. 2001. Small intestinal morphology and bacterial populations in ileal digesta and feces of newly weaned pigs receiving a high dietary level of zinc oxide. Can. J. Anim. Sci. 81: 511-516. A study was carried out to determine the effect of dietary supplementation of 3000 mg kg -1 zinc oxide (ZnO) on the small intestinal morphology and populations of enterobacteriaceae, lactobacilli and clostridia in ileal digesta and feces of weaned pigs. At 17 d of age, 36 pigs from nine litters were fitted with simple T-cannulae at the distal ileum and after a 2-h post-surgery recovery returned to their sows. At 21 d of age, the pigs were weaned and housed in individual metabolism crates. Pigs were allocated to receive a standard starter diet supplemented with or without 3000 mg kg -1 of ZnO. Ileal digesta and fecal samples were collected immediately before weaning and then on days 2, 4, 7, 9, and 11 after weaning and were used to quantify enterobacteriaceae, lactobacilli and clostridial populations by colony enumeration on selective media. Pigs were euthanized following the final sampling, and 2cm sections of tissue were collected from sites 25, 50 and 75% along the length of the small intestine for determination of mucosal thickness (MT), crypt depth (CD), villous height (VH) and villous width (VW). Zinc oxide supplementation altered the mucosal morphology of the small intestine. Mucosal thickness (P < 0.08) and VH (P < 0.05) were increased at sites 25 and 50% along the length of the small intestine by ZnO supplementation. Overall VW also increased (P < 0.01) with ZnO supplementation. Crypt depth decreased (P < 0.05) at 75% along the length of the small intestine with ZnO supplementation. The ratio of VH to CD was higher (P < 0.05) for ZnO-supplemented than for control-fed pigs at sites 25, 50 and 75% along the length of the small intestine. There was no effect (P > 0.05) of supplementary ZnO on bacterial populations in ileal digesta or feces. The present study indicates that supplementing ZnO in starter diets changes the epithelial morphology of the small intestine, which may affect nutrient digestion and absorption in newly weaned pigs.

Studies were carried out to determine the effect of beta-glucanase supplementation to hulless barley-soybean meal (HB+SBM) or wheat-soybean meal (W+SBM) diets on the digestibilities of GE, CP, beta-glucans, and amino acids. Twelve barrows, average BW 7.3 kg, were fitted with a simple T-cannula at the distal ileum, approximately 5 cm from the ileo-cecal sphincter. After a 7-d recuperation period, six pigs were allotted to each dietary treatment according to a two-period crossover design. Both diets were formulated to contain 20% CP without and with supplementation of .2% beta-glucanase. beta-glucanase refers to a mixture of enzymes with endo- and exo-beta-glucanase and beta-glucosidase activities. Chromic oxide was included as a digestibility marker. The pigs were fed three times daily at 0800, 1600, and 2400 and the daily allowance was offered at a rate of 5% of BW. Each experimental period lasted 9 d. Feces were collected for 48 h on d 6 and 7 and ileal digesta for a total of 24 h on d 8 and 9. beta-glucanase supplementation to the HB+SBM diet increased (P < .05 or P < .01) the ileal digestibilities of GE, CP, beta-glucans, and the majority of the amino acids and the fecal digestibilities of GE, CP, and all amino acids measured; the fecal digestibility of beta-glucans in the HB+SBM diet was not affected by beta-glucanase supplementation. There was no effect (P > .05) of beta-glucanase supplementation to the W+SBM diet on the ileal digestibilities of any criteria measured except for beta-glucans (P < .05). The supplementation of beta-glucanase to the W+SBM diet increased (P < .05) the fecal digestibility of energy but not (P > .05) the other criteria measured.

