Effect of oak (quercus libani oliv.) leave tannin on ruminal fermentation of sheep.

Six rumen fistulated adult sheep were used to assess the effect of tannins (hydrolysabletannin; HTs) in oak leaves (Quercus Libani Oliv.) on ruminal fermentation parameters ina change-over design experiment for 28 days in 3 periods. Polyethylene glycol (PEG) wasused to deactivate the tannins. The three dietary treatments were control (alfalfa hay,barley grain, wheat bran, wheat straw); OL (oak leave, barley grain, wheat bran andurea) and OL+ 80 g PEG. Animals were held in individual pens and metabolism cages.They were adapted to experimental conditions for 21 days before the commencement ofthe measurement periods. In each period, the digestibilities of dry matter (DMD), organicmatter (OMD), NDF (NDFD), crude protein (CPD) and ruminal parameters (pH,ammonia, bacteria and protozoa population), and microbial protein synthesis weremeasured using urinary purine derivatives in sheep. The DMD, OMD, NDFD and CPDwere decreased by oak leaves and the addition of PEG improved CPD (P<0.05). Theruminal pH values for all diets were within the normal range. Ruminal ammonia wassimilar among the treatments (p>0.05). Hydrolysable tannins in OL diets decreased(P<0.05) urinary allantoin in comparison to the control diet. Addition of PEG increased(P<0.05) allantoin. The uric acid, xanthine and hypoxanthine excretion in urine were notaffected by the diet. Feeding OL diet decreased the microbial N in sheep, whereasaddition of PEG improved it. The total protozoa count in sheep offered OL diet declinedin comparison to those fed the control diet; however, addition of PEG had no effect on it.Sheep fed OL diet had significantly less cellulolytic and proteolytic bacteria than those fedthe control diet (P<0.05), but improved (P< 0.05) with feeding of PEG along with OL. Itwas concluded that diets containing Q. Libani leaves had lower ruminal fermentabilitythan diet containing alfalfa and that supplementation of PEG in OL diet improved thefermentability.Keywords: Microflora, Oak leave, Polyethylene glycol, Rumen, Sheep, Tannin.