Studies were carried out to investigate the effect of dietary amino acid level on apparent ileal amino acid digestibility. Six barrows, average initial BW 35 kg, were fitted with a simple T-cannula at the distal ileum and fed six diets according to a 6 x 6 Latin square design. Six cornstarch-based diets containing six levels of CP from SBM (4, 8, 12, 16, 20, and 24% CP, respectively) were formulated. Chronic oxide was included as a digestibility marker. Each experimental period consisted of 8 d. After a 6-d adaptation period, ileal digesta were collected for 24 h during d 7 and 9 at 2-h intervals. The pigs were fed twice daily, equal amounts, at 0800 and 2000. The dietary allowance was 1,600 g/d during the first period and increased by 100 g each following period. There was a quadratic increase (P < .05) in apparent ileal amino acid digestibility as the dietary CP content was increased from 4 to 24%. Initially, the apparent ileal amino acid digestibilities increased sharply then gradually reached their plateaus, after which there were no further increases and the digestibility values became independent of the dietary amino acid levels. The lower end points of 95% confidence intervals of the plateau ileal digestibility values were defined to be the initial plateau digestibilities. The dietary CP and amino acid contents, corresponding to the initial plateau digestibility values, represent the dietary threshold levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Daily outputs of mucin in ileal digesta were estimated in three barrows fed a protein-free diet while administered either saline (SAI) or a complete amino acid mixture (AAI) intravenously. The water soluble-ethanol precipitable fraction of ileal digesta (crude mucin; CM) was used to estimate the composition of mucin in ileal digesta. This fraction exhibited a carbohydrate composition characteristic of mucin and had a high threonine, serine and proline content (40 mol/100 mol). The proportions of soluble gastric and intestinal mucins, approximately 27 and 73%, respectively, were estimated from the N-acetylglucosamine (GlcNAc)/N-acetylgalactosamine (GalNAc) ratio in CM. The daily outputs of soluble mucin, 2.75 and 3.41 g/day from SAI and AAI pigs (p = 0.13), respectively, were determined from the GalNAc outputs in CM, assuming the above contributions of gastric and intestinal mucins. The estimated soluble mucin outputs accounted for more than 99% of the fucose, galactose, GalNAc and GlcNAc in CM. Total mucin outputs in ileal digesta, 5.32 and 5.65 g/day from SAI and AAI Pigs (p = 0.24), respectively, were determined from the total GalNAc output in digesta, assuming soluble and insoluble mucin had similar compositions. Based on these outputs, mucin represented approximately 30, 7 to 22, 15 and 11% of the endogenous threonine, proline, serine and protein, respectively, in ileal digesta. Approximately 74, 76, 100 and 53% of the fucose, galactose GalNAc and GlcNAc, respectively, in ileal digesta from pigs in this study was attributed to mucin. The results from this study demonstrate the importance of mucin as a source of some endogenous amino acids and carbohydrates.

HLA-B27 transgenic rats develop spontaneous colitis under specific pathogen-free conditions (SPF) but germ-free rats remain disease-free, emphasizing a role for intestinal bacteria in the pathogenesis of chronic intestinal inflammation. Prebiotics are dietary substances that affect the host by stimulating growth and/or activity of potentially health promoting bacteria. The aims of this study were to investigate whether prebiotics can prevent colitis in SPF HLA-B27 rats, and secondly, to explore mechanisms of protection. SPF HLA-B27 transgenic rats received orally the prebiotic combination long-chain inulin and oligofructose (Synergy 1), or not, prior to the development of clinically detectable colitis. After seven weeks, cecal and colonic tissues were collected for gross cecal scores (GCS), histologic inflammatory scores (scale 0-4), and mucosal cytokine measurement. Cecal and colonic contents were collected for analysis of the gut microbiota by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and fluorescent in-situ hybridization (FISH), and analysis of short-chain fatty acid composition. Prebiotic treatment significantly decreased GCS and inflammatory histologic scores in the cecum and colon. Prebiotic treatment also decreased cecal IL-1beta, but increased cecal TGF-beta concentrations. Inulin/oligofructose altered the cecal and colonic PCR-DGGE profiles, and FISH analysis showed significant increases in cecal Lactobacillus and Bifidobacterium populations after prebiotic treatment compared with water-treated rats. In conclusion, the prebiotic combination Synergy 1 reduced colitis in HLA-B27 transgenic rats, which effect was associated with alterations to the gut microbiota, decreased tissue proinflammatory cytokines and increased immunomodulatory molecules. These results show promise for prebiotics as primary or adjuvant maintenance therapy for chronic inflammatory bowel diseases.

