Gut Transit Time Research Articles

Evaluation of regional and whole gut motility using the wireless motility capsule: relevance in clinical practice

The wireless motility capsule (WMC) is an ambulatory noninvasive and nonradioactive diagnostic sensor that continuously samples intraluminal pH, temperature, and pressure as it moves through the gastrointestinal (GI) tract. This review summarizes the data obtained in clinical trials with the WMC and discusses its role in clinical practice. The United States Food and Drug Administration has approved the SmartPill GI monitoring system for the evaluation of gastric emptying time in patients with suspected gastroparesis, the evaluation of colonic transit time in patients with suspected chronic constipation, and for the characterization of pressure profiles from the antrum and duodenum. Clinical studies have shown that WMC-measured GI transit times can distinguish patients with motility abnormalities similarly to conventional testing. However, the WMC offers the advantage of providing a full GI-tract profile, enabling the detection of multiregional GI transit abnormalities in patients with suspected upper or lower GI dysmotility. The WMC also characterizes pressure profiles of the GI tract and impaired pressure profile limits are reported for the antrum and duodenum. In comparison with manometry, interpretations of pressure measurements obtained by the WMC are limited by an inability to detect a peristaltic pressure wave front, and further investigation is required to develop clinical applications. Clinical studies with the WMC indicated that it should be considered for the evaluation of regional and whole gut transit time in patients with suspected upper or lower dysmotility, particularly if there are concerns about multiregional dysmotility.

Effects of adlay, buckwheat, and barley on transit time and the antioxidative system in obesity induced rats

In the present study, we examined whether four grains including adlay (AD), buckwheat (BW), glutinous barley (GB), and white rice (WR) affect the duration of food residence in the gastrointestinal tract and hepatic enzyme activities in rats fed different combinations of the grains. The rats were raised for 4 weeks on a high fat diet based on the American Institute of Nutrition-93 (AIN-93G) diets containing 1% cholesterol and 20% dietary lipids. Forty male rats were divided into four groups and raised for 4 weeks with a diet containing one of the grains. Corresponding to the dietary fiber contents of the experimental grains, gut transit time was shortest in the rats fed GB and increased in the order of BW, AD, and WR. In addition, the accumulated shortest transit time occurred in the GB group. Gut transit time affected weight gain and major organ weight, as it was closely related to the absorption of nutrients. The level of thiobarbituric acid reactive substance (TBARS) in liver was higher in rats fed WR, AD, BW, and GB, indicating that the other grains decreased oxidative stress in vivo more than WR. Glutathione, glutathione peroxidase, and glutathione S-transferase levels in the AD, BW, and GB groups were significantly higher than those in the WR group. In conclusion, reduced colonic transit time has been implicated in reducing the incidence of colon cancer, as evidenced by populations consuming diets rich in fiber. Whole grains such as AD, BW, and GB may contribute to a significant supply of antioxidants to prevent oxidative stress if they are consumed in large amounts.

Evaluation of Salmonella Movement Through the Gut of the Lesser Mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

The lesser mealworm, Alphitobius diaperinus is an important poultry pest prevalent during production that is capable of vectoring pathogens. This study was undertaken to determine the gut transit time of Salmonella for biosecurity risk analysis of pathogen dispersal into the environment. Adult and larval A. diaperinus were exposed to two concentrations of a fluorescently labeled Salmonella enterica for 15, 30, and 60 min time periods then externally disinfected to evaluate internal transfer of Salmonella. The insects were monitored every 30 min over 4 h and evacuated frass (feces) processed for the marker Salmonella. The minimum time monitored was 45 min (15 exposure+30 min time point), and the maximum was 5 h (60 exposure+4 h time point). Adults treated with 10(6) or 10(8) colony-forming units (cfu)/mL, which produced Salmonella positive frass within the 5 h experimental time, displayed a mean gut transit time of 144.4 min (range 90-270 min) and 186.3 min (range 120-300 min), respectively. Larvae treated with 10(6) or 10(8) cfu/mL displayed a mean gut transit time of 172.5 min (range 120-300 min) and 131.7 min (range 60-300 min), respectively. Understanding the sources and contribution of reservoir populations of pathogens in poultry production operations is important for development of biosecurity measures to mitigate their transfer. A. diaperinus are prevalent in production operations and difficult to suppress. Management standards accept the reutilization of litter in which insects survive between flock rotations. Removing litter and spreading it onto nearby fields results in the inadvertent dispersal of beetles. Few studies demonstrating the specific bacterial dispersal capacities of these insects have been performed. This study determined that Salmonella acquired internally, commonly transits the gut, allowed the insect to disperse viable pathogenic bacteria within 2-3 h.

