Effect of oak (Quercus persica) acorn level on apparent digestibility, ruminal fermentation, nitrogen balance and urinary purine derivatives in pregnant goats.

Abstract

The aim of this experiment was to investigate the effect of dietary oak (Quercus persica) acorn (OA) level on dry matter intake (DMI), apparent nutrient digestibility, nitrogen (N) utilization, ruminal fermentation, protozoa population and urinary purine derivatives (PD) during the last 60days of goat pregnancy. Twenty-four multiparous pregnant goats (41.7±2.3kg BW) were assigned to one of three experimental diets consisted of control diet (C, without OA) and diets containing 20 (OA20 ) or 40g/100g of OA (OA40 ) on a DM basis in a completely randomized block design. Goats fed OA40 had lower DMI (p<.01), DM (p<.01), OM (p<.01) and NDF (p<.05) digestibility, ruminal NH3 -N concentration (p<.01), N intake (p<.01) and N retention (p<.01). Crude protein digestibility and ruminal acetate and total volatile fatty acid (VFA) concentration were lower in animals fed OA-contained diets (p<.01), whereas ruminal propionate concentration was higher in goats fed the C diet (p<.01). Animals fed OA40 had higher faecal N excretion and lower urinary N excretion (p<.01). Urinary PD was lower in goats fed diets containing OA in relation to those fed the C diet (p<.01). Total protozoa population decreased linearly with increasing OA level in the diet (p<.05). These results suggest that feeding OA, especially high level, has negative impacts on DMI, nutrient digestibility, VFA concentration, N retention and urinary PD excretion that may have adverse effects on metabolism and performance of pregnant goats.