Institut für Nutztierwissenschaften
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Publication The active core microbiota of two high-yielding laying hen breeds fed with different levels of calcium and phosphorus(2022) Roth, Christoph; Sims, Tanja; Rodehutscord, Markus; Seifert, Jana; Camarinha-Silva, AméliaThe nutrient availability and supplementation of dietary phosphorus (P) and calcium (Ca) in avian feed, especially in laying hens, plays a vital role in phytase degradation and mineral utilization during the laying phase. The required concentration of P and Ca peaks during the laying phase, and the direct interaction between Ca and P concentration shrinks the availability of both supplements in the feed. Our goal was to characterize the active microbiota of the entire gastrointestinal tract (GIT) (crop, gizzard, duodenum, ileum, caeca), including digesta- and mucosa-associated communities of two contrasting high-yielding breeds of laying hens (Lohmann Brown Classic, LB; Lohmann LSL-Classic, LSL) under different P and Ca supplementation levels. Statistical significances were observed for breed, GIT section, Ca, and the interaction of GIT section x breed, P x Ca, Ca x breed and P x Ca x breed (p < 0.05). A core microbiota of five species was detected in more than 97% of all samples. They were represented by an uncl. Lactobacillus (average relative abundance (av. abu.) 12.1%), Lactobacillus helveticus (av. abu. 10.8%), Megamonas funiformis (av. abu. 6.8%), Ligilactobacillus salivarius (av. abu. 4.5%), and an uncl. Fusicatenibacter (av. abu. 1.1%). Our findings indicated that Ca and P supplementation levels 20% below the recommendation have a minor effect on the microbiota compared to the strong impact of the bird’s genetic background. Moreover, a core active microbiota across the GIT of two high-yielding laying hen breeds was revealed for the first time.Publication The AnimalAssociatedMetagenomeDB reveals a bias towards livestock and developed countries and blind spots in functional-potential studies of animal-associated microbiomes(2023) Avila Santos, Anderson Paulo; Kabiru Nata’ala, Muhammad; Kasmanas, Jonas Coelho; Bartholomäus, Alexander; Keller-Costa, Tina; Jurburg, Stephanie D.; Tal, Tamara; Camarinha-Silva, Amélia; Saraiva, João Pedro; Ponce de Leon Ferreira de Carvalho, André Carlos; Stadler, Peter F.; Sipoli Sanches, Danilo; Rocha, UlissesBackground: Metagenomic data can shed light on animal-microbiome relationships and the functional potential of these communities. Over the past years, the generation of metagenomics data has increased exponentially, and so has the availability and reusability of data present in public repositories. However, identifying which datasets and associated metadata are available is not straightforward. We created the Animal-Associated Metagenome Metadata Database (AnimalAssociatedMetagenomeDB - AAMDB) to facilitate the identification and reuse of publicly available non-human, animal-associated metagenomic data, and metadata. Further, we used the AAMDB to (i) annotate common and scientific names of the species; (ii) determine the fraction of vertebrates and invertebrates; (iii) study their biogeography; and (iv) specify whether the animals were wild, pets, livestock or used for medical research. Results: We manually selected metagenomes associated with non-human animals from SRA and MG-RAST. Next, we standardized and curated 51 metadata attributes (e.g., host, compartment, geographic coordinates, and country). The AAMDB version 1.0 contains 10,885 metagenomes associated with 165 different species from 65 different countries. From the collected metagenomes, 51.1% were recovered from animals associated with medical research or grown for human consumption (i.e., mice, rats, cattle, pigs, and poultry). Further, we observed an over-representation of animals collected in temperate regions (89.2%) and a lower representation of samples from the polar zones, with only 11 samples in total. The most common genus among invertebrate animals was Trichocerca (rotifers). Conclusion: Our work may guide host species selection in novel animal-associated metagenome research, especially in biodiversity and conservation studies. The data available in our database will allow scientists to perform meta-analyses and test new hypotheses (e.g., host-specificity, strain heterogeneity, and biogeography of animal-associated metagenomes), leveraging existing data. The AAMDB WebApp is a user-friendly interface that is publicly available at https://webapp.ufz.de/aamdb/ .Publication Assessing functional properties of diet protein hydrolysate and oil from fish waste on canine immune parameters, cardiac biomarkers, and fecal microbiota(2024) Cabrita, Ana R. J.; Barroso, Carolina; Fontes-Sousa, Ana Patrícia; Correia, Alexandra; Teixeira, Luzia; Maia, Margarida R. G.; Vilanova, Manuel; Yergaliyev, Timur; Camarinha-Silva, Amélia; Fonseca, António J. M.Locally produced fish hydrolysate and oil from the agrifood sector comprises a sustainable solution both to the problem of fish waste disposal and to the petfood sector with potential benefits for the animal’s health. This study evaluated the effects of the dietary replacement of mainly imported shrimp hydrolysate (5%) and salmon oil (3%; control diet) with locally produced fish hydrolysate (5%) and oil (3.2%) obtained from fish waste (experimental diet) on systemic inflammation markers, adipokines