فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال دوم شماره 2 (تابستان 1393)

Nonylphenol, a chemical widely utilized in the productuion of surfactants and pesticides, could interfere with the endocrine system of organisms. Large amount of this compound is released into the aquatic environments through industrial, agricultural and municipal effluents. The objective of the present study was to investigate the potential effects of a single-dose of nonylphenol at environmental level on the balance of thyroid and pituitary hormones of juvenile Caspian brown trout (Salmo trutta caspius). For this, fish with average weight of 40±10g was exposed for 21 days to a single concentration of 30µg/L nonylphenol and then, the plasma levels of thyroid (T3 and T4) and pituitary (TSH, FSH and GH) hormones, as well as GSI and HSI were studied in both male and female fish. The results showed that nonylphenol at environmentally relevant concentration had significant effects on the levels of GH, T3 and T4 hormones compared with control group. In addition, male and female fish showed different sensitivity in response to nonylphenol exposure. Regarding to the disruptive effects of environmental level of nonylphenol on juvenile Caspian trout, authorities must take necessary measures to prevent the entry of such chemicals into the Caspian Sea, as well as to protect the endangered fishes from mentioned chemicals, and to choose appropriate contaminant-free areas for releasing the fish.

Amylolytic enzymes are among the most important enzymes in food, pharmaceuticals, detergent industries and biotechnology. Alpha amylases cleave the linkage between adjacent glucose units in the linear amylose chain and ultimately generate glucose, maltose and maltotriose units. Although many microorganisms such as Bacillus licheniformis, Bacillus amyloliquifaciens produce this enzyme, Aspergillus niger as most popular one is used in industrial applications. In the present study, a strain of amylolitic Anoxybacillus sp. was identified. 16SrDNA analysis was carried out and bacterial optimal growth and production was investigated. Moreover, enzyme was partially purified and biochemical properties such as temperature, optimum pH and the effect of denaturants like SDS on the stability of enzyme were evaluated. On the other hand, encoded gene of enzyme was amplified and sequenced. Results indicated that after 20 hours, the optimal conditions for bacterial growth were at 60ºC and pH of 7. Also, maximum enzyme activity was obtained at 75ºC at pH 6 after 72 h of incubation. Enzyme showed higher optimum temperature but similar stability against SDS in comparison with other similar.

Benzo(a)pyrene (BaP) is an important compound of polycyclic aromatic hydrocarbons (PAHs) that is carcinogenic and very toxic. In this research, 45 pieces of common carp, Cyprinus carpio were divided to 2 BaP treated groups (those received 50 and 100 mg per Kg body weight) and a control group in 3 replicates for each group. BaP were injected intraperitoneally to evaluate its direct effects. Renal histological responses were examined at 24, 72 and 168 hours after exposing to toxicant. After 24 hours, more histopathological lesions were observed in 100 mg/Kg BW when compared with 50 mg/Kg and control groups. More lesions were observed in both 50 and 100 mg/Kg treatments in 72 up to 168 hours samples. Hypertrophy and hyperplasia of epithelial cells in Bowman's capsule, glomerular capillary aneurysm, epithelial lifting, tubular cell necrosis, and blood cell in Bowman's capsule were the most frequent observed alterations. There were significant differences between renal tubule diameters in different treatments and sampling times (P

Zona radiate (ZR) is an acellular region which during early stages of oocyte development appear outer to oolemma and attains more thickness and complexity by the action of follicular epithelium and oolemma itself. The structure of ZR might help in recognition of egg type, fish habitat, spawning ground and exchanging routs for needful gases and nutrients. Microscopic studies of histological sections of oviparous silver carp (Hypophthalmichthys molitrix) and viviparous molly (Poecilia sphenops) revealed that ZR in mature oocytes was a simple layer with vestigial pore canals. ZR in post-fertilized eggs showed reduction in thickness and possessed different appearance. Based on mode of reproduction, pre and post- fertilized egg of both species presented notable and expected differences in ZR thickness and architecture.

In present study common Klika from Guilan province coastal area (Bandar–e- Anzali) and fish meal produced from that, has been examined to investigate types and amount of Polycyclic aromatic hydrocarbons (PAHs). Bio-monitoring of pollutants is very important because they are carcinogenic and mutagen components, if they enter human food chain. Samples were collected from Anzali fishing port. 300Kg of fish sample sent to fish meal producing plant after fish containers were coded. 2 Kg of randomly selected sample was sent to laboratory for biometric analysis including fork length, weight and age determination by inner ear otolith method. For measuring PAHs, frozen samples were eventually taken to the laboratory and out of 16 PAH's compounds in EPA table for 3 year old fishes, 6 compounds were found namely: Naphthalen, Indeno (1,2,3…cd) pyrene, Pyrene, Fluorene, Anthracene and Dibanzo (ah) anthracene with quantity of 90.67, 19.75, 8.42, 5.93, 3.30 and 0.37 ppb respectively. In 5 years old fishes 74.00, 14.25 and 3.96 ppb Naphthalen, Indeno (1,2,3…cd) pyrene and Fluorene were determined respectively. While for 7 years old fishes no PHA has been found. For all age combinations 2 compounds i.e. Naphthalen and Indeno (1,2,3…cd) pyrene were present found with amount of 17.67 and 8.97 ppb respectively. In fish meal sample only Naphthalen and Indeno (1,2,3…cd) pyrene were recorded with amount of 11.73 and 5.98 ppb in order. The results also show that there is a significant difference between age increase and decline of Naphthalen, Pyrene, Indeno (1,2,3…cd) pyrene and Dibanzo (ah) anthracene. However there are no significances found between meal texture and produced meal in spite of decreasing trend. The results also showed that PAH amounts both in fresh Kilka and fish meal fortunately are below standard levels.

Environmental factors including salinity and temperature can affect the physiology and performance of fish growth. Therefore many of fish's internal organs such as kidney, show wide range of morphological and functional changes. In this study, histological changes of kidney tissue of common carp with average weight and length 38.28 ± 0.58 g and 14.04 ± 0.10 cm respectively is studied. Juvenile common carp were exposed for 21 days in groups at 20, 25 and 30°C and three salinity levels 0, 5 and 10ppt. After biometry, sampling was performed on 7th day and 21st day and then to the laboratory. The kidney was fixed in Bouin's solution for 24-48 hours and stained with Hematoxylin–Eosin. The results showed that glomerular size with high temperatures in the doublesampling significantly reduced and the maximum size of glomerular observed at 20°C (P0.05). There were significant differences between 20ºC to 25ºC and 30ºC (P0.05). Effect of salinity on glomerular number was (P>0.05) lower than that of temperature (P