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

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 K-3 (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 K-3, whereas the further increase in dietary vitamin K-3 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 K-3 level (1.32 mg kg(-1)), whereas the increase in vitamin K-3 reduced these anomalies following potential regressions with inflection points close to 5 mg kg(-1) vitamin K-3. However, larvae fed the highest vitamin K-3 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 K-3 to promote seabream larval growth and reduce the incidence of bone anomalies. On the contrary, the elevation of dietary vitamin K-3 levels up to 22.9 and 58.51 mg kg(-1) has a deleterious effect on larval performance and bone health.

Automated summary

Despite limited research, this study found that vitamin K is important for growth and bone health in gilthead seabream larvae. Feeding larvae with 4.98 mg kg(-1) of vitamin K-3 resulted in the highest growth, while higher levels of vitamin K-3 reduced growth and survival. The incidence of bone anomalies decreased as the level of vitamin K-3 increased, with the optimal level being 5 mg kg(-1). However, high levels of vitamin K-3 (22.9 and 58.51 mg kg(-1)) caused deformities, reduced mineralization, and imbalances in bone health-related gene expression.