levels, cardiac function and fecal microbiota of adult dogs. Samples and measurements were taken from a feeding trial conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet and two periods of 6 weeks each. The experimental diet, with higher docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids contents, decreased plasmatic triglycerides and the activity of angiotensin converting enzyme, also tending to decrease total cholesterol. No effects of diet were observed on serum levels of the pro-inflammatory cytokines interleukin (IL)-1β, IL-8, and IL-12/IL-23 p40, and of the serum levels of the anti-inflammatory adipokine adiponectin. Blood pressure, heart rate and echocardiographic measurements were similar between diets with the only exception of left atrial to aorta diameter ratio that was higher in dogs fed the experimental diet, but without clinical relevance. Diet did not significantly affect fecal immunoglobulin A concentration. Regarding fecal microbiome, Megasphaera was the most abundant genus, followed by Bifidobacterium , Fusobacterium , and Prevotella , being the relative abundances of Fusobacterium and Ileibacterium genera positively affected by the experimental diet. Overall, results from the performed short term trial suggest that shrimp hydrolysate and salmon oil can be replaced by protein hydrolysate and oil from fish by-products without affecting systemic inflammatory markers, cardiac structure and function, but potentially benefiting bacterial genera associated with healthy microbiome. Considering the high DHA and EPA contents and the antioxidant properties of fish oil and hydrolysate, it would be worthwhile in the future to assess their long-term effects on inflammatory markers and their role in spontaneous canine cardiac diseases and to perform metabolomic and metagenomics analysis to elucidate the relevance of microbiota changes in the gut.Publication Complex European invasion history of Anoplophora glabripennis (Motschulsky): new insights in its population genomic differentiation using genotype-by-sequencing(2024) Haeussermann, Iris; Hasselmann, Martin; Haeussermann, Iris; Institute of Animal Science, Department of Livestock Population Genomics, Centre for Biodiversity and Integrative Taxonomy (KomBioTa), University of Hohenheim, Stuttgart, Germany; Hasselmann, Martin; Institute of Animal Science, Department of Livestock Population Genomics, Centre for Biodiversity and Integrative Taxonomy (KomBioTa), University of Hohenheim, Stuttgart, GermanyAnthropogenic activities like trade facilitate increasing rates of biological invasions. Asian long-horned beetle (ALB), which is naturally distributed in eastern Asia (China, Korean peninsula), was introduced via wood packing materials (WPM) used in trade to North America (1996) and Europe (2001). We used 7810 single nucleotide polymorphisms (SNPs) derived by a genotype-by-sequencing (GBS) approach to decipher the introduction patterns into Europe. This is applied for the first time on European ALB outbreaks from Germany, Switzerland, and Italy, both from still active and already eradicated infestations. The genome-wide SNPs detected signs of small and highly structured populations within Europe, showing clear founder effects. The very high population differentiation is presumably derived from multiple independent introductions to Europe, which are spatially restricted in mating. By admixture and phylogenetic analyses, some cases of secondary dispersal were observed. Furthermore, some populations suggest admixture, which might have been originated by either multiple introductions from different sources into the new sites or recurrent introductions from an admixed source population. Our results confirmed a complex invasion history of the ALB into Europe and the usability of GBS obtained SNPs in invasion science even without source populations.Publication Composition of the ileum microbiota is a mediator between the host genome and phosphorus utilization and other efficiency traits in Japanese quail (Coturnix japonica)(2022) Haas, Valentin; Vollmar, Solveig; Preuß, Siegfried; Rodehutscord, Markus; Camarinha-Silva, Amélia; Bennewitz, JörnBackground: Phosphorus is an essential nutrient in all living organisms and, currently, it is the focus of much attention due to its global scarcity, the environmental impact of phosphorus from excreta, and its low digestibility due to its storage in the form of phytates in plants. In poultry, phosphorus utilization is influenced by composition of the ileum microbiota and host genetics. In our study, we analyzed the impact of host genetics on composition of the ileum microbiota and the relationship of the relative abundance of ileal bacterial genera with phosphorus utilization and related quantitative traits in Japanese quail. An F2 cross of 758 quails was genotyped with 4k genome-wide single nucleotide polymorphisms (SNPs) and composition of the ileum microbiota was characterized using target amplicon sequencing. Heritabilities of the relative abundance of bacterial genera were estimated and quantitative trait locus (QTL) linkage mapping for the host was conducted for the heritable genera. Phenotypic and genetic correlations and recursive relationships between bacterial genera and quantitative traits were estimated using structural equation models. A genomic best linear unbiased prediction (GBLUP) and microbial (M)BLUP hologenomic selection approach was applied