Use of Additives to Increase Performance and Improve Meat/ Egg Quality in Poultry.
Kaveri Jambagi1, Abhishek Hota2, Sharun Khan3, SL Ali4
1Ph.D Scholar, Division of Medicine, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India. 2Department of Animal Science, M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Parlakhemundi, Odisha, India. 3Ph.D Scholar, Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India. 4Prof. and Head, Department of Veterinary Medicine, Dau Shri Vasudev Chandrakar Kamdhenu Vishwavidyalaya, Durg, Chhattisgarh, India.
Keywords: Broilers, Layers, Enzymes, Prebiotics, Probiotics, Growth, Organic acids, Phytase, Carbohydrase, Gas emission
Various types of natural feed additives such as probiotics, symbiotic, enzymes and organic acids have used as alternative feeding strategies to improve performance production of laying hens. Probiotics are natural living microorganisms including bacteria, fungi or mould. Some strains of bacteria such as Lactobacillus, Enterococcus, Pediococcus, and Bacillus are commercial probiotics. Prebiotics are feed ingredients that cannot be digested and have benefits to the host by stimulating growth and or control metabolic activities in the intestine. Whereas symbiotic or synbiotic are a combination of probiotics and prebiotics. Based on its composition, probiotic bacteria produced and mixed with a substrate that functions as a protector or feed, increases life ability, and maintains beneficial bacteria in the digestive tract. Interactions between probiotics and prebiotics can support the adaptation of probiotics to prebiotic substrates and have an impact on both. Included inorganic acids are lactate; citrate, formate, and a fumarate are a group of salts known to control harmful microorganisms in the digestive and respiratory tracts of birds. The mechanism of adding organic acids by reducing the pH of the stomach and digestive tract and enhancing the immune system.
The addition of probiotics to laying hens known to increase the appearance of production and egg quality. Enzymes, by definition, are chemicals or catalysts released by cells to speed up specific chemical reactions. This definition accounts for enzymes released in the digestive tract to aid in the digestion of food. Today, these same enzymes can be effectively manufactured and added to animal feeds. Three classes of enzymes (phytases, carbohydrases, and proteases) are typically considered for use in poultry feeds. Phytase works by releasing some of the nondigestible phosphorus (and other nutrients) found in commonly used feed ingredients and making the nutrients available for productive purposes. Phytase is a proven technology used to reduce feed cost by reducing inorganic phosphorus supplementation and has the added benefit of decreasing phosphorus excretion in manure.
Carbohydrase enzymes have been proven to be effective in increasing the amount of energy available from feed ingredients. Key carbohydrase enzymes include amylase and xylanase and are used to improve the digestibility of carbohydrates in feed ingredients. This improved digestibility increases the availability of energy in the small intestine to help promote growth and other productive processes. Protease is a protein digesting enzyme that breaks down storage proteins binding starch within feed ingredients. This makes the energy from protein bound starch available to the bird to be used for productive purposes. Proteases are also effective in releasing protein anti-nutrients found in ingredients like soybean meal. This function of proteases makes proteins more available. A combination of amylase, xylanase, and protease enzymes working together to each attack different poorly digestible portions of feed ingredients increases energy available for growth and/or egg production. The addition of these three enzymes to the diet in combination typically increases energy available to birds by 3 to 5%.
Probiotics in controlling bacterial infections and aflatoxins
The possible modes of action of probiotics for the inhibition of pathogens include two basic mechanisms: competitive exclusion and modulation of the host immune system. Competitive exclusion involves mechanisms such as, production of inhibitory compounds, that is, hydrogen peroxide, bacteriocins, and defensins, prevention of the pathogen adhesion, competition for nutrients, and reduction of toxin bioavailability. Meanwhile, in the modulation of the host immune system, both innate and adaptive immune responses are involved. The adaptive immune response depends on B and T lymphocytes to induce an antigen-specific response and produce antibodies. In contrast, physical and chemical barriers (innate immunity), such as intestinal epithelial cells (IEC), are the first line of defense to prevent the spread of pathogens and subsequent infections. Furthermore, IEC are the target cells for probiotics, which can improve the function of the intestinal barrier by stimulating the production of mucus and antimicrobial peptides such as defensins.
