Inter-specific hybridization between freshwater catfish Mystus cavasius (Ham & Buch) and M. seenghala (Sykes) by artificial fertilization

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1 Indi an Journal of Experimental Biology Vol. 43, March 2005, pp Inter-specific hybridization between freshwater catfish Mystus cavasius (Ham & Buch) and M. seenghala (Sykes) by artificial fertilization A Jes u Arockia Raj, M A Haniffa*, S Seetharaman, P S Allen Benziger & Shybu Jacob Center for Aquaculture Research and Extension (CARE), St. Xavier's Coll ege (A utonomous), Palayamkottai , Indi a Received 18 June 2004; revised 29 November 2004 By employing the technique of induced ovu lation for artificial fertili zation, inter-specifi c hybrids between the threatened catfish species (Mystus cavasius x M. seenghala) were produced. Fertili zation, hatch ing and survival were signi fi can tl y different between control and hybrids. The hatching time of the hybrid was sign ificantly lower than that of the contro l. The average performance viz., hatching time and viability of larvae of the control fi sh, was sign ificantly better th an that of the hybrids. In the hybrid cross, hatchlings were mostly deformed and abnormal and after yolk absorption ultimately succumbed. Keywords: Artificial fertili zati on, Catfish, Hybridization, Mystus cavasius, M. seenghala Hybridization among fishes is a recent development of aquaculture wi th proven potenti al 1 by improving the genetic strains. In India very little attention has been paid to breeding, biology and fertility aspects of inter-generic, inter-specific and intra-specific hybrids2. Inter-specific cross-breeding in fish may lead to hybrid vigour with valuable characteristics for culture (sterility, monosex population, disease resistance and enhanced growth). Artificial hybridization between catfishes viz., Clarias gariepinus x Heterobranchus longifilis 3 C. batrachus x Heteropneustes fossilis 4 and H. fossilis x H. microps 5 has been reported. The present study on hybridization has been attempted between two Indian threatened freshwater catfishes viz., Mystus cavasius (Hamilton & Buchanan) and M. seenglzala (Sykes) commonly known as "Sonakelzuthi" and "Vellakelzuthi " in Tamil respectively. They are commercially val uable good table fishes, distributed mostly in Cauvery river basin. M. seenghala is a giant freshwater catfish, whereas M. cavasius is a smaller one. The aim of the present study is to produce hybrids and evaluate their growth performance with an ultimate objective of their commercial culture. Materials and Methods Mystus cavasius (10, 7 female and 3 male; em; g, Fig. I a) and 5 male M. seenghala (32-35 em; g; Fig. 2a) were collected from Bhavanisagar Dam (Erode Dist) during Jan uary The collected individuals were transported to CARE Aquafarm and acclimati zed in earthen ponds (1 6 x 5.3 x 1.3 m). They were fed with finely chopped chicken intesti ne ad libitum. Matured M. cavasius (female) and M. seeghala (male) were selected by their external sexual dimorphism (Figs 1 and 2 b and c) for artificial fertilization. They were inj ected with ovatide (Hemma Pharm a, Mumbai) intram usc ul arly (0.3 mllkg) and were kept separately in 500 I plastic container. After 12 hr using 0.7% sod ium chloride as extender 4 artificial fertilization was attempted on *Correspondent author Phone: Fax: haniffacare@ hotma il.com Fig. 1-(a) Mystus cavasius, (b) male, (c) femal e

2 AROCKIA RAJ et al.: INTERSPECIFIC HYBRIDIZATION BETWEEN CATFISH 287 M. cavasius only and it was treated as control (due to the un availability of M. seenghala brooders). The eggs were stripped out from the female M. cavasius. Male M. seenghala was di ssected, the testes were taken out and ground in a glass homo- Fi g. 2-(a) Mystus seenghala, (b) male, (c) fema le genizer using the extender. The milt was applied in the bowl containing eggs and the water was added 2 min after the egg and milt were mixed well. The ova and spermatozoa were incubated together for min at room temperature (30 ±1 C) in petridishes to allow fertilization. The sperm suspension was washed out using distilled water. The fertilized eggs were collected from the bowl and grouped into 5 batches of 100 each in separate petridishes. The percentage of fertili zation was calculated from the fertilized eggs. The percentage of hatching was estimated from the number of hatchlings following Lagler 6. The developmental stages were observed under Nikon microscope (U III E-400 Eclipse) and hatching was calculated6. The data were subjected to one-way Anova and Tukey's multiple range tese. Results Fertilized eggs (Fig. 3a) were counted and the per- Fig. 3-(a) Fertili zed egg, (b) 2 celled stage, (c) 12 hr old embryo, (d) just hatched larva, (e) 2 days old larva, (f) 3 days old larva

