**3. Factors influencing gut health**

#### **3.1 Nutrients in relation to gut development & Health**

In diet certain nutrients play a crucial role in metabolism, absorption as well as participate in maintain gut health and homeostasis. In diet ingredient quantity, quality, form, type, processing method, additive types..etc. play a dynamic role in maintain gut microbiota and integrity [20]. Some of the reports regarding application of nutrients more than recommendation and its impact on gut health was presented in **Table 1**.

#### *3.1.1 Carbohydrates*

Production of molecules involved in defecen mechanism like monocytes and heterophils, Ig, nitric oxide, lysozome, communication moluclues (eicosanoids, cytokines, and clonal proliferation of antigen-driven lymphocytes) are depending on availability of energy, amino acids, enzyme co factors etc. [20].

Energy from carbohydrate source is the best choice since immunological stress is known to impair triglyceride clearance from the blood, thus decreasing fat utilisation. Ingredients of plant origin contain considerable amounts of fibre (non-starch polysaccharides, NSP, plus lignin), with the majority being insoluble which has various roles in improving gut health, enhancing nutrient digestion and modulating the behaviour of animals. It is postulated that monogastric animals have a 'fibre requirement' because their gut development requires physical stimulation by hard, solid particles of feed [34].

#### *3.1.2 Proteins and amino acids*

Using dietary protein intake as an example, at elevated temperatures, digestion and absorption are altered, favouring protein catabolism, and subsequently a reduction in protein synthesis and deposition [35]. Kumari et al., [36] reported that low protein diets (17 vs.15.58 & 13.4%) for layers supplemented with ideal amino acid lysine @ 0.70% at high temperature (32°C) from 25 to 36 weeks of age is essential for better performance on par with 17% protein in diet. However, Temim et al. [37] reported that high protein diets (28 and 33%) improved the performance when compared to low protein diets (20%) in broiler chicks. Burkholder et al. [38] noticed that stress conditions either due to high temperatures or due to fasting for more than 24 hrs, changes in microbial population and increased attachment or colonisation of pathogenic bacteria like salmonella.

Role of some amino acids (Glutamine, Arginine, Threonine and Cysteine) on the integrity, growth, and development of the intestinal epithelium, gene expression, cell signalling, antioxidative responses, and their associated immune functions have been investigated by [39–42].

Digestion and absorption are influenced by gut health and villi length especially infections which damages the epithelia during such situation supplementation of amino acids favours the production of SCFAs which improves the immunity [43, 44].

#### *3.1.3 Minerals*

Research findings inferred that the role of trace minerals in maintaining the intestinal health supports anti oxidant system, balancing micro biota and repair. Shanon and Hill [45] reported importance of copper in growth and mechanism of gut, high concentration of Zn prevents proliferation of pathogenic (clsotridum and E.coli) bacteria.

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*Gut Health and Immunity in Improving Poultry Production*

**Strain/type application Biological activity Reference**

*L. acidophilus* Induced T-helper-1 cytokines

*L. salivarius* Induced anti-inflammatory

FOS Provided nutrients for the

Inulin Increased bifidobacterium

GOS Increased Bifidobacterium

Prebiotic-based MOS and b-glucan Increased the relative weight

IMO Increased the caecal

Lactobacillus and bifido bacter population is increased and E.coli counts are decreased in caeca.

in caecal tonsil cells

responses (interleukin [IL]-10 and transforming growth factor [TGF]-b) in caecal tonsil cells

Increased antibody titre against Newcastle disease (ND). Increased the geometric means haemagglutination inhibition (HI) titres of birds

Increase in intestinal villus height and crypt depth in the jejunum and ileum and goblet

cell number.

growth of beneficial bacteria in the gut

spp. and decreased Campylobacter spp. in the

faecal samples

the caecal E. coli

Increased serum concentration of IgA and IgM, and enhanced systemic immune capacity in chickens

enteritidis

intestine

faeces

Reduced C. jejuni concentration in poultry

of spleen, decreased the heterophil-to-lymphocyte ratio and increased antibody titres against S.

