feed additives for livestock and poultry

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  • Dr. Pankaj Kumar SinghAssistant ProfessorDepartment of Animal NutritionBihar Veterinary College, Patna, Bihar, IndiaE-mail: vetpank@gmail.comFEED ADDITIVES FOR LIVESTOCK AND POULTRY

    P.K.SINGH

  • IntroductionThe production of food by livestock results from combined effect of

    genetic capacityfeed quality andefficiency of feed conversion Production and its efficiency can be improved by minimizing costs incurred during digestion and metabolism There is also urgent need of controlling the negative impacts of pollutants from animal agriculture

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  • Feed additives are commonly described as non-nutrient substances that accelerates growth, efficiency of feed utilization, or beneficial for health, or metabolism of the animal Range of additives used in the animal production industry is very broad They are growth promoters, disease preventing agents and auxiliary substancesThough not essential from the stand point of nutrition, they play a role in improving palatability, physical characteristics and preventing rancidity of feedFeed additives are used in the diets in very small quantities and beneficial effect of the most of the feed additive is more in young animals

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  • Broad classification of feed additives

    Growth promotersDisease preventing agentsSupplements/VitaminsAuxiliary substancesI. Chemical (1) Ionophores1. Antibiotics1.Organic trace elements1.Plant extract/herbal products2. Coccidiostats2.Synthetic vitamins2. Antioxidants(2) Antibiotics3. Mould inhibitors3.Synthetic amino acids(3)Flavouringagents/pigmentation compounds(3) Arsenicals4.Non protein N(4) Emulsifiers(4)Prebiotics/oligo -saccharides5.Branched chain VFA(5)Hormones and B- agonists(5) Buffers(6) Preservatives (6)Defaunating agents(7) Pellet binders(7)Organic acids/ Feed acidifiers(8)AdsorbentsII. Biological (1) Probiotics(9)Methane inhibitors

    (2) Enzymes

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  • Antibiotics

    Antibiotic is a product of microbial origin capable of controlling the multiplication of another microorganism either through killing or inhibiting further multiplication

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  • Non-Ionophore AntibioticsMetabolic effect

    thinning of the gut wall associated with changes in ultra structure and enzyme activities of epithelial cells Hence, enhances nutrient absorption and lower the metabolic energy cost Nutrient sparing effect

    The antibiotics alter the bacterial population resulting in conservation of nutrients Control of sub clinical disease

    Disease free animals do not respond to antibiotic feedingGrowth promotion partly attributable to disease preventionModification of ruminal fermentation

    The antibiotics alter rumen microbial population to improve fermentation efficiency.

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  • Non ionophore antibiotics used alone or in combination in ruminants B-Bloat prevention F- Feed efficiency G- Growth promotion L- Liver abscess control M- Medicinal

    AntibioticsBeef productionDairy cowsCalvesSheep/goatAvoparcinF, GF, G-F, GBacitracinL---Zinc BacitracinF, G, M.M,--ChlorletracyclinF, G, L, MMF, G, MF, G, MFlavomycinF, G---Neomycin--M-OxytetracyclinB, F, G, L, MB, MF, G, MF, G, MSpiramycin--M-TylosinL---VirginiamycinF, GM--

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  • Effect of antimicrobial feed additives on ruminal metabolic reactionsD, decrease; I, increase; 0, no effect; ND not determiDed; A, acetate; P, propionate

    Feed additivesFibre degradationVFALactate productionMethane productionAmino-N degradationAmmonia concentrationTotalA/P ratioAvoparcin00DDDDDBacitracinDD0DDDDChlortetracyclineDDIIDDDFlavomycinI000000NeomycinND00NDNDND0OxytetracyclineDDI0NDND0SpiramycinNDDINDNDNDNDTylosinDDIDNDNDNDVirginiamycinNDDDDD0D

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  • Ionophore Antibiotics compounds possessing the ability to form lipid soluble complexes with cat ions and mediate their transport across lipid barrierscarboxylic ionophores-form electrically neutral complexes with mono or divalent cat ions and catalyse electrically silent exchanges of cat ions for protons or other cat ions across a variety of biological membranes

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  • Ionophore AntibioticsMode of action

    Increased production of propionate and decreased production of methane resulting in increased efficiency of energy metabolism. Decreased protein degradation and deamination of amino acids resulting in the improvement of nitrogen metabolism in the rumenDecreased lactic acid production and foam formation in the rumen leading to reduction of ruminal disorders

