Effect of Genetically Modified Feeds on Physico-Chemical Properties of Pork

The objective of this study was to evaluate the effects of genetically modified (GM), insect-resistant Bt maize (MON810) and the meal made of glyphosate-tolerant soybean (Roundup Ready MON40-3-2) used as the dietary components for pigs on the physico-chemical properties of meat. Forty-eight fatteners derived from Polish Landrace x Polish Large White sows mated to a Duroc x Pietrain boar were used. All animals received isonitrogenous and isoenergetic diets containing or not containing the genetically modified components. The design of the experiment was as follows: group I (control) - non-modified soybean meal and maize; group II - GM soybean meal and non-modified maize; group III - non-modified soybean meal and GM maize; group IV - GM soybean meal and GM maize. The examination of the pH values of loin and neck muscles indicated no statistically significant differences between pigs fed diets containing non-transgenic or transgenic feeds. No statistical differences were observed for water holding capacity (WHC) within dietary treatments. The introduction of transgenic maize and soybean meal into pig diets did not significantly affect the a^* colour parameter of loin as well as neck muscles. The use of transgenic maize or soybean meal did not cause significant changes in the L^* colour value of loin. Results obtained for neck muscles were more differentiated, possibly due to the natural heterogeneity of this primal cut. Pigs which had consumed the transgenic diet exhibited slightly decreased lipid stability of loin, as indicated by thiobarbituric acid reactive substances (TBARS). The decrease was statistically significant only in the case of muscles from group II. The addition of feeds derived from genetically modified crops into pig diets did not significantly affect the stability of neck muscle lipids; however, TBARS values of these muscles were twice those of loin muscles.