Increased gonad growth of the purple sea urchin (Strongylocentrotus purpuratus) fed the giant kelp (Macrocystis pyrifera) and the sea lettuce (Ulva lactuca) enriched with nutrients

Abstract

Increased gonad growth of the purple sea urchin (Strongylocentrotus purpuratus) fed the giant kelp (Macrocystis pyrifera) and the sea lettuce (Ulva lactuca) enriched with nutrients Abstract Adult (Strongylocentrotus purpuratus) purple sea urchins were fed giant kelp (Macrocystis pyrifera) and sea lettuce (Ulva lactuca) macroalgae that were unenriched and enriched with nutrients. Urchins were fed over 10 weeks (5% body weight per day) under laboratory conditions to determine the effect of macroalgae species and treatment (enriched and unenriched) on growth, gonad index and gonad quality. Significant differences were observed when urchins were fed enriched Macrocystis pyrifera (MPE). Gonad weight increased from 0.7 AE 0.1 g (mean AE SD) to 5.9 AE 1 g, and gonad index increase from 3.5 AE 1.5% to 14.9 AE 2.3% over 10 weeks. Significant differences were also noted in gonad quality, and gonad colour and firmness were better in urchins that were fed unenriched M. pyrifera (MPUE) and MPEwhereas texture did not differ between M. pyrifera treatments and unenriched U. lactuca (ULUE). With regard to taste, gonads were sweeter in MPE-fed individuals. Enriched U. lactuca (ULE) failed to grow gonads significantly; as a result, their quality was unacceptable for the market. These results suggest that S. purpuratus experience increased gonad production and quality in short periods when fed nutrient-enriched M. pyrifera.

Effects of protein and carbohydrate levels on survival, consumption and gonad index in adult sea urchinStrongylocentrotus purpuratus(Stimpson 1857) from Baja California, Mexico

“…The GI obtained in our study was not a peak value as in other studies with S. purpurtus ; Azad et al . () noted an increase in GI of 18% when S. purpuratus was fed a diet that contained 21% protein and 41% carbohydrate during 12 weeks, and Cuesta‐Gomez and Sánchez‐Saavedra () found that when M. pyrifera was enriched with nutrients (22% protein; 33% carbohydrate and 4.6% of lipid) this sea urchin showed a gonad increase of approximately 11% in 10 weeks. The factors by which these results were obtained remain unknown, necessitating more feed trials at various times during the year.…”

“…It has been exposed by George, Lawrence, Lawrence and Ford () that prepared feed can support gonadal increase throughout the year and thus solve the problem of low GI due to variability in the biochemical composition of their natural diet (i.e. algae) (Cuesta‐Gomez & Sánchez‐Saavedra ). In this study, no significant differences were found between diets, although gonad weight and GI climbed relative to initial values.…”

“…In the wild, S. purpuratus primarily consumes the giant kelp, Macrocystis pyrifera L. C Agardh, which experiences annual fluctuations in proximate content (Hernández‐Carmona, Robledo & Serviere‐Zaragoza ; Ladah ), potentially resulting in urchins with disparate gonad indices (Cuesta‐Gomez & Sánchez‐Saavedra ), affecting their commercialization. Formulated feeds are nutritionally more complete than natural foods and are essential for commercial production with regard to maximizing gonad production (Lawrence, Chang, Cao, Lawrence & Watts ).…”

“…However, basic nutritional information for the development of artificial feeds for S. purpuratus is unavailable. In B.C., few feeding studies have been conducted in purple sea urchin under controlled laboratory conditions, mainly using algae as a food source (Fonseca‐Madrigal ; Sonnenholzner, Montaño‐Moctezuma, Searcy‐Bernal & Salas‐Garza ; Cuesta‐Gomez & Sánchez‐Saavedra ).…”

Effects of Dietary Protein and Carbohydrate Levels on Gonad Index, Composition, and Color in the Purple Sea Urchin Strongylocentrotus purpuratus

“…The purple sea urchin Strongylocentrotus purpuratus from Baja California, Mexico, is an underexploited resource (Palleiro‐Nayar et al. ) that is now considered a target species for aquaculture (Cuesta‐Gomez and Sánchez‐Saavedra , ). The capture of S. purpuratus remains low because their gonads (or “uni” or “roe”) are not always adequate in size or quality, affecting its commercialization (Explorations Unlimited ; Palleiro‐Nayar et al.…”