Institut für Nutztierwissenschaften

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Central carbon metabolism, sodium-motive electron ransfer, and ammonium formation by the vaginal pathogen Prevotella bivia
(2021) Schleicher, Lena; Herdan, Sebastian; Fritz, Günter; Trautmann, Andrej; Seifert, Jana; Steuber, Julia
Replacement of the Lactobacillus dominated vaginal microbiome by a mixed bacterial population including Prevotella bivia is associated with bacterial vaginosis (BV). To understand the impact of P. bivia on this microbiome, its growth requirements and mode of energy production were studied. Anoxic growth with glucose depended on CO2 and resulted in succinate formation, indicating phosphoenolpyruvate carboxylation and fumarate reduction as critical steps. The reductive branch of fermentation relied on two highly active, membrane-bound enzymes, namely the quinol:fumarate reductase (QFR) and Na+-translocating NADH:quinone oxidoreductase (NQR). Both enzymes were characterized by activity measurements, in-gel fluorography, and VIS difference spectroscopy, and the Na+-dependent build-up of a transmembrane voltage was demonstrated. NQR is a potential drug target for BV treatment since it is neither found in humans nor in Lactobacillus. In P. bivia, the highly active enzymes L-asparaginase and aspartate ammonia lyase catalyze the conversion of asparagine to the electron acceptor fumarate. However, the by-product ammonium is highly toxic. It has been proposed that P. bivia depends on ammonium-utilizing Gardnerella vaginalis, another typical pathogen associated with BV, and provides key nutrients to it. The product pattern of P. bivia growing on glucose in the presence of mixed amino acids substantiates this notion.
Electronic nose for the rapid detection of deoxynivalenol in wheat using classification and regression trees
(2022) Camardo Leggieri, Marco; Mazzoni, Marco; Bertuzzi, Terenzio; Moschini, Maurizio; Prandini, Aldo; Battilani, Paola
Mycotoxin represents a significant concern for the safety of food and feed products, and wheat represents one of the most susceptible crops. To manage this issue, fast, reliable, and low-cost test methods are needed for regulated mycotoxins. This study aimed to assess the potential use of the electronic nose for the early identification of wheat samples contaminated with deoxynivalenol (DON) above a fixed threshold. A total of 214 wheat samples were collected from commercial fields in northern Italy during the periods 2014–2015 and 2017–2018 and analyzed for DON contamination with a conventional method (GC-MS) and using a portable e-nose “AIR PEN 3” (Airsense Analytics GmbH, Schwerin, Germany), equipped with 10 metal oxide sensors for different categories of volatile substances. The Machine Learning approach “Classification and regression trees” (CART) was used to categorize samples according to four DON contamination thresholds (1750, 1250, 750, and 500 μg/kg). Overall, this process yielded an accuracy of >83% (correct prediction of DON levels in wheat samples). These findings suggest that the e-nose combined with CART can be an effective quick method to distinguish between compliant and DON-contaminated wheat lots. Further validation including more samples above the legal limits is desirable before concluding the validity of the method.
Feed clusters according to In Situ and In Vitro ruminal crude protein degradation
(2023) Okon, Paul; Bachmann, Martin; Wensch-Dorendorf, Monika; Titze, Natascha; Rodehutscord, Markus; Rupp, Christiane; Susenbeth, Andreas; Greef, Jörg Michael; Zeyner, Annette
Effective degradation (ED) of crude protein (CP) was estimated in vitro at 0.02, 0.05 and 0.08 h−1 assumed ruminal passage rates for a total of 40 feedstuffs, for which in situ ED was available and used as reference degradation values. For this, the Streptomyces griseus protease test was used. The differences between in vitro CP degradation and the in situ CP degradation values were lowest in legume grains and highest in cereal by-products and barley. The differences between in situ and in vitro ED were expressed using a degradation quotient (degQ), where degQ = (EDin vitro − EDin situ)/EDin situ. Among the tested feedstuffs, eight specific clusters were identified according to degQ for the assumed passage rates. The feedstuffs clustered in an unspecific way, i.e., feedstuffs of different nutrient composition, origin or treatment did not necessarily group together. Formaldehyde–treated rapeseed meal, soybean meal, wheat, a treated lupin, sunflower meal and barley could not be assigned to any of the clusters. Groupwise degradation (range of degQ for assumed passage rates are given in brackets) was detected in grass silages (−0.17, −0.11), cereal by-products together with sugar beet pulp (−0.47, −0.35) and partly in legume grains (−0.14, 0.14). The clustering probably based on different specific nutrient composition and matrix effects that influence the solubility of feed protein and limit the performance of the protease. The matrix can be affected by treatment (chemically, thermally or mechanically), changing the chemical and physical structure of the protein within the plant. The S. griseus protease test had reliable sensitivity to reflect differences between native feedstuffs and treatments (thermally or chemically) that were found in situ. The in situ results, however, are mostly underestimated. The clustering results do not allow a clear conclusion on the groupwise or feed-specific use of carbohydrate-degrading enzymes as pre- or co-inoculants as part of the S. griseus protease test and need to be tested for its potential to make this test more conform with in situ data.
