Depok, December 14, 2022. Indonesia boasts the world’s greatest wealth of fish species. According to the Ministry of Maritime Affairs and Fisheries (KKP), Indonesia has at least 4,720 species of freshwater and saltwater fish, or approximately 25% of the global fish population. Of these, 650 species are ornamental fish, including the botia (Botia macracanthus). This potential could be strategic for Indonesia in increasing foreign exchange revenue through ornamental fish exports.
Currently, the development of ornamental fish exports is hampered by a declining wild fish population. This decline is due to overfishing, juvenile exports, and habitat destruction due to illegal logging. To continue to meet market demand, fisheries production must rely not only on wild populations but also on aquaculture production using breeding technology. However, the supply of fry through this method is hampered by the asynchronous gonad maturation of male and female broodstock.
According to Prof. Dr. Drs. Abinawanto, M.Sc., a lecturer and researcher from the Faculty of Mathematics and Natural Sciences (FMIPA) at the University of Indonesia (UI), spermatozoa cryopreservation could be a solution to this problem. Cryopreservation is a technique for storing genetic material (including spermatozoa) at cold temperatures for a specific period of time. Through this method, cells can be stored for hours to years.
In his scientific speech entitled “Utilization of Natural Cryoprotectants for Fish Sperm Cryopreservation in Ex-Situ Conservation Efforts,” Prof. Abinawanto mentioned several factors that determine the success of cryopreservation. These factors include the sampling method (how to collect sperm); packaging (where the sperm is stored); diluent solutions (cryoprotectants and extenders); and storage temperature to maintain sperm viability and ability to fertilize eggs.
Sperm sampling methods for fish can be performed by stripping (massaging) the abdomen or by dissecting the fish. Stripping can yield more live spermatozoa than surgical methods. Stripping is typically used to collect sperm from goldfish, silver barb, and goldfish.
In addition to the retrieval method, the packaging used to store sperm also determines the success of cryopreservation. Cryogenic tubes (2 mL) and straws (0.2 mL) are used to store cells at cold temperatures. Cryogenic tubes are used to store sperm, while straws are used to store embryos (mammalian).
Another factor in successful cryopreservation is the use of a diluent solution to reduce the viscosity of semen during storage and prevent clumping. Diluents consist of cryoprotectants and extenders. Cryoprotectants are solutions that protect cells, both externally (extracellularly) and internally (intracellularly). Methanol, glycerol, and dimethyl sulfoxide (DMSO) are intracellular cryoprotectants, while polyvinyl pyrrolidone (PVP) and carboxymethyl cellulose (CMC) are non-natural extracellular cryoprotectants.
Prof. Abinawanto emphasized the importance of utilizing natural extracellular cryoprotectants. Besides being inexpensive, natural extracellular cryoprotectants are readily available and readily available. Examples of natural extracellular cryoprotectants include honey, skim milk, egg yolk, soy extract, date extract, and brown sugar. Natural cryoprotectants have varying effects on spermatozoa depending on the type and species used. Natural cryoprotectants can maintain motility, viability, and fertility by up to 80% and reduce abnormalities by 10–25%.
Besides cryoprotectants, extender solutions are also used as diluents in cryopreservation. Coconut water is a natural extender solution with a motility rate of 80.36% for gourami sperm cells. The extender solution contains mineral salts and sugars that function to maintain the physiological condition of the cells during storage.
“My hope for the future is to develop a cryopreservation method using natural ingredients that is easy and inexpensive so that farmers and fish farmers can utilize it. This will allow people to continue fish farming practically without the need for expensive equipment,” said Prof. Abinawanto.
Thanks to his scientific studies, Prof. Dr. Drs. Abinawanto, M.Sc., was successfully inaugurated as a Permanent Professor in Biology, Department of Biology, FMIPA UI, on Wednesday (14/12). The inauguration procession was led by the Rector of UI, Prof. Ari Kuncoro, SE, MA, Ph.D., at the UI Convention Hall, Depok Campus, and broadcast virtually through the UI Youtube channel. Also present at the inauguration event were: President Director of PT Indotech Scientific, Asep Sofyan; CEO of Pandu Holding Company, Fajar R. Budiman; National Innovation Research Agency, Prof. (Research) Heny Suseno; and Dean of FMIPA UI for the 1994–1998 period, Dr. Endang Asijati, M.Sc.
Prof. Abinawanto earned a bachelor’s degree in biology from the University of Indonesia (1986); a master’s degree in biology from the Bandung Institute of Technology (1993); and a doctoral degree from the Department of Animal Science, School of Agricultural Sciences, Nagoya University, Japan (1997). Since 1987, he has been a lecturer and researcher at the Faculty of Mathematics and Natural Sciences, University of Indonesia. His research has been conducted and published in national journals, reputable international journals, and indexed international proceedings.
Several scientific works published by Prof. Abinawanto include: The Effects of Brown Sugar as a Natural Cryoprotectant on Tor Soro (Valenciennes 1842) Spermatozoa Quality (2022); Effect of Egg Yolk of Free-Range Chicken and Methanol as a Cryoprotective Agent for the Sperm Preservation of Cyprinid Fish, Neolissochilus Soroides (Valenciennes, 1842) (2021); The Potential of Honey Supplementation in Extender for Preservation of Break Fish (Systomus Orphoides) Spermatozoa (2021); Effect of Cryopreservation on Ultrastructure and Mitochondrial Function of Albino Pangasius Catfish Spermatozoa (2020); and Effect of Honey Solution as a Natural Cryoprotectant on the Sperm Quality of Botia Fish (Chromobotia Macracanthus Bleeker 1852) (2020).
