Enhancing the eating quality of concentrate fed lambs

Hamo, R. (2019) Enhancing the eating quality of concentrate fed lambs. Doctoral thesis, Harper Adams University.

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Abstract

Two studieswere carried out to investigate the effect of dietary concentrate carbohydrateand fat source,and vitamin E level on animal performance, carcass composition and meat quality of concentrate fed lambs. In the first study, forty Suffolk cross Texel ewe lambs were blocked by live weight(LW)into four treatments (ten lambs /treatment): Grazed grass (G), barley based concentrate (B), dried grass based concentrate (DG) and sugar beet based concentrate (SB). The three concentrate diets were formulated to provide a similar level of crude protein, ether extract and an effective rumen degradable protein/fermentable metabolisable energyratio >10.0 g/MJ. Diets DG and SB provided a similar water soluble carbohydratecontent, but different proportions of neutral detergent fibre, whereas,in diet B the energy was supplied mainly as starch. Diet B contained Megalac©(rich in saturated fatty acids), whereasdiets DG and SB contained linseed oil (high in C18:3n-3). Diet B was formulated to contain 60 mgvitamin E (α-tocopherol-acetate)/kg DM,and diets DG and SB to contain 250 mgvitamin E (α-tocopherol-acetate)/kg DM. Lamb performance on diet G was lower than that of those fed the concentrate diets. Concentrate carbohydrate source, fat source and vitamin E concentration did not affect animal performance, carcass composition orcarcass measurements. Lambs fed diets DG orSB had a similar muscle C18:3n-3, C20:5n-3, cis-9, trans-11 CLA, n-6:n-3, C18:2n-6: C18:3n-3 and vitamin E content to those finished on grass. Lambs fed on eitherthe grass orconcentrate diets had similar lipid stability and sensory evaluation characteristics. In the second study, forty Suffolk cross Texel wether lambs were blocked and allocated by live weight to one of four treatments: Grazed grass (FG) or one of three iso-energetic and iso-nitrogenous diets, based on barleythat contained Megalac©with250 mgvitamin E (α-tocopherol-acetate)/kg DM (BML), or linseed oil attwo levels of vitamin E 250 (BLL) and 500 (BLH) mg/kg DM. Lambs fed the concentrate dietshad a higher live weight gainthan those finished on grass. Concentrate fat source andvitamin E level did not affect lamb performance, althoughlambs finished on BLH tended to have a lower feed conversion ratio compared to those fed diet BLL. Compared to lambs fedBML, the C18:3n-3, C20:5n-3 and C22:6n-3 content of longissimus dorsimuscle from lambs fed dietsBLL orBLH were increased, although, cis-9, trans-11 CLA waslowcompared to lambs fed diet FG or those diet DG (experiment 1). Muscle derived from lambs finished on BML or BLH had an enhanced shelf life (colour and lipid stability) compared to those fed BLL or FG. Neither grass nor concentrate diets affected the sensory attributes of lambsasperceived by consumers.Overall, the meat quality of concentrate fed lambs can be improved by inclusionof linseed oil with supra-nutritional vitamin E.

Item Type: Thesis (Doctoral)
Divisions: Animal Production, Welfare and Veterinary Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 15 Nov 2019 14:53
Last Modified: 15 Nov 2019 14:53
URI: http://hau.repository.guildhe.ac.uk/id/eprint/17464

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