The objective of this study was to compare physiological and thermographic responses to heat stress in three breeds of cattle. Fifteen animals of each of the Nelore, Pantaneiro and Curraleiro Pe-Duro breeds, of approximately two years of age, were evaluated. Heart and respiratory rates, rectal and surface temperature of animals as well as soil temperature were recorded at 8:30 and 15:30 on six days. Variance, correlation, principal factors and canonical analyses were carried out. There were significant differences in the rectal temperature, heart and respiratory rate between breeds (p < 0.001). Nelore and Pantaneiro breeds had the highest rectal temperatures and the lowest respiratory rate (p < 0.001). Breed was also significant for surface temperatures (p < 0.05) showing that this factor significantly affected the response of the animal to heat tolerance in different ways. The Curraleiro Pe-Duro breed had the lowest surface temperatures independent of the period evaluated, with fewer animals that suffered with the climatic conditions, so this may be considered the best adapted when heat challenged under the experimental conditions. Thermography data showed a good correlation with the physiological indexes, and body area, neck and rump were the main points.

Xylitol is a sugar alcohol with five carbons that can be used in the pharmaceutical and food industries. It is industrially produced by chemical route; however, a more economical and environmentally friendly production process is of interest. In this context, this study aimed to select wild yeasts able to produce xylitol and compare their performance in sugarcane bagasse hydrolysate. For this, 960 yeast strains, isolated from soil, wood, and insects have been prospected and selected for the ability to grow on defined medium containing xylose as the sole carbon source. A total of 42 yeasts was selected and their profile of sugar consumption and metabolite production were analyzed in microscale fermentation. The six best xylose-consuming strains were molecularly identified as Meyerozyma spp. The fermentative kinetics comparisons on defined medium and on sugarcane bagasse hydrolysate showed physiological differences among these strains. Production yields vary from YP/S = 0.25 g/g to YP/S = 0.34 g/g in defined medium and from YP/S = 0.41 g/g to YP/S = 0.60 g/g in the hydrolysate. Then, the xylitol production performance of the best xylose-consuming strain obtained in the screening, which was named M. guilliermondii B12, was compared with the previously reported xylitol producing yeasts M. guilliermondii A3, Spathaspora sp. JA1, and Wickerhamomyces anomalus 740 in sugarcane bagasse hydrolysate under oxygen-limited conditions. All the yeasts were able to metabolize xylose, but W. anomalus 740 showed the highest xylitol production yield, reaching a maximum of 0.83 g xylitol/g of xylose in hydrolysate. The screening strategy allowed identification of a new M. guilliermondii strain that efficiently grows in xylose even in hydrolysate with a high content of acetic acid (~6 g/L). In addition, this study reports, for the first time, a high-efficient xylitol producing strain of W. anomalus, which achieved, to the best of our knowledge, one of the highest xylitol production yields in hydrolysate reported in the literature.

The Gram-negative intestinal microbiota of Hypostomus auroguttatus and Pimelodus maculatus, a detritivorous and an omnivorous fish species, respectively, were compared between fishes from the reservoir and the stretch of the river below the dam of the Funil hydroelectric plant, Rio de Janeiro, Brazil. Four selective culture media were used under aerobic and two under anaerobic conditions. The omnivorous species had microbiota with higher population levels compared to the detritivorous species. The number of morphotypes and population levels of total bacteria, vibrio and Bacteroides tended to be higher in summer and autumn in the reservoir, and not different in the river. The number of morphotypes of enterobacteria and total bacteria were higher in the lotic environment compared with the lentic one. The bacteria Aeromonas hydrophila and Plesiomonas shigelloides and the obligate anaerobic Fusobacterium mortiferum were the most frequently identified microorganisms in the intestine of both H. auroguttatus and P. maculatus. Both season and habitat influenced the Gram-negative intestinal microbiota of H. auroguttatus and P. maculatus. Environmental factors influenced the Gram-negative intestinal microbiota of both species with possible impact on the interrelationship between the fishes and their digestive ecosystem, although the gut microbiota composition of fishes may result from host-specific selective pressures within the gut.

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