Changes In Digestive Function Research Articles

STUDY ON SILENCER ACOUSTIC EFFICIENCY IN GAS-AIR FLOW DUCT BENDS

The study examines a topical problem of increased noise nuisance originating from energy facilities at thermal mechanical equipment tight integration. Noise negatively affects residents of large cities and could contribute to development of chronic diseases characterized by such symptoms as reduced hearing sensitivity, changes in digestive function, cardiovascular insufficiency and neuroendocrine disorder. At the heat supply energy facilities, main sources of noise and vibration include pumping equipment, boiler burners and gas-air flow ducts, as well as ventilation systems. This paper considers the problem of noise reduction in the boiler gas-air flow ducts. Original design of a dissipative silencer in the form of a bent is proposed, which use is relevant, if extended straight sections of gas-air flow ducts are missing. Results of the developed silencer full-scale bench tests are presented. According to test results, the silencer acoustic efficiency constituted 18 dBA.

Assessing mechanisms of toxicant response in the amphipod Melita plumulosa through transcriptomic profiling

This study describes the function of transcripts with altered abundance in the epibenthic amphipod, Melita plumulosa, following whole-sediment exposure to a series of common environmental contaminants. M. plumulosa were exposed for 48h to sediments spiked and equilibrated with the following contaminants at concentrations predicted to cause sublethal effects to reproduction: porewater ammonia 30mgL−1; bifenthrin at 100μgkg−1; fipronil at 50μgkg−1; 0.6% diesel; 0.3% crude oil; 250mgCukg−1; 400mgNikg−1; and 400mgZnkg−1. RNA was extracted and hybridized against a custom Agilent microarray developed for this species. Although the microarray represented a partial transcriptome and not all features on the array could be annotated, unique transcriptomic profiles were generated for each of the contaminant exposures. Hierarchical clustering grouped the expression profiles together by contaminant class, with copper and zinc, the petroleum products and nickel, and the pesticides each forming a distinct cluster. Many of the transcriptional changes observed were consistent with patterns previously described in other crustaceans. The changes in the transcriptome demonstrated that contaminant exposure caused changes in digestive function, growth and moulting, and the cytoskeleton following metal exposure, whereas exposure to petroleum products caused changes in carbohydrate metabolism, xenobiotic metabolism and hormone cycling. Functional analysis of these gene expression profiles can provide a better understanding of modes of toxic action and permits the prediction of mixture effects within contaminated ecosystems.

Feeding behaviour and digestive physiology in larval fish: current knowledge, and gaps and bottlenecks in research

AbstractFood uptake follows rules defined by feeding behaviour that determines the kind and quantity of food ingested by fish larvae as well as how live prey and food particles are detected, captured and ingested. Feeding success depends on the progressive development of anatomical characteristics and physiological functions and on the availability of suitable food items throughout larval development. The fish larval stages present eco‐morpho‐physiological features very different from adults and differ from one species to another. The organoleptic properties, dimensions, detectability, movements characteristics and buoyancy of food items are all crucial features that should be considered, but is often ignored, in feeding regimes. Ontogenetic changes in digestive function lead to limitations in the ability to process certain feedstuffs. There is still a lack of knowledge about the digestion and absorption of various nutrients and about the ontogeny of basic physiological mechanisms in fish larvae, including how they are affected by genetic, dietary and environmental factors. The neural and hormonal regulation of the digestive process and of appetite is critical for optimizing digestion. These processes are still poorly described in fish larvae and attempts to develop optimal feeding regimes are often still on a ‘trial and error’ basis. A holistic understanding of feeding ecology and digestive functions is important for designing diets for fish larvae and the adaptation of rearing conditions to meet requirements for the best presentation of prey and microdiets, and their optimal ingestion, digestion and absorption. More research that targets gaps in our knowledge should advance larval rearing.

Up-regulation of intestinal type 1 taste receptor 3 and sodium glucose luminal transporter-1 expression and increased sucrose intake in mice lacking gut microbiota

