Herd Level Risk Factors for Stomach Ulcers in Finishing Pigs

In an oral presentation by M. E. Busch, SEGES Pig Research Centre and E. Okholm Nielsen, Danish Veterinary and Food Administration, Denmark, it was noted that the influence of feed structure and pelleting on the development of gastric ulcers in pigs is well established.

Some studies have shown a beneficial effect of access to straw on gastric health. However, the role of other factors, e.g. disease and stress, is not well understood. The aim of this study was to identify herd factors associated with a high prevalence of gastric ulcers in finishing pigs. Based on results from earlier studies, it was decided to focus on feed type, infectious diseases, the use of straw and the floor type in the pens.

The managers of 37 Danish finishing farms answered a questionnaire about housing, feed, health and management on their farms. The farms were originally selected for a study on mortality, and they all had either a very low (21 farms) or a very high mortality (16 farms).

The stomachs of 20 pigs per farm were examined macroscopically at slaughter, and pathological changes in the esophageal part of the stomach were scored on a scale from 0 to 10 (score 0: no changes, score 1-5: parakeratosis/erosion, score 6-10: ulcer/fibrosis).

The association between the risk of having a stomach score of 6-10 and potential risk factors at the herd level was analysed by logistic regression analysis (PROC LOGISTIC, SAS).

The explanatory factors were: feed type, herd health status with regard to Actinobacillus pleuropneumoniae serotypes 2 and 6 (App 2 or App 6), PCV2-vaccination, access to straw) and type of pen floor In addition, mortality level was included as an explanatory factor in the final statistical model.

The prevalence of stomachs with a score of 6-10 was 51% in herds with low mortality and 62% in herds with high mortality, but the difference was not statistically significant. The use of pelleted feed (OR=3.7), PCV2-vaccinated pigs (OR=1.9) and the herd infection with App 6 (OR=1.6) were associated with an increased risk of a stomach score of 6-10 (p<0.05).

No effects of App 2 infection, straw or floor type were found.

The study confirmed the negative effect of pelleted feed. PCV2-vaccinated pigs had an increased risk of having stomach ulcers, probably because it is more common to PCV2-vaccinate in herds with stomach ulcer problems.

The association between App 6 infection and stomach ulcers supports the results of an earlier Danish study, in which an association between pleurisy and stomach ulcers was found.

Coarse Barley in Pelleted Diets for Pigs Reduces Gastric Ulcers

The use of finely ground diets improve technical performance parameters like average daily weight gain (ADG) and feed conversion ratio (FCR). However, the use of fine ground diets is a risk factor for the formation of gastric ulcers in swine, which have a negative effect on animal welfare.

The objective of this study, presented in a poster session by R. Jansen and colleagues, ForFarmers, Netherlands, is to improve animal welfare by reducing stomach ulcers without negative effects on animal performance parameters like FCR and ADG.

At a commercial finishing pig farm (Topigs 50 x Piëtrain; intact boars and gilts; n=880) finishers were allocated to either a control or the treatment group at the start of finishing at 25 kg of weight. Pigs in the control group received commercial fine ground barley and wheat based diets.

Pigs in the treatment group received exactly the same diet, with the difference that 15% of the fine ground barley was replaced by coarse ground barley. Feeds were analyzed for nutrients and for particle size distribution (wet sieve analysis).

Pigs were weighed at 0, 35, 70 and 105 days of finishing. The amount of feed supplied per pen was measured by a computer controlled dry feed installation and FCR was measured per two adjacent pens (n= 20 per treatment).

To assess the effect on gastric ulcers, one batch of pigs was evaluated at slaughter using a 0-7 scoring system of the pars esophagus building up from a smooth epithelium (0) towards different degrees of parakeratosis (1-3), different degrees in erosions and ulcers (4-6) until stenosis (7).

In total 99 stomachs (47 control, 52 treatment) were scored and photographed. Stomachs of the trial group had a significant (P<0.001, Mann Whitney U) lower severity of stomach ulcers with an average score of 2.64 compared to the control group with a average score of 4.14.

Odds ratio for a stomach score <4 was 0.07 (p<0.005) for the trial group. Technical performance did not differ between the control and treatment group (FCR 2.47 vs 2.49 p=0.49; ADG 869 vs 867 gram/day p= 0.85).

Partial replacement of fine ground by coarse ground barley in pelleted diets decreases the amount of stomach ulcers. This is a sustainable way to improve animal welfare of finishing pigs without increasing the use of raw materials resulting in an equal carbon footprint and economic performance.

Offering Different Roughages to Fattening Pigs: Effects on Gastric Health

Poster session by F. von Und Zur Mühlen and colleagues from the University of Veterinary Medicine Hannover, and the Chamber of Agriculture North Rhine-Westphalia, Germany.

Gastric ulcerations are a special challenge in modern pork production. Stress can be a reason but, in particular, the existing milieu of conditions have an impact on the development of gastric lesions. The dietetic effects of fibre sources in pigs’ gastrointestinal tract are well known. In some cases, fibre sources are used as material for the pigs to root and manipulate.

The present study was focused on the amount ingested when fibre sources are offered and whether there is an influence on gastric health.

