*1.4.4 Aflatoxin control*

Contamination of feed and food with aflatoxins occur during the preparation value chain. Several methods have been adopted in the prevention of aflatoxicosis in animal origin. Application of Good Agricultural Practices (GAP) are important strategy during pre-harvest. Appropriate GAP includes crop rotation, soil cultivation, irrigation and proper use of chemicals. Crop rotation is important and focuses on breaking the chain of infectious material, for example by maize/legume rotations. Any crop husbandry that includes destruction, removal or burial of the infected crop is seen as good soil cultivation. The deeper the soil is inverted (plowing), [76]. Reducing plant stress by irrigation is also valuable to prevent fungi infestation [77]. Damages caused by insects, birds and rodents increases susceptibility of aflatoxin invasion. Successive fungal infection must by controlled by appropriate use of critical pest management system and application of fungicides [77]. Climate change such as high temperature, relative humidity and drought influenced mold infection and mycotoxin production [17].

Mycotoxin are prevented during storage by improving the post-harvest storage conditions [78]. Jard et al. [79], reported storage of grain at less than 15% moisture, removal of infected grain by insect and visibly damaged this prevent favorable condition for mold growth, combination of multiple strategies to reduced moisture content of grain and prevent mold formations. Mycotoxin are destroyed, inactivated, or generate non-toxic products which do not altered the nutritional quality of the food or feed [79]. There are several decontamination processes which include radiation, oxidation, reduction, ammonization, alkalization, acidification and deamination [17]. These chemical methods are not allowed in the European Union [12] as chemical transformation might lead to toxic derivatives. In the United States, only ammonization is licensed for detoxifying aflatoxins.

#### *1.4.5 Detoxifying*

Detoxification of agricultural commodities through; radiation, oxidation, reduction, ammonization, alkalization, acidification and deamination is restricted due to problems associated with incomplete detoxification, cost implication and unavailability of equipment. Commonly used method to reduce mycotoxin exposure in the field is the inclusion of mycotoxin detoxifying agent in feed (mycotoxin detoxifiers) which decreases the bioavailability of the toxin [79, 80]. There are two different class of detoxifiers, namely mycotoxin binders and mycotoxin modifiers. The modes of action differs; mycotoxin binders adsorb the toxin in the gut, resulting in the excretion of toxin-binder complex in the feces, whereas mycotoxin modifiers transform the toxin into non-toxic metabolites [34]. Detoxifier are extensively use as feed additives for the reduction of contamination of feed by mycotoxin; which modify their mode of action, reduce absorption and secretion of metabolites [34]. Detoxifier does not mean that animal feed exceeding maximal regulatory limits used. Quality of feed can be improve by adding detoxifier making the product acceptable in market and providing safety for animal health [80].

#### *1.4.6 Organic binder*

Lactic acid bacteria (LAB), are divided into four genera: Lactococcus, Lactobacillus, Leuconostoc and Pediococcus. They are Gram-positive, catalasenegative, non-sporulating, usually non-motile rods, cocci, ferment carbohydrates, produced lactic acid [81]. Lactic acid bacteria are used in food processing industry for fermentation, preservation and mycotoxin binding abilities [82]. The mechanism of interaction involves the peptidoglycan structure (amino acid) which are common site for binding. However, different mycotoxin have different binding sites [82].

#### *1.4.7 Probiotics*

Application of biotechnological tools to reduced chemical residues and improved production efficiency that does not create any harm to poultry as well as consumers of the value chain [83]. Recent advancement in biotechnology on poultry feeds, banning of harmful growth promoters and antibiotics. Globally, probiotics is gaining acceptance in feed formulation [83]. Antimicrobial resistance is now a worldwide threat [84] with alteration of immune response due to feeding of antibiotic growth promoters, Probiotics are considered as an important tool as regard to antimicrobial resistance [85]. Chick gut are usually sterile immediately after hatch, colonization of microflora on the gut occur on the hatching tray, hatcher, feed and water intake. These Microorganisms in the gut could either be beneficial or harmful based on their response to the host immune system. The beneficial organisms maintain gut equilibrium, improve health and production of the birds. However, harmful bacteria like *E. coli, Salmonella, Coliform* and *Campylobacter* adjust the gut equilibrium to favor spread of infection. Probiotics supplementation mitigate the spread of infection on poultry. Commercial probiotics preparation can be administer as a single or multi-strain where they positively improved production and egg shell quality [86]. Probiotics depends on several factors for their survival on the host, this include; dose frequency, type of host animal, strain and stability of organism, genetic component of host, nutritional status of host age and physiological levels [87, 88]. Research findings showed that use of probiotics in layer diets enhanced egg production, improve body weight [89–92], reduced serum low density lipoprotein (LDL) cholesterol [93], decrease cholesterol and triglycerides in blood [94, 95]. Probiotics improved shell quality hardness and bone strength in laying hens [96]. Improvement in the production of darker yolk color Sobczak and Kozłowski [90].