Diet Restriction May Be Associated with Disturbances in GI Physiology in Adolescents with Irritable Bowel Syndrome: A Pilot Study

Purpose: Many patients who suffer from irritable bowel syndrome (IBS) report adverse reactions to foods and use diet restriction and food avoidance as a way to cope with their symptoms. Diet restriction reduces pain associated with eating but repeated fasting can also cause motility disturbances (Zipfel et al. Autonomic Neurosecience 2006) which can possibly increase other IBS symptoms such as constipation and bloating. The aim of the proposed pilot study is to investigate if motility disturbances are more common in IBS patients who habitually restrict their diets versus those who do not. Methods: Subjects were 8 IBS patients who habitually restrict their diet (defined as not eating ≧4 hours while hungry to control symptoms, ≧1 day/week, for at least 6 months; Patients who were trying to lose ≧ 5 lbs were excluded) and 6 IBS patients without diet restriction (Ages range 15-21, Mean=19.5; 69.2% female). Methods: Whole gut transit time was measured by radiopaque markers, gastric sensitivity was measured by water load test (drinking max of 800 ml of water in 5 minutes or until full) and an electrogastrogram was obtained 15 min before the water load test and 30 minutes postprandially. Results: Whole gut transit tended to be slower in the restrictors (M=51.0±23 hours) versus the non-restrictors (M=37.0±19 hours). Restrictors tolerated less water until feeling full (M=464.4±107ml) than non-restrictors (M=545±178ml). Bradygastria, tachygastria or mixed dysrythmias were found in 62.5% of restrictors and 66.6% of non-restrictors. None of these differences were significant due to small sample size. Conclusion: Initial results suggest that repeated diet restriction is associated with slower transit time and increased gastric sensitivity but not with abnormal gastric myoelectrical activity. A sample of N=72 (transit time) to N=102 (gastric sensitivity) is needed for 80% power. It remains to be determined if changes in GI physiology are also associated with changes in symptoms. [Supported by a clinical research award from the American College of Gastroenterology and UL1RR025747].

Assessment of Tandem Measurements of pH and Total Gut Transit Time in Healthy Volunteers

Assessment of Tandem Measurements of pH and Total Gut Transit Time in Healthy Volunteers

SmartPill technology provides safe and effective assessment of gastrointestinal function in persons with spinal cord injury

Spinal cord injury (SCI) results in gastrointestinal (GI) complications, including gastroesophageal reflux disease and constipation, but much of the data is based on older technology. GI transit times were determined in subjects with SCI using a new device called a SmartPill. Our principal goal was to assess whether this new technology can be applied in persons with SCI. SCI and age- and gender-matched able-bodied (AB) control subjects not taking proton pump inhibitors were studied. Following an 8-h overnight fast, subjects consumed 120 g EggBeaters (60 kcal), two slices of white bread (120 kcal) and 30 g strawberry jam (74 kcal). A pH calibrated SmartPill capsule was swallowed with 8 ounces of water, after which subjects fasted for an additional 6 h prior to consuming an Ensure Plus nutrition shake (350 kcal). Subjects remained fasted for an additional 2 h, after which time they resumed their regular diets. Twenty subjects with SCI and 10 AB control subjects were studied. Data are expressed as mean±s.d. Comparing the group with SCI to the AB control group, gastric emptying time (GET), colonic transit time (CTT) and whole gut transit time (WGTT) were prolonged (GET: 10.6±7.2 vs 3.5±1.0 h, P<0.01; CTT: 52.3±42.9 vs 14.2±7.6 h, P=0.01; WGTT: 3.3±2.5 vs 1.0±0.7 days, P<0.01). No complications or side effects were reported. Our results indicate that the SmartPill technology is a safe, non-invasive assessment technique that provides valid diagnostic information in persons with SCI.