Bi-objective optimization of nutrient intake and performance of broiler chickens using Gaussian process regression and genetic algorithm
(2023) Ahmadi, Hamed; Rodehutscord, Markus; Siegert, Wolfgang
This study investigated whether quantifying the trade-off between the maxima of two response traits increases the accuracy of diet formulation. To achieve this, average daily weight gain (ADG) and gain:feed ratio (G:F) responses of 7–21-day-old broiler chickens to the dietary supply of three nutrients (intake of digestible glycine equivalents, digestible threonine, and total choline) were modeled using a newly developed hybrid machine learning-based method of Gaussian process regression and genetic algorithm. The dataset comprised 90 data lines. Model-fit-criteria indicated a high model adjustment and no prediction bias of the models. The bi-objective optimization scenarios through Pareto front revealed the trade-off between maximized ADG and maximized G:F and provided information on the needed input of the three nutrients that interact with each other to achieve the trade-off scenarios. The trade-off scenarios followed a nonlinear pattern. This indicated that choosing target values intermediate to maximized ADG and G:F after single-objective optimization is less accurate than feed formulation after quantifying the trade-off. In conclusion, knowledge of the trade-off between maximized ADG and maximized G:F and the needed nutrient inputs will help feed formulators to optimize their feed with a more holistic approach.
Dietary phosphorus and calcium in feed affects miRNA profiles and their mRNA targets in jejunum of two strains of laying hens
(2021) Iqbal, Muhammad Arsalan; Ali, Asghar; Hadlich, Frieder; Oster, Michael; Reyer, Henry; Trakooljul, Nares; Sommerfeld, Vera; Rodehutscord, Markus; Wimmers, Klaus; Ponsuksili, Siriluck
Phosphorus (P) and calcium (Ca) are critical for egg production in laying hens. Most of P in plant-based poultry diet is bound as phytic acid and needs to be hydrolysed before absorption. To increase P bioavailability, exogenous phytases or bioavailable rock phosphate is added in feed. There is growing evidence of the importance of miRNAs as the epicentre of intestinal homeostasis and functional properties. Therefore, we demonstrated the expression of miRNA profiles and the corresponding target genes due to the different levels of P (recommended vs. 20% reduction) and/or Ca (recommended vs. 15% reduction) in feed. Jejunal miRNA profiles of Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) laying hens strains were used (n = 80). A total of 34 and 76 miRNAs were differentially expressed (DE) in the different diet groups within LSL and LB strains respectively. In LSL, the DE miRNAs and their targets were involved in calcium signaling pathway, inositol phosphate metabolism, and mitochondrial dysfunction. Similarly, in LB miRNAs targets were enriched in metabolic pathways such as glutathione metabolism, phosphonate metabolism and vitamin B6 metabolism. Our results suggest that both strains employ different intrinsic strategies to cope with modulated P and Ca supply and maintain mineral homeostasis.
The genome reduction excludes the ribosomal rescue system in acholeplasmataceae
(2022) Zübert, Christina; Ilic, Anna-Marie; Duduk, Bojan; Kube, Michael
The trans-translation process is a ribosomal rescue system for stalled ribosomes processing truncated mRNA. The genes ssrA and smpB fulfil the key functions in most bacteria, but some species have either lost these genes or the function of the ribosomal rescue system is taken over by other genes. To date, the ribosomal rescue system has not been analysed in detail for the Acholeplasmataceae. This family, in the Mollicutes class, comprises the genus Acholeplasma and the provisional taxon “Candidatus Phytoplasma”. Despite their monophyletic origin, the two clades can be separated by traits such as not representing primary pathogens for acholeplasmas versus being phytopathogenic for the majority of phytoplasmas. Both taxa share reduced genomes, but only phytoplasma genomes are characterised by a remarkable level of instability and reduction. Despite the general relevance of the ribosomal rescue system, information is lacking on coding, the genomic context and pseudogenisation of smpB and ssrA and their possible application as a phylogenetic marker. Herein, we provide a comprehensive analysis of the ribosomal rescue system in members of Acholeplasmataceae. The examined Acholeplasmataceae genomes encode a ribosomal rescue system, which depends on tmRNA encoded by ssrA acting in combination with its binding protein SmpB. Conserved gene synteny is evident for smpB, while ssrA shows a less conserved genomic context. Analysis of the tmRNA sequences highlights the variability of proteolysis tag sequences and short conserved sites at the 5′- and 3′-ends. Analyses of smpB provided no hints regarding the coding of pseudogenes, but they did suggest its application as a phylogenetic marker of Acholeplasmataceae – in accordance with 16S rDNA topology. Sequence variability of smpB provides sufficient information for species assignment and phylogenetic analysis.
