APPLICATION OF HERBAL FEED ADDITIVES IN POULTRY NUTRITION

Herbs and plant extracts used in animal feed, called today phytogenics feed additives (PFA), are defined as compounds of plant origin incorporated into animal feed to enhance livestock productivity through the improvement of digestibility, nutrient absorption and elimination of pathogens residents in the animal gut ( Kamel, 2001; Balunas and Kinghorn, 2005; Athanasiadou et al., 2007) .

The large variety of plant compounds used as PFA are assembled according to their origin and treatment, such as herbs and spices (eg: garlic, anise, cinnamon, coriander, oregano, chili, pepper, rosemary and thyme) but also essential oils or oleoresins (Kamel, 2000). Another category of compounds are extracted exclusively from fruits. They are represented by water soluble polyphenols (flavonoids) which can also be used in animal feed (Lopez –Bote, 2004). Antimicrobial compounds are commonly added to poultry diets for growth promotion and disease control at lower therapeutic doses on the basis of the observations made since 1946 (Demir et al., 2005; Kim et al., 2008; Elagib et al., 2015). Misuse of antibiotic drugs can cause drug resistance bacteria and antibiotic residue in animal products (Costa et al., 2007); therefore, natural antimicrobial products have been considered as indispensable resources (Ferrini et al., 2008). It has been shown that the use of antibiotic growth promoters among the poultry feed have been banned since 2006, although they play a beneficial role in growth performance and disease prevention among the broiler chickens by developing resistance in bacteria and presence of drug residues in meat (Gilani et al., 2018). The feed grade antibiotic growth promoters have been banned due to cross-resistance and the risk of possible drugs multiple resistances in human pathogenic bacteria. Natural products of plant origin, like spices, herbs, and many plant extracts can be used as alternative to antibiotics for growth promotion to improve broiler performance (Hernandez et al., 2004). Herbal extraction is considered as a useful growth promoter of similar effects, which is similar to antibiotics, when used in broiler feeds (Elamin et al., 2015). The earliest known use of vinegar was more than 10,000 years ago.

Rhizome or root part of ginger (genus Zingiber) is extensively employed in medicine for the management of different diseased conditions; like nausea, vomiting, motion sickness, gastrointestinal ulcers, diabetes, fever, arterial tension, rheumatoid arthritis, dry mouth/ xerostomia, cancer, migraine headache, sore throat, and minor respiratory ailments. Zingiber officinale Roscoe, commonly known as Ginger, belongs to the Zingiberaceae family (Riaz et al., 2015). The fat content of broiler carcasses is likely to increases by using drugs as feed additives (Aletor et al., 2000). Thus, the recent nutritional plans for feed cost reduction have resulted in fatty broiler carcasses (Ademola et al., 2009). The nutritional strategies aim to reduce the feed costs that leads to the production of fatty broiler carcasses (Ademola et al., 2009). The natural herbs, including ginger power and apple cider vinegar, are known to possess lipid reducing effects and promote growth, similar to antibiotics, when used in the feeds of broiler chicken (Elagib et al., 2013). The natural feed additives are capable of enhancing poultry production and broiler performance through improved nutrient digestion and absorption by reducing enteric pathogenic microbial loads. Good health status is likely to be maintained among the broiler chickens that is contributed through the buffering capacity of diets. Moreover, the buffering capacity is likely to be enhanced through the supplementation of organic acids (Papatsiros et al., 2012). Ginger has gained prominence due to its wide range of properties with the basic aim of improving the nutritive value of animal product (meat, milk or egg). The ginger protease could be useful in the tenderization process and improving the quality of meat (Naveena & Mendiratta, 2001). Apple cider vinegar is broken down into alcohol and later into vinegar by the yeast and bacteria after it is consumed by the broiler chicken. On maturation, vinegar turns into cloudy dark substance. Acetic acid is the main ingredient of apple cider vinegar. On the other hand, the efficacy of ginger powder makes it a potent compound for treating wide range of diseases. However, rapid removal and inactivity of metabolic compound decrease the availability of the agent.In modern poultry production, PFAs are used for the purpose of antimicrobial effect, digestibility enhancement, performance improvement, and many others

