Type of drug

Salinomycin

Anti-coccidiosis, promote growth, use the same monensin, have a strong inhibitory effect on asexual schizonts, combined with anti-coccidiosis drug synergist ethoxyamide benzyl, the treatment effect of coccidiosis is better Good, but more toxic than the latter. The drug has a narrow safety range. If the concentration is too high or the use time is too long, side effects such as decreased feed intake, weight loss, ataxia, and leg weakness may occur. Slightly more toxic, 60 mg per kilogram of feed for poultry.

Lasamectin

It is a divalent polyether antibiotic, which is the least toxic in this class of drugs. It can be used in combination with tiamulin. However, due to the influence of the drug on the metabolism of divalent cations, it is easy to cause an increase in the host's water excretion, so when a larger dose is used , The litter is easy to wet. Mixed feeding is 7.5 grams to 12.5 grams per 100 kilograms of feed.

Naramectin (Methylsalinomycin)

The action spectrum and compatibility contraindications are similar to those of salinomycin, but the toxicity is stronger than the latter. Compatible and combined with Nicarbazine, the effect is better. Mixed feeding is 6 to 8 grams per 100 kilograms of feed, and is only used for broilers.

Maduramycin

The mechanism of action is similar to monensin, but it acts on coccidia that are resistant to other polyether antibiotics, especially duck coccidia. It is more toxic than other drugs and has a narrower safety range. It is only used for broilers and has no cross-resistance with other chemically synthesized anticoccidial drugs. Mixed feeding is 0.5 g per 100 kg of feed.

Hainanmycin

It is an original polyether anticoccidial drug in my country, but its toxicity is the most toxic of this class of drugs. It is limited to broiler chickens. It is contraindicated with other anticoccidial drugs. Mixed feeding is 0.50 g ~ 0.75 per 100 kg of feed. Grams. Saidumycin, phleomycin, ronomycin, etc. are also included in this class of drugs, which all have the effect of preventing coccidiosis.

Drugs with preventive and therapeutic significance

This class of drugs does not affect the host's immunity. It acts on the first and second generation schizonts of coccidia. Some have a therapeutic effect greater than a preventive effect. They can be used in laying hens and broiler breeders in poultry. Such drugs mainly include triazines, dinitros, and sulfa drugs.

Triazines

Diclazuril: Also known as chlorazine phenethyl cyanide, its anti-coccidial effect is better than that of polyether drugs and other anti-coccidial drugs that act on the first generation of schizonts. It has the characteristics of high efficiency and low toxicity and is a typical ideal anticoccidial drug. Parasite drugs. The disadvantage of this medicine is that it has a short half-life and requires continuous medication, but it is prone to drug resistance. Mixed drinking is 0.05 grams to 0.1 grams per liter of water, and mixed feeding is 0.1 grams per 100 kilograms of feed. If it is used in combination with Chinese medicine, the effect will be better.

Toltrazuril: also known as triazinone and diazepam. It has a broad anti-coccidial spectrum and can act on all stages of coccidia development. It also has a good effect on coccidia resistant to other coccidia drugs, and is toxic. It is lower, and there is still no danger to animals when the dose is 10 times. It remains in the edible tissues of broilers for a long time. Continuous medication is prone to drug resistance. Mixed drinking: Chicken 25 mg per liter of water.

Dinitros

Dinitramine: also known as qiuliling, with a broad spectrum of action, has an effect on a variety of coccidia, and does not affect the host immunity. It is suitable for laying hens and broiler breeders, and is forbidden during the laying period. It has cross-resistance with nitrofuran drugs. Sugars should not be used as excipients for this type of drugs, as they can easily change the color of sugars. Mixed feeding is 12.5 grams per 100 kilograms of feed.

Nicarbazine: Acts on the second-generation schizonts of coccidia, does not affect the host's immunity, is suitable for laying hens and broiler breeders, and is forbidden during the laying period. Coccidia develop resistance to this class of drugs slowly; this class of drugs should not use sugars as excipients, which can easily change the color of sugars. It is forbidden during the laying period, and used with caution in the hot season. Mixed feeding is 12.5 grams per 100 kilograms of feed.