The chemosensory components shared by both lingual and intestinal epithelium play a critical role in food consumption and the regulation of intestinal functions. In addition to nutrient signals, other luminal contents, including micro-organisms, are important in signalling across the gastrointestinal mucosa and initiating changes in digestive functions. A potential role of gut microbiota in influencing food intake, energy homeostasis and weight gain has been suggested. However, whether gut microbiota modulates the expression of nutrient-responsive receptors and transporters, leading to altered food consumption, is unknown. Thus, we examined the preference for nutritive (sucrose) and non-nutritive (saccharin) sweet solutions in germ-free (GF, C57BL/6J) mice compared with conventional (CV, C57BL/6J) control mice using a two-bottle preference test. Then, we quantified mRNA and protein expression of the sweet signalling protein type 1 taste receptor 3 (T1R3) and α-gustducin and Na glucose luminal transporter-1 (SGLT-1) of the intestinal epithelium of both CV and GF mice. Additionally, we measured gene expression of T1R2, T1R3 and α-gustducin in the lingual epithelium. We found that, while the preference for sucrose was similar between the groups, GF mice consumed more of the high concentration (8%) of sucrose solution than CV mice. There was no difference in either the intake of or the preference for saccharin. GF mice expressed significantly more T1R3 and SGLT-1 mRNA and protein in the intestinal epithelium compared with CV mice; however, lingual taste receptor mRNA expression was similar between the groups. We conclude that the absence of intestinal microbiota alters the expression of sweet taste receptors and GLUT in the proximal small intestine, which is associated with increased consumption of nutritive sweet solutions.

What is the effect of inflammation on intestinal function?

Chronic inflammatory bowel disease (IBD—Crohn’s disease [CD] and ulcerative colitis [UC]) are conditions characterized by widespread changes in bowel physiology, including abnormal secretion, motor dysfunction, and increased sensory perception. These changes contribute significantly to the generation of patient’s symptoms, such as abdominal pain and diarrhea.1,2 Attention has been recently paid to the impact of intestinal inflammation on the enteric nervous system (ENS), the major control mechanism of digestive functions. Nonetheless, it must be also acknowledged that changes in digestive functions in this context may be the consequence of the direct impact of inflammatory mediators on the target cells (e.g., epithelial and smooth muscle cells). Significant progress in our understanding of the mechanisms of altered bowel function in IBD has been achieved through the identification of the molecular basis of the interplay between bioactive substances released by inflammatory cells (e.g., cytokines, prostanoids, free radicals, etc.) and neural, muscular, epithelial, and endocrine cells controlling gastrointestinal function. Recent evidence shows that mild inflammation and subtle ENS abnormalities, including changes in nerve electrophysiology, chemical coding, and receptors expression (i.e., which have been referred to as neuronal plasticity) underlie substantial bowel dysfunction. These neuroplastic changes may play a role in bowel dysfunction detected at gastrointestinal sites not frankly involved by the inflammatory process or in sympathetic and parasympathetic branches of the autonomic nervous system residing outside of the gut wall.3 Based on these data, neuroplastic changes have been proposed to explain symptom perception also in patients with milder disease or during periods of remission of IBD. Animal models have provided important mechanistic insights into the pathophysiology of bowel dysfunction during intestinal inflammation. However, it must be noted that many of the morphological changes occurring at the level of the ENS and muscle described in IBD tissues cannot be reproduced in these experimental models. This is probably due to the fact that the chronic effect of inflammation present in human IBD determines changes that are difficult to be reproduced in the short course of inflammation in animals. In this brief review only general concepts and relevant examples of the impact of intestinal inflammation on the ENS and related functions will be discussed.

Aspects of gastrointestinal motility in relation to the development of digestive function in neonates

Gastrointestinal motility is responsible for mixing and transport of digesta and elimination of undigested residues. The basis for the motility is the electrical activity of the gastrointestinal smooth muscle, which has a recurring pattern. In the small intestine of mature animals, this pattern is associated with periodic fluctuations of mesenteric blood flow, and gastric, pancreatic and biliary secretion, and with intestinal absorption. In general, feeding disrupts the cyclic pattern in the stomach and small intestine, replacing it with a continuous post-feeding pattern, and the duration of the post-feeding pattern is dependent on animal species, composition of the diet and feeding regime. The perinatal and weaning periods manifest drastic changes in digestive function and, thus, in gastrointestinal motility. Due to difficulties in performing studies in perinatal and neonatal animals, only few data on the development of gastrointestinal motility, and its synchronisation with other digestive functions, are available. Whereas some studies in the literature indicate that the development of gastrointestinal motility follows the maturation of the regulatory mechanisms, recent data also suggest that changes in gastrointestinal motility around birth and weaning reflect changes in nutrient supply. This paper deals with some aspects of gastrointestinal motility, primarily in the gastric antrum and small intestine, of neonatal animals. Certainly, changes in gastrointestinal motility in early life could be of paramount importance for proper digestive function and this research area requires further attention.

Development of intestinal brush border aminopeptidase in the larval japanese flounder Paralichthys olivaceus

In the present study, immunohistochemical methods have been used to localize aminopeptidase on the intestinal brush border of Japanese flounder Paralichthys olivaceus with a view to tracing the changes in digestive function of the intestinal brush border that occur during the larval stage. Aminopeptidase was purified from the intestinal brush border of adult red seabream Pagrus major, and an anti-aminopeptidase antibody (anti-rAmp) prepared. Because the anti-rAmp recognized the aminopeptidases of four species of fish but not those of zooplankton, it was applied to flounder larvae. The intestinal epithelial cells of the flounder were found to have already begun to synthesize aminopeptidase before hatching and to possess nearly complete capability at 2 day-post-hatching, i.e., 1 day prior to exogenous feeding.

