Effect of Body Length on Haematological Parameters in Mylopharyngodon piceus

Sixty one grass carp( Mylopharyngodon piceus )(body length L ranges 9.4~30.7cm)were sampled and divided into 5 groups according to body length.Red blood cell number(RBC)，major axis，minor axis，area and serum hemoglobin content(Hb)were measured respectively.The results showed that the mean value of RBC was 2.33×109mL-1，major axis was 14.3μm，minor axis was 9.2μm，area was 96.1 μm2 and Hb was 83.77mgmL-1.It increased with the increasing L and the relationship between Hb and L can be described as Hb=1.47L+55.1(n=61，r2=0.307，p<0.01).RBC，major axis，minor axis and area did not change with the increasing body length.Both RBC and major axis were positively correlated with Hb (p<0.05)，while minor axis was negatively correlated with RBC (p<0.05).It indicates that the oxygen carrying capacity of blood of grass carp increases with the increasing body length.The number of the elliptical red blood cell tends to increase as Hb and RBC increases.