Natural-source vitamin E in pig meat

Dietary supplementation with vitamin E is an efficient approach to maintaining meat quality during storage because it effectively reduces the rate of lipid oxidation within the tissue. Tissue α-tocopherol is not degraded during storage or cooking, and the protective effect of endogenous α-tocopherol is ongoing during the storage and processing of meat and meat products (Jenssen et al., 1998). Natural-source vitamin E is derived from vegetable oils and exists in the form of RRR-α- tocopherol. Synthetic vitamin E, all-rac-α-tocopherol, consists of equal amounts of eight isomers, i.e., the RRR-, RRS-, RSR- and RSS- stereoisomers, the 2R forms, and the SRR-, SRS-, SSR- and SSS-stereoisomers, the 2S forms. Not all of these stereoisomers are equally bioavailable to animals. The natural form, RRR- α-tocopherol, has the highest bioavailability. Other 2R forms are bioavailable, but to a lesser extent than RRR-α-tocopherol; the 2S forms are not bioavailable. Animals preferentially retain RRR-α-tocopherol in tissues over the synthetic forms of vitamin E, resulting in higher α-tocopherol deposition in the muscle. α-Tocopherol deposition in the tissues of pigs was 2–3 times higher with natural-source vitamin E than with synthetic vitamin E when these forms of vitamin E were fed at the same level (Dersjant-Li and Peisker, 2010). The stable forms of vitamin E, i.e., RRR-α-tocopheryl acetate and all-rac-α-tocopheryl acetate, are commonly included in livestock diets.

The effects of different forms of vitamin E on the lipid oxidation of pork during storage were assessed (Boler et al., 2009). One hundred and fifty pigs were allocated to six treatments with six pens per treatment. The following diets were fed for 95 d before slaughter: 10, 40, 70, 100 and 200 mg/kg RRR-α-tocopheryl acetate and 200 mg/kg all-rac-α-tocopheryl acetate.

Carcass characteristics and lipid oxidation (assessed using thiobarbituric acid reactive substances [TBARS]) in loin chops and ground pork during storage were measured.

Supplementation with 40 mg/kg of natural-source vitamin E reduced lipid oxidation to the same extent as supplementation with 200 mg/kg of synthetic vitamin E (Table 1). An increase in natural-source vitamin E inclusion from 40 to 200 mg/kg numerically reduced TBARS. Carcass characteristics such as percentage lean, back fat thickness and loin depth were not affected by the treatments.

Natural-source vitamin E is more efficiently retained in the muscle than synthetic vitamin E and is more effective in reducing the rate of lipid oxidation, which may contribute to an extended meat shelf-life. Dietary supplementation with 40 mg/kg of naturalsource vitamin E is as effective as supplementation with 200 mg/kg of synthetic vitamin E.

Boler DD, Gabriel SR, Yang H, Balsbaugh R, Mahan DC, Brewer MS, McKeith FK, Killefer J (2009) Effect of different dietary levels of natural-source vitamin E in grow-finish pigs on pork quality and shelf life. Meat Science 83, 723-730.

Dersjant-Li Y, Peisker M (2010) A critical review of methodologies used in determination of bioavailability ratio of natural and synthetic vitamin E. Journal of the Science of Food and Agriculture 90,1571-1577.

Jensen C, Lauridsen C, Bertelsen G (1998) Dietary vitamin E: quality and storage stability of pork and poultry. Trends in Food Science and Technology 9, 62-72.

Table 1. Effect of various levels of natural-source vitamin E (NSE; ppm) on thiobarbituric acid reactive substances (mg/kg) in ground pork and loin chops, in comparison with synthetic vitamin E (Syn E; ppm).

Values are least square means for 36 pigs; Row means without common superscript letters differ significantly (P < 0.05).

This paper was presented at the recent Advances in Animal Nutrition, Australia Volume 18 (93). Engormix.com thanks the author and the organizing committee for this contribution.