A quantitative determination of deformities in barramundi (Lates calcarifer; Bloch) fed a vitamin deficient diet

Abstract

Cultured barramundi, Lates calcarifer, suffer from abnormalities affecting the jaw, opercula and spine. The aim of this study was to quantify for the first time the effects of supplemented dietary vitamin C, vitamin D3 and ultraviolet (UV) light on the development of jaw, opercula and spinal deformities. Four diets were formulated to contain (i) no vitamin C or vitamin D3, (ii) only vitamin D3, (iii) only vitamin C and (iv) both vitamin C and vitamin D3. In addition, two commercial diets (diets 5 and 6) were also tested. These diets were replicated in the presence, and in the absence, of ultraviolet (UV) light as this may also affect skeletal development. Diets formulated with 170 ± 1 mg kg−1 and 195 ± 0.5 mg kg−1 of vitamin C (diets 3 and 4, respectively) and the commercial diets (diets 5 and 6) had significantly lower incidences of spinal deformities (0–2.5%; P < 0.01) and opercula deformities (nil detected). Spinal deformities were 'broken back' syndrome, which was found only in the precaudal vertebrae, and lordosis which was only in the caudal vertebrae. UV light and vitamin D3 did not affect spinal or opercula deformities. There was no change in the occurrence of jaw deformities in vitamin C, vitamin D3 or UV light treatments.