Microbial incubations of 8‐phenyloctanoic acid and furan fatty acids in rumen fluid
(2022) Wiedmaier‐Czerny, Nina; Blumberg, Olga; Schulz, Tobias; Kemmler, Franziska; Titze, Natascha; Wild, Katharina; Vetter, Walter
Aims: The digestive tract of ruminants is specialized in the digestion of various plant components. One of the largest parts of the stomach is the so-called rumen, which contains a large number of micro-organisms that may degrade or modify fatty acids, for example by β-oxidation, chain elongation and/or hydrogenation. Methods and Results: Here we performed incubation experiments with less com- mon fatty acids by in vitro incubations with rumen fluid of fistulated cows for 24 h. Sample extracts were analysed by gas chromatography with mass spectrometry. As substrates, we selected one phenyl fatty acid and four furan fatty acids (FuFAs). All studied fatty acids were degraded by β-oxidation (two or three chain-shortening steps) while chain elongation or saturation of the aromatic part (terminal phenyl or central furan moiety) was not observed in any case. Conclusions: The percentage of β-oxidation products was low, especially in the case of the FuFAs. This could be due to the rather long carbon number of FuFAs (19–22 carbon atoms). In addition, compound-specific differences in the degradation rates were observed in our experiments. Significance and Impact of the Study: Our results produce evidence that FuFAs, which are valuable antioxidants that are known to be present in various feed items of the cow, can be effectively passed on the rumen into the milk.
Dynamic development of viral and bacterial diversity during grass silage preservation
(2023) Sáenz, Johan S.; Rios-Galicia, Bibiana; Rehkugler, Bianca; Seifert, Jana
Ensilaging is one of the most common feed preservation processes using lactic acid bacteria to stabilize feed and save feed quality. The silage bacterial community is well known but the role of the virome and its relationship with the bacterial community is scarce. In the present study, metagenomics and amplicon sequencing were used to describe the composition of the bacterial and viral community during a 40-day grass silage preservation. During the first two days, we observed a rapid decrease in the pH and a shift in the bacterial and viral composition. The diversity of the dominant virus operational taxonomic units (vOTUs) decreased throughout the preservation. The changes in the bacterial community resembled the predicted putative host of the recovered vOTUs during each sampling time. Only 10% of the total recovered vOTUs clustered with a reference genome. Different antiviral defense mechanisms were found across the recovered metagenome-assembled genomes (MAGs); however, only a history of bacteriophage infection with Lentilactobacillus and Levilactobacillus was observed. In addition, vOTUs harbored potential auxiliary metabolic genes related to carbohydrate metabolism, organic nitrogen, stress tolerance, and transport. Our data suggest that vOTUs are enriched during grass silage preservation, and they could have a role in the establishment of the bacterial community.
Male reproductive organ weight: Criteria for detection of androstenone-positive carcasses in immunocastrated and entire male pigs
(2023) Fazarinc, Gregor; Batorek-Lukač, Nina; Škrlep, Martin; Poklukar, Klavdija; Van den Broeke, Alice; Kress, Kevin; Labussière, Etienne; Stefanski, Volker; Vrecl, Milka; Čandek-Potokar, Marjeta
Immunocastration and rearing of entire males (EMs) are sustainable alternatives to surgical castration. However, these animal carcasses have variable risk of boar taint and should be identified at the slaughter line. We aimed to identify a simple and reliable indicator of androstenone-related boar taint by evaluating pelvic urogenital tract weight as a marker of boar-taint animals at the slaughter line. The pelvic urogenital tract, testes, and accessory sex glands of EMs and immunocastrates (ICs) were collected, dissected, and weighed, before colorimetric measurements of testicular tissue. Additionally, GnRH antibody titers and testosterone, androstenone, and skatole levels were determined. Our results showed that 81.8% of EMs had androstenone levels above the risk threshold (>0.5 µg/g fat; EM/Ahigh subgroup), whereas in ICs, the C/Ahigh subgroup with androstenone >0.5 µg/g fat accounted for only 4.3%. Androstenone levels correlated negatively with GnRH antibody titers and positively with testosterone levels and reproductive organ weights. Identification of ICs with androstenone levels above the threshold (IC/Ahigh subgroup) may be achieved via testes or pelvic urogenital tract weight measurements. However, in EMs, the latter is a more reliable parameter. A principal component analysis based on these variables and hierarchical clustering also distinguished the Ahigh from the Alow subgroup, irrespective of IC/EM. The findings highlight the possible use of pelvic urogenital tract weight along with testes weight as a simple, reliable, and efficient morphometric indicator for identifying androstenone-positive carcasses of different sex categories.