Similar as for pathogenic bacteria, probiotics can:
- compete for space and nutrients with aflatoxigenic mold strains,
- degrade aflatoxins by the production of enzymes,
- avoid the intestinal absorption of AFB1 by its binding to the cell walls of probiotic strains.
Probiotics in increased growth performance
Probiotics have been evaluated for their potential to improve growth performance in commercial poultry production since the phasing out of AGP in poultry feed. AGPs work by inhibiting the production and excretion of catabolic mediators by intestinal inflammatory cells, which, in turn, results in reduced intestinal microflora. By contrast, probiotics promote growth by modulating the gut environment and enhancing gut barrier function via the fortification of beneficial intestinal microflora, the competitive exclusion of pathogens, and the stimulation of the immune system. After probiotics supplementation, non-pathogenic bacteria from probiotics compete with the pathogenic bacteria in gut for nutrients; colonize the intestine, leaving no space for harmful bacteria to occupy or establish; and secrete digestive enzymes (viz. β galactosidase, α amylase, etc.), which helps in the increased absorption of nutrients and improves the growth performance of animals.
Probiotics in increased egg laying
The inclusion of probiotics into the diets of laying hens improves laying production by increasing daily feed consumption, increasing nitrogen and calcium retentions, and decreasing intestinal length. It has been proposed that probiotics increase the intestinal fermentation rate and production of SCFA, which provide nourishment for intestinal epithelial cells, which, in turn, leads to improved mineral assimilation. Egg quality typically encompasses several aspects, such as shell weight and albumen and yolk quality. Egg quality has a genetic basis and varies between strains of laying hens. However, the egg quality is also influenced by the housing regimen under which the hens are kept, the age of the laying hens, and the feed used. The egg-laying performance and egg cholesterol content were affected by the probiotic supplementation. Probiotic is an effective supplement for increasing the production performance of laying hens.
Probiotics in enhancing immunity
Probiotic bacteria can induce beneficial effects by producing antimicrobial substances such as SCFA (short chain fatty acids) and bacteriocins that limit the growth and survival of pathogenic microbes. Notably, several strains of Lactobacillus have been found to lower the environmental pH through the production of lactic acid. Probiotics supplementation can modify immunity in poultry. Probiotics alleviates immunological stress in lipopolysaccharide-challenged broilers at an early age, supplementation increased the lysozyme activity in plasma and increased the white blood cell count. Common probiotics such as B. animalis, B. bifidum, L. reuteri, L. acidophilus, S. faecalis, and B. subtilis can produce immune responses in poultry.
Probiotics in modifying gut microbiota
Diverse gut microbiota plays a significant role in host metabolism, growth performance, nutrient digestion, and overall health of birds. The composition of chicken gut microbiota depends on age, especially at the early stages of life, genotype, farming conditions/environment, and diet/feed additives. Sometimes, the gut microbiota composition can be altered severely by non- infectious or infectious stressors. Consequently, this dysbiosis can impact intestinal morphology and activities (e.g., increased permeability of the intestine, higher risk of bacterial infection, sepsis, inflammation, and reduced digestion). Probiotics can affect the health, performance, and disease risk of the hosts, as they can amend the dysbiosis and improve the balance of gut microbiota in healthy hosts by reducing the proliferation of pathogenic species and increasing the beneficial bacteria. The most commonly used probiotic species belong to the genera Lactobacillus, Streptococcus, Bacillus, Bifidobacterium, Enterococcus, Aspergillus, Candida, and Saccharomyces and exert preferential health benefits on the host through the competitive exclusion of deleterious bacteria and the immune modulation in the gut.