 Beside the feed enzymes, probiotics (for monogastric animals mainly lactobacilli), prebiotics (oligosaccharides), organic acids, the herbs and botanicals can be used as feed additives. A definition can be derived from Webster’s Encyclopedic Unabridged Dictionary of the English Language (1989):

Herb: A flowering plant whose stem above ground does not become woody and persistent. A plant when valued for its medical properties, flavor, scent, or the like.

Spices: Any of a class of pungent or aromatic substances of vegetable origin, as pepper, cinnamon, cloves, and the like, used as seasoning, preservatives, etc.

Botanical: A drug made from part of a plant, as from roots, leaves, bark etc. Essential oils are any of a class of volatile oils obtained from plants, possessing the odor and other characteristic properties of the plant, used chiefly in the manufacture of perfumes, flavors and pharmaceuticals (Extracts after hydro – distillation).

Different herbal feed additives, its active components and functions

(Source: Mirzaei-Aghsaghali, 2012)

MODES OF ACTION OF HERBS AND BOTANICALS

Beneficial effects of herbs or botanicals in farm animals may arise from activation of feed intake and secretion of digestive secretions, immune stimulation, anti-bacterial, coccidiostatic, anthelmintic, antiviral or anti-inflammatory activity and inhibition or – particularly – antioxidant properties. Most of these active secondary plant metabolites belong to the classes of isoprene derivatives, flavonoides and glucosinolates, and a large number of these compounds has been suggested to act as antibiotics or as antioxidants in vivo as well as in food. A main activity takes place in the digestive tract. Herbs or the phytochemicals can influence selectively the micro-organisms by an anti-microbial activity or by a favorable stimulation of the eubiosis of the microflora. The consequence can be a better nutrient utilization and absorption or the stimulation of the immune system. Finally herbs can contribute to the nutrient requirements of the animals and stimulate the endocrine system and intermediate nutrient metabolism. Immune system and a stable, beneficial microflora (eubiosis) must be buildup. For that a regular intake of feed and water is of a high priority. Often the desired activity of herbs is not constant. Conflicting results may arise from the natural variability of the composition of plant secondary metabolites. Variety and environmental growth conditions, harvesting time and state of maturity, method and duration of conservation and storing, extraction method of the plants, as well as possible synergistic or antagonistic effects, anti-nutritional factors or microbial contamination are factors which may substantially affect the results of in vivo experiments.

The herbal feed additives exert their beneficial effects by

• Influence of herbal feed additives on feed intake, digestibility of nutrients and animal performance:

After the ban on antibiotics, more herbs are used as feed additives for a better growth condition. Due to the wide variety of active components, different herbs and spices affect digestion processes differently. Most of them stimulate the secretion of saliva. Curcuma, cayenne pepper, ginger, anis, mint, onions, fenugreek, and cumin enhance the synthesis of bile acids in the liver and their excretion in bile, what beneficially effects the digestion and absorption of lipids. Most of the prelisted spices stimulate the function of pancreatic enzymes (lipases, amylases and proteases); some also increase the activity of digestive enzymes of gastric mucosa. Besides the effect on bile synthesis and enzyme activity, extracts from herbs and spices accelerate the digestion and shorten the time of feed/food passage through the digestive tract (Frankic et al., 2009). Plant herbs such as garlic (Allium sativum), lemon grass (Cymbopogon citrates) and peppermint (Mentha piperita) are widely used as antibacterial agents and extensively used to maintain the microbial ecosystem of the gastrointestinal tract especially in tropical regions (Shin and Kim, 2004). Garlic as an alternative growth promoter in livestock production reported improved growth rate, digestibility and carcass traits (Kongmun et al., 2011). Lemongrass and peppermint have been reported as feed additives to improve production performance of beef and dairy cattle (Yang et al., 2007). Recently menthol (Mentha arvensis) is reported to improved ileal protein and amino acid digestibility thus feed efficiency in weaned piglets (Maenner et al., 2011) and black paper improved performance in broiler chicken (Tazi et al., 2014).

