In situ utilization of biogas on a poultry farm: Heating, drying and animal brooding

Biodegradation of keratin waste: Theory and practical aspects

Keratin-rich by-products, i.e. bristles, horns and hooves, chicken feathers and similar, are a source of nutrients for animals (amino acids) and plants (N, S). Contemporary developments in the management of keratin waste in feeds and fertilizers comply with human and animal health protection regulations and respect the principles of ecological development. Biotechnological methods employing keratinolytic bacteria and microscopic fungi play a key role in processing keratin waste. This study reviews the current knowledge on the ecology and physiology of keratinolytic microorganisms and presents the biodegradation mechanism of native keratin. The structure and chemical composition of keratin proteins are described, and methods of keratin waste biotransformation into products of practical industrial and natural value, especially composts, are discussed.

Effect of anaerobic digestion on oocysts of the protozoan Eimeria tenella

The effect of anaerobic digestion of poultry waste on oocysts of the protozoan Eimeria tenella, a common enteric pathogen that causes coccidiosis in poultry, was investigated in this study. Thermophilic (50 degrees C) and mesophilic (35 degrees C) anaerobic digestors, with poultry manure as the substrate, were inoculated with the oocysts. The oocysts were damaged during anaerobic digestion, as determined by morphological change and loss of their ability to sporulate. The recovered oocysts were tested for their infectivity in young chicks, as measured by body weight gain, mortality, and cecal lesions. Oocysts lost all their infectivity during thermophilic digestion, while oocysts subjected to mesophilic digestion remained moderately infective in comparison with untreated oocysts, which produced severe coccidiosis, high mortality, and low body weight gain in chicks. Oocysts were inactivated at 50 degrees C when they were suspended in digestor fluid or saline. Inactivation at 35 degrees C was significantly stronger in the digestor fluid than in the saline, which implied that factors other than temperature were involved in the lethal effect of anaerobic digestion on protozoan oocysts. In this study we demonstrated that the treatment of animal waste by anaerobic digestion, especially at a thermophilic temperature, has the benefits of pathogen control and protection of human and animal health in a farm environment.