One of the main issues in poultry husbandry is efficient and sustainable animal production. Several factors such as raw material prices and increasing worldwide competition force farmers to optimize their production cycles. Moreover, farmers have to deal with animal welfare regulation, restriction of antibiotic usage and prevalence of infectious diseases. When animals are subject to stress factors such as animal density, climate condition, type of housing or change of feed, they are highly susceptible to infectious diseases and (metabolic) disorders.
These diseases can be caused by gram-negative pathogenic bacteria like E.coli and Salmonella, or by gram-positive pathogenic bacteria like Streptococci and Staphylococci. Also viral infections such as IB or ND can cause a variety of diseases weakening the animal. Antibiotics and vaccination programs are commonly used, however, not all bacteria and viruses can be targeted due to economic and/or practical disadvantages.
Infection by bacteria and viruses may lead to decreased growth and reproduction performance, high mortality rates and lower profitability. Moreover, especially in young animals, stress factors may lead to an underdeveloped intestinal tract, resulting in decreased immunity and digestion.