Probiotics in mitigating heat stress
Stress is defined as a condition in an animal and poultry that results from the action of one or more stressors that may be of either external or internal origin. A stressor often disrupts standard physiological balance or homeostasis, impacting an animal’s health and performance. For example, during summer and winter seasons, farm animals are exposed to environmental stress due to ambient temperature fluctuation beyond the TN zone. Poultry is homeotherms, and under mild temperature fluctuation, they will try to maintain relatively constant body temperatures by balancing heat loss and HP in their bodies through behavioural and physiological adaptation. However, balancing body temperature through adaptation becomes difficult for birds when temperatures and humidity increase beyond the critical levels, which can be defined as HS. Bird exposure to higher ambient temperature deviation will result in HS condition where behavioural and physiological adaptations will no longer help the birds maintain their body temperature. Several factors could cause HS, including a rise in ambient temperature, increased relative humidity, the harshness of the sun and airflow rate. Unless management interference is made, loss in production and increased mortality will occur.
Certain management practices have been utilized to minimize the detrimental effects of HS. Some management techniques that were used include provision of cold water in houses, use of increased ventilation rate, feeding the birds in the morning and night when temperatures are lower, and supplementation with KCl to encourage water intake. Increased water intake will ultimately lower body temperature since it serves as a heat sink and improves bird survivability. When temperatures are high, broilers want to maintain their body temperature in a certain range. When they respond to HS, they first protect their visceral organs. Heat stress response can start in the hypothalamo–pituitary–adrenal (HPA) axis. Heat stress also affects the orthosympathetic nervous system, which is highly sensitive to high heat temperatures.
The central nervous system seems to be activated by HS, which will cause poor development of the GIT and affect intestinal homeostasis of the broiler. Heat stress has the potential to activate the HPA axis, which may release hormones, such as cortisol-releasing hormone. These hormones may act as neurotransmitters to increase central nervous system activity. Additionally, corticosterone release increased by HS might lower the general immunity of commercial broilers. Ultimately, this reduces their resistance towards pathogens such as coccidia, which could, in turn, develop into necrotic enteritis. When HS is consistent, mortality will increase, feed consumption decreases, as well as BW gain and meat quality. Over the years, growth rate and feed efficiency have been high in the selected category for broilers. Both the high growth rate and increased breast meat yield are encouraged in the broiler production industry. However, these traits are at even higher susceptibility to HS.
Heat stress has caused physiological challenges, which include systemic immune dysregulation, endocrine disorders and electrolyte imbalances. Some reports have also noticed that HS significantly destroys the intestinal mucosa and microbiota. Many factors, including HS, can affect an animal’s microbiome and community of healthy bacteria. Heat stress, disease and diet can negatively influence this environment of bacterial colonization. Heat stress can cause an increase in pathogen colonization, which will inevitably aid in the shedding of the intestinal lining and an increased risk of food safety. Heat stress can expose the bird to immunosuppression, which promotes the onset of both infection and disease. When HS causes damage to the microbiome, it has a devastating effect on intestinal morphology often because of pathogenic bacterial increases. For instance, changes in the villus–crypt structures are observed in the highest amount when birds are in heat-stressed environments. Heat stress has serious consequences on the health and performance of all species of livestock; however, it seems consequences are more severe in poultry, which is mostly raised in confinement. This is due to more energy wastage for thermoregulatory adaption that takes place for the bird to overcome the stress condition and gain weight.
Under mild ambient temperature deviation from the TN zone, poultry makes both behavioural and physiological adaptations to maintain their body temperature. Lying still in their pens, spreading their wings to increase their body surface, increase in water consumption and panting to increase evaporative cooling, and decrease in feed consumption to lower metabolic heat production (HP) and shunt blood to the body surface, along with vasodilation of the blood vessels to increase heat dissipation, are common observations. All these adaptation processes demand energy. Energy consumed by poultry is utilized for the maintenance of vital body functions and growth or production. Of the energy consumed, maintenance energy has to be satisfied first before allocation for weight gain or production. Factors that increase the maintenance need of birds will adversely affect energy left for production and, consequently, impact bird energetic efficiency and cost of production. Among the many factors that affect the maintenance need of birds (age, BW, ambient temperature, feed type, activity, health status, etc.), ambient temperature plays a major role.