Genome comparison of ‘Candidatus Phytoplasma rubi’ with genomes of other 16SrV phytoplasmas highlights special group features
(2023) Böhm, Jan Werner; Duckeck, Dominik; Duduk, Bojan; Schneider, Bernd; Kube, Michael
Phytoplasmas are associated with important bacterial diseases, causing severe symptoms in agricultural and ornamental crops. ‘Candidatus Phytoplasma rubi’, associated with the Rubus stunt in raspberries (Rubus idaeus) and blackberries (Rubus subgenus Rubus), causes shortened internodes, elongated sepals, proliferation, phyllody, and virescence. The recently published genome of ‘Ca. P. rubi’ RS enabled a comprehensive genomic comparison to the complete genomes of 16SrV phytoplasmas, comprising strains of the flavescence dorée-associated phytoplasma CH and two ‘Candidatus Phytoplasma ziziphi’ strains. Besides the typical transporters and metabolic features of phytoplasmas, the phosphorolysis of sucrose and the utilization of the carboxylic acid L-lactate became apparent for the 16SrV-group. With respect to the effector repertoire and the encoded immunodominant membrane proteins involved in host colonization, the group revealed conserved features that comprise the variable membrane proteins A and B. However, SAP11- and SAP54 orthologs were limited to ‘Ca. P. rubi’ RS and ‘Ca. P. ziziphi’. Genome-sequence-based phylogenetic analysis supports the close relationship of these genomes relative to alder yellows phytoplasmas. The analyses supported the impact of the mobilome on phytoplasma evolution but also highlighted that there is the possibility of identifying phytoplasmas with a larger metabolic repertoire in the future.
Reduced parasite burden in feral honeybee colonies
(2023) Kohl, Patrick L.; D'Alvise, Paul; Rutschmann, Benjamin; Roth, Sebastian; Remter, Felix; Steffan‐Dewenter, Ingolf; Hasselmann, Martin
Bee parasites are the main threat to apiculture and since many parasite taxa can spill over from honeybees (Apis mellifera) to other bee species, honeybee disease management is important for pollinator conservation in general. It is unknown whether honeybees that escaped from apiaries (i.e. feral colonies) benefit from natural parasite‐reducing mechanisms like swarming or suffer from high parasite pressure due to the lack of medical treatment. In the latter case, they could function as parasite reservoirs and pose a risk to the health of managed honeybees (spillback) and wild bees (spillover). We compared the occurrence of 18 microparasites among managed (N = 74) and feral (N = 64) honeybee colony samples from four regions in Germany using qPCR. We distinguished five colony types representing differences in colony age and management histories, two variables potentially modulating parasite prevalence. Besides strong regional variation in parasite communities, parasite burden was consistently lower in feral than in managed colonies. The overall number of detected parasite taxa per colony was 15% lower and Trypanosomatidae, chronic bee paralysis virus, and deformed wing viruses A and B were less prevalent and abundant in feral colonies than in managed colonies. Parasite burden was lowest in newly founded feral colonies, intermediate in overwintered feral colonies and managed nucleus colonies, and highest in overwintered managed colonies and hived swarms. Our study confirms the hypothesis that the natural mode of colony reproduction and dispersal by swarming temporally reduces parasite pressure in honeybees. We conclude that feral colonies are unlikely to contribute significantly to the spread of bee diseases. There is no conflict between the conservation of wild‐living honeybees and the management of diseases in apiculture.
Optimization strategies to adapt sheep breeding programs to pasture-based production environments: A simulation study
(2023) Martin, Rebecca; Pook, Torsten; Bennewitz, Jörn; Schmid, Markus
Strong differences between the selection (indoor fattening) and production environment (pasture fattening) are expected to reduce genetic gain due to possible genotype-by-environment interactions (G × E). To investigate how to adapt a sheep breeding program to a pasture-based production environment, different scenarios were simulated for the German Merino sheep population using the R package Modular Breeding Program Simulator (MoBPS). All relevant selection steps and a multivariate pedigree-based BLUP breeding value estimation were included. The reference scenario included progeny testing at stations to evaluate the fattening performance and carcass traits. It was compared to alternative scenarios varying in the progeny testing scheme for fattening traits (station and/or field). The total merit index (TMI) set pasture-based lamb fattening as a breeding goal, i.e., field fattening traits were weighted. Regarding the TMI, the scenario with progeny testing both in the field and on station led to a significant increase in genetic gain compared with the reference scenario. Regarding fattening traits, genetic gain was significantly increased in the alternative scenarios in which field progeny testing was performed. In the presence of G × E, the study showed that the selection environment should match the production environment (pasture) to avoid losses in genetic gain. As most breeding goals also contain traits not recordable in field testing, the combination of both field and station testing is required to maximize genetic gain.
