Coccidiosis and Anticoccidials - Their Relationship to Nutriture of the Chicken

Willis, Gawain Merlin

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Description

Title

Coccidiosis and Anticoccidials - Their Relationship to Nutriture of the Chicken

Author(s)

Willis, Gawain Merlin

Issue Date

1981

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Agriculture, Animal Culture and Nutrition

Language

eng

Abstract

• The research detailed herein concerned (1) establishing a model system for estimating the chick's nutrient requirements during coccidiosis, (2) estimating the chick's sulfur amino acid (SAA) requirements during Eimeria acervulina infection, (3) evaluating the interaction between E. acervulina and certain amino acids, and (4) evaluating the interaction between dietary protein source and anticoccidial drugs.
• E. maxima inoculations of 5 x 10('4) oocysts and E. acervulina inoculations of 2 x 10('5) to 4 x 10('5) oocysts were shown to depress the growth of chicks fed crystalline amino acid diets (CAA) by 15 to 20%. The intestinal lesions produced were typical of light to moderate coccidiosis. The performance of chicks fed anticoccidial drugs in CAA diets was increased in the presence, but not in the absence, of E. acervulina. This coccidiosis x coccidiostat interaction was taken as evidence of an active coccidiosis infection.
• Severe E. acervulina infections were produced by inoculations of 1 x 10('6) or 2 x 10('6) oocysts. Under these conditions gain were depressed by 30 to 40% and the intestinal lesions produced were indicative of severe coccidiosis. Also, E. acervulina infections were more severe in birds fed CAA diets than in those fed corn-soybean meal diets. Based upon growth rate, intestinal lesions, and responses to anticoccidial drugs, it was clearly demonstrated that coccidiosis of varying severity can be produced in birds fed CAA diets. In addition, it was observed that the CAA diet, with 24.58% amino acids, contained adequate levels of all indispensible nutrients, even during coccidiosis. This assures that the diet can be used effectively for nutrient requirement studies during coccidiosis.
• Initial studies designed to assess the chick's SAA requirement during E. acervulina infection were somewhat inconclusive. In one experiment, infected birds responded to levels of SAA above those required by healthy birds; but in two subsequent assays, no difference in SAA requirements due to infection could be detected. Therefore, additional assays were conducted with birds suffering from severe coccidiosis. In none of these assays did infection show any indication of altering SAA utilization. When data from all studies were viewed together, it was clear the E. acervulina infection did not increase the chick's SAA requirement. Nonetheless, a striking and unexpected infection x SAA interaction was discovered.
• When chicks were fed diets severely deficient in SAA, E. acervulina infection produced a marked growth response, while birds consuming SAA adequate diets exhibited the expected severe growth depression when given the same dose of oocysts. Although the interaction was originally demonstrated in birds fed CAA diets, it was subsequently demonstrated with intact-protein diets as well. The interaction was also shown not to be unique to the SAA. Thus, lysine and E. acervulina interacted in the same manner. It was also established that the growth response to infection resulted directly from E. acervulina per se and not from any other component of the infective inoculum.
• Finally, assays were conducted to evaluate the alleged interaction between the anticoccidial drugs, monensin and lasalocid, and dietary protein source. Protein-source x coccidiostat interactions were not detected in any experiment. Adding the recommended level of monensin or lasalocid to the diet depressed performance in only one experiment. Anticoccidial efficacy of monensin and lasalocid was not altered by diet type. Hence, neither level nor source of animal protein (as a replacement for soybean protein) affected the response to ionophorous coccidiostats in either coccidiosis infected or control birds.

Graduation Semester

1981

Type of Resource

text

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