Temperature variation outside the comfort zone will cause an increase in HP, which will inversely impact energy left for growth or production purposes. In most commercial farms, birds are raised under controlled environments. Adverse climatic conditions that occur with annual seasonal changes will dispose of birds to temperature fluctuations outside of their comfort zone, especially during winter and summer seasons impacting their health and performance. Poultry has the ability to adapt in situations of energy scarcity, which can be an issue when birds go off feed during HS. Energy scarcity or an excess of caloric energy has changed on the microbial diversity in the gut. The microflora in the small and large intestine can also affect whole-body metabolism by affecting total energy. Throughout evolution, animals had evolved in times of scarcity to maximize the use of calories from various foods or when energy demand was higher than normal. An example of this would be cold exposure. It has been found that cold exposure changes the composition of the microbiome.
The host can increase the intestinal absorptive surface area, resulting in a significant increase in the length of villa and microvilli. This may be the reason to believe that HS could induce microbial changes and gut transformations as well. From what is already known about the ability for probiotics to provide benefits to animal performance and GIT health, this feeding strategy seems applicable to decrease the negative properties of HS. Modern-bred chickens will suffer the worst effects of HS. Similarly, commercial broilers that did well in the spring often underperformed during the summer. Fast-growing broilers have a higher heat output; thus, HS is more pronounced. Birds that grow faster also seem to drink less water in high temperatures, which may result in decreased feed consumption and ultimately lower BW. Chronic HS causes a decrease in protein synthesis and increases protein breakdown, to ultimately reduce protein deposition. Decreased protein synthesis cannot be restored with high dietary protein from the diet. Protein has a high heat increment, but low levels of amino acids cause poor feed efficiency and lowered BW gain. Chickens tend to consume more feed to meet their protein requirement in a low protein ration, which results in increased fat deposition and higher heat output.
Alternatives to Antibiotics: Organic Acids
Several alternatives have been proposed to replace AGPs in the poultry industry including exogenous enzymes, competitive exclusion products, prebiotics, probiotics, herbs, essential oils, acidic compounds, and bacteriophages. Currently, the more common alternatives applied in broiler diets are prebiotics, probiotics, and organic acids. All are utilized with the ultimate goal of ameliorating the condition of the poultry GIT by mitigating the presence of enteric bacteria present in the GIT and improving the performance of the bird. It is of interest to determine how each alternative product specifically achieves improvement in bird gut health. Both organic acids and probiotics appear to have similar mechanistic impacts on bird health as many probiotics improve the physiology and anatomical structure of the intestinal cell wall, enhancement of immunological functions in the GIT, and the increased resistance to enteropathogenic bacteria activity. This occurs either by direct introduction of organic acids including short chain fatty acids (SCFA) in the feed or in the case of probiotic bacteria generating SCFA, hydrogen peroxide, and intermediary metabolites with antimicrobial activity once they become established in the GIT. Organic acids include not only SCFAs but also lactic and formic acids as well as longer carbon chain acids. Prebiotics are also of interest, as they stimulate the proliferation and maintenance of beneficial bacteria such as Lactobacillus, which in return increases the production of SCFA. Thus, organic acid, probiotic, and prebiotic supplements are interlinked because of their role in the production of SCFA and other fatty acids.
Organic acids are organic compounds that retain acidic properties. Most organic acids consist of carboxylic acids (-COOH). Organic acids are primarily composed of SCFAs (≤C6), also commonly referred to as volatile short-chain fatty acids (VSCFA), such as fumaric, propionic, acetic, lactic, butyric, and others. Other organic acids consist of medium-chain fatty acids (MCFA; C7 to C10), and long-chain fatty acids (LCFA; ≥C11).
Growth performance
Active ingredients such as citric acid, malic acid, fumaric acid, and MCFAs are dispersed in a matrix of shell material, a lipid which can allow the active components to reach the intestine in an intact form, and be released slowly by the reaction of lipase from the intestine thereby showing beneficial effects to animals.
