Water-soluble extracts from seaweeds Macrocystis pyrifera (M) and Undaria pinnatifida (U) were prepared to use the polysaccharide bioactive fraction as functional food. Chemical analysis showed that the main components of both extracts were mannitol and fucoidans. Also in both cases minor amounts of rhamnose, glucose, xylose and arabinose were determine. Content of fucose+galactose was higher in U. pinnatifida (8.7%) than in M. pyrifera (5.9%). Extracts were used as feed additive to Artemesia longinaris at inclusion levels of 1 and 2% (M1 and M2; U1 and U2), a diet without extract was used as control. Radical scavenging activities were estimated for two extracts and for midgut gland samples of experimental animals. Scavenging activity was detected in both extracts, the signal decayed to 50 and 62% in 18 min for U. pinnatifida and M. pyrifera, respectively. After 30 days of feeding, results did not show variation of survival, but growth was improved in animals fed with U1 and U2. Supplementation with 1 and 2% of U. pinnatifida showed similar quenching capacity of homogenates than those fed with M2 with a rapid 1,1-diphenylpicrylhydrazyl (DPPH) decay at 2 min of reaction. Recommended concentration for culture A. longinaris is 2%, as it is that produce the best antioxidant capacity, although the growth performance was improved also significantly only with U. pinnatifida extract.

O objetivo do presente trabalho foi determinar a digestibilidade aparente in vivo da proteína bruta de ingredientes de origem animal (farinhas de peixe, osso e carne e concentrado de proteína de lula) e ingredientes vegetais (farinha de soja) em camarões Artemesia longinaris utilizando rações contendo 0,25% de óxido de cromo. Três grupos de camarões, utilizados como replicatas, foram alimentados e as fezes coletadas. A velocidade de hidrólise da proteína de cada ração foi medida in vitro utilizando extrato enzimático da glândula do intestino médio dos camarões alimentados com a ração correspondente e foi comparado com aqueles obtidos com o extrato enzimático de camarões selvagens. Os coeficientes de digestibilidade aparente in vivo mostraram diferenças significativas entre as rações testadas (P<0,05). A farinha de peixe apresentou a maior digestibilidade (92%), enquanto valores intermediários de digestibilidade (83%) foram encontrados para a farinha de carne e ossos. A ração contendo farinha de soja e concentrado de proteína de lula resultou em menor digestibilidade (63%). Não houve diferença significativa entre os valores de digestibilidade in vitro para as rações testadas. Estes resultados indicam a limitação inerente dos ensaios enzimáticos in vitro, os quais poderiam ser complementados com estudos in vivo.

This study was undertaken to determine the in vivo crude protein apparent digestibility in the prawn Artemesia longinaris, using feeds with 0.25% of chromic oxide and animal (fish meal, meat and bone meal and squid protein concentrate) and plant (soybean meal) ingredients. Three replicate groups of prawn were fed and the feces were collected. The rate of protein hydrolysis was measured in vitro using midgut gland enzyme extract from the prawns fed the respective feeds and was compared with those found with enzyme extract of wild prawn. The in vivo apparent digestibility coefficients showed significant differences among the feeds (P<0.05). Fish meal feed presented the highest digestibility (92%); intermediate digestibility (83%) was found for meat and bone meal feed, and the less digestible feed (63%) was that containing soybean meal and squid proteins concentrate. No significant differences in the in vitro protein digestibility were found among the experimental feeds. The results indicated the limitation of in vitro enzyme assays and that it should be complemented by in vivo studies.