What question did this study set out to answer?

This research investigates how Bacillus probiotics in a plant-based diet affect gonad growth, survival, and coloration in purple sea urchins.

June 1, 2026Open Access

First Report on Bacillus ‐Mediated Gonad Growth and Coloration in Purple Sea Urchin ( Strongylocentrotus purpuratus ) Using a Plant‐Meal Diet

Key Points

This research investigates how Bacillus probiotics in a plant-based diet affect gonad growth, survival, and coloration in purple sea urchins.
Four dietary treatments were tested over 8 weeks: one plant-based diet without Bacillus and three probiotic-supplemented diets.
The probiotics included B. subtilis, B. velezensis, and B. amyloliquefaciens at 2 × 10^9 CFU kg −1.
Gonadosomatic index, gonad weight increase, and survival rates were measured across treatments.
Probiotic treatments achieved higher gonadosomatic index (GSI): 15.30 ± 0.76 for AFSp0, 16.10 ± 0.65 for AFSp1, and 14.30 ± 0.60 for AFSp2, while GSI was 8.23% ± 0.58% in AFC (p < 0.05).
Gonad weight increase reached 634.10% ± 32.10% in AFSp2 compared to 150.00% ± 15.90% in AFC (p < 0.001).
Survival rates were significantly higher in probiotic treatments: AFSp0 (81.81% ± 7.87%), AFSp1 (84.84% ± 1.51%), and AFSp2 (92.4% ± 1.51%) versus 45% ± 2.62% in AFC.

Abstract

Sea urchin ranching has been proposed as a potential restorative aquaculture activity to manage sea urchins from barrens affecting kelp forests globally. However, the development of sustainable and economically viable formulated feeds for sea urchin ranching is needed. This study evaluates the effect of a plant‐based diet and the incorporation of Bacillus probiotics on gonad growth, survival, and gonad coloration in purple sea urchin ( Strongylocentrotus purpuratus ). Over 8 weeks, four dietary treatments were assessed: plant‐based diet without Bacillus (AFC) and three probiotic‐supplemented diets (AFSp0, AFSp1, and AFSp2) incorporating 2 × 10 9 CFU kg −1 of B. subtilis , B. velezensis , and B. amyloliquefaciens , respectively. Probiotic treatments achieved mean (±SE) gonadosomatic index (GSI) of 15.30 ± 0.76, 16.10 ± 0.65, and 14.30 ± 0.60 for AFSp0, AFSp1, and AFSp2, respectively. In contrast, S. purpuratus in AFC obtained 8.23% ± 0.58% ( p < 0.05). Gonad weight increase (GWI) reached 634.10% ± 32.10% in AFSp2 versus 150.00% ± 15.90% in AFC ( p < 0.001). Survival rates were higher in probiotic treatments (AFSp0: 81.81% ± 7.87%; AFSp1: 84.84% ± 1.51%; and AFSp2: 92.4% ± 1.51%) compared to AFC (45% ± 2.62%). Low survival in AFC may be related to nondigestible antinutritional factors (ANFs) present in plant ingredients. Finally, spectrophotometric and high‐performance liquid chromatography (HPLC) analyses suggest the presence of putative 9‐cis‐echinenone (9CEC) at high concentrations in probiotic treatments. 9CEC concentration was 13.65 μg/g, 20.40 μg/g, and 17.10 μg/g for AFSp0, AFSp1, and AFSp2, respectively, representing increases of 31.88%, 97.10%, and 65.22% relative to the AFC control treatment (10.35 μg/g). These findings suggest that Bacillus strains improve gonad growth, survival, and gonad coloration in S. purpuratus fed a plant‐meal diet, potentially through ANFs degradation, nutrients absorption, and carotenoid metabolism enhancement. This research aims to provide practical insights for improving sea urchin ranching while assessing the broader potential of probiotic‐enhanced plant‐based nutrition in sustainable aquaculture systems.

Read Full Paperexternally

Bookmark

View Full Paper

Cite This Study

Rodríguez et al. (Thu,) studied this question.

synapsesocial.com/papers/6a1d230d02fbce9130638bbc https://doi.org/https://doi.org/10.1155/anu/7403059

Bookmark

View Full Paper