Spatiotemporal Profile of Skeletal Development in Bonylip Barb, Osteochilus vittatus (Valenciennes, 1842)

Abstract

Skeletal development is essential in supporting aquaculture success, as failure and deformities reduce fish viability and growth. Herein, the cartilage and bone formation in the larva and juvenile of the bonylip barb, Osteochilus vittatus (Valenciennes, 1842), is described in detail for the first time. Mature fish were injected with ovaprim at 0.5 mL.kg-1 body weight, followed by artificial spawning. After fertilisation, the embryos were reared in a glass container at 28 ± 1 °C. The first hatchling was observed at 26 h and 15 min post-fertilisation (pf), and the last was observed at 48 hpf. The cartilage and bone development were observed from 1 to 30 days post-hatching (dph) by alcian blue and alizarin red S staining. Freshly hatched fish larvae had not undergone either chondrification or ossification. The cartilage was observed at 1 dph, marked with Meckel’s cartilage, ethmoid plate, and pectoral fin, as the pre-larva had a standard length (SL) of 5 mm. At 5 dph (SL of 5.6 ± 0.55 mm), 3 to 4 pairs of basidorsal and basiventral were observed. The cartilaginous development ended at 26 dph as the SL reached 14.3 ± 0.57 mm. The ossification started at 20 dph (SL of 9.24 ± 0.68 mm) and was marked with opercle and cleithrum. At 26 dph, as the post-larvae length 14.3 ± 0.57 mm, dentary, pterotic, and parasphenoid were ossified. Juvenile fish at 30 dph (SL of 21.2 ± 3.9 mm) showed completed ossification processes in the cranium and vertebrae.