to assess the feasibility of breeding for improved phosphorus utilization based on the host genome and the heritable part of composition of the ileum microbiota. Results: Among the 59 bacterial genera examined, 24 showed a significant heritability (nominal p ≤ 0.05), ranging from 0.04 to 0.17. For these genera, six genome-wide significant QTL were mapped. Significant recursive effects were found, which support the indirect host genetic effects on the host’s quantitative traits via microbiota composition in the ileum of quail. Cross-validated microbial and genomic prediction accuracies confirmed the strong impact of microbial composition and host genetics on the host’s quantitative traits, as the GBLUP accuracies based on the heritable microbiota-mediated components of the traits were similar to the accuracies of conventional GBLUP based on genome-wide SNPs. Conclusions: Our results revealed a significant effect of host genetics on composition of the ileal microbiota and confirmed that host genetics and composition of the ileum microbiota have an impact on the host’s quantitative traits. This offers the possibility to breed for improved phosphorus utilization based on the host genome and the heritable part of composition of the ileum microbiota.Publication Cow’s microbiome from antepartum to postpartum: a long-term study covering two physiological challenges(2022) Tröscher-Mußotter, Johanna; Deusch, Simon; Borda-Molina, Daniel; Frahm, Jana; Dänicke, Sven; Camarinha-Silva, Amélia; Huber, Korinna; Seifert, JanaLittle is known about the interplay between the ruminant microbiome and the host during challenging events. This long-term study investigated the ruminal and duodenal microbiome and metabolites during calving as an individual challenge and a lipopolysaccharide-induced systemic inflammation as a standardized challenge. Strong inter- and intra-individual microbiome changes were noted during the entire trial period of 168 days and between the 12 sampling time points. Bifidobacterium increased significantly at 3 days after calving. Both challenges increased the intestinal abundance of fiber-associated taxa, e.g., Butyrivibrio and unclassified Ruminococcaceae. NMR analyses of rumen and duodenum samples identified up to 60 metabolites out of which fatty and amino acids, amines, and urea varied in concentrations triggered by the two challenges. Correlation analyses between these parameters indicated a close connection and dependency of the microbiome with its host. It turns out that the combination of phylogenetic with metabolite information supports the understanding of the true scenario in the forestomach system. The individual stages of the production cycle in dairy cows reveal specific criteria for the interaction pattern between microbial functions and host responses.Publication Defining valid breeding goals for animal breeds(2023) Wellmann, Robin; Gengler, Nicolas; Bennewitz, Jörn; Tetens, JensBackground: The objective of any valid breeding program is to increase the suitability of a breed for its future purposes. The approach most often followed in animal breeding for optimizing breeding goals assumes that the sole desire of the owners is profit maximization. As this assumption is often violated, a generalized approach is needed that does not rely on this assumption. Results: The generalized approach is based on the niche concept. The niche of a breed is a set of environments in which a small population of the breed would have a positive population growth rate. Its growth rate depends on demand from prospective consumers and supply from producers. The approach involves defining the niche that is envisaged for the breed and identifying the trait optima that maximize the breed’s adaptation to its envisaged niche within the set of permissible breeding goals. The set of permissible breeding goals is the set of all potential breeding goals that are compatible with animal welfare and could be reached within the planning horizon of the breeding program. In general, the breed’s adaptation depends on the satisfaction of the producers with the animals and on the satisfaction of the consumers with the products produced by the animals. When consumers buy live animals, then the breed needs to adapt to both the environments provided by the producers, and the environments provided by the consumers. The profit function is replaced by a more general adaptedness function that measures the breed’s adaptation to its envisaged niche. Conclusions: The proposed approach coincides with the traditional approach if the producers have the sole desire to maximize their income, and if consumer preferences are well reflected by the product prices. If these assumptions are not met, then the traditional approach to breeding goal optimization is unlikely to result in a valid breeding goal. Using the example of companion breeds, this paper shows that the proposed approach has the potential to fill the gap.Publication Expression of fibroblast growth factor 23 (FGF23) and αKlotho in two commercial laying hen strains fed with and without dietary mineral P supplements before and after the onset of the laying phase(2025) Meier, Leonie; Wallauch, Nadine; Feger, Martina; Oster, Michael; Sommerfeld, Vera; Schmucker, Sonja; Wimmers, Klaus; Huber, Korinna; Stefanski, Volker; Rodehutscord, Markus; Föller, MichaelMaintenance of phosphate homeostasis is particularly critical in laying hens for bone