The control of avian coccidiosis since the 1940s has been associated with the use of ionophores and chemical drugs. Recently, a significant interest in natural sources has developed due to the pressure to poultry industry to produce drug-free birds. Consequently, the search of products derived from plants and other natural sources has increased in the last years. Today, many commercial products containing essential oils, extracts, and other compounds are available. The use of these compounds of natural origin is related to an increased immune response, a body weight gain, destruction of oocyst, among other benefits. The main inconvenience of these products is the act on some species of Eimeria, but not all. This genetic variability found in the parasite makes the use of products difficult to control and treat coccidiosis. In this chapter, several proposals of treatment are presented based on the use of natural products, considering the new strategies of treatment with minimal consequences to birds.
- natural treatments
- herbal extracts
Chickens’ production is positioned as an important source of meat around the world. About 60 billion chickens are produced worldwide every year. However,
The life cycle of the
The main problem of coccidiosis treatment is that the resistance to anticoccidial drugs can evolve rapidly leading to a continuing need to develop novel and effective therapies .
In this chapter, avian coccidiosis is briefly reviewed and a special focus on novel strategies of treatment is presented. The strategies include the use of herbal compounds to genomic analysis of
2. Avian coccidiosis
Poultry industry raises approximately 40 billion chickens annually and more than 100 tonnes of chicken meat. Today, there exist a growing demand of this meat not only because it is cheaper than other types of meat, but also due to the increasing number of inhabitants around the world . In spite of the high production of poultry industry which still exists, some factors are affecting the productivity such as handling, housing, and rearing of birds in addition to disease control (nutritional, metabolic, and parasitic diseases) .
2.1. Causative agents of coccidiosis
Avian coccidiosis is a parasitic disease caused by protozoa belonging to the phylum Apicomplexa, genus
More than 1200 species of
In domestic fowl (
|Species||Site of development||Pathogenicity||Disease type|
|Jejunum, ileum, caeca||+++++||Hemorrhagic|
|Caeca and rectum||++++||Hemorrhagic|
2.2. Life cycle
During the sporogony, which is considered a noninfective stage, the oocyst is excreted in chicken feces and undergoes sporulation in the presence of humidity, warmth, and oxygen and thus becoming a sporulated oocyst, now infective. Merogony or schizogony occurs in the intestine and comprises of several rounds of asexual multiple division (from two to four times), followed by gametogony that involves the formation of male and female gametes, fertilization and formation of a zygote (oocyst) that will be excreted in feces . Infection starts when the host ingest sporulated oocysts (Figure 1).
Due to the chemical and mechanical proventriculus and gizzard action, and the presence of CO2 in the lumen, the oocyst releases the sporozoites, which gets the intestinal lumen and attached to enterocytes using this anchoring and penetration proteins present in the apical complex (rhoptries and micronemes) entering the cell in order to continue the second phase: esquizogony or merogony, producing a schizont with thousands of merozoites inside to be released back into the lumen to infect new intestinal cells. Thus, after several stages of merogonies, some of the merozoites inside the intestinal cell forms macrogamonts with a macrogametocyte (inmobile cell considered the female gamete) and some forms microgamonts with several microgametocytes inside (mobile cells considered male gametes). These microgametocytes come out of the cells that originated to locate and fertilize to macrogametocyte producing a zygote to be excreted in the feces again (not sporulated oocyst) to begin another cycle  Figure 2.
Once the oocyst is formed, it is considered the most persistent structure of
The unsporulated oocyst is considered as the noninfective stage while the sporulated oocyst is the infective stage, in
Environmental factors such as humidity (40–80%), temperature (24–28°C), and oxygen supply (aeration) makes the sporulation occurs, at least in
3. Strategies of treatment
During the last years, research has focused on development of anticoccidial drugs, with interest focused on the sexual and asexual stages of the parasites (stages occurring within the host). However, exists a tendency to ban the use of drugs in animals for human consumption, so the development of new drugs to control avian coccidiosis demands another way to control the disease.
