Exigências de energia de borregas mestiças alimentadas com níveis crescentes de concentrado na dieta / Energy requirements of crossbreed ewe lambs fed with increasing dietary levels of concentrate

Objetivou-se estimar as exigências energéticas de borregas mestiças confinadas, alimentadas com níveis crescentes de concentrado na dieta. Foram avaliadas 36 borregas, com peso corporal inicial de 23,7±3,67kg. Seis animais foram abatidos no início do experimento para obtenção dos valores do grupo referência. Os demais (30 animais) foram distribuídos em cinco tratamentos: mantença (alimentação restrita com feno de capim Tifton) e suplementados com níveis crescentes de concentrado (20, 40, 60 e 80%) em base de matéria seca (seis animais por tratamento). As borregas foram abatidas quando atingiram 37,70±9,89kg. Os níveis de concentrado influenciaram a eficiência de utilização da energia metabolizável para mantença (km) e consequentemente as exigências diárias de energia metabolizável para mantença. A exigência de energia líquida para mantença de borregas mestiças em crescimento é 57 kcal/PCJ0,75/dia, em que PCJ é o peso corporal em jejum. As borregas com 20kg apresentaram exigência de energia líquida para 100g de ganho de peso diário de 465kcal/dia. As borregas com 40kg de peso corporal exigiram 930kcal/dia de energia líquida para o mesmo ganho. A exigência líquida para mantença de borregas pode ser estimada pela equação: ELm (Mcal/dia) = 0,057* PCJ0,75. A exigência líquida de energia para ganho de borregas mestiças (Mcal/dia) pode ser estimada a partir da equação: ELg = 0,524 x PVJ0,75 x GPCVZ1,21, em que GPCVZ é o ganho de peso do corpo vazio. As dietas influenciam as eficiências de usos da energia metabolizável para mantença (km) e ganho (kg).(AU)

The aim of this study was to estimate the energy requirements of crossbreed ewe lambs in a feedlot fed with increasing levels of concentrate in the diet. 36 ewe lambs were evaluated with initial body weight of 23.7±3.67kg. Six animals were slaughtered at the beginning of the experiment to obtain the reference group values. Animals (30) were distributed in five treatments: maintenance (feed restricted with Tifton grass hay) and those supplemented with increasing dietary levels of concentrate (20, 40, 60 and 80%) on a dry matter basis (six animals per treatment). The ewe lambs were slaughtered when they reached 37.70±9.89kg. The concentrate levels influenced the utilization efficiency of metabolizable energy for maintenance (km) and consequently the daily requirements of metabolizable energy for maintenance. The net energy requirements for maintenance of crossbred lambs in growth is 57kcal/FCW 0.75/day, where FCW is body weight on fasting. The ewe lambs with 20kg presented net energy requirement for 100g daily weight gain of 465kcal/day. The ewe lambs with 40kg of body weight required 930 kcal/day of net energy for the same gain. The net energy requirement for maintenance of ewe lambs can be estimated by the equation: NEm (Mcal/day) = 0.057 * FCW0.75. The net energy requirement for crossbred ewe lambs gain (Mcal/day) can be estimated from the equation: NEg (Mcal/day) = 0.524*FCW 0.75*GEBW1.21, where GEBW represented gain empty body weight. Diets affect the efficiencies of uses of metabolizable energy for maintenance (km) and gain (kg).(AU)

Phenotypic characteristics for discrimination between advanced genotypes of Brachiaria ruziziensis.

The aim of this study was to use multivariate methods and Pearson and partial correlations to disregard phenotypic characteristics that contribute little to differentiation between Brachiaria ruziziensis genotypes. Eighty-one genotypes of B. ruziziensis were assessed in completely randomized blocks with three replications. Ten phenotypic characteristics were assessed: plant height, leaf length, leaf width, sheath length, length of the flower stem, length of the inflorescence axis, number of racemes per inflorescence, length of the basal raceme, number of spikelets per basal raceme, and width of the rachis. The best traits for differentiation between genotypes were determined by assessing relative contribution to diversity, canonical variables, as well as Pearson and partial correlations. Four canonical variables were found to account for 57% of the overall variation, while plant height, sheath length, and number of racemes per inflorescence were considered traits that could potentially be disregarded in future assessments.

Quantitative and qualitative carcass characteristics of feedlot ewes subjected to increasing levels of concentrate in the diet / Características quantitativas e qualitativas da carcaça de borregas confinadas submetidas a níveis crescentes de concentrado na dieta

The aim of this study was to evaluate the effect of increasing levels of concentrate on the quantitative and qualitative carcass characteristics of feedlot ewes. Twenty-four crossbred ewes were randomly distributed in four treatments: (1) diet with 20%; (2) 40%; (3) 60%; and (4) 80% of concentrate. Animals were slaughtered when those receiving the diet with 80% of concentrate reached adult weight, at around 50kg LW. The data were analyzed by means of variance and regression analyses and correlations. The levels of concentrate increased live weight at slaughter linearly. Height at the withers and rump presented medium to high correlation (0.86). The correlation of loin eye area measured on the carcass and by ultrasound examination was 0.81, whereas for back fat thickness it was 0.85. The increase in the use of concentrate in the diets promotes heavier carcasses with better yields and fat cover. Some measures obtained in vivo presented high correlation with those measured on the carcass. The use of ultrasound can be a way to predict the in vivo loin eye area. The use of concentrate improves the meat quality in variables' color and appearance...

Objetivou-se avaliar o efeito de níveis crescentes de concentrado sobre as características quantitativas e qualitativas de carcaça de borregas confinadas. Vinte e quatro borregas mestiças foram aleatoriamente distribuídas em quatro tratamentos: (1) dieta com 20%; (2) 40%; (3) 60% e (4) 80% de concentrado. Os animais foram abatidos quando os que recebiam a dieta 80% de concentrado atingiram o peso adulto, ao redor de 50kg PV. Os dados foram analisados por meio de análise de variância e regressão e de correlações. Os níveis de concentrado aumentaram linearmente o peso vivo ao abate. A altura de cernelha e de garupa apresentaram correlação média a alta (0,86). A correlação da área de olho de lombo medida na carcaça e por meio de ultrassom apresentou valor de 0,81, enquanto a espessura de gordura subcutânea foi de 0,85. O aumento do uso de concentrado nas dietas proporciona carcaças pesadas e com melhores rendimentos e acabamentos. Algumas medidas feitas in vivo apresentaram alta correlação com as medidas na carcaça. O uso do ultrassom pode ser utilizado como forma de predição da área de olho de lombo in vivo. O uso do concentrado melhora a qualidade da carne nos parâmetros de cor e aparência...

Proteins differentially expressed by Shiga toxin-producing Escherichia coli strain M03 due to the biliar salt sodium deoxycholate.

Shiga toxin-producing Escherichia coli (STEC) can cause conditions ranging from diarrhea to potentially fatal hemolytic uremic syndrome. Enteropathogen adaptation to the intestinal environment is necessary for the development of infection, and response to bile is an essential characteristic. We evaluated the response of STEC strain M03 to the bile salt sodium deoxycholate through proteomic analysis. Cell extracts of strain M03 grown with and without sodium deoxycholate were analyzed by two-dimensional electrophoresis; the differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Three proteins were found to be differentially expressed due to sodium deoxycholate. Glycerol dehydrogenase and phosphate acetyltransferase, which are involved in carbon metabolism and have been associated with virulence in some bacteria, were downregulated. The elongation factor Tu (TufA) was upregulated. This protein participates in the translation process and also has chaperone activities. These findings help us understand strategies for bacterial survival under these conditions.