Dietary effect of the boiled stipe of brown alga Undaria pinnatifida on the growth and gonadal enhancement of the sea urchin Strongylocentrotus nudus

Abstract

In Miyagi Prefecture, the cultured brown alga Wakame (Undaria pinnatifida) is boiled and then salted for human consumption. The stipes are discarded. To explore a use for the discarded stipes, we studied their dietary value on the growth of the juvenile sea urchin Strongylocentrotus nudus and the gonadal enhancement of adults and compared them with that of fresh stipes, blades and sporophyll in the rearing experiment. Rapid growth in juveniles was most effectively promoted by the intake of fresh blades, with consumption of boiled stipes being next in value. The intake of boiled and salted stipe was higher than fresh stipe and sporophylls; however, sporophylls promoted the best gonadal enhancement in adults. Despite the low carbohydrate and crude protein content in boiled stipe, we estimated that boiled stipe could enhance the gonadal index by as much as 18%, the minimum level for market, after 5 months of feeding. The results suggest that boiled stipe would be an effective deterrent to the grazing intensity of the wild sea urchin within coralline flats where marine afforestation is being attempted.

Variations of chemical composition and energy content in natural and genetically defined cultivars of Macrocystis from Chile

“…Moreover, immunostimulant, immunological, and dietetic fiber properties open perspectives for use as food in fishes, sea urchins, shrimps, goats, and cattle. In these cases, seaweeds could form an important base of diet regimes (Gojón- Baez et al 1998;Agatsuma et al 2002;Casas-Valdez et al 2006;Dworjanyn et al 2007;Cruz-Suarez et al 2009;Dantagnan et al 2009). Cultured high-performance genotype constructs of Macrocystis, like those outlined in our experiments, will provide an attractive basis for these new approaches in Chile.…”

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

“…The high protein (e.g., de Jong-Westman et al, 1995;Hammer et al, 2012) and carbohydrate (Heflin et al, 2012(Heflin et al, , 2016 contents in feeds enhance gonadal production. In contract to no increase in the gonad indices at the end of the experiment in the present study, the approximate composition of each diet was similar to that of S. japonica fronds and U. pinnatifida sporophyll, which are known to enhance gonadal production (Agatsuma et al, 2002). In addition, the gonads of M. nudus in each treatment were shifted from the recovering-growing stages to the growing-premature stages, when M. nudus gonads increase in size (Agatsuma, 1997).…”

“…A total of 11 times for each diet was repeated. The percentages of Ecklonia and alginic acid sodium salt in the diets were chosen to coincide with the proximate composition of the sporophyll of U. pinnatifida and the frond of S. japonica (Agatsuma et al, 2002).…”

Quantitative Proteome Reveals Variation in the Condition Factor of Sea Urchin Strongylocentrotus nudus during the Fishing Season Using an iTRAQ-based Approach

“…The vials were immediately frozen in liquid nitrogen and stored at −80 ℃ until analysis. The Kjeldahl method was used to determine the protein content (conversion factor, %N × 6.25) according to the method of Agatsuma et al [56].…”