formation and calcium mobilization. The supplementation of their feed with mineral phosphate is common although recent research questions the usual levels of supplementation. Phosphate homeostasis is classically regulated by active vitamin D (calcitriol) and parathyroid hormone, whereas fibroblast growth factor 23 (FGF23) and its co-receptor αKlotho are novel factors. FGF23 has emerged as an important disease biomarker and αKlotho as an anti-aging factor in mammals, however, little is known about their role in poultry. Here, we studied FGF23 and αKlotho expression in two commercial laying hen strains under conditions of dietary mineral phosphorus renunciation and sufficient phosphorus supply. Fifteen- and 20-week-old Lohmann Brown-Classic (LB) or LSL-Classic (LSL) hens were fed a standard maize-soybean-based diet containing 0 or 1 g/kg additional mineral phosphorus for 4 weeks. The animals were sacrificed, and gene expression studied in different organs by quantitative real-time PCR and protein expression by western blotting. Statistical correlation with further parameters of mineral metabolism was analyzed by Pearson’s correlation coefficient or Spearman’s Rho. As a result, FGF23 bone expression was significantly lower and hepatic FGF23 expression higher in 24-week-old than in 19-week-old hens. Bone, hepatic, and renal αKlotho expression was significantly higher in older than younger animals. Compared to LB hens, LSL hens exhibited higher hepatic αKlotho irrespective of diet and age. Dietary phosphorus content did not significantly affect FGF23 and αKlotho expression. Bone FGF23 expression was positively and hepatic FGF23 negatively associated with plasma phosphate concentration whereas bone FGF23 expression was negatively and hepatic FGF23 positively associated with plasma calcitriol concentration. To conclude, we uncovered a strong impact of age and strain on FGF23 and αKlotho expression in two high performance laying hen strains, effects possibly associated with initiation of the egg-laying phase. Moreover, the regulation of hepatic FGF23 expression differed from the regulation of bone FGF23 expression. Further studies are needed to elucidate the physiological relevance.Publication Fecal cortisol metabolites indicate increased stress levels in horses during breaking-in: a pilot study(2025) Krieber, Julia; Nowak, Aurelia C.; Geissberger, Jakob; Illichmann, Oliver; Macho-Maschler, Sabine; Palme, Rupert; Dengler, Franziska; Madigan, JohnSport horses are frequently exposed to situations that were identified as stressors, indicated by an increased cortisol release, which might impair animal welfare. However, while many studies deal with the impact of exercise, transport, and competition on stress in horses, little is known about the early phase of a horse’s sports career and studies investigating the stress level of young horses during breaking-in are limited. To compare stress levels in unridden horses, horses during breaking-in, and horses in training we collected fecal samples of young, unridden horses ( n = 28) and of horses in different training stages ( n = 13) and measured fecal cortisol metabolite (FCM) concentrations. Our preliminary results showed that FCM concentrations of unridden horses were significantly lower than those of horses in training (Mann–Whitney rank sum test, p < 0.001). Particularly in the first year under the saddle FCMs were significantly higher than in unridden horses (one way ANOVA + post hoc Holm–Sidak test, p < 0.05), with a tendency for FCM levels to decrease with time in training. Furthermore, we observed that within the group of ridden horses there was a larger range of variability in FCM levels, suggesting individual variations regarding their ability to deal with (training-induced) stress. These results indicate that breaking-in is a stressful time for young horses, underlining the importance of carrying out the initial training as carefully as possible.Publication Food fermentation: an essential unit operation towards secure, sustainable, safe, and sustaining food systems(2025) Gänzle, Michael G.; Seifert, Jana; Weiss, Jochen; Zijlstra, Ruurd T.Publication Genomic dissection of the correlation between milk yield and various health traits using functional and evolutionary information about imputed sequence variants of 34,497 German Holstein cows(2024) Schneider, Helen; Krizanac, Ana-Marija; Falker-Gieske, Clemens; Heise, Johannes; Tetens, Jens; Thaller, Georg; Bennewitz, Jörn; Schneider, Helen; Institute of Animal Science, University of Hohenheim, 70599, Stuttgart, Germany; Krizanac, Ana-Marija; Department of Animal Sciences, University of Göttingen, 37077, Göttingen, Germany; Falker-Gieske, Clemens; Department of Animal Sciences, University of Göttingen, 37077, Göttingen, Germany; Heise, Johannes; Vereinigte Informationssysteme Tierhaltung w.V. (VIT), 27283, Verden, Germany; Tetens, Jens; Department of Animal Sciences, University of Göttingen, 37077, Göttingen, Germany; Thaller, Georg; Institute of Animal Breeding and Husbandry, Christian-Albrechts University of Kiel, 24098, Kiel, Germany; Bennewitz, Jörn; Institute of Animal Science, University of Hohenheim, 70599, Stuttgart, GermanyBackground: Over the last decades, it was subject of many studies to investigate the genomic connection of milk production and health traits in dairy cattle. Thereby, incorporating functional information in genomic analyses has been