Iranian Journal of Fisheries Sciences
Year:2006 | Volume:5 | Issue:2|Papers Count:7

Some biological aspects of semen were investigated in the Persian sturgeon, Acipenser persicus, by determination of seminal plasma indices (ionic composition and osmolality), sperm density and their relationships with sperm motility. The osmolality of seminal plasma ranged from 42.00 to 111.00 mOsmol Kg-1. The concentrations of Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca2+) and Magnesium (Mg2+) ions were 62.44±6.82, 6.92±0.88, 21.11±5.41, 0.79± 0.03 and 0.52±0.03mM L-1, respectively. The sperm density was 8.34±1.38×109 spz/ml.  The Sodium/Potassium and Calcium/Potassium ratios were 9.02 and 0.13, respectively. The following significant positive correlations were found between seminal plasma indices; osmolality - Cl- (r2= 0.492, P<0.05), osmolality - Na+ (r2= 0.905, P<0.001) and Na+ - Cl- (r2= 0.584, P<0.05). There were also no significant correlations between ionic composition and osmolality of the seminal plasma and sperm motility (P>0.05).  No relationship was observed between sperm density and its motility at the concentrations tested (r2= 0.015, P>0.05). The ionic composition and osmolality of seminal plasma reveals an inter-species specific as well high secretory activity of sperm duct. The clear differences observed in A. persicus should be considered when cryopreservation methods for sperm are developed in Acipenseridae species.

This study was carried out to find any relative concentrations of the trace metals (Cu, Cd, Zn and Pb) in the liver and the kidney of Acipenser persicus and in the surficial sediments of the west coast of The Southern Caspian Sea. Twenty five samples of the Acipenser persicus (Persian sturgeon) and ten samples of the sediments were taken from five fishing stations in autumn 2001. The tissues were digested by wet method and the sediments were digested by dry method. Every digested sample was separately analysed by AAS (Atomic Absorption Spectroscopy). Recovery, mean, ANOVA, correlation coefficient and hierarchical cluster analysis were calculated. It was concluded that the concentrations of the studied trace metals (Cu, Cd, Zn and Pb) were at the standard level and there was a positive correlation coefficient between the kidney and the liver in the concentrations of Cd and Pb.

Phenoloxidase (Po) activity was measusred spectrophotometrically in serum, plasma and haemocytes (HLS) of the freshwater crayfish (Pontastacus leptodactylus). The highest activity was found in HLS suggesting that the haemocytes are the major source of the Po or its proform prophenoloxidase (proPO) in crayfish. Furthermore, the enzyme activity in serum samples was reduced after freezing the samples for 20 days at -20˚C. Po activity was cation-dependent and the peak of enzyme activity obtained using 5mM of CaCl2 or MgCl2 .Also, the Po activity in the HLS samples treated with different elicitors of 10% sodium dodecyl sulphate (10%SDS), b 1-3-glucan, Aeromonas hydrophila lipopolysaccharids (LPS) and trypsin resulted in variable activities with the highest and the lowest activities measured in samples treated with trypsin and 10% SDS, respectively. The marked enhancement induced by trypsin suggest the role of an endogenous proteinase which is probably able to promote the enzyme activity. To confirm the role of the proteinase on the proPO activating system, trypsin activity was also measured in the crayfish HLS.

Hematological and biochemical changes were studied in beluga (Huso huso) weighing 450±50g in the presence of  b,1-3, D-glucan as a single intraperitoneal injection (0.3mg/kg body weight) once, and thereafter a chronic exposure to organophosphate, diazinon at concentration of 1.5 mg/L as a continuous bath for 63 days at 22±1ºC. Results of erythrocyte profile in fish treated with glucan, but without diazinon, generally showed significant higher values of RBC (P<0.05) compare to fish treated with glucan plus diazinon bath, while there was no significant difference (P>0.05) in the values of HCT, Hb, MCH and MCHC between the two groups. Also, fish treated with glucan, but without diazinon bath, showed significant higher values of RBC than that untreated fish up to 3 weeks post-treatment (P<0.05), while no significant differences was found in other erythrocytic indices between these two groups (P>0.05). Furthermore, fish treated with diazinon showed higher levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) than other three groups for 14-28 days post-treatment and then they decreased to the lower level for the rest of experiment. Also, fish treated with glucan-diazinon showed insignificant higher levels of these enzymes up to 21 days post-exposure compare to fish treated with glucan but without diazinon bath (P>0.05). However, such levels reduced to a lower level in this group for the rest of experiment (P>0.05). Also, fish treated with glucan-diazinon showed generally lower  and higher levels of total protein and glucose concentrations in blood plasma, respectively  compared to fish treated with glucan but without diazinon bath (P<0.05).

