Fish Anaesthetic Properties of Some Local Plant Material - Faculty of ...

Tropical Agricultural Research & Extension 9, 2006Fish Anaesthetic Properties of Some Local Plant MaterialJ.C. Ramanayaka and *N.S.B.M. AtapattuDepartment of Animal Science, Faculty of Agriculture, University of Ruhuna,Mapalana, Kamburupitiya, Sri Lanka.Accepted 02 nd August, 2006ABSTRACTObjective of this study was to evaluate the anesthetic properties of several plant extractsin common carp (Cyprinus carpio). Extractions were made by grinding 50 g ofplant material with 500 ml of water followed by crushing and filtering. Induction timesof anesthesia to four pre-determined stages (S 1 -S 4 ) were recorded for different concentrationsof plants extracts. When fish lost the total equilibrium (S 4 ), it was placed in afresh water tank and the recovery time was recorded. Each concentration of the plantextract was tested in ten replicate fish. Clove (Eugnia carioplyllum), Clotalaria(Clotalaria sp), Kalawel (Derris scandens) and Kukuru extracts showed high to mediumlevel of anesthetic properties. Clove gave the best induction and recovery times.At 3 ml plant extract/L, fish attained S 4 within 5.5 minutes and recovered within 15minutes. Even though clotalaria at 2.5ml/L induced S 4 within 4.3 minutes, the recoverytime was 64 minutes. Kalawel had a narrow effective range and acted fast. At 2 ml/Lfish attained S 4 within 8.7 minutes and recovered in 43 minutes. At 3.75 ml/L Kukuruhad 20 minutes induction and 60 minutes recovery time. Welan and Medella(Barrigtonia racemosa) showed some anesthetic properties but were less effective dueto longer induction and recovery times. Thiththawel (Anamirla coculus), Thala(Corypha ambraculifera) and Daluk (Euphorabhia antiqurum) showed no anestheticproperties but were toxic. It is concluded that anaesthetic properties of clove are comparablewith the recommended criteria for being an effective anesthetic.Key words: fish, anaesthesiaIn fish farming, various management practicessuch as weighing, tagging, strippingand transportation are required to handlefish. Handling of fish out of water is verystressful and even lethal to fish dependingon the severity of the stress. In order tominimize the stress of transportation fishshould be immobilized. Fish are among themost widely used laboratory animals.Therefore, apart from aquaculture relatedhandling, on many occasions fish are subjectedto stressful surgical and experimentalprocedures. Fish are considered as sentientanimals and thus are included in ethicalcodes. Therefore, from legal and ethicalpoint of view, fish should be anaestheized when they are subjected to any stressfulhandlings.*Corresponding Author

J.C. Ramanayaka & N.S.B.M. Atapattu : Fish Anaesthetic Properties of Local Plant MaterialsChemical anesthetics are now widelyused for fish anesthesia. The chemical anestheticsused in fish have changed gradually(Stuart 1985). Many of the first generationanesthetics such as ether, chloroform,menthol, urethane and cocaine arenow not in use due to, health hazards, lackof adequate efficacy and adverse physiologicaleffects on fish. The second generationof fish anesthetics are the chemicalssuch as tricaine, benzocaine and quinaldine.Though these anesthetics are effective,only tricaine has been permitted touse in food fish anesthesia mainly due toenvironmental and health risks (Markingand Mayer, 1985). This has resulted in arenewed interest to develop ‘green anaesthetic’with low environmental and healthrisks.Though the term anesthesia is technical,for thousands of years people used plantextract to kill or immobilize fish. Theseplant extracts are added to water in variousforms and ways. The efficacy variesgreatly from light sedation to killing. Theobjective of the present study is to evaluatethe fish anaethetic properties of someplant materials commonly used by SriLankan fishermen to immobilize or to killfish.Extracts of ten plant materials were usedfor the experiment (Table 1).The method of extraction was similar forall pant materials except for Thiththa Wel.50 g of fresh pant material were blended ina kitchen blender (300 rpm) with 500 ml ofdistilled water.Then the extract was collected into a flaskby crushing and filtering through a pieceTable 1. Plant materials studied for fishanesthetic propertiesCommonnameBotanicalnameplant part usedto get extractClove Eugnia ariophylumdry flower budsClotalaria Clotalaria spp leavesKalawel Derris scandens stemKukuruWelanMedellaAnduBarringtoniaraecemosaEryagaum foetidanyThithawel Anamirla cocculusThala Corypha ambraculiferaDaluk Euphorabiaantiquarumnut (fruits)nut (fruits)barkwhole plantNutnut (fruit)stemof cotton cloth. The method of extractionfor Thiththa Wel was as follow; 50 g offresh nut of Thiththa Wel was mixed with5 ml of coconut oil and then crushed togetherusing a motar and pestle. 55 g ofthis mixture was then mixed with 500 mlof water and belnded. The extraction wascollected by crushing and filtering thougha cotton cloth.2-3 months old common carp (Cyprinuscarpio) of indeterminate sex was used forthe experiment. Fish were kept in an outdoorcement tank before being used for theexperiment. A pre-trial was conducted toestablish the effective dose range of eachplant extract.A glass tank (45 L * 25 W*29.5 H cm)was filled upto 18 cm with fresh tap waterso that the tank contains 20 l of water. A

