Dietary supplementation of different plant extracts containing phenolic compounds in rabbits: performance and meat quality

Abstract

The present experiment studied the effect of dietary supplementations with oregano, rosemary and oregano+rosemary on rabbit growth performance and meat quality. Five groups of forty New Zealand White (NZW) weaned rabbits were submitted to the following dietary treatments: Standard diet (S); Standard diet +150 ppm vitamin E (E); Standard diet + 0.2% oregano extract (O); Standard diet + 0.2% rosemary extract (R); Standard diet + 0.1% oregano extract + 0.1% rosemary extract (OR). Each diet contained integrations of: 50 ppm vitamin E, CLA 0.5% (from soy oil), 3% Omega Lin® (Mignini & Petrini) and 0.5% mixed vitamins. Rabbits were slaughtered at 80 d of age and slaughter yield and carcass traits were determined. On Longissimus dorsi (LD) muscle, the ultimate pH was measured, the cooking loss and the Water Holding Capacity (WHC) were estimated, the L*, a* and b* color parameters and the antioxidant status (TBARs) were measured. The body weight, which was recorded at 80 days of age, was higher in O and OR groups (2344 g and 2368 g, P<0.05) compared to the other dietary treatments; O group recorded the best DWG (24.26 g/d, P<0.05), FCR (2.59, P<0.05) and carcass weight (1425 g, P<0.05). The best carcass yield was recorded for dietary groups integrated with aromatic essences. The S group showed the highest value for cooking loss (P<0.05), thus highlighting the importance of a dietary integration with antioxidants to preserve the integrity of the muscle membranes. Analyzing the color parameters, only the red index “a*” reached the statistical significance. Specifically, it showed the lowest values for O and OR groups, as it is desirable for rabbit meat. Concerning the oxidative stability of the meat, groups E and O showed lower MDA contants compared to the other dietary treatments (P<0.05). In conclusion, a dietary supplementation with natural extracts showed positive effects on rabbits’ performances and some meat quality parameters.