Investigation of the process of changes in blood, immunity, ions, testicular tissue and hormonal tissue of whitefish and its relationship with fish age (Rutilus kutum) in winter and spring seasons of Chaf and Wahmakhaleh of Guilan province

The purpose of this study was to investigate the changes in blood, immunity, ions, testicular histology and white blood cells and its relationship with fish age (Rutilus kutum) in winter and spring seasons of Chaf and Chamakhaleh of Guilan province from February 2016 to May 2017 in Chamkhaleh and the correlation between fish age and hormones was also determined. In order to carry out the present research, 30 live fish were taken.  Blood samples were collected to measure blood factors (white and red blood cells, hemoglobin, hematocrit), (IgM and lysozyme), ions (calcium, sodium, potassium and magnesium) and hormones (estradiol and progesterone). The tissue sections were also collected from the testicles. Fish scales were also sampled to determine age. The results of this study indicated that the amount of hormones examined was consistent with the development of the testicle. Also, there was a significant difference in the level of hormones in some sampling months in this area and the highest levels of progesterone and estradiol in the Chamkhala region were observed in the fishes of 5 and 4 years old (Progesterone Chamkhala, 0.33 ± 0.02 and Chaf 0.31 ± 0.01 in May). The level of progesterone hormone changes significantly during the months and reached the highest level in May (P <0.05), but estradiol levels increased from February to February (P<0.05) and remained high until May. (0.9 ± 0.2) The amount of ions in March or February was lowered, and their levels reached the lowest levels in May. Calcium was 12.5 ± 0.08, magnesium was 5.8 ± 0.15, 145 ± 2 and potassium 8.0 ± 0.05, 0 (P <0.05). The level of some blood factors (including the number of white and red blood cells, hemoglobin and hematocrit) in the final stages of sexual maturation increased significantly. Red blood cells of the blood were 100000 ± 1850000, white blood cells of 6150 ± 350, hemoglobin of 11.85 ± 0.055, hematocrit of 58.6 ± 3.5 (P<0.05), but the levels of lysozyme and Igm in the month of May were at the lowest level, lysozyme 2 ± 23 and Igm ± 1 ± 26 (P<0.05). Regarding the serum IgM levels of the Rutilus kutum  during the months of Febuary to May, there were no significant differences in Chaf and Chamkhaleh regions, and it was almost constant. The various stages of sexual maturation during the months leading up to the development of the testis did not affect the change in this factor.