عیسی شریف پور

Aquaculture development is challenged with limitation and high costs of supplying protein diets, so searching for alternative protein sources in fish diets is inevitable (Tacon, 2020). Insect meals are considered as a promising substitution protein ingredients last decades (Alfiko et al., 2022). Among candidates’ insect meals, Silkworm is well-balanced in protein as well as lipid and can be served as feedstuff (Mahanta et al., 2023). A study conducted to investigate if low level of silk worm pupa inclusion in fingerling Beluga sturgeon (Huso huso) diet could provide a protein source replacement accompanying with high benefit for the species.

Fingerling Beluga sturgeons (5±0.2 g, mean±SE) fed with experimental diets for a period of 8 weeks. Four experimental diets includes: no (SWP) inclusion as a control treatment (T0), 5, 10 and 15 percent (SWP) substitution referred as (T5, T10 and T15) treatments. At the end of the experiment, Weight Gain (WG), Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) calculated to assess the diets quality on fish production. Hepatic enzyme (ALP, AST, and ALT) and serum biochemical (IgM, total protein and lysozyme) analyzed for revealing the health status of fish.

(SWP) treatments, in particular (T15) had a significant increase in (WG) compared to the control group (p<0.05). (SGR) as well as (CF) in (SWP) treatments showed no significant differences compare to the (T0) (p<0.05). (FCR) was significantly improved among (SWP) treatments, although the difference was not significant (p<0.05). Serum lysozyme, Serum immunoglobin and total protein in (T10) and (T15) were significantly increased compared to the control group, (T0) (p<0.05).

Our findings indicate the protein level adjusts and fixes with the (SWP) was efficiently enough to be replaced with fish meal in fingerling Beluga sturgeon (H. huso). The results of (SGR) as well as (CF) suggest that the replacement level could be changes to more to get a differently improved result. Hepatic enzymes showed that (SWP) did not affect impairment in digestive tract.  What’s more, blood biochemical analysis showed that (SWP) can have immunomodulatory effects on fingerling Beluga sturgeons (Zhou et al., 2022)

This research was conducted in order to investigate the effect of adding salt and Bacillus subtilis bacteria (IS02) to the diet on the survival, cortisol response and antioxidant indices of sea carp, Cyprinus carpio, under salinity stress. Baby carp fish (average 1.1 g) were fed with diets containing 5 and 10% salt or 108 x 5.2 and 109 x 5.2 colony grams (cfu/g) of probiotics for 15 days and then to They were directly transferred to saline water with a concentration of 13 grams per liter and samples were taken after 3 and 10 days. Survival in all treatments was above 96%. The amount of cortisol at baseline and after salinity stress in probiotic treatments was significantly lower than other treatments. Superoxide dismutase activity was higher in probiotic treatments than other treatments. Diets had no significant effect on catalase activity. Based on the results of this research, the use of B. subtilis in the diet can reduce stress and increase the antioxidant capacity in juvenile Norse carp.

Since shrimp white spot virus has infected shrimps of all ages and caused widespread loss of shrimps in Iran and across the world, and the pandemic has caused great loss for shrimp farmers, many studies have been carried outto this day in order to identify the reasons and the risk factors regarding this fact. Regarding the importance of the subject and also the different opinions on the results of the past researches, in this study, we have tried to carry out a retrospective review on past studies in Iran and other countries especially on the target tissues for shrimp white spot virus in order to specify the tendency of the white spot virus generally. In this survey, the accomplished studies and researches in the Shrimp Research Center (Bushehr Province), other research centers, universities and higher education centers in Iran and other countries, were collected and the studies carried out on hepatopancreas, intestine, gill and other tissues were examined. Most of the target tissues for white spot virus in Penaeus vannameiwith high intensity are; hemolymph, posterior intestine epithelial cells and cephalothorax epidermis.Some researchers have claimed that the epithelium tissue is the most targeted tissue for white spot virus in penaeus vannamei. The lowest mean values of severity index (SI) were found to be from hemolymph, posterior intestine epithelial cells and cephalothorax epidermis. This could be due to more contact surface of the epidermis with the virus and also more receivers for the virus or lower operation of the immune system especially in horizontal transmission.It seems that hemolymph is the most probable early target tissue for the virus in vertical transmission because the virus replication is at a higher level compared to the other tissues.The most of researchers have pointed out in their researches that tissue of gill, stomach, hepatopancreas and intestine of shrimp are the most important tissues in relation to the white spot virus infection.

