Effects of Menadione Sodium Bisulphite (Vitamin K3) Supplementation of the Diets Based on Plant Feed Ingredients on Growth and Bone Health of Gilthead Seabream (Sparus aurata) Fingerlings

The nutritional profile of aquaculture feeds can be altered with substitution of fish-based ingredients, including the vitamin contents, ultimately affecting the vitamin supply to fish. Requirements for several vitamins have been described for early life stages of species including some as salmonids and carps, but optimum levels for gilthead seabream fingerlings have not been described for most vitamins. In order to evaluate the essentiality of vitamin K in gilthead seabream fingerlings, a basal diet with low levels of marine ingredients (FM 10% and FO 6%) designed to contain five supplementation levels of vitamin K3 (0.1, 2.8, 6.3, 12.0, and 23.0 mg kg-1) was tested for 70 days. Growth and productive parameters were monitored along the trial and samples for X-ray analyses, and bone and liver molecular markers, histology, and proximal composition were taken. At the end of the experiment, growth, grp expression, and the reduced prevalence of skeletal disorders suggested that dietary vitamin K3 levels for gilthead seabream fingerlings should be above 12 mg kg-1 in diets containing a larger proportion of plant protein and vegetable oils.