Embryonic development of discus, Symphysodon aequifasciatus Pellegrin, 1904 in Indian condition

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The experiment was conducted to investigate the embryonic development of discus (Symphysodon aequifasiatus) and determine the time required for major egg developmental stages and hatching. Regular observations were made using optical microscope and the images were recorded using a digital camera attached to the microscope. Important water quality parameters were kept optimal for the hatching of discus eggs.

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Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 6 (2020) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2020.906.265 Embryonic Development of Discus, Symphysodon aequifasciatus Pellegrin, 1904 in Indian Condition Sambid Swain1,2, Paramita Banerjee Sawant1*, J. K. Sundaray3, E. M. Chhandaprajnadarsini4 and Milind B. Katare1 1 ICAR-Central Institute of Fisheries Education, Mumbai, India 2 Centurion University of Technology and Management, Odisha, India 3 ICAR- Central Institute of Freshwater Aquaculture, India 4 ICAR-Central Marine Fisheries Research Institute, Kochi, India *Corresponding author ABSTRACT The experiment was conducted to investigate the embryonic development of discus (Symphysodon aequifasiatus) and determine the time required for major egg Keywords developmental stages and hatching. Regular observations were made using optical microscope and the images were recorded using a digital camera attached to the Embryology, Hatching, microscope. Important water quality parameters were kept optimal for the hatching of Development, discus eggs. Newly laid eggs were oval-shaped and yellow in colour with an average Discus diameter of 1.37 ± 0.14 mm. The embryonic development of fertilized eggs was divided into 16 stages and the development of each stage was recorded in times lapse. The result Article Info revealed that cleavage occurred after 1hr after fertilization followed by development of blastula and gastrula at 20.5 hr and 24 hr after fertilization respectively. The period of Accepted: 18 May 2020 organogenesis started with the formation of embryonic notochord from 37.5 hrs after Available Online: fertilization. The appearance of a defined head and tail of the embryo with 19 somites was 10 June 2020 observed at 40.0 hrs after fertilization, whereas heart beat along with blood circulation appeared after 55.5 hrs after fertilization. The eggs hatched after 69.06 hr after fertilization. Introduction behavior which involves establishment of breeding territories by the male, selection of Discus (Symphysodon aequifasciatus), a mate for pair formation, selection of suitable cichlid are mostly found in unpopulated small site or substrate for egg laying and subsequent stream and creek of the Amazonian basin has spawning (Chellappa et al., 2005). high marketability due to its attractive colour is considered as a high-value ornamental fish One of the rare characteristics of discus (Santos et al., 2006, Wattley, 1991). It breeding is discus brooder shows parental possesses a complex and unique reproductive care and secretes nutritious mucus from its 2170
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 epidermis for feeding of hatchlings (Chong et Materials and Methods al., 2005). For easy understanding of biology of a species the knowledge of embryology can Discus brooders (103.4 ± 9.32g) were be considered indispensable tool. Inadequate procured from the local ornamental fish knowledge about the early life stage of a fish traders in Mumbai, Maharashtra, India and can affect its economic sustainability as it has were transferred to discus rearing facility of a major impact on the zoo-technical ICAR-Central institute of fisheries education, performance and the survival of the fish. Mumbai. These were acclimatized to captive condition in 1000 l glass aquaria fitted with The knowledge of embryology can not only power filter and heater along with adequate helpful in locating the spawning areas but also aeration facility for 15 days. Fishes were fed identifying the physiological requirements of with artificial commercial diet comprising of the fish which can aid to improvement in pellet feed and moist feed (Minced Chicken, culture operation and conservation of the Beef Liver) @ 6% and 8% of their body icthytofauna (Godinho et al., 2003; Anjos and weight respectively every alternate day. Pre Anjos, 2006). For determination of viability spawning behaviour was observed