Oxidized oils and dietary zinc and α-tocopheryl acetate supplementation: effects on rabbit plasma, liver and meat fatty acid composition and meat Zn, Cu, Fe and Se content

Abstract

The effects of the addition of heated oils to feeds (3%, w/w) and the dietary supplementation with a-tocopheryl acetate (TA; 100 mg/kg) and Zn (200 mg/kg) on rabbit tissue fatty acid (FA) composition and on the Zn, Cu, Fe and Se content in meat were assessed. Heating unrefined sunflower oil (SO) at 558C for 245 h increased its content in primary oxidation products and reduced its a-tocopherol content. However, this did not significantly affect tissue FA composition. Heating SO at 1408C for 31 h increased its content in secondary oxidation products and in some FA isomers as c9,t11-CLA and di-trans CLA. This led to increases in di-trans CLA in liver and in t9,c12-18:2 in meat. The c9,t11-CLA was the most incorporated CLA isomer in tissues. The dietary supplementation with a-TA did not affect the FA composition of plasma, liver or meat. The cooking of vacuum-packed rabbit meat at 788C for 5 min reduced significantly but slightly its polyunsaturated FA content. The dietary supplementation with Zn did not modify the content of Zn, Fe or Se in meat, but it reduced its Cu content. On the other hand, it increased the content of some FAs in meat when SO heated at 1408C for 31 h was added to feeds.Keywords: heated oils, fatty acid composition, plasma, liver, meat Implications An animal's diet has an influence on the composition of its tissues, which can be used to improve the nutritional value of meat, for instance modifying its fatty acid (FA) composition or increasing its mineral content. Unsaturated fat products used in feeds are prone to oxidation that can occur both during their production process and their storage, leading to a high content of oxidation compounds and altering their FA profile. This might affect the tissue composition, and thus the meat nutritional value. We studied the influence of the addition of oxidized oils and minerals to rabbit feeds on the FA composition of its plasma, liver and meat and on its meat element content. IntroductionFatty acid (FA) composition of animal tissues can be modified by the type and amount of dietary fat (Wood and Enser, 1997). Dietary recommendations for humans suggest reducing the intake of not only fat and cholesterol but also saturated FAs (SFA) and trans FA, and increasing the intake of polyunsaturated FAs (PUFAs), mainly those from the n-3 series (Food and Nutrition Board, 2005). Therefore, in order to obtain more healthy meat, several unsaturated fat sources have been incorporated to feeds to nutritionally improve meat FA composition (Wood and Enser, 1997).However, unsaturated fat sources are prone to oxidation that can occur both at low and high temperatures. At low temperatures, for instance during storage of unsaturated fats at ambient temperature, lipid hydroperoxides (LHPs) increase until they reach a plateau, and then decompose into secondary oxidation compounds. At high temperatures, decomposition of LHP is faster and isomerization of FA is also favored, leading to the appearance of both geometric and positional FA isomers, as several trans FA and conjugate...

Use of recovered frying oils in chicken and rabbit feeds: effect on the fatty acid and tocol composition and on the oxidation levels of meat, liver and plasma

“…However, in some cases the addition of highly oxidized oils (Sheehy et al, 1993) produced greater alterations in the FA composition of meat and liver. In contrast, other studies in which intermediate (more realistic) levels of feed oil oxidation were assayed, also showed none or very few effects on the FA composition of meat (Sheehy et al, 1993;Jensen et al, 1997;Bou et al, 2005;Tres et al, 2010a). In general, it appears that tissue FA composition is not affected by the addition of oxidized fats to feeds when these fats are used at suitable doses and when they are below the cut-off limit established for discarding frying oils (Firestone, 1996).…”

Effect of oxidation state of dietary sunflower oil and dietary zinc and α -tocopheryl acetate supplementation on performance of fattening rabbits

“…Vegetable oils subjected to overheating conditions for a long time lead to a reduction in PUFA (Bou et al, 2005;Tres et al, 2010b;Blas et al, 2010) as oxidation is mainly addressed to double bonds, but also in an increase of volatile compounds that derived from hydroperoxy or alcoxy radical breakdown. In ruminants, vegetal oil addition has frequently been related to decreases in fibre digestibility due to the negative effect of PUFA and radicals on ruminal microbial population (Ikwnegby and Sutton, 1982;Chalupa et al, 1984).…”

Moderately Oxidized Oils and Dietary Zinc and α-Tocopheryl Acetate Supplementation: Effects on the Oxidative Stability of Rabbit Plasma, Liver, and Meat

“…Zn supplementation did not modify the RT content of meat from animals on OSO feed, but led to a slight increase in its FA content (Table 4) (32) and, thus, in its susceptibility to oxidation, as indicated by the shorter IT and TMAX and higher MAXLHP, final LHP, and AUC (Table 4). Conversely, Zn supplementation in feed containing PSO led to a slight decrease in meat FA content (32) and thus in meat susceptibility to oxidation ( Table 4). Zn supplementation did not alter the susceptibility to oxidation of meat from animals on the FSO diet.…”

“…More research is needed to ascertain why Zn supplementation altered rabbit meat FA content depending on the oxidation status of the oil added to feeds (32).…”