Dynamics of intestinal metabolites and morphology in response to necrotic enteritis challenge in broiler chickens

Despite the relatively small contribution to metabolizable energy that volatile fatty acids (VFAs) provide in chickens, these organic acids have been reported to play beneficial roles in the gastrointestinal tract (GIT) of birds, for example, inhibition of the growth of some pathogenic bacteria. However, information regarding the dynamics of these metabolites in the GIT of chickens is still scarce, especially under disease conditions such as necrotic enteritis (NE). Here, we investigated the dynamics of VFAs and lactic acid, and intestinal morphology in response to NE predisposing factors, that is, excessive dietary fishmeal and 'Eimeria' inoculation, and causative agent 'Clostridium' perfringens producing NetB toxin. The experiment was designed in a 2 x 2 x 2 factorial arrangement of treatments with or without: fishmeal feeding, 'Eimeria' inoculation and 'C. perfringens' challenge. The results showed that these factors significantly influenced composition and concentration of VFAs and lactic acids, pH and histomorphometry in one way or another. These changes may be important for the onset of NE or only the synergetic responses to micro environmental stress. 'Eimeria' appeared to be more important than fishmeal in predisposing birds to NE, thus the application of 'Eimeria' in NE challenge provides more consistent success in inducing the disease. The metabolic responses to various adverse factors such as excessive dietary fishmeal and 'Eimeria' infection are complex. Thus, intensive efforts are required to better understand NE so as to achieve the control of the disease in the absence of antibiotics.