Browsing by Person "Cheng, Yu-Chieh"

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The chicken gut microbiome in conventional and alternative production systems
(2025) Cheng, Yu-Chieh; Krieger, Margret; Korves, Anna-Maria; Camarinha‑Silva, Amélia
The poultry gut microbiome plays a key role in nutrient digestion, immune function, and overall health. Differences among various farming systems, including conventional, antibiotic-free, free-range, and organic systems, influence microbial composition and function through variations in diet, genetic selection, environmental exposure, and antibiotic use. Conventional systems typically rely on formulated diets and controlled housing conditions, often with routine antimicrobial use. In contrast, organic systems emphasize natural feed ingredients, including roughage, outdoor access, and strict limitations on the use of antibiotics. These divergent practices shape the gut microbiota differently, with organic systems generally associated with greater exposure to environmental microbes and, consequently, greater microbial diversity. However, the implications of this increased diversity for poultry health and performance are complex, as organic systems may also carry a higher risk of pathogen exposure. This review summarizes current findings on the chicken gut microbiome across conventional and alternative production systems (antibiotic-free, free-range, and organic), focusing on microbial diversity, functional potential, and disease resilience. The need for standardized methodologies and consistent nomenclature in microbiome research is also discussed to improve comparability across studies. Understanding how production systems influence the gut microbiota is essential for improving poultry health and productivity while addressing challenges related to antimicrobial resistance and sustainable farming practices.
Microbiota and nutrient portraits of European roe deer (Capreolus capreolus) rumen contents in characteristic Southern German habitats
(2023) Dahl, Sarah-Alica; Seifert, Jana; Camarinha-Silva, Amélia; Cheng, Yu-Chieh; Hernández-Arriaga, Angélica; Hudler, Martina; Windisch, Wilhelm; König, Andreas
Roe deer ( Capreolus capreolus ) are found in various habitats, from pure forest cultures to agricultural areas and mountains. In adapting to the geographically and seasonally differentiating food supply, they depend, above all, on an adapted microbiome. However, knowledge about the microbiome of wild ruminants still needs to be improved. There are only a few publications for individual species with a low number of samples. This study aims to identify a core microbiota for Bavarian roe deer and present nutrient and microbiota portraits of the individual habitat types. This study investigated the roe deer’s rumen (reticulorumen) content from seven different characteristic Bavarian habitat types. The focus was on the composition of nutrients, fermentation products, and the rumen bacterial community. A total of 311 roe deer samples were analysed, with the most even possible distribution per habitat, season, age class, and gender. Significant differences in nutrient concentrations and microbial composition were identified for the factors habitat, season, and age class. The highest crude protein content (plant protein and microbial) in the rumen was determined in the purely agricultural habitat (AG), the highest value of non-fibre carbohydrates in the alpine mountain forest, and the highest fibre content (neutral detergent fibre, NDF) in the pine forest habitat. Maximum values for fibre content go up to 70% NDF. The proportion of metabolites (ammonia, lactate, total volatile fatty acids) was highest in the Agriculture-Beech-Forest habitat (ABF). Correlations can be identified between adaptations in the microbiota and specific nutrient concentrations, as well as in strong fluctuations in ingested forage. In addition, a core bacterial community comprising five genera could be identified across all habitats, up to 44% of total relative abundance. As with all wild ruminants, many microbial genera remain largely unclassified at various taxonomic levels. This study provides a more in-depth insight into the diversity and complexity of the roe deer rumen microbiota. It highlights the key microorganisms responsible for converting naturally available nutrients of different botanical origins.