Inhibition of gastric acid secretion in the rat by high calcium

The effect of feeding a commercial feedstuff on gastric squamous gastric disease (ESGD) healing and prevention of recurrence

Feedstuffs are often recommended to mitigate potential damage from acid associated with equine squamous gastric disease (ESGD). In acidic conditions, pectin alters its structure to one like mucus and binds the stomach mucosa, whilst alfalfa has a strong intrinsic acid buffering capacity. The study aimed to determine whether feeding a commercial beet pulp/alfalfa/oat fibre mix aids ESGD healing and/or prevention of recurrence. Ten adult horses with naturally occurring ESGD were included. All animals were treated with omeprazole as per the attending veterinarian's recommendation and randomly allocated to also be fed a commercial beet pulp/alfalfa/oat fibre mix (1Kg/horse divided into 2 meals/day; n=5) or no additional feed (n=5) for one month. Gastroscopy was then repeated to assess response to therapy. If the ESGD had healed, omeprazole therapy was discontinued, and the commercial feed given to all horses for a further month. Gastroscopy was repeated to determine ESGD recurrence. The mean (±SD) age of the horses was 11.6 (±3.8) years; 4 mares and 6 geldings; various breeds were represented; and the median (range) initial ESGD grade was 2 (2-4). ESGD had healed (grade 0/4) in all animals after one month. After a further month, ESGD had recurred in significantly (p=0.04) more animals that did not receive the commercial feed initially (3/5; 60%; mean [range] ESGD grade 3 [0,4]) compared to those that did (0/5; 0%; mean [range] ESGD grade 0 [0,0]). Thus, the commercial beet pulp/alfalfa/oat fibre mix aided prevention of ESGD recurrence when fed during the healing and prevention phases.

Effects of two alfalfa preparations with different particle sizes on the gastric mucosa in weanlings: alfalfa chaff versus alfalfa pellets

Background

Feeding alfalfa hay is often recommended for its buffering components, like protein and calcium, to prevent lesions of the gastric mucosa in horses. Until now, there has been no information regarding the influence of alfalfa particle size on the gastric mucosa. The aim of this study was to investigate the effects of feeding two alfalfa preparations with different particle sizes (alfalfa chaff vs alfalfa pellets) in comparison with grass hay on the gastric mucosa in weanling horses. We hypothesized that feeding a high proportion of fine alfalfa particles would negatively impact gastric mucosa and that feeding long alfalfa chaff would improve gastric mucosal health in weanlings.

Results

Before weaning, the prevalence of gastric mucosa lesions (one or more lesions considering all locations in the stomach) was 84.3 %; at 14 days after weaning, it was almost 100 %. Before and after weaning, most of the lesions were found at the greater curvature of the squamous mucosa and at the lesser curvature. After weaning, gastric mucosal lesions at the pylorus were significantly more severe in the group fed alfalfa chaff (p = 0.002). In the other regions, no differences related to the feeding regimes were observed.

Conclusions

Feeding alfalfa failed to improve gastric mucosal lesion scores in weanlings. Furthermore, foals fed alfalfa chaff had higher lesion scores at the pylorus. Alfalfa leaves contain a superior protein source and high amounts of calcium and magnesium, providing extra nutritional advantages in growing horses. At this time, either traditional grass hay rations or grass hay with alfalfa pellets can be recommended.

Treatment and prevention of equine gastric ulcer syndrome

EGUS is a common problem in horses and foals. Acids are the important causative factors and current therapy targets the suppression of gastric HCl and creation of a permissive environment for ulcer healing. Diagnosis is based on history, clinical signs, gastroscopy, and response to treatment. Of the products available, only GastroGard (FDA approved) and ranitidine have been shown to be efficacious in the treatment of EGUS. Ranitidine is often associated with treatment failure as a result of incorrect dosing and lack of owner compliance, because of the three times daily dosing required. Also, EGUS occurs in critically ill neonatal foals, but the pathogenesis may be different than in adult horses and acid-suppressive therapy may not be as effective.

Evaluation of diet as a cause of gastric ulcers in horses

OBJECTIVE

To measure pH, volatile fatty acid (VFA) concentrations, and lactate concentrations in stomach contents and determine number and severity of gastric lesions in horses fed bromegrass hay and alfalfa hay-grain diets.

ANIMALS

Six 7-year-old horses.

PROCEDURE

A gastric cannula was inserted in each horse. Horses were fed each diet, using a randomized crossover design. Stomach contents were collected immediately after feeding and 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24 hours after feeding on day 14. The pH and VFA and lactate concentrations were measured in gastric juice Number and severity of gastric lesions were scored during endoscopic examinations.

RESULTS

The alfalfa hay-grain diet caused significantly higher pH in gastric juice during the first 5 hours after feeding, compared with that for bromegrass hay. Concentrations of acetic, propionic, and isovaleric acid were significantly higher in gastric juice, and number and severity of nonglandular squamous gastric lesions were significantly lower in horses fed alfalfa hay-grain. Valeric acid, butyric acid, and propionic acid concentrations and pH were useful in predicting severity of nonglandular squamous gastric lesions in horses fed alfalfa hay-grain, whereas valeric acid concentrations and butyric acid were useful in predicting severity of those lesions in horses fed bromegrass hay.

CONCLUSIONS AND CLINICAL RELEVANCE

An alfalfa hay-grain diet induced significantly higher pH and VFA concentrations in gastric juice than did bromegrass hay. However, number and severity of nonglandular squamous gastric lesions were significantly lower in horses fed alfalfa hay-grain. An alfalfa hay-grain diet may buffer stomach acid in horses.

Gastric acid secretion in the chicken: effect of histamine H2 antagonists and H+/K(+)-ATPase inhibitors on gastro-intestinal pH and of sexual maturity calcium carbonate level and particle size on proventricular H+/K+ ATPase activity

1. Cimetidine was more potent 4 hr after a single injection of 25 or 100 mg/kg body wt in increasing gastric pH than other H2 receptor antagonists, ranitidine and famotidine but was less efficient than H+/K(+)-ATPase inhibitors. Omeprazole rose proventricular and gizzard pH at a lower dose than SCH 28080 and Ro 18-5364 (30, 50 and 200 mg/kg body wt, respectively). 2. Proventricular and gizzard pH values were maximal 1 and 4 hr after a single injection of 7.5 mumol/kg body wt omeprazole. Inhibition of acid secretion was maintained for 24 hr after an injection of 100 mumol/kg. 3. H+/K(+)-ATPase activity in vitro was 10 mumol Pi/hr/mg protein in the microsomal fractions of the proventriculus. It was doubled by nigericine and inhibited by SCH 28080. However, western blots by high specific H+/K(+)-ATPase monoclonal antibody 95-A3 and 95-111 recognized a 42 kDa band but hardly exhibited the specific 95 kDa band recognition. 4. Chickens and immature pullets showed a higher H+/K(+)-ATPase activity than laying hens. Calcium level of the diet did not affect the enzyme activity but coarse particles of calcium fed to pullets or laying hens enhanced the H+/K(+)-ATPase activity when compared with ground particles.