Toxicity of the organophosphate, diazinon was studied in grass carp (Cetenopharyngodon idella) weighing 5±1.0g, under static water quality condition at 16°C. Also, some hematological and biochemical variables of fish weighing 50±5.0g were studied 12 hours post-exposing fish to the toxicant at sublethal concentration of 5.6mg/L at 16°C. Values of 18.19, 17.21, 16.68, and 15.13mg/L, were obtained as LC50 after 24, 48, 72 and 96 hours post-exposing fish to the toxicant, respectively. Levels of red blood cells (RBC), hematocrit (PCV), hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), leukocyte count (WBC), lymphocyte and monocyte were significantly lower in the exposed fish than control fish (p<0.05), whilst values of polymorphonuclear cells (PMN) and myelocytes counts were higher in the test group (p<0.05). In addition, the levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were significantly lower in fish exposed to the toxicant (p<0.05), while the level of alanine aminotransferase (ALT) was higher in experimental fish (p<0.05) than control fish. The levels of glucose and triglyceride were higher in fish exposed to toxicant than control fish. However, such differences were only significant for glucose level (p<0.05). In contrast, the levels of total protein and cholesterol decreased insignificantly in fish exposed to the toxicant compared to those in control fish (p>0.05). The obtained results show that although diazinon can be classified as a slight toxic chemical for grass carp, the toxicant negatively affects some immunophysiological functions of the fish including immunocompent cells.

In Iran, carp is widely sold and used in its fresh, although a range of added value products may also be observed. The common carp and the three Chinese species are often reared in polyculture ponds. Since, the 1970S carp farming has spread along the Caspian Sea coasts, followed by other provinces, and farmed production reached a peak in 2004 with production of more than 60,000 tonnes. Rapid expansion of carp cultivation has been followed by marketing problems in recent years. Consumer and market-related data to develop effective marketing strategies are essential to the growth of the carp farming industry in Iran. A questionnaire was prepared concerning personal information of re-spondents and their preferences for carp consumption. A face to face interview was carried out with 357 individuals randomly selected in Tehran province. Due to the comparatively small sample size of interviews, to obtain qualitative data, complementary study was also conducted using an unstructured questionnaire. Results showed younger group preferred ready meal and demanded for a variety of products. It was found, to increase carp consumption a rise in income and decline in price of carp products will affect older groups, larger family size and educated people. The study also showed a significant difference between locations and consumption behaviour (which related to socioeconomic, different aspects such as income, educational level, job and family status) this difference may be expected to affect seasonality of consumption. It seems increases a variety of product in markets, a rise in income and price decline may increase all year round fish consumption.

Histopathological effects of different sublethal concentrations (1, 2 and 4 mg/l) of diazinon, an organophosphorus pesticide, on gill, liver, spleen and kidney of grass carp (Ctenopharyngodon idella) were studied after 1, 7, 15, 30 and 45 days post-exposing fishes weighting 850 ± 155 g to the toxicant for 12 hours at 18-22ºC. In addition, tissues of nostril were examined for transmission electron microscopy and scanning electron microscopy. Results of light microscopic examinations of tissues showed that toxicant was causing severe histopathological effects such as congestion of blood vessels, haemorrhage, cellular infiltration, pyknosis of cells nuclei, vacuolar degeneration and general necrosis in the kidney, spleen and liver. There were also degenerative changes of interstitial tissue and detachment of tubular basement membrane in kidney observed. Hyperplasia and fusion of secondary lamellae, separation and sloughing of epithelium from the underlying basement membrane were also observed in gill sections. transmission electron microscopy (TEM) examination of nostril revealed, damages of epithelial cells (vacuolated club cells and abnormality in cells' nuclei). scanning electron microscopy (SEM) examination of nostril showed a reduction in excretion of amorphous proteinous materials, reduction in vesicle numbers on the cell surface and also closing of cell surface canals.