E. Salamroodi , K. Rezaei Tavabe, S. Javanmardi,
Volume 8, Issue 1 (3-2019)
Abstract
Aims: Malathion is one of the agricultural organophosphate pesticides used in agriculture that may be found in aquaculture centers. The aim of this study was to investigate the effects of different levels of dietary vitamin C on improving the situation of growth, digestive enzymes activity and blood stress factors of Nile Tilapia (Oreochromis Niloticus) under sub-lethal toxicity of malathion.
Materials & Methods: In this experimental study, 180 Nile tilapia with weight average of 12.5±5g were subjected to 25% concentrations of Lc50 96h of malathion for 28 days and during this period, the fishes were fed with different levels of vitamin C (0, 300, 600, and 900mg/kg of feed). Data were analyzed by Duncan's new multiple range test and one-way analysis of variance through SPSS 24 software.
Findings: The weight gain and specific growth rate of fish fed by the highest vitamin level (900mg/kg of feed) were significantly higher than other groups (p<0.05), while the feed conversion ratio in the fish under mentioned treatment significantly decreased compared to other treatments. Trypsin and chymotrypsin digestive enzyme activities were significantly increased in treatments of 600 and 900mg/kg vitamin C in diet, respectively. The activity of other enzymes at different concentrations of vitamin C in the diet did not show a significant difference (p>0.05). Blood glucose level was significantly higher in control treatment in comparison to the other treatments.
Conclusion: Vitamin C as an anti-stress agent reduces the stress in Nile tilapia subjected by Malathion pesticides and improve the metabolic status and growth performance of Nile tilapia.
Omid Shayanfar, Mehdi Ghodrati Shojaei, Siamak Behzadi,
Volume 12, Issue 2 (4-2023)
Abstract
The purpose of this research is to investigate the relative importance of Avicennia marina organic matter in the feeding of Ilisha melastoma fish in the Mangrove Biosphere Reserve; It was stable isotope approach. Three primary food sources including mangrove tree leaves, microphytobenthos and suspended organic particles were analyzed isotopically. The samples of primary food sources and fish are converted into pure and simple gases such as CO, CO2 and N2 after minimizing the size and turning into powder. Then the identified isotope ratios are compared with a measured standard and the exact amount of isotope formed in the sample is obtained. In this research, sampling was done seasonally in August in the summer season and February in the winter season of 2019 in the mangrove ecosystems of Bandar Khmer, Hormozgan province.In the summer season, the average stable carbon isotope of primary food sources fluctuated from -28.07 units per thousand for mangrove leaves to -13.58 units per thousand for microphytobenthos.This average in the winter season was obtained from -28.05 units per thousand for mangrove leaves to -13.54 units per thousand for microphytobenthos.The average stable nitrogen isotope of primary food sources in the summer season fluctuated from 1.44 units per thousand for microphytobenthos to 10.72 units per thousand for suspended organic particles.The results of this research showed that in the summer season, suspended organic particles with 63% and in the winter season, microphytobenthos with 45% play the most important role in providing the food needed by the small shemsk fish.
Mohammad Darvishi, Mohammad Momeni, Siamak Behzadi, Ali Salarpouri, Shiva Aghajari Khazaei,
Volume 12, Issue 4 (12-2023)
Abstract
Trichiurus lepturus is one of the most important and commericial species in the Persian Gulf and Oman Sea.In order to come up with the responsible fishing pattern,there was a need to identify reproduction characteristics. Data were collected randomly from April 2019 to February 2020 from six major artisanal fish-landing sites in Hormuzgan Province (Bandar Parsian, Bandar Kong, Qeshm Island, Bandar Abbas, Bandar Sirik and Bandar Jask). In the detection of sexual stages, the 5-stage key of sexual maturity was used at the macroscopic level. In determining the spawning season, the gonado-somatic index(GSI) was used and its comparison in different months. The lowest GSI of female fish was in September (1.2). The highest GSI of male fish was determined in December with a value of 3.1 and after that in May 2.6. Examination of the GSI and reproductive stages showed two main spawning periods in the middle of spring and late autumn. Different sexual stages were seen in all months of the year, which indicated the batch spawning strategy in T. lepturus. During different months, significant differences in the sex ratio were observed, but during the investigation and in total, no significant difference was observed between the female: male sex ratio in the expected ratio of 1:1.The length at first maturity obtained 78.7 cm total length. It is necessary to ban fishing during the spawning season in order to protect the stocks of this species.
Mona Riyazi, Mohammad Reza Taherizadeh, Maryam Salimizadeh,
Volume 13, Issue 1 (1-2024)
Abstract
Gobiidae family fishes play a significant role in coastal ecosystems with mud beds and mangrove ecosystems and also play a key role in the food chain in these areas. They are known as a heavy metal biomarkers. The aim of this study was to investigate the metals cadmium, lead and nickel in the muscle of two species including Cryptocentrus cyanotaenia in Hormoz Island and Boleophthalmus dussumieri in the Bandar Kamir. A total number of 30 fishes, samples for each species were collected from selected area and after biometrics and preparation and digestion steps to determine the concentration of nickel, cadmium and lead metals were analyzed by atomic absorption spectrometry. In this study, comparisons were made between the concentration of metals with a maximum of 13.10±1.88 and a minimum of 2.85±1.20 µg/g, respectively for lead and cadmium in the muscle of B. dussumieri. The highest and lowest values of 12.13±1.96 and 2.86±0.83 respectively were recorded for lead and cadmium in C. cyanotaenia muscle. By examining the correlation between the concentrations of metals in the muscle of the species, it was found that there is a positive and significant relationship between the concentration of metals in the muscle and their biometry (total length and total weight). The results showed that the studied Gobiidae family fish are suitable biomarkers for nickel, cadmium and lead metals.
