1- Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, P. O. Box: 14115-336, Islamic Republic of Iran.
2- Department of Animal Science, Faculty of Agriculture, Bu-Ali Sina University, Hamadan, Islamic Republic of Iran.
Abstract: (10931 Views)
Six rumen fistulated adult sheep were used to assess the effect of tannins (hydrolysable tannin; HTs) in oak leaves (Quercus Libani Oliv.) on ruminal fermentation parameters in a change-over design experiment for 28 days in 3 periods. Polyethylene glycol (PEG) was used 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 and urea) 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 of the measurement periods. In each period, the digestibilities of dry matter (DMD), organic matter (OMD), NDF (NDFD), crude protein (CPD) and ruminal parameters (pH, ammonia, bacteria and protozoa population), and microbial protein synthesis were measured using urinary purine derivatives in sheep. The DMD, OMD, NDFD and CPD were decreased by oak leaves and the addition of PEG improved CPD (P<0.05). The ruminal pH values for all diets were within the normal range. Ruminal ammonia was similar 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 not affected by the diet. Feeding OL diet decreased the microbial N in sheep, whereas addition of PEG improved it. The total protozoa count in sheep offered OL diet declined in 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 fed the control diet (P<0.05), but improved (P< 0.05) with feeding of PEG along with OL. It was concluded that diets containing Q. Libani leaves had lower ruminal fermentability than diet containing alfalfa and that supplementation of PEG in OL diet improved the fermentability.
Received: 2011/09/4 | Accepted: 2011/09/4 | Published: 2011/09/4