzymes (AAE) and to evaluate its fertilization ability. The sperm mixture of 9 male broodstocks was used to measure fertilization ability. The results showed an increase in the relative fecundity and AAE in ovarian fluid. The lowest relative fecundity (680±38 eggs per Kg of broodstock weight) and SOD, CAT, and GPx (816.33±67.60 u/ml, 1.29±0.40 nmol/min/ml and 1.06±0.08 nmol/min/ml, respectively) were observed in C0A0L0 which significantly different from other treatments (p<0.05). The highest percentage of fertilization and eyed-eggs were obtained in C300A100L6 (91.66±5.13% and 87.63±1.3%, respectively) which significantly different from the freshwater treatment (77.66±4.16% and 47.86±5.1%, respectively; p<0.05). According to the results of this research, adding of 300 mg kg-1 vitamin C with 100 mg kg-1 astaxanthin and 6% lecithin can increase the relative fecundity, fertilization ability and AAE in ovarian fluids of Caspian brown trout.

Induction of gynogenesis requires the spermatozoa with degraded DNA with high motility, simultaneously. In this study, to obtain this capability in Siberian sturgeon spermatozoa, UV radiation with a dose of 4257 j/m2 was applied. First, the seminal fluid was separated from the spermatozoa using a centrifuge, and then 10% of the sperm was prepared and irradiated with UV radiation for 30, 60, 90, 120, and 150 seconds to obtain the best motility and percentage of DNA damage using the comet assay method in comparison with the control. Simultaneously, the fertilization ability of these sperms was tested in sterlet sturgeon eggs and the rate of hatched larvae. Based on the results, the best duration of irradiation of spermatozoa was determined to as 90 seconds. The DNA degradation rate was 32.27±1.96 percent, the motility rate was 50% with forwarding movement, the fertilization rate was 52.1±0.52 percent, and the egg hatching rate was 1.1±0.11 percent. Therefore, genetically inactivated Siberian sturgeon sperm could be used in interspecific gynogenesis studies in sturgeon. Either to producing offspring of all females or to protect their extinction.

Temperature is the main environmental factor affecting the development of fish eggs. In this study, the effect of incubation temperature on fertilization rate, hatching rate and growth in goldfish (Carassius auratus) was investigated. Egg and sperm production were obtained by ovaprim injection and artificial propagation. Eggs were incubated at four temperatures (21, 24, 27 and 30 °C) with 3 replicates for each treatment and cultured for 40 days at the same temperature. The larvae were grown in the same aquarium that had been hatched under the same temperature condition for 40 days. The results showed that there was no significant difference in fertilization rate of incubated eggs at different temperatures, but the highest (97%) and lowest (94%) fertilization rates were observed at 24 °C and 21 °C, respectively. The maximum incubation time was recorded at 21 °C and the minimum time required at 30 °C (P < 0.05). The highest percentage of hatching (74.4%) was observed at 24 °C and it decreased with increasing water temperature (P < 0.05). Although, the temperature of 30 °C showed the highest value of length, weight and specific growth rate of larvae in comparison to other temperature treatments, but the highest anomalies (13%) were observed in this treatment, too. The best temperature of incubation and growth of larvae is 24°C and 27°C for goldfish, respectively.

In this research, the effect of organic fertilizers was studied on the growth performance of carps fry. This experiment was conducted in a completely randomized design with seven treatments and three replications in 300 liters of tanks within 3 months. 60 pieces of fish fry with an average weight of 0.6 ± 0.05 g were randomly storage in each tank per 0.5: 1.5: 2: 6 (respectively, 5%, 15%, 20% and 60% respectively big head, grass carp, common carp, silver carp). Seven treatments were included control (C), vermicompost of 1 kg/m3 (T1), vermicompost fertilizer  1.5 kg/m3  (T2), compost fertilizer 1 kg/m3  (T3), compost fertilizer 1.5 kg/m3 (T4), cow manure 1 kg/m3  (T5), chicken manure 0.6 kg/m3 (T6) used in 3 replicates. Primary production, plankton and water quality parameters (temperature, chemical oxygen demand, dissolved oxygen, nitrogen-ammonium and phosphate) were measured weekly or twice weekly. At the end of the experiment period, the growth indices were measured. The results showed that the highest amount of dissolved oxygen, chlorophyll a concentration, phytoplankton and zooplankton was observed in T1 treatment and the lowest in control group (p<0.05). The highest amount of benthos was observed in T6 treatment compared to other group. Based on the results, the best growth performance was observed in T1 treatment, except to T6 treatment with other treatments (p<0.05). Overall, the results of this study suggest that vermicompost application of 1 kg/m3  can improve the quality parameters of water, plankton and performance of Carps fry.

