Antibiotic Potentiation

On the Inhibition of Tetracycline Absorption by Dietary Calcium

“…Also of interest is the observation that replacement of the calcium chloride by calcium sulfate is not so effective in preventing the TC precipitation as the lowering of the calcium concentration. This is again in complete agreement with parallel feeding trials in which various calcium levels were fed and in those where calcium sulfate replaced calcium carbonate (Donovan et al, 1962).…”

“…Quantitatively, this mechanism is sufficient to account for the inhibition observed by various investigators in feeding trials and subsequent blood analysis of TC (Price et al, 1959). Additional evidence may be provided by the observation that less precipitation occurred with CaS0 4 than with CaCl 2 , which may explain the potentiating effect of calcium sulfate (Donovan et al, 1962;Nelson et al, 1964). Also of interest is the observation that replacement of the calcium chloride by calcium sulfate is not so effective in preventing the TC precipitation as the lowering of the calcium concentration.…”

“…Improvement of the antibiotic absorption could be obtained by reducing the level of dietary calcium (Price et al, 1959), by replacing the calcium carbonate supplement with calcium sulfate (Donovan et al, 1962) or by supplementing the diet with sodium sulfate (Nelson et al, 1964). ; On the basis of some of these findings it was theorized that the calcium ion directly inhibits biological action and intestinal abi sorption of tetracycline and related com-, pounds.…”

“…; On the basis of some of these findings it was theorized that the calcium ion directly inhibits biological action and intestinal abi sorption of tetracycline and related com-, pounds. It has also been stated that calcium sulfate, or supplementation with so-; dium sulfate, which would form calcium , sulfate with the soluble calcium, may serve : as an antibiotic potentiator due to the L lower rate of release of calcium ions from t this salt (Donovan et al, 1962).…”

Potentiation of Chlortetracycline in Laying Chickens

“…The hens fed calcium sulphate showed diarrhoea, egg production declined and had almost stopped by the end of the test period and a marked decline in specific gravity of eggs was noted. Donovan et al (1962) noted that use of calcium sulphate increased litter moisture by 33 percent.…”