Effects of bentonite on rumen fermentation and duodenal flow of dietary components in sheep fed palm kernel cake by-product

Feeding palm kernel cake (PKC) by-product, which contains relatively high l evels of copper (Cu), may result in hepatic Cu accumulation in ruminants an d in chronic Cu toxicity in sheep. Supplements of bentonite were efficient in alleviating accumulation of Cu in the liver. The objective of the presen t experiment was to determine the effects of supplementation of bentonite ( 2% of dietary dry matter) on rumen fermentation, duodenal flow of amino aci ds (AA), and digestibility in sheep fed PKC-based diets. Rumen and duodenum -cannulated sheep were fed three isonitrogenous PKC-based diets, control (C ), C plus bentonite (CB) and CB plus casein (CBC) as experimental treatment s. The C and CB diets contained 94.5% PKC, and were assigned four sheep eac h, while the CBC diet contained 82% PKC and 2.2% casein, and was assigned t hree sheep. Cellulose was used to bring diets C and CBC to 100% of dry matt er. After 12 days on the diets the sheep were placed in metabolism cages an d feces, duodenal digesta and rumen fluid were sampled on days 14 and 15, 1 6 and 17, and 18 and 19, respectively. On the three diets, rumen pH ranged between 5.9 and 6.0, while ammonia nitrogen (mg/100 mi) ranged between 5.2 on the C diet and 8.5 on the CBC diet. The total volatile fatty acid concen tration (mmol/l) was 41, 51 and 65 on diets C, CB and CBC, respectively. Th e duodenal flow (g/kg organic matter intake) of total AA on the C, CB and C BC diet was 130, 141 and 136, respectively. The total tract digestibility ( %) ranged between 61.9 and 71.3 for organic matter, 65.0 and 72.2 for neutr al detergent fiber, and 73.5 and 76.6 for nitrogen. None of the differences among means of the measured parameters were significant in the present exp eriment (p > 0.05). It was concluded that supplementation of PKC-based diet s with 2% bentonite had no appreciable effect on rumen fermentation, duoden al flow of AA or digestibility in sheep.