Outbreaks of necrotic enteritis are sporadic and may result in high mortality and severe economic losses. It has been estimated that the cost of sub-clinical necrotic enteritis can be as much as Rs. 2/- per bird.
Animal proteins are favourable substrates for Clostridial growth, and high concentrations in broiler feeds are often associated with NE. Fishmeal exacerbates NE. There is a positive association between crude protein derived from fishmeal and numbers of ilea and caecal C. perfringens. Increased gizzard pH, stimulated by animal protein, encourages C. perfringens proliferation. Animal fat (lard or tallow) may lead to higher ilea counts of C. perfringens than vegetable oil does.
Relatively high zinc concentrations occur in wheat, meat-meal and fishmeal, all of which are predisposing factors to NE.
Alkaline pH may be a predisposing factor because C. perfringens growth in vitro is inhibited at low pH and toxin production is increased at high pH.
Cereals containing large amounts of Non Starch Polysaccharides (NSPs) increase digesta viscosity, which increases the gut passage time. This in turn may allow anaerobic bacteria to proliferate and produce enterotoxins.
In today's scenario of narrow margin, high volume broiler and layer business, the disease determinants associated with the production environment are the ones which ultimately decide the turning point of the flocks' performance. Flock health, more specifically gut health, remains the most important contributor to optimal performance.
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Article made possible through the contribution of Biomin.