title: Physical meat quality and chemical composition of the Longissimus thoracis of entire and immunocastrated pigs fed varying dietary protein levels with and without ractopamine hydrochloride.
abstract: Physical and chemical attributes of the Longissimus thoracis (LT) of 96 PIC(©) entire (E) and immunocastrated (C) pigs were evaluated. The study followed a 2 × 2 × 3 factorial design where three diets of low, medium and high proteins (7.50, 9.79 and 12.07 g digestible lysine/kg) were fed either with (10mg/kg) or without ractopamine (RAC) for the last 28 days of growth. Vaccination of C occurred at 16 and 20 weeks and slaughtering at 24 weeks of age. The LTs were analysed for moisture, protein, fat and ash contents as well as CIE L*, a*, b* colour, drip loss, cooking loss and Warner-Bratzler shear force (WBSF). Various sex and protein interactions were observed for LT protein content, L* values and WBSF. Cooking loss was decreased in C and by the medium protein diet. Feeding RAC increased WBSF values, whilst decreasing a* and b* values. However, the differences observed are minor and might be considered negligible when evaluated by a consumer.
authors.affiliation: Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa.
authors.forename: T
authors.initials: T
authors.lastname: Needham
authors.affiliation: Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa. Electronic address: lch@sun.ac.za.
authors.forename: L C
authors.initials: LC
authors.lastname: Hoffman
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition; D002369:Castration / Q000379:methods*; D003116:Color; D003296:Cooking; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008460:Meat / Q000032:analysis*; D009812:Odorants; D064170:Paraspinal Muscles / Q000378:metabolism; D010627:Phenethylamines / Q000494:pharmacology*; D013314:Stress, Mechanical; D013552:Swine; D014611:Vaccination; D014867:Water / Q000032:analysis
chemical_list: D000318:Adrenergic beta-Agonists; D004044:Dietary Proteins; D010627:Phenethylamines; D014867:Water; C060897:ractopamine
keywords: Boar taint; Colour; GnRH; Improvac; Pork; Tenderness