Abstract

KLEIN JUNIOR, M.H.; SIQUEIRA, E.R.  and  ROCA, R.O.. Tissue composition and fat quality of meat of intact or castrated male lambs confined under two photoperiods. Arq. Bras. Med. Vet. Zootec. [online]. 2008, vol.60, n.2, pp. 461-469. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352008000200028.

The effects of photoperiod and castration on tissue muscle composition, fat physical-chemical composition, and cholesterol was determined for two muscles of 20 Ideal crossbred lambs. The animals were divided into four treatments: five intact males and five castrate during a short photoperiod of 12 light hours, and five intact males and five castrated during a long photoperiod of 18 light hours. The animals were allocated in individual pens, in two identical rooms, with light intensity of 300 lux, (intact and castrated animals x short and long photoperiod). The animals were slaughtered as they reached 37kg of body weight. Castrated lambs showed a significantly higher amount of total fat tissues while intact animals showed higher connective tissue for the shoulder tissue composition. Effect of castration on ash, lipid, and protein was observed in the subcutaneous fat tissue. Interaction effect between LF and castration promoted in shoulder fat intermuscular tissue increase of moisture content while the castration increased the lipid content and decreased the ash. Castrated animals presented higher intramuscular fat. Castrated lambs showed cholesterol contents in shoulder muscles larger than in the Longissimus lumborum muscle. The castration promoted larger amount of saturated fatty acids.

Keywords : castration; chemical analysis; fat; lamb; photoperiod; tissue.