PoultryUSA - March 2018 - 43
"Gut Health" in Animal Nutrition: What Are We Talking About?
Pietro Celi | DSM Nutritional Products | Columbia, MD
While gut health is an increasingly important and popular topic
in animal nutrition, a clear scientific definition is still lacking.
A definition of gastrointestinal functionality is needed to evaluate
the effects of nutritional interventions on both animal health
We propose the definition of gastrointestinal functionality as
"a steady state where the microbiome and the intestinal tract exist
in symbiotic equilibrium and where the welfare and performance
of the animal is not constrained by intestinal dysfunction." This
definition combines the principal components of gastrointestinal
functionality - namely diet, effective structure and function of
the gastrointestinal barrier, and normal and stable microbiota
- with effective digestion and absorption of feed and optimal
immune status (Figure 1). These components play a critical
role in gastrointestinal physiology, animal health, welfare
The intestinal microbiota contributes to the regulation of host
homeostasis by contributing to optimal digestion and absorption,
regulation of energy metabolism, prevention of mucosal infections
and modulation of the immune system. Consequently, dietary
manipulation of the composition of gastrointestinal microbiota
represents an attractive tool to promote animal performance.
Nutritional interventions should be designed to promote
conditions in the gastrointestinal tract that create and maintain
a balance between the host and the microbiota, as well as
prevent disturbance of the structure and function of the
The gastrointestinal mucosal epithelium and the gut associated
lymphoid tissue (GALT) are the first sites in the host exposed to
variations in nutrient intake. While relatively little is known about
how nutrients can alter development and function of the GALT,
it has been observed that diet can modulate its development.
Nutrient intake and microbiota colonization promote GALT
development. This occurs in parallel with the development
of the gastrointestinal tract, resulting in a functional immune
system. The GALT promotes gastrointestinal functionality by
differentiating between non-pathogenic and pathogenic antigens
and feed-borne threats to the host. This homeostatic orientation is
continuously challenged by physiological events and accelerated
productive performance which can result in a disregulation of the
tract's immune response.
When animals are challenged by harsh environmental conditions,
poor hygiene, high stocking rates or physiological stages of their
productive life, it is critical to ensure that nutrient supply not only
meets their requirements, but also maximizes GALT function
to maintain optimal animal welfare. Functional ingredients can
improve animal performance while maintaining health and
welfare. Optimal gastrointestinal functionality is crucial because
it improves feed efficiency, reduces use of antibiotics, and sustains
food safety, ultimately promoting sustainable animal production.
Figure 1. Main
components contributing to
Effective Immune Status
Effective Digestion and Absorption
In our opinion, a better insight in the evaluation and the progression
of several gastrointestinal conditions associated with nutritional
interventions that optimize gastrointestinal functionality needs to
be made a priority by the scientific community. This knowledge
can translate to practical applications that animal scientists and
feed formulators can utilize to further the health and welfare
Diet composition can influence the development and function of
the digestive system, immune system and microbiota. The use of
functional ingredients not only sustains animal health, welfare
and production, but also supports the immune system, modulates
redox balance and impacts the inflammatory response. Therefore,
functional properties of feed ingredients and additives related to
gastrointestinal health need to play a more central part in diet
formulation, as they can help maintain optimal animal health and
reduce the use of antibiotics.
Improved gastrointestinal functionality is often accompanied
by improved digestion and absorption. One might pose the
question of whether this is a direct cause or a consequence of
the observed improvement of gastrointestinal functionality. We
need to consider that intestinal inflammation negatively impacts
gastrointestinal function, since an increase in defensive responses
is often accompanied by a decrease in digestive efficiency with
reduced absorption of both macro and micronutrients.
Diets that do not provide adequate amounts of essential
nutrients will immune-compromise the animal. It has been
proposed that the host and microbiota form a 'superorganism'
and that the immune system is not a killer, but a force that
shapes homeostasis in the superorganism. The establishment
and maintenance of homeostasis is dependent on many factors.
This brings further support to our multidisciplinary definition
of gastrointestinal functionality that combines gut physiology,
endocrinology, microbiology, immunology and nutrition.
References available on request.
Sponsored content by DSM Nutritional Products