Effect of dietary fibre and condensed tannins concentration from various fibrous feedstuffs on in vitro gas production kinetics with rabbit faecal inoculum

The aim of the study was to compare nutrients, condensed tannins, fibre and in vitro fermentation parameters from different fibrous feedstuffs, both common (sugar beet pulp, wheat bran, lucerne meal) and uncommon (tomato pomace, maize bran, rice bran, lentil bran and pomegranate peel) in rabbit feeds with the in vitro gas production technique using rabbit faeces inoculum. The total dietary fibre and insoluble dietary fibre concentration were the lowest (28.9 and 23.7%) for rice bran and the highest (70.2 and 63.1%) for sugar beet pulp. The highest digestible fibre fraction was in sugar beet pulp (44.5%). The highest total condensed tannin, bound condensed tannin and extractable condensed tannin levels were determined in lentil bran. The in vitro gas production from insoluble fraction (b(gas); 111 and 100 ml . 0.5 g(-1) DM, respectively) and potential gas production values [(a+b)(gas); 105.5 and 94.7 ml . 0.5 g(-1) DM, respectively] were the highest in tomato pomace and sugar beet pulp. The b(gas) and (a+b)(gas) values of maize bran were higher by about 50% than those of wheat and rice bran (P < 0.001). The b(gas) and (a+b)(gas) values of pomegranate peel were approximately 4 times higher than those of lentil bran (P < 0.001). These results suggested that considering in vitro gas production tomato pomace, maize bran and rice bran could be further studied for use as alternative dietary fibrous feedstuffs for rabbit. It can be suggested that pomegranate pomace and lentil bran could be used as alternative dietary fibrous feedstuffs for the growing rabbit due to their high fibre content and low fermentation capacity