This study was conducted to determine the effect of OvaprimTM and hCG hormones on induction of Perca fluviatilis in captivity, as well as examination of spermatological parameters of this fish. In the first treatment, 14 females with an average weight of 99.3±17.4 g were injected with a dose of 0.5 ml kg-1 body weight with OvaprimTM hormone. In the second treatment, 5 females with an average weight of 103.8±19.8 were injected at the dose of 500 international units per kg body weight with hCG hormone. In both experimental treatments, injections not performed in male broodstock. In order to determine the spermatological parameters, 10 males with an average weight of 92.0±13.1 g were used. According to the results, the fastest maturation time (1586.4 degree-hour) and the highest percentage of response (100%) were observed in hCG treatment (P<0.05). While the percentage of response in ovaprimTM treatment was 64.3%. The significant differences were not observed between two treatments in the average weight of swollen egg per fish, the average number of swollen egg per gram, percentage of fertilization, and hatching duration (P>0.05). Based on the results of this study, mean sperm volume of Perca fluviatilis was 1.3±1.1 ml, mean sperm activity was 80.5±15.31%, mean motility time was 155.4±57.7 seconds, mean percentage of spermatocrit was 84.3±11.4, and the mean spermatozoid concentration was 41.9±29.7×109 ml-1. The results of this study showed that to induce spawning of Perca fluviatilis broodstock in captivity hCG is more suitable than ovaprimTM. Considering the desirable effects of hCG, it is recommended that to induce spawning of Perca fluviatilis broodstock this hormone can be used.

Due to the growth in Aquatic system and their health and economic well being of forming system is very important.Hypophthalmichthys molitrix (silver carp) is one of the breading fish of cyprinus family that feed from phytoplanktons in water.Howere environmental condition of breading fileds mount be consider to obtain a optimal statu and fertilization of them to growth of biomass and diversity of phytoplanktons for growth silver carps. Shoshtar city is in east North of khozestan province with sustainable water rivers to breading of warm water fish.This study was started on biomass effect and density of phytoplankton on silver carp fry with 2.5 gr in polycalture farms. The stady was started from July 1391 and up to 45 days in Fourth stages of physical and chemical parameters of water Do, Temperatur, Electrical conductivity, Nitrate, phosphate,TDS, pH and chlorophyll a (biomass) as well as measurement and weight charachteries indetify and determine the length juveniles and phytoplankton concetrion with three replicates per treatment was carried out.The results showed that weight gain during the second trail of the same treatment were compared to the control treatment. Phytoplankton biomass based to measurement of chlorophylla (0.008±0.009 mg/l) showed and increasing in comparsion to the control treatment (p≤ 0.05). in general juvenile increased during treatment and had more weight show the control group.The amount of double fertilization treatments of silver carp juveniles increased in length and weight more than the control (p≤0.05). In general environment parameters expect dissolved oxygen, Ec and TDS were not significantlly different.

A completely randomized experimental design in triplicates was conducted to evaluate the effects of different levels of nitrogen with the constant level of carbon and phosphorous on production of warm water fish in Chapakrod fish farm in Joybar. The treatments were use of three levels of C: N: P, respectively, 1: 5.5: 88.6 (T1) 1: 7.5: 88.6 (T2) and 1: 9.5: 6.88 (T3). The mixed chemical fertilizers and organic manures consisted of chicken, cattle feces, vermi-compost, phosphate and urea mixed together to get different levels of CNP. The effect of different concentrations of nitrogen on phytoplankton abundance and chlorophyll, were investigated as well. At the end of experiment, the highest number of phytoplankton, chlorophyll, relative growth indices were significantly different (P

The appropriate quality of sperm whose important feature is movement , can cause increased fertilization. As the quality of sperms and ova were reduced at the end of the propagation period, and this problem may cause quality decrease of production, this research has been conducted in order to increase the efficiency of reproduction fertilization, by using activating solution at the mid of propagation season at the salmonid reproduction and conservation center of ShahidBahonar–Kelardasht in late 2012.In this regard, firstly 14 activating solutions with different component have been selected and were used in preliminary studies and finally, 7 activating solutions on the basis of compound and duration of sperm movement have been chosen for final surveys. In order to survey of the 7 selected solutions as well as distilled water, hatchery water (As control group) and physiology serum , on the duration of sperm movement, fertilization rate, eyed egg and hatching, 5 females and 5males of rainbow trout were randomly selected.Results showed that, among surveyed items, the activating solutions had significant difference comparing with each other and also the control group.The highest duration of sperm movement was produced by the number 1 (NaCl = 6gr/L,CaCl2.2H2O = 0.2gr/L , CO(NH2)2= 4.50gr/L, pH=7.6) and 6 (CaCl2.2H2O=./735 gr/L,NaCl=7/305 gr/L ,pH=7/7)Activating solutions which have significant difference with the other groups and also the control group. But fertilization, eyeing and hatching rate have not significant different with control group. Final conclusion confirmed that, the sperm activating solutions have positive and significant effects on extending the time length of sperms movement of Salmo caspius but there was no significant differencein surveyed items consist of fertilization, eyeing and hatching rates comparing with control group.