Sulfonamides

Sulfaquinoxaline: It is a special sulfa drug for coccidia. The mechanism is mainly to interfere with the metabolism of folic acid and inhibit its growth and reproduction. It is not suitable for long-term use, especially for livestock and poultry with kidney disease. It is often used in combination with amproline to expand resistance. Insect spectrum. Mixed drinking is 12.5 grams per liter of water, and mixed feeding is 25 grams per 100 kilograms of feed. It cannot be used continuously for a long time.

Sulfachloropyrazine: It is a special sulfa drug for anti-coccidiosis. This medicine is the main component of three-character coccidia powder commonly used in the market. It is used with symptomatic treatment drugs for Anluo Xue or vitamin K3 to treat coccidiosis outbreaks in livestock and poultry. This medicine also has a strong antibacterial effect and can be used to treat fowl cholera and chicken typhoid fever. Mixed drinking 30 grams per liter of water, mixed feeding 60 grams per 100 kilograms of feed, continuous use for 3 days.

Sulfamethazine: This medicine can be used for both coccidial infections and bacterial infections. It is suitable for the treatment of coccidial and bacterial mixed infections. Such as the treatment of mixed infections of E. coli and coccidia. Mixed drink 100g～150g per liter of water, mixed feed 200g～300g per 100kg of feed, used for 3 days, stop for 2 days, and then continue to use the medicine for 3 days. When kidney disease occurs, it is better to use baking soda together.

Sulfamonomethoxine: 30 grams per liter of water for mixed drinking, 30 to 50 grams per 100 kg of feed for mixed feeding, for 3 days.

Coccidiosis is a widespread protozoal disease. Due to its important impact on the poultry industry, the majority of scientists have been seeking effective methods to control this disease for decades. Drug therapy, immunization and combination therapy have been widely used. The summary is summarized as follows, so that the majority of poultry farmers can learn from when choosing control strategies.

Drug therapy

Drug therapy is recognized as an effective method for preventing and treating coccidiosis, that is, using anticoccidial drugs as a feed additive[1～4].

Mode of action

1.1.1 "Drugs acting on cell membranes

Polyether antibiotics are a class of anticoccidial drugs that have been put on the market in the 1970s. Since 1985, my country has been popularized and applied, mainly including monensin, salinomycin, methyl salinomycin, lasalocid and maduramycin. Polyether antibiotics can penetrate the cell membrane to affect the transport of ions. These drugs are absorbed before the sporozoites or merozoites penetrate the host cell, combine with the ions in the coccidia and form complexes, disrupting the normal ion balance of the cell , Leading to coccidia metabolism disorder and death. At the same time, activating Na+-K+-ATPase increases the consumption of ATP, the production of lactic acid, and the consumption of amylopectin [5]. Its peak period of action is during the coccidian invasion period, which is effective for sporozoites and the first generation merozoites outside the cell.

1.1.2 "Drugs that affect the absorption and synthesis of coenzymes

As preventive drugs to control coccidiosis, sulfa and amproline were once widely used. Sulfonamides inhibit the formation of dihydrofolate by competing with p-aminobenzoic acid for dihydrofolate synthase, thereby inhibiting the normal development of coccidia, and are most effective against the second generation merozoites of all coccidia. Amprolium replaces thiamine during the metabolism of coccidia, so that many carbohydrate metabolism reactions involving thiamine cannot proceed, thereby inhibiting the development of coccidia. Its highest activity is on the 3rd day of the cycle, which is the most effective for the first generation of merozoites, and it also has a certain effect on the sexual cycle and sporozoites.

1.1.3 Drugs that affect mitochondrial function

Quinoline and pyridine anticoccidial drugs were used to control coccidiosis in the 1970s, and their application has declined due to the rapid emergence of drug resistance. They all inhibit the respiration of coccidia by blocking electron transport in mitochondria, making them unable to develop, but their modes of action are different. The highest active period of these two types of compounds is the first day of the life cycle of the coccidia, that is, the sporozoite stage. They only inhibit the development of sporozoites and cannot kill the coccidia. The active ingredients of Chlorpheniramine and Nicarbazine have the ability to bind to proteins, which prevents mitochondria from coupling and inhibits the process of oxidative phosphorylation, but the true mechanism of action on coccidia is still unclear. The highest active period of chlorphenidine against Eimeria tenella is on the second day of its life cycle. Nicarbazine’s anti-coccidial activity period is the second generation merozoites of the coccidian life cycle, which kills coccidia. The effect is greater than the inhibitory effect.

