Factors influencing the structure and function of the small intestine in the weaned pig: a review

There are not many data available on antibiotics used solely in animals and almost exclusively for growth promotion. These products include bambermycin, avilamycin, efrotomycin, and the ionophore antibiotics (monensin, salinomycin, narasin, and lasalocid). Information is also scarce for bacitracin used only marginally in human and veterinary medicine and for streptogramin antibiotics. The mechanisms of action of and resistance mechanisms against these antibiotics are described. Special emphasis is given to the prevalence of resistance among gram-positive bacteria isolated from animals and humans. Since no susceptibility breakpoints are available for most of the antibiotics discussed, an alternative approach to the interpretation of MICs is presented. Also, some pharmacokinetic data and information on the influence of these products on the intestinal flora are presented.

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Antimicrobial Growth Promoters Used in Animal Feed: Effects of Less Well Known Antibiotics on Gram-Positive Bacteria

http://www.aasp.org/shap/issues/v5n5/index.html ostweaning multisystemic wasting syndrome (PMWS) is a new disease first described in 1996.1,2 In the past 6–8, months the number of affected herds has grown considerably, and there are now confirmed cases in Alberta, Saskatchewan, Manitoba, Quebec, California, Iowa, Indiana, and Spain. Furthermore, since 1994, a similar syndrome—”wasting disease of piglets”—has been confirmed in as many as 200 herds in France.

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Recognizing and diagnosing postweaning multisystemic wasting syndrome (PMWS)

We evaluated the effects of a plant extracts mixture (XT) standardized in 5% (wt/wt) carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin (oregano, cinnamon and Mexican pepper), alone or in combination with formic acid (FA), on the productive performance and the intestinal ecosystem of the early-weaned pig. Pigs weaned at 20 +/- 1 d of age (n = 216) were allocated in 24 pens and fed a standard medicated prestarter diet for 12 d. Twelve days after weaning, a stress management system based on social and dietary stress factors was applied to the animals, after which, each group was allocated to one of six dietary treatments, which followed a factorial arrangement, with three levels (as-fed basis) of the XT (0, 150, and 300 mg/kg) and two levels of FA (0 and 0.5%). On d 24 and 25 after the stress episode, eight pigs per treatment were killed to examine variables describing some aspects of the gastrointestinal ecology. Two days after the stress episode, an Escherichia coli K88 diarrhea episode occurred, and five casualties were registered. Four of the five deaths occurred in pens of pigs not fed the XT. The FA resulted in better G:F (P = 0.040) in coincidence with shorter villous height (P = 0.073) and lower rectal total microbial mass (P = 0.078). Both XT and FA addition increased stomach content (P = 0.006 and 0.003, respectively) and percentage of DM (P = 0.089 and 0.010, respectively), suggesting an increased gastric retention time; consequently, pH was also increased (P = 0.005 and 0.060, respectively). The XT decreased ileum total microbial mass (P = 0.025) and increased the lactobacilli:enterobacteria ratio (P = 0.002). The VFA profile in the cecum and colon was modified by XT inclusion, increasing the proportion of acetate (P = 0.018 and 0.025, respectively) and diminishing the proportion of butyrate (P = 0.096 and 0.040, respectively) and valerate (P = 0.001 and 0.039, respectively). Both XT and FA were shown to be effective in modifying the gastrointestinal ecosystem, stomach contents, and stomach emptying rate, which are proposed as important aspects in the mechanisms of action for these additives.

Effect of Plant Extracts and Formic Acid on the Intestinal Equilibrium of Early-Weaned Pigs

Performance of growing-finishing pigs fed medium or high-fibre diets supplemented with avilamycin, formic acid or formic acid-sorbate blend.

Social and environmental stressors during the critical period of weaning frequently affect not only performance but also the health status of piglets. Pigs unable to cope with the changes associated with weaning develop a condition characterized by slowing of growth and a listless or unthrifty appearance, known as the wasting pig syndrome (WPS). In the present investigation a total of 100 4-week-old wasting pigs were studied. The pigs were divided randomly into 10 pens (10 animals per pen). Half the number of pigs were treated orally with amperozide (2.5 mg/kg body-weight), a psychotropic drug shown to modify emotional behaviour in response to social stress. Control groups were treated with long-acting oxytetracycline and vitamins (A + D3 + E). There were significant improvements in average daily weight gain (P less than 0.05) and feed conversion ratio (P less than 0.01) in amperozide-treated pigs compared with controls. Furthermore, there was a significant reduction (P less than 0.05) in mortality in amperozide treated groups. Within 2 weeks following amperozide treatment the clinical signs of the WPS had disappeared and the pigs grew at the same rate as normal healthy pigs.

Wasting pig syndrome (WPS) in weaners — treatment with amperozide

Avilamycin, an oligosaccharide antibiotic with growth-promoting properties in pigs, has proved to be effective in controlling stress-induced post-weaning diarrhoea in piglets, caused mainly by Escherichia coli. The present study includes two trials, in which 400 newly-weaned piglets were used (200/trial). The following five different treatments were tested; 0, 40 and 80 p.p.m. avilamycin, 50 p.p.m. olaquindox and 100 p.p.m. apramycin. In each trial there were four pens (each with five females and five males) per treatment. Avilamycin when given at 80 p.p.m. reduced average daily diarrhoea score (ADDS) and mortality, and improved liveweight gain and feed conversion ratio (FCR), compared with the untreated controls, the 40 p.p.m. avilamycin and the 50 p.p.m. olaquindox (P less than 0.05) treatments. The overall performance of 40 p.p.m. avilamycin and 50 p.p.m. olaquindox was similar. The results indicate that avilamycin at the dose level of 80 p.p.m. in the starter feed can control post-weaning diarrhoea of piglets and prevent loss of productivity. Nevertheless, the antibiotic apramycin, whose spectrum of activity is mainly against the Gram-negative bacteria, given at the therapeutic level of 100 p.p.m., was more effective than any other experimental treatment (P less than 0.05), except for ADDS and FCR which were not significantly different from that of avilamycin 80 p.p.m.

S. C. Kyriakis

Papers

Wasting pig syndrome (WPS) in weaners — treatment with amperozide

The effect of avilamycin in the control of stress-induced post-weaning diarrhoea in piglets.