This work was undertaken to study the effect of dietary fat source on the fatty acid profile of pork, and to evaluate the effect of inclusion of vitamin E in pig diets on lipid oxidation of pork tissue and processed pork products. Fifty-six pigs were allocated to four treatments, that included two dietary fat sources and two levels of vitamin E inclusion. Dietary fat was derived from either tallow, a source of saturated fatty acids (SFA), or from a mixture of soybean and linseed oils, which contain polyunsaturated fatty acids (PUFA). Vitamin E was included at either 0% or 0.011% of the diet. Growth and carcass characteristics were not affected by the dietary treatments. Dietary fat source affected the fatty acid profile of the longissimus muscle and subcutaneous fat tissue, with the PUFA diet resulting in significantly more polyunsaturated fatty acids in the tissues, and more favourable ratios of SFA to PUFA and C18:2 to C18:3 in terms of human health considerations. Lipid oxidation was significantly greater in tissues and processed products from PUFA-fed pigs. Inclusion of vitamin E in the diets, however, reduced the extent of lipid oxidation in the meat and meat products. Dietary manipulation of the fatty acid profile of pigs is an effective means of altering the fat composition of pork in order to provide human consumers with a healthy product. Vitamin E is effective as an antioxidant agent, particularly where processed products are concerned.

BaciUlus thuringiensis was isolated from dried tobacco residues and dead tobacco beetles (Lasioderma serricorne (F.); Coleoptera: Anobiidae) collected in a large number of locations worldwide. Eighty-eight samples of stored tobacco were analyzed and yielded 78 B. thuringiensis strains which were characterized on the basis of parasporal crystal morphology, sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles, and the results of an immunoblot analysis of the insecticidal crystal proteins. Flagellar antigen identification was used to differentiate selected isolates. Strains that produced rhomboidal crystals associated with the Coleoptera-specific pathotype (Cry Ill group) were the most abundant strains (59%o of the isolates). Preliminary toxicity assays were performed with L. serricorne larvae, and the results suggested that activity is not restricted to isolates related to the Coleoptera-specific group. The results of our survey indicate that B. thuringiensis is part of the natural microflora in the stored-tobacco environment and that this special habitat represents a source of B. thuringiensis isolates that may be used to control stored-product pests.

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