during this and quality of a teleost egg, observing the period, after which the pairs were transferred early developmental stage of the egg is to 100 l breeding tanks for initiating natural considered as a practical and reliable method spawning. The breeding tanks were also (Senhorine, 1993; Vallin and Nissling, 1998). equipped with power filter, thermostat and have aeration facilities for maintaining ideal The developmental period of a fish can be condition for breeding. PVC tubes of 30 cm in defined as the period in which the developing length were placed in the tank as substrates. individual entirely depends on the endo- The adhesive eggs of discus were found nutrients from the yolk of the egg (Liew et al., attached to the substrate which was latter 2006). The developmental period of the fish scrapped using scrapples and were counted. depends on the fish species and the In order to observe the developmental stage environmental conditions. The embryonic following procedure was followed i) phase of a fish which begins with the Observation was made every 30 min, 60 successful fertilization of the egg and its mins,90 min from the fertilization till the end duration includes the time interval between of the gastrula phase, start of organogenesis fertilization and eclosion (Jobling , 2002).For till emergence of heart and emergence of proper understanding the embryonic phase of heart till hatching respectively using olympus fishes is divided into two phases. SZX16 strereozoom microscope ( 15X magnification) which was photographed The first phase is the cleavage phase in which digitally by a camera attached the microscope. first cell division occurs with the appearance For each observation one third of the total of neural plates and in the second phase number of egg was selected randomly which embryo becomes noticeable as a vertebrate were latter placed in a petri-disc and were (Moyle and Cech, 2004).Since a detail observed under the microscope. The eggs embryonic study of discus fish (S. were analyzed for quality and those aequifasciatus) is scares, the current unfertilized and had fungal infection were experiment aims to provide the information discarded. The embryonic stages were about the early developmental stages which analyzed based on the recommendations of will be helpful for the fish breeders and Reid & Holdway,1995; Humphrey et al., researcher. 2003; Fugimoto et al., 2004; Fujimoto et al., 2171
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 (2006); Radael et al., (2013); Mattos et al., Embryonic development 2014. The time at which 50% of the eggs investigated attained similar stage, the The embryonic developmental stage were embryonic developmental stage were described based on the recommendations of considered. The important water quality Fujimoto et al., 2004; Humphrey et al., 2003 parameters viz. temperature, pH and dissolved and Reid & Holdway, 1995.The stages were oxygen were measured by thermometer, divided into five major period viz. cleavage, digital hand held pH probe on a daily basis., blastula, gastrula, organogenesis and eclosion ammonia (NH3-N), nitrite (NO2-N), nitrate stage. (NO3-N), Free carbon dioxide and Total hardness were also measured daily as per the Cleavage period standard protocols of APHA, 1998. The period in which the blastomere divide Results and Discussion incessantly doubling their numbers in each division until the blastodics has 64 Water quality blastomeres is termed as cleavage period (Fujimoto et al., 2004). The 1st cleavage In order to restrict any abrupt water quality started 1hr after fertilization where two round parameter the experiment was carried in a blastomeres were formed by the division of closed environmental condition. The physio- blastomere by cleavage plane, right angle to chemical parameters of water in which the the axis between second polar body and the eggs were kept were in the recommended micropyle. Eight and thirty two blastomeres levels via. Temperature, 29.2 ±0.04°C; pH, of equal size were formed due to the division 6.60 ± 0.12; 7.9mg/l ±0.25; Nitrite levels and of four and sixteen blastomers was noticed at total ammonia were never greater than 0.01 3hr and 5hrs after fertilization respectively. mg l-1 and 0.3 mg l 1 respectively over the The final cleavage division occurred at 9.5 hr entire course of the experiment. The mean after fertilization leading to formation of 64 value observed for alkalinity and hardness equal blastomeres by mitotic division of 32 were 30± 0.17 mg CaCO3 l-1 and 50 ± 0.28 blastomers. The