Ultrastructural studies of Puntius shalynius an endemic and threatened hill stream fish

Abstract

Aim : Methodology :Results : Interpretation :Shalynai fish, Puntius shalynius is an inhabitant of freshwater, endemic and threatened hill stream fish of North-East India. The present work aimed to study the ultrastructural and functional characteristics of P. shalynius intestine, as addition to studies on nutritional requirement. This fish is considered an important species for ornamental exploitation.A total of five samples were collected from Umiam river, Meghalaya and transported to the laboratory for Transmission Electron Microscopy. Samples from intestine were cut into small pieces, fixed in Karnovsky's fixative, washed in 0.1M sodium cacodylate buffer and examined under an electron microscope.The electron microscopy of the anterior intestine from five individuals indicated that the enterocytes were elongated resting on basement membrane and covered apically with uniform microvilli. The apical cytoplasm, just below the microvilli, had no cellular organelles and formed the terminal web. Numerous mitochondria were seen along with other cell organelles such as ribosomes and nucleus. Cellular ultrastructural features were associated with digestive functions.The ultrastructural characteristics of P. shalynius intestine showed that a functional specialization exist in this fish also like other teleostean species, a common approach for active digestion in the lack of definite enzymes. The existence of microvilli seems to be important for absorptive function of the cells and enterocytes seems to function primarily in lipid absorption.

Early embryonic development of the vulnerable Shalyni barb,Pethia shalynius(Yazdani & Talukdar, 1975)

“…Studies on embryonic development have great significance as they aid towards the conservation and management of fish species by estimating the fertilization efficiencies, possible restocking of threatened fish species and production of juveniles via successful establishment of aquaculture, understanding a species' habitat requirements, and/or karyological studies to detect any chance events like polyploidy (Najafpour et al., 2019; Weber & Hostuttler, 2012). Previous studies on Pethia (=Puntius) shalynius had primarily focused on the condition factor, morphometry, reproductive cycle, ultrastructure and diet preferences (e.g., Manorama, 2016; Manorama & Ramanujam, 2014, 2017a, 2017b, 2017c). There is no information on the early embryonic development available (Froese & Pauly, 2019).…”