Detailed genomic analysis of correlation and causality between milk production and health traits in German Holstein cattle using high-dimensional genomic data and novel statistical methods
(2024) Schneider, Helen Hiam; Bennewitz, Jörn
Adverse side effects of high milk production on animal health have been mentioned frequently. They are compromising animal welfare, the farmers` economy, and the ecological footprint as well as the social acceptance of milk production. Consequently, many countries started to include functional traits into their breeding goal a few decades ago. The intention is thereby to avoid putative undesirable side effects of high production and to improve the cows` health in the long term through genetic gain. Indeed, positive genetic trends for various functional and health traits have been described in the literature. At the same time, the genetic trend of milk production traits remained positive. In general, sustainable genetic gain requires an appropriate weight of the individual traits in the selection index and a comprehensive understanding of the traits` genetic architecture and their interrelationship. This can be facilitated by recent innovations that enable the widespread availability of whole genome sequence (WGS) data. WGS data contains genomic information about millions of SNPs, derived either from sequencing or from imputing lower density SNP chip data to sequence level. Using external information about these sequence variants in genomic analyses, e.g., concerning their function during transcription and translation, has been shown to reveal additional knowledge about biological and molecular mechanisms shaping complex traits. Hence, applying external information to estimate genetic correlations might help to dissect the traits` interrelationship in more detail. Additionally, going beyond global genetic correlations, this is, reflecting the shared genetic effect throughout the genome, to the local scale, this is, the genetic sharing in specific genomic regions, would be an alternative to provide novel knowledge about the extent and direction of the shared genetic effect and its localization in the genome. The expected information is desired to understand and to avoid potential detrimental effects of selection decisions on animal health. Moreover, moving away from correlation towards causation would enable to predict the impact of management decisions and external interventions. The aim of this thesis was to scrutinize the genetic connection between health and milk production traits in dairy cattle using a large sample of 34,497 German Holstein cows with pedigree, 50K SNP chip, and imputed WGS data consisting of ~17 million variants. To this end, standard quantitative genetic analyses were augmented by a set of novel approaches to detect genomic regions with a substantial genetic effect on several traits and to investigate causal associations. Chapter one applied the 50K chip data to estimate additive genetic and dominance variance components for the milk production and health traits. This was done since substantial nonadditive genetic effects for functional traits have been mentioned in the literature, whereas little is known about these effects for the health traits examined in this thesis. It was demonstrated that the contribution of the dominance variance to the phenotypic variance was rather small for all traits. However, regarding the health traits, the contribution of the dominance variance to the genetic variance was almost as high as, and sometimes even higher than the contribution of the additive genetic variance. In addition, significant inbreeding depression was found for the milk production traits. Chapter two consisted of three steps. First, pedigree-based heritabilities of and global genetic correlations between milk production and health traits were estimated. Most heritabilities of the health traits and their genetic correlations with the milk production traits were low, whereby the genetic correlations were in an unfavorable direction. Next, genome-wide association studies (GWAS) were performed for each trait utilizing the 50K chip data to generate summary statistics. The summary statistics are required as input data for the last step that applied a tool to detect shared genomic regions. Genomic regions simultaneously affecting milk production and health traits were identified for each trait combination, of which some also had a sign in the favorable direction. This chapter confirmed the advantage of scrutinizing global genetic correlations down to the local scale. Chapter three utilized the 50K chip as well as the imputed WGS data. The latter was thereby divided into 27 subsets depending on the variants` functional and evolutionary annotation, e.g., as gene expression quantitative trait loci or selection signature. Heritabilities of and genetic correlations between milk yield and several health traits were estimated for the 50K chip and each of the 27 subsets. The results indicate that the 50K chip appears to be sufficient to explain the genetic variance of the investigated traits, whereas it seems to underestimate their genetic covariance. Furthermore, the importance of alternative splicing for the (co-)variation of quantitative traits and the important role of the negative energy balance causing the unfavorable side effects of high production on animal health has been confirmed. Chapter four was a Mendelian randomization (MR) analysis. Here, the causal effect of milk yield on a set of health traits was examined using a method that is based on summary statistics. In this chapter, the summary statistics were generated using the imputed WGS data. Unfavorable causal effects of milk yield on most health traits were identified that were strongest for mastitis and digital phlegmon. This indicates potential detrimental consequences for these traits with increasing milk yields, owed to selection decisions or inappropriately chosen weights in the selection index. The general discussion is addressing the negative side effects of high production on animal health with special focus on the negative energy balance. Moreover, including feed efficiency and resilience indicator traits into the breeding goal is discussed with respect to the results reported in the previous chapters. Besides, additional information about the methodology of MR analyses and the results of a MR analysis investigating the causal effect of protein and fat yield on the health traits are presented and debated. The general discussion ends with practical implications of the results regarding hologenomic selection strategies and strategies including functional information in genomic prediction.
