Anesthetic use of eugenol and benzocaine in juveniles of red tilapia (Oreochromis sp.)

Determination of Optimal Doses and Minimum Effective Concentrations of Tricaine Methanesulfonate, 2-Phenoxyethanol and Eugenol for Laboratory Managements in Nile Tilapia (Oreochromis niloticus)

“…Similarly, the optimal doses of 2-PE were 167 ppm for white sea bream and sharp snout sea bream [ 20 ], 300–350 ppm for European sea bass and 300–450 ppm for gilthead sea bream [ 19 ], 400 ppm for marbled spinefoot [ 27 ], and 600 ppm for Senegalese sole [ 26 ]. The optimal doses of EUG were 20 ppm for Nile tilapia fry [ 9 ], 50 ppm for red tilapia juvenile [ 12 ], 60 ppm for spotted sea bass [ 25 ], and 80 ppm for freshwater angelfish [ 28 ]. The reason why the current results are almost always greater than the other studies might be mainly due to the species differences, as tilapia usually requires higher anesthetic doses when compared to other fishes [ 3 , 6 , 7 ].…”

“…The influence of body weight on the anesthetic effects is even less clear. It is interesting to note that the marketable-size tilapia (from the current study) required higher doses for anesthetic induction when compared to the fry or juvenile tilapia [ 9 , 10 , 11 , 12 ]. Whether or not the small-sized fish has faster absorption and/or lower MEC than the bigger fish remain to be elucidated.…”

“…On the other hand, the effects of increasing doses on the recovery time were more variable. Some studies found more sensible direct relationships (increasing the dose prolongs the recovery time) for MS-222 in Nile tilapia [the current study], Nile tilapia fry [ 9 ], goldfish [ 32 ], zebrafish, guppy, discus [ 21 ], and spotted sea bass [ 25 ]; for 2-PE in hybrid tilapia juvenile [ 11 ], European sea bass [ 31 ], goldfish [ 32 ], and hickory shad [ 29 ]; and for EUG in Nile tilapia fry [ 9 ], red tilapia juvenile [ 12 ], and spotted sea bass [ 25 ]; while other studies, albeit less common, reported the reverse trend (increasing the dose leading to the shortening of the recovery time). This seemingly counterintuitive outcome is attributed to the fact that the duration of the anesthetic exposure is usually also be reduced at a higher dose (thus a shortened induction time) such that lower drug uptake and faster removal is expected [ 19 ].…”

“…The anesthetic agents are frequently applied in the aforementioned studies to minimize the stress and struggle, rendering them amenable to handling during invasive procedures such as blood sampling or injection. The anesthetic doses specific for tilapia have been determined by sporadic studies, for example, 120 ppm for MS-222 [ 9 ], 385–2000 ppm for 2-PE [ 10 , 11 ], and 20–100 ppm for EUG [ 9 , 12 ]. Most of these studies investigated the effects of anesthetics in the small-sized tilapia, usually below 100 g, and the anesthetic doses suitable for relatively larger size tilapia have rarely been reported.…”

Use of eugenol for anesthesia of lesser guitarfish Zapteryx brevirostris (Rhinobatidae)

“…In operations to colonize aquariums, it is not always necessary to anesthetize or sedate the fish. However, for some procedures, sedation is essential for minimizing the stress (Weinert et al, 2015) or physical damage that is caused through capture, biometry (Husen and Sharma, 2014) and transportation (Simões et al, 2011;Rucinque et al, 2016). For research or veterinary procedures, anesthesia or sedation to keep the animal unconscious or to relieve pain may be necessary (Ross and Ross, 2008).…”