The Amino Acids Glutamic Acid and Alanine in Feed Increase the Alanine Content in Gonads of the Sea Urchin Mesocentrotus nudus

Abstract

Taste is an important trait of sea urchin quality. Highly contained alanine in gonads of the sea urchin Mesocentrotus nudus results in desirable taste. Past studies hypothesized that high levels of glutamic acid and/or alanine in feed increase the alanine content in the gonads. To identify the amino acids in feed that increase the alanine content in the gonads, the free amino acid content in the gonads of M. nudus of the following five treatment groups were compared at the start and end of the feeding experiment during May-July: sea urchins fed one of four experimental diets, in which glutamic acid (Glu S), alanine (Ala S), aspartic acid (Asp S), or glycine (Gly S) was supplemented, or a control diet without supplementation (Control). The alanine content in the gonads of Ala S increased significantly from the start. The content in the gonads of Glu S increased without significance. There was no significant difference in the alanine content in the gonads between Ala S and Glu S. The content in the gonads of Ala S was significantly higher than that of Asp S, Gly S, and Control. There were no significant differences in the aspartic acid and glutamic acid contents in the gonads among treatments at the end of the experiment. The higher alanine content in the gonads of Ala S than that in Glu S indicates that direct accumulation of alanine from the feed is effective. This study first identified the amino acids in feed that are closely associated with improvement in the taste of sea urchin gonad.

Microalga Coelastrella sp. Cultivation on Unhydrolyzed Molasses-Based Medium towards the Optimization of Conditions for Growth and Biomass Production under Mixotrophic Cultivation

“…These two amino acids were reported to promote protein synthesis in fish as well as to improve meat quality and immune responses in other monogastric species [64]. Supplying sea urchins with alanine or glutamic acid supplemented feed resulted in a desirable sweet taste for sea urchin gonads [65]. Glycine plays an important role in protein synthesis for mammals and fish.…”

Trace metals pollution and trophic position of three sea urchin species in the Gulf of California

“…For example, in Japan at the Tokyo Metropolitan Central Wholesale Market, where the largest amount of sea urchins is sold worldwide (Sun and Chiang 2015; Takagi et al 2020), the average price increased from US$70.5/kg to US$131.6/kg in 2018 (Takagi et al 2020). In 2020, the total worldwide production of sea urchin harvested amounts to 71,186 tones (FAO and Aquaculure Statistics, 2022).…”

Modest Dietary Protein Requirement for Sea Urchin Gonad Production Demonstrated by Feeding Trials with Consideration of Protein Leaching

“…Previous studies have demonstrated that feeding M. nudus with cultivated kelp, specifically fresh Saccharina japonica fronds or Undaria pinnatifida sporophylls, can improve the quality of barren-collected sea urchin gonads, causing the improved gonads to be more desirable than the gonads of wild M. nudus with commercial value [16,24]. However, the potential of these kelps as sea urchin food depends on their nutritional content [24][25][26][27] which changes phenologically (e.g., [28][29][30]). Additionally, depending on the season and location, it can be difficult to collect a sufficient amount of kelp for sea urchin aquaculture.…”