What are the commonly used feed additives in animal nutrition?
In order to promote animal growth and maintain health, health-care and non-nutritive additives are often added to the feed.
Antibiotics are metabolites of microorganisms. It can stimulate the reproduction of bacteria that synthesize known or unknown nutrients, inhibit the microorganisms that compete with the host for nutrients, and improve the absorption capacity of the intestinal tract. Therefore, antibiotics can not only enhance disease resistance, but also have the effect of promoting growth.
Feed antibiotics can be divided into two categories: one is the antibiotics shared by humans and animals, such as penicillin, tetracycline, oxytetracycline, chlortetracycline, streptomycin and kanamycin; the other is the antibiotics dedicated to livestock and poultry, such as bacillus Peptide zinc, virginiamycin, tylosin, beilimycin, etc.
Oxytetracycline is a tetracycline antibiotic, and the growth-promoting feed additive approved by the Ministry of Agriculture of my country is oxytetracycline calcium salt. Oxytetracycline is a widely used antibiotic with broad antibacterial spectrum and is effective against most gram-positive bacteria and some gram-negative bacteria. Oxytetracycline is less toxic, but there are residues, and many bacteria are prone to resistance to it. The dosage is: 5 × 10-6 to 7.5 × 10-6 when used as a growth-promoting agent, and it is forbidden for laying birds. The withdrawal period was 1 week before slaughter. Note that oxytetracycline and olaquindox have antagonistic effects.
The antibacterial spectrum of bacitracin zinc is similar to that of penicillin, and it is very effective against gram-positive bacteria, as well as some gram-negative bacteria, spirochetes, and actinomycetes.
It is highly efficient and low in toxicity and hardly produces drug resistance. Due to its large molecular size, it is generally not digested and absorbed by animals, and will not cause residues in the body, so it is safe to use. Bacitracin zinc is specially used for livestock and poultry, so it has been widely used for many years, and the addition amount is 4 × 10-6 to 4 × 10-5. Note that bacitracin zinc should not be mixed with polyether antibiotics such as monensin and salinomycin.
Virginiamycin has not yet been produced in my country, and has been approved for import into the United States. It has the functions of promoting growth and improving feed utilization. The addition amount is 1×10-5 to 2×10-5.
Beilimycin is a macrolide antibiotic with broad antibacterial spectrum and low residues. It is a safe and efficient growth-promoting antibiotic. my country has not yet been able to produce it, and Kitarimycin is used for feed, and it has been approved to import Japanese products. For promoting growth, the addition amount is 5.5×10-6～1.1×10-5; For treating diseases and health care, the addition amount is 1.1×10-4～3.3×10-4. But note that it can only be used for 5 to 7 days in a row. It is forbidden for egg-laying birds, and the withdrawal period is 2 days before slaughter.
Tylosin is a macrolide antibiotic. The commonly used feed additive is the phosphate of tylosin, and the titer is the same as that of tylosin. my country has not yet produced it, and it has been approved to import American products. Tylosin has a broad antibacterial spectrum, low toxicity, and is safe and stable. Dosage: 4 × 10-6 to 5 × 10-5 for poultry (within 8 weeks), drug withdrawal 5 days before slaughter.
Probiotics used to be called competitive biotin, also known as live bacteria, probiotics or probiotics. Its function is mainly to make up for the lack of beneficial bacteria in the animal digestive tract, competitively reject pathogenic microorganisms; change the metabolites in the digestive tract, reduce or eliminate the production of harmful substances; produce enzymes and other growth-promoting substances; produce antibodies and improve phage activity. , to stimulate the immune system of animals, improve low resistance. In the environment of intensive feeding and feeding and management conditions, the effect of using probiotics is very obvious. The use of probiotics can avoid the disadvantages of drug resistance and residue caused by long-term use of antibiotics.
One type of probiotic bacteria is aerobic bacteria, such as Bacillus cereus isolated from soil, Bacillus subtilis and tempeh isolated from subtilis, and Lactobacillus that produces aerobic spores; the other is anaerobic bacteria Sexual bacteria, such as butyric acid bacteria, Lactococcus, Lactobacillus nonspores, etc. The probiotic preparations that have been developed and produced in my country include "prebiotic source", "promoting bacterial growth", "regulating dysentery", HB-1 enrichment and so on.
Enzyme preparations are mainly used in young animals to make up for the lack of digestive enzyme secretion and improve the digestibility of nutrients; for adult animals, to improve digestive function and make up for the decrease in digestive enzyme secretion due to stress and other reasons. Commonly used enzyme preparations mainly include protease, amylase, cellulase, lipase, β-glucanase, phytase and pectinase.
