Abstract
In the present study, lysozyme, immunoglobulin M (IgM), and complement component 3 (C3) were measured in unfertilized and fertilized eggs, two week post fertilization (WPF) larvae and 1, 2, 4, 6, and 12 month post fertilization (MPF) juveniles and the female broodstock of Siberian sturgeon, Acipenser baerii Brandt. The lysozyme level was measured with the turbidimetric method and IgM and C3 levels were measured with the ELISA method. The results showed that the lysozyme level decreased significantly from the unfertilized eggs to the 2-week-old larvae, and then it increased until 2 MPF. Significant changes in lysozyme levels were not observed from the 2 MPF juveniles to the broodstock. The IgM level decreased significantly from the unfertilized eggs to the 2 WPF larvae, then it increased until the 2 MPF, and, finally, it revealed a significant decrease in 4 MPF juveniles. Significant variations of C3 were found from the unfertilized eggs to the 2 MPF juveniles. Additionally, there were no significant variations in IgM or C3 in 4 to 12 MPF juveniles or in the female broodstock. The results indicate that two weeks post fertilization can be an immunologically sensitive period in early life stages of Siberian sturgeon.