Article info.

ABSTRACT

Received 07 Aug 2017
Revised 06 Nov 2017

Accepted 09 Mar 2018

Physiological responses and growth of clown knifefish (Chitala ornata) (initial weight of 11-12 g) exposed to nitrite were investigated with two separate experiments. The first experiment examined the effects of different nitrite concentrations on haematological parameters. The second experiment examined the effects of different nitrite concentrations on fish growth including 4 treatments such as control, 0.2 mM nitrite, 0.4 mM nitrite, and 4 mM nitrite for measuring growth parameters at days 0, 30, 60, and 90 (sampling 30 fish/tank). There were significant increases in methaemoglobin and leukocytes while other haematological parameters decreased during nitrite exposures at the treatment of 4 mM nitrite. Particularly, methaemoglobin and the number of leukocytes increased from 0.4 to 29.5% and from 39.89x103 to 72.33x103 cells/mm3, respectively. Differently, there were significant declines in the number of erythrocyte (3.19x106–2.33x106 cells/mm3), haemoglobin (10.47-7.04 mM), and haematocrit (38.07-26.5%) at the highest nitrite treatment. After 90 days, daily weight gain (0.25±0.02 g/day), specific growth rate (1.18±0.07 %/day), survival rate (59%) at the treatment of 4 mM nitrite were significantly lower than those of the control, but no significant difference was observed in such parameters between the control and the treatments of 0.2 or 0.4 mM nitrite.

Keywords

Clown knifefish, growth, haematological parameters, nitrite

Cited as: Gam, L.T.H., Vu, N.T.T., Nhu, P.N., Phuong, N.T. and Huong, D.T.T., 2018. Effects of nitrite exposure on haematological parameters and growth in clown knifefish (Chitala ornata, Gray 1831). Can Tho University Journal of Science. 54(2): 1-8.