Digestive toxicity in grass shrimp collected along an impact gradient

Ingested pollutants may elicit digestive toxicity following incorporation into consumer tissues. This post-assimilatory toxicity may include tissue damage influencing synthesis of digestive enzymes, gut transit time and absorption of nutrients as well as pollutants by the gut epithelium. This study investigated impacts of chronic field exposure on gut residence time (GRT), feces elimination rate (FER), extracellular digestive protease activities and gut pH in grass shrimp Palaemonetes pugio. Adult shrimp were collected from differentially impacted sites within the New York/New Jersey Harbor Estuary and fed prepared meals containing fluorescent or near-infrared markers and analyzed for digestive toxicity. Relationships between digestive parameters and assimilation efficiencies (AE) for Cd, Hg and organic carbon reported previously were also analyzed. Minimum GRT did not vary significantly for field-collected shrimp, but was positively correlated with Cd, but not Hg or carbon, AE. FER was not impacted by field exposure. Digestive protease activities exhibited a marked decrease in grass shrimp from impacted field sites relative to reference shrimp. Relationships between the assimilation of elements and digestive physiology in field-collected shrimp suggest that digestive plasticity (increasing GRT) may be important in compensating for post-assimilatory digestive toxicity (reduced protease activities) in order to maintain nutrient assimilation. Stress-induced variability in digestive function among grass shrimp populations may, in turn, enhance the assimilation of non-essential elements, such as Cd.

Dose-response effect of Bifidobacterium lactis HN019 on whole gut transit time and functional gastrointestinal symptoms in adults

Objective. To assess the impact of Bifidobacterium lactis HN019 supplementation on whole gut transit time (WGTT) and frequency of functional gastrointestinal (GI) symptoms in adults. Material and methods. We randomized 100 subjects (mean age: 44 years; 64% female) with functional GI symptoms to consume a proprietary probiotic strain, B. lactis HN019 (Fonterra Research Centre, Palmerston North, New Zealand), at daily doses of 17.2 billion colony forming units (CFU) (high dose; n = 33), 1.8 billion CFU (low dose; n = 33), or placebo (n = 34) for 14 days. The primary endpoint of WGTT was assessed by X-ray on days 0 and 14 and was preceded by consumption of radiopaque markers once a day for 6 days. The secondary endpoint of functional GI symptom frequency was recorded with a subject-reported numeric (1–100) scale before and after supplementation. Results. Decreases in mean WGTT over the 14-day study period were statistically significant in the high dose group (49 ± 30 to 21 ± 32 h, p < 0.001) and the low dose group (60 ± 33 to 41 ± 39 h, p = 0.01), but not in the placebo group (43 ± 31 to 44 ± 33 h). Time to excretion of all ingested markers was significantly shorter in the treatment groups versus placebo. Of the nine functional GI symptoms investigated, eight significantly decreased in frequency in the high dose group and seven decreased with low dose, while two decreased in the placebo group. No adverse events were reported in any group. Conclusions. Daily B. lactis HN019 supplementation is well tolerated, decreases WGTT in a dose-dependent manner, and reduces the frequency of functional GI symptoms in adults.

In vivo determination of Daphnia feeding rates using PAM fluorometry

We examined the utility and sensitivity of PAM fluorometry as a tool for estimatingin vivo gut fluorescence and phytoplankton ingestion rates by Daphnia.KEYWORDS: ingestion; PAM fluorometry; zooplankton; gut pigmentsThe quantity, composition and rates of crustacean zoo-plankton feeding are used to quantify the trophic role ofthese animals in aquatic food webs. The most widelyused field and laboratory methods measure: (i) rate ofchange of the prey field (Gauld, 1951) and (ii) concen-tration of phytoplankton in the zooplankton gut(Mackas and Bohrer, 1976). Each approach has advan-tages and disadvantages (see Ba˚mstedt et al., 2000) andthe choice of method must consider the trade-offbetween information gained and implementationdifficulty.Clearance rate estimations are attractive becauseanimals need not be sacrificed and they can yield infor-mation on selectivity in terms of composition of theprey field. Recent methodological advances haveemployed tools including the FlowCAM (Ide et al.,2008) and the PhytoPAM (Lu¨rling and Verschoor, 2003)to reduce time-consuming microscopic analyses.However, these methods still indirectly measure materialactually ingested and are prone to error associated withovercrowding and sloppy feeding. On the other hand,direct measures of gut contents such as the gut fluor-escence technique are practical and simple: ingestionrate is calculated as the product of gut transit time(GTT) and content. Ingested phytoplankton biomass isestimated with solvent extraction followed by fluorome-try and GTT estimated as the rate of change of gutcontent for animals incubated in filtered water. Dietcomposition can further be measured using pigment-specific analysis (e.g. HPLC; Kleppel and Peiper, 1984;Quiblier et al., 1994). This approach has been widelyused in marine studies but criticized regarding thecorrect interpretation of the photosynthetic pigmentdegradation products in the gut (Ba˚mstedt et al., 2000).Although the gut fluorescence method is relativelysimple and thus attractive, tissue requirements may behigh (e.g. HPLC analyses; Kleppel and Peiper, 1984).Furthermore, solvent treatment is prohibitive when theobjective is to relate feeding to physiological statemeasurements (e.g. enzyme activity). An ideal methodwould permit accurate repeated measurement offeeding activity on the same individuals (or subset) asused for physiological measurements. Recent studieshave pursued non-destructive gut fluorescence measure-ments and demonstrate that in vivo (as opposed toextracted) measures of gut fluorescence represent poten-tially rapid and reliable estimates. Such methods havebeen used to estimate gut pigment content and GTTon