shown to improve the understanding of biological and molecular mechanisms shaping complex traits and the accuracies of genomic prediction, especially in small populations and across-breed settings. Still, little is known about the contribution of different functional and evolutionary genome partitioning subsets to milk production and dairy health. Thus, we performed a uni- and a bivariate analysis of milk yield (MY) and eight health traits using a set of ~34,497 German Holstein cows with 50K chip genotypes and ~17 million imputed sequence variants divided into 27 subsets depending on their functional and evolutionary annotation. In the bivariate analysis, eight trait-combinations were observed that contrasted MY with each health trait. Two genomic relationship matrices (GRM) were included, one consisting of the 50K chip variants and one consisting of each set of subset variants, to obtain subset heritabilities and genetic correlations. In addition, 50K chip heritabilities and genetic correlations were estimated applying merely the 50K GRM. Results: In general, 50K chip heritabilities were larger than the subset heritabilities. The largest heritabilities were found for MY, which was 0.4358 for the 50K and 0.2757 for the subset heritabilities. Whereas all 50K genetic correlations were negative, subset genetic correlations were both, positive and negative (ranging from -0.9324 between MY and mastitis to 0.6662 between MY and digital dermatitis). The subsets containing variants which were annotated as noncoding related, splice sites, untranslated regions, metabolic quantitative trait loci, and young variants ranked highest in terms of their contribution to the traits’ genetic variance. We were able to show that linkage disequilibrium between subset variants and adjacent variants did not cause these subsets’ high effect. Conclusion: Our results confirm the connection of milk production and health traits in dairy cattle via the animals’ metabolic state. In addition, they highlight the potential of including functional information in genomic analyses, which helps to dissect the extent and direction of the observed traits’ connection in more detail.Publication Mapping genes for resilient dairy cows by means of across-breed genome-wide association analysis(2025) Keßler, Franziska; Zölch, Maximilian; Wellman, Robin; Bennewitz, Jörn; Keßler, Franziska; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Zölch, Maximilian; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Wellman, Robin; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Bennewitz, Jörn; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, GermanyBackground: Indicator traits based on variance and autocorrelation of longitudinal data are increasingly used to measure resilience in animal breeding. While these traits show promising heritability and can be routinely collected, their genetic architecture remains poorly understood. We conducted GWAS for three resilience indicators across German Holstein ( n = 2,300), Fleckvieh ( n = 2,330), and Brown Swiss ( n = 1,073) dairy cattle ( Bos Taurus ) populations. The indicators included variance ( ) and autocorrelation ( ) of deviations of observed from predicted daily milk yield and variance of relative daily milk yield ( ). Additionally, we analysed a selection index combining these traits. Prior to GWAS, we examined population structure through multi-dimensional scaling (MDS) and LD patterns, revealing distinct genetic clusters for each breed and similar LD decay patterns. Results: The GWAS results confirmed the polygenic nature of resilience, with multiple genomic regions showing significant associations. Notable signals were detected on BTA5 ( ), BTA14 ( ), BTA2 and BTA8 ( ) for single indicator traits. For selection index resilience, strong suggestive SNPs are located on BTA4 , BTA16 , BTA21 , and BTA27 . Detected regions overlapped with previously reported QTLs for performance, reproduction, longevity and health, providing new insights into the biological pathways underlying dairy cattle resilience. Conclusions: Our findings demonstrate that resilience indicators have a complex genetic architecture with both breed-specific and shared components, supporting their potential use in selective breeding programs while highlighting the importance of careful trait definition.Publication Mendelian randomization analysis of 34,497 German Holstein cows to infer causal associations between milk production and health traits(2024) Schneider, Helen; Haas, Valentin; Krizanac, Ana-Marija; Falker-Gieske, Clemens; Heise, Johannes; Tetens, Jens; Thaller, Georg; Bennewitz, JörnBackground: Claw diseases and mastitis represent the most important health issues in dairy cattle with a frequently mentioned connection to milk production. Although many studies have aimed at investigating this connection in more detail by estimating genetic correlations, they do not provide information about causality. An alternative is to carry out Mendelian randomization (MR) studies using genetic variants to investigate the effect of an exposure on an outcome trait mediated by genetic variants. No study has yet investigated the causal association of milk yield (MY) with health traits in dairy cattle. Hence, we performed a MR analysis of MY and seven health traits using imputed whole-genome sequence data from 34,497 German Holstein cows. We applied a method that uses summary statistics and removes