3 288 INDIAN J EXP BIOL, MARCH 2005 centage of fertilization was calculated as for the hybrids. Fertilization frequency, incubation period, hatching rate and survival data are presented in Table 1. After ferti lization, the first cleavage (Fig. 3b) was completed within 15 min in hybrids and 0.05 min in control. After 17 hr the twitching movement of the embryo was noticed both in the control and hybrid (Fig. 3c). Development of the hybrids was slightly slower than that of the control throughout embryogenesis (Fig. 3d, e and f; Table 2). M. seenghala hatchlings were taken from the induced bred progeny for morphological comparison with the control (M. cavasius hatchling) and hybrid (M. cavasius x M. seenghala; Fig. 4). Unlike the control embryos, a large number of hybrid embryos succumbed to death. In hybrids the M cavasius (Control - 3 days old) M seenghala + + M cavasius x M. seenghala (Hybrid - 3 days old) :. '. >> ~. '. ' ~, ' r..: -\'!..,,. (Induced bred offspring - 3 days old) Fig. 4-Morphological comparison of adult and 3 days old hatchlings of Mystus cavasius and M. seellghala hybrid mortality was severe during early developmental stages after hatching. The difference in survival between control and hybrid was statistically significant. Whereas 30% deformed embryos were noticed among hybrids, only 3% were observed in the control. Deformed embryos showed deviation in spinal cord, bent tail, shrinked embryos and without eyeball Table 2- Developmental stage 0ntogenic events of hybrid and control Time after fe rti lization (hr) Hybrid Control Plastodisc formation " Cleavage "d Cleavage Celled stage Celled stage Celled stage Celled stage Celled stage Morula stage Yolk Plug stage Elongation of yolk mass Appearance of embryonic rudiment Somite stage Appearance of optic rudiment (8 somite stage) 12 somite Stage Elongation of tai l Appearance of heart rud iment Appearance of gill rudiment Appearance of pectoral fin buds Twitching movement of the embryo Just hatched larva Yolk absorption Table!-Details of artificial ferti lization of hybrid and control [Values are mean± SO from 5 samples] Weight of spawner (g) Hormone ml/kg Fertilization (%) Incubation period Hatching(%) Survival (%) ---=Fe_m_a-'lcc.le oz.:..:..:...::.c:...c:.l:.:...:c..:..c...'!'m'"-a-=le (hr) Hybridization Control Ovatide 75.3" " 20.8" M. cavasius M. seellghala 0.3 ±4.2 ± 3.9 ± Ovatide 90.1b b b M. cavasius M. cavasius 0.3 ± 2.5 ±4.2 ±4.4 Similar alphabet did not significantly varied at P<O.OO I level by one way ANOVA and Tukey's mu ltiple range tese

4 AROCKIA RAJ et al.: INTERSPECIFIC HYBRIDIZATION BETWEEN CATFISH 289 Fi g. 5-Deformed embryos (a) 16 hr old ; (b), (c), (d) 18 hr old ; (e) 20 hr old; and (f) 24 hr old (Fig. 5). The average length of hatchlings was 3.0±0.2 rd mm (hybrid) and 2.5 ± 0.3 mm (control) on 3 day. Discussion The unfertilized eggs of M. cavasius (both control and hybrid) were mostly pale and transparent, but were over ripe. In the present study no successful hatchling was noticed at water temperature below 23 C or above 29 C supporting Chaudhuri and Mandal8 who suggested that water temperature was a critical factor in deciding successful development especiall y at the time of incubatio n. Survival of hybrid hatchlings was comparatively less (21%) when compared to control (51 %) and the difference was stati stically significant (? <0.001). Similarly, the difference in deformities was also statistically significant (P <0.00 1) between hybrids and control. Our success in obtaining hybrid between the two species suggests that they may be closely related In addition, comparative studies on embryological and morphological features of these two species also support this hypothesis 11. Glamuzine et al. 12 reported that th e embryonic development of the hybrid (Epinephelus costae x E. morginatus) was sli ghtly (not signifi cantly) faster throughout embryogenesis. But in the present study there was not much difference between hybrid (25 hr) and control (23 hr) with regard to incubation period. The hybrid seenghala cavasius displayed an intermediate external morphology of the two parents especiall y towards paternal species. For

