The relationship between ultrasound measurements and empty body and carcass chemical composition was investigated. A 500-V real-time ultrasound with a 7.5-MHz probe combined with image analysis was used to make in vivo measurements to predict the empty body and carcass chemical composition of 31 female lambs of two genotypes, ranging in BW from 18.2 to 48.9 kg. Eleven ultrasound measurements of s.c. fat, muscle, and tissue depth were taken at four different sites (over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, at the 3rd sternebra of the sternum, and over the 11th rib, 16 cm from the dorsal midline). The single best predictor of empty body fat quantity and energy value was the s.c. fat depth over the 13th thoracic vertebra (r(2) = 0.904 and 0.912; P <0.01, respectively). Body weight was used with ultrasound measurements in multiple regression equations to establish the best independent variables combination for predicting chemical composition. Results showed that BW and two of the three ultrasound measurements (s.c. fat depth over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, and tissue depth over the 11th rib, 16 cm from the dorsal midline), explained 94.7 to 98.7% (P < 0.01) of the quantity of water and fat and the energy value variation in the empty body and carcass. Body weight per se was the best predictor of the quantity of protein, accounting for 97.5 and 96.8% (P < 0.01) of the variation observed in the empty body and carcass, respectively. The results of this study suggest that BW and some ultrasound measurements combined with image analysis, particularly subcutaneous fat depth over the 13th thoracic vertebra, allow accurate prediction of empty body and carcass chemical composition in lambs.
The relationship between ultrasound measurements and the empty body chemical composition of mature ewes was studied in two breeds. The breeds were a milk-producing breed Churra da Terra Quente-CTQ (n = 33; live weight 42.0 ± 7.3 kg, mean ± SD), and a meat breed Ile de France-IF (n = 23; live weight 60.7 ± 9.1 kg, mean ± SD). Fat and muscle depths were measured in the live animals by real-time ultrasound scanning (RTU; 7.5 MHz probe) over the 13th thoracic, and between the 3rd and 4th lumbar vertebrae, and total tissue depth over the 11th rib. Following slaughter, the carcass and non-carcass components of the empty body were combined and subjected to chemical analysis and assessment of energy value. Data obtained by RTU after image analysis was used to develop simple and multiple regression models for each breed. The traits most accurately estimated from single RTU measurements were the absolute values for fat content and energy value of the empty body. The respective coefficients of determination (R 2) for IF and CTQ ewes using subcutaneous fat depth over the 13th thoracic vertebra were 0.768 and 0.908 for fat, 0.821 and 0.900 for energy; and for measurements between the 3rd and 4th lumbar vertebrae were 0.845 and 0.911 for fat, 0.852 and 0.906 for energy. All these coefficients were significant (P < 0.01). The best prediction models included one to three RTU measurements and were better for CTQ ewes, where adjusted R 2 values ranged from 0.923 (P < 0.001) for water to 0.969 (P < 0.001) for protein, than for IF ewes, where the range was 0.394 (P < 0.01) for protein to 0.940 (P < 0.001) for fat. The results revealed good estimates of the fat and energy content of the empty body of both breeds and also good estimates of protein content for CTQ ewes, but poor estimates of protein content for IF ewes, with the best prediction models for each body component being different from each breed. Consequently, it is concluded that predictive models that are specific to the breed and circumstances of the study in which they are to be used will have to be established to have a practical application.
The objective of this study was to evaluate the preservative and upgrading potential of urea added to whole-crop triticale. Triticale, harvested at different growth stages according to Feekes' scale (10.51, 10.54, 11.1 and 11.2), was ensiled with four levels of urea (0, 30, 60 and 90 g kg −1 dry matter (DM)) and stored in plastic bags for 60 days. Data were analysed as a factorial design with growth stage and urea level as the main factors. Urea was extensively hydrolysed (more than 90% of added urea). Urea breakdown was not affected by urea level (P > 0.05) but decreased significantly with growth stage (P < 0.001). Microbial activity measured by pH, volatile fatty acid production and total non-structural carbohydrate concentration was significantly reduced by the urea level. Urea treatment significantly (P < 0.001) increased water-soluble and ammonium nitrogen; more than 85% of the added nitrogen was retained. Application of urea at a rate of 60 and 90 g kg −1 DM significantly (P < 0.05) reduced the neutral detergent fibre (NDF) content and increased (P < 0.05) the NDF and acid detergent fibre in vitro digestibility. Whole-crop triticale harvested at later growth stages (approximately 60% DM) can be effectively preserved and upgraded by ensiling with 60-90 g urea kg −1 DM.
Several chromogenic media for detecting coliform bacteria in water are commercially available including Coli ID medium (ID) (bioMérieux) and MUG Plus cefsulodin agar (MP) (Laboratorios Microkit, S.L.). Since little is known about the performance of these media, we have evaluated their usefulness for recovering Escherichia coli and other coliform organisms in groundwaters used for direct human consumption. Variance analysis of obtained data showed that no statistically significant differences in counts of E. coli and other coliforms on ID and MP media compared with reference methods. However, the evaluation of sensitivity and recovery efficiency of both media showed that the two chromogenic media were more sensitive and significantly more efficient (P = < 0.05) than reference medium for detecting coliforms in groundwater. However, the identification of 400 typical and atypical colonies isolated from ID and MP media demonstrated a higher specificity when using ID for coliforms and E. coli. In summary, the two chromogenic media evaluated could be used as alternative methods to reference media for detecting and recovering coliform bacteria in groundwater samples. MP agar was more sensitive and efficient than ID agar whereas the latter was more specific and selective.
Culture methods for the detection of indicator bacteria are currently used for detection of waterborne bacteria. The need for an increased range of analyzed bacteria coupled with the obtainment of rapid and early results justify the development of a DNA microarray for the identification of waterborne pathogens. This DNA microarray has 16 implanted probes with a median size of 147 bases, targeting 12 different parameters, including all mandatory indicator microorganisms, such as Escherichia coli, Clostridium perfringens, Pseudomonas aeruginosa, Staphylococcus aureus, total and fecal coliforms and enterococci. The validation performed with DNA extracted from pure microbial cultures showed the suitability of the probes for detection of the target microorganism. To overcome the high dilution of water samples it was included either a prior culture step of bacterial contaminants retained after filtering 100 ml of water, or a 10-fold increase in the volume of filtered water, that resulted in the increase of the detected bacteria. The analysis of complex environmental water samples using culture methods and the DNA microarray revealed that the latter detected the same parameters plus other bacteria tested only in the DNA microarray. The results show that this DNA microarray may be a useful tool for water microbiological surveillance.
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