Tropical Agricultural Research & Extension 9, 2006measured volume of plant extract wasadded to the water and mixed thoroughlyfor 20 seconds. Then a fish was introducedinto the tank. The time taken toreach pre determined stages of anaesthesiawas taken (Table 2).Table 2. Stages of anesthesia and theircharacters (Modified from Stuart 1985).Stage ofanesthesiaCharacters used to identify1 Loss of equilibrium, but fish respondedto tactile stimuli2 reduced response, partial loss of equilibrium,fish can hold on hand, reducedoperculum activity3 loss of response, can pull by posteriorfin4 total loss of equilibrium, fish lay downAs soon as the fish reached to S 4 anesthesia,it was transferred to a glass tankfilled with 40 l of fresh tap water. Thetank was aerated with normal circuit ofaerator. The time taken to gain the completeequilibrium was taken as the recoverytime. Each concentration of all theplant extracts was replicated in 10 fish. Nofish was reused. The weight of the fishvaried from 100-150 g.Time taken to reach different stages of anesthesiaand recovery time from S 4 aregiven in Table 3.The effectiveness of the plant extractswas decided on the time taken to reach toS 4 anesthesia and the recovery time. Markingand Mayer (1985) recommended desirableinduction and recovery times of anesthesiaof fish as 3 and 5 minutes, respectively.None of the tested plant extract metthe recommended induction and recoverytime regimes. This less effectiveness withrespect to induction and recovery timesmay partly be due to the low concentrationof active ingredients in the crude plant extractswe used. Much of the fish anestheticstudies have been conducted in salmonidswhose oxygen demand is high (Sedgwick(1985). The transfer of anesthetics to andfrom the fish takes place via the gills andthus the effectiveness of anaesthetics inthese active fishes are higher compared tocarps. The observed less effectiveness maybe attributed to this fact as well.Despite the fact that plant extracts are notas effective as an ideal anesthetic shouldbe, a considerable level of anesthetic propertiescould be found even in crude plantextracts. Clove, Clotalaria, Kalawel andKukuru extracts showed high to mediumlevels of anesthetic properties. Clotalariaat 3-3.75 ml/l level gave around 3 minutesinduction time. However, recovery timewas far exceeded the recommended time.Clove at 3 ml/l gave the closest charactersto the ideal anesthetic. Munday and Wilson(1997) and Peake (1998) have alsoreported the anesthetic properties of cloveoil. We observed 5.5 minutes inductiontime and 15 minutes recovery times at 3ml/l concentration. Peake (1998) reported6 minutes of induction and 7 minutes ofrecovery time for clove oil. Values weobserved were more or less similar to thevalues reported by Gilderbus and Marking(1987) for CO 2 at 240-265 mg/l; i.e 3.1minutes induction and 16 minutes recoverytime. Marking and Mayer (1985) showedthat CO 2 was stressful and lethal after repeatedexposure because CO 2 acidifies waterand reduces desolved O 2 . Other adverse

J.C. Ramanayaka & N.S.B.M. Atapattu : Fish Anaesthetic Properties of Local Plant MaterialsTable 3. Time taken to reach different stages of anesthesia and to recover as affectedby the plant extract and the concentration.Time taken to reach different stages of anesthesia and recovery (Min)Plant extract Concentration (ml/l) S1 S2 S3 S4 RecoveryClove 1 1.5 4.30 7 12 22 72 4.5 5.3 7 11 92.5 3 4 5 6 143 3 4 5 5.5 15.Clotalaria 1 1.25 1.1 3.6 8.4 17.7 602.5 0.6 1.3 2.1 4.20 643.75 1.3 1.4 2.3 3.3 84.35 1.2 1.6 2.1 3.2 116.1Kalawel 1 2 2.7 4.1 5.6 8.7 432.25 2.4 3.6 5.5 8.1 57.12.5 2 3.9 6.2 8.6 80.52.75 2 3.4 4.4 6.2 161.2Kukuru 1 1.25 21 31 33 50 102.5 7 10 21 33 173.75 7 9 17 20 605 7 10 18 20 90Welan 1 5 27.8 44.9 75.3 102. 24.27.5 11.6 19 25.1 35.7 40.915 5.9 9.2 13.7 20.1 53.7Medella 5 20 31.7 42.5 53.7 106.715 9.8 14 17.3 23.4 135.3Andu 2 2.5 41 755 25 46.6Thithawel 3 5 35 46.6 56.6 66.610 18.6 25 33 45.3Thala 3 2.5 22.6 33.3 42 50.6Daluk 3 5 13.6 22.6 38.6 431 Means of ten fish. No fish died2 Studied only up to S 23Fish died

