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Open access

Joanna Stadnik, Anna Czech and Katarzyna Ognik

Abstract

In this study, the effect of the halved dosage of RRR-d-α-tocopherol (with respect to dl-α-to-copherol acetate) in diets containing oil rich in linoleic or α-linolenic acid (soybean or linseed oil, respectively) on the quality characteristics and fatty acid (FA) profile of turkey meat was studied. The experiment was conducted using 480 one-week-old turkey hens Big 6 line reared until the 16th week of life. The hens in Groups I and II received soybean oil added to their feed mixture, in Groups III and IV linseed oil was the source of supplementary fat. Turkeys in Groups I and III received dl-α-tocopherol acetate, whereas those in Groups II and IV RRR-d-α-tocopherol. No influence of dietary manipulation was observed on the chemical composition of turkey meat. The combined effect of the type of dietary fat and vitamin E source added to the feed was assessed using the color parameters. The addition of natural vitamin E to the feed mixture with linseed oil significantly increased the proportion of PUFA in breast muscle lipids compared with the group receiving soybean oil with this form of vitamin E. The inclusion of linseed oil increased the content of α-linolenic acid and total n-3 FA concentration in both muscles, compared with the diet that contained soybean oil. This modification of FA composition led to lower n-6/n-3 ratio in both the breast and thigh muscles regardless of the dietary vitamin E source. The use of natural form of tocopherol in diets containing linseed oil may help to improve the nutritional quality of turkey meat, especially by enhancing n-3 PUFA levels with no detrimental effect of lipid addition on the chemical composition and quality of meat.

Open access

Joanna Stadnik, Małgorzata Karwowska, Zbigniew Dolatowski, Małgorzata Świątkiewicz and Krzysztof Kwiatek

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.

Open access

Małgorzata Karwowska, Małgorzata Grabowicz, Joanna Stadnik, Piotr Szterk, Zenon Bernacki and Zbigniew J. Dolatowski

Abstract

The aim of this study was to assess the production parameters of White Koluda® geese fed with a corn or beet pulp silage supplemented diet. The oxidative stability of breast and thigh muscles during frozen storage and the fatty acid composition of abdominal fat were also investigated. Measurements were carried out on a total of 42 geese of the White Koluda® W31 strain that were divided into three experimental groups: group I (control) - basal diet, group II - basal diet with corn silage addition, group III - basal diet with pressed beet pulp silage addition. Diets containing ad libitum maize silage or sugar beet pulp silage supplemented with a limited amount of commercial diets, significantly reduced BW (about 9%) and ADG (about 27%) of birds compared to the control group in the 14th week of rearing. Feeding corn or sugar beet pulp silage to geese did not affect pH values, heme iron content, colour parameters but decreased lipid oxidation values in muscles 3 days after slaughter. The abdominal fat of geese fed with the pressed beet pulp silage supplemented diet was characterized by a significantly higher content of myristic and linoleic acid and a lower content of oleic acid. In conclusion, feeding geese with limited amount of commercial mixtures supplemented with maize or sugar beet pulp silages may be recommended primarily for increasing financial efficiency in White Koluda® geese farms but also for improving the quality of goose carcasses, due to their low fat and high quality of meat.