It is not fully understood how the consumption of microbials and probiotics can change energy use and immune function. And the authors said the findings may change producers’ minds on whether or not they move away from the sub-therapeutic use of antibiotics.
Co-author of the study Matthew Koci explained that microbials are not a direct replacement for the sub-therapeutic antibiotics but an “opportunity through a different mechanism”.
The study consisted of nearly 200 one-day-old broiler chicks, which were given different diets. One diet was a “standard control starter diet” and the second was a control starter diet with direct-fed microbials. Researchers then injected 12 chickens from each group with sheep red blood cells at seven days old as well as at 14 and 21 days.
The presence of the cells did challenge the immune systems of the chicks, but without causing illness and Koci said: “We wanted to give the immune system something to respond to and didn’t want to change the metabolism with a disease.”
Several parameters in the body were measured throughout the tests, including body weight, whole body expenditure, tissue respiration rates and energy metabolism. And over the 28-day period the tests were conducted, researchers found no difference in body weight or feed efficiency between the broilers on the two diets.
However, Koci explained that there could have been something “going on behind the scenes”. He said the interaction between direct-fed microbial species and intestinal cells can result in a change of energy consumption in the small intestine. The change in energy could lead to an increase in the amount of energy available to the immune system, he added.
The broilers on the microbial diet did have a faster response in their immune system. However, Koci pointed out that this was not a better response.
Findings from the study have led researchers to look at which mechanism or microbial is directly responsible for immune reactions. Koci said: “We hope to look at the physiological effects and trace them back to the signalling pathway.”
