Characterization of hematological parameters and blood cells of cultured Gymnocypris eckloni Herzenstein, 1891

The objective of the study was to obtain baseline data on haematological parameters, blood cell sizes and morphology in cultured male and female Gymnocypris eckloni Herzenstein, 1891. Forty-eight healthy 3-year-old G.eckloni (26 males: 525.79 +/- 48.56g weight, 34.51 +/- 1.88cm total length; 22 females: 507.60 +/- 54.48g weight, 33.97 +/- 1.84cm total length) were used for this study. Both male and female gonadal maturity were at stage III (maturing). The fish were reared in 25-36m(2) outdoor tanks at dissolved oxygen 6.86 +/- 0.48mgL(-1), pH 7.22 +/- 0.58, temperature 12.40 +/- 0.94 degrees C and stocking density 50-80 fishm(-3) during November 2014. The fish were fed commercial carp floating foods containing 35% crude protein three times daily. Haematological values were performed manually on heparin anticoagulated blood specimens using standard methods. The morphological features of blood cells and differential cell counts were done on Wright-Giemsa stained blood smears with no anticoagulants. Erythrocytes, leucocytes (neutrophils, eosinophils, lymphocytes and monocytes) and thrombocytes were distinguished and characterized under light microscope. The percentage of the different leukocytes revealed predominance of small lymphocytes (male: 62.31 +/- 2.06%; female: 63.00 +/- 2.25%) and nurophiles (male: 23.85 +/- 1.51%; female: 23.49 +/- 1.67%) followed by fewer monocytes (male: 4.81 +/- 0.68%; female: 4.80 +/- 0.77%) and few eosinophils (male: 3.73 +/- 0.82%; female: 3.52 +/- 0.67%). The nurophile percentages of each stage showed that metamyelocyte accounted for the most (male: 13.29 +/- 0.88%; female: 13.07 +/- 0.98%), followed by banded ones (male: 7.18 +/- 0.49%; female: 7.00 +/- 0.58%). The microstructure of G.eckloni blood cells was similar to that of other fish. Sex-dependent differences for the erythrocyte counts, haemoglobin, haematocrit and mean corpuscular haemoglobin were found (P<0.05 or P<0.01); while differences in other haematological parameters (P>0.05) and blood cell morphology between male and female fish were not significant. Hematologic parameters and knowledge of morphological characteristics of male and female G.eckloni blood cells could be utilized to evaluate the health status of this species in captivity.