Treatment of lower urinary tract dysfunction in patients with multiple sclerosis. Committee of the European Study Group of SUDIMS (Sexual and Urological Disorders in Multiple Sclerosis)

Bladder symptoms in patients with multiple sclerosis (MS) are common and usually arise as a result of spinal lesions which interrupt the neural pathways connecting the pontine micturition centre to the sacral spinal cord. Thus these symptoms are particularly likely to occur in those with lower limb neurological deficits. Fortunately bladder dysfunction in MS is rarely associated with serious upper tract disease so that the problem is usually one of symptomatic management. Lower urinary tract symptoms may be both "irritative" or "obstructive" in nature and can be explained in terms of underlying detrusor hyperreflexia and incomplete bladder emptying. Treatment is aimed at minimising both these effects. Oral anticholinergic medication can be effective in reducing detrusor hyperreflexia and intermittent catheterisation is used to reduce abnormally high post micturition residual volumes. With this simple treatment, often used in combination, many less severely affected patients with MS can gain considerable improvement in controlling urinary continence.

Digestive development of the early-weaned pig

Gastric intubation was adopted to examine the effect of continuous nutrient supply on digestive development of the pig during the immediate post-weaning period. The 14 d-weaned animals were slaughtered at 3, 5 and 7 d post-weaning (3W, 5W and 7W respectively) and the suckled animals were slaughtered at 14 and 22 d of age (14SR and 22SR respectively). The weight of the pancreas (g/kg bodyweight) was significantly greater (P less than 0.05) in the 5W and 7W groups, as was the weight of large intestine (g/kg) in all weaned groups (P less than 0.01) compared with sow-reared pigs. The stomach weight (g/kg) tended to be greater in the weaned groups. Weaning, in conjunction with a continuous nutrient supply, did not significantly alter the time-related changes in the weight of the small intestine (SI) or the SI mucosa, although both variables tended to be lowest in the 3W group. However, there was a 20% reduction in the protein content of the mucosa within the first 3 d post-weaning (P less than 0.01) which persisted during the 7 d experimental period. Lactase, (beta-galactosidase; EC 3.2.1.23) activity (mumol/g protein and mol/d) of the 7W group was reduced to approximately 40% of the 22SR value. Hence, continuous nutrient supply may have delayed, but did not prevent, the loss of lactase activity at weaning. The activity of sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) was significantly higher in 22SR compared with 14SR animals. Sucrase activity in weaned pigs was intermediate to the values for sow-reared pigs whereas maltase (alpha-glucosidase; EC 3.2.1.20) and glucoamylase (glucan 1,4-alpha-glucosidase; EC 3.2.1.3) were significantly increased in relation to their sow-reared counterparts. Continuous nutrient supply did not prevent the reduction in villous height and the crypt hypertrophy associated with weaning. The results of the present study suggest that there may be some degree of interaction between nutrient intake and gut development during the immediate post-weaning period but that there is also a component of the adaptive response which is independent of nutrient intake. They confirm the rapid substrate induction of the brush-border glucoamylases and indicate the importance of considering total as well as specific enzyme activity for satisfactory interpretation of changes in digestive function.

Effect of age, abomasal cannulation and rumen catheterization on intake and site of digestion by early-weaned lambs

SUMMARYThe voluntary food intake, in vivo digestibility and site of nutrient digestion was measured in 12 Polled Dorset ram lambs, from 6 to 24 weeks of age, offered clover hay. Lambs were weaned at 6 weeks of age. Six were fitted with a permanent T-shaped cannula in the abomasum and a temporary rumen catheter during the periods of digesta flow measurement.Surgical modification of lambs did not influence intake (g/kg live weight (W) per day), in vivo digestibility or marker retention time in the rumen. However, intact lambs grew significantly faster than cannulated lambs (139 v. 109g/day, P < 0·05) apparently because of an overall higher cumulative intake over the whole experimental period rather than any change in efficiency of use of nutrients or maintenance requirement.Relative to live weight, intake increased rapidly until c. 10 weeks of age and remained relatively constant at c. 37 g DM/kg W per day for the remainder of the experiment. Age had no effect on in vivo digestibility of organic matter (OM) or neutral detergent fibre (NDF) (average 0·69).The proportion of digestible organic matter apparently digested in the rumen (DOMADR) decreased from 0·63 to 0·47 between 8 and 24 weeks of age whilst intake between these measurement periods increased. Nonammonia N (NAN) flow past the abomasum was similar at all ages in relation to digestible organic matter intake (55·1 g NAN/kg DOMI) but was higher at 16 and 24 weeks of age than at 8 and 12 weeks of age, respectively, in relation to organic matter apparently digested in the rumen (OMADR) (116 and 85 g NAN/kg OMADR, respectively, P < 0·05).Fractional outflow rate of digesta markers from the rumen, when estimated from abomasal digesta, was significantly higher than when estimated from faeces (103Ru-p 0·121 v. 0·09; 51Cr-EDTA 0·169 v. 0·111/h; P > 0·05).It was concluded that cannulation did not affect intake and digestion characteristics in these young lambs. The changes in the site of nutrient digestion as the animals aged may have been due to agerelated changes in digestive function but appeared to be associated with the increase in intake that occurred between measurement periods of the cannulated lambs.