final cleavage division mg CaCO3 l-1 respectively. resulted in formation of blastodisc with overlapping layers of blastomers. Eggs characteristics Blastula period Newly released egg were oval shaped and yellow in colour with an average diameter of A continued existence between the 1.37 ± 0.14 mm. These are adhesive in nature blastoderm and the yolk sac limits was and found attached to a solid substratum. As noticed during this stage. Blastula stage discus eggs have large amount of yolk they occurred after the seventh cleavage which are considered as polilecios. resulted in the formation of 128 bastomere and lasted till the formation of 1024 The organelles are mostly present in the blastomeres. Four to five layers of animal pole and the yolk is concentrated at blastomeres with more than 2000 cells are the vegetal pole of the egg. The unfertilized noticed within the dome shaped blastoderm at eggs are off white in colour and have a very this stage of development. Depending on the touch sensitive chorion compared to a position of each blastomers, the blastomers fertilized egg (Mattos et al., 2014) (Plate 1). gets divided but the plane of cannot be 2172
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 practically observed (Yokoya, 1966). In case Eye development of discus eggs this phase progressed from 9.5 hpf till 18.5 hpf during which the eggs Rudimentary eye vesicles resulted due to the became more or less rounded in shape evagination of cephalic region of the embryonic axis were formed on each side of Gastrula period the cephalic region in the embryo at 35.0 hpf. A well-defined and evident ocular vesicle was The most distinct characteristics of this stage noted at 39.5 hpf. is the appearance of epibole. The blastoderm expands over the surface of the yolk sac and Somites formation the embryonic region of the egg can be easily identified as in this stage the blastoderm gets Somites are rudimentary structures that are thickened. In the latter stage of Gastula, a precursor of vertebrate, ribs and axial well defined germ ring was observed. musculature of the animal. In S.aequifasciatus embryos they were initially observed at 33.30 A weak but rhythmic movement in the egg hpf. In the latter period these somites increase was noticed and the blastoderm covers the in numbers i.e 10 pairs were observed at 35 entire yolk sac region, 10 % of yolk vesicle hpf and 19 pairs at 41.5 hpf. was covered at 22hpf. About 50% of the yolk was covered by blastoderm at 28 hpf and 90% Embryonic pigmentation at 32.5 hpf. This stage is characterized with the differentiation of embryonic axis which Early signs of the pigmentation were appears as an amber colour line beside the observed as small melanophores in the yolk at yolk sac margin. Gastrula stage completes 39.5 hpf. Consequently, more number of covering the yolk by the merging of melanopores was found to be concentrated in blastoderm edges which was observed at the dorsal portion of the yolk and also in the 33.30 hpf in discus egg. ventral region of the embryo. Organogenesis period Circulatory system Organogenesis leads to formation and In discus early circulatory system consists of differentiation of major organelles. In case of a rudimentary heart which showed early discus this phase starts from the gastrula cardiac movement at 45.5 hpf but it was not phase during which the embryonic axis was possible to ascertain the blood circulation. At observed. 56.0 hpf the blood of discus embryo gets pigmented and the blood circulation was Differentiation of head and tail easily observed. The embryonic axis differentiated into Muscle contraction cephalic and caudal region with the closer of blastomere 33:30 hpf. The separation between Very slow muscle contraction was observed the two extreme were clearly marked by the at 53.0 hpf. Gradually the contraction gets prominence of anterior portion of the vigorous with the progress of time, noticeable embryonic axis. Notable appearance of optic contraction was observed at 56.5 hpf. There is primodium and seven pairs of somites were an intensification of the contraction till observed in this stage. hatching which caused disruption of chorin leading to hatching of the egg. 2173
