Feed Additives

Pages 319 – 325 (Chapter 6)

Why use them? • Cause a desired response/benefit– Alter metabolism– affect growth– change pH– manipulate microflora– improve digestion– increase yield– Reduce acidosis– Improve immune response– Increase palatability– Reduce fecal odor– Reduce joint pain

Major Classes• Growth Promotion and Feed Efficiency

– Antibiotics• Medicinal Uses

– Coccidiostats, worming agents• Others

– Buffers and Neutralizers– Antioxidants– Preservatives– Binders– Direct Fed Microbials– Coloring Agents– Flavorings

• Hormonelike products– Feed Additives– Implants

Examples

• Antibiotics: disease prevention• Coccidiostats: control parasites• Xanthophyll: makes egg yolks yellow– Cantaxanthin

• Hormones (hormone like): increases growth• Yeast, Fungi, Direct fed microbials: • Buffers: HCO3 etc.. Prevent rumen acidosis• Antioxidants: prevents feed from getting rancid• Pellet Binders: keeps feed in pellet form• Flavoring Agents: makes feed taste better• Surfactants: lipid digestion, increase milk production, yield• Anionic salts: acidify diet to increase Ca absorption

FEED ADDITIVES• Use of feed additives is strictly regulated in the

developed countries, and many others, to ensure:– Human food safety– Animal safety– Additive efficacy– Minimal environmental impact

• Dramatic increase in globalization of marketingof animal products has led to more uniformity in regulations among countries.– Animal products must comply with the laws of

the countries to which they are being sold.

FEED ADDITIVES• AAFCO (Association of American Feed Control

Officials) provides the U.S. mechanism for developing/implementing uniform & equitable laws, regulations, standards, and enforcement policies.– Regulating manufacture, distribution, and sale of

safe and effective animal feeds.

• AAFCO defines a feed additive as… – "an ingredient or combination of ingredients added

to the basic feed mix …to fulfill a specific need."

– " …usually used in micro quantities and requirescareful handling and mixing"

FEED ADDITIVES

• In practice, feed additives are defined as feed ingredients of a nonnutritive nature that…– Stimulate growth or other types of performance.– Improve the efficiency of feed utilization.– Are beneficial in some manner to health or

metabolism of the animal.

FEED ADDITIVES• Of the groups of additives classed as drugs, the major

groups include many different compounds:– Antibiotics, nitrofurans and sulfa compounds.– Coccidiostats, wormers (antihelminthics & others),

and hormone-like compounds.

• Feed additives have been used extensively in the U.S. and many other countries since the discovery & commercial production of antibiotics and sulfa drugs in the late 1940s. – The European Union recently banned feeding of antibiotics

to animals meant for human consumption.

FEED ADDITIVES• Animal products are routinely tested to ensure

that feed additives are being used correctly. – Use of feed additives has been beneficial to livestock

producers under our modern methods of production. • Development of intense systems of management

and concentration of animals has been made possible only because additives could be used to help control various diseases and/or parasites.– Broilers, laying hens, growing-finishing pigs, and

fattening cattle and sheep.

ADDITIVES CLASSED AS DRUGS

• In the U.S., use & regulation of additives classed as drugs is controlled by the Center for Veterinary Medicine, within the FDA.– To determine that drugs & medicated feed are

properly labeled for intended use and that animal feeds and food derived from animals are safe to eat.

• Federal law states no animal drug can be usedin feed until adequate research submitted to the FDA proves the drug is both safe and effective. – In developing a new drug for use with animals,

manufacturers must go through extensive testing.

ADDITIVES CLASSED AS DRUGS Requirements for Medicated Feed

• FDA requirements for medicated feed focus on mixers who use human-risk drug sources. – Mixers who do not use human-risk drug sources

are subject to less demanding regulation.

ADDITIVES CLASSED AS DRUGS Antibiotics

• Antibiotics are compounds produced by microorganisms.– inhibit growth/metabolism of some (not all) other

microorganisms.– In some instances, they may be toxic to warm-

blooded animals. – Most antibiotic names end in -cin or -mycin.

• All antibiotics used commercially for growth promotion are produced by fermentation processes using fungi or bacteria.

ADDITIVES CLASSED AS DRUGS Antibiotics

• Antibiotics are effective at improving production when fed at low levels to young, growing animals.

ADDITIVES CLASSED AS DRUGS Antibiotics

• Improve feed efficiency.

– Growth is nearly always increased, particularly with animals exposed to adverse environmental conditions.

– Feed intake usually decreases in ruminants.

– Varies by animal species. – Antibiotic-fed animals are less apt to go off feed. – Can control a wide variety of diseases. – As a rule, reduce the incidence or severity of several types

of diarrhea

ADDITIVES CLASSED AS DRUGS Antibiotics

• Some are approved at low levels of continuous use for reducing the incidence of… – Enterotoxemia (overeating disease) in lambs.– Liver abscesses in fattening cattle.– Diarrhea in young mammals deprived of colostrum.