In total 170 weaned pigs (bw: 27.0±2.79 kg) were housed individually and had free access to water. A commercial pelleted diet (ME: 13.5 MJ/kg as fed, XP: 17.2/16.8/15.9 %, XF: 3.8-4.4 %) was fed in three phases.

Eight groups were formed in which different types and amounts of additional crude fibre source were offered:

- control (C)
- 15 g straw (S)
- 15, 50, 100 g straw (S+)
- 15, 50, 100 g straw pellets (SP)
- 10, 30, 50 g palm kernel meal (P)
- 30, 75, 100 g palm kernel meal (P+)
- 100, 175, 200 g whole plant corn silage (CS)
- 200, 400, 600 g whole plant corn silage (CS+) in the respective phase.

Wet sieve analysis of the pelleted diet was performed. Feed intake of fibre source was recorded over the whole fattening period. After feed was withheld overnight pigs were slaughtered (after leaving farm) at the end of fattening (bw: 121±3.88 kg) and stomachs were examined. The mucosa of the pars nonglandularis was scored macroscopically with a five-step scoring system.

The fraction of particles >1.00 mm was 38.1, 39.1 or 28.7 % and the amount of particles smaller than 0.20 mm reached 29.9, 31.2 or 39.2 % in the diet of 1st, 2nd or 3rd phase of fattening.

During the entire fattening period the intake of fibre sources (S/S+/SP/P/P+/CS/CS+) varied with 0.410/0.632/1.79/1.23/1.74/5.79/8.59 kg as fed.

Compared to the total offered amounts, the consumption of fibre source reached 26.0/8.67/24.2/31.5/21.2/32.7/17.6 %.

Especially in SP the amount consumed varied highly. No single animal in any group ingested more than 57 % of the offered fibre source. Independent of the groups and the fibre consumption, 95 % of the animals were affected by marked stomach lesions (erosion, ulceration).

The uptake of corn silage was highest compared to the other fibre sources indicating that palatability influences the amount of ingested roughage. There was no prophylactic effect of roughages on gastric health.

This investigation did not indicate any desired effect of fibre source or amount of consumption on gastric health. When there are large amounts of fine particles in the diet the additional offer of roughage cannot prevent the deficiency in gastric health.

Swine Helicobacteriosis: Injuries in Stomachs of Piglets

Poster session by R. L. Silveira and colleagues from Fluminense Federal University, and several other Brazilian universities.

Gastric ulcer is a major cause of sudden death in swine, being multifactorial, involving animals raised intensively and confined. Helicobacter suis has been linked to this disease, thus becoming a major problem for pig farmers and industry. The aim of this study was to relate the pathological findings of subclinical gastric lesions that occur naturally in piglets, with the presence or absence of Helicobacter spp.

Forty-eight piglets were studied, with an average weight of 33 kg and average of 78 days old, acquired in a commercial farm, which after slaughter have had their stomachs collected and evaluated. Samples of aglandular, and glandular anatomical regions were collected for histopathologic and immunohistochemical evaluation.

Macroscopically, 34 (70.83%) animals had lesions on an aglandular region, while 14 (29.17%) had nothing. Microscopically, 44 animals (91.66%) showed parakeratosis. Of these, 22 were discreet, 20 moderate and two severe.

In the glandular region in 41 (85.4%) animals, there was a change in at least one of the three regions, and only seven animals (14.6%) showed no change in any of the three. The lesions were higher in the antral and cardia regions, followed by the fundus.

In relation to immunohistochemistry, 21 animals were negative in all areas, 24 positive in at least one, and none were positive in all.

The findings showed a relationship with the bacteria, and its immunostaining not associated with gastric lesions in certain regions demonstrates its saprophytic and opportunistic character.

Fusobacterium gastrosuis: New Species Prevalent in Pigs with Gastric Ulcers

A poster presentation by F Haesebrouck and colleagues from Ghent University and Université de Liège, Belgium stated that Helicobacter suis may play a role in gastric ulcer disease, possibly by affecting gastric acid secretion and by modifying the composition of the gastric microbiota.

In a recent metagenomics study, an unidentified Fusobacterium sp. was present in higher numbers in the stomach of H. suis infected than non-infected pigs.

Sixty stomachs from 6-8 months old pigs and adult sows were collected in slaughterhouses. Swabs were taken from each stomach region and streaked agar plates. After anaerobic incubation during 3 days, 9 isolates of a putative new Fusobacterium sp. were obtained. All isolates originated from pigs with ulcers.

Seven isolates were obtained from the pars esophagea, one from the cardia and one from the antrum. All isolates were phenotypically and genotypically characterized.

The 16S rRNA gene sequence showed 96% similarity with F. mortiferum and 95% with F. necrogenes, its closest phylogenetic neighbours.

The novel species, for which we propose the name Fusobacterium gastrosuis, can be clearly differentiated from its nearest phylogenetic neighbours.

Whole-genome sequencing and quantification of colonization levels in a larger number of animals are currently being performed. This, as well as experimental infection studies, should allow to obtain better insights in the potential role of this microorganism in the development of gastric pathologies in pigs, since most known Fusobacterium species are indeed considered to be pathogens.