Carcass and meat quality of finishing Friesian steers fed the β-adrenergic agonist L-644,969

The effect of the β-adrenergic agonist L-644,969 on selected parameters of carcass and meat quality was examined in Friesian steers. Four groups of 18 steers were individually offered ad libitum a pelleted diet that contained 0, 0·25, 1·0, or 4·0 ppm L-644,969 for 12 weeks prior to slaughter. L-644,969 quadratically increased carcass weight (3·7, 9·3, and 8·5%, P < 0·001) and altered the distribution of lean meat such that a greater (0·3–5%; P < 0·01) proportion was in the more valuable cuts. There were no effects of L-644,969 on carcass-chill loss and on the water-holding capacity of the longissimus thoracis et lumborum (LTL) muscle. The intramuscular-fat concentration of the LTL was decreased (27–50%; P < 0·01) and the effects on muscle ultimate pH were small and commercially unimportant. Fibre-optic-probe measurements of the LTL indicated darker (P < 0·01) meat due to β-agonist treatment. L-644,969 increased the shear force required to cut through cooked muscle from the LTL (159%, 209%, and 217%, P < 0·001). It is concluded that L-644,969 treatment improved the quantity and distribution of lean in the carcass but impaired meat quality, primarily through a reduction in tenderness.     

Lipid and colour stability of M. longissimus muscle from lambs fed camelina or linseed as oil or seeds

Reduced-fat pork patties produced with the addition of Laminaria japonica powder were evaluated for the chemical composition, cooking characteristics and sensory properties. Reduced-fat pork patties containing L. japonica powder had significantly higher moisture, ash, carbohydrate content, yellowness, and springiness than the control sample (P<0.05). Protein and fat contents, energy value, lightness, redness, cooking loss, reduction in diameter, reduction in thickness, hardness, gumminess, and chewiness of the regular-fat (20%) control samples were significantly higher than reduced-fat pork patties containing L. japonica (P<0.05). The sensory evaluations indicated that the greatest overall acceptability in reduced-fat pork patties was attained at a L. japonica concentration of 1 or 3%. Pork patties with fat contents reduced from 20% to 10% and supplemented with 1 or 3% L. japonica had improved quality characteristics that were similar to the control patties containing a fat content of 20%.     

Designing feedback-based contrast enhancement for in vivo imaging

Objective: Nonlinear feedback interactions induced by the spins themselves have recently been introduced as novel MRI contrast enhancement mechanisms sensitive to small differences in MR parameters. Developing feedback-based contrast enhancement into a useful tool for in vivo imaging requires improved techniques that are robust to inhomogeneity and sensitive to subtle anatomical/physiological variations. Materials and methods: Three different imaging methods combining the radiation damping feedback field with the distant dipolar field, applied radio-frequency (RF) fields, and local dipole fields, respectively, were designed and tested through numerical simulations on simple phantoms. These methods were demonstrated experimentally on live guppy fish, developing frog embryos, and blood in in vitro tissue samples by microimaging at 14.1 T. Results: The developed feedback-based methods yielded images that identified distinct morphological features with superior contrast compared with conventional MR images and those acquired under radiation damping only. Positive contrast due to evolution under radiation damping and local dipole fields was also observed in SPIOs and blood. Conclusion: Approaches to enhancing feedback-based contrast were successfully designed and demonstrated in vitro and in vivo. The newly devised methods were less sensitive to field inhomogeneity and prolonged evolution under the feedback fields, allowing for better visualization of contrast in vivo.