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Commonly used treatments of poultry feed, such as pelleting, expanding or extrusion increase the physical density of the feed and lead to increased feed intake, reduced time spent feeding, improved growth rate and improved feed to gain ratio. Subsequently, improved feed conversion and better performance can often be observed when feeding processed diets compared to mash. Other benefts of thermal treatment include the ease of handling the fnished product, improved hygienic status of the feed, and reduced anti-nutritional factors. Besides the mechanic forces of processing, feed is also exposed to heat and steam as conditioning procedures. The amount and duration of heat and moisture applied while processing feed can have a signifcant effect on the availability of crude protein, amino acids, starch, fat, vitamins and feed additives. The effectiveness of feed processing on nutrient digestibility is also determined by the ingredients and their thermolability. There is a tradeoff between the control of feed borne diseases and digestibility of nutrients. Treat ment conditions which reliably reduce harmful micro-organisms may have an adverse effect on digestibility and performance. Short time exposure of the feed to high temperature improves the hygienic status of the feed with limited impact on nutrient digestibility. |
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