Nutrient digestibility
Feed additives, such as OAs in the diets are known to support mechanisms for stimulation of intestinal mucosal growth such a reducing growth rate of many pathogenic intestinal bacteria, decreasing the intestinal colonization and infectious processes, and promoting and maintaining an optimal microbiota, which in turn can reduce the presence of toxins that can negatively affect intestinal morphology, compromise intestinal integrity, and increase the digestion and absorption of nutrients by the mucosa.
Excreta microbial
Gut health is one of the major factors governing the performance of birds and thus, the economics of poultry production while the profile of intestinal microflora play an important role in gut health. Dietary OAs and their salts are able to impair microbial growth in the food and consequently to preserve the microbial balance in the gastrointestinal tract.
Gas emission
Supplementing the diets with 0 to 0.10% of the blend of OAs and MCFAs linearly decreased excreta NH3 gas emission in broilers.
Enzymes as additives in poultry production
The use of enzymes in animal feed is of great importance. Consistent increase in the price of feed ingredients has been a major constraint in most of the developing countries. As a consequence cheaper and nonnconventional feed ingredients have to be used which contain higher percentage of Non-Starch Polysaccharides (soluble and insoluble/crude fibre) along with starch. Non Starch Polysaccharides (NSPs) are polymeric carbohydrates which differ in composition and structure from starch and possess chemical cross linking among them therefore, are not well digested by poultry. A part of these NSPs is water-soluble which is notorious for forming a gel like viscous consistency in the intestinal tract thus by reducing gut performance. Predominantly water soluble and viscous arabinoxylans, which belong to pentosan group, are assumed to be the factor responsible. These pentosans also greatly increase the water intake by the birds, which lead to unmanageable litter problems caused by wet and sticky droppings.
Enzymatic supplementation can improve the nutritive value of cereals containing high levels of soluble non-starch polysaccharides. Several studies have shown that enzymatic supplementation in barley, wheat, triticale or sorghum-based diets can enhance the animal’s performance to a level compared with that obtained in corn-based diets. Commercially, these supplements are characterized by being a cocktail with different enzymes with different specificities. However, different cereals are rich in different and specific non-starch polysaccharides.
Types of Enzyme Available for Poultry
Some of the enzymes that have been used over the past several years or have potential for use in the feed industry include cellulase (ß-glucanases), xylanases and associated enzymes, phytases, proteases, lipases, and galactosidases. Enzymes in the feed industry have mostly been used for poultry to neutralize the effects of the viscous, nonstarch polysaccharides in cereals such as barley, wheat, rye, and triticale. These antinutritive carbohydrates are undesirable, as they reduce digestion and absorption of all nutrients in the diet, especially fat and protein. Recently, considerable interest has been shown in the use of phytase as a feed additive, as it not only increases the availability of phosphate in plants but also reduces environmental pollution. Several other enzyme products are currently being evaluated in the feed industry, including protease to enhance protein digestion, lipases to enhance lipid digestion, ß-galactosidases to neutralize certain antinutritive factors in non cereal feedstuffs, and amylase to assist in the digestion of starch in early-weaned animals
Non-starch polysaccharides
Non-starch polysaccharides are a large variety of polysaccharide molecules, comprising some of the most representative compounds of the cell wall. They can be insoluble or soluble in water. Insoluble non-starch polysaccharides are indigestible, and in normal amounts, they maintain the normal motility of the gut. Soluble non-starch polysaccharides are more susceptible to biological hydrolysis, especially in the last compartments of the birds’ gastrointestinal tract, such as the caecum. Soluble non-starch polysaccharides display an anti-nutritive effect for poultry due to the resulting increase in digesta viscosity.
An increase in digesta viscosity causes a reduction in digesta passage rate and reduces feed intake and digestibility. It also causes a modification in gut physiology that results in an enlargement of the GI tract. The lower passage rate also results in the proliferation of a fermentative anaerobic microflora in the upper compartments of the GI tract.
