Effect of growth promoters on monensin toxicity in broiler chicks¹

Abstract

1. An experiment was carried out with male broiler chicks to evaluate the combined effect of monensin (150 mg/kg) and the growth promoters (GPs) Zn bacitracin (BAC, 50 mg/kg), virginiamycin (VIR, 25 mg/kg) and avoparcin (AVO, 20 mg/kg) fed from 7 to 28 d of age on performance, utilisation of dietary nutrients, yield of defeathered eviscerated carcases (DEC) and size of various organs. The effect of the GPs in the monensin-unsupplemented diets fed up to 49 d of age on performance and carcase was also determined. 2. Monensin significantly (P < 0.05) depressed food intake, weight gain and food efficiency from 7 to 28 d of age. None of the GPs was able to counteract these effects. However, AVO slightly ameliorated them. AVO also significantly increased food intake and improved gain and food efficiency during 7 to 28, but not 28 to 49 or 7 to 49 d of age. VIR and BAC did not affect performance in either age period. 3. Monensin did not affect the utilisation of dietary dry matter, fat or energy, but it significantly decreased nitrogen utilisation. AVO improved nitrogen and fat utilisation and increased dietary AME(n) content. AME(n) was also increased by VIR. The utilisation of these nutrients was not affected by the interactions between monensin and the GPs. 4. Monensin did not affect yield of the DEC or the relative liver size at 31 d of age. It significantly increased the relative length of the small intestine (SI) and decreased its specific weight. AVO significantly increased yield at 31, but not at 53 d of age. BAC and VIR did not affect this variable. AVO and VIR, but not BAC, at both age periods reduced, at times significantly, the size, length and specific weight of the SI. 5. Our conclusions: BAC, VIR and AVO do not counteract the toxic effect of monensin. The effect of GPs in improving performance decreases and even disappears with age, while their effect in reducing the size of the SI is still evident in 49-d-old birds.

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

“…Both acute and chronic intoxication have been described, especially with maduramycin in cattle fed poultry litter (192). Ionophore intoxication is also well known in birds (18,26,28,179). Not all bird species are equally sensitive to the toxicity of ionophores.…”

The Nutritional Value of High-Oil Corn for Broiler Chicks

“…Relative retention (RR) of the nutrients was calculated as described previously (Bartov, 1994). Results were subjected to ANOVA (Snedecor and Cochran, 1967) and to Duncan's multiple range test (1955), at a level of significance of 5%.…”

“…Strains of corn containing up to 22% oil were developed by a breeding program for high-oil corn (Dudley and Lambert, 1992). The increased oil content due to (Bartov, 1994).…”

Veterinary pharmacovigilance. Part 3. Adverse effects of veterinary medicinal products in animals and on the environment

“…Cardiomyopathy and myopathies have been seen in other species with ionophore poisoning (Wilson, 1980;Hanrahan et al, 1981;Muylle et al, 1981;Pressman & Fahim, 1983;Anderson et al, 1984;Novilla, 1992). The toxicities of ionophores may be potentiated by other substances and notably by the antimicrobial drug tiamulin (Miller, 1981;Wanner, 1984;Miller et al, 1986;Mitema et al, 1988;Pott, 1990;Bartov, 1994;Wendt et al, 1997;Basaraba et al, 1999;Szucs et al, 2000).…”