Ecological chicken meat production: Prevention of coccidiosis using not pharmacological methods.
ProducciĂłn Animal, E.U.I. Agrarias del Soria, Campus de Soria, 42004, Soria
*ParasitologĂa y Enfermedades Parasitarias, Facultad de Veterinaria de Zaragoza
Miguel Servet, 177.50013. Zaragoza
One of the main problems in ecological chicken production is the prohibition of pharmacological products administration, what makes difficult to control some frequent parasitosis like coccidiosis.
Â As an alternative to treatment with sodic monensin against this disease, in this study, they are presented the results obtained using one herbal product (Alquernat ZycoxÂ®), one vaccine based in attenuated oocists by precocity and sodic monensin, as alternatives in prevention and treatment of coccidiosis in a chicken population of Castellana Negra breed.
Weight control was done each 2 weeks, from 4 to 12 weeks, and at 9 weeks animals were subjected to assay infection with pathogenic oocists. At 10, 11 and 12 weeks, number of oocists present in faeces was analyzed and also the level of intestinal injuries in animals (totals and by species).
Daily weight average gain and growth of animals treated with Alquernat Zycox Â® and the vaccine it was similar and more regular than animals treated with sodic monensin. From the analysis of number of oocists in faeces, it was observed that vaccinated animals eliminated a lower quantity than animals treated with monensin. Also, vaccinated animals had a lower number of oocists in faeces at 11 and 12 weeks than the ones treated with Alquernat Zycox Â®. The level of injuries at weeks 11 and 12 was significantly lower in vaccinated animals and with Alquernat Zycox Â® than the ones with monensin. It was studies at different ages the level of injuries by different species of Eimeria; at 10 weeks it was observed that vaccinated animals presented less damage by E.tenella and E.maxima and there was no difference in E.acervulina. At 11 weeks injuries produced by E.tenella and E.maxima were less in vaccinated animals and treated with Alquernat Zycox Â®, having less injuries vaccinated animals in case of E.acervulina. The same thing happened at week 12 with E.tenella and E.maxima, there was no difference between the three treatments against E.acervulina.
Avian coccidiosis is a parasitosis with high economic incidence in poultry industry. There is no existence of proved data about economical losses produced due to clinical shoots of the disease, but it is appreciated one annual loss caused by avian coccidiosis of 1500 million euros (Escoda, 2003). Although they may be statistics difficult to check, losses are very high.
The features of poultry farms, with high density of birds, high temperatures and wet floors, they all favour appearance of clinical coccidiosis shoots. Economical losses caused by coccidiosis extend through all life long of the animal with growth delays, increase of feed conversion rate and more sensitivity of birds to infection by other agents, like Salmonella and Clostridium. It has to be added the effect onto dressed carcass pigmentation, it decreases because of lower level of plasmatic carotenoids.
Nowadays, there are lots of chances in coccidiostats market, being the ionophores the most demanded in poultry industry (Frigg and col. 1983; Anadon and MartĂnez-LarraĂ±aga, 1990). However, some studies show how careful anticoccidial therapy must be, to avoid risk of resistances to medicines (Ruff, 1993).
In addition to that we have to mention the recent legislation standards that oblige to do without, and more each day, the use of several pharmacs in animal feeding.
According to this, each time is more important the use of vaccines, having the chance to restore Eimeria species which had been removed by resistant ones, and so, restoring sensitivity to medicines (Chapman, 2000).
In the present work of research they are shown results obtained from chickens submitted to prevention treatments with a ionophore coccidiostat, another coccidiostat composed by plant extracts, and with a vaccine, even in growing parameters or in injuries level and number of oocists in faeces. This way, it is possible to compare the different mechanisms of action: in case of ionophore coccidiostat, monensin acts upon traffic of Na+ and K+ through cellular membrane, changing it and creating osmotic imbalances that finally are to kill the parasite; the coccidiostat based on plant extracts, optimizes mucose status and naturally improves local immunity against different species of coccidia, and the vaccine with attenuated premature oocists, once it is administrated in first days of life in chickens, determines a protection status to all productive cycle long.