Dietary L-carnitine supplementation modifies blood parameters of mid-lactating dairy cows during standardized lipopolysaccharide-induced inflammation
(2024) Seemann, Leonie; Frahm, Jana; Kersten, Susanne; Bühler, Susanne; Meyer, Ulrich; Visscher, Christian; Huber, Korinna; Dänicke, Sven
L-carnitine, available as feed additive, is essential for the beta-oxidation of free fatty acids in the mitochondrial matrix. It provides energy to immune cells and may positively impact the functionality of leukocytes during the acute phase response, a situation of high energy demand. To test this hypothesis, German Holstein cows were assigned to a control group (CON, n = 26) and an L-carnitine supplemented group (CAR, n = 27, rumen-protected L-carnitine product: 125 g/cow/d, corresponded to total L-carnitine intake: 25 g/cow/d, supplied with concentrate) and received an intravenous bolus injection of lipopolysaccharides (LPS, 0.5 µg/kg body weight, E. coli) on day 111 postpartum as a model of standardized systemic inflammation. Blood samples were collected from day 1 ante injectionem until day 14 post injectionem (pi), with frequent sampling through an indwelling venous catheter from 0.5 h pi to 12 h pi. All parameters of the white blood cell count responded significantly to LPS, while only a few parameters were affected by L-carnitine supplementation. The mean eosinophil count, as well as the percentage of basophils were significantly higher in CAR than in CON over time, which may be due to an increased membrane stability. However, phagocytosis and production of reactive oxygen species by leukocytes remained unchanged following L-carnitine supplementation. In conclusion, although supplementation with 25 g L-carnitine per cow and day resulted in increased proportions of specific leukocyte populations, it had only minor effects on the functional parameters studied in mid-lactating dairy cows during LPS-induced inflammation, and there was no evidence of direct improvement of immune functionality.
A shift towards succinate‐producing Prevotella in the ruminal microbiome challenged with monensin
(2022) Trautmann, Andrej; Schleicher, Lena; Koch, Ariane; Günther, Johannes; Steuber, Julia; Seifert, Jana
The time‐resolved impact of monensin on the active rumen microbiome was studied in a rumen‐simulating technique (Rusitec) with metaproteomic and metabolomic approaches. Monensin treatment caused a decreased fibre degradation potential that was observed by the reduced abundance of proteins assigned to fibrolytic bacteria and glycoside hydrolases, sugar transporters and carbohydrate metabolism. Decreased proteolytic activities resulted in reduced amounts of ammonium as well as branched‐chain fatty acids. The family Prevotellaceae exhibited increased resilience in the presence of monensin, with a switch of the metabolism from acetate to succinate production. Prevotella species harbour a membrane‐bound electron transfer complex, which drives the reduction of fumarate to succinate, which is the substrate for propionate production in the rumen habitat. Besides the increased succinate production, a concomitant depletion of methane concentration was observed upon monensin exposure. Our study demonstrates that Prevotella sp. shifts its metabolism successfully in response to monensin exposure and Prevotellaceae represents the key bacterial family stabilizing the rumen microbiota during exposure to monensin.
Squid meal and shrimp hydrolysate as novel protein sources for dog food
(2024) Guilherme-Fernandes, Joana; Aires, Tiago; Fonseca, António J. M.; Yergaliyev, Timur; Camarinha-Silva, Amélia; Lima, Sofia A. C.; Maia, Margarida R. G.; Cabrita, Ana R. J.
The world’s growing pet population is raising sustainability and environmental concerns for the petfood industry. Protein-rich marine by-products might contribute to mitigating negative environmental effects, decreasing waste, and improving economic efficiency. The present study evaluated two marine by-products, squid meal and shrimp hydrolysate, as novel protein sources for dog feeding. Along with the analysis of chemical composition and antioxidant activity, palatability was evaluated by comparing a commercial diet (basal diet) and diets with the inclusion of 150 g kg−1 of squid meal or shrimp hydrolysate using 12 Beagle dogs (2.2 ± 0.03 years). Two in vivo digestibility trials were conducted with six dogs, three experimental periods (10 days each) and three dietary inclusion levels (50, 100 and 150 g kg−1) of squid meal or shrimp hydrolysate in place of the basal diet to evaluate effects of inclusion level on apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites, and microbiota. Both protein sources presented higher protein and methionine contents than ingredients traditionally used in dog food formulation. Shrimp hydrolysate showed higher antioxidant activity than squid meal. First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet. Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources. The higher ATTD of dry matter, most nutrients and energy of diets with the inclusion of both by-products when compared to the basal diet, suggests their potential to be included in highly digestible diets for dogs. Although not affected by the inclusion level of protein sources, when compared to the basal diet, the inclusion of squid meal decreased butyrate concentration and shrimp hydrolysate increased all volatile fatty acids, except butyrate. Fecal microbiota was not affected by squid meal inclusion, whereas inclusion levels of shrimp hydrolysate significantly affected abundances of Oscillosperaceae (UCG-005), Firmicutes and Lactobacillus. Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value.