• Herbal feed additives as antimicrobial supplements: Several studies showed strong antimicrobial activity of certain plant extracts against Gram- and Gram+ bacteria. Plants readily synthesize substances for their defense against insects, herbivores, and Moreover, they may produce secondary antimicrobial metabolites as a part of their normal growth and development or in response to stress. Several researches have studied the antimicrobiol effect of oriental herbs including Allium sativum, Angelica dahurica, Anguisorba officinalls, Artemisia argyi, Coptis chinensis, Dictamnus dasycarpus, Fraxinus rhynchophylla, Geranium thunbergii, Hydrastis canadensis, Phellodenron amurense, Polygonum cuspidatum, Scutellria baicalensis and Sophora flavesens. These herbs contain major flavonoid components, baicalin, baicalein, limonene, cinnamaldehyde, carvacrol or eugenol which exerts antimicrobial effect along with other supportive herbs.

These herbs have antibacterial effect against Salmonella spp or E. coli and gram positive bacteria Staphylococcus spp. and Streptococcus spp. Active principles in herbal feed additives changes fatty acid composition which can affect surviving ability of microorganisms by increasing hydrophobicity. This confirms the fact that herbs and spices act as antimicrobial agents by changing the characteristics of cell membranes, and causing ion leakage, thus making microbes less virulent. Plant extracts, known as phytobiotics, have been exploited for their antimicrobial, anti-inflammatory, anti-oxidative, and anti-parasitic activities. There is a lot of variations in the composition of phytobiotics due to the biological factors (plant species, growing location, and harvest conditions), manufacturing (extraction/ distillation and stabilization) and the storage conditions (light, temperature, oxygen tension, and time; Huyghebaert et al., 2011).

• Herbal feed additives as anti-inflammatory: Extracts of curcuma, red pepper, black pepper, cumin, cloves, nutmeg, cinnamon, mint and ginger showed anti-inflammatory effect. The major active molecules with anti-inflammatory action are phenols, terpenoids and These molecules suppress the metabolism of inflammatory prostaglandins. Phenolic compounds of plants are hydroxylated derivatives of benzoic acid and cinnamic acids and have been reported to possess anti-inflammatory effects. Flavonoids have long been recognized to possess antiinflammatory, anti-allergic, antiviral and antiproliferative activities (Muanda et al., 2011). The most known herbs and spices with anti inflammatory potential are chamomile, marigold, liquorice and anis (Frankic et al., 2009). Plants of the Labiatae families (like mint) have attracted a great interest. Their antioxidative activities are due to phenolic terpenes (Cuppett and Hall, 1998). Thyme and oregano contain large amounts of monoterpenes, thymol and carvacrol (Rahim et al., 2011). Plants rich with flavonoids such as green tea and other Chinese herbs have been described as natural antioxidant (Wei and Shibamoto, 2007). Black pepper (Piper nigrum), red pepper (Capsicum annuum L) and chili (Capsicum fretuscene) contain also several antioxidative compounds (Nakatani, 1994). But in many of these plants, the parts containing the active substances are of a very fragrant and/or spicy taste leading to restrictions of their use in animal feed. Recently anti-bacterial, anti- viral, anti-fungal, anti-tumor, anti-inflammatory, immunomodulatory, wound-healing, anti- oxidant, and anti-diabetic effects properties of Aloe vera have been reviewed for poultry (Babak and Nahashon, 2014).
• Herbal feed additives as antioxidants: Antioxidants are compounds that help delay and inhibit lipid oxidation and when added to foods tend to minimize rancidity, retard the formation of toxic oxidation products, and help maintain the nutritional quality (Muanda et al., 2011). The healthpromoting effect of antioxidants from plants is thought to arise from their protective effects by counteracting reactive oxygen species. Several studies suggested that plants rich in antioxidants play a protective role in health and against diseases, and their consumption lowered risk of cancer, heart disease, hypertension and stroke. The antioxidant potential of medicinal plants may be related to the concentration phenolic substances (flavonoids, hydrolysable tannins, proanthocianidins, phenolic acids, phenolic terpenes) and some vitamins (E, C and A). Garlic and onion biological action products are ascribed to its sulfur-containing active principle which has been reported to their lipid lowering effects and inhibit oxidation of low-density lipoproteins (Ahmed and Bassuony, 2009). Often used herbs rich in phenolics are: rosemary, thyme, oregano, sage, green tea, chamomile, ginko, dandelion and marigold. Herbs and spices can protect the feed against oxidative deterioration during storage.