Do Smoking and Drinking Habits and Obesity Affect Prevalence of Colorectal Neoplasia in Patients With Positive Immunochemical Fecal Occult Blood Test?

G A A b st ra ct s tertiary center. Prolonged SBTT was defined as >6 hours. Regional and whole gut transit times were analyzed. For pts with slow SBTT, average amplitude (AUC) and frequency of contractions (Ct) 60 minutes before and after gastric emptying (GET) were analyzed and compared to the pressure profile of 66 healthy controls. Results: 77 pts underwent WMC test due to upper GI symptoms and suspected GI dysmotility. Of those, 10 pts (13%) had SB motility disorder with isolated prolonged SBTT, but normal gastric and colon transit times. Mean SBTT was 461 min (360-600), significantly longer than normal (p=0.001). The CTT in this group was not significantly different from healthy subjects. There was a tendency to have longer, although normal, mean GET 239 min (p=0.04), compared to healthy subjects. Pressure data: no significant differences were found between pts with isolated slow SBTT and healthy controls in Ct and AUC. The clinical presentation of the pts with isolated SBTT delay was analyzed. Upper GI symptoms were the most common: upper abdominal pain and discomfort -80%, bloating60%, nausea-50%, early satiation-50%, fullness sensation40%, vomiting30%, weight loss30%, abdominal distention-30%, loss of appetite20%, constipation50%. Two pts had DM. In all pts, extensive GI work up, including GES in 2 pts, was unrevealing prior to the WMC test. Following documenting of slow SBTT, in 50% of pts new treatment was initiated -3 pts were treated with lubiprostone, 2 pts were treated for SIBO. Conclusions: SB transit delay might be the underlining pathophysiology for GI symptoms in a subset of pts. Postprandial symptoms are the most common. Evaluation of SBTT by WMC might be considered for patients with upper GI symptoms resembling gastroparesis, in whom no other abnormality of GI tract was identified. An abnormal SBTT could serve as a target for treatment if found.

N-Acylphosphatidylethanolamines as Novel Regulators of Gastrointestinal Motility in the Mouse

