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- Somatic growth and gonadal development of Paracentrotus lividus (Lamarck, 1816) fed with diets of different ingredient sourcesPublication . Lourenço, Sílvia; Cunha, Beatriz; Raposo, Andreia; Neves, Marta; Santos, Pedro M.; Gomes, Ana S.; Tecelão, Carla; Ferreira, Susana M. F.; Baptista, Teresa; Gonçalves, Sílvia C.; Pombo, AnaSea urchins’ gonads are a delicacy highly appreciated worldwide. In Europe, Paracentrotus lividus is one of the most valuable edible sea urchin species and a desired target for aquaculture. One of the challenges of echinoculture is to increase the sea urchins’ growth rate during the on-growing phase and reducing the production cycle required to obtain sea urchins of commercial size (test diameter ≈ 50 mm). The present study aimed to evaluate the growth and gonad development of P. lividus urchins fed with three dry diets for 15 weeks. The diets were formulated with ingredients of three different sources: an algae-based, a fishmeal-based and a cereals-based diet. The somatic growth was assessed by biometric indicators like the linear and specific growth rates. The gonadal development was assessed by the gonadal somatic index (GSI), gametogenesis level, proximate composition and fatty acids profile. The results obtained showed high growth rates in all the three diets tested (0.44% per day). The sea urchins fed with the cereals diet presented the highest GSI (8.22%) with higher proportion of gonads in growing and premature stages. The proximate composition of the sea urchins’ gonads was significantly affected by diet and sea urchins’ sex, particularly the lipid content. Concomitantly, fatty acids (FA) profile of the gonads was influenced by both diet and sea urchins’ sex with saturated and polyunsaturated FA playing an important role in this differentiation.
- Temporal changes in sex-specific color attributes and carotenoid concentration in the gonads (roe) of the purple sea urchin (Paracentrotus lividus) provided dry feeds supplemented with β-carotenePublication . Lourenço, Sílvia; Raposo, Andreia; Cunha, Beatriz; Pinheiro, Joaquina; Santos, Pedro M.; Gomes, Ana; Ferreira, Susana; Gil, Maria Manuel; Costa, José L.; Pombo, AnaThe market value of sea urchin roe (female and male gonads) depends on several quality criteria, such as size, color, texture, and flavor. Sea urchins given dry pellet feed often produce large gonads, but the preferred bright orange color has been difficult to achieve without the inclusion of supplementary dietary carotenoids. Gonad color depends on carotenoid concentrations (CC), and is influenced by several factors, including diet and sea urchin sex. This study aimed to evaluate the impact of sea urchin sex, gonad size, and maturation level on gonad color and CC. Small Paracentrotus lividus urchins (18 mm test diameter) were fed every 48 h with three diets of similar proximate composition (protein: 31–33% dry matter DM, fat: 9–10% DM; carbohydrates: 45–46% DM). The diets were formulated with fishmeal, algae, and plant-based ingredients and supplemented with β-carotene (100 mg Kg−1). The nutritional trial was conducted in three recirculatory aquatic systems equipped with 40 L glass tanks guaranteeing triplicates by diet with an initial biomass of 5 g L−1. The gonadosomatic index (GSI), gonad maturity and color of 15 urchins per replica were analyzed at mid-trial (103 days, T1) and at the end of the trial (173 days, T2), and compare with initial condition (baseline). At each sampling event, the color of female (F) and male (M) gonads was analyzed using qualitative (four-level visual scale) and quantitative methods (Commission Internationale de l’ Eclairage CIE L*, a* and b* color parameters). Additionally, CC was determined by spectrophotometry in pooled samples freeze-dried gonads per replica and sex and compared with baseline. At T1, 59 females and 71 males were analyzed, and results showed that females presented larger (GSI = 7.50) gonads with higher CC (117.5 μg g−1 DM) than males (GSI = 5.16 and CC = 76 μg g−1). Female gonads also presented a more intense color (a* = 8.8, b* = 17.13) than males (a* = 5.1, b* = 12.49). At T2, 61 females and 62 males were analyzed and, except for a high percentage of female gonads classified as color grade I (57%), the differences on gonad color and CC between sexes identified in T1 became non-significant. In general, the gonad color tended to become lighter (L*, baseline: 34.8 and T2: 47.2) and yellower (b*, baseline: 12.5 and T2: 17.50), and CC decreased (baseline: 201.8 μg g−1 DM and T2: 31.6 μg g−1 DM) with increasing gonad weight (baseline: 0.16 g and T2: 0.77 g) and GSI (baseline: 3.0% and T2: 9.9%). In conclusion, this study shows that the carotenoid concentration and color attributes of sea urchin gonads are influenced by sea urchin sex and gonad size. The different diets and the carotene supplementation had little or no effect on the gonad CC and color attributes, indicating that the sources and concentrations of carotenoids in the diets were not sufficient to allow the accumulation of pigments in the gonads needed to enhance the color of P. lividus urchins.
