Outcomes of Trypanosoma cruzi and Trypanosoma evansi infections on health of Southern coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis) in the Brazilian Pantanal.

The occurrence of Trypanosoma spp. in wild carnivore populations has been intensively investigated during the last decades. However, the impact of these parasites on the health of free-living infected animals has been largely neglected. The Pantanal biome is the world's largest seasonal wetland, harboring a great diversity of species and habitats. This includes 174 species of mammals, of which 20 belong to the order Carnivora. The present study aimed to investigate the effect of Trypanosoma evansi and Trypanosoma cruzi infections and coinfections on the health of the most abundant carnivores in the Pantanal: coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis). We captured 39 coatis, 48 crab-eating foxes, and 19 ocelots. Diagnostic tests showed T. cruzi infection in 7 crab-eating foxes and 5 coatis. Additionally, 7 crab-eating foxes, 10 coatis, and 12 ocelots were positive for T. evansi. We observed coinfections in 9 crab-eating foxes, 8 coatis, and 2 ocelots. This is the first report of T. evansi and T. cruzi infection on the health of free-living ocelots and crab-eating foxes. We showed that single T. evansi or T. cruzi infection, as well as coinfection, caused some degree of anemia in all animals, as well as an indirect negative effect on body condition in coatis and crab-eating foxes via anemia indicators and immune investment, respectively. Furthermore, the vigorous immune investment observed in sampled coatis, crab-eating foxes and ocelots infected by T. evansi, T. cruzi and coinfected can be highly harmful to their health. Overall, our results indicate that single and combined infection with T. evansi and T. cruzi represent a severe risk to the health of wild carnivores in the Pantanal region

The growth dynamics in Brachiaria species according to nitrogen dose and shade

It was studied the effects of shading (0, 36 and 54%) and of four nitrogen doses (0, 50, 100 and 150 mg N/dm³ of soil) on the morphogenetic traits and on the tillering of grasses of Brachiaria genus (B. decumbens, B. ruziziensis and B. brizantha cv. Marandu and cv. Xaraes), cultivated in pots with 5 kg substrate. It was used a complete random design, in a 3 × 4 × 4 factorial scheme with three replications. Nitrogen promoted increase in leaf appearance rate and in average leaf blade length, whereas shading increased stem elongation rate. Leaf elongation rate and tillering varied with the interaction among shading percentages and nitrogen doses. Shading increased response efficiency of leaf elongation rate to nitrogen doses, but reduced for tillering, evidencing priority existing tillering growth in detriment to appearance of new tillers when there is light restriction for the plants. Phenotypic adjustments, in response to light reduction, indicate that the studied grasses present tolerance to moderate shading.Estudaram-se os efeitos do sombreamento (0, 36 e 54%) e de doses de nitrogênio (0, 50, 100 e 150 mg/dm³ de solo) nas características morfogênicas e no perfilhamento de gramíneas do gênero Brachiaria (B. decumbens, B. ruziziensis e B. brizantha cvs. Marandu e Xaraes) cultivadas em vasos com capacidade para 5 kg de substrato. Adotou-se o delineamento inteiramente casualizado, em esquema fatorial 3 × 4 × 4 com três repetições. O nitrogênio promoveu aumento na taxa de aparecimento de folhas e no comprimento médio das lâminas foliares, enquanto o sombreamento aumentou a taxa de alongamento do colmo. A taxa de alongamento de folhas e o perfilhamento variaram com a interação entre as percentagens de sombra e as doses de nitrogênio. O sombreamento aumentou a eficiência de resposta da taxa de alongamento de folhas às doses de nitrogênio, mas reduziu para o perfilhamento, evidenciando prioridade no crescimento de perfilhos existentes em detrimento do surgimento de novos perfilhos quando há restrição de luminosidade para as plantas. Os ajustes fenotípicos, em resposta à diminuição de luz, indicam que as forrageiras estudadas apresentam tolerância ao sombreamento moderado