Digestion
The normal and healthy microflora is composed of facultative anaerobic microorganisms in jejunum and strict anaerobic microorganisms in caecum. The decrease in digestibility is due to an increase in size and stability of digesta layers without motility in mucosa surface leading to a minor contact between feed and enzymes, which leads to a decrease in nutrient availability.
These consequences are more frequent when the carbohydrate degree of polymerization is higher. The digestion of non-starch polysaccharides depends on the animal (presence of microflora able to digest non-starch polysaccharides increases with animal age), the solubility of non-starch polysaccharides, chemical structure of polysaccharide (linkage between sugars determines the fermentation extension of the different carbohydrates) and the amount of non-starch polysaccharides in the diet (anti-nutritive effects of non-starch polysaccharides are related to the concentration of them in the diet).
Health improvement
Coccidiosis problems could be prevented by using enzymes. Birds fed a wheat-based diet with and without glycanase supplementation showed vastly different responses to coccidiosis challenge. Growth was depressed by 52.5% in the control group but by only 30.5% in the enzyme group, which also had a much better lesion score. An increase in digesta passage rate and a reduction in excreta moisture are often noted when glycanases are added to poultry diets, which may be detrimental to the life cycle of the organism. Precision and Flexibility in Least Cost Feed Formulation: Enzymes provide greater flexibility in feed formulation and allow the use of a wide range of ingredients without compromising bird performance and hence provide great flexibility in least-cost feed formulation.
Impact on Environment
Enzymes have been approved for use in poultry feed because they are natural products of fermentation and therefore pose no threat to the animal or the consumer. Enzymes not only will enable livestock and poultry producers to economically use new feedstuffs, but will also prove to be environmentally friendly, as they reduce the pollution associated with animal production. As well as contributing to improved poultry production, feed enzymes can have a positive impact on the environment. In areas with intensive poultry production, the phosphorus output is often very high, resulting in environmental problems such as eutrophication. This happens because most of the phosphorus contained in typical feedstuffs exists as the plant storage form phytate, which is indigestible for poultry. The phytase enzyme frees the phosphorus in feedstuffs and also achieves the release of other minerals (e.g. Ca, Mg), as well as proteins and amino acids bound to phytate. Thus, by releasing bound phosphorus in feed ingredients, phytase reduces the quantity of inorganic phosphorus needed in diets, makes more phosphorus available for the bird, and decreases the amount excreted into the environment.
Enzyme supplementation
As described above, there is a negative correlation between the diet content in non-starch polysaccharides and its nutritive value. To overcome this problem, enzyme supplementation in diets based on cereals rich in non-starch polysaccharides is widely used. The addition of enzymes to monogastric animal diets reduces the degree of polymerization of non-starch polysaccharides, which then have a lower capacity to affect digesta viscosity.
Enzymes need only to cleave the carbohydrate at a few places in the polysaccharide chain to greatly reduce the viscosity of solutions and thus enhance nutritive value. This supplementation improves nutrient digestibility and feed intake, increasing the animal’s performance. The polysaccharide disruption not only reduces the viscosity but also releases nutrients and thus increases the feed metabolizable energy. Barley and oats are rich in β-glucans, which are responsible for the low nutritive value of the diets based on these raw materials. Feed supplementation with β-glucanases decrease the polymerization degree of β-glucans, allowing a better use of the nutrients released, and leading to an increase in feed intake and to a decrease in the feed conversion ratio. Arabinoxylans are the major contributors to soluble non-starch polysaccharides released from wheat, rye and triticale. In the same way, also xylanases can depolymerize this substrate and improve its nutritive value.
Benefits of Enzymes
Benefits of using feed enzymes to poultry diets include; reduction in digesta viscosity, enhanced digestion and absorption of nutrients especially fat and protein, improved Apparent Metabolizable Energy (AME) value of the diet, increased feed intake, weight gain, and feed–gain ratio, reduced beak impaction and vent plugging, decreased size of gastrointestinal tract, altered population of microorganisms in gastrointestinal tract, reduced water intake, reduced water content of excreta, reduced production of ammonia from excreta, reduced output of excreta, including reduced N and P.
