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In this study, 11 wild male brood fish were used and their mean ages were 15.08 ± 1.66. The luteinizing hormone‐releasing hormone analogue (LH‐RH‐A2) was used to stimulate twice in few days interval (3–7 days) and then semen samples were stripped. The results showed that there was significant difference among the percentage of motile spermatozoa, sperm density and spermatocrit during two strippings (< 0.05). The duration of sperm motility in first and second stripping was 315/83 ± 162.16 and 212.5 ± 110.53 s respectively. Also, sperm pH was 8.41 ± 0.53 and 8.05 ± 0.33 in first and second stripping respectively. There was significant differences between hatching rate, as well as larvae size significantly changed in both hatching and initiation of active feeding (< 0.05).  相似文献   
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Fish Physiology and Biochemistry - The aim of this study was to evaluate seasonal testicular development in the cultured sterlet, Acipenser ruthenus. During annual sexual cycle of male sterlet,...  相似文献   
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The aim of this study was to assess monthly testicular development in the cultured breeding stock of sterlet, Acipenser ruthenus, using histological and serum sex steroid changes. Testicular development in the adult male was examined monthly and showed four distinct phases including resting, pre‐spawning, spawning and post‐spawning. Also, seasonal changes of the testes were described according to its variations in gonadosomatic index (GSI) during different phases of testicular development. Using histology, we identified continuous spermatogenesis and asynchronous gonad development pattern in the testes of male sterlet, which shows that regulation of annual gonadal cycle is influenced by season. Results also showed variation in the GSI value and number of spermatogenic cells according to each season during annual cycle of gonad, as the highest value of GSI was recorded during spawning phase (spring; March‐May). Hormonal profiles of 11‐ketotestosterone (11‐KT) showed peak, which indicated a seasonal pattern of gonadal development. The 11‐KT concentration increased considerably during the spermatogenesis (pre‐spawning phase) and remained quite high throughout the pre‐spermiation period. In the final phase of testicular development (spawning phase), the 11‐KT markedly dropped. This study undertook an examination of complete reproductive development in cultured sterlet sturgeon to provide a valuable guide for the future sterlet studies, and allows comparison of reproductive development between sturgeon species.  相似文献   
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To determine the genetic relationship of Iranian viruses, the haemagglutinin (HA) genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 1998–2002 were amplified and sequenced. Sequence analysis and phylogenetic studies were conducted by comparing each isolate with those of the available H9N2 strains at GenBank. All these ten isolates had the same sequence –R-S-S-R/G-L– of proteolytic cleavage site of the HA. Nucleotide sequence comparisons of HA gene from Iranian isolates showed 95.2–99.1% identity within the group. Five isolates had leucine (L) at position 226 instead of glutamine (Q). Phylogenetic analysis showed that all our isolates belonged to the G1-like sublineage. Also these isolates showed some degree of homology with other H9N2 isolates e.g., 94.3–96.9% with qu/HK/G1/97, 96.1–98.6% with pa/Chiba/1/97, 95.6–98.2% with pa/Narita/92A/98, and 94.0–96.3% with HK/1073/99. On the basis of phylogenetic and molecular characterization evidence, we concluded that the H9N2 subtype influenza viruses circulating in chicken flocks in Iran since 1998–2002 had a common origin. The results of this study indicated that all Iranian viruses have the potential to emerge as highly pathogenic influenza virus, and considering the homology of these isolates with human H9N2 strains, it seems that the potential of these avian influenza isolates to infect human should not be overlooked.  相似文献   
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Motility is a key factor in function of the spermatozoon and determines semen quality and fertilizing capacity. Effective motility occurs when sperm is diluted in a swimming solution, the adequacy of which is determined by factors varying according to fish species. Spermatozoon motility rate and velocity, as well as duration of the motility period, are influenced by the temperature of the water in which broodfish are held. Increase in temperature of swimming medium beyond the optimal increases cell metabolism, leading to an increase in velocity with rapid depletion of energy resources, promoting early cessation of movement. The aim of this review was to discuss current information on the influence of temperature on quantitative spermatozoon properties, which could affect sperm function. Our findings provide a greater understanding of fish sperm physiology and a biological foundation for the further development of spermatozoon motility investigations as well as reproduction technologies.  相似文献   
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