Prirodna hrana acipenser persicus gajenog u ribnjačkim jezerima

A study on live food in Acipenser persicus rearing ponds was carried out In four rearing ponds; two in the Shahid Beheshti hatchery and two ponds in the Yousefpour hatchery. Samples were collected from three points in each pond on a weekly basis. Samples were collected using plankton nets (mesh size 50 µm), Ruthner sampler and Ekman grab. Zooplankton and benthic samples were fixed in 4 % formalin solution for later analysis. Zooplankton species identified in water samples collected at all four ponds belonged mainly to two phyla; Arthropoda and Rotifera. Total abundance of zooplankton species was estimated 87576 individuals L-1 in the Yousefpour hatchery and 136626 individuals L-1 in the Shahid Beheshti hatchery. Insect larvae, oligochaeta worms and mollusks were found in the sediment samples collected from the Yousefpour hatchery while sediment samples collected from the Shahid Beheshti hatchery contained only insect larvae and oligochaeta worms. The total abundance of benthic organisms was 0.343 g m-2 in the Yousefpour hatchery and 1.28 g m-2 in the Shahid Beheshti hatchery. Condition factor in fishes ranged from 0.29-0.54 in the Yousefpour hatchery and from 0.30-0.47 in the Shahid Beheshti hatchery

The effects of glucan on hematological parameters, immune response and intestinal microbiota of Rutilus frisii kutum fry

The purpose of this study was to determine the effect of dietary glucan on some haematological parameters, immune response and intestinal microbiota of Rutilus frisii kutum. In the present study, various levels of ingredient so called Hoplit (0, 0.5, 1.0, 1.5, and 2.0%) containing glucan was added to a basal formulated diet. Twenty and five kutum fry with a mean (±SD) weight of 1.15±0.06g were stocked in each experimental tank (100 l capacity) filled with 80 liter of water. Fish were fed on experimental diet for 56 days and biometry was performed every 15 days. At the end of the trial blood samples were collected for measurement of haematological parameters including: Red and white blood cells count, differential count of white blood cells, hematocrit and hemoglobin, and innate immune factors (Immunoglobulin and Lysozyme). Fries in 1.5% treatment had highest serum immunoglobins (Ig) and eosinophil, although when compared with control but with no significant differences. Highest MCHC, hematocrit and hemoglobin were observed in the 0.5 and 1% treatments and the highest MCV and red blood cell count were in 0.5 percent treatment. The highest white blood cells count and neutrophils was observed in 2% treatment. The highest and lowest levels of lysozyme activity were observed in 1% and control treatments, respectively. Evaluation of the total bacteria and LAB counts revealed significant increase in 0.5% treatment. According to these results administration of dietary glucan can be considered for stimulation of innate immune response of white fish fry

Summer and winter feeding behavior in Acipenser persicus and Acipenser stellatus in the south Caspian Sea

Feeding behavior in Acipenser persicus and Acipenser stellatus in summer and winter was studied from 2004 to 2006 simultaneously with the marine survey for sturgeon stock assessment. Bottom trawls (9m) on board the research vessel Sisara 2 (50 hsp) were used to collect specimens at depth below 10m, while specimens at depths more than 10m were collected using bottom trawls (24.7m) on board the Guilan Research Vessel (1000 hsp). Examination of stomach contents of 135 A. persicus and 80 A. stellatus specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp., Clupeonella cultriventris), invertebrates belonging to the family Ampharitidae (polychaeta worms including Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.) and the bivalved mollusc, (Abra ovate). Significant differences were detected in the frequency of prey items in the different seasons studied. Also significant differences (P<0.05)