Gonadal production and quality in the sea urchin Mesocentrotus nudus fed a high-protein concentrated red alga Pyropia yezoensis

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

“…The high alanine content in the gonads of Ala S compared to that in the gonads of Glu S could be due to the direct accumulation of alanine from the feed, which is effective for increasing the alanine content in gonads compared to the process of alanine synthesis from glutamic acid. Past studies reported that feeds containing 19-36% protein notably enhance gonad production (e.g., de Jong-Westman et al, 1995;Pearce et al, 2002b;Inomata et al, 2016). However, these feeds decrease the desirability of taste (e.g., Pearce et al, 2002a;Inomata et al, 2016).…”

“…Past studies reported that feeds containing 19-36% protein notably enhance gonad production (e.g., de Jong-Westman et al, 1995;Pearce et al, 2002b;Inomata et al, 2016). However, these feeds decrease the desirability of taste (e.g., Pearce et al, 2002a;Inomata et al, 2016). Robinson et al (2002) showed that gonads of sea urchins fed diets containing 250 mg/kg β-carotene (dry weight) are yellower than those fed 50 mg/kg β-carotene (dry weight).…”

“…Recently, with the decline of the natural population of the sea urchin Paracentrotus lividus, research papers focusing on sea urchin aquaculture in the Mediterranean regions have been published (e.g., Baião et al, 2019;Zupo et al, 2019). In northern Japan, studies focusing on the short-term culture of Mesocentrotus nudus adults, which are densely distributed in crustose coralline red algal communities (barrens) without erect macrophytes (reviewed by Agatsuma, 2013), have been advancing (e.g., Unuma et al, 2015;Inomata et al, 2016). Sea urchins on barrens have small gonads; exhibit undesirable gonad color, texture and taste; and are of no commercial value (e.g., Agatsuma et al, 2005;Takagi et al, 2017).…”

“…Past studies revealed that high protein and β-carotene in feed enhance gonad production (e.g., de Jong-Westman et al, 1995;Hammer et al, 2012) and improve gonad color (e.g., Robinson et al, 2002;Shpigel et al, 2005), respectively, by feeding trials with artificial diets. However, feeds with high protein content lead to undesirable color and taste (e.g., Agatsuma, 1998;Pearce et al, 2002a), low sweet-tasting amino acid (alanine and glycine) contents and high bitter-tasting amino acid (lysine and valine) contents in gonads (Hoshikawa et al, 1998;Liyana-Pathirana et al, 2002;Phillips et al, 2010;Inomata et al, 2016).…”

Identification of Sex-Specific Markers Through 2b-RAD Sequencing in the Sea Urchin (Mesocentrotus nudus)

“…Sexual dimorphism is common in aquaculture animals, and growth rate, immunocompetence, and body size generally differ significantly by sex (Mei and Gui, 2015;Jiang et al, 2017). Sea urchin is widely distributed and commercially harvested all over the world (Inomata et al, 2016), and the gonads are the only edible parts for people. In addition, edible sea urchins are important mariculture species in several Asian countries.…”