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 Eclosion as Betta splendens (Duarte et al., 2012), Melanotaenia praecox (Radael et al., 2013) Vigorous muscle contraction was observed and Glossolepis incisus (Ferreira, 2007).The which resulted in breaking of chorion. start of organogenesis was marked with the Hatching occurred at 61.10 hpf. The early differentiation of embryonic axis after the hatchling had an underdeveloped digestive gastrula period, similar observations were system without a well-defined mouth which reported by Humphrey et al., (2003) in was recognizable at 83.0 hpf. Melanotaenia splendid. A discus egg poses similar external With the meeting of the two edges of the morphology as shown by the eggs of other blastomere, the closer of the blastomere was cichlid family viz. Astronotus ocellatus eggs. established which is observed at the end of Paes et. al. (2012). Discus eggs are adhesive epibole stage concurrent to the studies of in nature which can be related to eggs of Puvaneswari et al., (2009) and Reynalte- Cichlasoma dimerus (Meijide & Guerrero, Tataje et al., (2004) in Heteropneustes fossilis 2000).The adhesive nature of eggs is and Brycon orbignyanus respectively.The considered as an survival strategy adopted by closer of blastopore is considered as a many fish species Nakatani et al., (2001).In significant stage in the embryonic the present study, a reduction in blastomere development in which decides the success of was observed at the beginning of embryonic fertilization of the oocyte. Woynarovich & development in the cleavage stage which Horváth, 1983. Head and tail was observed coincides with the study of Puvaneswari et more evident after beginning of segmentation. al., (2009) in of Heteropneustes fossilis. The In Channa striatus,head and tail development o blastula took a longer period differentiation reported approximately 11 hpf when compared with other fish species such (Marimuthu&Haniffa,2007). Table.1 The range of the water quality parameters observed during experimental period Water quality parameters Range Temperature(0C) 28-31.5 pH As per Experimental Design Dissolved oxygen (mgl-1) 5.2-6.8 Free carbon dioxide (mgl-1) 0-4 -1 Total hardness (mgl ) 48-62 Ammonia-nitrogen (NH3-N) 0.01-0.04 Nitrite-nitrogen (NO2-N) 0-0.02 Nitrate-nitrogen (NO3-N) 0.48-2.13 2174
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 Plate.1 Embryonic Developmental Stage in Discus (A) Recently fertilized egg with only one blastomere (B) 4 cell embryonic stage (C) Blastula Stage (D) Gastrula (E) Organogenesis (F) Hatchlings Discus larvae are typical example of altricial the optic primodium was formed at 21.89 hpf larvae where hatching of discus eggs takes and 44 hpf as reported by Radael et al., place even before the complete formation of (2013) and Okada (2007) respectively. Early the embryo identical feature was recorded in hatching had un pigmented and under neotropial larvae Nakatani et al., (2001).The developed eyes, eventually after the yolk larvae were found adhered to the substrate absorption stage the eyes were pigmented and after the eclosion of the eggs by adhesive was fully developed . From this experiment it substance secreted by glands located in the can be noted that discus eggs hatches at 61.10 base of eye and head, which is considered as hpf and have similar characterstics as shown a strategy to minimize scattering of larvae by other cichlids species. into the water column .The above strategy followed are associated to parental care References observed in discus, similar observation s are noticed in other fish species like Cichlasoma Anjos, H.D.B. and Anjos,C.R., 2006. dimerus (Meiji de & Guerrero, 2000) and Reproductive biology and embryonic Astronotus ocellatus by Paes et. al., (2012). and larval development of the cardinal The ocular structure of discus developed in a tetra, Paracheirodon axelrodi Schultz, similar fashion as reported in other species 1956 (Characiformes: Characidae), in and it was attained at 46.5 hpf. In case of M. laboratory. Bol. Inst. Pesca, 32, 151- praecox and tilapia (Oreochromis niloticus), 166. 2175
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 Chellappa, S., Câmara, M. R. and Verani.J. Humphrey, C., Klumpp, D. W. and Pearson, R., 2005. Ovarian development in the R., 2003.Early development and growth amazonian red discus, Symphysodon of the east rainbowfish, Melanotaenia discus, Heckel (Osteichthyes: splendida splendid (Peters). I. Cichlidae). Brazilian Journal of Morphogenesis and ontogeny. Mar. Biology, 65, 609-616 Freshwater Res.54, 17–25. Chong, K., Ying, T.S., Foo, J., Jin, L.T and Joblin, M.,2002 . Environmental factors and Chong, A., 2005. Characterization of rates of development and growth. P.J.B. proteins in epidermal mucus of discus Hart, J.D. Reynolds (Eds.), Handbook fish (Symphysodon spp.) during of Fish Biology and Fisheries, vol. 1, parental phase. Aquaculture 249, 469- Fish Biology Blackwell Science Ltd. 476. Blackwell Publishing Company. Duarte, S.C., Vasconcellos, B.F., Vidal Jr., Liew, H. J., Ambak, M. A., and Abol-Munafi, M.V., Ferreira, A.V., Mattos., D.C. and A. B., 2006. Embryonic development of Branco, A.T., 2012. Ontogeny and clownfish Amphiprion ocellaris under embryonic description of Betta laboratory conditions. Journal of splendens, Perciformes (Regan, 1910). Sustainable Science and Management, Revista Brasileira de Saúde e Produção. 