Exercise‐induced lordosis in zebrafish Danio rerio (Hamilton, 1822)

Abstract

The anabolic effect of exercise on muscles and bones is well documented. In teleost fish, exercise has been shown to accelerate skeletogenesis, to increase bone volume, and to change the shape of vertebral bodies. Still, increased swimming has also been reported to induce malformations of the teleost vertebral column, particularly lordosis. This study examines whether zebrafish (Danio rerio) develops lordosis as a result of continuous physical exercise. Zebrafish were subjected, for 1 week, to an increased swimming exercise of 5.0, 6.5 or 8.0 total body lengths (TL) per second. Control and exercise group zebrafish were examined for the presence of vertebral abnormalities, by in vivo examination, whole mount staining for bone and cartilage and histology and micro‐computed tomography (CT) scanning. Exercise zebrafish developed a significantly higher rate of lordosis in the haemal part of the vertebral column. At the end of the experiment, the frequency of lordosis in the control groups was 0.5 ± 1.3% and that in the exercise groups was 7.5 ± 10.6%, 47.5 ± 10.6% and 92.5 ± 6.0% of 5.0, 6.5 and 8.0 TL∙s−1, respectively. Histological analysis and CT scanning revealed abnormal vertebrae with dorsal folding of the vertebral body end plates. Possible mechanisms that trigger lordotic spine malformations are discussed. This is the first study to report a quick, reliable and welfare‐compatible method of inducing skeletal abnormalities in a vertebrate model during the post‐embryonic period.

Lrp5 Mutant and Crispant Zebrafish Faithfully Model Human Osteoporosis, Establishing the Zebrafish as a Platform for CRISPR-Based Functional Screening of Osteoporosis Candidate Genes

“…(15) Zebrafish have also proved to be a relevant genetic model for the study of different skeletal diseases. (16)(17)(18)(19)(20)(21) The molecular basis and the key regulators of skeletogenesis appear to be highly conserved between zebrafish and mammals, (22)(23)(24) which is further corroborated by studies where it was shown that zebrafish and mammals respond similarly to treatment with known osteogenic compounds such as calcitriol, parathyroid hormone (PTH), and bisphosphonates. (25,26) As zebrafish are aquatic animals, the weight-bearing demand on the skeleton is reduced, enabling many skeletal mutant zebrafish lines to survive into adulthood far longer than their orthologous mouse counterparts.…”

Physiological Effects of Water Flow Induced Swimming Exercise in Seabream Sparus aurata

“…The earlier reports on exercise-enhanced growth in seabream (e.g., Ibarz et al, 2011;Blasco et al, 2015) did not mention the occurrence of exercise-induced lordosis at similar low to moderate speeds. Recent research performed in zebrafish larvae confirms that exercise induction of lordosis follows a clear dose-response curve (Printzi et al, 2020).…”

More Bone with Less Minerals? The Effects of Dietary Phosphorus on the Post-Cranial Skeleton in Zebrafish

“…Bird and Mabee [ 40 ] serve as reference for normal skeletal development in zebrafish. In addition several publications define malformations of the zebrafish axial skeleton [ 41 , 42 , 43 ]. The absence of any of the described malformation is regarded as normal in this study.…”

“…These findings strengthen the idea that P deficiency alone is not a primary cause of vertebral column abnormalities in zebrafish, and that other or additional factors trigger the development of malformations. Other factors that are currently discussed to cause vertebral column malformation in zebrafish and other teleost species are rearing temperature, excess swimming, increased rearing density or dietary vitamin A supply [ 42 , 43 , 82 , 83 ].…”