Colonic Fluid and Electrolyte Transport in Health and Disease

Fecal Microbiota, Bile Acids, Sterols, and Fatty Acids in Dogs with Chronic Enteropathy Fed a Home-Cooked Diet Supplemented with Coconut Oil

Medium-chain fatty acids (MCFAs) are considered to be interesting energy sources for dogs affected by chronic enteropathies (CE). This study analyzed the clinical scores, fecal microbiota, and metabolomes of 18 CE dogs fed a home-cooked diet (HCD) supplemented with virgin coconut oil (VCO), a source of MCFA, at 10% of metabolizable energy (HCD + VCO). The dogs were clinically evaluated with the Canine Chronic Enteropathy Activity Index (CCECAI) before and at the end of study. Fecal samples were collected at baseline, after 7 days of HCD, and after 30 days of HCD + VCO, for fecal score (FS) assessment, microbial analysis, and determination of bile acids (BA), sterols, and fatty acids (FA). The dogs responded positively to diet change, as shown by the CCECAI improvement (p = 0.001); HCD reduced fecal fat excretion and HCD + VCO improved FS (p < 0.001), even though an increase in fecal moisture occurred due to HCD (p = 0.001). HCD modified fecal FA (C6:0: +79%, C14:0: +74%, C20:0: +43%, C22:0: +58%, C24:0: +47%, C18:3n-3: +106%, C20:4n-6: +56%, and monounsaturated FA (MUFA): -23%, p < 0.05) and sterol profile (coprostanol: -27%, sitostanol: -86%, p < 0.01). VCO increased (p < 0.05) fecal total saturated FA (SFA: +28%, C14:0: +142%, C16:0 +21%, C22:0 +33%) and selected MCFAs (+162%; C10:0 +183%, C12:0 +600%), while reducing (p < 0.05) total MUFA (-29%), polyunsaturated FA (-26%), campesterol (-56%) and phyto-/zoosterols ratio (0.93:1 vs. 0.36:1). The median dysbiosis index was <0 and, together with fecal BA, was not significantly affected by HCD nor by VCO. The HCD diet increased total fecal bacteria (p = 0.005) and the abundance of Fusobacterium spp. (p = 0.028). This study confirmed that clinical signs, and to a lesser extent fecal microbiota and metabolome, are positively influenced by HCD in CE dogs. Moreover, it has been shown that fecal proportions of MCFA increased when MCFAs were supplemented in those dogs. The present results emphasize the need for future studies to better understand the intestinal absorptive mechanism of MCFA in dogs.

Myths and misconceptions about childhood constipation

Many widely held beliefs and assumptions concerning childhood constipation continue to interfere with rational management of childhood constipation. Although many still believe that constipation is not a common disease, about 9.5% of the world's children suffer from chronic constipation. Most of these children live in non-Western countries. There are major misconceptions about the etiology of constipation as a significant proportion of clinicians still believe that constipation is caused by some form an organic pathology, whereas in reality, the majority have functional constipation. Contrary to a commonly held belief that children outgrow constipation without long-term problems, there is evidence that constipation leads to significant bowel and psychological consequences and has a major impact on the quality of life which detrimentally affects future health and education. Finally, ineffective management strategies such as increasing fiber and water in the diet, and short duration of treatment owing to the fear that long-term laxative treatment leads to colonic dysfunction, interfere with effective therapeutic strategies.   Conclusions: It is apparent that myths and misconception often lead to wrong assumptions regarding the distribution of the disease, its etiology, pathophysiology, and management leading to ordering incorrect investigations and ineffective therapeutic strategies while spending large sums of public funds unnecessarily. Poorly treated constipation leads to deleterious psychological consequences predisposing children to develop significant psychological damage and bowel dysfunctions. This review aims to challenge these myths about various elements of constipation by exploring the existing literature and encouraging clinicians to have a fresh look at old concepts that could interfere with the well-being of children with constipation. What is Known: • Childhood constipation is a growing problem in the world leading to significant suffering and high healthcare expenditure • Myths and misconceptions lead to poor management strategies causing psychological and bowel damage What is New: • Organic, systemic, and bowel disorders leading to constipation are uncommon, and in the majority, it arises due to deliberate fecal withholding and most investigations ordered by clinicians are not very helpful in the management • Most non-pharmacological interventions are not effective in the day-to-day management of childhood constipation. The use of laxatives is considered to be the first-line management strategy.