This study aimed to investigate the effect of salt (sodium chloride) supplementation in the diet on survival, biochemical indices, and tissue histology of juvenile wild common carp under salinity stress. Fish fry (approximately 1.1 g) were fed diets containing 0%, 5%, and 10% sodium chloride for 15 days, then directly transferred to brackish water (13 g/L) and sampled after 3 and 10 days. Diet or sampling time had no significant effect on survival and body moisture of fish. Sodium, glutathione reductase, and glutathione peroxidase levels in the body significantly increased three days after salinity stress, and returned to pre-stress levels after 10 days. Body moisture levels significantly decreased after salinity stress, but potassium and chloride levels in the body increased and remained significantly higher than pre-stress levels for up to 10 days. Prior to salinity stress, glutathione levels were higher in high salt treatment groups compared to control groups, and 10 days after salt stress, glutathione levels were higher in the 10% salt treatment group compared to the other two groups. Malondialdehyde in the body was significantly lower in sodium chloride treatments than the control. No significant and important histological lesions were found in the fish gill and kidney after salinity stress. This study suggests that wild carp fry can tolerate direct transfer to the Caspian Sea brackish water, without dietary sodium chloride supplementation. Dietary 10 g/kg salt supplementation decreases lipid peroxidation in the fish.

Due to the multifactorial etiology, tumor manifestation in any vertebrate species may become a critical issue. This topic requires more consideration for species in aquatic ecosystems as an enclosed habitat. In addition, knowledge about oncogenesis in the aquaculture industry enhances the quality of products and its earned benefits.

This study investigated the tumor lesions, their characteristics, and probable causes, in the most commercially important fish in the southern Caspian Sea: Caspian white fish (Rutilus kutum). 

To accomplish this goal, after gross pathology of more than 20 cases, histopathological examinations and electron microscopic assays were employed.  

The findings confirmed squamous cell carcinoma and squamous cell papilloma in the examined cases. Furthermore, the virus-like particles were clearly observed in the transmission electron microscopy results, indicating the probable viral etiology for these neoplastic lesions in Caspian Kutum. 

This study is the first to report the tumor prevalence in fish species of the southern Caspian Sea, which could be an alert for the mentioned ecosystem’s health and the whole aquaculture industry.

This study was conducted to investigate the effect of adding Bacillus subtilis (IS02) to the diet on survival, biochemical indices, and histological alternations of juvenile wild common carp, Cyprinus carpio, exposed to salinity stress. Juvenile common carp (about 1.1 g) were fed diets containing 0 (control), 2.5 × 108 (pro-8), and 2.5 × 109 (pro-9) cfu/g probiotic for 15 days and then transferred directly to brackish water (13 g/L) and sampled after 3 and 10 days. Diet and sampling time had no significant effect on fish survival, which was above 96% in all treatments. Body moisture and potassium were only affected by sampling time, with moisture decreasing significantly after salinity stress while potassium increased significantly. Whole body sodium in pro-8 treatment did not change significantly during salinity stress, and probiotic treatments had lower chloride levels than the control before and after salinity stress. Adding probiotic to the diet increased glutathione reductase, glutathione peroxidase activity, and reduced glutathione concentration, while decreasing malondialdehyde concentration. Probiotics caused white blood cells infiltration in the kidney tissue. No significant tissue damage was observed in the gill and kidney, compared to the control after salinity stress. This study shows that juvenile wild common carp can tolerate direct transfer to the Caspian Sea without dietary probiotic supplementation. However, probiotic stimulates the kidney immunity, enhances ionoregulation, and increase antioxidant capacity in fish, which can have beneficial effects under field conditions.