The control of avian coccidiosis is a challenge of veterinary parasitology. So far, any treatment, including, anticoccidial drugs, vaccines, or natural alternatives control avian coccidiosis by itself. It proposed the use of combination of different strategies to achieve an effective control (Figure 5).
This treatment comprises of ionophorous compounds (ionophores) and synthetic drugs (chemicals). Ionophores usually cause the death of parasite and are produced by the fermentation and chemicals inhibit several biochemical pathways of the parasite and are produced by chemical synthesis [17, 18]. In Table 2, the most important ionophores and chemicals are shown.
|Ionophores||Lasalocid, Monensin, Narasinm Salinomycin, and Semduramicin||Disruption of ion gradient across the parasite cell membrane|
|Chemicals||Quinolone drugs (Decoquinate and nequinatem buquinolate).|
|Inhibition of parasite mitochondrial respiration|
|Sulphonamides||Inhibition of the folic acid pathway|
|Amprolium||Competitive inhibition of thiamine uptake|
|Diclazuril, Halofuginone, and Robenidine||Mode of action unknown|
|Nicarbazin||Inhibition of the development of the first and second generations of the schizont stage of the parasites|
However, after prolonged uses of a drug treatment, several drug-resistant strains may emerge, which represents a severe problem . To combat resistance, shuttle, mix, and rotation systems of drugs are employed.
Passive or active immune responses induce immunity in animals. This immunity can reduce the pathogenic effects of coccidiosis such as less macroscopically visible lesions, decreasing of oocyst production, and increasing performance of birds .
The first commercial live coccidiosis vaccine was CocciVac® registered in the USA in 1952 . Currently, two types of vaccines are used with the aim of controlling coccidiosis in a chemical-free way: nonattenuated and attenuated vaccines.
The main risk of using live nonattenuated vaccines (Coccivac, Advent, Immucox, and Inovocox) is the live parasites that can develop a severe reaction in birds. Many times their use is accompanied by chemical treatments to control the inherent pathogenicity of the parasites .
On the contrary, the success of live attenuated vaccines (Paracox and HatchPak CocciIII) relies on the low risk of disease occurring because of the reduction in the proliferation of parasites and consequently a less damage in birds’ tissue .
Nonattenuated and attenuated vaccines may have different routes of administration (oral, eyes drops, in ovo) in birds and several
Subunit vaccines consist of purified antigenic determinants obtained from
These kinds of vaccines involve native or recombinant subunit second generation extract or DNA vaccines. The only commercial subunit vaccine was CoxAbic®, based on purified native protein isolated from gametocytes of
Proteomic analysis of
A collection of epitope mapping of T-cell mediated antigenic determinants was applied in an
So far, the use of recombinant vaccines is limited mainly due to the low protection of antigens with the potential to induce potent protective immune response against
3.3. Natural compounds, alternative treatments
The search of alternatives to anticoccidial drugs and vaccines against avian coccidiosis has led to discover in fungal extracts, plant extracts, and probiotics a source of new compounds with anticoccidial activity. Many of them with the oocyst as target being that if the dispersion of oocysts is controlled then the possibilities of infection reduce.
The role of fats, essential oils and herbal and medicinal plants has been explored to control avian coccidiosis.