horizontal pleiotropic variants (having an effect on both traits), which improves the power and unbiasedness of MR studies. In addition, genetic correlations between MY and each health trait were estimated to compare them with the estimates of causal effects that we expected. Results: All genetic correlations between MY and each health trait were negative, ranging from − 0.303 (mastitis) to − 0.019 (digital dermatitis), which indicates a reduced health status as MY increases. The only non-significant correlation was between MY and digital dermatitis. In addition, each causal association was negative, ranging from − 0.131 (mastitis) to − 0.034 (laminitis), but the number of significant associations was reduced to five nominal and two experiment-wide significant results. The latter were between MY and mastitis and between MY and digital phlegmon. Horizontal pleiotropic variants were identified for mastitis, digital dermatitis and digital phlegmon. They were located within or nearby variants that were previously reported to have a horizontal pleiotropic effect, e.g., on milk production and somatic cell count. Conclusions: Our results confirm the known negative genetic connection between health traits and MY in dairy cattle. In addition, they provide new information about causality, which for example points to the negative energy balance mediating the connection between these traits. This knowledge helps to better understand whether the negative genetic correlation is based on pleiotropy, linkage between causal variants for both trait complexes, or indeed on a causal association.Publication 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, AndreasRoe 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.Publication Occurrence and quantification of porcine hemotrophic mycoplasmas in blood-sucking Stomoxys calcitrans(2025) Arendt, Mareike; Hoelzle, Katharina; Stadler, Julia; Ritzmann, Mathias; Ade, Julia; Hoelzle, Ludwig E.; Schwarz, Lukas; Rossi, FrancaHemotrophic mycoplasmas (HMs) are cell wall-less, small and uncultivable pathogens, which can cause infections in pigs with no to severe clinical signs and can contribute to significant economic losses in the pig industry. In addition to the known mechanical transmission routes of HMs (e.g., via blood-contaminated instruments or lesions from ranking fights), transmission to pigs by arthropod vectors such as Stomoxys calcitrans is being discussed. To date, there is scant available data concerning the transmission of HMs by stable flies. The objective of this study is to gain more data concerning the occurrence of HMs in Stomoxys calcitrans . Therefore, quantitative real-time PCR was conducted on different stable fly samples (surface washings and whole flies). We found Mycoplasma ( M. ) suis in 5.2% of crushed flies and 4.2% of fly wash solutions, and M. parvum was detected in 5.2% of flies and 9.4% of fly wash solutions. ‘ Candidatus ( Ca .) M. haemosuis’ was not detected in any sample. The mean bacterial loads were 2.0 × 10 2 M. suis /fly, 9.3 × 10 2 M. suis /fly wash solution and, for M. parvum , 2.4 × 10 3 M. parvum /fly and 2.1 × 10 3 M. parvum /fly wash solution. This molecular occurrence of porcine HMs in blood-sucking flies and reasonable bacterial loads in the two- to three-digit range demonstrate that these flies serve as mechanical vectors in stables and are, therefore, of epidemiological importance.Publication Occurrence of ‘Candidatus Mycoplasma haemosuis’ in fattening pigs, sows and piglets in Germany using a novel gap-based quantitative real-time PCR assay(2022) Ade, Julia; Stadler, Julia; Ritzmann, Mathias; Zübert, Christina; Hoelzle, Katharina; Hoelzle, Ludwig E.Background: The appearance of the novel porcine haemotrophic mycoplasma (HM) species ‘Candidatus Mycoplasma haemosuis’ was reported in apparently healthy but also in clinically sick animals in China, Korea and in a case report from Germany. Outside of Asia, however, nothing further is known about the frequency of ‘Ca. M. haemosuis’ in pigs to date. To investigate the distribution of this novel HM species in Germany, fattening pigs, sows and pre-suckling piglets were examined using a herein developed quantitative real-time PCR assay (qPCR). Because the piglets were sampled before the first colostrum uptake, additional information on a possible vertical transmission from dams to their offspring was obtained. Results: Our novel qPCR assay successfully detected ‘Ca. M. haemosuis’ in all blood samples from the ‘Ca. M. haemosuis’-infected pigs. No cross-reactivity was detected when DNA from non-target Mycoplasma spp. and other bacterial species representing 105 bacteria/reaction were used as a template. The lower limit of detection of the qPCR was thus 10 gap gene copies per reaction and 2.5 x 103 genome equivalents (GE) per mL blood. ‘Candidatus M. haemosuis’ was detected by this qPCR in blood samples from a total out of 6.25% sows (13/208), 4.50% pre-suckling piglets (28/622) and 17.50% fattening pigs (35/200). On farm level, 3 out of 21 piglet producing farms (14.28%) and 9 out of 20 fattening farms (45.00%) were positive for ‘Ca. M. haemosuis’. Co-infections with M. suis were evident in all age groups. Conclusion: ‘Candidatus M. haemosuis’ infection is present in German pig farms and the detection of the novel porcine HM species in piglets immediately after birth before colostrum intake indicates vertical transmission. The novel qPCR