Ostertagia ostertagi infection in the calf: effects of a trickle challenge on the hormonal control of digestive and metabolic function

Metabolic effects of a trickle challenge with the equivalent of 10,000 infective Ostertagia ostertagi larvae per day were investigated in 12 calves allocated to infected, pair-fed control or ad libitum-fed control groups. Changes in hormone levels reflecting abomasal, pituitary and pancreatic function were monitored using radioimmunoassay techniques previously validated for use in cattle. A range of metabolic profile parameters and blood metabolites was also measured. Feed intake of the infected calves began to decline as blood gastrin and pepsinogen levels reached a peak. The depression in appetite recorded in this group was responsible for significant increases in plasma urea and non-esterified fatty acid levels and associated with an increase in growth hormone/insulin ratio. No significant difference in glucagon levels was recorded between groups. A decline in blood albumin values was also shown in the infected group and associated with a drop in nitrogen digestibility. A significant depression in circulating calcium levels was related to either the hypoalbuminaemia or impaired mineral absorption in the intestine. A decrease in plasma cholesterol values in the infected group was associated with changes in digestive function.

Normal pancreatic and intestinal enzymes in hypophagic growth-retarded rats that received dorsomedial hypothalamic lesions shortly after weaning

Male weanling Sprague-Dawley rats received bilateral electrolytic lesions in the dorsomedial hypothalamic nuclei (DMNL rats). Sham-operated rats served as controls. After being fed lab chow for two postoperative weeks, the animals were divided into four groups. One group of DMNL rats and controls received a high-caloric diet (high-fat diet, chocolate chip cookies, 32% sucrose solution, potato chips and marshmallows), whereas another group of DMNL rats and controls continued to receive lab chow. The experiment was terminated on the 185th postoperative day. In accordance with previous findings, DMNL rats, irrespective of diet, were lighter and shorter than controls. In addition, DMNL rats fed junk food were lighter than DMNL rats fed lab chow, and junk-fed controls weighed as much as chow-fed controls. Both DMNL rats and controls fed junk food were also shorter and showed higher carcass fat than their chow-fed counterparts. Also, DMNL rats fed junk food had less carcass fat than junk-fed sham-operated controls, whereas in accordance with previous findings, there was no difference between chow-fed DMNL rats and chow-fed sham-operated controls. Irrespective of diet, DMNL rats ate less calories than their respective sham-operated controls. Both absolute and percent pancreas weight and protein pancreas weight and protein/pancreas were unaffected in DMNL rate but were reduced in both junk-fed groups in comparison with their chow-fed counterparts. Both concentrations and contents of pancreatic trypsinogen, amylase and lipase were unaffected in DMNL rats but total activities of all three enzymes were dramatically reduced in the junk-fed compared with the chow-fed DMNL rats. Total activities of trypsinogen and amylase but not lipase were also reduced. Duodenal mucosal weight, total protein and specific activities of enterokinase, leucine amino peptidase and maltase were uninfluenced by lesions and diet alike. In the jejunum, specific activity of enterokinase was dramatically reduced in junk-fed versus chow-fed DMNL rats; the same obtained for junk-fed vs. chow-fed sham-operated control groups. Jejunal lactase, sucrose and maltase were not affected by DMN lesions but both DMNL rats and sham-operated controls fed junk foods showed lower specific activities than their chow-fed counterparts. The data indicate that production of DMN lesions in weanling rats, although followed by dramatic alterations in ponderal and linear growth and food intake, causes little, if any, changes in a number of pancreatic and small intestinal parameters, including enzymes. The only significant changes are those related to diet effects. These findings suggest that the DMNL rat responds to dietary factors like its sham-operated control and suggest that changes in digestive function cannot be invoked as possible causes of growth retardation and food intake in the weanling DMNL rat.