Fatty Acid Composition and Eating Quality of Muscle from Steers Offered Grazed Grass, Grass Silage or Concentrate-Based Diets

The effects of grazed grass, grass silage or concentrates on the eating quality and fatty acid composition of intra-muscular fat of steers fed to achieve similar carcass growth rates were investigated. Fifty steers were assigned to one of five dietary treatments. The experimental rations offered daily for 85 days pre-slaughter were (a) grass silage plus 4 kg concentrate, (b) 8 kg concentrate plus 1 kg hay, (c) 6 kg grazed grass dry matter (DM) plus 5 kg concentrate, (d) 12 kg grazed grass DM plus 2.5 kg concentrate or (e) 22 kg grazed grass DM. Decreasing the proportion of concentrate in the diet, which effectively increased grass intake, caused a linear decrease in the concentration of intra-muscular saturated fatty acids (SFA) (P \u3c .01) and in the n-6 to n-3 poly-unsaturated fatty acids (PUFA )ratio (P\u3c .001) and a linear increase in the PUFA to SFA ratio (P \u3c .01) and the conjugated linoleic acid concentration (P \u3c .001). There was an interaction (p\u3c 0.05) between ageing time and treatment with treatment d having higher (p\u3c 0.05) tenderness, texture and acceptability values after 2 days ageing, but not after 7 or 14 days ageing. The data indicate that intramuscular fatty acid composition of beef can be improved from a human health perspective by inclusion of grass in the diet without any negative effect on the eating quality

An examination of the molecular mechanisms controlling the tissue accumulation of conjugated linoleic acid (CLA) in cattle

End of project reportLong chain n-3 polyunsaturated fatty acids (n-3 PUFA) and conjugated linoleic acid (CLA) have demonstrable and potential human health benefits in terms of preventing cancer, diabetes, chronic inflammation, obesity and coronary heart disease. Supplementation of cattle diets with a blend of oils rich in n-3 PUFA and linoleic acid have a synergistic effect on the accumulation of ruminal and tissue concentrations of trans vaccenic acid (TVA), the main substrate for ?-9 desaturase which is responsible for de novo tissue synthesis of the cis 9, trans 11 isomer of CLA. This dietary strategy translates into increases in milk concentrations of CLA in dairy cows; however, concentrations in the muscle of beef animals have not always been increased. There is an apparent paradox in that n-3 PUFA supplementation enhances ruminal synthesis of trans-vaccenic acid (TVA), but then inhibits its conversion to CLA possibly through altering the activity of ?-9 desaturase. Recently, the promoter regions of the bovine ?- 9 desaturase gene has been isolated and analysed and has been shown to contain a conserved PUFA response region

Developing a Diet Authentication System from the Composition of Meat in Ruminants

As consumer interest in the link between diet and human health and in the ethics of food production increases assurances about the background origin of food are sought. In the case of animal-derived foods, such as meat, the animal’s diet is an intrinsic component of the food’s production and of its subsequent nutritional quality. Thus, there is a need to develop ways of validating the authenticity of the animal diet. Among the approaches to authenticate the background diet of ruminants is the measurement of components in meat (muscle and adipose tissue) and other tissues that are directly influenced by the diet, including fatty acids, carotenoids, vitamins, volatile organic compounds and elemental stable isotope ratios, as well as measurement of indirect indices such as spectral properties. While each is useful in its own right, the reliability of different measurements, for diet authentication purposes, depends on the sensitivity of the analytes measured to changes in diet, and on tissue turnover in response to changes in dietary constituents. Of the analyses discussed, stable isotope analysis in muscle and incremental tissues is presented as a particularly powerful tool for diet reconstruction

Intake and Growth of Steers Offered Different Allowances of Autumn Grass and Concentrates

The aim of this experiment was to quantify the relationship between autumn grass supply and concentrate supplementation level on grass intake and animal performance. One hundred and ten continental steers (567kg) were assigned to ten treatments in a three grass allowances: (6, 12 and 18kg dry matter (DM) per head daily) by three concentrate levels: (0, 2.5 and 5kg/head/daily) factorial design with a positive control group offered concentrates ad-libitum. Grass allowance was offered daily and concentrates were fed individually. The experiment began on August 22 and all animals were slaughtered after a mean experimental period of 95 days. Grass allowance increased (P\u3c 0.001) complete diet digestibility only in the absence of concentrates and supplementary concentrates increased (P\u3c 0.001) complete diet digestibility only at the low grass allowance. Both offering animals supplementary concentrates (P\u3c 0.001) and increasing daily grass allowance (P\u3c 0.001) increased their carcass growth rate. Grazed grass supported only one third the carcass growth rate of supplementary concentrates per kg of DM eaten. As a strategy for increasing the performance of cattle grazing autumn grass, offering supplementary concentrates offers more scope than altering grass allowance

