Facing climate change implications on feeds unavailability, unconventional resources are being considered with a growing interest such as aromatic plant distillation residues with a two-fold object, enhancing meat quality by increasing the antioxidant properties and reducing feed prices which are often imported though expensive. Hence, this study aims to assess the effects of rosemary distillation residues (RR) incorporation in concentrate associated to two nitrogen sources as a substitute for standard concentrate on lamb's growth, carcass traits and meat quality. For this, 24 Barbarine male lambs (3 months old, 17.83 ± 2.6 kg body weight) were divided into three groups. All lambs received individually 600 g of oat hay as roughage and 600 g of standard concentrate for control group, 600 g of concentrate based on RR and soybean meal for RRS group and 600 g of concentrate based on RR and faba bean for RRF group. After 65 days of experiment, all lambs were slaughtered. Phenolic and tocopherol intakes were significantly higher for both RR groups compared to control (p < 0.05). Growth, carcass weights, dressing percentages and non-carcass component weights were unaffected by the diet (p > 0.05). Moreover, regional and tissular compositions and meat physical properties were similar irrespective of the diet (p > 0.05). All color parameters were similar among groups (p > 0.05). However, meat produced by lambs receiving RR-based concentrate was richer on vitamin E and polyphenol contents than control lambs (p < 0.05). Rosemary by-products may substitute the standard concentrate resulting in similar lamb's growth and carcass traits, while improving meat quality by increasing vitamin E content, which could improve its antioxidant power.
Keywords: carcass characteristics; lambs; meat quality; rosemary residue; vitamin E.