Biochemical metabolism of young plants of Ucuúba (Virola surinamensis) in the presence of cadmium.

Virola surinamensis is a forest species widely distributed in the estuaries of the Amazon. These ecosystems are susceptible to contamination by Cadmium (Cd), indicating that the plant has strategies for tolerating this metal. The aim of this study was to assess the nitrogen and carbon metabolism of young plants of Ucuúba (Virola surinamensis) in the presence of cadmium with the perspective of the phytoremediation of contaminated environments. The used experimental design was a completely randomized design with five Cd concentrations (0, 15, 30, 45, and 60 mg L- 1), for 60 days. In general, Cd did not affect nitrate concentration in the root but had a positive effect on leaves. The reduction of nitrate reductase (NR) in plants exposed to Cd was followed by a decrease in ammonia, total soluble amino acids (TSA), and total soluble proteins (TSP). Cd promoted an increase in the concentration of total soluble carbohydrates (TSC), proline, sucrose, and reducing sugars in the plants. The increase in TSC, sucrose and proline, suggests a metabolic regulatory mechanism of V. surinamensis against Cd stress.

Digestibilidade aparente do farelo de palmiste em tambaqui (Colossoma macropomum) / Apparent digestibility of palm kernel meal to tambaqui (Colossoma macropomum)

O objetivo deste trabalho foi determinar a digestibilidade do farelo de palmiste (Elaeis guineensis) para o tambaqui (Colossoma macropomum), em duas classes de peso: 1 (210 alevinos de 4,45±1,18g) e 2 (54 juvenis de 115,91±4,01g). Os coeficientes de digestibilidade aparente (CDA) da matéria seca, proteína bruta e energia bruta do farelo de palmiste foram avaliados pela metodologia de substituição da dieta referência, utilizando-se 0,1% de óxido crômico como indicador externo. Os dados foram analisados pelo teste t de Student, a 5% de probabilidade. Os CDAs da matéria seca, proteína bruta e energia bruta do ingrediente foram iguais (P>0,05) nas classes de peso avaliadas. Os CDAs observados nas classes 1 e 2, respectivamente, foram: matéria seca (17,52% e 20,75%), proteína bruta (62,83% e 63,75%) e energia bruta (14,16% e 22,43%). A capacidade do tambaqui para digerir os nutrientes do farelo de palmiste não foi influenciada pelo peso corporal, e o aproveitamento satisfatório da proteína (63,29%) faz desse ingrediente uma potencial fonte alternativa de proteína em dietas para a espécie.(AU)

The objective of this work was to determine the digestibility of palm kernel meal (Elaeis guineensis) in tambaqui (Colossoma macropomum), in two weight classes: 1 (210 fingerlings of 4.45±1.18g) and 2 (54 juveniles of 115.91±4.01g). The apparent digestibility coefficients (ADC) of dry matter, crude protein and crude energy of the palm kernel meal were evaluated by the substitution of the reference diet methodology, using 0.1% chromic oxide as an external indicator. Data were analyzed by Student's t-test at 5% probability. The dry matter, crude protein and crude energy ADCs of the ingredient were the same (P> 0.05) in the weight classes evaluated. The ADCs observed in classes 1 and 2, respectively, were: dry matter (17.52% and 20.75%), crude protein (62.83% and 63.75%) and crude energy (14.16% and 22.43%). The ability of tambaqui to digest the nutrients of palm kernel meal was not influenced by body weight, and satisfactory protein utilization (63.29%) makes this ingredient a potential alternative source of protein in diets for the species.(AU)