- The effects of three different feed sources on the somatic and gonadal growth of Paracentrotus lividus (Lamarck, 1816)Publication . Cunha, Beatriz Leite da; Pombo, Ana Margarida Paulino Violante; Lourenço, Sílvia Alexandra PereiraOs echinóides em geral, e os ouriços-do-mar em particular desempenham um papel predominante nas comunidades marinhas. Paracentrotus lividus (Lamarck, 1816) distribui-se por todo o Mar Mediterrâneo e pelo Atlântico Nordeste, desde a Escócia e a Irlanda até o sul de Marrocos e as Ilhas Canárias. As suas gónadas, que são denominadas comercialmente “ovas” ou “uni”, são consideradas uma iguaria de elevado valor comercial e por isso as populações de ouriços-do-mar têm sido exploradas globalmente e muitas estão sujeitas a pesca excessiva. As principais pescarias de ouriço-do-mar do mundo estão, consequentemente, em declínio, o que estimulou o interesse no desenvolvimento de métodos intensivos de cultura para espécies comercialmente importantes de ouriços-do-mar. O objetivo da investigação em produção aquícola de ouriços-do-mar é fazer a ponte entre a oferta e a procura de produtos de aquacultura, para que indivíduos adultos, com gónadas de excelente qualidade, possam estar disponíveis para o mercado durante todo o ano. O principal objetivo deste estudo foi avaliar o efeito de diferentes fontes de alimento no crescimento somático e das gónadas do ouriço-do-mar Paracentrotus lividus. Para verificar este efeito, foi realizado um ensaio nutricional de 103 dias utilizando três dietas contendo algas (Dieta A); ingredients de origem animal (Dieta B) e ingredientes de origem vegetal (Dieta C). O crescimento dos ouriços-do-mar foi avaliado através da taxa de crescimento, aumento do diâmetro, ganho em peso e indice gonadossomático. A composição bioquímica das gónadas e o desenvolvimento reprodutivo antes e no final do ensaio nutricional também foram avaliados e comparados com um controlo selvagem. Os parâmetros somáticos e o IG não apesentaram diferenças entre as três dietas, no entanto o peso gonadal foi significativamente superior nos indivíduos com a dieta C (0.76 ± 0.51 g) quando comparado com indivíduos alimentados com a dieta A (0.43 ± 0.35 g). Os indivíduos alimentados com a dieta C apresentaram melhores resultados a nível do ciclo reprodutivo, com a maior percentagem de indivíduos no estádio prematuro (III) (44.4 %). Entre os três tratamentos, a dieta B e a dieta C apresentaram uma grande percentagem de gónadas na categoria 1 (51,2% e 51,1%, respectivamente). De um modo geral, todas as dietas promoveram o crescimento e o desenvolvimento das gónadas de P. lividus e conferiram um perfil nutricional adequado