Increased the LAB population and reduced E. coli and total coliform populations in the

counts and decreased *E. coli* counts in caecal contents

populations of lactobacilli and bifidobacteria and decreased

Mookiah et al. [21]

Brisbin et al. [22]

Khan et al. [23]

Naga Raja Kumari and Susmita [24]

Alloui et al. [25]

Nabizadeh [26]

Baffoni et al., [27]

Mookiah et al. [21]

Sadeghi et al. [29]

Amerah et al. [30]

Baffoni et al., [27]

Vidanarachchi et al. [28]

*DOI: http://dx.doi.org/10.5772/intechopen.95989*

*L*.*reuteri, L.gallinarum, L .brevis, L* 

*L.plantarum,L.bulgaricus, L.acidophilus,L.rhamnosus, B.bifidum,S.thermophilus,E. faecium, A. oryzae and C. pintolopessi*

Fibregum and Raftifeed-

IPE

**Symbiotics**

product

Commercial synbiotics (BiominImbo)

Bifidobacterium-based symbiotic

*Saccharomyces boulardii*

**Prebiotics**

**Probiotics**

*.salivaris*


*Advances in Poultry Nutrition Research*

presented in **Table 1**.

*3.1.2 Proteins and amino acids*

been investigated by [39–42].

colonisation of pathogenic bacteria like salmonella.

*3.1.1 Carbohydrates*

**3. Factors influencing gut health**

**3.1 Nutrients in relation to gut development & Health**

In diet certain nutrients play a crucial role in metabolism, absorption as well as participate in maintain gut health and homeostasis. In diet ingredient quantity, quality, form, type, processing method, additive types..etc. play a dynamic role in maintain gut microbiota and integrity [20]. Some of the reports regarding application of nutrients more than recommendation and its impact on gut health was

Production of molecules involved in defecen mechanism like monocytes and heterophils, Ig, nitric oxide, lysozome, communication moluclues (eicosanoids, cytokines, and clonal proliferation of antigen-driven lymphocytes) are depending

Energy from carbohydrate source is the best choice since immunological stress is known to impair triglyceride clearance from the blood, thus decreasing fat utilisation. Ingredients of plant origin contain considerable amounts of fibre (non-starch polysaccharides, NSP, plus lignin), with the majority being insoluble which has various roles in improving gut health, enhancing nutrient digestion and modulating the behaviour of animals. It is postulated that monogastric animals have a 'fibre requirement' because their gut development requires physical stimulation by hard, solid particles of feed [34].

Using dietary protein intake as an example, at elevated temperatures, digestion and absorption are altered, favouring protein catabolism, and subsequently a reduction in protein synthesis and deposition [35]. Kumari et al., [36] reported that low protein diets (17 vs.15.58 & 13.4%) for layers supplemented with ideal amino acid lysine @ 0.70% at high temperature (32°C) from 25 to 36 weeks of age is essential for better performance on par with 17% protein in diet. However, Temim et al. [37] reported that high protein diets (28 and 33%) improved the performance when compared to low protein diets (20%) in broiler chicks. Burkholder et al. [38] noticed that stress conditions either due to high temperatures or due to fasting for more than 24 hrs, changes in microbial population and increased attachment or

Role of some amino acids (Glutamine, Arginine, Threonine and Cysteine) on the integrity, growth, and development of the intestinal epithelium, gene expression, cell signalling, antioxidative responses, and their associated immune functions have

Digestion and absorption are influenced by gut health and villi length especially infections which damages the epithelia during such situation supplementation of amino acids favours the production of SCFAs which improves the immunity [43, 44].

Research findings inferred that the role of trace minerals in maintaining the intestinal health supports anti oxidant system, balancing micro biota and repair. Shanon and Hill [45] reported importance of copper in growth and mechanism of gut, high concentration of Zn prevents proliferation of pathogenic (clsotridum and

on availability of energy, amino acids, enzyme co factors etc. [20].

**102**

*3.1.3 Minerals*

E.coli) bacteria.


#### **Table 1.**

*Results of some of the works in application of additives in poultry diets.*

Whereas, Baxter et al. [46] inferred that chelated minerals and EAA at optimum concentration in diet has great influence on gut health especially during heat stress.

Zn in the form of ZnO protects the intsetianal cell from E.Coli infestation, inhibits adhesion and internalisation of bacteria, prevents the commotion of barrier integrity, and modulates cytokine gene expression [47].

Several elements in diet have been shown to have a negative effect on the immunological response in the bird when they are deficient in the diet. Several studies revealed that adequate levels of Zn supplementation (between 50 and 70 mg/kg) in poultry diet have been shown to minimise the impact of oxidative damage in the intestine of broilers under stress [48, 49]. Zinc is especially important in wound healing, thymic function and proliferation of lymphocytes. Growth depression usually observed due to catabolic response during nutritional stress induced immune stimulation.