Material and Methods
Animals used were chickens of one day of life, from autochthonous breed Castellana Negra, all them males, and divided in three batches of 35 birds each one.
Animals from batch 1 had eaten ecological feed supplied with sodic monensin (50 ppm) to th eones in batch 2 it was added to feed a coccidiostat based on plants (1000 ppm), Alquernat Zycox Â® (BIOVET, S.A.), composed by Holarrhena antidysenterica (30%), Berberis aristata (30%), Allium sativum (15%) and Embella ribes (15%) which constituents are phenols, essential oils, phytoproteins with high quality sulfured aminoacids and glycosides, and the ones from batch 3 they were vaccinated with premature oocists of E. acervulina, E. maxima and E. tenella, manufactured and administrated by the Group of applied research in coccidiosis subsidied by AragĂłn Government. Vaccine was given the first day of life orally and animals hade aten the same ecological feed ( with no coccidiostat addition), based in cereal grain, subproducts of oleaginous seeds, oils and fats, and minerals, which composition is shown in table 1. All chickens were fed ad libitum and the three batches were housed in close yards onto bed.
Tabla 1: Bromathological composition of feed
At 9 weeks of life, they were submitted to experimental infection with pathogen oocists collected from field samples. The infectious inoculum was composed of 10.000 E. tenella oocists, 100.000 E. acervulina oocists and 15.000 more of E. maxima.
At weeks 10, 11 and 12 of life 4 chickens were slaughtered from each batch, and levels of intestine injuries were evaluated (Johnson & Reid, 1970). At the same time, it was determined the number of oocists/gr of faeces, by the use of Mc Master cameras.
The weight of the batch was determined each two weeks, from week 4 to week 12, at the time the assay ended.
With the data obtained, it was made a variance analysis with statistic pack SPSS 10.0 version.
Results and Discussion
There was no death registered, in any batch, all assay long.
According to weight (table 2), no significant differences were found, although vaccinated animals and those treated with plant extracts had a better growth. Moreover, weight gain in animals of those two batches kept the same parameters all assay long, being more regular animals growth in those which had received Alquernat Zycox or vaccine, it is quite similar, taking into account the alteration produced in week 10, as a consequence of experimental infection.
Tabla 2: Weight control and daily average gain (D.A.G.) of the whole batch (grams).
There is no significant differences in weight and daily average gain,(p<0,001). However, higher regularity is appreciated in animals from batches 2 and 3, being batch 3 the one with less decrease in growth alter experimental infection at week 9. Animals from batch 1, which received monensin treatment, they have irregular growing in relation to the other two groups, being better than these in week 10 but with a sharp decrease in week 11.
In table 3, results are shown from coprology analysis, done in 10, 11 and 12 weeks of life. Statistic analysis proved that vaccinated animals eliminated quantity of oocists significantly lower (p<0,001) than animals fed with monensin.
Tabla 3: Number of oocists/gr faeces.
Â Â P<0,001
All assay long, higher number of oocists were found in faces of animals fed with monensin. Although in week 10 thereâ€™s no significant difference (p<0,001) between number of oocists in faeces from animals fed with Alquernat Zycox and the vaccinated, in weeks 10 and 11, yes, in favour to those animals which were vaccinated.
Â In table 4, results of injuries are shown, valued from 0 to 4, at 10, 11 and 12 weeks of life, significant differences are noticed (p<0,05) between two batches and lower in vaccinated animals.
Tabla 4: Injuries level with no distinction between Eimeria species.
In weeks 11 and 12, injuries level is significantly lower in animals treated with plant extracts and the vaccinated, in relation to those treated with monensin. In week 10 there are only significant differences (p<0,05) between these last ones and the vaccinated, being these the ones with lower level of injuries.
Taking a look at all recently exposed, the treatment with worse results was the one with monensin, with no differences found in results obtained with the other two treatments.
In table 5, it is shown injury level for each batch, taking into account Eimeria specie and week of life.
Tabla 5: Injury level for Eimeria species and weeks.
