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Enriching chicken meat with the long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) 20:5 (EPA) and 22:6 (DHA) by the inclusion of fish oil in the poultry diet is a means of increasing the human consumption of these essential fatty acids. However, a potential drawback of this practice is the adverse effect this can have on the sensory characteristics of chicken meat. Although freshly cooked meat may still be acceptable, oxidative stability of cooked and refrigerated meat from birds fed diets containing more than 40 g/kg fishmeal can be greatly diminished due to the development of unacceptable flavours in the cooked meat when it is reheated (O’Keefe et al., 1995). However, increasing the vitamin E content of the poultry diet increases the oxidative stability of the meat (Nam et al., 1997). The objective of this experiment was to determine the effects on LC n-3 PUFA content and sensory characteristics of white chicken meat when the inclusion rates of vitamin E and fish oil were increased in broiler diets.
The benefits to human health from consuming the very long chain n-3 polyunsaturated fatty acids (VLC n-3 PUFA) 20:5 (EPA) and 22:6 (DHA) are well known. In the human diet, oil-rich fish is a key source of VLC n-3 PUFA but fish consumption is so low that VLC n-3 PUFA intake is well below the minimum recommended. Other vehicles for increasing dietary supply have been explored and chicken meat is a potentially important contributor to human intakes if it is enriched with VLC n-3 PUFA, as it is responsive to dietary manipulation and is widely consumed. Enrichment of chicken meat can be achieved by supplementing the diets of growing birds with fish oil. However, reliance upon fish oil for this purpose is potentially unsustainable and the meat that is produced is more susceptible to constraints associated with its oxidative stability and organoleptic properties. Alternative sources of these fatty acids include marine algae (the primary producers of VLC n-3 PUFA) and fish oil encapsulated in a gelatin capsule. Both of these alternatives may increase the VLC n-3 PUFA content of the meat and also enhance its oxidative stability compared with meat that has been enriched by the inclusion of fish oil in the broiler diet. The objective of this study was to compare different sources of VLC n-3 PUFA in the broiler diet in relation to their effects on EPA and DHA concentration of the white and dark meat of the chicken.
Enriching chicken meat with the very long chain n-3 polyunsaturated fatty acids (VLC n-3 PUFA) 20:5 (EPA) and 22:6 (DHA) is a possible means of increasing the human consumption of these essential fatty acids as current levels of intake of these fatty acids are extremely low. However, a potential drawback of increasing the VLC n-3 PUFA content of chicken meat is that the oxidative stability of the meat is reduced. Chicken meat is enriched with VLC n-3 PUFA by the addition of fish oil to the chickens’ diet. It is possible that using alternative dietary sources of VLC n-3 PUFA may increase the oxidative stability of the meat (Mooney et al., 1998). The objective of this experiment was to determine what the source of VLC n-3 PUFA in broilers’ diets had on the oxidative stability of their edible tissues.
Enriching chicken meat with the very long chain n-3 polyunsaturated fatty acids (VLC n-3 PUFA) 20:5 (EPA) and 22:6 (DHA) is a possible means of increasing the human consumption of these essential fatty acids as current levels of intake of these fatty acids are extremely low. However, a potential drawback of increasing the VLC n-3 PUFA content of chicken meat is that the oxidative stability of the meat is reduced. PUFA are more oxidatively unstable than monounsaturated or saturated fatty acids, and the aldehydes produced by the n-3 PUFA during autoxidation have a lower taste threshold, and are much more unpalatable, than the aldehydes associated with autoxidation of the n-6 series of PUFA. The objective of this study was to determine what relationship there was between the fatty acid profiles of chicken meat that had been enriched (by dietary means) with VLC n-3 PUFA and the volatile aldehydes that were produced by the meat after it had been cooked.
Sustainable ruminant livestock systems must promote an efficient use of resources for food production and minimise their environmental impact. Intensive dairy cow production, based on grass silage, is a major contributor to nitrogen (N) loss to the environment, estimated as 18.2 t N/t milk for grass silage-based diets (Delaby et al., 1995). It is widely accepted that this low efficiency (milk N/dietary N) value reflects the low efficiency of capture in the rumen of the extensively degraded N fraction in grass silage (Givens and Rulquin, 2004). A common feature of plant tannins is their capacity to bind proteins and an improvement in N utilisation by ruminants has been reported for a number of tanniniferous feeds (Mueller-Harvey, 2006). Therefore, the aim of the present experiment was to study the potential of various commercial non-toxic tannin products to reduce proteolysis during ensilage.
A reduction of the overall nitrogen (N) loss to the environment from intensive ruminant production systems remains a key policy and research objective. Such an outcome is essential for the development of sustainable ruminant farming systems that minimise their environmental footprints. Plant and microbial enzyme-mediated proteolysis during ensilage results in the extensively hydrolysed N fraction in grass silage (Givens and Rulquin, 2004). It is generally accepted that the highly soluble N fraction of grass silage is poorly utilised by ruminants, reflecting the low efficiency of capture of silage N in the rumen. An improvement in dietary N efficiency by ruminants is therefore a key concern. Plant tannins have in common their capacity to bind proteins and an improvement in N utilisation by ruminants has been reported for a number of tanniniferous feeds (Mueller-Harvey, 2006). Therefore, the aim of the present experiment was to study a by¬product from the wine industry, so-called ‘grape marc’, as a potential source of tannins to reduce proteolysis during ensilage.
The health benefits of consuming sufficient very long chain n-3 polyunsaturated fatty acids (VLC n-3 PUFA) such as EPA (C20:5) and DHA (C22:6) are well established. A key supplier of these fatty acids is oil-rich fish, however a recent study relating to UK adults indicated that only 27% of the population consume oil-rich fish and current intakes of VLC n-3 PUFA are substantially sub-optimal (Givens and Gibbs, 2006). There is also evidence to indicate that in vivo conversion of alpha linolenic acid (C18:3 n-3) to EPA and DHA is limited and highlights the need for an increased supply of preformed EPA and DHA in the diet. The role of animal-derived foods in the supply of VLC n-3 PUFA has been identified and emphasis has been placed on the need to enrich foods such as poultry meat which are widely consumed in order to make a valuable contribution to the supply of EPA and DHA to those with low or zero oil-rich fish consumption. However the effect of age and gender on intakes remained unclear. The objective of this study was to investigate the effect of age and gender on oil-rich fish consumption.
The nutritional benefits of consuming long chain n-3 polyunsaturated fatty acids (PUFA), which are predominantly found in oily fish, are well known but consumption of oily fish is declining. Poultry consumption, on the other hand, is increasing, but poultry meat is generally a poor source of long chain n-3 PUFA. The concentrations of the n-3 PUFA α-linolenic acid (LNA), EPA and DHA in poultry meat may be increased by feeding birds diets that are themselves rich in these acids. The objective of this study was to review the literature to determine what relationship if any there was between n-3 PUFA content in the diet and edible tissues of poultry.
One of the richest sources of commercially available home grow protein is rapeseed meal (RSM), but its inclusion in livestock diets is approximately half that of soyabean meal (SBM, DEFRA statistics). Compared with SBM, both protein content and quality in RSM is inferior, but it is possible that particular varieties of rapeseed, together with an appropriate protocol for the extraction and subsequent treatment of rapeseed meal, may reduce the difference in the nutritive value of RSM and SBM. This would make the inclusion of larger amounts of RSM in livestock diets more attractive. The objective of this experiment was to determine how great the variation in the chemical composition and predicted amino acid availability for poultry of RSM was when prepared from modern UK varieties of rapeseed.