Escherichia coli (E. coli) is part of the normal intestinal flora of birds. Despite this, there are some virulent strains (APEC) capable of causing disease in broilers, turkeys and other bird species.

The disease outcomes due to environmental factors, secondary diseases and immunosuppression states. Aerosaculitis, polyserositis and septicemia are among the most characteristic symptoms worth noting. Diagnosis is based on clinical symptoms, injuries and isolation of E. coli.

It is a worldwide disease that causes huge economical losses around the world.

Pronutrients are active molecules from a natural origin, obtained from plant extracts, that improve animal physiology without causing a pharmacological effect. Immunostimulant pronutrients improve the immune response and boost the specific immune response after vaccination.

Objective

Check the effect of immunostimulant pronutrients in broilers challenged with E. coli during the last phase of fattening, as well as their capacity to replace antibiotics in this last phase.

Material and methods

The trial was carried out at the University Rovira i Virgili, Spain. There were 35-day-old broilers vaccinated against Newcastle and Gumboro diseases. The assay was 14 days long. There were four experimental groups:

• Group A: negative control group, without infection nor treatment.
• Group B: positive control group, challenged with 5000 CFU of coli per broiler
• Group C: pronutrient group, challenged with 5000 CFU of coli per broiler fed 0.5 kg of immunostimulant pronutrients per ton of feed.
• Group D: antibiotics group, challenged with 5000 CFU of coli per broiler fed 400 mg of sulfadiazine and 80 mg of trimethoprim per kg of feed.

Results

The final weight obtained was 1683.91 g in pronutrients group and 1673.15 g in the group treated with antibiotics, being the former the one with the best final weight and weight gain.

Feed conversion rate was slightly lower in the group treated with antibiotics.

In relation to mortality, the group treated with immunostimulant pronutrients had the fewest deaths, obtaining a rate even lower than the negative group. The group with the best efficiency index was the one treated with immunostimulant pronutrients.

Conclusion

Immunostimulant pronutrients significantly reduce mortality after an E. coli challenge during the last phase of broiler fattening.

The addition of this active molecules from a botanical origin enables, at the same time, to replace antibiotics during this last phase of production and to obtain greater growth and lower mortality rates.

Immunostimulant pronutrients are marketed under the name of Alquernat Immuplus, by Biovet S.A.

Picture: Low-temperature electron micrograph of a cluster of E. coli bacteria, magnified 10,000 times – Eric Erbe y Christopher Pooley, USDA