Photoprotection Effects of Red Seaweed Meal (Grateloupia cf. Turuturu) as Feed Ingredient in Prawn Artemesia Longinaris.

The aim of this research was to determine the effects of adding red seaweed meal rich in ultraviolet radiation absorbing compounds (UACs) to the diet of juvenile prawn Artemesia longinaris and its possible protective effects under stress by ultraviolet radiation (UVR). Three experimental diets were prepared: control diet (D) and two diets supplemented with red seaweed Grateloupia cf. turuturu meal at two inclusion levels (D1: 1 g/100 g; D2: 2 g/100 g). Three experiments were carried out: a) 45-day feeding, b) digestibility, and c) radiation exposure experiment. After the 45-day feeding experiment, no significant differences were found in growth and survival. Accumulation of UACs was detected only in animals fed D1 and D2, and concentration was significantly higher in animals fed D2, with concentrations (12.58 ± 3.50 OD g-1 ) and (3.17 ± 0.4 OD g-1 ) after 45-day feeding and after 7-day UVR exposure, respectively. After 7 days of exposure to different light treatments, significant differences were recorded inradical scavenging activities. In all UVR treatments, rapid signal decay was recorded in the first 5 min of reaction. The red seaweed Grateloupia cf. turuturumeal constitutes an interesting source of photoprotective compounds as an additive in the diet of A. longinaris.

Effect of dietary astaxanthin on free radical scavenging capacity and nitrite stress tolerance of postlarvae shrimp, Pleoticus muelleri.

The aim of this study was to investigate the effect of astaxanthin feed supplementation and environmental nitrite stress in postlarvae of Pleoticus muelleri (15 ± 0.004 mg initial weight) under culture conditions. Diets containing three levels of astaxanthin, 0 mg kg(-1) of diet (C0), 100 mg kg(-1) of diet (C(100)), and 300 mg kg(-1) of diet (C(300)), were used. Postlarvae fed with each diet were exposed to different concentrations of nitrite (NO(2)Na) (0-200 mg L(-1)). The 96 h median lethal concentration (LC50) values of nitrite N were 76.3, 89.7, and 157 mg L(-1) for shrimps fed to C0, C(100), and C(300). The scavenging properties were evaluated against the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical by electron resonance spectroscopy (EPR). For all feed treatments, the extracts exhibited strong DPPH scavenging activity; however, shrimp fed with C(100) and C(300) showed the greatest activity to quench DPPH (62 and 59%, respectively) with respect to C0 (43%). It can be concluded that astaxanthin acts as a protector of nitrite stress in P. muelleri.

In vivo and in vitro protein digestibility of formulated feeds for Artemesia longinaris (Crustacea, Penaeidae)

This study was undertaken to determine the in vivo crude protein apparent digestibility in the prawn Artemesia longinaris, using feeds with 0.25 percent 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 percent); intermediate digestibility (83 percent) was found for meat and bone meal feed, and the less digestible feed (63 percent) 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.

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 por cento 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 por cento), enquanto valores intermediários de digestibilidade (83 por cento) 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 por cento). 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.