Impact of feed ingredients and dietary protein level on microbial activity in the digestive tract of broilers

D. Hoehler, A. Lemme, A.J.M. Jansman, C. Wagenaars

Research output: Chapter in Book/Report/Conference proceedingAbstract


Chicken diets have been supplemented with growth-promoting antibiotics for years. There are, however, increasing concerns regarding the use of those substances. Microbial activity and composition of microflora in the gastro-intestinal tract, intestinal health and mucosal function in broilers might be influenced by the choice of ingredients as well as by nutrient levels. Two experiments with male d old Ross 308 broilers following a 2 x 2 x 2 design were conducted using the experimental factors dietary protein level (19% or 25% in the starter diets and 18% or 24% in the grower diets), fish meal inclusion, and carbohydrate source (corn, wheat). Exp 1 was conducted to investigate the effects on performance and microbial activity in the digestive tract; Exp 2 was performed to examine the dietary effects under conditions of a combined challenge with E. acervulina and C. perfringens. In Exp 1, 1024 chicks were assigned to 64 floor pens resulting in 8 replicates per treatment with 16 birds per pen. At d 28 four birds per pen were selected to obtain digesta from the terminal ileum and the caeca. The remaining birds were fed until d 35. In Exp 2, 1408 chicks were distributed to 64 floor pens. Each treatment comprised 8 replicates with 22 birds per pen until d 35. Birds receiving the wheat based diets showed a higher feed intake than those fed corn based diets. Inclusion of fishmeal resulted in an improved performance at a high dietary protein level but not at low dietary protein. Both high dietary protein and fish meal addition resulted in an increased digesta ammonia content indicating a higher microbial breakdown of protein. Choice of cereals had no consistent effect on ammonia concentrations. Data suggest that microbial activity in the digestive tract can be manipulated by dietary means. Treatments did not affect the response towards a combined challenge with E. acervulina and C. perfringens. Other factors, such as hygiene or stress might have a much larger impact on the development of these diseases.
Original languageEnglish
Title of host publicationPoultry Science Association Annual Meeting, Edmonton, Canada, 16 - 19 July, 2006
Publication statusPublished - 2006
EventPoultry Science Association Annual Meeting -
Duration: 16 Jul 200619 Jul 2006


ConferencePoultry Science Association Annual Meeting


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