Study on effects of extracted probiotics from microbial flora of digestive system on growth indices in beluga (Huso huso) and Persian sturgeon (Acipenser persicus)

Isolation of Lactic Acid Bacteria (LAB) was carried out from gastro intestinal tract of beluga and Persian sturgeon at international sturgeon research institute and PCR has been used for bacteria Identification. Two species of LAB including Enterococcus seriolicida and Leuconostoc mesenteroides were isolated from Gastrointestinal tract (GI) of persian sturgeon in this study and the counts of Leu. mesenteroides (4.63×102 CFU/gr of GI) was significantly higher than other species. Lactobacillus curvatus, Lactococcus raffinolactis, Lactococcus lactis and Streptococcus sp. were also isolated from GI of beluga and maximum counts was belonged to Lb. curvatus (4.63×102 CFU/gr of GI) in this species. Dominant species were lyophilized and adding to the water since start of mix feeding of sturgeon with different counts including 2×109, 5×109 and 9×109 CFU/gr of live food, 4 times a day. The results revealed that the maximum and minimum growth rate and protease, amylase, and lipase activity in beluga was gained by using of Lb. curvatus with total viable count of 9×10 9 CFU/gr of live food and Leu. mesenteroides with total viable count of 9×109 CFU/gr of live food. According to the results of this study, the maximum and minimum growth rate and protease, amylase, and lipase activity in Persian sturgeon was gained by using of Leu. mesenteroides with total viable count of 2×10 9 CFU/gr of live food and Lb. curvatus with total viable count of 9×109 CFU/gr of live food. Histological study showed that gastrointestinal development was same during larva rearing in control and other treatments but the size of liver was bigger in treatments that received nonspecific LAB in both species. According to the results, positive effects of using dominant specific LAB bacteria for larviculture of sturgeon has been proved in this study.

Circulation system and areas of potentially successful tuna fishing with surface methods off Mozambique

Charts with 3-months running means of thermal data collected during 1977-1982 are used to describe the seasonal variability of the circulation pattern off Mozambique, and to identify the areas of tuna vulnerability to surface gears. The main conclusions reached by Sætre and Jorge da Silva (1984) have received further support. Areas of potentially successful exploitation of tunas by surface methods have been identified during the whole year, with emphasis for November-April.

Survival, growth and production of Penaeus monodon at different stocking densities in earthen ponds with flow-through system and supplementary feeding

The survival, growth and production of Penaeus monodon in earthen ponds were observed. A significant effect of stocking density on the survival rate of prawns was observed. The final average weight obtained varied inversly with the stocking density and the production varied directly with stocking density and survival rates. The maintenance of a clear water environment is recommended as a preventive measure against Vorticella attack.

The first quarter survey of the aquatic system and fisheries of the upper Victoria Nile, 6th -13th April 2006

The purpose of this present study therefore is to provide and update the AES Nile Power EIA baseline information on the ecology of the river ecosystem prior to the construction of the dam. The study is intended to provide a basis for evaluating the impact of the project on the river environment, the biological resources associated with it and fisheries socia-economics and the vector/sanitation status. This report presents the findings of the first sampling regime which was conducted between the dates of 6th-13th April 2006 and compared with the AESNP Environmental Impact Assessment findings of the second quarter carried out during 5th-14th April 2000.

Effects of atrazine herbicide on physiological, biochemical and histological biomarkers of developmental stages of larvae and fry in Caspian kutum, Rutilus frisii kutum

To investigation of the toxic effects of atrazine on newly hatched larvae and releasing age fry of the Caspian Kutum, Rutilus frisii kutum, the 96h LC50 was determined as 18.53 ppm and 24.95 ppm, respectively. Newly hatched larvae were exposed to three sublethal concentrations of atrazine (1/2LC50, 1/4LC50 and 1/8LC50) for 7 days. Different histopathological alterations were observed in fins and integument, gills, Kidney, digestive system, liver and the brain of the exposed larvae. Fry’s were exposed to one sublethal concentration of atrazine (1/2LC50) for four days, and like the larvae’s, many histopathological alterations were observed in fins and integument, gills, Kidney, digestive system, liver and the brain of the exposed fry’s, too. Also, measurements of the body ions: Na+, K+, Ca2+, Mg2+ and Cl- in atrazine exposed larvae and fry’s compare to control groups showed that atrazine is changed the body ions composition. No significant differences were found in length growth rate, weight growth rate and the condition factor of the atrazine exposed larvae and fry. Immunohistochemical localization of the Na+, K+-ATPase in integumentary and gill ionocytes, showed no differences in dispersion pattern of the ionocytes in atrazine exposed larvae and fry, compare to control group. Measuring the dimensions of the ionocytes and counting the ionocytes showed that atrazine is affecting on ionocytes by mild increasing in size and mild decreasing in number. Ultrastructural studies, using SEM and TEM, showed that atrazine have significant effects on cellular and subcellular properties. It caused necrosis in surface of the pavement cells in branchial epithelium, necrosis in endoplasmic reticulum of the ionocytes and changed the shape of the mitochondria in these cells. Results showed that sublethal concentrations of atrazine were very toxic to larvae and fry of the Rutilus frisii kutum, and at these levels can made some serious histopathological alterations in their tissues. Related to the severe histopathological alterations in osmoregulatory organs, like gill, kidney and digestive system, and the alterations in the body ion composition, it could be concluded that atrazine could interfere with the osmoregulation process of the Rutilus frisii kutum at the early stages of the life history.

Study of the ecophysiological stress effects on HPG and HPI axes, immunity system and reproduction processes in Persian sturgeon (Acipenser persicus)

The ecophysiological effects of stress in female Persian sturgeon, Acipenser persicus brood fishes during catch, transport and their confinement in the Kurenski ponds at the Shahid Dr. Beheshti Fish Propagation and Rearing Center were studied. The brood fishes under study were caught at three catch stations located at the Sefidrud River, Sefidrud River estuary and Gorganrud River estuary and were held in ponds at the Shahid Marjani Fish Propagation and Rearing Center.