Nutritive Value for Finishing Beef Steers of Wheat Grain Conserved by Different Techniques

Wheat grain harvested at dry matter (DM) concentrations above 860 g/kg is slow to deteriorate during long-term storage. However, high moisture grain (HMG) ranging from below 600 to 750 g DM/kg is conserved on some farms in the form of anaerobic storage of acid-treated, rolled wheat (AR) and urea-treated whole-wheat (UN) (Stacey et al., 2003). This experiment quantified the nutritive value for beef cattle of standard wheat grain (propionic acid-treated and rolled:PR) compared to AR and UN at different levels of intake

On the generation and the nonlinear dynamics of X-waves of the Schroedinger equation

The generation of finite energy packets of X-waves is analysed in normally dispersive cubic media by using an X-wave expansion. The 3D nonlinear Schroedinger model is reduced to a 1D equation with anomalous dispersion. Pulse splitting and beam replenishment as observed in experiments with water and Kerr media are explained in terms of a higher order breathing soliton. The results presented also hold in periodic media and Bose-condensed gases.Comment: 18 pages, 6 figures, corrected version to be published in Physical Review

Ginzburg-Landau equation bound to the metal-dielectric interface and transverse nonlinear optics with amplified plasmon polaritons

Using a multiple-scale asymptotic approach, we have derived the complex cubic Ginzburg-Landau equation for amplified and nonlinearly saturated surface plasmon polaritons propagating and diffracting along a metal-dielectric interface. An important feature of our method is that it explicitly accounts for nonlinear terms in the boundary conditions, which are critical for a correct description of nonlinear surface waves. Using our model we have analyzed filamentation and discussed bright and dark spatially localized structures of plasmons.Comment: http://link.aps.org/doi/10.1103/PhysRevA.81.03385

Effects of Supplementary Concentrate Level and Separate or Mixed Feeding of Grass Silage and Concentrates on Carcass Tissue Colour Traits in Steers

The level of supplementary concentrates fed with grass silage and the method of feeding (separate or mixed) may affect carcass tissue colour in steers. The objectives were to determine the effects of (1) supplementary concentrate level with grass silage, and (2) separate or mixed feeding of silage and concentrates, on muscle and fat colour

A Multicriteria Assessment of Forage or Concentrate-Based Finishing Diets for Temperate Pasture-Based Suckler Beef Production Systems

This study evaluated the effect of contrasting ‘finishing’ diets on animal performance, meat nutritional value, land use, food-feed competition, farm economics and greenhouse gas (GHG) emissions in temperate pasture-based suckler weanling-to-steer beef systems. Post-weaning, eight-month-old, spring-born, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) Grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) - slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) - slaughter age, 24 months (SIL+GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) - slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated was used to parameterise a farm-level beef systems model. Measured concentrate DM intake was 1187, 606 and 0 kg/head, and average daily gain was 0.83, 0.72 and 0.62 kg for GRAIN, SIL+GRAIN and FORAGE, respectively. Direct (pasture) land use was lowest for GRAIN. FORAGE was more profitable and was the only net producer of human edible protein and energy/ha. GRAIN produced the lowest GHG emissions per animal and meat essential amino acid concentration. FORAGE was more favourable for GHG emissions per kg of net (produced vs. consumed) production of human edible protein. Muscle amino acid and saturated fatty acid concentrations did not differ between the production systems, but FORAGE had the highest muscle concentration of omega-3 poly-unsaturated fatty acids. Differences in muscle mineral concentration were small. In conclusion, there are inverse relationships between food-feed competition, land-use, economics and GHG emissions per unit of product among different systems

Generation and control of extreme-blue shifted continuum peaks in optical Kerr media

We demonstrate tunable, extremely blueshifted continuum in \u3bb=1.055 \u3bcm ultrashort laser pulse filamentation in silica. Close to threshold, the continuum appears as a single, isolated blue peak. The spectral position of the two supercontinuum components can be tuned and a regime with encompassing fundamental and second harmonic is possible to achieve. At higher energies, the continuum expands in bandwidth starting from the blue peak. The spectral dynamics and tunability are explained in terms of X-wave generation and intrafilament pulse splitting which may be controlled by modifying the input pulse focusing conditions