Anti- and pro-oxidative properties of essential oils

(Deans et al., 1993)

• Herbal feed additives as immunostimulant: The immune system generally benefits from the herbs and spices rich in flavonoids, vitamin C and The plants containing molecules which possess immunostimulatory properties are echinacea, liquorice, garlic and cat’s claw. These plants can improve the activity of lymphocytes, macrophages and NK cells; they increase phagocytosis or stimulate the interpheron synthesis (Frankic et al., 2009). Lavinia et al. (2009) have shown that essential oils extracted from medicinal plants improve the immune response and also are able to cause changes of the duodenal mucosa with beneficial effects for the animal (Lavinia et al., 2009). Recently effect of ß- glucan and cow urine distillate have been highlighted as immunomodulator in broiler chicken (Ganguly, 2013).

• Herbal feed additives as coccidiostat: some plant extracts have demonstrated an activity against some chicken parasites, especially coccidian (Naidoo et al., 2008) Betaine is a byproduct of the sugar beet industry; it has recently been seems to have a positive impact in fighting It protects against osmotic stress associated with dehydration and permits normal metabolic activity of cells. However, the protective effects of betaine on the intestinal cells are also exerted on parasitic cells. The active component is curcumin; a phenolic compound coming from the rhizome of Curcuma longa exerts its anticoccidial effect through its antioxidant action on the immune system. Galla rhois and Nectaroscordum tripedale extracts have shown promising result against coccidial infection.

Advantages of Herbal Feed Additives

Selection and feeding of herbal feed additives over other feed additives is due to

• Natural constituent of
• Absence of residual effects.
• Non-hazardous eco-friendly.
• Minimum problem of drug

 Limitations of Herbal Feed Additives

• Not easily quantifiable and standardized due to their complex
• The location, soil type, weather conditions, altitude, season during which the plant is grown, harvesting procedure and storage conditions may affect the composition of
• Although majority of herbals are stable, there are various constituents which are photo labile thermo labile thus less stable.
• Variety and environmental growth conditions, harvesting time and state of maturity, method and duration of conservation and storing, extraction method of the plants, as well as possible synergistic or antagonistic effects, anti-nutritional factors or microbial contamination are factors which may substantially affect the use of herbal feed.

CONCLUSION

In the concept of the production of healthy farm animals without the use of antibiotics herbs can be relevant in many different ways. They can regulate feed intake and stimulate digestive secretions. An optimized digestion capacity and reduced risk of digestive disorders are the consequence. Several phytochemicals like essential oils or dietary fiber can contribute to a balanced microflora (eubiosis), an optimal precondition for an effective protection against pathogenic micro-organisms and an intact immune system. Herbs and botanicals contain many different antioxidants with a high potential for the protection of nutrients against oxidation in the digestive tract, in metabolism as well as in the products.

DR A. RAJKUMAR,MANIPUR

REFERENCES

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• Babak, and Nahashon, S.N. 2014. A review on effects of Aloe vera as a feed additive in broilerchicken diets. Annals of Animal Science, 14 (3): 491–500.
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