What’s up with the broiler feed intake?

Dr. Eija Valkonen, Area Sales Manager

Have you observed a plateau in broiler flock’s feed intake? Low feed intake of a broiler flock may be a sign of latent illness and result from disturbance in the gut homeostasis. Typically farmers notice a slowing development of feed intake around the third and fourth week of life (15–28 days of age). This slow development of feed intake may quickly translate to poorer weight gain.

There are many conditions and factors that may cause the observed plateau or slower development in the feed intake. Pathogens such as viruses, bacteria, and parasites may cause lesions, changes in the gut morphology, and disruption of the tight junctions. Consequently inflammatory reactions are induced. It is also known that mycotoxins can cause epithelial lesions in the gut leading also to inflammation. In addition antinutritional factors in feeds induce inflammation in the gastrointestinal tract. Whatever the cause, inflammation always reduces voluntary feed intake.

Sufficient feed intake is essential to good broiler performance. Measures to enhance feed intake (or rather nutrient intake) will also enhance growth. A well performing flock eats well, and has a steadily – almost linearly – increasing feed intake during the first six weeks (Fig.1). Further, feed intake in well performing flock will also increase due to a higher bodyweight and consequently higher intake capacity of the birds, emphasizing the difference between the poor and the well performing flocks.

Any stressor, be it pathogens, antinutritive factors, toxins or environmental factors, can trigger a cascade of inflammatory reactions. Although inflammation is an essential part of the body’s innate immune defense, it paradoxically often causes collateral damage to tissues. One mechanism causing such damage is the activation of matrix metalloproteinase (MMP) enzymes that break down collagen and tight junction proteins. Collagen is found in all connective tissues, also in the gut, where it is an essential structural part of the gut integrity.

Inflammation in the intestines will also lead to poorer performance. The major reason for this is the diminished feed intake. Other factors are related to the reallocation of nutrients from production to immune reactions and include for example tissue protein degradation, synthesis of acute-phase proteins, and increase of body temperature. Most of these metabolic changes associated with inflammation are orchestrated by cytokines. Pro-inflammatory cytokines have a restricting effect on feed intake. Thus limiting the inflammation will stimulate feed intake, and consequently improve the production performance.

Broiler studies made in Ghent University and at Alimetrics Ltd. have shown that dietary resin acids have anti-inflammatory effects in the intestine. These effects manifest themselves as lower expression and activity of MMP enzymes and lower density of inflammatory T-cells in mucosal tissue. Progres® is the only resin acid containing feed ingredient in the market and based on these studies it may limit intestinal inflammation.

In broiler performance trials, higher feed intake has been observed in Progres® fed birds in comparison to the birds receiving control feed (Fig. 2). This was especially evident during the time period typically being the most challenging for gut health, from 15 to 28 days of age. The improvement of the feed intake seen in the trials translated to significantly improved body weight gain at the end of the trials. The observed differences in feed intake may be associated with differences in inflammatory reactions, and may be a sign of lower level of inflammation in Progres® fed birds.

As a summary: Sufficient feed intake is crucial to achieving good broiler performance. Inflammation always reduces voluntary feed intake. By limiting inflammation Progres® helps broiler flocks to sustain the desired feed intake and growth performance.