1(1), 64–73. Animal 13, 880–93. Marimuthu, K. and Haniffa, M.A., 2007. Ferreira, A.V., 2007. Ontogenia Inicial E Embryonic and larval development of Consumo De Vitelo Em Embriões De the striped snakehead Channa striatus. Melanotaenia Maçã (Glossolepis Taiwania.52, 84–92. incisus, Weber, 1907). Dissertação. Mattos,D.C, Leonardo, D. C, Paulo José Universidade Estadual do Norte Fosse, M. C., Radael, J. C., Fosse, F., Fluminense Darcy Ribeiro, Campos dos JoãoVitor, Dalcio, R.A and Manuel, V. Goytacazes., 64 pp V., 2014. Description of the ontogenic Fujimoto, T, Kataoka, T, Sakako, S., Saito, T. and larval period of discus fish Yamaha, E and Arai, K. (Symphysodona equifasciatus).Zygote. 2006.Developmental stages and germ 7, 7-11. cell lineage of de loach (Misgurnusan Meijide, F.J and Guerrero, G.A., 2000. guillicaudatus). Zoological Society of Embryonic and larval development of a Japan, v.23. p.977-989. substrate-brooding cichlid Cichlasoma Fujimoto, T, Kataoka., T, Otani, S., Saito, T., dimerus (Heckel, 1940) under Aita, T., Yamaha,E. and Arai, K., 2004. laboratory conditions. J. Zool.252, 481– Embryonic stages from cleavage to 93. gastrula in the loach Misgurnusan Moyle, P.B and Cech, J.J.J.R., 2004. Fishes: guillicaudatus. Zoolog.Sci.Jpn 21, pp. an introduction to ichthyology, 5th edn. 747–755. Pearson Prentice-Hall Inc. Upper Godinho, H.P., Santos, J.E. and Sato, Y., Saddle River, NJ, 82-96. 2003. Ontogênese larval de cinco Okada, N and Fujimura, K., 2007. espécies de peixes do São Francisco, Development of the embryo, larva and pp.133–148. In H.P. Godinho & A.L. early juvenile of Nile tilapia Oreochromis Godinho (eds.). Águas, Peixes e niloticus (Pisces: Cichlidae). Dev. Growth Pescadores do São Francisco das Diff. 49, 301–24. Minas Gerais. Belo Horizonte: PUC Paes, M.C.F., Makino, C.L., Vasquez, A.L., Minas, 468 pp. Fernandes, K.B.J. and Nakaghi, O.S.L., 2176
Int.J.Curr.Microbiol.App.Sci (2020) 9(6): 2170-2177 2012. Early development of Astronotus Bryconorbignyanus Valenciennes, 1849 ocellatus under stereomicroscopy and (Pisces, Characidae). Acta Scientiarum. scanning electron microscopy. Zygote, Biol. Sci.26, 67–71. 20, 269–76. Santos, G., Ferreira, E. and Zuanon, J., 2006. Puvaneswari, S., Marimuthu, K., Peixes comerciais de Manaus. Manaus, Karuppasamy, R. & Haniffa, A.M., Ibama. AM, Provárzea. 144 pp. 2009. Early embryonic and larval Senhorine, J.A., 1993. Procedimento para development of Indian catfish, criação de larvas de peixes. Heteropneustes fossilis. EurAsianJ. IBAMACEPTA. Pirassununga – São BioSci. 3, 84–96. Paulo. Apostila 21 pp. Radael,M.C, Leonardo, D. C, Dalcio Ricardo, Vallin, L. and Nissling, A., 1998. Cell A.D.M, Jonas, Henrique Motta, morphology as an indicator of viability JoãoVitorManhães and Manuel, V. V., of cod eggs — results from an experi- 2013. Morphophysiological mental study. Fisheries Research, 38, characterization of the embryonic 247–255. development of Melanotaenia praecox Wattley, J., 1991. Discus for the Perfectionist. (Weber & de Beaufort, 1922).Zygote, T.F.H Publications, 125 pp. 533–539. Woynarovich, E. and Horváth, L., 1983. A Reid, H.P and Holdway, D.A., 1995. Early Propagação Artificial de Peixes de development of the Australian crimson águas tropicais: Manual de Extensão. spotted rainbowfish, Melanotaenia Brasília:FAO/CODEVASF/CNP, 13 pp. fluviatilis (Pisces: Melanotaeniidae). Yokoya, S., 1966. Cell dissociation and Marine and Freshwater Research, 46 : reaggregation in early stage embryo of a 475-480. teleost, Oryzias latipes. Scient. Rep. Reynalte-Tataje, D., Zaniboni-Filho, E. and Tohoku Univ. (Ser. IV, Biol.), 32, 229- Esquivel, J.R., 2004. Embryonic and 236 larvae development of piracanjuba, How to cite this article: Sambid Swain, Paramita Banerjee Sawant, J. K. Sundaray, E. M. Chhandaprajnadarsini and Milind B. Katare. 2020. Embryonic Development of Discus, Symphysodon aequifasciatus Pellegrin, 1904 in Indian Condition. Int.J.Curr.Microbiol.App.Sci. 9(06): 2170-2177. doi: https://doi.org/10.20546/ijcmas.2020.906.265 2177