Breeders to broilers: optimising chicken health and performance to reduce susceptibility to zoonotic bacteria, viruses, and parasite colonisation.

Healthily maintained livestock are essential for economic and societal prosperity. As the world population grows (around 9 billion by 2050), poultry will become the main source of protein and it is paramount we not only investigate methods to optimise bird health and performance, but simultaneously reduce susceptibility to zoonotic bacteria, virus and parasite colonisation (1). This reduced susceptibility can positively impact animal and human health and lessen antimicrobial usage.

Genetic selection and feed formulation have led to high standards of broiler production, however there still exists variability between farms and successive flocks (2). In broilers (chickens specifically raised for their meat), feed conversion and their health status is heavily dependent on the complex gut microbiome which plays a role in nutrient assimilation, vitamin and amino acid production and prevention of pathogen colonisation (3). Very little is known about parent breeder flocks and how the respective microbiome can impact chicken health, performance and the susceptibility to zoonotic bacteria, virus and parasite colonisation of downstream broilers.

Our previous studies have begun to demonstrate the differences that exist in the levels of zoonotic bacteria colonisation from across and within commercial broiler lines (4, 5). Selective breeding of poultry to increase resistance to zoonotic bacteria (e.g., Campylobacter, Salmonella and Escherichia), viruses and parasites is an attractive control strategy (6). Genome-wide association studies (GWAS) in commercial broiler populations have indicated that resistance to caecal colonisation of specific zoonotic pathogens is under moderate genetic control (7). Moreover, heritable differences in resistance have been associated with quantitative trait loci, and the transcription of genes related to immunity (7). The overarching project aim is to characterise how breeders and commercial broiler microbiomes and host genetics translate to optimised bird health and performance in conjunction with a reduced susceptibility to zoonotic bacteria, virus and parasite colonisation. These findings can have a direct positive impact on both animal and human health.

The PhD Objectives: -
(i) Characterise the microbiomes of high and low performing breeder chickens in relation to animal health, and susceptibility to zoonotic bacteria, virus and parasite colonisation.
(ii) Investigate the impact of breeder hatching day on downstream broiler microbiomes, health, performance and susceptibility to zoonotic bacteria, virus and parasite colonisation.
(iii) Investigate breeder and broiler host genetics to map genetic regions associated with bird health, performance and susceptibility to zoonotic bacteria, virus and parasite gut colonisation.