ABSTRACT
The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4''-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4''-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Dysentery/veterinary , Leucomycins/therapeutic use , Swine Diseases/prevention & control , Treponemal Infections/veterinary , Tylosin/analogs & derivatives , Animals , Carbadox/therapeutic use , Dysentery/drug therapy , Dysentery/prevention & control , Leucomycins/pharmacology , Microbial Sensitivity Tests , Swine , Swine Diseases/drug therapy , Treponema/drug effects , Treponemal Infections/drug therapy , Treponemal Infections/prevention & controlABSTRACT
The hypothesis was tested that vitamin E protects chickens from a lethal Escherichia coli infection by inhibiting the biosynthesis of prostaglandins, thereby activating humoral immunity and phagocytosis. When chickens were fed supplement vitamin E at the level of 300 mg/kg diet, which is six times the presently used dietary level, endogenous PGE1, PGE2, and PGF2 alpha levels decreased in the immunopoietic organs, bursa, and spleen. Antibody titers to E. coli lipopolysaccharide and phagocytosis increased at the same time. Infection slightly increased prostaglandin levels and vitamin E appeared to compensate for this increase. Aspirin, a known prostaglandin inhibitor acted synergistically with vitamin E in depressing endogenous PG levels in bursa and decreasing mortality from E. coli infection.