Fatty acids from fish or flax seeds reduce the severity of
3.3.2. Essential oils
The use of essential oils as a therapy to control
Functional oils comprise those oils that have an action beyond nutritional value . Recently, a variety of essential have been used at different stages of life cycle of
In vitro assays are used to test potential oocysticidal activity of essential oils. The use of oils from Artemisia, thyme, tea tree, and clove showed a clear destruction of oocyst after 3 hours of treatment and a LC50 < 1 mg/ml of oocyst . Commercial oils carvacol, carvone, isopulegol, thymol, and eugenol were used to destroy a mixture of
A commercial essential oils product called Essential (Oligo Basics Agroind. Ltda, www.oligobasics.com.br) containing ricinoleic acid and alkylphenolic oil of the shell of the cashew nut (
3.3.3. Herbal derivatives
A total of 68 plants and phytocompounds with proven suppression of
The usage of these plants varies from organic extracts (ethanol, petroleum ether and acetone extracts), ground powder, essential oils, and decoction. The parameters measured to evaluate efficiency of the anticoccidial compounds are body weight gain, oocyst count, feed consumption, lesion scores, bloody diarrhea, and mortality [7, 32]. Recently, plant
|Inhibition of ||Artemisin (||Induce reactive oxygen species (ROS) that inhibit oocyst wall formation and sporulation|
|Tannins, Pine (||Inhibition of life cycle and decreased sporulation of the oocyst|
|Allicin and sulfur compounds, Garlic (||Antimicrobial activity and inhibition of sporulation of |
|Selenium, Phenolics and Green tea ||Inhibition of sporulation of coccidian oocysts.|
|Papain ||Inhibition of coccidiosis probably by proteolytic degradation of |
|Saponins ||Suppression of coccidiosis|
|Essential oils from thyme, tea tree and clove||Destruction of |
|Ethyl acetate extract (||Destruction of |
|Immune response modulators||Probiotics (||Enhanced humoral immunity, changes in body weight gain and fecal oocyst shedding rates.|
|Arabinoxylans (||Immunostimulatory and protective effects against coccidiosis in broiler chickens|
|Sugar cane (|
|Polysaccharides (||Enhancement of anticoccidial antibodies and antigen-specific cell proliferation in splenocytes via cellular and humoral immunity to |
|Phytonutrients mixtures: VAC (carvacrol, cinnamaldehyde, |
|Protection against |
|Lectins (||Enhancement of both cellular and humoral immune response|
The use of these compounds is not limited to laboratory conditions, many products that contain natural compounds are commercially available for prevention and treatment of coccidiosis. This highlights their potential use in poultry industry. In Table 4, commercial natural products are show.
|Essential||Ricinoleic acid and alkylphenolic oil of the shell of the cashew nut (||Oligo Basics Agroind. Ltda,|
|Avihicox||Clove and ||Centaur|
|Nutrimin||Apple cider vinegar||Chicken Lickin|
|Kochi free||Olive leaf, mustard seed, black seed, cloves, grapefruit seed extract||Amber Technology|
|Coccinon||Blend of plant extracts and natural compounds||Natural farm health|
|Oil of oregano||80% Carvacrol||Natural factors|
|Garlic granules||Garlic||Flyte so fancy|
|Poultry Provita||Probiotics and prebiotic inulin||Vets plus|
|Eimericox||Blend of essential oils||Phytosynthese/Trouw nutrition|
|Enteroguard||Garlic and cinnamon||Orffa|
4. Future vision of avian coccidiosis
The development of new treatments against avian coccidiosis is a challenge to many researchers. However, information of parasites still can be revealed using new strategies such as omics approaches. Recently, a transcriptional profile analysis of virulent and precocious strains of
The vaccine development against
The recent studies of
The development of drugs to control and treat avian coccidiosis since the 1940s until now has increased significantly leading to a wide variety of products. The use of these drugs interferes with cofactor synthesis, mitochondrial functions, and cell membrane function of
This view guided research efforts to search for new compounds with a natural origin. Thus, plants, fungi, and bacteria were considered sources of metabolites and molecules with potential anticoccidial activity. In this chapter, we present recent information related to compounds that can be used to prevent, control, and treat avian coccidiosis. Many of them were with good results when an immune response is involved.
This disease may not be controlled or treated with the use of only one compound, on the contrary, it requires the combination of immunostimulators that induce a good response in bird and herbal extracts, essential oils and other natural compounds that can destroy