Why Can the Same Functional Factor Work So Differently in Different Animals?

Reference
Early life programming in poultry: Recent insights and interventional approaches. Frontiers in Veterinary Science, 2023.
Factors influencing the development of gastrointestinal tract and nutrient transporters' function during embryonic life of chickens. Journal of Animal Physiology and Animal Nutrition, 2023.
Tang X, et al. Epidermal growth factor and intestinal barrier function. Mediators of Inflammation, 2016.

Statement

This article is a translated and condensed summary based on the above review article. The content has been reorganized for scientific communication and educational purposes and does not represent the complete views of the original publication. Readers are encouraged to consult the original article for comprehensive information.

In animal nutrition, one question keeps coming up: why does a functional ingredient work brilliantly in one trial, yet give very different results when the species or the production stage changes? It's tempting to conclude that "this factor simply doesn't work." But the reality is rarely that simple. A living system is not a formula where adding an ingredient automatically triggers a response. For a functional factor to take effect, it must first go through a complete process of recognition, signal transduction, and response.

The Lock-and-Key Analogy

At the heart of this process is the receptor. Think of the functional factor as a key and the receptor on the cell surface as the matching lock: the signal can only get in if the two fit. Take EGF (Epidermal Growth Factor) as an example. It must first find target cells that express EGFR (Epidermal Growth Factor Receptor) and bind to it. Only then can it activate downstream signaling pathways that influence cell proliferation, differentiation, and tissue repair.

•   Which animal is the target?
  
•   Do the target cells express the corresponding receptor?
  
•   Is the signaling pathway intact?
  
•   Does the animal actually need this kind of regulation at its current stage?

Why Different Species Respond Differently

This also explains why the same functional factor can perform very differently in pigs, poultry, and aquatic animals. Several factors shape the final outcome:

• Species differences in receptor structure
• Differences in tissue-specific expression levels
• Distinct immune system characteristics
• Different growth or physiological stages

For this reason, future development of functional factors should not stop at "finding an effective molecule." We need to understand where the molecule acts and through what mechanism, so that it can be applied in the right place and deliver real value.

Huade's Technical Perspective

"Why does the same ingredient perform differently in different scenarios?" is a question we often hear in real-world product applications. Our understanding is that a functional factor never works as an isolated molecule. Its effect depends on whether three things line up: the target animal, the target stage, and the target tissue.

That is why, when designing functional products, "which animal and which stage it is used for" is often just as important as "which ingredient is used." Discussing efficacy without considering the application context can easily lead to one-sided conclusions.