How mycotoxins aggravate coccidiosis in poultry

Mycotoxins occur frequently in common poultry feed ingredients and can make birds more susceptible to coccidiosis by suppressing immune function.

This article appears in the December issue of Poultry International. View all of the articles in the digital edition of this magazine.

Coccidiosis is estimated to cost the poultry industry $3 billion annually, and is also a well-known predisposing factor for necrotic enteritis, which is widespread in broilers and responsible for losses of $2 billion worldwide each year.

Mycotoxins in feeds, even at permitted levels, aggravate coccidiosis in poultry. They can facilitate Eimeria colonization in the gut, and poultry producers looking to reduce the effects of coccidiosis on their flocks would do well to monitor feed for contamination

Gate openers to infection

Further research is required to fully understand the underlying mechanism that results in mycotoxins’ amplification of coccidiosis. However, possible explanations include increased immunosuppressive effects on modern high-performing broilers, chronic low-level mycotoxin exposure, and the potential for synergistic effects between mycotoxins.

Deoxynivalenol and fumonisins are known to interfere with several vital functions of cells, and disrupt intestinal cells that act as a barrier between pathogens and the birds’ bodies. These disrupted intestinal cell components can be used as a growth substrate for pathogens such as Eimeria, clostridium and Escherischia coli.

In this way, these mycotoxins play a main role as "gate openers" favoring pathogen colonization throughout the host.

Unsafe at any level

Even at concentrations allowed under European and U.S. guidelines for mycotoxins (Table 1), deoxynivalenol, fumonisins and a combination of the two can worsen the incidence and severity of coccidiosis in challenged poultry, studies have shown.

Guidelines 1612 Pi1mycotoxins1

Caps for mycotoxin contamination do not necessarily protect birds from mycotoxins’ harmful effects.

Chickens fed mycotoxin-contaminated feed at levels well below regulatory guidelines in starter and grower diets (Table 2) displayed considerably higher lesion scores, higher numbers of oocysts in the jejunum and in excreta, and higher lymphocyte (white blood cell) counts.

Experimental Diet1612 P Imycotoxins2

DON and FUM, although often overlooked in poultry diets, can negatively affect birds even at levels within regulatory guidelines.

Lesion scoring in the cecum was 1.33 for the mycotoxin groups versus 0.42 for birds fed control diets (Figure 1). The number of oocysts found in the jejunum was three times higher for birds fed mycotoxins versus control. Similarly, the number of oocysts recorded in feces was 29 percent higher for the deoxynivalenol + fumonisins group and 46 percent higher for the fumonisins group.

Lesion Score 1612 P Imycotoxins3

Groups fed mycotoxins all had considerably higher lesion scoring than the control group.

Overlooked risk

While the poultry industry has a general awareness of the dangers linked to certain mycotoxins, the threat posed by deoxynivalenol and fumonisins has been largely overlooked.

Yet, these mycotoxins occur frequently in the most common poultry diet ingredients, including finished feed, maize, wheat and soybean meal. 

A recent mycotoxin survey has revealed that deoxynivalenol was detected in 61 percent of maize, 54 percent of wheat, 71 percent of finished feed and 61 percent of soybean meal samples analyzed. Fumonisins were detected in 80 percent of maize, 27 percent of wheat, 66 percent of finished feed and 40 percent of soybean meal samples.

The implication for poultry producers looking to limit the use of antibiotics is to adopt robust mycotoxin risk management in order to protect flocks.

Mycotoxin Survey 1612 P Imycotoxins4

Mycotoxin contamination of maize (7,350), wheat (394), finished feed (1,638), and soybean meal (298) samples analyzed January to July 2016.

Antibiotic free

For antibiotic-free feeding that does not permit the use of ionophores — a class of antibiotics used solely for the purpose of preventing coccidiosis — coccidiosis management must rely on non-antibiotic coccidiostats, live coccidiosis vaccines or, more likely, a rotation between the two.

Probiotics and phytogenic feed additives, with or without the use of coccidiostats or vaccines, can help alleviate the negative effects of coccidial infection, having been shown to reduce oocyst shedding, severity of intestinal lesions, and adverse effects on performance.

 

Top 6 global mycotoxin threats to poultry

www.WATTAgNet.com/articles/26496.html

Page 1 of 1576
Next Page