Browsing by Subject "Alter"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Publication
    Analysis of aging-related changes and influencing factors on the metabolome of beef
    (2023) Bischof, Greta; Gibis, Monika
    Aging of beef is necessary to improve its flavor and tenderness. There are two most common aging types, dry-aging and wet-aging. Dry-aged beef is often associated with a higher eating quality than wet-aged beef. The term “dry-aged beef” is not legally defined, so authentication methods are needed to protect the consumers from food fraud. During beef aging, the metabolome of beef changes due to the postmortem metabolism. This dissertation focuses on the aging method as a postmortem process and the resulting changes in the metabolome. As a hypothesis of this study, it was postulated that the detection of these metabolic changes due to aging of beef is feasible by 1H NMR spectroscopy and based on these measurements the evaluation of an authentication model for the aging method of beef is possible. In order to test this hypothesis, a sample preparation and measurement method was developed and based on this, potential influencing factors such as sampling position in muscle, breed and sex were investigated on the metabolome of fresh and aged beef. In the first part of this thesis, the sample preparation and the 1H NMR measurement method were developed. In the sample preparation, the polar fraction of the metabolome was extracted from 200 mg of beef, allowing 24 samples to be prepared in parallel. The sample preparation and the measurement method were validated, and the first aged beef samples were analyzed to check if the aging-related changes in the metabolome could be detected by this method. In the second part of this thesis, the sampling position in the muscle were analyzed for changes or differences in the metabolome due to its location in the muscle. The results showed that the metabolome changes along the length of the M. longissimus thoracis et lumborum, but the influence of the aging type and aging time was more pronounced in the metabolome of beef. The comparison of the surface and the inner part of wet-aged and dry-aged beef showed that the metabolome of dry-aged beef differed greatly between the surface and the inner part, despite the exclusion of the moisture content by freeze-drying and the low microbial load. There were only slight differences between the surface and the inner part for wet-aged beef, which could be due to the influence of microbiota and their metabolites. Therefore, the sampling location in the M. longissimus thoracis et lumborum was determined as precisely as possible for the further studies. The muscles were cut into ten pieces from cranial to caudal and dry-aged or wet-aged for 0, 7, 14, 21, and 28 days, in duplicates. The third part of this thesis focuses on the potential influencing factors such as breed and sex of the animals. Fresh and aged beef samples from three cattle types (heifer, cow, and young bull) and two different breeds (‘Fleckvieh’ and ‘Schwarzbunt’) were analyzed by targeted and non-targeted 1H NMR spectroscopy. Both factors were shown to influence the metabolome of fresh and aged beef. Therefore, these factors had to be included in the authentication model based on both targeted and non-targeted model. The calculation of the authentication model was the main part of this thesis and showed a good prediction of cattle type, breed, aging time and aging type of beef. The authentication model was based on the combination of multiple models of PLS-R and PLS-DA. The model for predicting the cattle type showed an accuracy of 99 %, and the models for predicting the breed depending on the cattle type showed an accuracy of 100 %. Aging time could be predicted with an error of 2.28 days. The statistical models for aging type were separated by aging time based on the determination of aging time. The model for predicting the aging type of 28-day aged samples had an accuracy of 99 %. The other statistical models for predicting aging type were additionally separated by cattle type and breed, and their accuracy ranged from 90 % to 100 %. In conclusion, an authentication model to determine the cattle type, breed, aging time and aging type of beef was developed in this dissertation. Therefore, it is possible to authenticate beef samples using a single 1H NMR spectrum. In future studies, it would be useful to extend this authentication model to other samples of other breeds and influencing factors.