#### *3.1.4 Vitamins*

Vitamin E appears to be an immune system "booster" and by inhibiting the synthesis of prostaglandins [50].

Vitamin A deficiency [51, 52] and excess [52, 53] have been shown to depress immune responses in chicks. Most research suggests that vitamin A deficiency is associated with reduced cellular immune responses whereas; vitamin A excess impairs antibody responses.

To reduce stress in the form of vaccination/handling/environment boosting the diet with B vitamins, fat-soluble vitamins (A, D, and E), and electrolytes in drinking water are helpful in antibody production and also to reduce mortality from the stress [54].

**105**

*Gut Health and Immunity in Improving Poultry Production*

Feed microbials are used to colonies in the intestine with microbes of desirable attributes that can promote competitive exclusion and/or promote beneficial gut barrier and immune function. Choice of in feed eubiotic additives in diets have positive influence on intestinal microila community and to improve the birds

Commonly used probiotics species at poultry industry are LAB, i.e., *Lactobacillus* 

*Streptococcus thermophilus, Enterococcus faecium, E. faecalis, Bifidobacterium spp.,* [55, 58].

Prebiotics are non digestible feed ingredients acts as a substrates for microbes, can helps in shaping the gut microbiome and, in turn, developing the immune capabilities [57, 59]. Prebiotics provide nutrients for endogenous favourable bacteria like bifido acteris and LAB and improves host microbiota balance [57]. Oligosaccharides (inulin, fructooligosaccharides (FOS), mannanoligosaccharides (MOS), galactooligosaccharides (GOS), soya-oligosaccharides (SOS), xylooligosaccharides (XOS)) pyrodextrins, isomaltooligosaccharides (IMO) and

A combination of probiotic(s) and prebiotic(s), which attempts in providing

Alter the availability of nutrients from the substrates and increase the digesta viscosity. Poultry rations are mainly based on ingredients of palnt origin with more phytate phosphorus, to make use of P from the source phytase enzyme are normally used, apart from this proteases, NSPases are very common [61]. Various exogenous enzymes including b-glucanase, xylanase, amylase, a-galactosidase, protease, lipase, phytase, etc. have been supplemented in poultry diets for

Phytobiotics are the compounds (terpenoids, phenolics, glycosides and alkaloids

etc.) derived from the plants, which posses antimicrobial and some functional properties [59, 62]. Some of the phytobitics enhance the growth of useful bacteria like LAB in gut, improves immunity, protects intestinal cells by altering the mem-

Butyric acid, Lactic, acetic, tannic, fumaric, propionic, caprylic acids, etc. comes under this category, which had antimicrobial properties, enhance gut structure and alter pathogen gene expression and enhance the performance of

*bulgaricus, L.acidophilus, L.casei, L.helveticus, L.lactis, L.salivarius, L.plantarum,* 

lactulose..etc. [25, 59, 60] are commonly used prebiotice in poultry.

favourable microorganism(s) along with a nutrient source.

*DOI: http://dx.doi.org/10.5772/intechopen.95989*

*3.1.5 Probiotics*

*3.1.6 Prebiotics*

*3.1.7 Synbiotics*

*3.1.8 Exogenous enzymes*

decades [31, 32].

*3.1.9 Phytobiotics*

brane permeability [63, 64].

*3.1.10 Organic acids*

birds [65, 66].

immune system [55–57].

*Gut Health and Immunity in Improving Poultry Production DOI: http://dx.doi.org/10.5772/intechopen.95989*

### *3.1.5 Probiotics*

*Advances in Poultry Nutrition Research*

Synbiotic 11 Lactobacillus strains

plus IMO

**Exo genous enzymes**

Whereas, Baxter et al. [46] inferred that chelated minerals and EAA at optimum concentration in diet has great influence on gut health especially during heat stress. Zn in the form of ZnO protects the intsetianal cell from E.Coli infestation, inhibits adhesion and internalisation of bacteria, prevents the commotion of barrier

populations increased

**Strain/type application Biological activity Reference**

coli

Carbohydrase Increased the proportion

Xylanase Minimise the counts of

Exogenous enzymes change in the gut microbial

Xylanase Reduced crypt depth of

*Results of some of the works in application of additives in poultry diets.*

Increased the caecal populations of

of lactic and organic acids, reduced ammonia production, and increased VFA concentration through hydrolysis fragmentation of NSP and supporting growth of beneficial bacteria.

Salmonella

immunity

jejunum

lactobacilli and bifidobacteria and decreased the caecal E.