Current information on the effect of diet on the secretion of mucus and the recovery of mucin in ileal digesta is summarized. A general description of mucus structure and its degradation in the small and large intestine is provided. As the protective lining of the entire gastrointestinal tract, mucus gels are exposed to all chemical and physical forces of digestion. Most important among these is the proteolytic breakdown of mucus gels into component mucin subunits and their subsequent release into the intestinal lumen. Erosion of mucus gels is countered by synthesis and secretion from the underlying epithelium. Diets can influence this process, both indirectly by their effects on digestive processes most importantly with respect to the amount and distribution of proteolytic enzymes in the intestinal lumen, and directly by the physical forces which they exert on the gastrointestinal mucosa. Adaptive changes in goblet cell activity have been noted in response to different diets. Once in the intestinal lumen, little further degradation of mucus occurs prior to the large intestine. Once in the large intestine mucin is fermented by resident microbial populations. The recovery of undegraded mucin in ileal digesta has important implications for nutritional studies: firstly because it may represent a considerable loss of endogenous amino acids and carbohydrates and secondly because it may provide insight into the effects of diets on the digestive tract itself.

. 2001. Effects of feeding different levels of conjugated linoleic acid and total oil to pigs on live animal performance and carcass composition. Can. J. Anim. Sci. 81: 505-510. The effects of feeding different dietary levels of conjugated linoleic acid (CLA) and total oil (TO) were evaluated using 216 barrows fed from 36 to 115 kg body weight. A 3 × 2 factorial design was used with three levels of dietary CLA (0, 0.25, and 0.5%), two levels of dietary TO (2 and 5% made up with canola oil) and 12 pens of three barrows fed per diet. Pigs on all diets gained weight at the same rate from 0 to 4 wk (36 to 61 kg) and from 4 wk to slaughter (61 kg to 115 kg) (P > 0.05). Pigs fed 5% versus 2% TO had 6.6% lower feed intake from 0 to 4 wk (P = 0.02) and 5.9% lower feed intake from 4 wk to slaughter (P < 0.003), while feeding CLA had no effect on feed intake (P = 0.70). A CLA by TO interaction for feed intake was not found for 0 to 4 wk but from 4 wk to slaughter a tendency for an interaction (P = 0.06) was found indicating 0.25% CLA may depress feed intake at 2% TO while stimulating intake at 5% TO. Increasing TO and CLA increased the lean content in commercial cuts by 1.6% (P = 0.06) and 2.7% (P = 0.008), respectively. A CLA by TO interaction (P = 0.012), however, indicated CLA was less effective at increasing lean when added to 5% TO diets than to 2% TO diets, with pigs fed the 0% CLA/2% TO diet yielding 5% less lean than pigs fed any of the other diets (P < 0.05). Interestingly, a main effect for TO was not found for subcutaneous fat (SCF), but adding CLA reduced SCF (6.6%; P = 0.002). Again, a CLA by TO interaction (P = 0.008) indicated adding CLA was less effective at reducing SCF in 5% TO than 2% TO diets, with pigs fed the 0% CLA/2% TO diet having 9.7% more SCF than pigs fed any of the other diets (P < 0.05). The difference in effectiveness of CLA at different TO levels might be due to dilution of CLA by canola oil fatty acids and/or canola oil having fat to lean repartitioning effects of its own. A comparison of fats and oils with differing chain lengths and degrees of saturation would, therefore, be of interest to further define their potential differential effects on growth and metabolism. . La prise alimentaire des truies qui recevaient 5 % de HT plutôt que 2 % a diminué de 6,6 % lors des quatre premières semaines (P = 0,02) et de 5,9 % de 4 semaines à l'abattage (P < 0,003), alors que l'ingestion d'ALC n'a eu aucun effet sur ce paramètre (P = 0,70). L'ALC n'interagit pas avec la HT au niveau de la prise alimentaire de 0 à 4 semaines, mais de 4 semaines à l'abattage, on note une tendance en ce sens (P = 0,06) indiquant qu'à partir de 0,25 %, l'ALC pourrait réduire la prise alimentaire dans les rations contenant 2 % de HT et l'augmenter quand la ration en renferme 5 %. Quand on augmente la proportion d'ALC et de HT, la teneur en viande maigre des morceaux commerciaux augmente de 1,6 % (P = 0,06) et de 2,7 % (P = 0,008), respectivement. Une interaction entre l'ALC et la HT (P = 0,012) révèle néanmoins que l'ALC ...