  • Thumbnail Image
    Publication
    Comprehensive characterization of microbiota in the gastrointestinal tract of quails and two high yielding laying hen breeds
    (2023) Roth, Christoph Florian; Camarinha-Silva, Amélia
    The microbiomes composition in the gastrointestinal tract (GIT) is subject to several changes and influences. In addition to breed, sex, or diet, age affects the GIT microbiome dynamics of laying hens and quails. From the first day, the microbiome develops and increases its bacterial load to thousands of species. Then, depending on the diet fed, the animals microbiome and associated active bacteria vary and directly influence the animals nutrient uptake and efficiency. Omics technologies give insights into changes in microbes in the GIT (crop, gizzard, duodenum, ileum, caeca). In addition, they can reveal how feed supplements such as calcium (Ca) or phosphorus (P) can affect host health and performance through alterations in the microbiome. The Japanese quail has been an established animal model for nutritional and biological studies in poultry for the last 60 years. In particular, its short development time makes it a convenient model for microbiome research. However, compared to broiler microbiome research, the quail microbiome is still poorly understood. Animals of the breed Coturnix japonica were housed under the same conditions, fed a diet with P below recommendation, and the ileum microbiota characterized. Microbiota relations with gender and higher or lower predisposition of the birds for PU, CaU, FI, BWG, and FC were described (Chapter II). In addition, these performance parameters influenced the relative average abundance of bacteria like Candidatus Arthromitus, Bacillus, and Leuconostoc. Gender affects specific bacterial groups of the GIT, such as Lactobacillus, Streptococcus, Escherichia, and Clostridium, which differ in average abundance between male and female quails. Despite the comprehensive microbiota analysis, the interplay between animal genetics, diet, sex, and microbiome functionality is not yet understood. The laying hen breeds Lohmann LSL-Classic and Lohmann Brown-Classic are used worldwide. Little is known about the interaction with microbiome composition, performance, dietary effects, and changes during the productive life that might help develop feeding strategies and microbiome responses on a large scale. Because of the importance of P and Ca in poultry diet, the research in Chapter III was conducted to challenge laying hens with reduced dietary P and Ca and describe the effect on GIT active microbiota. The breed was the primary driver of microbial differences. A core microbiome of active bacteria, present along the complete GIT, was revealed for the first time and consisted of five bacteria detected in 97% of all samples, including digesta and mucosa samples (uncl. Lactobacillus, Megamonas funiformis, Ligilactobacillus salivarius, Lactobacillus helveticus, uncl. Fuscatenibacter). Furthermore, significant microbial differences between the GIT sections and between the breeds were described. Minor dietary effects of the P and Ca reduction on the microbiota showed that a further decrease in Ca and P supplementation might be possible without affecting the gut microbial composition and bird performance. Furthermore, the microbiome of laying hens was characterized at five productive stages (weeks 10, 16, 24, 30, and 60) to analyze the age effect on the GIT microbiome (Chapter IV). Although the two breeds of laying hens were offered the same diet and housed under similar conditions, the active microbiota composition changed between the analyzed productive stages, the breed and the GIT sections. The major shift occurred between weeks 16 and 24 and supported the hypothesis of bacterial fluctuations due to the onset of the laying period. Those changes occurred mainly in the abundance of the genera Lactobacillus and Ligilactobacillus. However, it remains unclear whether the dietary changes, due to the development of the birds, influenced the microbiota shifts or if the anatomical and physiological modifications influenced the GIT microbiota. Furthermore, the shotgun metagenomic analysis revealed differences in regulatory functions and pathways between breeds, sections, and the two production stages. Different relative abundance levels of the microbial composition were observed between the RNA-based targeted sequencing and the DNA-based shotgun metagenomics. In conclusion, the comprehensive characterization of the microbiota in the GIT of quails and two high-yielding breeds of laying hens contributes to a broader knowledge of the microbiome dynamics within the fowl GIT. Age and breed play a more important role than diet in influencing the dynamics of microbial composition in laying hens, and individual performance and sex in quails. Research characterizing the microbiome in poultry and its effect on diet and host genetics will help improve feeding and breeding strategies in the future and reduce excretion of nutrients into the environment while ensuring overall animal health.
  • Thumbnail Image
    Publication
    How does subjective well-being evolve with age? A literature review
    (2013) Sousa-Poza, Alfonso; Moeller, Valerie; López Ulloa, Beatriz Fabiola
    This literature review provides an overview of the theoretical and empirical research in several disciplines on the relation between ageing and subjective well-being, i.e., how subjective well-being evolves across the lifespan. Because of the different methodologies, data sets and samples used, comparison among disciplines and studies is difficult. However, extant studies do show either a U-shaped, inverted U-shaped or linear relation between ageing and subjective well-being.