assay specific for ‘Ca. M. haemosuis’ described herein will be a prerequisite for future studies on the prevalence, epidemiology as well as the clinical and economic impact of ‘Ca. M. haemosuis’ infections.Publication The potential of gene editing and genomic selection in improving quantitative traits: A simulation study regarding dual-purpose chicken(2024) Chuang, Edward; Bennewitz, JörnThe practice of chick culling is the killing of day-old chicks of the layer line chicken. Because of their inability to lay eggs and inefficiency to grow meat, killing them instead of raising them is more economically efficient. In recent years, this practice has raised ethical concerns and led to the ban of this practice in several countries, including Germany and France. One of the several possible solutions is the use of dual-purpose chicken. Unlike the commercial layers, the dual-purpose chicken has abilities in both egg laying and meat production. Even though dual-purpose chicken has better meat growth performance compared to the commercial layers, the use of dual-purpose chicken is still challenging. One of the major challenges to improve dual-purpose chicken is the negative correlation between egg production and meat production. To cope with this negative correlation, some have proposed that gene editing could be a helpful tool to mitigate the problem. The aim of this simulation study is to explore the potential of gene editing to improve negatively correlated quantitative traits. To be more specific, given the aforementioned reasons, the negative correlation between the meat and egg production traits in chicken was chosen as the topic of this study. That is, chicken breeding programs that develop and improve dual-purpose chicken were simulated to discuss the potential of gene editing in animal breeding programs. Chapter 1 begins this thesis with a general introduction of the background to the problem of chick culling, the challenge of developing dual-purpose chicken, and the use of gene editing. Some previous simulation studies on the use of gene editing to improve quantitative traits in animal breeding programs is also introduced in this chapter. Chapter 2 presents a literature review that discusses how gene editing technologies could change the breeding and production of farm animals. In accordance with this thesis's aim, a specific focus was placed on improving quantitative traits. By reviewing the technical and social limitations of gene editing, this review provides a basis for further discussion of the feasibility of the gene-editing implementation as presented in the next chapters. Chapter 3 introduces the simulation framework to explore the potential of gene editing in chicken breeding programs. This framework first simulates two divergently selected lines that reflect the commercial layers and broilers. Based on these two lines, two alternative breeding programs were simulated. One is to develop a dual-purpose line from a layer line (the L-Pure Scenario), while the other selects and improves a synthetic line obtained from a cross between a layer line and a broiler line (the L-B cross scenario). In both breeding schemes, gene editing was integrated into the genomic selection scheme applying optimal contribution selection. The simulation presented in Chapter 4 considers multiplex genome editing that could edit five to one hundred single nucleotide variants at a time. These variants include the causal variants and other falsely edited variants. The results suggest that multiplex gene editing is beneficial in both the L-Pure and the L-B cross scenarios. It also demonstrated that when the risk of negative off-target effect exists, editing more nucleotides does not guarantee extra genetic gain. The simulation presented in Chapter 5 considers the introduction of major genes that would have larger effects on meat production. Here, only the L-Pure scenario is considered. Different to Chapter 4, in this chapter, editing is only possible with only one gene at a time. This chapter aims to study the effects of the numbers of major genes and the pleiotropy (on egg production and meat production). The results suggest that gene editing would be beneficial in dual-purpose chicken breeding programs when the gene is mildly pleiotropic. Chapter 6 ends the thesis with a general discussion that covers the limitations of this study and the possibilities to further expand the simulation study.Publication Structural variants and tandem repeats in the founder individuals of four F2 pig crosses and implications to F2 GWAS results(2022) Blaj, Iulia; Tetens, Jens; Bennewitz, Jörn; Thaller, Georg; Falker-Gieske, ClemensBackground: Structural variants and tandem repeats are relevant sources of genomic variation that are not routinely analyzed in genome wide association studies mainly due to challenging identification and genotyping. Here, we profiled these variants via state-of-the-art strategies in the founder animals of four F2 pig crosses using whole-genome sequence data (20x coverage). The variants were compared at a founder level with the commonly screened SNPs and small indels. At the F2 level, we carried out an association study using imputed structural variants and tandem repeats with four growth and carcass traits followed by a comparison with a previously conducted SNPs and small indels based association study. Results: A total of 13,201 high confidence structural variants