Effects on health, performance, and tissue residues of the ionophore antibiotic salinomycin in finishing broilers (21 to 38 d).

A study was conducted to evaluate the effects of feeding salinomycin at the recommended prophylactic level, and at 2 and 3 times this level, to finishing male broilers (d 21 to 38). Four treatment groups were given the experimental diets containing 0, 60, 120, or 180 parts per million (ppm) salinomycin from d 21 to 38. Performance, relative organ weights, selected serum enzymes, and salinomycin residues in liver, muscle, and serum were determined. Salinomycin supplementation had no effect on body weight, feed intake, or feed conversion, and caused no overt signs of toxicity. After a week of being fed the salinomycin diets, the serum activity of aspartate aminotransferase was significantly increased in chickens fed 180 ppm compared with controls. These birds also showed microscopic lesions in breast and thigh muscles, but not in cardiac muscle. Salinomycin residues were not detected by high-performance liquid chromatography coupled to tandem mass spectrometry in liver or muscle samples from the birds fed 0, 60, or 120 ppm salinomycin. However, chickens fed 180 ppm salinomycin had detectable levels in liver and muscle above the maximum residue level of 5 µg/kg established by the European Union. All birds fed salinomycin had salinomycin in their sera with levels ranging from N.D. (not detected) in the controls to 24.4 ± 7.9, 61.4 ± 18.9, and 94.5 ± 9.1 µg/L for salinomycin dietary levels of 60, 120, and 180 ppm, respectively. Serum salinomycin concentration was linearly related with salinomycin content in feed (y = 0.584x - 10, r2 = 0.999). The results showed that even at 3 times the prophylactic level, salinomycin does not induce clinical toxicosis or mortality. No salinomycin residues were found in edible tissues at the recommended dietary level or at 2 times this level. However, salinomycin was detected in serum regardless of the dietary level. A simple method for salinomycin determination in serum is described which can be used as a marker of exposure and/or to predict levels in the diet.

Effects of dietary Crotalaria pallida seeds on the health and performance of laying hens and evaluation of residues in eggs.

The effect of three dietary concentrations of Crotalaria pallida (C. pallida) seeds (0, 1, 2, and 3% w/w) of their normal diet were investigated in commercial laying hens during a 35 day feeding trial. All concentrations of C. pallida decreased body weight and feed intake (P < 0.05). Egg mass production and average egg weight were decreased by feeding of ≥ 2% C. pallida seeds (P < 0.05). All concentrations of C. pallida increased relative lung weight and serum activity of ALT, AST and LDH (P < 0.05); 3% C. pallida seeds decreased liver weight (P < 0.05). Analysis of the C. pallida seeds for dehydropyrrolizidine alkaloid content detected usaramine and its N-oxide at a total alkaloid concentration of 0.18% (dry weight). Usaramine was also detected in the eggs of all hens fed C. pallida seeds.

Evaluation of a method using high performance liquid chromatography with ultraviolet detection for the determination of statins in macromycetes of the genus Pleurotus cultivated by fermentation processes.

The applicability of high-performance liquid chromatography with ultraviolet light (HPLC-UV) for the determination of the presence of statins in macromycetes of the genus Pleurotus was analyzed. The fungi were obtained by liquid-state fermentation (LSF) using unconventional sources of carbon as substrates and solid-state fermentation (SSF) employing agro industrial wastes. Five statins were used as standards: lovastatin and simvastatin in the lactone form (LOVL and SIML), their corresponding hydro-acidic forms (LOVH and SIMH) and pravastatin (PRA). The following measures were evaluated: the linearity, accuracy and precision, detection limit (DL) and quantification limit (QL). The results demonstrated HPLC-UV to be an effective tool for detecting the presence of statins in extracts of LSF and SSF products. Likewise, it was hypothesized that the strains that were used for the study do not produce statins. This finding highlights the importance of continuing to evaluate other strains of the same genus by using techniques such as HPLC to first separate sufficient quantities of the compounds that were detected using the standard technique but that did not match the retention time (tR) of any of the standards used.