Weena Koeypudsa and Malinee Jongjareanjai

pp. 369 - 378

Abstract

This research was composed of 2 experiments. Short-term (1 day) and long-term (30 days) exposure were conducted
in the laboratory. Each experiment had 2 temperature levels, high (Ht, 29.5 ± 0.5°C) and low temperature (Lt, 19.5 ± 0.5°C).
Initial weight and length of catfish were 7.54±1.82 g and 9.90±0.96 cm respectively. Experimental catfish were subjected to 4
conditions as follows: high temperature with 0.1% sodium chloride (HtWs), high temperature without 0.1% sodium chloride
(HtW/s), low temperature with 0.1% sodium chloride (LtWs), and low temperature without 0.1% sodium chloride (LtW/s).
Blood was taken from caudal vessel of anaesthetized fish to investigate blood clotting time, cortisol, glucose, osmolarity,
Na⁺
, K⁺
 and Cl^-
. Ratios of Na⁺
/K⁺
, Na⁺
/Cl^-
 and Na⁺ + K⁺ / Cl^- were also analyzed. In the short-term (1 day) experiment, values of
all catfish blood parameters varied. These imply that catfish attempt to maintain internal balance, homeostasis. Osmolarity
exhibited complete homeostasis in 2 h. From long-term (30 days) exposure, non-significant means of Na⁺
/Cl^-
 ratio (HtWs)
and decreasing trend lines direction of blood clotting time (HtWs, LtW/s, LtWs) indicated that 0.1% sodium chloride and/or
Lt helped stress reduction in catfish. Sum of Na⁺ and K⁺
 to Cl^-
 ratio among 4 groups (HtW/s, HtWs, LtW/s, LtWs) revealed
that catfish spent 10 days for adjustment themselves under stress circumstance (HtWs, LtW/s, LtWs) to natural situation
(HtW/s). This information could be useful to improve the survival rate and health condition during rearing, handling and
transporting aquatic animals.