In vitro fermentation of commonly fed herbivorous feedstuffs using African elephant (Loxodonta africana) faecal inoculum

Abstract

Gastrointestinal issues and elevated body condition scores are concerns for human-managed African elephants Loxodonta africana. Thus, research to formulate appropriate feeding programmes is paramount. Fermentability of seven commonly fed types of forage were studied in-vitro using faeces from human-managed African elephants as an inoculum source. Air-dried plant samples (0.5 g) from various harvest seasons [timothy hay (n=4 seasons), N&S grass (n=2), alfalfa hay (n=3), tulip poplar (n=2), thorny elaeagnus (n=3), sweet gum (n=3) and willow oak (n=3)] were incubated with buffered faecal inoculum (n=4 elephants). Gas production was measured over 72 hr and concentration of short-chain fatty acids (SCFA) and ammonia at 72 hr. The fermentation parameters varied widely among plant species (P<0.001) with grass and legume species being more fermentable than browse species. Gas production ranged from 22 ml/g organic matter (OM) for willow oak to 140 ml/g OM for alfalfa hay and SCFA from 1.38 (willow oak) to 5.43 (alfalfa hay) mmol/g OM. Within forage, differences in fermentability (P<0.05) were found between harvest seasons for timothy hay, N&S grass and alfalfa hay (for total SCFA 7 to 23% deviation from the average) but this effect was limited or absent for the browse species. Total SCFA correlated with dietary fibre (R2=0.477, P<0.001), lignin (R2=0.432, P=0.002) and with non-starch polysaccharide + lignin (R2=0.637, P<0.001). It is recommended to consider fermentative capacity of evaluated forage species and also harvest season for the grass and legume species in African elephant feeding management programmes to assure elephant body condition and nutritional health.