Determination of trace elements in Sergio mirim: an evaluation of sample preparation methods and detection techniques.

In this work, some trace elements (As, Cd, Cr, Cu, and Pb) were determined for the first time in the crustacean Sergio mirim (Decapoda: Thalassinidea: Callianassidae) from Southern Coast (Rio Grande, RS) of Brazil. The trace element determination was carried out by graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different microwave radiation-based sample digestion methods were evaluated. The analyte concentration ranged from 1.45 to 3.70 µg g-1 for As, 0.615 to 0.942 µg g-1 for Cd, 0.884 to 7.20 µg g-1 for Cr, 122 to 275 µg g-1 for Cu, and 0.390 to 0.916 µg g-1 for Pb. The limits of quantification for As, Cd, Cr, Cu, and Pb were 0.12, 0.01, 0.16, 0.92, and 0.06 µg g-1, respectively. The accuracy was evaluated by results comparison between GF AAS and ICP-MS techniques, as well as by analysis of certified reference materials of fish muscle and oyster tissue, with agreement from 92 to 108%. The feasibility of using Sergio mirim as a promising environmental bioindicator candidate was evaluated, since that it is an abundant organism in the studied area (South cost of Brazil) as well as in other places around the world.

Exogenous enzyme complex prevents intestinal soybean meal-induced enteritis in Mugil liza (Valenciennes, 1836) juvenile

ABSTRACT Four soybean meal-based diets containing increasing levels of an enzyme complex (E50, E100, E150 and E200 at 50, 100, 150 and 200 g ton-1, respectively) and one soybean meal-based diet without the enzyme complex (E0) were fed in triplicate to M. liza juveniles in a semi-static flow system with 20 fish per tank for 75 days. There were no differences between the treatments for animal performance parameters, but fish fed the enzyme complex treatment exhibited significantly (P<0.05) higher values of calcium bone retention compared with control fish. Although there was no relationship between bacterial counts in different sections of the gastrointestinal tract or enzyme levels, filamentous bacteria were increased in E50 compared with E150. All of the treatments resulted in higher bacterial counts in the stomach than in intestinal segments. Histological screening showed serious to moderate infiltration of inflammatory cells, modification in villus morphology and necrosis in some cases in fish fed the E0 diet. In addition, fish from the E0 treatment exhibited significantly (P<0.05) lower lipid deposition in the peritoneal cavity. Therefore, the use of low levels of exogenous enzyme is recommended in diets for M. liza when soybean meal is used as the main source of protein.

Exogenous enzyme complex prevents intestinal soybean meal-induced enteritis in Mugil liza (Valenciennes, 1836) juvenile.

Four soybean meal-based diets containing increasing levels of an enzyme complex (E50, E100, E150 and E200 at 50, 100, 150 and 200 g ton-1, respectively) and one soybean meal-based diet without the enzyme complex (E0) were fed in triplicate to M. liza juveniles in a semi-static flow system with 20 fish per tank for 75 days. There were no differences between the treatments for animal performance parameters, but fish fed the enzyme complex treatment exhibited significantly (P<0.05) higher values of calcium bone retention compared with control fish. Although there was no relationship between bacterial counts in different sections of the gastrointestinal tract or enzyme levels, filamentous bacteria were increased in E50 compared with E150. All of the treatments resulted in higher bacterial counts in the stomach than in intestinal segments. Histological screening showed serious to moderate infiltration of inflammatory cells, modification in villus morphology and necrosis in some cases in fish fed the E0 diet. In addition, fish from the E0 treatment exhibited significantly (P<0.05) lower lipid deposition in the peritoneal cavity. Therefore, the use of low levels of exogenous enzyme is recommended in diets for M. liza when soybean meal is used as the main source of protein.