In week 10, it is noticed how injuries caused by E. tenella and E. maxima are significantly lower (p<0,05) in vaccinated animals than in the other two batches. However, there are no differences in injuries level by E. acervulina in different treatments.
In week 11, level of injuries by E. tenella and E. maxima is significantly lower (p<0,05) in animals fed with Alquernat Zycox and the vaccinated ones. In case of E. acervulina, injuries were significantly lower (p<0,05) in the vaccinated ones.
In week 12, it is noticed that level of injuries caused by E. tenella and E. maxima is significantly higher (p<0,05) in animals treated with monensin, than in the other two treatments, with no difference found for E. acervulina.
In accordance with the results previously exposed, we can conclude that the worse results were given by sodic monensin treatment. Except from little changes in some concrete weeks and analyzing results globally, we can make sure that animals treated with Alquernat Zycox or vaccine they gave similar results. However, monensin administration determined an increase statistically significant in intestinal injuries and irregular growth of chickens.
Therefore, we can suggest that substitution ofÂ pharmacological coccidiostats by natural products is not only possible, but recommendable. Substitution of pharmacological products will avoid derived problems of residues gathered in meat, the same as interaction of these products with others of regularly used in poultry industry (antibiotics, antioxidants, etc.) (Dowling, 1992). Moreover those reasons, related to meat quality, efficacy reasons may be suggested because most trials, including our results, have proved that plants extracts and vaccines bring similar productive parameters to the ones reached by pharmacological coccidiostats (Shirley 1989, Youn & Noh, 2001).
Ecological chicken production is controlled by Regulations (CE) no. 1804/1999 and no. 2092/91 which forbid administration of pharmacological products. Therefore, in this kind of production the control of coccidiosis can only be made with vaccines and plant extracts registered as â€śDietetic Suppliesâ€ť. Our results prove that vaccination and administration of a coccidiostat composed by plant extracts, are two ways to fight with efficacy against avian coccidiosis. In accordance with our results to confirm other ones obtained by other authors, we may suggest that these alternative treatments had higher efficacy than administration of ionophore coccidiostats, like monensin, probably due to massive use of these pharmacs has originated resistant strains (Chapman, 1993).
Nowadays, pharmacologicalÂ coccidiostats are the most used method to control avian coccidiosis, added to feed in quality of additives. However, actually, the European Commission has decided to restrict the use of pharmacological coccidiostats, as it may be checked with appearance ofÂ RegulationÂ (CE) no 2205/2001, that withdrew authorisation of Amprolium, Amprolium-etopabate, Dimetridazol, Metilclorpindol, Nicarbazin and Metilclorpindol/metilbenzocuate. The possibility of pharmacological coccidiostats to lose its quality of additives has enhanced the development of other control methods. Among them, vaccines and plant extracts are the most effectives. Vaccines, composed by Eimeria premature attenuated strains, have been used massively during years giving productive results similar to the ones offered by pharmacological coccidiostats (Shirley et al., 1995). Plant extracts do not have been proved massively in poultry industry and some parameters like accumulation in muscles, organoleptic changes in meat and impacts on consumers are still not exactly known. If they are able to perform these controls, they could be products of easy administration and with lower price than vaccines.
This study has been subsided, in part, by D.G.A. (Consolidated Group of Applied Research in Coccidiosis).
Â Bibliographic References
Anadon, A. y MartĂnez â€“ LarraĂ±aga, M.R. 1990. Interacciones TĂłxicas con ionĂłforos. Rev. Univ. Complutense. Facultad de Medicina. Dpto. de FarmacologĂa. Madrid.
Chapman, H.D. 2000. Practical use of vaccines for the control of coccidiosis in the chicken. Worldâ€™s Poultry Science Journal, Vol. 56, 7-20.
Escoda, C. 2003. Coccidiosis Aviar: mĂ©todos actuales de control. Selecciones AvĂcola. Vol. XLV, 559-567
Dr. Roberto JimĂ©nez Torres, Dr. RenĂˇn Medina DomenzĂˇin, Dr. Gabriel Ruiz CastaĂ±eda, Dra. Martha Elba GutiĂ©rrez Vargas
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