Background: N-acylethanolamines (NAEs) are long chain fatty acid ethanolamides which are present in almost all mammalian tissues including the gastrointestinal (GI) tract. NAEs are synthesized from the hydrolysis of phospholipid precursors N-acylphosphatidylethanolamines (NAPEs) by N-acylphosphatidylethanolamine-hydrolyzing phospholipase D (NAPEPLD). Despite their abundance, the physiologic roles of C16:0 and C18:1 NAPEs in the GI tract are not known. They may induce their effects directly or by conversion to Npalmitoylethanolamine (C16:0) or N-oleoylethanolamine (C18:1). We examined whether i) C16:0 or C18:1 NAPE regulates GI motility in the mouse, and ii) if these effects are through the endocannabinoid system involving NAPE-PLD and the cannabinoid 1 (CB1) receptor. Methods: Wild type, NAPE-PLD -/or CB1-/mice were used. The effects of C16:0 and C18:1 NAPEs on contractility of the intestine to electrical field stimulation (EFS; 4Hz, 60 Volts) and bethanechol (10μM) were studied in an organ bath In Vitro. Whole gut transit of an Evans blue marker after treatment with NAPEs (1-10 mg/kg i.p.) was studied In Vivo. NAPE-PLD mRNA expression after treatment with NAPEs was measured by real-time PCR. Results: C16:0 NAPE (up to 10 μM) reduced EFS induced contractions by ~ 41% in the ileum and ~ 44% in the colon of wild type mice. C18:1 NAPE had no effect in either region of the intestine. AM251 (100nM), a CB1 antagonist, blocked the effect of C16:0 NAPE on EFS contractility in the ileum but not the colon. Organ bath experiments on CB1-/mice confirmed these findings, as C16:0 NAPE did not have any effect in the ileum of those mice; however, it was still active in the colon. In NAPE-PLD -/mice, the effect of C16:0 NAPE was completely abolished in the ileum but not the colon (~42% inhibition at 10 μM). C16:0 or C18:1 NAPE had no effect on contractions induced by bethanechol. C16:0 NAPE dose-dependently increased whole gut transit time with ~100% increase at 10 mg/kg compared to the vehicle treated mice. AM251 blocked this effect. C18:1 NAPE had no effect on whole gut transit up to 10mg/kg. C16:0 or C18:1 NAPE (50 mg/kg i.p.) did not change NAPE-PLD mRNA expression in either ileum or colon of wild type mice. Conclusion: C16:0 but not C18:1 NAPE modulates GI motility. This effect requires the conversion of the NAPEs to a CB1 receptor ligand by NAPE-PLD in the ileum, but it involves other pathways in the colon. This study suggests some NAPEs may have a role as physiologic regulators of GI motility.

Effect of diet and gut dynamics on the establishment and persistence of Escherichia coli

Escherichia coli population dynamics and diversity in rats fed diets differing in their crude fibre content were assessed. Female Wistar rats (n = 40) were fed diets containing 1, 4, 18 or 26 % crude fibre. Animals were housed in pairs, and one animal was inoculated with a phylogroup B1 strain of E. coli, the other with a phylogroup B2 strain. Natural strain transmission was allowed to occur between the animals in each cage. As expected, the diets had a significant effect on gut dynamics. Mean gut retention times were shorter in animals fed the 18 and 26 % crude fibre diets compared with animals on the low-fibre diets. The effect of diet on gastrointestinal dynamics in turn affected E. coli population dynamics and clonal composition. Animals fed the low-fibre diets had higher cell densities than animals fed the high-fibre diets. E. coli populations dominated by phylogroup B2 strains exhibited lower cell densities in animals fed the high-fibre diets compared with cell densities in animals fed the low-fibre diets. Overall, E. coli cell densities declined as gut transit times decreased. Results from this experiment support the results garnered from prospective studies examining the distribution of E. coli from hosts with differing diets, gut morphology and dynamics.

Prevalence of Irritable Bowel Syndrome in Northern India

Prevalence of Irritable Bowel Syndrome in Northern India

Nitric Oxide–Sensitive Guanylyl Cyclase Is Dispensable for Nitrergic Signaling and Gut Motility in Mouse Intestinal Smooth Muscle

The nitric oxide-guanosine 3',5'-cyclic monophosphate (cGMP) signaling pathway has an important role in the control of smooth muscle tone. NO is produced by NO synthases and acts as a major inhibitory neurotransmitter in the gastrointestinal (GI) tract. The main target, NO-sensitive guanylyl cyclase (NO-GC), is stimulated by NO to produce the intracellular messenger cGMP. We investigated the role of NO-GC in nitrergic relaxation and GI motility. We tested relaxation of GI smooth muscle in mice that do not express NO-GC or mice with disruption of NO-GC specifically in smooth muscle cells. Different segments of the GI tract (fundus, lower esophageal sphincter, pyloric sphincter, and duodenum) were used in isometric force studies. NO donors and electrical field stimulation were used to assess nitrergic signaling. Whole-gut transit time was measured as an indicator of GI motility. Mice that lack NO-GC do not have NO-induced relaxation of GI smooth muscle. Gut transit time was increased, resulting in GI dysfunction. Surprisingly, in mice that lack NO-GC specifically in smooth muscle, NO-induced relaxation was reduced only slightly, and whole-gut transit time was unchanged compared with wild-type mice. Lack of NO-GC in smooth muscle cells does not impair NO-induced relaxation of GI tissues or GI motility. The NO receptor guanylyl cyclase in GI smooth muscle is therefore dispensable for nitrergic signaling in mice.

