Abstract :
The objective of the study was to evaluate the effect of genotype and the dietary fibre
concentration in the chemical composition and physical properties of lamb meat. Samples
from 54 animals from Morada Nova and Santa Inês native breeds and Dorpper×Santa Inês
half-breedwere analyzed, which received two diets, one with 41.7% and another with 33.6%
fibre content, until reaching the average slaughterweight of 30 kg. The design usedwas fully
randomized 3×2 factorial, three genotypes and two diets with nine replicates. Colour and
pH in Semimembranosus muscle were determined, together with the analyses of the water
retention capacity, loss of weight due to cooking, shearing force, and chemical composition
in Longissimus dorsi muscle. The factor genotype influenced the chemical composition of
meat, with Santa Inês lamb and crossbreed showing the highest protein percentages. The
diet with 33.6% fibre content provided meat with higher moisture percentage and lower
protein value, and the loss of weight due to cooking and shearing force parameters did not
interfere in other variables. In addition, lambs receiving higher fibre content diet produced
meat with lower shear force values, having indicated to be more tenderness. Despite these
variations, the meat of lambs from all genotypes and under the diets evaluated can be
considered of good quality.
