Continuous advances in the poultry industry have stimulated the use of alternative feeds in poultry diets, and in particular glycerine, given its availability via the increase in world production of biodiesel. Glycerol is the principal component of glycerine, and can be used as an energy source to replace e.g. corn. However, other residual compounds, such as methanol and high levels of sodium, limit its use in animal feeds in large quantities. Several studies have found that the nitrogen-corrected apparent metabolisable energy of glycerine (AMEn) varies significantly between broilers, laying hens and quail, due to different processing/extraction methods (via biodiesel production). However, an energetic availability of at least 85% has been verified. Knowledge of the main metabolic pathways of glycerol and other components of glycerine is important for future studies on this feed material and to determine its main limitations. Understanding the relationship between the quality of the glycerine and its role as a source of dietary energy will allow more precise inclusion of glycerine in the formulation of balanced diets, without negatively affecting the performance of poultry.

Glycerol and ichthammol (G & I) has been used for generations by otologists. However, there is a paucity of information on both its mode of action and its anti-bacterial properties. The aim of this paper was to ascertain firstly, what the most common organisms found in discharging ears were and secondly, what antibacterial activity G & I had against these organisms. All ear swabs from 1992–1994 in our unit were reviewed to ascertain the prevalence of the commonly isolated organisms. Fresh isolates of these organisms were collected and plated onto agar with wells of glycerol, ichthammol and a combination of both as used in clinical practice. The diameters of the zones of inhibition observed after incubation were measured in millimetres. Common isolates were: Pseudomonas aeruginosa, Staphylococcus aureus, Proteus mirabalis, Streptococcus pyogenes in descending order of frequency. Pure glycerol showed no significant zones of inhibition against any of the organisms tested. The average zones of inhibition for G & I and ichthammol alone were for Staphylococcus aureus 15 mm and 18 mm and for Streptococcus pyogenes: 16 mm and 23 mm. Ichthammol alone was significantly more effective than G & I (p<0.001). There was no significant activity against Proteus mirabalis and Pseudomonas aeruginosa. The therapeutic benefit of G & I is due in part to the inherent anti-bacterial activity of ichthammol against the Gram positive organisms as well as its anti-inflammatory action and the dehydrating effect of the glycerol.