• In poultry, some claims include…– Reduction in respiratory disease.

– Nonspecific enteritis (blue comb) & infectious sinusitis.– Improved egg production and hatchability.

ADDITIVES CLASSED AS DRUGS Antibiotics

• At higher levels for therapeutic treatments, antibiotics have been very useful for…– Cattle - treating or preventing stresses associated with

transportation and adjustment to new conditions.

– Treatment of diseases such as anaplasmosis in cattle and bacterial enteritis in swine.

– Respiratory diseases, diarrhea, fowl cholera, fowl typhoid, and breast blisters in poultry.

• In most instances, the higher levels are not approved for long-term additive feeding usage.

ADDITIVES CLASSED AS DRUGS Antibiotics

• Two antibiotics for use in cattle, monensin and lasalocid, are unusual in that they give a good response in both growing and mature animals.

– Approval was first received for use as coccidiostats with poultry.

– Both of these antibiotics are quite toxic to horses.

ADDITIVES CLASSED AS DRUGS Antibiotics

• Obtaining approval for new feed additive drugs has become more difficult in recent years. – More investigative effort & expense are involved.– As a result, not many new additives have been approved in

recent years.

• Very few antibiotic additives are approved for horses, rabbits, sheep, goats, ducks, pheasants & quail. – No approvals are given for geese, dogs, cats, exotics.

• The primary reason is the cost of obtaining approval in relation to potential sales volumes.

ADDITIVES CLASSED AS DRUGS Antibiotics

• In poultry, the trend is to use one or more antibiotics in nearly all broiler feeds.– Most can be used for layers, except high levels

of chlortetracycline and erythromycin.

• Manufacturer approval must be obtained forusing different combinations of antibiotics.– Or combinations of antibiotics & other controlled drugs.

• Far more drug combinations have been approved for chickens & turkeys than all other animals combined.

– It is illegal to feed antibiotics at different levels or in different combinations from those previously approved.

CLASSED AS DRUGS Arsenicals

• Arsenicals are all synthetic compounds (chemotherapeutic agent) & include a number of drugs used in turkey, chicken, and swine rations.– Developed as a means of controlling parasites.– Some compounds stimulate growth in the same

manner as antibiotics.– The effect can be additive to antibiotic stimulation.

• Several arsenicals have claims of improved growth production as well as improved feed efficiency for chickens, turkeys, or swine.– And control of blackhead in poultry & diarrhea in

swine.

ADDITIVES CLASSED AS DRUGS Arsenicals

• Arsenicals have the disadvantage that they may accumulate in body tissues, particularly the liver. – At the levels fed, they are not considered to be toxic.

– All have a minimum 5-day withdrawal period before animals are to be slaughtered for human food.

ADDITIVES CLASSED AS DRUGS Coccidiostats

• Coccidia are microscopic parasites.– Coccidiostats include a wide variety of compounds,

ranging from a number of synthetic drugs to severalof the antibiotics.

• These drugs are of considerable importance to the poultry producer because close confinement methods used in modern facilities accentuate the possibility of coccidiosis outbreaks. – Evidence suggests coccidiosis is becoming a greater

problem with sheep & cattle in close confinement.

ADDITIVES CLASSED AS DRUGS Nitrofurans

• The nitrofurans are antibacterial compounds and are effective against a relatively large number of microbial diseases. – Continued use of nitrofurans has not as yet

developed bacterial resistance, as is thecase for some antibiotics.

ADDITIVES CLASSED AS DRUGS Sulfas

• Reduction in use– Problems with tissue residues

• Most of problems alleviated by sulfas can be managed with other additives.

ADDITIVES CLASSED AS DRUGS Hormone-like Production Improvers

• Melengestrol acetate (MGA) is the only hormone-like production improver remaining on the approved list.– Extensively used with beef heifers; it acts to

suppress estrus, resulting in more efficient and more rapid gain.

ADDITIVES CLASSED AS DRUGS Hormone-like Production Improvers• Although not feed additives, several products

are available for use as subcutaneous implants. – Hexestrol, (outside the U.S.)– Zeranol (Ralgro™), said to be an anabolic agent.

– Synovex™, a combination of estrogen & progesterone.

– Rapid Gain™, a combination of testosterone & estrogen

– Steer-oid™, a combination of progesterone and estradiol.

• A high percentage of growing- finishing cattle are treated with one or another of these implants.

ADDITIVES CLASSED AS DRUGS Hormone-like Production Improvers

• In ruminants, natural or synthetic hormones produce a response that results from increased nitrogen retention accompanied by an increased intake of feed. – Increased growth rate; Improvement in feed

efficiency.