Do experimental methods affect estimates of pollen digestion by birds?

Pollen protoplasts may supply important nutritional resources for birds; however, they are locked up within the mechanically strong and biochemically complex pollen wall. Previous studies of pollen digestion in birds have yielded highly variable and often contradictory results. We tested whether these differences could reflect the vastly different methodologies that have been used. We used a standard method to investigate digestion of Banksia grandis (Proteaceae) pollen in New Holland honeyeaters (Phylidonyris novaehollandiae). Four types of B. grandis pollen were examined: fresh, frozen for a week, stored in conditions to stimulate pregermination for 24 h, or collected by honeybees. Our data indicate that although pollen treatment may influence digestibility of the pollen grains, these differences do not reach statistical significance because they are dwarfed by a high degree of variability between birds fed the same diet as well as variability in gut transit time (generally more pollen grains were digested over longer transit times). Similar patterns were observed for red wattlebirds (Anthochaera carunculata) fed bee-collected pollen. We believe that feeding behaviour or gut transit time may explain the marked differences between previous studies of pollen digestion by nectarivores, particularly the conflicting results for New Holland honeyeaters.

Evaluation of an alternative to feeding whole frozen fish in belugas (Delphinapterus leucas)

Feeding fish to captive piscivores can be challenging owing to cost, availability, variability in nutrient, and caloric composition, as well as handling and storage concerns. This trial evaluated the response of three belugas to being fed Fish Analog, an alternative to frozen fish. Body condition, gut transit time, serum chemistry and metabolic hormone analytes, immune function, and behavioral motivation were the dependent variables. Belugas (n=3) were fed various levels of Fish Analog (0-50%) over a 6-month period, and follow-up studies were conducted to further examine several dependent variables. When provided in gradually increasing amounts, belugas consumed the Fish Analog, with only minor fecal consistency changes and without behavioral responses indicative of gastric discomfort. Axillary girth and blubber thickness were positively correlated, and did not differ significantly with changes in the percentage of Fish Analog fed. Individual animal variation in initial passage time, some serum chemistry analytes, and immune function differences were noted following feeding of Fish Analog. Feeding Fish Analog reduced blood n9 fatty acids compared with captive belugas fed no Fish Analog. Feeding a DHA-enriched Fish Analog increased several n3 fatty acids, including eicosapentaenoic acid, but not DHA, compared with whales fed no Fish Analog or non-DHA-enriched Fish Analog. Fish Analog was shown to be a viable alternative to feeding fish at up to 50% of the dietary caloric density.

The effects of increasing water content to reduce the energy density of the diet on body mass changes following caloric restriction in domestic cats

Caloric restriction induces body mass loss that is often regained when restriction ends. This study aimed to determine if dietary energy density modulates the extent of post-restriction body mass regain. Water (20% wt:wt) was added to a standard dry commercially available feline diet. Twenty-seven domestic short-haired cats underwent a 20% caloric restriction on this diet. Following restriction, cats were offered the same dry diet ad libitum either without additional water or with 40% added water, therefore maintaining macronutrient composition whilst manipulating energy density. Despite no significant difference in energy intake during ad libitum consumption, post-restriction body mass regain was greater on the high energy dense (0% hydrated), compared to the low energy dense (40% hydrated) diet. The same protocol was repeated with a separate cohort of 19 cats with additional measures of physical activity, gut transit time and energy digestibility. Activity levels on the low energy dense diet were significantly higher than in cats on the high energy dense diet (p=0.030) and were similar to those recorded during caloric restriction. These results suggest that body mass gain following caloric restriction is ameliorated, and physical activity enhanced, by feeding a diet which is low in energy density due to the addition of 40% water.

