INFLUENCE OF CONTAMINATION OF ENVIRONMENT AND BREEDING CONDITIONS ON DEVELOPMENT OF COCCIDIOSIS IN CHICKENS Muriel Naciri, P. Yvoré, L. Conan To cite this version: Muriel Naciri, P. Yvoré, L. Conan. INFLUENCE OF CONTAMINATION OF ENVIRONMENT AND BREEDING CONDITIONS ON DEVELOPMENT OF COCCIDIOSIS IN CHICKENS. Annales de Recherches Vétérinaires, INRA Editions, 1982, 13 (1), pp.117-121. <hal-00901364> HAL Id: hal-00901364 https://hal.archives-ouvertes.fr/hal-00901364 Submitted on 1 Jan 1982 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
L apparition INFLUENCE OF CONTAMINATION OF ENVIRONMENT AND BREEDING CONDITIONS ON DEVELOPMENT OF COCCIDIOSIS IN CHICKENS Muriel NACIRI P. YVORÉ L. 2CONAN 1 //WM, CR de Tours Nouzilly, Station de Pathologie Aviaire et de Parasitologie, 37380 Monnaie, France 2 INRA, Domaine Expérimental du Magneraud, Saint-Pierre-d Amilly, BP 2, 17700 Surgères, France Résumé INFLUENCE DE LA CONTAMINATION DU MILIEU ET DES CONDITIONS D ÉLEVAGE SUR LE - DÉVELOPPEMENT D UNE COCCIDIOSE CHEZ LE POULET. d une coccidiose clinique n est pas inévitable même en milieu fortement contaminé et en l absence d anticoccidiens. Cependant, les performances sont toujours significativement abaissées et les indices de conversion augmentés. Les conditions d élevage jouent un rôle dans le maintien de l équilibre entre l hôte et son parasite. Nos résultats montrent que les fortes densités augmentent le risque d une coccidiose clinique. Breeding conditions play an important role in etiopathogeny of avian coccidiosis. They intervene, favouring to a greater or lesser extent contamination of animals and modifying the susceptibility of those subjected to breeding stress. It seems that breeding of several flocks of chickens at high density on the same litter must favour development of this parasitism. Anticoccidial drugs used in chemoprevention may act at three levels : protection of the animal in a contaminated environment, reduction in oocyst excretion, and effect on development of the latter up to the infective stage. These three types of effect are not necessarily linked and certain anticoccidial drugs guarantee excellent protection of animals without diminishing parasitic development to a very great extent (Naciri et a/., 1981). In this study, carried out on floor pen litters, we have compared behaviour and performances of chickens bred at low density (14 per m2), or high density (25 per m2) without chemoprevention, on litters which were contaminated in various levels at the time of their introduction. Materials and Methods 1. Animals The study was carried out in the form of two experiments conducted in floor pens at 14 per m2 and 25 per m2. Experimental design consisted of 24 floor pens with wood shaving litters. Sexes were segregated. In each experiment two successive flocks of chickens of the same stock were bred successively on litters.
2. Experimental infeed contamination Animals of the first flock were divided into several groups infected artificially from 13 days of age and over a period of four days administering feed containing coccidial oocysts (Yvoré et al., 1980). An average of 15 000 Eimeria tenella oocysts and 100000 E. acervulina oocysts per animal per day were administered. 3. Anticoccidial treatment In addition, with the exception of an infected non-treated group, chickens received throughout the whole of the breeding period feed supplemented with an anticoccidial drug which varied according to the group. the first flock, new chickens of the same stock as the preceeding ones were introduced into the litters, which had not undergone any treatment. These animals received no anticoccidial drug. Progress in their behaviour, mortality, performances (individual weighing, measurements of feed consumption per pen and calculation of feed conversion index) was observed throughout the breeding period. Animals were slaughtered at the same age as those of the first flock. 6. Analysis Analysis of variance (Fisher test) and comparison of means (Duncan test) were used for all criteria studied. 4. Measurements Performances of animals and degree of litter contamination were measured at different times throughout the breeding period, and in particular at the end of it. The evaluation of litter contamination is expressed by oocysts sporulated per gramme of faeces according to the principle proposed by us (Naciri et al, 19811. 5. Contamination by litter Fifteen days after elimination of the animals in Results 1. Performances Tables 1 and 2 show average weights and conversion indices of animals in the different groups at the end of the breeding period. Also shown are results of groups in the first flock of chickens (infected non-treated and infected treated control groups) and evaluation of initial litter contamination before the second flock of animals was introduced. We note that if indices were better for animals
bred at a density of 14 per m2 (table 11, average weights at 45 days of age are practically the same as at 25 per m2 (table 2). Furthermore, whatever the initial extent of litter contamination, performances are the same in all groups of the second flock of chickens and these performances are the same as those of the infected non-treated group in the first flock. There was therefore a significant reduction in the final weight (about 5 to 7 %) and a significant increase in the index. These changes may be attributed to parasitism. 2. Mortality Mortality in the two flocks of chickens was much higher in breeding at a density of 25 per m2 (table 3) and a large number of deaths by cecal coccidiosis were recorded during the period day 10 to day 28 in particular. There are no apparent differences according to groups.