– Reduced deposition of body fat, which may, at times, result in a lower carcass grade for animals fed to the same weight as nontreated animals.

• Molecules that structurally resemble epinephrine– Caffeine, ephedrine, aspirin

• Easily made in the lab• Muscle: – Increase in muscle synthesis– Decrease in muscle breakdown

• Fat– Decrease in lipogenesis– Increase in lipolysis

• Ractopamine (Paylean)

-agonists

Agonist summary

• Structurally resembles epinephrine• Increases muscle synthesis– Need to increase the protein % of diet

• Decreases fat content• Orally active• Desensitization• Recently approved for pigs and beef cattle

Antioxidants• Used to prevent rancidity of unsaturated fatty

acids• Inclusion rates up to 0.25 Lb per ton• BHA/BHT (Butylated hydroxyanisole or

toluene)• Ethyoxiquin • Vitamin E • Rosemary

Preservatives• Used to prevent feed deterioration

(mold/bacteria inhibitors)– Vitamin C– Calcium sorbate– Citric acid – Phosphoric acid– Propylene glycol (toxic in cats)– Sodium propionate– Sodium metabisulfate

Buffers and Neutralizers

– Buffers & Neutralizers• Lessen the decrease in pH caused by VFA production• Valuable for use in high concentrate diets to ruminants

but not high forage diets• Examples

– Sodium bicarbonate (most effective and most common)– Potassium bicarbonate– Calcium carbonate– Mag oxide– Mag carbonate

DFMs and Yeastwww.microbialcompendium.com

– Bacteria, Enzymes, Mold, Oligosaccharides, Yeast– Lactobacillus, streptococcus, fungi, aspergillus, bacillus – Probiotics

• Scientifically inconsistent• Consist of microbial cultures

– Can stimulate cultural growth• Reasons for use

– Increase/balance beneficial bacteria– Reduce toxic byproducts of digestion– Support rate of gain and feed efficiency– Alleviate/minimize stress

• Various times for use– When do you use them?

• Available forms– Feed additives– Water dispensing– Bolus/gel form

• Aspergillus niger• Aspergillus oryzae• Bacillus coagulans• Bacillus lentus• Bacillus licheniformis• Bacillus pumilus• Bacillus subtilis• Bacteroides amylophilus• Bacteroides capillosus• Bacteroides ruminocola• Bacteroides suis• Bifidobacterium adolescentis• Bifidobacterium animalis• Bifidobacterium bifidum• Bifidobacterium infantis• Bifidobacterium longum• Bifidobacterium thermophilum

• *Enterococcus cremoris• *Enterococcus diacetylactis• *Enterococcus faecium• *Enterococcus intermedius• *Enterococcus lactis• *Enterococcus thermophilus• Yeast• Aspergillus niger• Leuconostoc mesenteroides• Pediococcus acidilacticii• Pediococcus cerevisiae (damnosus)• Pediococcus pentosaceus• Propionibacterium acidpropionici

(cattle only)• Propionibacterium freudenreichii• Propionibacterium shermanii• Saccharomyces cerevisiae• *Enterococcus cremoris• *Enterococcus diacetylactis• *Enterococcus faecium• *Enterococcus intermedius• *Enterococcus lactis• *Enterococcus thermophilus• Yeast

• Lactobacillus acidophilus• Lactobacillus brevis• Lactobacillus buchneri (cattle only)• Lactobacillus bulgaricus• Lactobacillus casei• Lactobacillus cellobiosus• Lactobacillus curvatus• Lactobacillus delbruekii• Lactobacillus farciminis (swine only)• Lactobacillus fermentum• Lactobacillus helveticus• Lactobacillus lactis• Lactobacillus plantarum• Lactobacillus reuterii• Leuconostoc mesenteroides• Pediococcus acidilacticii• Pediococcus cerevisiae (damnosus)• Pediococcus pentosaceus• Propionibacterium acidpropionici

(cattle only)• Propionibacterium freudenreichii• Propionibacterium shermanii• Saccharomyces cerevisiae

Microorganisms found to be appropriate for use n animal feeds

Pet Food• Pet food, including dry and canned food and pet treats, is considered to be animal feed. Like other animal feed, FDA regulates pet food and establishes standards for labeling.

• Pet food labeling is regulated at two levels: federal and state. The federal regulations, enforced by FDA’s Center for Veterinary Medicine, establish standards that apply to all animal feeds:– proper identification of the product– net quantity statement– manufacturer’s address– proper listing of ingredients

• FDA carries out its animal feed regulatory responsibilities in cooperation with state and local partners, and works together with AAFCO on uniform feed ingredient definitions and proper labeling.

Lab Assignment

• Find a research article (journals only) – additive

• Cite the study • Indicate species, number animals used,

treatments (doses/inclusion rates)• Intended benefit• Outcome