Mookiah et al. [21]

Adeola and Cowieson [31]

Amerah et al. [30]

Yang et al. [33]

Bedford and Cowieson [32]

Several elements in diet have been shown to have a negative effect on the immunological response in the bird when they are deficient in the diet. Several studies revealed that adequate levels of Zn supplementation (between 50 and 70 mg/kg) in poultry diet have been shown to minimise the impact of oxidative damage in the intestine of broilers under stress [48, 49]. Zinc is especially important in wound healing, thymic function and proliferation of lymphocytes. Growth depression usually observed due to catabolic response during nutritional stress induced immune

Vitamin E appears to be an immune system "booster" and by inhibiting the

Vitamin A deficiency [51, 52] and excess [52, 53] have been shown to depress immune responses in chicks. Most research suggests that vitamin A deficiency is associated with reduced cellular immune responses whereas; vitamin A excess

To reduce stress in the form of vaccination/handling/environment boosting the diet with B vitamins, fat-soluble vitamins (A, D, and E), and electrolytes in drinking water are helpful in antibody production and also to reduce mortality from the

integrity, and modulates cytokine gene expression [47].

**104**

stress [54].

stimulation.

**Table 1.**

*3.1.4 Vitamins*

synthesis of prostaglandins [50].

impairs antibody responses.

Feed microbials are used to colonies in the intestine with microbes of desirable attributes that can promote competitive exclusion and/or promote beneficial gut barrier and immune function. Choice of in feed eubiotic additives in diets have positive influence on intestinal microila community and to improve the birds immune system [55–57].

Commonly used probiotics species at poultry industry are LAB, i.e., *Lactobacillus bulgaricus, L.acidophilus, L.casei, L.helveticus, L.lactis, L.salivarius, L.plantarum, Streptococcus thermophilus, Enterococcus faecium, E. faecalis, Bifidobacterium spp.,* [55, 58].

### *3.1.6 Prebiotics*

Prebiotics are non digestible feed ingredients acts as a substrates for microbes, can helps in shaping the gut microbiome and, in turn, developing the immune capabilities [57, 59]. Prebiotics provide nutrients for endogenous favourable bacteria like bifido acteris and LAB and improves host microbiota balance [57]. Oligosaccharides (inulin, fructooligosaccharides (FOS), mannanoligosaccharides (MOS), galactooligosaccharides (GOS), soya-oligosaccharides (SOS), xylooligosaccharides (XOS)) pyrodextrins, isomaltooligosaccharides (IMO) and lactulose..etc. [25, 59, 60] are commonly used prebiotice in poultry.

#### *3.1.7 Synbiotics*

A combination of probiotic(s) and prebiotic(s), which attempts in providing favourable microorganism(s) along with a nutrient source.

#### *3.1.8 Exogenous enzymes*

Alter the availability of nutrients from the substrates and increase the digesta viscosity. Poultry rations are mainly based on ingredients of palnt origin with more phytate phosphorus, to make use of P from the source phytase enzyme are normally used, apart from this proteases, NSPases are very common [61]. Various exogenous enzymes including b-glucanase, xylanase, amylase, a-galactosidase, protease, lipase, phytase, etc. have been supplemented in poultry diets for decades [31, 32].

#### *3.1.9 Phytobiotics*

Phytobiotics are the compounds (terpenoids, phenolics, glycosides and alkaloids etc.) derived from the plants, which posses antimicrobial and some functional properties [59, 62]. Some of the phytobitics enhance the growth of useful bacteria like LAB in gut, improves immunity, protects intestinal cells by altering the membrane permeability [63, 64].

#### *3.1.10 Organic acids*

Butyric acid, Lactic, acetic, tannic, fumaric, propionic, caprylic acids, etc. comes under this category, which had antimicrobial properties, enhance gut structure and alter pathogen gene expression and enhance the performance of birds [65, 66].

### *3.1.11 Polyunsaturated fatty acids*

Fish oil and corn oil are the main source of n-3 fatty acids and n-6 fatty acids, respectively in poultry diets and improves the body's function and immunity [56].

#### *3.1.12 Mycotoxin mitigation*

This limits intestinal damage and suppression of immune responses for application in the gut health arena.

#### **3.2 Immune system in relation to gut health**

Genetically superior birds are in immunologically stress full condition which creating pressure in the producers due to ban of antibiotic growth promoters. This creates tremendous pressure on immune system of the birds by various vaccination schedules.

Feed deprivation at early stage of life delays the development of mucosallayers and process of mucin synthesis in chicks [67].

