Effect of rearing system and genotype on performance, carcass characteristics and meat quality of slow growing rabbits

Introduction - The conservation of local rabbit breeds, characterized by slow growth, is very important for organic farming, because in most cases production regulations prohibit the use of commercial hybrids. Aim - The aim of this study was to investigate the effect of two different housing systems on the productive performance, carcass characteristics and meat quality of the local grey coloured rabbit population of Tuscany (middle-west Italy) compared to commercial hybrids. Material and methods - 88 rabbits of local populations were housed in colony cages, in open air (GO) organic rearing system; 84 rabbits of the same autochthonous populations (GI) and 80 hybrids (HI) were housed in colony cages in conventional rearing system. An organic diet, composed by pelleted feed and alfalfa hay, was given ad libitum. Thirty animals of each group were slaughtered at 103 days (autochthonous) and 90 days of age (hybrids), and carcass and meat quality parameters were assessed. Results and discussion - The HI group showed the lowest live weight at slaughtering age, the poorest productive performance and the highest mortality. GI group showed the highest live weight and more favorable feed conversion ratio compared with GO group. GO and GI groups showed higher hot carcass and dressing out percentage and lower incidence of full gastrointestinal tract percentage than group HI. Hind leg meat-to-bone ratio was significantly higher in HI group than in GO and GI groups (4.7% vs. 4.0% and 3.8%, respectively; P<0.05). The lowest muscular acidification was found in group GO (pHu=5.79 vs. 5.59 and 5.63, for group GO, GI and HI, respectively; P<0.05). The muscles of GO group showed lower lightness (L*) than the other groups (GO = 54.4 vs. GI = 59.1 vs. HI = 63.4; P<0.05). The GO and GI groups showed higher redness and yellowness than HI group. Chemical composition and lipid oxidation did not show differences due to genotype or housing system. As far as fatty acid content concerns, differences were found only for miristic and vaccenic acid between GO and HI groups. Conclusions - The local rabbits yielded more coloured meat, which could add value for potential consumers, independently of the rearing system used in the study.