Nov 17,2021
The environmental conditions in
which animal species are raised to increase productivity are far from optimal.
There has been a lot of interest in the role of animal nutrition in managing
the immune systems in order to enhance productivity. This concept becomes more
crucial in the production of animals without growth promoting antibiotics.
The necessity to combat anti-microbial
resistantbacteria is an issue of high priority for public health and
agriculture globally. It is possible to derive preventive and even curative
solutions from diets.
The immune response is an
essential defense mechanism of an animal. There are two types of immune
response which are identified as (a) Innate immune response and (b) Adaptive
immune response.
The innate immune response is a
non-specificresponse that occurs very rapidly leading to an inflammatory
process (Oswald, 2013). It is intended toexclude or eliminate pathogens
(Korver, 2012).
The body has many lines of
defense such as the skin and mucosal surfaces. Epithelial cells are the primary
barrier against the infectious and non-infectious challenges (Korver, 2012).
If these protective systems fail,
then pathogen-associated molecular pattern (PAMP) are recognizedby the system
through toll-like receptors (TLR) andpattern recognition receptors (PRR)
(Kogut, 2009).The early responses are directed towards containmentof the
pathogens. Various activation cascades finallylead to inflammation and
clearance of the pathogens(Kogut, 2009).
This innate response does not
exhibit memory unlikethe adaptive immune response.
This inflammatory response can be
costly from a nutritional standpoint. It can lead to a diversion of nutrient
away from growth and towards the inflammatory response. It also increases the
metabolic rate (fever) and/or reduces the feed intake. It also generates an
activity of the liver to produce the so-called Acute Phase Proteins which are
there to protectthe host against microbial growth. Morbidity, anorexiaand fever
can also be observed in such situations
1.1.2 Adaptive immunity
This component of the immunity
involves a specific response following an exposure to an antigen. Lymphocytes B
will produce antibodies to this antigenand T cells will actively eliminate
invading pathogens.The so-called T Helpers cells are here to direct the immune
response (Korver, 2009).
Adaptative immunity is activated
more slowly and is dependent on the innate immune system for initial pathogen
recognition. Expansion of B cells and T cellsare driven by the first signals
launched by the innate system with the specificity for the ongoing challenge (Kogut,2017).
The production of “memory” B
cells and T cells will provide lifelong specific protection.
The genetic selection of animals
for rapid growth has changed the way in which they respond to infectious
challenge. Modem broilers, for instance, appear to have lesser innate immune
response (less fever after a challenge). Their genetic makeup allows them to
grow rapidly with low feed conversion rate by minimizing the diversion of
nutrients to inflammatory response andother systemic response.
Modern commercial bred turkeys
are more susceptible to disease challenge than the wild-typeturkeys (Genovese
et al., 2008 quoted by Korver, 2012)
The selection for production
performance characteristics tend to result in decreased immunefunction
A network of interactions characterize
theinterdependence between the innate immune systemand the microbiota. The two
systems affect oneanother to bring about whole-organism physiology(Thaiss,
2016)
The gastrointestinal tract is the
primary site ofinteraction between the host immune system andModern
commercially bred turkeys are more microorganisms, both symbiotic and
pathogenic
Recent evidences support the idea
that disturbancesin the bacterial microbiota result in
Immunologicaldysregulation as inflammatory disease (Round andMazmanian, 2009)
Germ-free animals have numerous
immunologicaldefects that may lead to disease, which implies there isa role for
the microbiota in actively supporting health. The adaptive immune system is
influenced by intestinal microbial colonization.
The microbiotia, as a
"second brain" is a regulator of the immune response (Kogut, 2017).
The composition of the gut
microbiome is affected by variations in the diet and feed supplement in animals.
Therefore, diets and commensalmicrobiota have an influence on the host
immuneresponse.
In animal nutrition some
constituents of common diet can induce immune response. Insoluble Mannans are
not digestible by the poultry and are found to stimulate innate response in feed
supplement.
