EFFECT OF DIETARY SUPPLEMENTATION OF CHESTUNT HYDROLISABLE TANNIN ON DIGESTIVE EFFICIENCY, GROWTH PERFORMANCE AND MEAT QUALITY IN GROWING RABBITS

The aim of the study was to evaluate the effect of the dietary supplementation of chestnut hydrolysable tannin on the feed digestibility and nutritive value, mortality and growth performance, fatty acid profile and TBARS of cooked Longissimus dorsi (LD) meat. From the age of 18 days the rabbits were fed pellets supplemented with coccidiostat (CC) or with tannin (400 g/100 kg: T400). At weaning (35 d of age) within both groups 5 dietary sub-groups were formed: medicated-free (C0), containing coccidiostatic (CC), or supplemented with increasing levels of chestnut tannin (T200, T400 and T600). Rabbits fed the 5 diets ad libitum until slaughter at 11 weeks of age. The coefficient of total tract apparent digestibility (CTTAD) of nutrients was not affected by the tannin inclusion, substantially, with exception of CTTAD of hemicelluloses, that was lower in T400 and T600 compared to C0 and T200 (P<0.001), the CTTAD of Ca, lower in T400 vs C0 and CC (P<0.05) and CTTAD of DP-to-DE ratio, lowest in CC and T600 (P<0.001). Dietary tannin significantly modified the CTTAD of FA classes. At weaning, the live weight of CC rabbits was significantly higher than that of the T400 rabbits (974 vs 940 g, P<0.05). The other variables related to growth performance, health status and carcass traits were not affected by the tannin supplementation. The T400 diet fed before weaning seemed to be more effective than the 3 tannin levels administered during fattening period on FA profile change in the LD muscle. T400 diet fed before weaning increased SFA and MUFA (P<0.01) and decreased PUFA (P<0.05), decreasing the n-6/n-3 ratio (P<0.01), however. When tannin-supplemented diets were fed during fattening, only T600 diet showed significantly higher (P<0.05) SFA and MUFA contents compared to CC diet. In conclusion, the dietary inclusion of chestnut hydrolysable tannin doesn’t provides improvements in health status, diet nutritive value, growth performance and carcass traits. Dietary hydrolysable tannin supplementation may play a role on lipid metabolism.