Grading fecal consistency in an omnivorous carnivore, the brown bear: Abandoning the concept of uniform feces

Grading the fecal consistency of carnivores is a frequently used tool for monitoring gut health and overall digestion. Several fecal consistency grading systems are available for mainly felids and canids. No such system exists for the brown bear (Ursus arctos Linnaeus, 1758). We aim at extending current fecal consistency grading systems with a scoring system for brown bears. The system was set up during a diet study with nine individuals fed a variety of diets including beef meat, rabbit, fruit, and grass-fruit-pellet mix in an incomplete crossover design. One additional individual was included opportunistically and was fed the typical zoo diet (vegetable-fruit-meat-pellet diet). All feces from the collection period were photographed, graded by "handling the feces" and visually inspected for dietary components. Based on a total of 446 feces, a six-point scale for uniform fecal consistencies was established. In 11% of all feces, two distinct consistencies could be distinguished, a feature that appears in other carnivore species as well. Hence, an additional grading system for dual consistencies was developed. The fecal consistency of brown bears is heavily dependent on the diet items processed before defecation with the general observation that the more vegetation or whole prey, the firmer the feces, and at certain proportions of the latter, the higher the chance for dual fecal consistencies to occur. The results indicate that in bears, diet may have a strong effect on fecal consistency, hampering animal health assessments without prior knowledge of the diet.

Er Shen Wan extract reduces diarrhea and regulates AQP 4 and NHE 3 in a rat model of spleen-kidney Yang deficiency-induced diarrhea

INTRODUCTION

Er Shen Wan (ESW), a traditional Chinese medicinal formula comprised of Psoraleae Fructus (Babchi seeds, from Psoralea corylifolia Linn.) and Myristicae Semen (Nutmeg, from Myristica fragrans Houtt.), is widely used to treat spleen-kidney Yang deficiency (SKYD)-induced diarrhea. Previous studies have demonstrated preliminarily that the petroleum ether extract of ESW (ESWP) exhibits significant anti-diarrheal activity. The present study aimed to evaluate the anti-diarrhea activity of ESWP and to explore the underlying mechanisms with respect to fluid metabolism in a rat model of SKYD-induced diarrhea.

MATERIALS AND METHODS

A high-performance liquid chromatography-diode array detector (HPLC-DAD) approach was developed and validated for qualitative and quantitative analyses of the main constituents of ESWP. SKYD model rats were established and treated with an effective dose (3.5?g/kg) of the extract for two weeks. Anti-diarrheal activity and stool properties were observed. After the experiment, the appearance and histology of the intestines were evaluated. Serum levels of neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) were also determined. Furthermore, to characterize the regulation of aquaporin-4 (AQP 4) and Na⁺/H⁺ exchanger isoform 3 (NHE 3) in the colon, quantitative real-time RT-PCR (qRT-PCR), immunohistochemistry (IHC) and Western blotting (WB) were employed to detect mRNA and protein expression levels.

RESULTS

In the rat models, oral ESWP administration significantly reduced the diarrhea score and the number and weight of wet stools. Jejunal and ileac histological damage was impeded, and the histology score decreased. Serum VIP levels were significantly decreased, in contrast to NPY levels. In addition, AQP 4 and NHE 3 expression levels increased significantly.

CONCLUSIONS

These results showed that ESWP's anti-diarrheal effect might at least partially involve the regulation of hormones intimately involved in maintaining fluid and electrolyte levels, as well as by increasing AQP 4 and NHE 3 expression levels and enhancing the absorption of Na⁺ and water.

Digestive sensitivity varies according to size of dogs: a review

Field observations on food tolerance have repeatedly shown that when fed an identical diet, large breed (>25 kg) dogs present softer and moister faeces than small breed ones (<15 kg). The purpose of this review is to highlight the findings of four PhD theses, carried out between 1998 and 2013, whose objectives were to investigate the anatomical and physiological peculiarities that would explain, at least in part, this observation, as well as their nutritional implication. This work showed that large breed dogs, in contrast with smaller breeds, present a highly developed caecum and colon, which could explain the relatively longer colonic transit time. A prolonged colonic transit time could explain higher colonic fermentative activity, as supported by higher faecal concentrations of fermentative by-products. This effect would be reinforced by increased intestinal permeability and reduced sodium net-absorption. Taken together, these elements could be a possible cause of higher digestive sensitivity in large breed dogs. When prescribing a diet to a small or large breed dog, several aspects of the formulation must be taken into account. For a large breed dog, the general goal is to limit any ingredient that could increase the level of fermentable undigested residues and, in fine, exacerbate colonic fermentation. Highly digestible sources of proteins and starches are therefore strongly recommended to maintain an optimal digestive tolerance. Fermentable fibre sources (i.e. beet pulp and FOS) must also be used in limited quantity in their diet. Conversely, the incorporation of non-fermentable fibre (i.e. cellulose) appears useful to increase their stool quality. For a small breed dog, the general objective is to minimize any ingredient that could excessively limit colonic fermentation and induce in fine constipation. Purified starches and cellulose are therefore not really suitable for them. In contrast, cereals flours as well as non-fermentable fibre provided by cereals are recommended.

Evaluation of association between body size and large intestinal transit time in healthy dogs

OBJECTIVE

To compare large intestinal transit time (LITT) in dogs of various body sizes and determine whether fecal quality was correlated with LITT.

