Effects of temperature and gonadal growth on the lysozyme level of immune tissues in the male and female Caspian kutum (Rutilus frisii kutum)

Lysozyme levels in the head kidney, spleen and liver tissues of the male and female Caspian kutum (Rutilus frisii kutum) were measured under monthly temperature variations and gonadal growth. The lysozyme content in all tissues of the male and female of the Caspian kutum showed almost a significant decreasing trend from October to March, coinciding with the lowest sea surface temperature and afterwards, it increased in April and May. In vitellogenic stage of the ovarian growth, the lysozyme level decreased in all three tissues and then increased significantly in the spawning stage. Over testicular growth, lysozyme level showed no remarkable variations from the early maturing to developed stages but increased in the spermiation stage. The regularity of lysozyme level in both sexes of the Caspian kutum was liver>spleen>head kidney. The effectiveness ratio (partial Eta(2)) of temperature and gonadal growth in the lysozyme variations showed that temperature factor was more highlight than gonadal growth. In conclusion, the liver similar to the kidney and spleen plays an essential role against pathogen as an organ of lysozyme producing in the Caspian kutum. In addition, the female lysozyme level was higher than the male in all studied tissues.