Tropical Agricultural Research & Extension 9, 2006effects of CO 2 include erythrocute swelling,increased lactic acid levels and reducedoxygen partial pressure in blood. Sincemany countries have now banned chemicalanesthetics in aquacultural practices clovecan be recommended as an effective anaestheticagent for food fish.Some doses of Clotalaria and Kalawelshowed fairly effective induction times.However, both of these plant extracts hadmuch longer recovery times. Kalawelcould be identified as the most effective ininducing anaesthesia. Also it had narrowdose range of effectiveness. Even at 2 ml/lconcentration it caused S 4 anaesthesiawithin 8.7 minutes but took 43 minutes torecover. The effectiveness of Kalawel iscomparable with chemical anesthetic ChoralHydrate at 0.9g/l (Stuart 1985). Kukurualso showed some anesthetic properties.3-3.75-5 ml/l concentration caused S 4in 20 minutes. Interestingly concentrationsof 1.25 and 2.5 ml/l of kukuru and 5 ml/lof welan had shorter recovery times thantheir respective induction times. No chemicalanaesthetic has shown to have thisproperty. The reason for this peculiarity isnot clear.Welan and Medella can also be categorizedas slow acting plant extracts. Toachieve S 4 in 20 minutes both welan andmedella required as high dose as 15 ml/l.The recovery times were also high forthese plant extracts. The longer recoverytimes of these extracts may be helpfulwhen fish are transported for a long distanceunder anesthesia. Stuart (1985)compiled the chemical anesthetics suitablefor fish transportation under anesthesia.Anesthetic properties of Welan andMedella fairly comparable with the chemicalsmetomidate and etomidate at 0.75 and1 mg/l. Andu was the least effective. Sinceit took 46 minutes to reach S 2 at 5ml/l, weassumed that anesthetic properties of anduwas not study worthy. Thiththawel, Thalaand Daluk showed no anesthetic properties.They were found to have toxic effectsthan anesthetic properties (as claimed byindigenous knowledge) since all the fishexposed to above plant extracts did notrecover but died.Fish were observed for five days afterthe completion of the study. No fishanaesthetized with Clove, Cloralaria,Kalawel, Kukuru, Welan, Midella andAndu died during that period and fishshowed normal activity indicating thatthose plant extracts have no adverse effects.However, how these plant extractsaffect the physiological processes are notclear. Therefore, further experiments needto be conducted to establish such effect, ifany, if fish are to be anaesthetized usingthese extracts, for physiologica experiments.Anaesthetic properties of Clotalaria,Kalawel and Kukuru were found tobe sufficient enough for many aquaculturalpractices. Welan and medella couldbe useful for fish transportation. Andu,thala, thithawel and daluk should not beused as an anaesthetics. Further researchesare needed to identify the active ingredientsand possible effects on physiology ofthe fish.REFERENCESGilderhus, P.A. and Marking, L.L (1987).Comparative efficacy of 16 anaestheticchemicals in rainbow trout.North American Journal of FisheriesManagement.

J.C. Ramanayaka & N.S.B.M. Atapattu : Fish Anaesthetic Properties of Local Plant MaterialsMarking, L.L. and Mayer, F. (1985). Arebetter anaesthetics needed in fisheries.Fisheries. 10(6):2-5Munday, P.L. and Wilson, S.K. (1997).Comparative efficacy of clove oiland other chemicals in anaesthetic ofcoral reef fish. Journal of Fish Biology.51(5):931-938.Peake, S. (1998). Sodium bicarbonate andclove oil as potential anaesthetic fornon salmonid fishes. North AmericanJournal of Fisheries Management.18:919-924.Sedgwick, C.J. (1988). Anaesthesia forfish. Veterinary Clinic in NorthAmerica: Food and Animal Practice.21(3): 737-742.Stuart, N.C. (1985). Anaesthesia in fish.Journal of Small Animal Practices.22:377-384.