title: The effects of dietary fat sources, levels, and feeding intervals on pork fatty acid composition.
abstract: Two experiments investigated the quantitative relationship between dietary fat and fatty acid composition of pork. Experiment 1 was designed to establish the rate of decline for linoleic acid and iodine value of pork fat during the late fattening phase following a dietary reduction. Gilts (n = 288) were fed diets varying in linoleic acid content from 4.11 to 1.56% for 4, 6, or 8 wk prior to slaughter. The maximum rate of decline was 2% 18:2 per week and 2.5 iodine value units per week. Experiment 2 evaluated the effects of dietary fat source and level on carcass fatty acid composition and on pork quality characteristics. Barrows (n = 147) and gilts (n = 147) were allocated to seven dietary treatments for the last 6 wk of the finishing phase. Diets contained 0, 2.5, or 5% dietary fat comprised of 100, 50, or 0% beef tallow. The balance was provided by animal-vegetable blended fat. As the level of tallow increased there was a linear decrease (P < 0.05) in 18:2 content and iodine value of carcass fat. Conversely, 16:1 and 18:1 increased linearly (P < 0.05) as tallow increased. However, 16:1 decreased linearly (P < 0.05) as level of fat increased. As the level of tallow was increased a greater reduction in 18:2 and iodine value was observed in diets with 5% dietary fat compared to diets with 2.5% fat (P < 0.05). These results indicate that reduction of dietary PUFA content had the desired effect of lowering 18:2 content and iodine value of pork fat and that significant alterations could be elicited in as little as 6 to 8 wk of feeding.
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh 27695, USA.
authors.forename: L
authors.initials: L
authors.lastname: Averette Gatlin
authors.forename: M T
authors.initials: MT
authors.lastname: See
authors.forename: J A
authors.initials: JA
authors.lastname: Hansen
authors.forename: D
authors.initials: D
authors.lastname: Sutton
authors.forename: J
authors.initials: J
authors.lastname: Odle
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D001823:Body Composition / Q000235:genetics; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005223:Fats / Q000008:administration & dosage / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D005838:Genotype; D007455:Iodine / Q000032:analysis; D019787:Linoleic Acid / Q000032:analysis; D008297:Male; D008460:Meat / Q000032:analysis* / Q000592:standards; D011897:Random Allocation; D013552:Swine / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: D004041:Dietary Fats; D005223:Fats; D005227:Fatty Acids; D007455:Iodine; C013698:tallow; D019787:Linoleic Acid