Changes in texture, colour and fatty acid composition of male and female pig shoulder fat due to different dietary fat sources.

Two experiments with 72 slaughter pigs in each were conducted. Entire males and females were individually fed restricted. Palm kernel-, soybean- and fish-oil were used in varying combinations, giving different dietary fat levels (29-80g/kg) and iodine values ranging from 50 to 131. Shoulder fat was analysed for fatty acid composition (inner and outer layer), firmness and colour. A clear dose-response relationship was seen between fatty acids in diets and in shoulder fat. Interestingly, the very long chain n-3 fatty acids seemed to be deposited more efficiently when additional fat was included in the diet. Both high and low dietary iodine values changed towards less extreme iodine values in fat. Low-fat diets enhanced de novo synthesis of fatty acids. Males revealed a higher percentage of PUFA and a lower percentage of C18:1 and MUFA. Fat firmness, but not colour, was influenced by sex and dietary fat source.

Sensory quality of short- and long-term frozen stored pork products. Influence of diets varying in polyunsaturated fatty acid (PUFA) content and iodine value.

Predicting aspects of pork quality is becoming increasingly important from a nutritional as well as a technological point of view. Here, the influence of increasing PUFA and iodine values (IV) in feed and pigs on sensory qualities of short- and long-term frozen stored products was investigated. Entire male and female grower-finisher pigs were fed diets with iodine value products of 48 (LowIVP), 77 (MedIVP) or 99 (HighIVP) according to a restricted feeding scale. Ribs, chops and meat balls were short- (0-3 months) and long-term (6-9 months) frozen stored before sensory profiling. C18:2n-6 increased linearly in backfat with increased dietary inclusion. No negative effect on sensory quality was found in short-term stored products. After long-term storage the lean chops was the product most affected. Increasing the dietary IVP led to an increased rancid and total odour and flavour intensity, and to reduced meat and sour odour and flavour.

Fish oil in feeds for entire male and female pigs: changes in muscle fatty acid composition and stability of sensory quality.

A total of 72 crossbred [(Norwegian Landrace x Yorkshire) x Duroc] male and female growing-finishing pigs were restrictedly fed diets containing fish oil to study the fatty acid composition of Musculus longissimusdorsi and sensory quality of belly and neck. Six diets were used: two low-fat diets with or without 0.5% fish oil added, and four medium-fat diets with palm kernel oil to fish oil in ratios given as % inclusion: 4.1:0.0, 3.9:0.3, 3.6:0.5 and 3.4:0.7. Feeding fish oil gave a dose-dependent response between fatty acids in the diets and in the M.longissimusdorsi and increased the level of very long chain n-3 fatty acids, especially the C22:5n-3 (DPA). A more efficient n-3 fatty acids deposition was obtained when given as a medium-fat diet rather than the low-fat diet. Female pigs had a significant higher percentage of monounsaturated fatty acids and C18:1 than males suggesting a gender related difference in the delta-9-desaturase activity. No significant differences were found in sensory attributes for short-term stored neck and belly. For pigs fed the highest level of fish oil (0.7%) long-term stored (12 months at -80 degrees C, 6 months at -20 degrees C) belly showed a slight increase in fish oil flavour. After warmed-over treatment, fish oil odour and flavour as well as rancid flavour were increased in this group. The results suggest levels of dietary fish oil up to 0.5% produce a healthier meat fatty acid composition, without negative effects on sensory attributes, even in long-termed stored belly.