#### *1.4.8* Lactobacillus spp. *and* Bacillus spp.

Physical and chemical detoxification are associated with some disadvantages such as undesirable effects on products, loss of nutritional quality and altered organoleptic properties, high cost of production and time consumption [97].

#### *Benefits of Probiotics on Aflatoxin Infected Birds DOI: http://dx.doi.org/10.5772/intechopen.99800*

Antibiotic are used in poultry to treat an infection, growth promoter and productivity thus causes antimicrobial resistance to the health of livestock and consumers of the bye products [98]. Multi-drug resistance genes (MDRG) occurs due to under administration, overdose, drug residues and extra label use of drugs which is emerging in both animal and human due to continuous use of antibiotic in the diet of poultry. However, biological methods based on competitive exclusion where probiotics colonized adhesive sites on the intestinal epithelium thereby, prevent colony formation of pathogenic bacteria, non-toxigenic fungal strains have been reported promising method for lessening the formation of mycotoxins and preventing their absorption animal to human [87, 99]. Lactobacillus, Bifidobacterium, Propionibacterium, and Lactococcus are found to be active in terms of binding AF-B1 and AF-M1 [97, 100, 101]. Probiotics are alternatives for growth promotion, food safety, enhanced nutrient assimilation, improve production and reducing harmful bacterial concentration of the gut [87, 102, 103]. Binding of aflatoxin depend on several factors such as temperature, incubation time, pH, matrix and strain of probiotics [104]. Probiotics act as antagonist against aflatoxin, by altering metabolism of gastrointestinal tract, production of volatile fatty acid, organic acid, antibacterial (lactocidin, acidophillin, bacteriocins and hydrogen peroxide), stimulation of essential nutrient for immune responses and inhibiting bacteria growth [105, 106]. Absorption of nutrient and digestive activity are increase with decreased in ammonia production and bacteria enzyme activity (glucoronidase, nitroreductase, azoreductase) produced by pathogenic bacteria. They stimulate immune system by higher production of immunoglobulins, macrophages, lymphocytes, γ-interferon increase villus height, goblet cells and crypt depth to create environment unfavorable to agent [107]. Strain composition and doses determines the potentiality of probiotics [86]. Single strain probiotics exact direct mechanism of action but for multi-strain, it exact synergistic synergistic action among different strains and in such condition, it is supposed that multi-strain probiotics have more adhesive power than single strain [108].

#### *1.4.9 Intestine*

Intestine and the intestinal epithelial cell layer are selective barrier between external and internal environment. The first barrier layer prevent exposure of high concentration of foreign antigens, natural toxins, pathogens and mycotoxin [109, 110]. Intestine are maintained by well-organized intercellular structures including tight junctions, adherence junctions and desmosomes surrounding the apical region of epithelial cells [111]. Physical and chemical factors can dynamically alter the structure and function of tight junctions. The trans-epithelial electrical resistance (TEER) of cell monolayers can be considered as a good indicator of the epithelial integrity and of the degree of organization of the tight junctions over the cell monolayer [112]. The primary function of intestinal cells are to act as a physical barrier, separating the contents of a harsh luminal environment from the layers of tissue comprising the internal milieu [113]. Intestinal epithelial cell studies performed on rats indicate that aflatoxin B1 decreases intestinal cell proliferation throughout the intestine [114]. The intestinal epithelial cells barrier function as both on innate and adaptive components of immunity [113].

#### **1.5 Immune response**

Various mycotoxins affect immune-related organs and cells, and influence host defenses against infectious agents and related microbial toxins [115]. Aflatoxins suppress immune functions, particularly cell-mediated immune responses [116].

For instance, high levels of aflatoxin B1 (AFB1)-albumin adducts change T-cell phenotypes and reduce the percentage of B cells in human immunodeficiency virus-positive individuals [117]. In addition to lymphocytes, embryonic exposure to AFB1 impairs the functions of phagocytes such as macrophages and neutrophils, via the depression of phagocytic potential, inhibition of antiviral activity, and reduction in chemotactic responses [118–120]. AFB1 also interferes with the innate immunity of macrophages by suppressing tumor necrosis factor-α (TNF- α), interleukin (IL)-1, and IL-6, resulting in the disruption of pulmonary and systemic host defenses [67, 121].
