Abstract:
Koi (Cyprinus carpio) is one of the most popular temperate ornamental fish species.
Growth of the Koi trade in Sri Lanka is hindered by poor packing strategies and
mortalities during transport. Therefore, the study aimed at evaluating the anesthetic
efficacy of Clove oil, Benzocaine, and MS-222 in simulated long transportation
conditions on Koi. 75 d old Koi with standard length (6.025 ± 0.04 cm) and weight (6.153
± 0.23 g) were selected for the experiments. These individuals were subjected to four
different dosages of anesthetics, based on the results obtained at the range-finding test.
Each sample consists of 10 individuals and dosages were triplicated. Samples were
exposed to simulated transportation conditions for 10, 20, 30, 40 h, and effective dose for
each anesthetic was determined by assessing the Sedation Induction Time (SIT),
Recovery Achievement Time (RAT), Mortality Rate and Post-exposure Survival Rate of
Koi. Changes in water quality parameters including pH, ammoniacal nitrogen, and
dissolved oxygen in transport water were recorded. Results obtained were analyzed using
one-way ANOVA followed by Tukey's’ method and General MANOVA using Minitab
17.0 version (p< 0.05). Among four different test concentrations used for clove oil, 145
µLL-l was recorded as the best concentration while 140 µLL-l
and 70 mgL
-1were obtained
for Benzocaine and MS-222 respectively, based on the results obtained from statistical
analysis of SIT and RAT (p<0.05). Further, there were 0% mortalities for the 40 h test
period and 7 d after recovery for all the three anesthetics at effective concentrations
(p<0.05). In conclusion, the present study indicates that all three anesthetics perform well
in the above concentrations. However, clove oil can be used as a good substitute for
synthetic anesthetics because of its efficacy at a lower dosage with higher safety at a low
cost.
Keywords: Sedation, Ornamental carp, Ornamental fish trade, Mortality rate, Packing
density