1.1.4 Drugs acting on plastids

Triazinone is a new broad-spectrum anticoccidial drug that can inhibit the function of D1 protein, thereby affecting the electron transport at low oxygen concentrations or the invasion of coccidia on host cells. Studies have shown that triazone can swell the endoplasmic reticulum, mitochondria and other membranous structures of the coccidia at various developmental stages, resulting in severe vacuolar degeneration, and its active cycle is longer.

1.1.5 Other anticoccidial drugs

Changshanone, also known as Sudan, has high coccidia-killing activity and has an effect on the three stages of coccidia development. Dinitramine, also known as qililing, mainly inhibits the asexual reproductive phase of the coccidial life cycle, that is, the third day of the cycle. Shaqiuling is a new type of anticoccidial drug with high efficiency, broad spectrum and low toxicity. However, there are few reports on the mechanism of action of these drugs. The application of artemisinin, artemisinin-TMP mixture, "Quqiu San", "Di Mo Decoction" and other Chinese herbal medicines and Chinese herbal medicine preparations have also made great progress in the prevention and treatment of this disease. Research has shown that Chinese herbal medicines and their preparations are used to prevent and treat this disease. Coccidiosis is safe, reliable, highly effective, has no drug residues, and can regulate the body's immune function. It is a promising method.

Problems and Solutions

In the process of applying drugs to control coccidiosis, some drug-resistant strains continue to appear. Some data indicate [6-8] that almost all anticoccidial drugs are threatened by drug-resistant strains to varying degrees, and exhibit a certain degree of cross-resistance. The emergence of drug-resistant strains often makes the prevention and control of coccidiosis a failure. In severe cases, coccidiosis still occurs under the condition of medication, bloody stools and death occur. In fact, more cases are caused by decreased weight gain and feed after the decline in drug efficacy. The conversion rate is reduced, causing considerable economic losses to the poultry farmers. In order to reduce or delay the development of drug resistance and maintain the effectiveness of anticoccidial drugs, people often adopt medication regimens such as rotation medication, shuttle medication, and combined medication. Rotation is the continuous application of a certain medicine within a certain period of time, and then switching to another medicine to avoid drug resistance caused by long-term use of the medicine. Shuttle medication refers to the administration of different anticoccidial drugs at each growth stage of chickens. Nicarbazine is the commonly used drug in the first phase of this program. Combination of drugs refers to the combined use of two or more anticoccidial drugs with different activities, and the use of their synergistic effect to expand the anticoccidial spectrum and improve the efficacy. Increasing the drug concentration may be effective for a certain period of time, but it is not ideal from the economic point of view and drug residue considerations.

Another problem in chemotherapy is the suppression of immunity. The phasic development of coccidia is relatively obvious, and only when it develops to the second-generation mesozoic reproductive stage does it release functional antigens to induce the production of immunity. However, the peak period of activity of most anticoccidial drugs is in the asexual reproduction stage of coccidia development, which may prevent the coccidia from developing to the second-generation schizophrenia stage, thus failing to induce immunity. For this reason, it is necessary to limit the amount of medicine in the feed, so that the chicks can maintain a certain degree of infection without getting sick, and part of the oocysts will develop in the surrounding of the medicine to induce the production of immunity. This method is more suitable for laying chickens and breeding chickens.

Precautions

In order to prolong the effectiveness of the drug, the long-term single use of an anticoccidial drug should be avoided. Different medication regimens should be adopted for different flocks and different feeding conditions. For broilers, continuous medication is necessary to prevent the occurrence of coccidiosis. In laying hens and breeders, on the one hand, it is necessary to prevent the outbreak of coccidiosis, on the other hand, to make the chickens have anti-coccidiosis immunity, so the medicine is generally only used before laying eggs. Moreover, it is best not to affect the production of immunity by these drugs, such as gallyl, nicabazine and so on. The method of medication is different for different feeding conditions. From flat rearing to net rearing, use a regular amount of anticoccidial medicine when rearing on the net, and you don't need to use the medicine when you go online. From flat rearing to flat rearing, use the appropriate level of anticoccidial drugs in the chicks to reduce the number of oocysts and enable the chickens to obtain a certain level of immunity. When moving to a new house, it is best to use a new litter to prevent the contamination of worms in the litter of adult chickens. Generally, the disease will not occur without medicine in the later period.