Experiments were conducted to determine the effect of fumaric acid supplementation and buffering capacity of the diet on ileal and fecal digestibilities of CP, GE, and amino acids in early-weaned pigs. In two experiments, 12 pigs each were weaned at 14 d of age and fitted with a simple T-cannula at the distal ileum between 15 and 17 d of age. In both experiments, the pigs were fed four diets, based on wheat and soybean meal without (control) or with 1, 2, or 3% fumaric acid according to a balanced two-period change-over design. In Exp. 2, the buffering capacity of the diets was increased by supplementation of 3% sodium bicarbonate. The pigs were fed three times daily: equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The inclusion of fumaric acid to the diet with a low buffering capacity increased (P < .05) the ileal digestibilities of CP, GE, and the majority of amino acids. The highest responses were found at an inclusion level of 2% fumaric acid. The improvements in apparent ileal amino acid digestibilities ranged from 4.9 to 12.8 percentage units. Supplementation of fumaric acid to a diet with a high buffering capacity led only to numerical increases in ileal digestibilities of CP, GE, and amino acids. In both studies, fumaric acid supplementation had no effect (P > .05) on the fecal digestibilities of CP, GE, and amino acids, except histidine. A high buffering capacity of the diet decreased the ileal amino acid digestibilities by 1 to 10 percentage units compared with diets with the low buffering capacities. In both experiments, ileal and fecal digestibilities were higher (P < .05) in Period 2 (on d 24 after weaning) than in Period 1 (on d 11 after weaning). A positive correlation (P < .05) between ileal digestibilities and fumaric acid supplementation to the diets with the low buffering capacities was observed in Period 1 (on d 11 after weaning), but not in Period 2 (on d 24 after weaning). No relationship (P > .05) between ileal digestibilities and fumaric acid supplementation to the diets with a high buffering capacity could be established. In conclusion, supplementation of fumaric acid to starter diets during the first 3 to 4 wk after weaning increases the ileal digestibilities of GE, CP, and amino acids.

No abstract

An experiment was carried out to investigate the variability in apparent ileal amino acid (AA) digestibilities in simulated samples of wheat shorts consisting of different proportions of wheat bran (WB), wheat shorts (WS), and wheat flour (WF), hereafter referred to as wheat fractions. The proportions of WS, WB, and WF and the NDF content (DM basis) of the wheat fractions were as follows: A, 70% WS, 30% WB, and 42.3% NDF; B, 85% WS, 15% WB, and 41.8% NDF; C, 100% WS and 41.3% NDF; D, 85% WS, 15% WF, and 35.2% NDF; and E, 70% WS, 30% WF, and 29.5% NDF. Six barrows, average initial BW of 37.2 kg, fitted with a simple T-cannula at the distal ileum, were fed one of six experimental diets according to a 6 x 6 Latin square design. Six diets were formulated to contain 17% CP (as-fed basis). Diets A, B, C, D, and E contained 17.53% soybean meal (SBM), which contributed 50% of the CP in these diets. The wheat fractions contributed the remaining 50% of the CP in these diets. Diet F contained 35.05% SBM, which was the sole source of dietary CP. Chromic oxide was used as the digestibility marker. During the first experimental period, the daily dietary allowance was provided at a rate of 5% (wt/wt) of the average BW. Thereafter, the daily dietary allowance was increased by 100 g at each successive period. Each experimental period comprised 12 d. Following a 7-d adaptation period, feces were collected for 48 h and ileal digesta for a total of 24 h. The apparent ileal digestibilities of AA in the wheat fractions were calculated using the difference method. The digestibilities were usually lowest in the wheat fractions containing WB and highest in those containing no WB. The average of the digestibilities of the indispensable AA was 63.5% for wheat fraction A, which contained 30% WB, and 71.9% for wheat fraction C, which did not contain WB. There were no differences (P > .05) in lysine digestibilities among the wheat fractions, which ranged from 54.7 to 64.1%. Of the indispensable AA, with the exception of arginine, lysine, and methionine, the apparent ileal digestibility values of AA were negatively correlated (P < .05) with the NDF content in the wheat fractions.