Effects of thyroid hormone treatment on the mineral density and mechanical properties of the African barb (Labeobarbus intermedius) skeleton

Here we describe the results of a preliminary study to evaluate the response of the cellular skeleton of the large African barb, Labeobarbus intermedius, to exposure to high levels of the thyroid hormone T₃ for 1 and 3 months. We examined the effects in terms of mineral density and mechanical properties of the operculum bone, as well as evaluated and compared the light microscopy features of this bone between the treatment groups and the untreated control group. We found a significant increase in bone mineral density in the treated groups compared to untreated controls, and a tendency towards a corresponding increase of bone material stiffness (Young's modulus). These findings suggest that thyroid hormone enrichment may contribute to improved skeletal properties in pond-raised fish, and help moderate osteomalacia, a commonly seen problem in aquaculture.