Intestinal Fatty Acid Research Articles

The Effect of Lactulose on the Composition of the Intestinal Microbiota and Short-chain Fatty Acid Production in Human Volunteers and a Computercontrolled Model of the Proximal Large Intestine

The Effect of Lactulose on the Composition of the Intestinal Microbiota and Short-chain Fatty Acid Production in Human Volunteers and a Computercontrolled Model of the Proximal Large Intestine

Differences in the fatty acid composition of larvae and metamorphosing sea lampreys, Petromyzon marinus

This study was designed to evaluate biochemical changes in the fatty acid (FA) compositions of selected lipid depot (kidney and liver) and absorption (intestine) organs in larvae and metamorphosing sea lamprey, Petromyzon marinus. Palmitic or stearic acids were generally the predominant saturated fatty acids (SFA) before and during metamorphosis, but the greatest proportion of myristic acid occurred in renal triacylglycerol (TG). Monoenes, dienes, and polyenes consist mainly of 16:1, 18:1, and 20:1, 18:2 and 20:2ω6, and 18:4ω3, respectively. Alterations in these predominant fatty acids occurred during lamprey metamorphosis, but depended on tissue, lipid class, and developmental status. During metamorphosis, kidney TG and phospholipid (PL) classes tended to mobilize SFA and enhance the fatty acid unsaturation, as indicated by increased unsaturated/saturated ratio, unsaturation index (USI), and total mean chain length (MCL). There was a tendency to increase saturation in the fatty acids of liver TG and PL classes and intestine TG, FA and monoacylglycerol (MG) classes, but to increase unsaturation in the fatty acids of liver cholesteryl ester (CE), FA and MG classes and intestine PL and CE classes from larva or stage 3 to stage 7. Increased polyunsaturated fatty acids in kidney TG and PL from larvae to stage 5 transformers and intestine PL and CE from stage 3 to stage 7 transformers may reflect an osmoregulatory pre-adaptation. The presence of branched-chain SFA (BCSFA) and the odd number of fatty acids (ONFA) indicated a significant role of detritivores in the benthic larvae. Decreased abundance of BCSFA, ONFA, and 18:2 dienes occurred in the transformed intestine TG as non-trophic metamorphosis proceeded. These data suggest that sea lamprey metamorphosis may proceed in a habitat, dietary, osmoregulatory, energetic, and developmental pre-adaptation of fatty acid composition from benthic filter-feeding larvae to pelagic parasitic juveniles.

Effects of total enteral and parenteral nutrition on the intestinal flora and fecal shortchain fatty acids

Effects of total enteral and parenteral nutrition on the intestinal flora and fecal shortchain fatty acids

Effects of methotrexate on the intestinal epithelium are influenced by environmental changes

The functions of the intestinal epithelium of patients receiving cytostatic drugs is severely impaired, leading to malabsorption and malnutrition. More insight in mechanisms that mediate mucosal damage and repair is needed for the development of prophylactic regimes. Aim: To further investigate the effects of the cytostatic drug methotrexate (MTX) on functional capacities of intestinal epithelial cells during damage and regeneration by studying epithelial morphology and gene expression. Methods: Rats were subjected to a single or double dose of intraveneously injected MTX ranging from 10 to 60 mg/kg. Rats were kept in cages either alone or grouped (n=4) and sacrificed at 2, 4, 6 or 8 days after the final injection. Jejunal segments were isolated and processed for histochemical analysis. Next to morphology, changes in epithelium-specific differentiation markers were studied at the level of mRNA (in situ hybridization) and protein (immunohistochemistry). Sucraseisomaltase (SI), intestinal (i-) and liver (1-) fatty acid binding protein (FABP) and sodium-glucosetransporter 1 (SGLT1) were used as markers for enterocytes. Mucin (Muc2) and the protease matrilysin were used for goblet cells and Paneth cells, respectively. Results: After a week of adaptation to solitary caging, a single dose of 30, 45 or 60 mg/kg MTX did not lead to any epithelial alterations. However, when two injections of 30 mg/kg MTX were given with a 24 hour interval, 100% mortality occurred at day 6 after the last injection. In rats adapted to group-caging, two-day treatment with 20 mg/kg and 10 mg/kg per day led to villus atrophy that was maximal at day 4 after the last dose and associated with severe cryptloss. In contrast to iand 1-FABP mRNA's, no expression of SI mRNA and SGLT1 mRNA were detected at day 4. At the level of protein, changes in gene expression parallelled the mRNA patterns. Between day 6 and 8, expression 'patterns of all markers returned to normal as the crypt villus architecture restored. Expression patterns of MUC2 and matrilysin mRNA and protein did not show major changes during the period analysed. When rats were caged alone when treatment with MTX started, a single dose of 30 mg/kg affected the epithelium comparable to treatment with 20 mg/kg + 10 mg/kg in rats adapted to group-caging. Conclusions: The observed differences in intestinal epithelial damage between rats adapted to solitary or group-caging versus rats suffering social loss at the moment of MTX treatment, indicate that environmental changes induce a condition of stress leading to increased epithelial sensitivity towards MTX. Still, epithelial damage and mortality also occur in rats kept in a socially known environment using longer period of treatment (2 days). During MTX-induced mucosal damage, enterocyte function is affected with respect to SI and SGLTI expression whereas iand 1-FABP expression is unaltered, suggesting changes in enterocyte metabolism from sugar to fatty acid absorption. Expression of luminal cytoprotective MUC2 and basolateral metalloprotease matrilysin are maintained during MTX-indnced epithelial damage, since these markers remained detectable throughout the study.

Digestion and metabolism of dietary fat in farm animals.