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  • Ionophores are generally bacteriostatic not bactericidal Highly effective against gram +ve bacteria but exhibit little or no activity against gram negative bacteria Gram negative bacteria possess an outer membrane that contains protein channels (porins) with a size exclusion limit of approximately 600 DA (Ionophores >600 DA), Gram +ve bacteria do not have an outer membrane and hence are much more susceptible to the action of Ionophores. Ruminal bacteria that produce Lactic acid, butyric acid, formic acid and succinic acid are susceptible and Bacteria that produce succinic acid and propionic acid are resistant to ionophore antibiotics

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  • Limitations methanogens adapt to ionophores after prolonged exposurefeeding ionophores may affect the absorption and retention of certain minerals especially magnesium As ionophores are lipophilic, inclusion of fat in the diet may alter ruminal distribution and/or access of ionophores to methanogenic microbes

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  • ArsenicalsArsenic compounds, namely arsanilic acid, sodium arsanilate and 3 -nitro-hydroxyphenyl arsenic acid are also used as growth inhibitors for pathogenic organism and to restore conditions of recovering animals The amount of arsenic retained in the tissues is very lowIt is desirable to discontinue arsenicals from the diet at least 5 days before slaughterArsenicals are added @ 50-70 g/tone of feed

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  • Buffering compoundsBuffers are mixtures of weak acids and their conjugate bases When present in aqueous solution, buffers should resist changes in pH upon addition of acid or base In ruminant nutrition, the term buffer is applied loosely to include oxides or hydroxides that neutralize acids present in feed stuffs or acids produced during ruminal fermentation A more appropriate term is neutralizing or alkalinizing agents

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  • Mechanism of action Buffer modify ruminal fermentation by

    (I) increasing or resisting change in ruminal pH and (2)Increasing fractional outflow rate through the reticulo omasal orifice ( ruminal dilution rate) The increase in fluid dilution rate is due to increased osmolarity which increases both water intake and influx through the ruminal wall

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  • Buffers like sodium bicarbonate and magnesium oxide are used routinely in dairy cattle, to counteract the depression in milk fat synthesis due to low ruminal pH and reduced acetate/propionate ratio induced by a low roughage and high grain diet Supplements of sodium bicarbonate should be 0.6 to 0.8 percent of a total mixed diet and 1.2 to 1.6 percent of a concentrate mixture magnesium oxide should be added @ 0.2 to 0.4 per cent of total mixed diet or 0.4 to 0.6 percent of a concentrate mixture. When feeding a combination of two, 2 to 3 parts NaHCO3 should be mixed with one part Mg O. Feeding large amounts of these mineral salts may depress feed intake

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  • Antioxidants

    Antioxidants are chemical compounds which have the capacity of preventing oxidation of substance by taking up oxygen High fat vegetable products (oils/fat), tallow, lard, fish meal and poultry by product meal are more prone to oxidative rancidity. This imparts off flavours which reduces voluntary feed intake and bioavailability of amino acids and fat soluble vitamins like vitamin A and vitamin E. Commonly used antioxidants are butylated hydroxyl anisole (BHA), butylated hydroxy toluene (BHT) and ethoxyquin. The natural antioxidants include vitamin E, vitamin C and rosemary. These are added directly into the mixed feed, feed ingredients and vitamin premixes @125 to 200g/tonne of feed. Synthetic antioxidants are comparatively cheaper and long lasting.

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  • Prebiotics/Oligosaccharides

    Non digestive feed ingredients selectively stimulate growth and/or activity of limited number of bacterial species already resident in the digestive tract and thus improves host health

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  • The oligosaccharides are water soluble carbohydrates consisting of 2 to 10 monomeric unitsThey resist attack by the digestive enzymes of humans and animals and therefore not metabolized directly by the host They reach colon directly and interact with the microbial flora act as specific growth substrates and alter cell adhesion and immuno modulationWhen used in mixed amounts in feed (below 1%) oligosaccharides increases weight gain and improves health statusEffects vary as per type of oligosaccharide employed, the class of animal, its age, animal species and management conditionsA wide variety of oligosaccharides (fructo-, gluco- and glacto-oligosacchrides) is commercially available as feed additives

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  • ADVANTAGES Most are natural products, made of very simple sugars, without any antigenic capacityThey do not present side effect or accumulate in animal tissuesThey are resistant to change in pH or temperatureThey do not have viability problems like probiotics and enzymes. To date, the use of oligosaccharides has been limited due to the difficulty in obtaining clearly reproducible results

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  • Plant extractsSarsaponin, a naturally occurring steroid saponin contained in yucca schidigera plant extrac

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