Arsenic Preparations Arsenic is both an essential element for animals and a toxic element. Organoarsenic preparations act as growth promoters for chicks similar to antibiotics. Arsenic preparations used as growth promoters include p-aminophenylarsenic acid, 3-nitro-4-hydroxyphenylarsenic acid, and the like. The addition amount of p-aminophenylarsenic acid is 0.01% to 0.02%, and the addition amount of 3-nitro-4-hydroxyphenylarsenic acid is 3.7×10-5 to 5×10-5.
Since the use of sex hormones (steroid compounds) has side effects, most countries have banned such hormone preparations from the perspective of safety. However, because hormones or hormone substances have a strong effect of stimulating growth and can bring considerable economic benefits, people have always attached great importance to the development of new hormone products, such as growth hormone, which can be mass-produced using genetic engineering technology. Although the use of growth hormone is still controversial, the safety of growth hormone is better than that of other small molecule hormones, and its growth-promoting effect is very obvious.
Beta-stimulants are a class of amines with a chemical structure similar to epinephrine, which have the effect of promoting animal growth, especially promoting the redistribution of animal nutrition, improving protein synthesis and carcass lean meat rate. It has been reported that β-stimulants can increase weight gain, feed conversion rate and lean meat rate in poultry. Insect repellent health care agent
At present, the most widely used anthelmintic health care agents are anticoccidial agents, which can be divided into two categories: chemical synthesis agents and antibiotics.
Amproline is a sulfonamide derivative, which is a chemically synthesized anticoccidial agent with the highest safety and widest application. As the feed additive, amprolium hydrochloride, its ethoxyn amidine, and sulfaquinoxaline are composed of two or three mixtures. The mechanism of action of amprolium is to replace thiamine in the metabolism of coccidia, and it is widely used to control avian coccidiosis. Amproline is approved in the United States for both breeders and as the only anticoccidial drug that can be used for laying hens. It has low toxicity and no withdrawal period requirements. The preventive dose is 6.25×10-5～1.25×10-4 mixed with compound additives or feed. However, it should be noted that choline chloride is hygroscopic and will promote the decomposition of amproline. In addition, aminoproline is structurally similar to vitamin B1, and both have antagonistic effects.
Clohydroxypyridine, also known as chloropyridine, chlorocresol, etc., with trade names such as Keqiufen and Kawaidan, is an anti-coccidial additive with low toxicity, safe use and wide application. The effect of this product in inhibiting coccidiosis is more obvious than that in killing coccidiostat. The amount added to the feed is 6×10-5 to 8×10-5.
Probenazine, also known as diclofenac and robenazine, is a commonly used anticoccidial drug, which has a good effect on avian coccidiogenesis, and has the effect of improving weight gain and feed utilization. This product is less toxic and safe to use. The amount added to the feed is 3.3×10-5, which can be increased to 6.6×10-5 if used for treatment. Due to the odor of chloride, the use of the therapeutic dose can lead to residual odor in meat and eggs. Therefore, after 1 to 2 weeks of high-dose treatment of avian coccidiosis, the preventive dose should be changed to reduce Dosage. The drug should be discontinued 5 to 7 days before the market for meat and poultry, and it is forbidden for egg-laying poultry.
Salinomycin sodium, also known as salinomycin and salinomycin sodium, is a polyether antibiotic. It has inhibitory effect on most gram-positive bacteria and avian coccidia. It has no cross-resistance with anti-coccidial agents such as amproline, clodipidine, clobenil, and monensin. The amount added to poultry feed is 5 × 10-5 to 7 × 10-5, and the drug is discontinued 5 days before slaughtering, and egg-laying birds are prohibited. Salinomycin sodium can be used together with other antibiotics, but not with troleandomycin and tylosin to avoid poisoning such as foot paralysis.
Monensin sodium, also known as rumenin, is a polyether antibiotic. It has inhibitory effect on fowl coccidia. The dosage is 9×10-5～1.1×10-4. The medicine should be stopped 3 days before the slaughter of meat and poultry, and it is forbidden for egg-laying poultry. Monensin sodium cannot be used together with troleandomycin and tylosin to avoid poisoning.
The trade name of Hainanmycin is chicken ball, which is a unique antibiotic for polyether animals in my country. Hainanmycin has inhibitory effects on coccidia and gram-positive bacteria, and is still effective against coccidia that have developed resistance to other anticoccidial drugs. The dosage of chicken coccine (premix containing 1% Hainanmycin) in meat poultry feed is 5 × 10-6 to 7.5 × 10-4. The drug should be discontinued 3 to 5 days before slaughter, and it is forbidden for egg-laying birds.
feed flavoring agent
Flavoring agents are a kind of chemical substances that can make animals have a good taste. There are many kinds of commercial flavoring agents. The most commonly used flavoring agents used as feed additives are: sweeteners that increase the sweetness of feeds, such as sodium saccharin; sour agents that adjust the acidity of feeds, such as citric acid, lactic acid, tartaric acid, etc.; umami agents that increase the umami taste of feeds, such as sodium glutamate.