Effect of solid-state fermentation with Arxula adeninivorans or Hypocrea jecorina (anamorph Trichoderma reesei) on hygienic quality and in-vitro digestibility of banana peels by mono-gastric animals

This study evaluated the effectiveness of solid-state fermentation with Arxula adeninivorans or Hypocrea jecorina to improve hygienic quality and digestibility of banana peels by mono-gastric animals. Green peels of cooking bananas (Musa AAA-group) were solid-state fermented in ziploc plastic bags for 14 d either non-inoculated or inoculated with A. adeninivorans or H. jecorina. Colonies of aerobic bacteria, lactic acid bacteria, Enterobacteriaceae, yeasts and moulds were enumerated. In-vitro digestibility (total tract and pre-caecal) of dry matter (DM), organic matter (OM) and crude protein (CP) was also determined. Solid-state fermentation significantly improved (P<0.05) in-vitro total tract digestibility (9.9% for DM and 10.1% for OM), and in-vitro pre-caecal digestibility (25.0% for DM, 30.9% for OM and 74.5% for CP); however, no significant effect (P>0.05) due to inoculation was observed. Conversely, inoculation (with A. adeninivorans or H. jecorina) significantly improved (P<0.05) the hygienic quality; with lower (P<0.05) aerobic bacteria, Enterobacteriaceae and mould counts than the non-inoculated treatment. However, H. jecorina triggered a significantly superior (P<0.05) improvement in both hygienic quality and in-vitro pre-caecal digestibility than A. adeninivorans.