ABSTRACT
Background: Brownbanded Bamboo sharks [Chiloscyllium punctatum] is one of the cartilaginous fish that lives in the Persian Gulf
Objectives: The purpose of the present study is to study the effects of thyroid hormone on reproductive system of this specious
Methods: In this investigation, 36 individual of Brownbanded Bamboo sharks [Chiloscyllium punctatum] in both autumn [before reproduction] and spring [period of reproduction] seasons were caught from Dervish's Creek located at the northern of Persian Gulf. After weighing, biometry, sex determination and the numbering of sharks, [the sex is determined through clasper which is observed in male and not in female], ELISA was used to measure serum thyroid hormone concentrations
Results: The results showed that T3 and T4 hormones were increased dramatically in the reproductive season compared with the non-breeding season [p<0.05]. On the other hand, by classifying the sharks into different groups, we found that the levels of thyroid hormone were higher in the blood of larger sharks compared with the smaller ones [p<0.05]
Conclusions: It is probable that T4 hormone levels will increase dramatically for the development of eggs in the female shark
ABSTRACT
Bisphenol A [BPA], an industrially chemical compound, is abundantly used as a primary raw material for production of polycarbonate plastics, epoxy resins and many industrial productions. To show the effect of BPA on plasma steroid hormone variations, male Yellowfin seabream were subjected to this compound. Fish were intraperitonealy injected by dissolved BPA in coconut oil [10, 50, 100 and 150 microg/g-1 week-1] of over 2 weeks. Plasma samples were collected on days 0, 7 and 14. Plasma levels of steroid hormones [testosterone and 17beta-estradiol] were determined by radioimmunoassay. Plasma levels of 17beta-estradiol hormone in BPA treated fish was significantly increased in a dose dependent manner, after 7 and 14 days of exposure [p<0.05]. Plasma levels of testosterone showed decrease in response to different concentrations of BPA. However this decrease in testosterone levels was significant only in response to 100 and 150 micrograms per gram of BPA. It can be concluded that short term exposure of Yellowfin seabream [Acanthopagrus latus] to BPA can make destructive effects in reproductive system
ABSTRACT
Alterations to mitochondria-rich cells [MRC] in the fish gill epithelium have been previously reported. To specify the variation pattern of apical openings in mitochondria- rich cells in short and long terms exposure to different salinities. Yellowfin seabream, [Acanthopagrus latus] was subjected to different salinities [freshwater, 5, 20 and 60 ppt] besides the normal environmental salinity in the Musa creek [42 ppt] over 21days, with three replicates for each condition. Samples were collected at the 1[st], 7[th] and 21[st] days of experiment. Dissected gill arches were fixed in 2% glutaraldehyde+2% paraformaldehyde [pH=7.4] at 4°C and studied using scanning electron microscopy. Three subtypes of mitochondria-rich cells [shallow basin, deep hole and wavy convex] were detected in the gill epithelium based on different environmental salinities. While most of mitochondria-rich cells were present in seawater group, all of them were detected as the shallow basin subtype in 60 ppt group. Meanwhile, decrease in salinity to 20 ppt, made morphological changes in the apical membrane of the mitochondria-rich cells on day 7, so that most of these cells have been detected as wavy convex or shallow basin subtypes. On the other hand, on day 21 they showed a pattern similar to the basal status. Furthermore, when they were transferred to hypoosmotic medium [5 ppt and FW], rapid changes were exhibited in the apical membrane of mitochondria-rich cell which were stabilized after 21 days so that all subtypes of mitochondria-rich cells were observed in photomicrographs of gill filaments. Shallow basin mitochondria-rich cells as typical cells in seawater fish species, would be able to do osmoregulation in hyperosmotic environment in yellowfin seabream, yet in hypoosmotic conditions all sub- types of the mitochondria-rich cells would be required