Performance, digesta characteristics, nutrient flux, plasma composition, and organ weight in pigs, as affected by dietary cation anion difference andnonstarch polysaccharide

Two dietary cation anion difference (CAD) levels (-100 and 200 mEq/kg) and two dietary nonstarch polysaccharide (NSP) levels (10 and 15%) were used in a 2 x 2 factorial arrangement in two randomized blocks (trials) to evaluat e performance, digesta pH and buffer capacity, apparent digestibility, plas ma composition, and organ weight in pigs. Seven pigs with a mean initial we ight; of 7.5 kg were used in each treatment. Pigs had free access to feed a nd water during the 3-wk experimental period. At the end of the experiment, all pigs were killed approximately 2.5 h after addition of fresh feed. Liv er, kidneys, and small and large intestine were removed and weighed immedia tely. Gastric and small intestinal (divided into two equal parts) digesta w ere collected. Dry matter, pH, buffering capacity, viscosity, acid insolubl e ash, mineral content (Na+, K+, and Cl-), nitrogen, and gross energy conte nt (only in the second part of the small intestine) of the digests were mea sured. An interaction (P < 0.05) between dietary CAD and dietary NSP was: o bserved for feed intake, growth, apparent digestibility of Dill and gross e nergy in the distal small intestine, and chloride in the stomach and duoden o-jejunal part of the small intestine. Increasing dietary NSP content incre ased apparent digestibility of DM and chloride in the stomach and in; creas ed apparent digestibility of DM, chloride, sodium, and potassium in the fir st part of the small intestine. Lowering dietary CAD levels significantly i ncreased apparent digestibility of DM in the first part of the small intest ine and decreased chloride influx in the stomach and the small intestine. N o significant differences were found for pH, buffering capacity, and-viscos ity of digesta, except the buffering capacity in the second part of the sma ll intestine, which was higher (P < 0.05) in the 200 mEq/kg CAD group than in the -100 CAD mEq/kg group. Plasma urea decreased in the low dietary CAD groups and plasma ammonia increased in the high NSP groups. Large intestine weight was significantly less for the -100 mEq/kg CAD groups than for the 200 mEq/kg CAD groups. In conclusion, the effect of CAD on feed intake and growth in pigs depends on dietary NSP levels.