title: Effect of slaughter season and muscle type on the fatty acid composition, including conjugated linoleic acid isomers, and nutritional value of intramuscular fat in organic beef.
abstract: BACKGROUND
  Consumer awareness regarding the intake of beef of organic origin is strongly associated with the beneficial outcomes to human health, the environment and animal welfare. In this paper the effects of slaughter season and muscle type on the fatty acid composition, conjugated linoleic acid (CLA) isomeric profile, total cholesterol, α-tocopherol and β-carotene contents and nutritional quality of intramuscular fat in organic beef (n = 30) are reported for the first time.
  
  
  RESULTS
  Organic beef showed a very low total lipid content, with seasonal changes in the levels of some fatty acids, CLA isomers, n-6/n-3 polyunsaturated fatty acid (PUFA) ratio, total cholesterol and β-carotene. In addition, differences between longissimus lumborum (relatively red) and semitendinosus (relatively white) muscles were found for many fatty acids, specific CLA contents, many CLA isomers and both PUFA/saturated fatty acid (SFA) and n-6/n-3 ratios. However, in spite of the seasonal and carcass variations, all organic meats analysed had values of beef similar to pasture-fed cattle.
  
  
  CONCLUSIONS
  From a nutritional perspective, organic meat from both slaughter seasons seems to have high CLA contents, PUFA/SFA and n-6/n-3 indices within the recommended values for the human diet. The data indicate that intramuscular fat in organic meat has a high nutritional value throughout the year.
authors.affiliation: CIISA, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Lisboa, Portugal.
authors.forename: José M
authors.initials: JM
authors.lastname: Pestana
authors.forename: Ana S H
authors.initials: AS
authors.lastname: Costa
authors.forename: Susana V
authors.initials: SV
authors.lastname: Martins
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Alfaia
authors.forename: Susana P
authors.initials: SP
authors.lastname: Alves
authors.forename: Paula A
authors.initials: PA
authors.lastname: Lopes
authors.forename: Rui J B
authors.initials: RJ
authors.lastname: Bessa
authors.forename: José A M
authors.initials: JA
authors.lastname: Prates
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle; D002784:Cholesterol / Q000378:metabolism; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D043371:Fatty Acids, Omega-6 / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D058870:Food, Organic / Q000032:analysis*; D006801:Humans; D007536:Isomerism; D019787:Linoleic Acid / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000378:metabolism; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009753:Nutritive Value; D006109:Poaceae; D012621:Seasons; D019207:beta Carotene / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D044243:Linoleic Acids, Conjugated; D019207:beta Carotene; D002784:Cholesterol; D019787:Linoleic Acid