Effects of dietary polysavone supplementation on performance and meat quality of growing rabbits

Introduction: The use of antibiotic feed additives has been banned in the European Union (EU) and ongoing discussions to restrict their use outside the EU is debated. At present, the use of plant extracts evidenced great interest and among them polysavone, extracted from alfalfa (Medicago sativa L, APS), showed interesting biological effects. Previous studies have shown that APS decreases abdominal fat deposition, enhance immunity and antioxidant function and seems to be beneficial for the growth of broiler chickens [1-2]. Considering these features observed on birds, the potential efficacy of APS to improve performance and meat quality of growing rabbits has been tested in an in vivo experimental trial. Material and methods: One hundred and sixty crossbred (Grimaud x Monferrato Grey) weaned rabbits (41-day-old) were kept in individual cages and divided into four groups of forty animals with an initial mean weight of 1123±160g. Rabbits were fed ad libitum with a basal diet (APS0) tested against three isonitrogenous and isoenergetic diets supplemented with 400, 800 and 1200 mg/kg of APS (APS4, APS8 and APS12, respectively). Performance data were recorded over 58 days. At 100 days of age, 12 rabbits per group were slaughtered and carcass characteristics and meat traits (pH, colour) were recorded. Moreover, on Longissimus dorsi muscle samples, lipid oxidation was studied at 30 days of frozen storage by TBARS assay. All data were analyzed by One-way ANOVA and differences of means by Duncan's test. Significance was set at p<= 0.05. Results and discussion: No significant differences were recorded for performance and carcass characteristic parameters. Dietary APS supplementation significantly (p=0.00) affected TBARS values of frozen meat with the lowest value (0.24 mg MDA/kg fresh meat) recorded in samples of the APS12 group. Conclusion: The results suggest that APS supplementation did not affect neither the growth performance parameters nor carcass characteristics. On the other hand, APS supplementation improve the muscle oxidation stability lowering the TBARS values in a dose-related manner. References: [1] Dong, X.F et al. Effect of polysavone (alfalfa extract) on abdominal fat deposition and immunity in broiler chickens. 2007. Poultry Science, 86:1955-1959.[2] Dong, X.F et al. Effects of dietary polysavone (Alfalfa extract) and chlortetracycline supplementation on antioxidation and meat quality in broiler chickens. 2011. British Poultry Science, 52:302-309.