  • Thumbnail Image
    Publication
    Impact of age and weaning time on the gut microbiome and the potential host-microbe interactions in calves
    (2021) Amin, Nida; Seifert, Jana
    The period from birth until the end of weaning is critical for calves as they undergo extreme stress caused by maternal separation, transportation, and weaning related dietary shifts, that can cause long-lasting effects on animal behaviour, health as well as future production parameters. Monitoring the development of microbial ecosystem throughout the gastrointestinal tract of calves and host-microbe interactions during the challenging life periods such as perinatal and weaning is essential for sustainable ruminant production. The present thesis provided new insight on the suitability of buccal swabs as an alternative to complex stomach tubing method for predictive analysis of rumen microbial communities. The changes in oral, rumen and faecal microbial community structure of female German Holstein calves from 8-days to 5-months of age as well as during early- and late-weaning event were identified. The oral microbiota plays a crucial role in animal health. A high dominance of oral pathogens was observed during the first 11-weeks of calves’ life. Similar to the oral microbiota, faeces of 8-day-old calves also showed high abundances of certain opportunistic pathogenic bacteria. Both oral and faecal pathogens showed a decrease in abundance with age and after weaning event in the earlyC group, indicating the age and weaning-dependent maturation of the host immune system. The establishment of dense microbial communities in the faeces of 8-day-old (experimental day 1) pooled herd milk and milk replacer fed Holstein calves was shown and it was dominated by phyla Firmicutes and Actinobacteria and potential lactose- and starch-degrading bacterial species, but as the calves aged and became more mature (5-months of age), their rumen and faecal bacterial communities were dominated by potential fibre-utilizing bacterial genera. The weaning related dietary transitions are critical for calves as their gastrointestinal tract undergoes several modifications, enabling them to digest plant-based diet during the postweaning period. Thus, it was proposed that the age at which animals should be weaned must be carefully considered as it clearly impacted the gastrointestinal tract microbial communities and plasma metabolic profiles of calves in the present study. Early introduction of roughages in the diet of 7-week-old calves increased the abundances of plant fiber degrading bacteria and decreased the abundances of potential lactose- and starch-degrading bacteria in the buccal cavity, rumen and faeces, indicating the weaning-related increase in fiber ingestion and the decrease in milk consumption of the early-weaned group. However, when roughages were introduced in the diet of late-weaned calves at 17-weeks of age, no significant modifications in the structure of gastrointestinal tract microbial communities were observed. Similar to the microbiome, plasma metabolic profiles of early-weaned calves during days 42–112, showed lower concentrations of most of the amino acids, few biogenic amines, and sphingomyelins as compared to the late-weaned calves, suggesting that the liquid diet could provide certain metabolites that can be transported into the bloodstream through gastrointestinal tract. Similarly, the weaning-dependent changes in the quantity of dietary protein, fat and carbohydrates resulted in substantial changes in amino acid metabolism of the early-weaned group. The early-weaning event not only impacted the host microbiome and metabolome but also the host-microbe metabolic interactions as the abundances of potential lactose- and starch degrading bacteria and plasma concentrations of amino acid, biogenic amines and sphingomyelins were strongly positively correlated, both were negatively impacted by the early-weaning event. Thus, it can be concluded that late-weaning was beneficial as it allowed better adaptability of microbes to weaning-related dietary shifts, perhaps due to the greater maturation of their gastrointestinal tract with age as compared to the early-weaning group.
  • Thumbnail Image
    Publication
    Older adults’ internet use, outdoor activity, and the urban environment : empirical analysis
    (2021) Schehl, Barbara; Kirn, Stefan
    In an ageing society, information technology (IT) can be a powerful tool to support older adults in staying physically, mentally, and socially active. A growing number of studies show positive effects of Internet use on active ageing. Specifically, understanding the relationship between older adults’ Internet use and their participation in outdoor activity has gained attention. However, little is known about the role of specific online activities, as previous research mainly considered general Internet use, e.g., writing emails and browsing the Web, which does not provide a rationale for increased outdoor activity. Another important factor affecting outdoor activity is the urban environment in which older adults live, especially as the environment can either motivate or hinder participation in outdoor activity. Against this backdrop, the aim of this thesis is to get a better understanding of the association between Internet use, the urban environment, and participation in outdoor activity. By adopting an ecological perspective, this dissertation is first in comprehensively assessing this association. Three studies provide empirical insights into patterns of factors and contribute an enhanced understanding of the association between older adults’ Internet use, the urban environment, and outdoor activity. In summary, this thesis contributes to a relevant growth of knowledge on older adults’ Internet use and outdoor activity. The approach in this thesis uncovered important differences in the roles of individual factors as well as environmental factors in explaining older adults’ outdoor activity. Based on this contributions, important implications for research can be identified. For instance, future research can use the conceptual framework as a basis to investigate further types of outdoor activities and further types of online activities, such as social networks and messaging services which attain increasing relevance for the group of older adults. Further, this dissertation also has some practical implications, for example, as all three studies showed that socio-demographic predictors play important different roles, the findings are specifically relevant to identify specific groups of older adults. For instance, developers and providers can tailor their services to the needs of older adults, e.g., by designing responsive and barrier-free interfaces that adapt to individual capabilities in cognition, vision, and motor function. Concluding, older adults should be encouraged to go online because the Internet increasingly provides information about opportunities and offerings in the city. The findings of this dissertation provide a rationale for the development of online services that offer neighborhood information and ultimately support older adults to be active outdoors.
