Effect of diets containing n-3 fatty acids on muscle long-chain n-3 fatty acid content in lambs fed low- and medium-quality roughage diets.

Abstract

In two experiments, each with 32 cross-bred ([Merino x Border Leicester] x Poll Dorset) wether lambs (26 to 33 kg weight range), animals were randomly assigned to one of four treatments. A mixture of lucerne chaff:oaten chaff was used as a basal diet, offered in different ratios. Animals were allowed to consume on a free-access basis in Exp. 1 or 90% of ad libitum intake in Exp. 2 in order to provide a low- (6.5 MJ ME/d) and medium- (9.5 MJ ME/d) quality basal diet, respectively. Isoenergetic amounts of lipid supplements, fish meal (80 g DM), canola meal (84 g DM), and soy meal (75 g DM) were tested in Exp. 1. In Exp. 2, fish meal (9% DM), unprotected rapeseed (7% DM), and protected canola seed (6% DM) were fed as supplements. At the end of 53-d (Exp. 1) or 46-d (Exp. 2) experimental periods, lambs were slaughtered at a commercial abattoir and at 24 h postmortem longissimus thoracis (LT) muscle was collected for the analysis of fatty acid (FA) composition of structural phospholipid and storage triglyceride fractions. Fish meal diet increased LT muscle long-chain n-3 FA content by 27% (P < 0.02) in Exp. 1 and 30% (P < 0.001) in Exp. 2 compared with lambs fed the basal diet, but fish meal decreased (P < 0.01) the n-6 FA content only in Exp. 1. Soy meal and protected canola seed diets increased (P < 0.01) LT muscle n-6 FA content but did not affect long-chain n-3 FA content. Longissimus thoracis muscle long-chain n-3 FA were mainly deposited in structural phospholipid, rather than in storage triglyceride. In both Exp. 1 and Exp. 2, the ratio of n-6:n-3 FA in LT muscle was lowest (P < 0.01) in lambs fed fish meal supplement compared with all other treatments. Protected canola seed diet increased the ratio of n-6:n-3 FA (P < 0.01) and PUFA:saturated fatty acid (P < 0.03) content from those animals fed the basal, fish meal, and unprotected rapeseed diets in Exp. 2. This was due to an increase in muscle n-6 FA content, mainly linoleic acid, of both phospholipid (P < 0.001) and triglyceride (P < 0.01) fractions and not to an increase in muscle n-3 FA content. The results indicate that by feeding fish meal supplement, the essential n-3 FA can be increased while lowering the ratio of n-6:n-3 content in lamb meat to an extent that could affect nutritional value, attractiveness, and the economic value of meat.

Fatty acid profile and lambs’ meat quality fed with different levels of crude glycerin replacing corn

“…According to Osório and Osório (2003), the high total lipids can negatively affect meat product, once consumers have certain restrictions on the ruminants fat, mainly sheep, due to the high levels of saturated fatty acids. Studies have shown that the lipid levels of lamb meat can present great variation, especially when animals are subjected to distinct diets, such as the findings of Zeola et al (2004) using different concentrate levels (60, 45, and 30%), or diets containing different sources of roughage (PONNAMPALAM et al, 2001). However, in this study, the crude glycerin levels did not significantly affect meat lipids.…”

Physiological and biochemical response to Omega-3 plus as a dietary supplement to growing goats under hot summer conditions

“…Unfortunately, mammals have limited ability to synthesize omega-3 fatty acids, which are necessary for their health benefits (Kris-Etherton et al, 2002). It is well known that dietary omega-3 has an important role in the maintenance of the structure of cellular membranes, improving the absorption of liposoluble vitamins (A, D, E, and K), reducing plasma triglycerides, regulating the cholesterol metabolism, and producing eicosanoids, which regulate various cellular processes (vascular and bronchial tone, gastrointestinal and uterine motility, gastric protection, urine output, blood clotting, body temperature, and inflammatory and immune processes (Ponnampalam et al, 2001). Dietary omega-3 fatty acids are also essential for normal growth and metabolism (Kris-Etherton et al, 2002).…”

Avaliação sensorial da carne de cordeiros machos e fêmeas Texel × Corriedale terminados em diferentes sistemas

“…Além disso, nos ruminantes, parte dos ácidos graxos insaturados provenientes da dieta é saturada por meio de um processo de biohidrogenação no ambiente ruminal como forma de neutralizar o efeito tóxico desses ácidos graxos aos microrganismos ruminais. Como resultado desse processo, a classe dos ácidos graxos saturados é absorvida e incorporada ao nível de tecido muscular (Ponnampalam et al, 2001). Petrova et al (1994) salientaram que uma dieta à base de concentrado tem elevada quantidade de carboidratos rapidamente degradáveis no rúmen, fato que pode ter intensificado o gosto doce na carne dos cordeiros sob suplementação.…”