Batch variability of bacitracin: HPLC versus MEKC.

10 lots of bacitracin collected from the European market were studied applying the European Pharmacopoeia HPLC method, and the results were compared to the findings of an orthogonal micellar electrokinetic chromatographic method. The latter method exhibited a far higher selectivity, resulting in a baseline separation of all bacitracin components, which could not be achieved with HPLC. Considering the contents of bacitracin A, B1, and B3, the lots could be organised into 2 groups. Due to high amounts of bacitracin B1 and B3, one lot did not fit into either group. All lots met the requirements of the European Pharmacopoeia.

The bioefficacy of zinc bacitracin in practical diets for broilers and laying hens.

Two balance trials were conducted to examine the response in metabolizable energy and metabolizability of both fat and amino acids to graded levels of zinc bacitracin (ZnB; Albac registered trade name of Alpharma, Oslo, Norway) in practical broiler and layer diets varying in their nutrient density. Broiler diets were supplemented with either 0, 20, or 50 mg ZnB/kg and layer diets were supplemented with either 0, 50, or 100 mg ZnB/kg. Each experimental diet was fed to five replicates of four broiler chicks each or nine replicates of individually housed laying hens, respectively. All balance parameters were significantly influenced by nutrient density, age, and dietary ZnB level. No significant interactions between ZnB by nutrient density were found. Addition of ZnB resulted in a lower excreta:feed ratio and an improved N retention; there was a nearly linear relationship between these effects and dietary ZnB levels. Moreover, dietary MEn content was linearly enhanced by ZnB supplementation. As a consequence, the bioefficacy of ZnB can be expressed in terms of MEn units: the average MEn equivalency of ZnB was 2,080 and 1,184 Mcal/kg, for broiler chicks and laying hens, respectively.