Evaluation of gastrointestinal transit in clinical practice: position paper of the American and European Neurogastroenterology and Motility Societies

Disorders of gastrointestinal (GI) transit and motility are common, and cause either delayed or accelerated transit through the stomach, small intestine or colon, and affect one or more regions. Assessment of regional and/or whole gut transit times can provide direct measurements and diagnostic information to explain the cause of symptoms, and plan therapy. Recently, several newer diagnostic tools have become available. The American and European Neurogastroenterology and Motility Societies undertook this review to provide guidelines on the indications and optimal methods for the use of transit measurements in clinical practice. This was based on evidence of validation including performance characteristics, clinical significance, and strengths of various techniques. The tests include measurements of: gastric emptying with scintigraphy, wireless motility capsule, and (13)C breath tests; small bowel transit with breath tests, scintigraphy, and wireless motility capsule; and colonic transit with radioopaque markers, wireless motility capsule, and scintigraphy. Based on the evidence, consensus recommendations are provided for each technique and for the evaluations of regional and whole gut transit. In summary, tests of gastrointestinal transit are available and useful in the evaluation of patients with symptoms suggestive of gastrointestinal dysmotility, since they can provide objective diagnosis and a rational approach to patient management.

Rate of soil egestion by larvae of Hylamorpha elegans (Burm.) and Phytoloema hermanni Germ. (Coleoptera: Scarabaeidae)

Larvae of Hylamorpha elegans (Burm.) and Phytoloema herrmanni Germ. feed on roots, although many Scarabaeidae species are able to feed and survive on soil without living roots. In this study we evaluated the potential of H. elegans and P. herrmanni to ingest soil by estimating the rate of soil egestion. In the laboratory, the rate of soil egestion was determined from gut content and gut transit time of 3rd-instar larvae feeding on soil without roots. The soil egestion rate was 14-21 mg g(-1) d(-1) for H. elegans and 11-16 mg g(-1) d(-1) for P. herrmanni. The gut transit time (time of soil passage from mouth to anus) was 2-3 d for both species and the gut content was 41±2 mg g(-1) for H. elegans and 32±2 mg g(-1) for P. herrmanni. The quantitative importance of feeding activity on soil depends upon the population density of larvae in the field, which ranges from 1 to 25 larvae m(-2), but in severe outbreaks can reach 300 larvae m(-2). High population densities could result in soil egestion rates reaching 20 kg d(-1) ha(-1) for P. herrmanni and 30 kg d(-1) ha(-1) for H. elegans.

Effect of water temperature on gut transit time, digestive enzyme activity and nutrient digestibility in yellowtail kingfish ( Seriola lalandi)

Yellowtail kingfish ( Seriola lalandi) are farmed in sea cages in South Australian waters and exposed to seasonal variations in water temperature. The temperature variations, ranging from 10 to 24 °C, influence feed intake and on-farm feeding practices. Sub-adult yellowtail kingfish are fed twice daily in summer while feeding in winter may be reduced to once every second day. Lower winter water temperatures increase gut transit times which may lead to a condition known as winter syndrome. This syndrome causes an enteritis response in yellowtail kingfish and reduces farm productivity. The impact of water temperature on gut transit time, nutrient digestibility and protease and lipase enzyme activities in yellowtail kingfish (2.12 ±0.03 and 2.77 ± 0.03 kg live weight in summer and winter respectively) was investigated at summer and winter water temperatures; 20.8 ± 0.4 °C and 12.6 ± 0.1 °C respectively, using observations made on dissected fish and detection of the passage of dietary markers. Water temperature had a significant effect on gut transit time, with visual observations demonstrating that at summer water temperatures it takes 12–16 h for all digesta to be voided from the fish compared to 36–48 h at winter temperatures. Temperature did not have a significant effect on the dietary nutrient apparent digestibility coefficients (ADC, %) although there was a numerical tendency for nutrient ADC to be higher in the posterior intestine at summer water temperatures: 46% vs. 35% for dry matter; 70% vs. 67% for protein; 66% vs. 58% for fat; and 70% vs. 63% for energy. Nutrient digestibility did not differ significantly between the anterior and posterior intestinal sections; however, the ADC values were consistently higher in posterior intestine. Protease activity was significantly higher in the posterior intestine and there was also a numerical, but not significant, increase in protease and lipase activities in the anterior section of the intestine during winter. Lipase activity was significantly higher in the anterior intestine during summer, when compared to the posterior section, and numerically higher in this section during winter. In winter it was found that a greater proportion of nutrient digestion occurred in the stomach, pyloric caeca and anterior intestine when compared to summer. This was thought to be due to the slower gut motility and higher enzyme activities observed during winter. Even though gut transit time was slower in winter, the lower water temperature also resulted in nutrient digestibility that was numerically lower.