Mechanical Properties of Bone in Channel Catfish as Affected by Vitamin C and Toxaphene

Abstract Channel catfish Ictalurus punctatus subjected to a diet deficient in vitamin C for 150 days showed a decrease in backbone collagen and hydroxyproline concentrations, whereas the mineral: Collagen ratio and bone density increased. These changes resulted in a 20% reduction in bone strength and a 46% increase in vertebral elasticity. The backbone of channel catfish exposed to the insecticide toxaphene for 90 days also had decreased collagen, but hydroxyproline concentration, mineral: Collagen ratio, and bone density all increased. These alterations in backbone composition resulted in a 34% increase in strength and a 39% decrease in vertebral elasticity. In both experiments, hydroxyproline concentrations in backbone collagen had the greatest influence on the structural properties of vertebrae, whereas collagen, calcium, and phosphorus concentrations did not. Mechanical properties seemed to be more sensitive indicators of vertebral structural integrity than did biochemical ones or bone density.