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Effect of Lactobacillus bacteria on feather-pecking behaviour and related physiological pathways in chickens

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Title: Effect of Lactobacillus bacteria on feather-pecking behaviour and related physiological pathways in chickens
Author: Mindus, Claire
Department: Department of Animal Biosciences
Program: Animal and Poultry Science
Advisor: Harlander, Alexandra
Abstract: The gut microbiota is a key regulator of the neuroimmune and neuroendocrine communication pathways of the brain-gut-microbiota axis. Disruption of the microbiome can lead to deterioration in gastrointestinal, neuroendocrine, immune functioning and may even contribute to the etiology and course of some psychiatric disorders. Some enteric bacteria, such as Lactobacillus species, have demonstrable beneficial effects on health and disease. Consequently, these organisms are used as probiotic supplements. Severe feather pecking (SFP) is a behaviour performed by laying hens which can lead to significant health and welfare issues. It remains one of the most challenging welfare and economic issues in the egg industry. Previous hypotheses of the causes of SFP considered external factors such as poor housing conditions as SFP triggers; however, ethology alone cannot fully explain this behaviour. Instead, birds displaying SFP also display distinct physiological characteristics relevant to an altered gut-brain microbiota axis. This includes differences in microbiota composition, namely a Lactobacillus-depleted gut microbiota and microbial metabolites, a more responsive immune system and altered aromatic amino acids metabolism. The objectives of this thesis were to assess the impact of a single-strain probiotic (Lactobacillus rhamnosus JB-1) supplementation on SFP behaviour, microbiota composition, T cell subpopulations and metabolism of aromatic amino acid in birds. To achieve this, diverse supplementation techniques were evaluated at various stages of life and in different genetic lines of birds under stressful or control situations. Disrupting social structures, restraining birds and/or removing basic housing structures were utilized to create an industry-like stressful environment. The results of this thesis suggest that therapeutic supplementation with Lactobacillus rhamnosus JB-1 is a promising tool, which reduces FP and feather damage, stress-induced cecal microbiota dysbiosis and, leads to a strong immunological effect characterized by T cell production in laying hens. Further research should investigate the impact of Lactobacillus supplementation in commercial farm settings.
Date: 2021-09
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Related Publications: Mindus, C., van Staaveren, N., Bharwani, A. et al. Ingestion of Lactobacillus rhamnosus modulates chronic stress-induced feather pecking in chickens. Sci Rep 11, 17119 (2021).
Embargoed Until: 2022-09-06

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