Discussion Contrary to what one may think, initial level of litter contamination by oocysts, which appear to be infective, did not influence the extent of parasitic effect. Outbreak of clinical coccidiosis in animals not protected by an anticoccidial drug is not certain to occur even if the environment is contaminated to quite a large extent. Inapparent parasitism does however weaken performances. Even if clinical coccidiosis is not certain to occur, it is favoured by high densities. We have observed elsewhere the same phenomenon in «in-feed» experimental infections (Yvoré et al., 1980) or in those involving «seeder birds»: under the same general conditions and with the same inoculum, mortality by coccidiosis, non-existent or infrequent at low densities, was observed or increased at high densities. The role played by breeding conditions in the outbreak of coccidiosis has already been pointed out. Some studies have for example shown the importance of temperature and hygrometry (Anderson et al., 1976 ; Reid et al., 1976 ; Stoyanov et al., 1978). Density also seems to play a part. If level of initial contamination had no effect on development of coccidiosis in our groups which had not undergone chemoprevention, this is not the case at all when an anticoccidial drug is administered. We have shown (Yvoré et al., 1980) that an anticoccidial drug gave better protection to animals with a slight infection, independent of all problems of chemoresistance. Conclusion Two important facts are emphasised by our results : Firstly, the complex character of the etiopathogeny of coccidiosis. For the «disease» to occur, in a form which includes a simple lowering of the level of performances, the parasite obviously needs to be present. This is almost always the case in bird-breeding. This presence, however, is not sufficient. Environmental conditions are needed which favour the expression of the pathogenicity of the parasite. This emphasises the importance of breeding conditions and of sanitary measures as a whole. Secondly, if the anticoccidial drug is merely one of the elements which contributes to a suitable balance between host and parasite, it is generally the main element which needs to be used in good conditions and by following techniques which permit its efficacy to be preserved. The example of the influence density has shown that control of parasitism by chemoprevention in very intensive breeding will be more difficult and failure more likely. In this case, it will certainly be of interest to resort to the rapid alternance technique (Shuttle program). Taking into consideration conditions which favour parasitic development, this technique can prevent or at least delay the appearance of strains which are less sensitive or resistant to a certain anticoccidial drug. Accepied for publication, March 9th 1982. Summary Outbreak of clinical coccidiosis does not always occur even in a highly contaminated environment and in the absence of an anticoccidial drug. Performances, however, are always significantly poorer and feed conversion indices higher. Breeding conditions play a role in maintaining the balance between host and parasite. Our results show that high densities increase the risk of clinical coccidiosis. References ANDERSON W.I., REID W.M., JOHNSON J.K., 1976. Effects of high environmental temperatures on cecal coccidiosis. Poult Sci., 55, 1429-1435. NACIRI M., YVORE P., CONAN L., 1981. Evaluation of the effect of anticoccidial drugs on size of parasite population and its development in litters. Ann. Rech. V6t., 13, 79-83.
REID W.M., HINES T.K., JOHNSON J., STINO K.R., 1976. Coccidiosis : effects of high environmental temperatures on anticoccidial protection. Poult. Sci., 55, 1436-1441. 1. STOYANOV P., SHERKOV S.H., GFORGIEV G., IVANOVICH R., 1978. (The effect of temperature and humidity on the resistance of chicks to experimental coccidiosis and on the efficacy of coccidiostats) (in Bulgarian). Veterinarnomed. Nauki, 15 (8), 105-114. YVORE P., RAYNAUD J.P., CONAN L., NACIRI M., VIRAT M., 1980. Method of evaluating the efficiency of anticoccidial drugs in floor-pen trials with multiple in-feed infection versus «Seeding» model. Ann. Rech. V6t., 11, 99-108.