## *3.2.1 Position of lymphoid tissues associated with mucosa and spread in different organs: mainly GALT*

(Gut associated Lymphoid Tissue): Meckels diverticulum, Payers patches (Intestinal wall), Oesophagus –proventriculus junction, caecal tonsils. Additionally, gallbladder, liver, pancreas, kidney and oviduct are also having some role in protection and immune competence in birds [67].

Gut is the key immunoclogical organ comprises of myeloid and lymphoid cells [68] with its associated structures it forms a site for production of many immune cell types that needed for initiate and mediate immunity.

Immune system in gut depends on microbiota and maturation of the system eliciting by antigen-specific responses mainly influenced by dendritic cells [69]. The non invasive microbes initiates the production of IgA, which controls the host commensal interaction by both impacting commensal gene expression in the lumen and preventing adhesion of commensal bacteria to the epithelial surfaces [70].

#### *3.2.2 Interrelationship between nutrition and immunity*

Poultry encounter numerous stressors during their lives. Alterations in feed intake, poor FCR, varied nutrient metabolism, suppressed immune system are the consequences due to stress [71]. To overcome stress birds defence system prioritise the nutrient utilisation during challenge period [72].

**107**

or not [79].

nutrients on gene expression.

*Gut Health and Immunity in Improving Poultry Production*

**5. Endocrine regulation of gut health in poultry**

integrity and are essential for good out put [78].

**6. Genes that govern gut health and immunity**

Another important factor influences the suppression of immunity as well as production is stress [48]. It may be due to environment (other than comfort zone), diet, vaccination- and medication, microflora imbalance, as well as a result of pathogen or parasitic load [74]. Disruption of gut function may occur and imbalance between production and elimination of ROS is a common phenomenon during stress [48]. Excess ROS in intestine causes destruction of PUFA in the cell membrane and leads to production of peroxides (malondialdehyde) which ruin the intestinal integrity [40]. A compromised epithelium creates a good opportunity for opportunistic pathogens, in addition to this dietary deficiencies in certain nutrients can increase the stress-induced susceptibility of poultry to oxidative stress [48, 49, 75, 76]. The outcome of this is an economic loss to the producer. Improper management makes the poultry exposure to disease causing agents, stress, and Meagre immunity, birds prone to less production or even death [76]. Increased feed efficiency and gut integrity was noticed [77] during in vitro experiments by addition of *Lactobacillus* species which produced bacteriocin Reuterin that might inhibit the growth of *Salmonella, Shigella, Clostridium* and *Listeria*.

Intestinal microbiota structure and function plays a crucial role in health and production of poultry. The micro biota modulates the intestinal homeostasis,

Two types of signals produced by the gastrointestinal tract which influence the feeding behaviour and feed intake, which were in turn influenced by ghrelin, CCK, GLP-1,GLP-2 and PYY and these are released from the intestines and transmit satiety signals to the brain after food intake, resulting in the suppression of appetite [78].

Genes present in the body will regulate all the activities in the body including gut, but in gut, genes do not have any role without the microbiota [78]. It is considered that microbiota will regulate the activity of genes in the gut. The microbiota present in the gut mainly defines the gut condition whether it is in good condition

The main target of Nutrients to alter the activity of genes and results in more activation of good genes and suppresses the activity of bad ones. Through nutrigenomics careful selection of nutrients for fine-tuning genes and DNA present in every cell and every tissue of an animal is possible stated in the review [80]. In **Table 2** results of some the researches were presented regarding influence of

Jiang et al. [86] reported variations in expression pattern of hepatic genes apolipoprotein A-I (ApoA-I) and apolipoprotein B (Apo B) with varying amount of nicotinic acid in feed indicates the lipid metbalosim. Addition of prebiotics likes mannan oligosaccharides (MOS) to broiler diets increases the expression of mucin, and down-regulates selected genes involved in cell turnover and proliferation [78]. Delay in feeding immediately after hatch alters the hepatic gene expression [87]. Nutrigenomics provides a way to identify precisely which nutrient or nutrient

combinations that is optimal to elicit maximum benefits [79].

*DOI: http://dx.doi.org/10.5772/intechopen.95989*

**4. Stress**

Birds immune system get affected by nutrition in several ways [73] like.

a.Development of lymphoid tissues.

b.Mucus Secretion by goblet cells.


*Gut Health and Immunity in Improving Poultry Production DOI: http://dx.doi.org/10.5772/intechopen.95989*
