Rice bran supplementation during nutritional recovery period of malnourished rats improves colon development.

OBJECTIVE: To investigate the colon's development in rats subjected to protein energy malnutrition followed by supplementation with rice bran. MATERIALS AND METHODS: Weaned Wistar male rats (21 days old), weight (40-50 g) were divided into two groups: diet with 17% protein (C; control group) or an aproteic diet (A; aproteic group), for 12 days. After this, 50% of the rats from each group were sacrificed. The remaining rats were further distributed in the three groups for a recovery (21 days): control (C) continued to receive the control diet whereas the aproteic group (A) received either a control diet (AC) or a control diet supplemented with 5% of rice bran (ARB). RESULTS: The A group showed alterations in the colon and cecum, excreted dry feces mass and fecal nitrogen, compared with C rats. In the proximal colon of A rats, the external muscularis and the width of the colon wall were higher whereas in the distal colon they were lower than C. After the recovery period, the relative cecum mass, colon mass and colon length of the recovered groups (AC and ARB) were higher than in the C group. Dry feces and fecal nitrogen excreted of the rats from recovered groups were lower than C group. Colon length of the AC group was lower than in the C group. Only the crypt's depth from ARB group was higher than in the C group. CONCLUSION: Control diet supplemented with 5% rice bran, reestablished the large intestine of aproteic rats. The recovery in the ARB group was even better than in the AC rats.

Pesticide fate in tropical wetlands of Brazil: an aquatic microcosm study under semi-field conditions.

A contamination of off-site aquatic environments with pesticides has been observed in the tropics, yet only sparse information exists about pesticide fate in such ecosystems. The objective of our semi-field study was to elucidate the fate of alachlor, atrazine, chlorpyrifos, endosulfan, metolachlor, profenofos, simazine, and trifluralin in the aqueous environment of the Pantanal wetland (MT, Brazil). To this aim, water and water/sediment microcosms of two sizes (0.78 and 202 l) were installed in the outskirts of this freshwater lagoon environment and pesticide dissipation was monitored for up to 50 d after application. The physical-chemical water conditions that developed in the microcosms were reproducible among field replicates for both system sizes. Pesticide dissipation was substantially enhanced for most pesticides in small microcosms relative to the large ones (reduced DT(50) by a factor of up to 5.3). The presence of sediment in microcosms led to increased persistence of chlorpyrifos, endosulfan, and trifluralin in the test systems, while for polar pesticides (alachlor, atrazine, metolachlor, profenofos, and simazine) a lesser persistence was observed. Atrazine, simazine, metolachlor, and alachlor were identified as the most persistent pesticides in large water microcosms (DT(50) > or = 47 d); in large water/sediment systems endosulfan beta, atrazine, metolachlor, and simazine showed the slowest dissipation (DT(50) > or = 44 d). A medium-term accumulation in the sediment of tropical ecosystems can be expected for chlorpyrifos and endosulfan isomers (11-35% of applied amount still extractable at 50 d after application). We conclude that the persistence of the studied pesticides in aquatic ecosystems of the tropics is not substantially lower than during summer in temperate regions.