ANIMALS

6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes.

PROCEDURE

LITT was calculated as the difference between total (TTT) and orocecal transit time (OCTT). Minimum and mean OCTTs were determined by use of the sulfasalazine-sulfapyridine method. Minimum TTT was estimated by use of chromium and ferric oxide as color markers, and mean TTT was calculated from the recovery from feces of ingested colored plastic beads. Fecal moisture content was determined and fecal consistency was scored during the same period.

RESULTS

Large-breed dogs had higher fecal moisture content and more watery fecal consistency. No association between body size and OCTT was detected, but there was a positive correlation between body size and mean TTT. Mean LITT increased significantly with body size, from 9.1 +/- 1.1 hours in Miniature Poodles to 39.4 +/- 1.6 hours for Giant Schnauzers. Significant correlations were detected among mean LITT, mean TTT, and fecal scores, whereas no correlation was observed between fecal moisture content and TTT or LITT.

CONCLUSIONS AND CLINICAL RELEVANCE

LITT was correlated with fecal consistency in dogs of various body sizes. Mean LITT can be predicted from values for mean TTT in healthy dogs.

Relationship between total transit time and faecal quality in adult dogs differing in body size

Fed the same diet, large and giant-breed dogs have higher faecal moisture and increased frequency of soft stools than small ones. This could be the result of physiological differences, such as a different gastrointestinal transit time. In this study, we have correlated mean total transit time (MTT) with body size and faecal consistency in dogs varying in body size. Fifty dogs from 13 different breeds were used, from a Dachshund to a Great Dane. The MTT was determined using coloured plastic beads [Cummings and Wiggins, Gut, Vol. 17 (1976), p. 219], and faecal consistency was scored daily during the study. We confirmed the strong correlation between height at the shoulder (body size) and faecal score (r = 0.76; p < 0.0001). The MTT increased with body size, from 22 h for a Miniature Poodle to 59 h for a Giant Schnauzer. We found significant positive correlations (p < 0.0001) between MTT and body size as well as faecal scores (r = 0.71 and 0.70 respectively). In the present study, we observed an effect of body size on MTT. In our 50 healthy dogs a longer MTT was related to a poorer faecal quality. Previous studies reported no relationship between body size and the upper gastrointestinal transit time in healthy dogs. So, we hypothesized that body size would mainly affect colonic transit time and that a longer colonic residence time would be related to a poorer faecal quality by promoting fermentation activity.

Evaluation of Th1, Th2 and immunosuppressive cytokine mRNA expression within the colonic mucosa of dogs with idiopathic lymphocytic-plasmacytic colitis

The objective of this study was to evaluate the expression of the immunoregulatory and pro-inflammatory cytokines interleukin (IL)-2, IL-4, IL-6, IL-12p35, IL-12p40, interferon-gamma (IFN-gamma), and tumour necrosis factor-alpha (TNF-alpha), and the expression of the predominantly immunosuppressive cytokines transforming growth factor-beta (TGF-beta) and IL-10 in canine idiopathic lymphocytic-plasmacytic colitis (LPC). Semi-quantitative reverse transcriptase-polymerase chain reactions were performed using specific primers on RNA isolated from the colonic mucosa of healthy dogs, dogs with clinical signs of large intestinal disease but normal histopathology of the colon, and dogs with LPC. Canine LPC was associated with over-expression of IL-2 compared to healthy colonic mucosa (p<0.01) and the mucosa of dogs with large intestinal diarrhoea but normal histopathology (p<0.05). Higher levels of TNF-alpha mRNA were also seen in LPC compared to healthy mucosa (p<0.05). These results indicate that LPC is associated with activation of CD4+ T-helper lymphocytes and increased production of T-helper-1-type cytokines.

Relationship between faecal character and intestinal transit time in normal dogs and diet-sensitive dogs

The relationship between stool character and whole gut transit time (WGTT), which is the average time for the passage of material through the lumen of the alimentary tract from ingestion to defecation, was studied in eight control dogs and 12 dogs with non-specific dietary sensitivity. Dogs were fed four diets in a cross-over design, and faecal quality was assessed daily and WGTT determined using plastic pellets. Faecal quality was unaffected by diet in the control dogs. Dogs with dietary sensitivity produced looser faeces compared with the control dogs, and this was significant for two of the diets. There was no significant effect of diet on mean WGTT within or between groups. Minimum WGTT, which was the interval to the first appearance of markers in faeces, was shorter in sensitive dogs compared with controls, and this was significant for two of the four diets. There were significant, inverse relationships between minimum WGTT and both mean faeces score and percentage unacceptable defecations. These data suggest that rapid transit of certain dietary components may impact negatively on stool quality and contribute to loose faeces in dogs with non-specific dietary sensitivity.