  • Thumbnail Image
    Publication
    The effect of aging in the murine gut microbiome
    (2020) Hernández Arriaga, Angélica; Camarinha-Silva, Amélia
    Aging is characterized by several physiological changes. During the lifespan, the biological systems from the body of humans and other animals remain dynamic. Throughout the early stages of life, the microbiome develops into a complex ecosystem with thousands of species. Variations related to diet, environmental changes, medications affect the diversity and composition of the microbiota through the lifespan. Some old individuals with higher incidence of chronic diseases have a loss of the stability of the microbiome and an imbalance occurs between the different colonizers of the gut, also named dysbiosis. One of the most distinctive changes occurring with age is the prevalent low grade inflammation, which is named inflamm-aging. This not only changes the microbial composition of the GIT but also affects the permeability. Murine models are well established and help us to understand the complex dynamics between the host and the microbial communities inhabiting the gastrointestinal tract. These models allow us to analyze microbial communities from tissue and mucosa, from all sections of the gut, which is limited in humans. Methods standardization is an important topic in microbiome research. In chapter 2 it was compared the efficiency of two sample methods, cotton swab and tissue biopsy, in characterizing the mouth microbiota. In recent years, the mouth microbiome is being seen as a diagnostic tool for not only oral diseases but also systemic diseases. As physiological changes occur with aging, the microbiome from the mouth is affected and there is an increase of pathogens present in the oral surfaces. In murine models, cotton swab is a common tool used for sampling the microbiome of the oral cavity. In our study, we observed similar microbial community structure using both methodologies. However, the species Streptococcus danieliae, Moraxella osloensis, and some unclassified members of Streptococcus were affected by the different sampling procedures. In this trial, we included mice at two different ages, 2 months old being considered young and 15 months old considered middle aged mice. We observed changes in the genera Actinobacillus, Neisseria, Staphylococcus, and Streptococcus related to the age of the animal and the sampling type. These results showed the importance of sampling standardization in microbiome research and that age has a strong effect on the microbial ecology of the oral cavity. In chapter 3, it was studied the bacterial communities from duodenum and colon of mice at 2, 15, 24 and 30 months of age in combination with the results of the expression levels of antimicrobial peptides in small intestine and markers of intestinal barrier function. Besides, in this chapter were also assessed the indices of liver damage, inflammation and expression levels of lipopolysaccharide binding protein (Lbp) as well as of toll-like receptors (Tlr) 1-9 in liver tissues. At 24 and 30 months of age there was an increase in inflammation, they developed fibrosis and the levels of endotoxin in plasma were higher. Regarding changes in the microbiome, the duodenum had more changes than the colon related to age. Allobacullum, Bifidobacterium, Olsenella, Corynebacterium were the genera that differed statistically in the duodenum through the murine lifespan. Fewer changes were observed in the colon, as Allobaculum was the only genus that showed differences between young and old mice. Additionaly, it was analyzed the impact of aging in the active microbial communities of mouth, duodenum and colon at 2, 9, 15, 24 and 30 months of age (chapter 4). Changes were observed at every age and different taxonomical levels, with a greater shift at 15 months of age. This is related to the age of the mice, as at middle age systemic changes related to the aging process start to occur. At old ages, there was an increment of the pathobiontic species Helicobacter hepaticus and Helicobacter ganmani in the duodenum and colon. The oral, duodenal and colonic microbial communities are important pieces of information that can be related to the health status of the host. Research that focuses on assessing the changes in the different niches and not only in the feces, gives a broader overview of the microbial community of the host.