High rates of honey bee colony losses and regional variability in Ethiopia based on the standardised COLOSS 2023 survey
(2024) Hailu, Teweldemedhn Gebretinsae; Atsbeha, Alem Tadesse; Wakjira, Kibebew; Gray, Alison
The COLOSS research association has been assessing honey bee colony losses, associated risk factors and management, focusing on Western countries but with a progressive international expansion. Here, we report the first survey on the loss rates of colonies in 2022/2023 in Ethiopia using COLOSS monitoring survey tools. A face-to-face interview questionnaire survey was conducted on 64 beekeepers selected from Oromia and Tigray regions. This covered 1713 honey bee colonies distributed in 68 apiaries. The percentages of colonies lost were significantly different between Oromia (24.1%) and Tigray (66.4%) regions. Colony losses were attributed as unsolvable queen problems (8% in Oromia; 10% in Tigray), natural disaster (32%; 82%), and empty hives or dead colonies (60%; 8%). The loss rate was significantly affected by queen replacement (p < 0.0001), use of natural comb (p < 0.0001), feed supplementation (p < 0.0001), region (p < 0.0001), varroa treatment (p < 0.0001), colony splitting (p < 0.01), and merging (p < 0.01). Beekeepers in Oromia managed more colonies and implemented improved practices compared to those in Tigray. However, all beekeepers in Oromia detected at least some bees with signs of deformed wing virus, compared to 76% of beekeepers in Tigray. In conclusion, the colony loss rate was significantly different between Oromia and Tigray regions due to differences in natural disasters, management, environment and health factors.
Influence of different plant extracts on CYP-mediated skatole and indole degradation in pigs
(2024) Marro, Philipp; Wesoly, Raffael; Stefanski, Volker
One of the primary substances responsible for the unpleasant odor in boar meat is skatole. Enzymes belonging to the cytochrome P450 (CYP) family play a pivotal role in the hepatic clearance of skatole. This study aimed to investigate the impact of oregano essential oil (OEO), Schisandra chinensis extract (SC), and garlic essential oil (GEO) on hepatic CYP2E1 and CYP2A activity in pigs. In three consecutive trials, cannulated castrated male pigs were provided with a diet containing 0.2–0.3% of one of these plant extracts. Following a 14-day feeding period, the animals were slaughtered, and liver and fat samples were collected. The findings indicate that the activities of CYP2E1 were unaffected by any treatment. However, GEO treatment demonstrated a significant reduction in CYP2A activity (p < 0.05). Pigs treated with GEO also exhibited a notable increase in skatole concentrations in both plasma and adipose tissue. In contrast, animals fed SC displayed elevated skatole concentrations in plasma but not in fat tissue. OEO did not influence skatole concentrations in either blood or fat. Furthermore, the study revealed that a supplementation of 6 g GEO per animal per day induced a significant increase in skatole concentrations in blood plasma within 24 h.
Divergence within the taxon ‘Candidatus Phytoplasma asteris’ confirmed by comparative genome analysis of carrot strains
(2024) Toth, Rafael; Ilic, Anna-Marie; Huettel, Bruno; Duduk, Bojan; Kube, Michael
Phytoplasmas are linked to diseases in hundreds of economically important crops, including carrots. In carrots, phytoplasmosis is associated with leaf chlorosis and necrosis, coupled with inhibited root system development, ultimately leading to significant economic losses. During a field study conducted in Baden-Württemberg (Germany), two strains of the provisional taxon ‘Candidatus Phytoplasma asteris’ were identified within a carrot plot. For further analysis, strains M8 and M33 underwent shotgun sequencing, utilising single-molecule-real-time (SMRT) long-read sequencing and sequencing-by-synthesis (SBS) paired-end short-read sequencing techniques. Hybrid assemblies resulted in complete de novo assemblies of two genomes harboring circular chromosomes and two plasmids. Analyses, including average nucleotide identity and sequence comparisons of established marker genes, confirmed the phylogenetic divergence of ‘Ca. P. asteris’ and a different assignment of strains to the 16S rRNA subgroup I-A for M33 and I-B for M8. These groups exhibited unique features, encompassing virulence factors and genes, associated with the mobilome. In contrast, pan-genome analysis revealed a highly conserved gene set related to metabolism across these strains. This analysis of the Aster Yellows (AY) group reaffirms the perception of phytoplasmas as bacteria that have undergone extensive genome reduction during their co-evolution with the host and an increase of genome size by mobilome.
