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- Author or Editor: Joan Eisemann x
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Abstract
Objective
To identify the cause and mechanisms of injury in gastroesophageal ulcer disease in market weight swine.
Design
Comparison of mechanisms of injury caused by HCI with those caused by short chain fatty acids (SCFA) in gastric mucosa.
Animals
Pigs weighing 30 to 40 kg.
Procedure
Gastric tissues were studied in Ussing chambers; short-circuit current (Isc) and electrical resistance (R) were recorded in response to treatment, and tissues were examined histologically.
Results
60 mM mucosal acetate abruptly (≤ 75 minutes) and irreversibly abolished Isc at pH ≤ 4.5, whereas R decreased more slowly. These data were associated with cell swelling and vesicle formation in mid-zonal layers, followed by sloughing of the outer barrier, erosion into deeper zones, and finally, ulceration. Mucosal HCI at pH > 1.5 was ineffective; however, at pH 1.5, HCI induced an abrupt decrease in R, followed by a slow decrease in Isc, an effect opposite to that caused by SCFA. Serosal addition of HCI rapidly abolished Isc suggesting a barrier to free H+ diffusion from the mucosal solution.
Conclusions
Undissociated SCFA rapidly penetrate the outer barrier and acidify underlying viable tissue. Cellular acidification inhibits Na pumping and osmoregulation, resulting in cell swelling and necrosis. In contrast, HCI induces an increase in outer barrier permeability before accessing the transporting cells, a much longer process (≥ 5 hours) requiring a lower pH. These studies suggest that microbial production of SCFA may be important in the pathogenesis of porcine gastric ulcers. (Am J Vet Res 1996;57:564-573)
Abstract
Objectives
To determine effects of finely ground diet and food deprivation on pH and bile acid concentration in the proximal portion of the porcine stomach and effects of bile acids and pH on the pars esophageal mucosa in vitro.
Animals
Sixteen 15- to 30-kg pigs.
Procedures
Gastric content samples obtained from pigs fed a finely ground pelleted or coarsely ground meal diet were assayed for gastric pH and bile acids. Stratified squamous epithelium was studied in an Ussing chamber, and histologically. Electrical conductance and transmucosal mannitol fluxes (as indices of tissue permeability) were determined at pH 4.0, 2.0, and 1.5 and in response to treatment with 0, 1, 2, or 3 mM taurodeoxycholate or glycocholate.
Results
Pigs fed the finely ground feed had significantly (P = 0.01 ) lower proximal stomach pH than did pigs fed the coarse meal. Proximal stomach bile acids concentration was significantly (P = 0.04) higher in pigs fed the finely ground diet. The H+ and bile acids concentration increased with time after feeding. In vitro exposure of the stratified mucosa to high H+ (pH < 4.0) and bile salt concentration (≥ 1.0 mM) resulted in significant (P < 0.05) dose-dependent increase in tissue conductance and mannitol fluxes, whereas low pH or bile acids alone had little effect.
Conclusions
High H+ and bile acids concentration in the stomach of pigs fed finely ground diets or subjected to feed deprivation may contribute to ulceration of the pars esophageal tissue. Bile acids act synergistically and in dose-dependent manner, with low pH causing damage to the stratified squamous epithelium in vitro. (Am J Vet Res 1998;59:1170-1176)
Abstract
Objective—To determine whether withholding feed from pigs prior to slaughter had any effects on meat quality, percentage of pigs with Salmonella spp in cecal contents during slaughter, or percentage of pigs with lacerations of the gastrointestinal tract during slaughter.
Design—Split-plot design.
Animals—873 pigs.
Procedures—At the finishing barn, pigs were assigned to 30 pens. Feed withdrawal times were assigned to pens at random, and pigs in each pen were marketed in 3 groups. The first marketing group consisted of the 10 heaviest pigs in each pen, the second consisted of the next 10 heaviest pigs, and the third consisted of all remaining pigs.
Results—Withdrawing feed improved the redness score assigned to the meat but did not have any other significant effects on carcass composition or meat quality. The percentage of pigs with Salmonella spp in the cecal contents decreased from the first (73%) to the second (64%) to the third (52%) marketing group. However, isolation of Salmonella spp from cecal contents was not associated with feed withdrawal time or with pen prevalence of Salmonella shedding during the 2 months prior to slaughter. Feed withdrawal time and marketing group did not have any significant effects on overall prevalence of gastrointestinal tract lacerations.
Conclusions and Clinical Relevance—Results suggest that withdrawal of feed from pigs prior to slaughter does not increase the prevalence of Salmonella colonization or the risk of carcass contamination associated with gastrointestinal tract lacerations during slaughter but only slightly enhances meat quality. (J Am Vet Med Assoc 2002;220:497–502)
Abstract
Objective—To determine whether withdrawing feed from pigs prior to slaughter had any effects on prevalence or severity of gastric ulcers.
Design—Split-plot design.
Animals—873 pigs.
Procedures—At the finishing barn, pigs were assigned to 30 pens. Feed withdrawal times (0, 12, or 24 hours) were assigned to pens at random, and pigs in each pen were marketed in 3 groups over a period of 4 weeks. The first marketing group consisted of the 10 heaviest pigs in each pen, the second consisted of the next 10 heaviest, and the third consisted of all remaining pigs. Feed was withheld from all pigs in each pen prior to removal of each marketing group. Thus, feed was withheld once, twice, or 3 times for pigs in the first, second, and third marketing groups, respectively.
Results—Feed withdrawal time was not significantly associated with ulcer score at the time of slaughter. Ulcer scores and prevalence of chronic damage were higher in the third marketing group, regardless of feed withdrawal time. Prevalence of severe damage, prevalence of chronic damage, and prevalence of esophageal constriction increased as carcass weight decreased. No pigs died of gastric ulceration.
Conclusion and Clinical Relevance—Results suggest that withdrawal of feed from pigs prior to slaughter does not increase damage to the stomach and that repeated feed withdrawal does not result in fatal gastric ulceration. (J Am Vet Med Assoc 2002;220:503–506)
Abstract
Objective—To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs.
Animals—6 pigs weighing between 60 and 70 kg.
Procedure—A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination.
Results—Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination.
Conclusions and Clinical Relevance—Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination. (Am J Vet Res 2002;63:1076–1082)
