Deficiency and excess in dietary vitamin K3 negatively affect gilthead seabream (Sparus aurata) larvae performance and bone health

Abstract

Despite the importance of vitamin K to maintaining normal growth, survival, and bone health in fish, studies on the effect of different dietary levels of vitamin K on marine fish larvae are very scarce. In the present study, the effect of vitamin K on growth performance, incidence of bone anomalies, bone mineralization, and expression of bone biomarkers were investigated in gilthead seabream larvae by feeding microdiets with six different levels of vitamin K3 (1.32, 1.63, 4.98, 12.26, 22.90, and 58.51 mg kg−1) for 14 days. The highest total length and body weight were registered in larvae fed 4.98 mg kg−1 vitamin K3, whereas the further increase in dietary vitamin K3 up to 22.9 and 58.51 mg kg−1 reduced growth and survival. The highest incidence of anomalies in branchiostegal rays, glossohyal, or neurocranium bones was found in larvae fed the lowest vitamin K3 level (1.32 mg kg−1), whereas the increase in vitamin K3 reduced these anomalies following potential regressions with inflection points close to 5 mg kg−1 vitamin K3. However, larvae fed the highest vitamin K3 levels (22.9 and 58.51 mg kg−1) showed a high incidence of abdominal kyphosis, reduced mineralization, and unbalances in the expression of bone health-related genes. In conclusion, the present study suggested an optimum dietary level of 5 mg kg−1 of vitamin K3 to promote seabream larval growth and reduce the incidence of bone anomalies. On the contrary, the elevation of dietary vitamin K3 levels up to 22.9 and 58.51 mg kg−1 has a deleterious effect on larval performance and bone health.