Water pH effects on survival, reproductive performances, and ultrastructure of gonads, gills, and skins of the Javanese medaka (Oryzias javanicus)

Abstract

The Javanese medaka (Oryzias javanicus) has the potential to be developed as a test organism. It also exhibited many characteristics that are similar to those of well-known laboratory fishes. This study determined the effects of water pH on the survival, reproductive performances, and ultrastructure of the gonads, gills, and skins of the Javanese medaka. This study confirmed that Javanese medakas treated with pH 6-7 displayed the lowest mortality, but increased in egg production and hatchability. This supposition is supported by strong evidence from the oocytes and testes stage analyses, including histological examinations. The ultrastructure of gills and skins of fish treated in that range was also less histologically affected, indicating its suitability range. The sensitivity of the Javanese medaka towards environmental changes, in terms of the selected physiological performances and cellular level, indicate its potential as a test organism in tropical regions.

Developmental Toxicity of Zinc Oxide Nanoparticles on the Early Life Stage of Java Medaka (Oryzias javanicus Bleeker, 1856)

“…Java medaka shares many advantages with the well-known model organism Japanese medaka (O. latipes), such as their distribution, availability all year round, small size (3-4 cm), brief life span, and life cycle, rapid growth rate, readily identifiable, and easily cultured under laboratory conditions. Another notable feature of Java medaka is their sizable, see-through eggs and embryos, enabling convenient observation of their developmental stages (Amal et al, 2018(Amal et al, , 2019Salleh et al, 2017;Wittbrodt et al, 2002;Woo & Yum et, 2001).…”

Reproductive Toxicity of 3,4-dichloroaniline (3,4-DCA) on Javanese Medaka (Oryziasjavanicus, Bleeker 1854)

“…Javanese medaka ( Oryzias javanicus ) inhabit estuarine ecosystems of Peninsular Malaysia, Singapore, Indonesia, and Thailand [ 7 , 20 , 21 ]. Javanese medaka possessed significant features that make it relevant to the widely used model fish [ 21 , 22 , 23 , 24 ]. To date, several studies on the toxicity of various chemicals on Javanese medaka have been conducted [ 25 ].…”

Toxicity of Zinc Oxide Nanoparticles on the Embryo of Javanese Medaka (Oryzias javanicus Bleeker, 1854): A Comparative Study

“…The sensitivity of the species belonging to this family makes it an ideal test organism for toxicology and ecotoxicology studies. Recent studies have indeed used Javanese medaka as the test organism because of their high adaptability to both freshwater and saltwater, broad geographical range and availability throughout the year [26][27][28], short life span and life cycle, fast development [29,30], hardy, easy to identify and cultivate, short spawning period <1 min, and their transparent eggs [31]. These properties make it a suitable choice for studies, especially studies that involve early life stages.…”