This study was conducted from April 2017 to June 2018 in a Trout aquaculture farm in Firoozkoh, Tehran province, to distinguish environmental and managerial risk factors affecting incidence of viral diseases in the fish farm under study. Averaged visit from fish farm was 2 times a month and all biosecurity measures were advised and applied during every visit. Some of the physico-chemical parameters were recorded daily. Samples from all cargoes of eyed-eggs imported from abroad and also from larvae after active swimming and absorption of yolk sac were taken for RT-PCR test. Virology, bacteriology, parasitology and mycology tests in the farm and authorized laboratory were done. Clinical observations, macroscopic and microscopic examinations, checking all the sanitarian and productional managerial factors, also checking all the physical and chemical factors affecting the outbreak of viral diseases were done. During clinical observation of fishes, these symptoms were observed; anorexia, gathering at the raceway’s side and outlet, cachexia, one and two side exophthalmia, melanosis, integument ulcers, hemorrhage in ventricular and ocular areas, petechia in ventricular area, fecal casts, high mortality and also presence of a large number of moribund fishes. The result of the laboratory examinations was IHN positive of Rainbow trout fries. This disease caused about 80% mortality of the fries produced from the imported eyed-eggs cargo. The other fatalities with different reasons were also recorded such as; the Lutra’s attack at nights, the farm’s personnel running amongst other farms and transferrin pathogens, the transportation vehicles not being proper disinfected while inter to and exit from the farm and the severe food intoxication of fries. Regarding the results of this study, instruction of scientific and practical models has presented to decrease the effect of environmental and managerial risk factors in the incidence of the disease.

MTBE increases oxygen consumption as well as reducing carbon monoxide and air pollution. It is very dynamic in soil, and its movement in water is a function of water movement in soil. MTBE is resistant to biodegradation, its half-life in water is long, its absorption in soil particles is weak, having high solubility in water, and being very dynamic. This research was aimed at investigating DNA blood cells of Rutilus caspicus in concentrations of 50, 100 and 150 mg/L MTBE for 7, 14 and 21 days. The mean temperature of water was 19 ± 1°C, water oxygen was 7.6 ± 0.2 mg/l, and salinity was considered zero. 220 R. caspicus with an average body length of 150 ± 30 mm and a weight of 15 ± 3 grams were prepared from Sijawal multiplication workshop located at the Turkmen port in Golestan Province and transferred to the laboratory by means of bags containing water (1/3) and oxygen (2/3). After the adaptation period, 13 fish were placed in 50-liter aquariums. The total number of control aquariums was three, and the number of treatment aquariums was nine. In the first, second and third weeks of the test, three fish were randomly taken from each aquarium and their blood samples were collected. After performing the determined stages, the blood samples of the fish were fixed on the slide and kept in the refrigerator for observation with a fluorescence microscope. In this study, Casp 1.2.3b1 software was used to evaluate the DNA degradation. In this software, several examples of alkaline comet data are extracted in data form. The results of this study showed that there was a significant difference between the control and other treatments in terms of DNA degradation. Furthermore, with increasing exposure time, the amount of DNA damage significantly increased (p < 0.01).

white spot disease (WSD) in shrimps causes heavy losses in shrimp farming in the country. Various studies have reported different physical and chemical factors in water for WSD incidence. The purpose of this study was to determine the rate of studied risk factors in WSD incidence in shrimp culture farms in West Bahu Kalat (Southeastern Iran) by logistic regression model.

Some factors in water such as: temperature, salinity, oxygen, pH, ammonia, silica, transparency and the amount of phytoplankton and some management factors from 12 pounds of shrimp culture farms located in Sistan and Baluchestan province during two years (2010 and 2011) were measured and recorded. 1180 cultured Litopenaeus vannamei from 12 pounds were tested for identification of the white spot virus (WSV) by Nested-PCR method.

The data analysis with software (PASW Statistics 18, SPSS) showed effects of oxygen, temperature and transparency factors in incidence of WSD in the studied area.

Some risk factors were more importance than others and some risk factors had not affected the incidence of WSD in this study. It seems that WSD incidence related to some ecology of studied area and biologic of host factors are not measured in this study.