engleski

Early detection of bone deformities in fish

Bone deformities can occur in both wild and farmed fish. Wild fish with bone deformities tend to die early, while under farmed conditions survival rate is much higher. Despite the survival rate, fish welfare is affected and deformed fish are less attractive to buyers, which leads to major economic losses. A number of factors, including genetic, environmental and mechanical, can cause bone deformities. They can occur in different life stages, therefore, constant health monitoring is required. One of the methods for early detection of bone deformities is Dingerkus and Uhler methods (1977). This Alcian Blue-Alizarin Red double staining technique for bone and cartilage reveals the ossification process and makes early detection possible. In this work, research on early development in two different fish species, European sea bass (Dicentrarchus labrax) and common carp (Cyprinus carpio) was undertaken. European see bass fry were sampled from 15 to 90 days post hatching (dph). Sampling was performed as follows: every 5 days (15-35 dph) and then 38, 45, 50, 55, 59, 68, 71, 80, 88, and 90 dph. Common carp fry were sampled from 17 to 47 dph, 17, 22, 24, 26, 29, and 47 dph, respectively. Each group was represented with 10 specimens which were fixed in 10% buffered formalin. In addition to the collected data on skeletal system development, the early occurrence of bone deformities was noticed. Primarily, the deformities were observed on the vertebrae and fin bones. Identified deformities include: scoliosis, lordosis, kyphosis, shortening of the intervertebral space, fusion of vertebrae, bending of neural and haemal spine, thickening or splitting of fin rays. Early detection of bone deformities and possible causes could reduce economic losses in aquaculture.

bone deformities, fish, histological method

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