Dietary shifts in the juvenile sea urchin Strongylocentrotus intermedius associated with the development of digestive enzymes

Abstract

ingested diets were observed for urchins >3 mm in TD. Our results suggest that the primary nutrient source of S. intermedius shifts from microalgae to macroalgae at ≈6 mm TD, and that macroalgae digestion efficiency in urchins ≥3 mm TD gradually improves because of activation of the enzymes. Highly activated enzymes enable sea urchins to efficiently digest nutrients stored in the bodies of macroalgae, allowing the primary nutrient source of S. intermedius to shift from microalgae to macroalgae.

Digestive Enzyme Activities and Gut Emptying Are Correlated with the Reciprocal Regulation of TRPA1 Ion Channel and Serotonin in the Gut of the Sea Urchin Strongylocentrotus intermedius

“…From the results in this experiment, we found that an interregulatory relationship existed between TRPA1 and 5-HT in the gut of S. intermedius. Amylase and pepsin as representative digestive enzymes of sea urchins and their activities have been extensively used to evaluate the food digestion and absorption of sea urchins [15,16]. To investigate whether a correlation exists between digestive enzyme (amylase and pepsin) activities and the reciprocal regulation of TRPA1 and 5-HT in the gut of S. intermedius, we conducted a set of cascading experiments.…”

“…The absorption and utilization of nutrients by S. intermedius are directly affected by digestive enzymes activities [15,16]. In this experiment, we used pepsin and amylase enzymes activities as two representative indicators to evaluate digestive and absorptive capacities of sea urchins.…”

“…Low food digestibility of sea urchins is correlated with the activity of digestive enzymes [7] and the duration during which the food stays in their gut [14]. Digestive enzymes directly affect the absorption and utilization of nutrients in the sea urchin Strongylocentrotus intermedius, thereby affecting their growth [15,16]. Amylase and pepsin have been extensively studied as representative digestive enzymes of sea urchins and their activities have been used to assess the digestive and absorptive capacities of sea urchins [15,16].…”

“…Digestive enzymes directly affect the absorption and utilization of nutrients in the sea urchin Strongylocentrotus intermedius, thereby affecting their growth [15,16]. Amylase and pepsin have been extensively studied as representative digestive enzymes of sea urchins and their activities have been used to assess the digestive and absorptive capacities of sea urchins [15,16]. Gastric emptying is a common method used to quantify gastric motility [17], which greatly affects the rate of digestion and absorption of nutrients [18][19][20][21].…”

Nutrient enrichment and probiotics for sea urchin Anthocidaris crassipina larvae in captivity to promote large‐scale aquaculture

“…However, sea urchins have a complex life history from larval to adult. They feed on floating microalgae during the planktonic larval phase, and postsettlement juveniles feed on sessile microalgae (Onitsuka et al, 2015). Therefore, different stages may have different digestive enzymes, and these digestive enzymes will affect the digestion and absorption of food by sea urchins and then affect growth or death.…”