POULTRY MANURE BIOVALORIZATION PROCESS

The huge production of poultry wastes led to intensive research in the field of waste recycling and bioengineering aspects of this solid-waste treatment. In the recent years, poultry manure has been used, directly or after transformation by chemical (acidification) or physical (heating) processes, in feed formulations. The treated material was used in low concentrations in feeds. However, the use of biotechnological processes in the field of waste recycling and transformation can be a good way to ensure the safety of the obtained product, which are now qualified as «bio-products ».
Many tentatives to develop suitable methods for the treatment of poultry waste were described. Chemical acidification by acetic acid, propionic acid or a mixture of both was also used to eliminate pathogens and formaldehyde was also tried for reducing the undesirable microorganisms. Several papers have been given on the biological fermentation or ensilage of poultry manure. However, none of these methods used a controlled fermentation by pure cultures of lactic acid bacteria.
Poultry wastes include the excreta of poultry and parts of feed and other subsequent materials such as feathers and beeding. These materials are produced in high amounts through out the world and would constitute a cheaper source of proteins for the developing countries if appropriately transformed and/or preserved. Several methods and procedures were applied to preserve and to transform these wastes into usable materials in feeds or as substrates for the production of organic fertilizers.

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1 Crude poultry waste             2 Biotransformed poultry manure

The need for animal feeds is increasing more and more due to the animal and poultry growing increase. The agricultural crops to be used in animal feeds are in shortness. So, to balance the lack of protein sources, a part of animal wastes can be used at least partly in feed formulation. The usual techniques including drying and/or chemical treatments (formol, acidifying etc..) are not safer and can induce other problems to the animals and/or to the consumer
New techniques using biotechnological processes are more interesting for the control of food and feed systems. Not only are these wastes preserved but they are also transformed into a new ingredient. The use of lactic acid bacteria would have a natural inhibiting activity on the undesirable microflora in wastes which would result in a natural preservation and the biotransformation technology can be monitored in such a way that the ingredient is safer.
Poultry wastes (manure), collected from different poultry farms were first characterized microbiologicaly by standard plate count and counts of coliforms, Clostridium, enterococci and Salmonella. Procedures for inhibiting the undesirable microorganisms by a biological process was carried out by the use of lactic acid fermentation. The strains used belong to Lactobacillus plantarum and Pediococcus sp which were inoculated to diluted poultry wastes. The wastes (caged laying hen excreta) were diluted by adding the same amount of distilled water (1:1) and inoculated with a 5 % (v/v) of a 48 hours starter culture. The different microbial groups were followed for 15 days.
Results indicated that the wastes were highly contaminated with hazardous microorganisms. Coliform counts ranged from 5x106 to 6x108 cfu/g, enterococci counts were also high and reached 2.4x108 cfu/g, Clostridium levels were around 80 -200 cfu/g and the standard plate count varied between 8107 and 4109. All these microbial populations were drastically reduced by the fermentation process. The pH was decreased to 4.01 and the growth curve of the starter culture (lactic acid bacteria) showed a typical pattern for a successful growth. The total volatile nitrogen was also decreased to lower values (0.1 %) in the fermented product.

Different feed formulas for poultry made from poultry manure