and 103,730 polymorphic tandem repeats (with a repeat length of 2-20 bp) were profiled in the founders. We observed a moderate to high (r from 0.48 to 0.57) level of co-localization between SNPs or small indels and structural variants or tandem repeats. In the association step 56.56% of the significant variants were not in high LD with significantly associated SNPs and small indels identified for the same traits in the earlier study and thus presumably not tagged in case of a standard association study. For the four growth and carcass traits investigated, many of the already proposed candidate genes in our previous studies were confirmed and additional ones were identified. Interestingly, a common pattern on how structural variants or tandem repeats regulate the phenotypic traits emerged. Many of the significant variants were embedded or nearby long non-coding RNAs drawing attention to their functional importance. Through which specific mechanisms the identified long non-coding RNAs and their associated structural variants or tandem repeats contribute to quantitative trait variation will need further investigation. Conclusions: The current study provides insights into the characteristics of structural variants and tandem repeats and their role in association studies. A systematic incorporation of these variants into genome wide association studies is advised. While not of immediate interest for genomic prediction purposes, this will be particularly beneficial for elucidating biological mechanisms driving the complex trait variation.Publication Subconjunctival bleedings in neonatal calves: a case series report(2022) Steffl, Martin; Nautscher, NadineBackground: In animals, only few reports exist about the occurrence and causes of subconjunctival bleedings, especially in newborn calves. Most case reports and studies showed that the major risk factors for subconjunctival bleedings in animals are traumatic events such as birth trauma and traffic accidents, respectively. In neonatal babies, it is suggested that compression of the thorax and abdomen during delivery or forces generated in utero during labor may raise venous pressure to conjunctival vessels and can cause subconjunctival bleedings. Results: The incidence of bleedings in neonatal Holstein–Friesian calves was 2.4 per cent of 289 neonatal calves examined over a six-year period. In general, two types of subconjunctival bleedings were seen. One was usually in a semilunar fashion immediately outside the limbus of the eye. The other type was a stripe or macule of variable size at different positions of the sclera. The subconjunctival bleedings were not related to gestational time. In all cases, affected calves were born without assistance. Multiparous cows were more often involved in the calves with subconjunctival bleedings. Two calves examined haematologically did not show signs of anemia or thrombocytopenia. Conclusions: Subconjunctival bleedings in neonatal calves appear not to be incidental findings. Main causes or associated conditions of subconjunctival bleedings were not found.Publication Transcriptional responses in jejunum of two layer chicken strains following variations in dietary calcium and phosphorus levels(2021) Reyer, Henry; Oster, Michael; Ponsuksili, Siriluck; Trakooljul, Nares; Omotoso, Adewunmi O.; Iqbal, Muhammad A.; Muráni, Eduard; Sommerfeld, Vera; Rodehutscord, Markus; Wimmers, KlausBackground: Calcium (Ca) and phosphorus (P) are essential nutrients that are linked to a large array of biological processes. Disturbances in Ca and P homeostasis in chickens are associated with a decline in growth and egg laying performance and environmental burden due to excessive P excretion rates. Improved utilization of minerals in particular of P sources contributes to healthy growth while preserving the finite resource of mineral P and mitigating environmental pollution. In the current study, high performance Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) hens at peak laying performance were examined to approximate the consequences of variable dietary Ca and P supply. The experimental design comprised four dietary groups with standard or reduced levels of either Ca or P or both (n = 10 birds per treatment group and strain) in order to stimulate intrinsic mechanisms to maintain homeostasis. Jejunal transcriptome profiles and the systemic endocrine regulation of mineral homeostasis were assessed (n = 80). Results: Endogenous mechanisms to maintain mineral homeostasis in response to variations in the supply of Ca and P were effective in both laying hen strains. However, the LSL and LB appeared to adopt different molecular pathways, as shown by circulating vitamin D levels and strain-specific transcriptome patterns. Responses in LSL indicated altered proliferation rates of intestinal cells as well as adaptive responses at the level of paracellular transport and immunocompetence. Endogenous mechanisms in LB appeared to involve a restructuring of the epithelium, which may allow adaptation of absorption capacity via improved micro-anatomical characteristics. Conclusions: The results suggest that LSL and LB hens may exhibit different Ca, P, and vitamin D requirements, which have so far been neglected in the supply recommendations. There is a demand for trial data showing the mechanisms of endogenous factors of Ca and P homeostasis, such as vitamin D, at local and systemic levels in laying hens.