Mothers’ parity and weaning age influence the transition from liquid to solid feed in female Holstein calves
(2023) Schwarzkopf, Sarah; Huber, Korinna
Milchbauern streben aus wirtschaftlichen Gründen ein junges Erstkalbealter an. Da diese jungen Färsen während der Trächtigkeit noch wachsen, könnten sie mit ihrem Kalb um Nährstoffe konkurrieren. Daher können die Parität der Mütter und die damit verbundene Nährstoffversorgung während der Trächtigkeit die frühe Entwicklung beeinflussen. Kälber werden als funktionell monogastrische Tiere geboren, die auf Milch oder Milchaustauscher zur Ernährung angewiesen sind. Um den Status eines Wiederkäuers zu erreichen und festes Futter als Nahrungsquelle zu verwenden, müssen sich viele digestive, endokrine und biochemische Funktionen ändern. Daher ist das Absetzen ein kritisches und potenziell stressiges Ereignis. Das durchschnittliche Absetzalter weiblicher Milchkälber beträgt 6 – 11 Wochen, was mit Stress einhergeht, der das Immunsystem, das Wachstum und die Magen-Darm-Entwicklung negativ beeinträchtigen kann. Daher kommt ein Aufschieben des Absetzens möglicherweise der Gesundheit und Entwicklung der Kälber zugute. Es verbessert das Wachstum, reduziert die mit dem Absetzen verbundene Belastung und erhöht möglicherweise das Alter bei der Entfernung aus der Herde. Die vorliegende Arbeit zielte darauf ab, die Auswirkungen von zwei Absetzaltersstufen und der Parität der Mütter auf die Entwicklung und Anpassung an die Entwöhnung zu identifizieren. Mittels eines Tierversuchs mit neunundfünfzig weiblichen Holstein-Kälbern wurden die Auswirkungen eines frühen (7 Wochen) und späten (17 Wochen) Absetzens auf Wachstum, Verhalten, Pansen- und Magen-Darm-Entwicklung und Anpassung des Leber- und Nierenstoffwechsels getestet. Darüber hinaus wurde der Einfluss unterschiedlicher Absetzalter auf Kälber von primiparen und multiparen Kühen berücksichtigt. Proben wurden kontinuierlich im Alter von 8 Tagen (Versuchstag 1) bis zum Alter von 21 Wochen (Versuchstag 140) genommen. Die Analysen und Ergebnisse werden in drei begutachteten wissenschaftlichen Arbeiten beschrieben und im Folgenden zusammengefasst. Die Wachstumsleistung wurde anhand von Lebendgewicht, Lebendgewichtszunahme, Widerrist- und Hüfthöhe, Brustumfang, Rücken- und Körperlänge bewertet. Der Energiestoffwechsel und die Leberfunktion wurden durch Messung der Serumkonzentrationen von Glukose, Insulin, Harnstoff, Cholesterin, Leptin, Beta-hydroxybutyrate und nicht-veresterten Fettsäuren quantifiziert (Manuskript 1). Das Verhalten der Tiere wurde beobachtet unterteilt in Ruhe-, Kau- und Aktivverhalten, um Rückschlüsse auf Anzeichen von Hunger und Stress sowie der Pansenentwicklung zu ziehen. Die Pansenentwicklung und entsprechende metabolische und adaptive Veränderungen im Säure-Basen-Stoffwechsel wurden durch Messung des pH-Wertes in Urin, Kot und Speichel sowie stickstoffhaltiger Metaboliten im Urin bewertet (Manuskript 2). Das Mikrobiom in Kotproben wurde analysiert, um die Reifung des Magen-Darm-Trakts zu beurteilen. Um Einblicke in metabolische Anpassungen zu erhalten, wurde eine umfassende Anzahl an Metaboliten gemessen. Dazu gehörten Aminosäuren, biogene Amine, Acylcarnitine und Sphingomyeline (Manuskript 3). Ein späteres Absetzen im Alter von 17 Lebenswochen wirkt sich positiv auf das Körperwachstum und die Anpassung des Energie- und Säure-Basen-Stoffwechsels aus (Manuskript 1; Manuskript 2). Der pH-Wert des Speichels stieg während des Experiments im Laufe der Zeit an, unabhängig vom Absetzalter oder der Parität der Mutter (Manuskript 2). Da ein alkalischer pH-Wert im Speichel für dessen Pufferkapazität wichtig ist, unterstreicht dies, wie wichtig es ist, das Absetzen zu verzögern. Die gastrointestinale Entwicklung war durch eine längere Milchaustauscheraufnahme nicht beeinträchtigt, sondern erreichte am Ende der Studie einen funktionellen Status. Faktoren der Pansenentwicklung (Manuskript 2) und die Mikrobiota im Kot (Manuskript 3) passten sich schnell an und deuteten auf eine altersabhängige Reifung hin. Die analysierten Metaboliten wiesen auf ausgeprägte Effekte eines frühen Absetzens auf verschiedene Stoffwechselwege hin (Manuskript 3). Insbesondere die Gluconeogenese in der Leber schienen bei früh abgesetzen Kälbern unzureichend zu sein. Die Leptinkonzentrationen und die Rückenlänge waren bei früh abgesetzten Kälbern primiparer Mütter reduziert, nicht jedoch bei spät abgesetzten Kälbern primiparer Mütter (Manuskript 1). Daher profitieren Kälber von primiparen Kühen besonders von einem späteren Absetzen. Die Ergebnisse zeigten, dass ein Absetzen im Alter von 7 Wochen nicht empfohlen werden kann, da es zu abrupten und möglicherweise belastenden Stoffwechselveränderungen und einer gestörten Reifung verschiedener Organe und deren Stoffwechselfunktionen führte. Die aktuelle Studie zeigte, dass die Verzögerung des Absetzens auf ein Alter von 17 Wochen einen gleichmäßigen Übergang verschiedener physiologischer Funktionen in den Wiederkäuerstatus ermöglicht. Deshalb schien es die mit dem Absetzen verbundenen Stoffwechselprobleme und den Stress zu reduzieren. Weitere Forschung über das Absetzen, unter Berücksichtigung der Aufzuchtkosten und späteren Milchleistung und Gesundheit, ist erforderlich.

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