The presence of this Non Starch
Polysaccharides(NSP) can eventually lead to a demand for extra energy and
protein. The usage of exogenous enzymessuch as Beta-glucanase, Xylanase,
Protease andHemicellulase is appropriate and effective.
in animal nutrition many
nutrients in the feed supplements are capable of modulating the immune system
Immune functions are influenced by diet composition, feed, feed supplement and
energy intake. Deficiencies of nutrients in feed supplement, such as protein,
lysine, arginine and phosphorus can reduce immune response
During the acute phase of an
inflammation a large part of the protein synthesis is dedicated to the
production of acute phase protein. (Reeds and Jahoor (2001) evaluated that it
could represent upto 25% of the total synthesis. Preferential breakdown of skeletal
muscle supports energy demand. In fact, the profile of these acute phase
proteins is different from those of the muscle. Consequently, during stress,
birds will have specific requirements as far as amino acids areconcerned.
Tryptophan and Arginine levels in
the diets can modulate the systemic immune response against Gumboro disease
(Emadi et al., 2011). It is also true forthe sulfur amino-acid (Jankowski,
2014) and threonine (Amadori et al., 2009)
As a result challenged birds will
have a different protein demand in their feed supplement as opposed to
non-challenged birds.
To clear the pathogens invasion,
some of the host cellsproduce pro-oxidant elements. An inflammatorycondition
can impair the balance between thisproduction and the anti-oxidant status of
the tissuesand cause an oxidative stress. Feed supplement with antioxidants in
such situations becomes important.
The challenge that a nutritionist
faces is to choose amongst various raw materials and feed additives that are
required as per the nutrient specifications of various animal species and animal
nutrition. Addition of more than what is required in the feed supplement does
not bring about a corresponding benefit.
Following is the review of important
feed supplement
Essential oils (EO) are widely
used as alternative to antibiotic growth promoter in animal feed supplement.
They are known for their anti-bacterial properties, and like antibiotics, EO
also shows anti-inflammatory and anti-oxidant properties, enhancing the quality
of animal feed supplement. Many studies demonstrate the immunomodulatory
effects of natural and herbal products (Lillehoj and Lee, 2012)
Dietary feed supplement like
cinnamaldehyde along with carvacrol and capsicum showed synergistic enhancement
of innate immunity against intestinal parasitic and bacterial infections.
Probiotics are "live
microorganisms that can influence the profile of the microbiota, enhance feed quality,
modulate the inflammatory response and improve the non-specific intestinal
barrier" (Lillehoj and Lee, 2012).
The live microorganisms that are
commonly included in feed supplement are Bacillus, Bifidobacterium,
Enterococcus, Lactobacillus, Lactococcus, Streptococcus, Saccharomyces
cerevisiae and Aspergillus oryzae. Many studies demonstrate the role of such feed
supplements in immunomodulation.
Bacillus subtilis is one of the
most common feed additives used in animal nutrition as the spores of B.
subtilis are heat resistant and can tolerate multiple environmental stressors.
Feeds supplement with Bacillus
subtilis-based probiotic reduces heat stress-related behaviors and inflammatory
response in broiler chickens (Wang. 2018)
Omega-3 polyunsaturated fatty
acids are well recognized to reduce the growth-suppressive impacts of
inflammation (Korver, 1998). From a metabolic standpoint, Omega 3 PUFA is good
for the immune system.
Eicosapentaenoic Acid (EPA),
docosahexaenoic Acid (DHA) and a-linolenic Acid (ALA) are also beneficial for
the immune system
The chain length is important.
The longer the chain, the better is the immunity.
The use of oils enriched in PUFA
is certainly an option that a nutritionist needs to consider as feed supplement
for animal species under challenging conditions.
Animal nutrition can vastly
effectthe immune stimulation following a vaccination. In a trial, Broilers were
fed with feed supplement with a phytogenic solution (Techna, non-published
data, 2007). Post vaccination, antibodies titer was monitored. Serocon version
was boosted for Gumboro, Infectious Bronchitis and Newcastle valences for
birds.
The immune system of an animal is
highly complex and a robust immune system is the key to optimal health and
performance.
The immune-animal nutrition
approach is a proven strategy to improve immunity. However, this subject still
requires a lot of research to identify all the links between animal Nutrition,
Pathology and Immunity. There definitely exists a cost for immunity and feed
supplement which affects performance parameters of animals.
A better comprehension of how animal feed
supplements modulate the immune response gives nutritionists the ability to
formulate diets to improve animal nutrition, immunity and overall health.