5 290 INDIAN 1 EXP BIOL, MARCH 2005 instance, the dorsal fin of the hybrid was about half the size of that found in maternal M. cavasius, suggesting that the hybrid were not only true resulting from the fusion of the genetic materials of both parents3'13, but also confirming maternal heterosis. The fertilized eggs showed different hatchling in control and hybrid. Legendre et at. 3 too reported that survival was strongly influenced by their maternal parent, even though they were normally viable. In the present study the hybrid hatchlings survived only up to the absorption of yolk (3 days). Laywonyawut et al. 14 stated that post larval performance of the hybrid produced from the crosses between Clarias macrocephalus (female) x C. gariepinus (male) was better than the reciprocal hybrid which have not reached fry stage. Similarly Mukhapadhyay and Dehadrai 15 found that in crosses between C. batrachus (female) x Hetoropneustes fossilis (male) it was possible to rear the hybrids up to 8 months, whereas in reciprocal crosses the hybrids survived only up to the hatchling stage. The similarity of the embryonic development between the control and hybrids suggests that seenghala cavasius can be recommended for future aquaculture production. Acknowledgement Thanks are due to the Indian Council of Agricultural Research National Agricultural Technology Project (ICAR-NATP) for support to Dr. A.G. Ponniah, former Director and Dr. D. Kapoor, Director, National Bureau of Fish Genetic Resources (NBFGR), Lucknow who selected Centre for Aquaculture Research and Extension (CARE), St. Xavier's College for captive breeding research and to Prof. T. J. Pandian for encouragement and suggestions. References Bhowmic R M, Jana R K, Gupta S D, Kotwal, G V & Rout M, Studies on some aspects of biology and morphometry of the intergeneric hybrid Catla calla (Ham) x Labeo rohita (Ham) produced by hypophysation, Aquaculture, 23 (1981) Mahesweri U K, Somalingam 1 & Langer R K, Growth of intergeneric hybrid Cat/a cat/a (Ham) x Labeo rohita (Ham) in Tawa reservoir, Madhya Pradesh. Proc National workshop on Reservoir Fisheries (CICFRI, Barrackpore) 1990, Legendre M, Bilan des l"remiers essais d"elevage d'un silure african Hetorobranchus longifilis en mi lieis lagunarire (Lagune Ebrie. Cote d'lvoire), in Proceedings of the International Workshop on Aquaculture Research in Africa (International Development Research Center Ottawa, Canada), 1991, Padhi P, Datta B H & Mandai R K, Recipro lal hybridization between two catfishes H. fossilis and C!arias batrachus, Indian J Exp Bioi, 33 (1995) Sridhar S & Haniffa M A, Interspecific hybridization between the catfish Heteropneustes fossilis and H. microps, Curr Sci, 76 ( 1999) Lagler K F, Freshwaterfishery biology (WMC Brown Company Publishers Low a) 2"d edition 1982, I Zar 1 H, Bio Statistical analysis, 2"d edition (Printice Hall Englewood Cliffs, New Jersey) Chaudhuri A & Mandai R K, Interfamily hybridization in catfish, Indian J Exp Bioi, 17 ( 1979) Hester E, Phylogenetic relationships of sunfishes as demonstrated by hybridization, Trans American Fish Soc, 1 (1970) loo. 10 Rahman M A, Bhadra A, Begum N, Islam M S & Hussain M G, Production of hybrid vigor through cross breeding between Clarias batrachus Lin. and C. gariepinus Bur, Aquaculture, 138 (1995) Teugels G G, Ozouf F, Costa M, Legendre M Z & Parrent M, Karyological analysis of the artificial hybridization between Clarias gariepirus and Heterobranchus longifilis, J Fish Bioi, 140 (1992) Glamuzine B, Glavic N, Skarmuca B, Kozul V & Tutiman P, Early development of the hybrid Epinephelus costae X E. marginatus Aquaculture, 198 (2001) Wang Y, Cui Y, Yang Y & Cai F, Compensatory growth in hybrid tilapia Oreochromis mossambicus x 0. niloticus reared in seawater, Aquaculture, 189 (2000) 10 I. 14 Laywonyawut K, Penman D 1, McAndrew B J & Roongratri N, Preliminary study on Karyotype the hybrid catfish (Clarias gwiepinus x Clarias macrochephalus), in Genetics in aquaculture and fisheries management, edited by D Penman, N. Roongrats and B. Me Andrew (Universty of Stirling, UK) 1992, Mukhopadhyay S M & Dehadrai P V, Survival of hybrids between air-breathing catfishes Heteropneustes fossilis and Clarias batrachus, Matsya, 12&13 (1987) 162.