The drug should be used rationally according to the peak period of action of the drug. This includes two aspects of prevention and treatment. When choosing a preventive medication plan, the drug should be properly prepared according to the peak period of action of the drug. For example, amproline is active on E.tenella and E.necatrix, but has partial activity on E.maxima; B Oxamide benzyl is active against E.acervulina and E.mivati. After the two are used in combination, their anti-coccidial spectrum is greatly expanded and the therapeutic effect is also significantly improved. On the other hand, when coccidiosis occurs, the corresponding drugs in the peak period of action should be selected according to the time of onset to obtain the best therapeutic effect.

When adopting a drug rotation and a shuttle drug regimen, the order of use of these drugs must be determined according to the mode of action and characteristics of the drugs, and the use of two drugs with the same mode of action should be avoided. For example, in the first few weeks of broilers, it is unwise to use coccidiosis drugs first and then ionophore drugs because the endogenous development period inhibited by coccidiosis drugs is not affected by the subsequent use of ionophores drugs. , The endogenous developmental period can still develop. In addition, it is unreasonable to use anticoccidial drugs in the final stage of a batch of broiler chickens. Because the coccidia inhibited by the drug may develop within 5-7 days of drug withdrawal.

It is necessary to ensure that the coccidiosis can be controlled at the most critical moment, which must ensure that the drug with the strongest anti-coccidiosis effect is available at this moment. Therefore, according to the epidemiology of coccidiosis and the effectiveness of the drugs, the medication plan should be adjusted in time to make the use time of the most effective anticoccidial drug consistent with the most dangerous period of possible coccidiosis infestation.

Attention should be paid to drug residue issues. Since anticoccidial drugs are generally used for a long time, residues in meat and eggs are inevitable, which often affect the quality of products and people's health. Therefore, it is very necessary to strictly enforce the withdrawal period of anticoccidial drugs. .

Vaccinationedit

In order to deal with the drug resistance of coccidia, a new drug must be introduced every 1-2 years in the world. With the continuous improvement of people's environmental and health requirements, the cost of developing new drugs is getting higher and higher, so many pharmaceutical companies have given up on the development of new drugs. Another fact that must be recognized is that almost no medicine is perfect. Many medicines not only have toxic side effects, but their residues in meat and eggs also endanger human health. For this reason, a certain withdrawal period is stipulated. This makes poultry farmers and researchers face a serious problem, that is, how to avoid the outbreak of coccidiosis during drug withdrawal. Therefore, it is necessary to develop a vaccine for coccidiosis [9-17].

vaccine

2.1.1　 highly virulent strains of insects

This is the earliest coccidiosis vaccine used by people. The strains contained in it are directly isolated from the field without any weakening treatment. Such as Coccivac in the United States, Immucox in Canada, and live coccidia vaccines developed by Han Qian in my country. These vaccines are mainly used to vaccinate chickens at the age of 4 to 14 days by drinking water or mixing materials. After the chickens are reproduced, the offspring oocysts are spread on the bedding, allowing the chickens to gain immunity through repeated infections. Because this kind of coccidia vaccine uses a highly virulent strain, the large number of oocysts produced by reproducing chickens may cause disease in chickens that have not yet had time to develop a strong immunity. Therefore, the dosage should be carefully controlled during application to avoid harm to chickens.

2.1.2 　 Attenuated Insect Strains

This mainly includes coccidia strains weakened by methods such as physical and chemical treatment, chicken embryo passage, early maturity breeding, and late maturity breeding. For example, Paracox from the United Kingdom, Livacox from the Czech Republic, my country's Yang Zhenzhong developed the weakened E. tenella chicken embryo vaccine, the early-maturing strain vaccine developed by Duan Jiashu, and the EIMERICOX PLUS vaccine containing early-maturing and late-maturing strains launched by Suoxun , Fan Shengchao, etc. developed coccidia mixed seedlings made from double weakened coccidia strains and so on. These coccidia seedlings are mainly suitable for 5-10 day old chicks