Fat digestion and metabolism differ widely between animal species. In ruminants, dietary fats are hydrogenated in the rumen before intestinal absorption so that absorbed fatty acids (FA) are more saturated than dietary FA. In non-ruminants, intestinal FA digestibility depends on the level of saturation of dietary FA. Fat supplementation of the diet of cows decreases milk protein and has a variable effect on milk fat, depending on the source of dietary lipids. When encapsulated lipids are used, the linoleic acid content of milk is increased, but the organoleptic quality of milk may be altered. Supplementary lipids are incorporated into non-ruminant body fat, whereas de novo lipogenesis is reduced. There is a close relationship between the nature of dietary FA and nonruminant body FA.

Effects of dietary calcium soaps of unsaturated fatty acids on digestion, milk composition and physical properties of butter.

Dairy cows fitted with ruminal, duodenal and ileal cannulas were utilized to investigate the effects of feeding with Ca soaps (CaS) of palm fatty acids (FA) and rapeseed FA. Diets compared were control diet based on maize silage and concentrate, and two diets with 40 g CaS of palm oil FA or rapeseed oil FA/kg diet, replacing part of the concentrates of the control diet. Total digestibilities of dry matter, fibre and fat, and ruminal fermentation were not significantly altered by giving CaS; the extent of ruminal biohydrogenation of total unsaturated C18 FA was significantly reduced by both CaS diets. Apparent intestinal digestibility of FA was not different among diets, although the amount of FA absorbed with the CaS diets was twice that with the control diet. No difference among diets was observed for milk production, or fat and protein contents. Giving CaS diets decreased the proportions of 4:0 to 14:0 FA in milk fat, and increased cis-18:1n-9, compared with control diet. The rapeseed diet lowered the content of 16:0, and increased the contents of 18:0 and trans-18:1n-7. CaS diets did not result in a marked increase of polyunsaturated FA content in milk fat. Butter from cows fed on the CaS diets contained more liquid fat at 6 and 14 degrees C than butter from the cows fed on the control diet. Incorporating CaS, particularly those from rapeseed, in dairy cows' diets increased C18 FA in milk and improved butter spreadability.

The Role of Intestinal Volatile Fatty Acids in the Salmonella Shedding of Pigs

Factors affecting colonization of the intestinal tract by salmonellas were studied in two pig herds. In herd H 18% of the faecal samples taken from live pigs and 30% of the colon content samples collected at slaughter contained salmonellas. In contrast, the 50 faecal samples taken from pigs of herd L were negative and only 2% of the colon contents collected at the yielded salmonellas. An antibacterial effect inhibiting salmonella multiplication was demonstrable in vitro in colon contents from pigs of herd L. No such effect was found to exist in samples taken from pigs of herd H. The antibacterial effect is due to the non-dissociated volatile fatty acid (VFA) molecules present in the colon content. As the degree of VFA dissociation depends on the pH of the environment, at lower pH values (pH 6.1 +/- 0.2) of the colon contents from herd L the ratio of non-dissociated VFA molecules is higher and the resulting antibacterial effect is stronger than in samples from herd H (pH 7.1 +/- 0.3).

Regionally perfused fatty acids augment acid-induced canine pancreatic secretion.

To study interactions between hydrochloric acid and fatty acids on pancreatic secretion, six dogs with chronic gastric, pancreatic, and small intestinal cannulas received various combinations of the following intestinal perfusates: 20, 40, and 80 mM hydrochloric acid, oleate, dodecanoate, or 0.15 M saline. Regional intestinal perfusion (a proximal segment measuring 45 cm from the pancreatic duct versus the remaining small bowel) was utilized to separate the aqueous acid and lipid solutions. Both oleate and dodecanoate augmented the bicarbonate output induced by intraluminal acidification. In other experiments, intraluminal oleate, when combined with exogeneous intravenous secretin (12.5-900 ng . kg-1 . h-1), potentiated the secretin-induced bicarbonate output at low secretin doses. Dodecanoate also increased secretin-induced bicarbonate output. In all of these studies, protein outputs were increased by intestinal fatty acids. It is concluded that intestinal fatty acids can enhanced acid-induced canine pancreatic secretion.

Effect of sucrose feeding upon intestinal and hepatic lipid synthesis

Sucrose induces hypertriglyceridemia and increases intestinal triacylglycerol (TG), cholesterol (C), and very low density lipoprotein (VLDL) secretion in the rat. The effect of feeding a sucrose-enriched diet for 2 to 3 weeks upon rat intestinal and hepatic C, fatty acid (FA), and TG synthesis was measured and compared to animals fed chow and glucose-enriched diets. Sucrose did not alter intestinal lipid composition but increased hepatic weight and TG content. Rates of FA and C synthesis were estimated from the incorporation of 14C-2-acetate and of 3H2O into slices of proximal and distal intestine and of liver. Jejunal, but not ileal, C synthesis was stimulated by sucrose feeding, which resulted in elimination of the jejunoileal gradient for C synthesis found in rats fed control diets. There was no change in intestinal FA synthesis and 14C palmitate incorporation into intestinal TG was reduced. In the liver, no change in hepatic C synthesis was observed, but incorporation of 14C-2-acetate into total fatty acid was increased 3-fold and 3H2O incorporation over 2-fold by sucrose feeding. The incorporation of palmitate into hepatic TG was relatively enhanced and into hepatic phosphoglycerides depressed by sucrose. It is concluded that sucrose feeding stimulates jejunal C synthesis and transport in intestinal lipoproteins but that hepatic C synthesis may be modulated to prevent hypercholesterolemia. Since sucrose feeding docs not increase intestinal lipogenesis, circulating FA may be precursors for VLDL TG secreted in lymph.