Factors Affecting the Benefits of enzyme
The degree of improvement obtained by adding enzymes to the diet depends on many factors, including the type and amount of cereal in the diet; the level of antinutritive factor in the cereal, which can vary within a given cereal (for example, low- versus high-ß-glucan barley); the spectrum and concentration of enzymes used; the type of animal (poultry tend to be more responsive to enzyme treatment than pigs); and the age of the animal (young animals tend to respond better to enzymes than older animals); type of gut micro flora present and the physiology of the bird. Older birds, because of the enhanced fermentation capacity of the micro flora in their intestines, have a greater capacity to deal with negative viscosity effects. Use of enzymes in layers:
Although the majority of research trials were conducted on broilers. However, the responses of laying hens to enzyme-supplemented feeds are also well documented. Typically, enzymes added to layer feed appear to have little effect on egg mass but improve feed efficiency, energy utilization. Increased energy utilization in laying hens appears to be due to microbial fermentation of solubilized NSPs and the subsequently higher absorption of volatile fatty acids. Wet litter arising from the use of barley and newly harvested wheat can result in an increased incidence of dirty egg shells and in ammoniabuildup in poultry barns. Adding enzymes to both wheatand barley-based diets has been shown to reduce the moisture content of fecal matter in layers.
Advantages of single specific enzymes
Several studies have shown equal or better results in broilers’ performance when a single specific enzyme is used compared with a commercial mixture. This suggests that it is possible to use just one enzyme, which could save feed producers money in enzyme supplementation. Besides the supplementation with enzymes, it is also important to evaluate the need of the supplementation. It has been shown that endogenous enzymatic activity is encountered in some crops, such as barley.
Additionally, some study results have shown that exogenous supplementation is redundant when some barley varieties are used. This redundancy was explained by a high endogenous enzymatic activity in barley crops that was shown to be satisfactory for the improvement of nutritive value of this cereal. This was evaluated by the decrease in digesta viscosity and improvement in the animal’s performance.
Justifying enzymatic supplementation
It seems that it is very important to evaluate the endogenous activity of the grains to justify the use of enzymatic supplementation. It is also known that different cereal grains have different non-starch polysaccharides content. From low to higher contents: rice, sorghum, corn, wheat, triticale, rye and barley. Non-starch polysaccharides content also seems to be dependent on some other factors, such as crop variety and environmental growth conditions. Different varieties of the same cereal may have different non-starch polysaccharides content and consequently have a different impact on animals’ performance. Using specific enzymes in poultry nutrition makes it possible to use cereals with lower nutritive value. Cereals with lower nutritive value usually have lower prices, which may be an opportunity for feed producers.
Enzyme engineering can be part of a solution to the feeding problem in poultry. Enzyme engineering based on most efficient microorganisms, together with the use of recombinant genetic manipulation, can improve enzyme efficiency and consequently can help increase the widespread use of cereals as a corn alternative.
Conclusion
Probiotics are considered a captivating feed additive because of their immense empirical benefits: improvement in the gut microbiological homeostasis, immune response, growth, and laying performances. The use of probiotics in poultry production may address the public health concerns of antimicrobial resistance development to some extent, as this could replace the use of some sub therapeutic antibiotics. The use of enzymes as a feed additive has rapidly expanded. In the last decade, extensive studies have been conducted to study the effects of feeding exogenous enzymes on the performance of poultry. Although the economic and social benefits of enzymes have been well established and the future of feed enzymes is a bright one. Any advances in this field must ultimately improve the welfare of chickens, reduce the production of wastes and conserve resources. Dietary supplementation of the protected blend of OAs and MCFAs improved growth performance and nutrient digestibility, shifted microbiota by raising excreta Lactobacillus counts, and decreased excreta NH3 gas emission.
