The sea urchin Tripneustes depressus is a potential fishing resource on the coast of Baja California Sur due to the quality of its gonads for human consumption. An alternative to increase gonadal quality in culture is to control the nutritional balance of the feed. The effect of different formulated diets on the quality of T. depressus gonads was evaluated.
Three balanced feeds were formulated and elaborated, two based on previously selected algae (Eisenia arborea, Sargassum sinicola), and a mixed one combining both. Sixty organisms (8-11 cm in diameter) previously acclimatized without feeding (three replicates of 20 organisms for each treatment) and three controls with each type of natural algae were placed in the laboratory. The organisms were fed ad libitum for three months. At the end of the experiment, the quality of the gonads was evaluated for each treatment, considering characteristics such as gonadal weight, color, texture, firmness, and flavor. Additionally, to know the initial conditions, 20 wild organisms recently collected and 20 after the acclimatization period were sacrificed, as well as at the end of the experiment another 20 wild organisms were sacrificed.
The highest gonadal weights were observed in the wild organisms before and after the experiment, as well as in the treatment with E. arborea, with significant differences being found between these and the rest of the treatments (H=165.46; p<0.0001). When analyzing the quality characteristics by treatment, we can observe the highest percentages of "excellent" and "very good" gonads in the organisms prior to and at the end of the experiment, as well as in the treatment with E. arborea, finding significant differences between these and the rest of the treatments (Color: H=105.93, p<0.0001; Texture: H=128.06, p<0.0001; Firmness: H=135.90, p<0.0001; Taste: H=78.37, p<0.0001). In particular, the color parameters showed high values ??of L and low values ??of a in all treatments, and higher values ??of b in the organisms before and after the experiment, as well as in the treatment with E. arborea. The ΔLab values ??were lower in the organisms before and after the experiment, as well as in the treatment with E. arborea, which corresponds to gonads with better coloration, presenting significant differences between these and the rest of the treatments (L: H=34.85, p<0.0001, a: H=59.13, p<0.0001, b: H=123.10, p<0.0001, ΔLab: H=99.65, p <0.0001).
Apparently, the use of algae, specifically E. arborea, was favorable in the formulation of balanced food in T. depressus, obtaining good quality gonads when using this species of algae naturally. The commercial quality of the gonads of this species could represent a viable alternative for the development of sea urchin aquaculture in Mexico.