Relationship between pubertal testicular ultrasonographic evaluation and future reproductive performance potential in Piétrain boars.

New ways of predicting sperm quality and output performance in young artificial insemination (AI) boars are important for breeding companies to ensure that the pubertal boars delivered to the AI studs have a high chance of meeting minimum quality standards to be used for insemination and therewith dissemination of desirable characteristics. The aim of the current study was to characterize the testicular development of 218 pubertal Piétrain boars (Line 408, Pig Improvement Company) to identify traits with predictable characteristics relative to their sperm quality as an adult AI boar. Scrotum, testes and epididymis were examined ultrasonographically at day (d) 100 (on-test) and 170 (off-test) followed by a computer-assisted grayscale analysis (GSA). Over the test period, paired testicular volume increased 7.3-fold from 22.7 ± 10.8 cm3 to 166.6 ± 62.2 cm3. The right testis was significantly (P = 0.014) larger than the left one at the off-test. Based on the sperm quality (ejaculate volume, sperm concentration, total sperm number, morphologically abnormal sperm and total sperm motility at day 3 of semen storage), 82.11% (n = 179) of the boars were classified as "productive" boars. These boars had a significantly (P = 0.039) larger paired testicular volume than "non-productive" boars (45.9 ± 19.9 cm3vs. 38.5 ± 12.6 cm3) at the on-test. For the right testis at on-test, significant differences for the standard deviation of mean gray value (P = 0.022), area under the curve (P = 0.004) and mean gradient value (GRAD, P = 0.030) regarding the future sperm production capacity (SPC) were shown. At off-test, there was a significant difference for minimum gray value (MIN GV, P = 0.003) and mean gray value (P = 0.001) related to SPC. To find SPC related cut-off values for GSA data, a two segmental non-linear regression analysis was carried out indicating breakpoints for GRAD ≥12 and MIN GV ≥ 40 for boars with low SPC. Off-test boars with MIN GV ≥ 40 showed a 2.4 higher risk to display low SPC (Odds ratio = 2.4 [1.1, 5.4]; P = 0.024). The results may enable breeding companies to include new sperm quality associated traits in their boar testing and selection programs.

Impact of hygiene on bacterial contamination in extended boar semen: An eight-year retrospective study of 28 European AI centers.

Antibiotic agents such as gentamicin represent essential components of semen extenders in order to reduce bacterial contamination. But antibiotic resistance increases and AI centers start utilizing antibiotic agents which are more potent. Therefore, a shift to preventing bacterial contamination has to take place. In this study, we could demonstrate that hygiene is a tool capable of reducing bacterial load. In order to analyze 1434 extended semen samples and nine specially established hygienic critical control points (HCCPs, n = 828), 92 quality control audits have been carried out in a time period from 2012 until 2019 in 28 European AI centers. The results show the process of introducing a basic hygienic standard in audit 1 (2012/2013) and 2 (2014/2015) and the resulting achievements by means of improved hygienic conditions in audit 3 (2016/2017) and 4 (2018/2019). Within the scope of audit 1, 19% of the semen samples were contaminated with bacteria (cutoff ≥100 colony-forming units/mL). Audit 2 showed a bacterial load of 13.6% whereas during audit 3 and 4 very low bacterial contamination rates were recorded (4.5 and 5.5%, respectively). In the same manner, analysis of hygiene at different CCPs during semen production showed a decrease in all average HCCP-scores (score 1-6) comparing audit 4 to 1. By regression analysis we could show a significant audit-dependent association of the bacterial contamination in semen samples and hygiene of HCCPs. Furthermore, analysis of the odds ratio (OR) reveals that the bacterial contamination of certain HCCPs poses an increased risk of receiving bacterially contaminated semen samples (filling machine: OR = 3.02, P = 0.06; extender: OR = 8.97, P < 0.001; inner face of dilution tank lids: OR = 3.14, P = 0.09). Around 60% of the variance of the bacterial contamination in semen samples could be explained by hygienic conditions at different control points and their interaction with audit period and AI center. Antimicrobial agents are essential to protect human and animal health but excessive or inappropriate use can lead to the emergence of resistant bacteria. As shown in our study, hygiene management can significantly reduce bacterial contamination and is therefore capable of preventing antibiotic resistance.

Development of predictive models for boar semen quality.

In this study a prognosis model is developed that predicts sperm quality characteristics based on external factors such as barn climate conditions, seasonality, semen collection frequency, age and breed of artificial insemination (AI) boars. For this a k-fold cross validation framework is used to test the prediction accuracy of a wide range of regression models that are based on different functional forms (linear, log-linear) and estimation techniques (ordinary least squares, seemingly unrelated regression, two-stage least squares estimation and three-stage least squares estimation). The dataset includes 241 boars from three barns within one boar stud located in Southern Germany, consisting of 7455 ejaculates collected during one year. The winner model predicts sperm motility with little error (Mean Absolute Percentage Error (MAPE): 4.35%), but is of limited use to predict sperm output (MAPE: 23.92%) and especially morphologically abnormal spermatozoa (MAPE: 44.67%). An estimation of marginal effects shows, that once confounding variables are controlled for, the considered barn climate variables do not have a measurable effect on sperm quality. Other factors have a more significant effect on sperm quality, like morphology-motility linkages, sperm concentration, interval between semen collections and to a lesser extent age and breed of the AI boar.

Effect of vibration emissions during shipping of artificial insemination doses on boar semen quality.

The shipping of semen doses to sow farms can impair boar semen quality. Unfortunately, there is currently no practice-oriented information available regarding general shipping conditions of boar semen. For this reason, a special mobile sensing app (TransportLog 1.0), utilizing the built-in sensors of smartphones, has been programmed to capture vibration emissions during shipping of semen doses (QuickTip Flexitubes®, Minitüb). Data were analyzed, transformed and used as standards for simulating vibration emissions from an orbital shaker IKA MTS 4 (Laborgeräte München) in a spermatological reference laboratory. Twenty ejaculates were collected randomly and diluted using a one-step isothermal process in a split-sample procedure in Beltsville Thawing Solution (BTS, Minitüb). The sperm concentration was adjusted to 24 × 106 sperm/mL. The dose filling volume was 85 ±â€¯1 mL. Samples were stored for seven days at 17 °C. The results showed that circular horizontal vibration emissions with frequencies of 300 rpm for a duration of 6 h led to a significant alkalization of the BTS-extended semen. Semen motility, mitochondrial activity, acrosome and plasma membrane integrity as well as thermo-resistance all demonstrated a frequency-dependent negative response to vibration emissions during long-term storage. This study leads to new insights and recommendations for the shipping of boar semen in the artificial insemination industry. Furthermore, a new monitoring tool for boar semen shipping was established using mobile sensing.

Validating genome-wide associated signals for clinical mastitis in German Holstein cattle.

A validation study for six genomic regions previously identified by a genome-wide association study for somatic cell score was conducted with data of clinical mastitis in German Holstein cattle. Out of 10 tested SNPs, five on chromosomes 6, 13 and 19 were significantly associated with clinical mastitis (P < 0.05). Three SNPs on chromosomes 6 and 19 had the same direction of effect as those previously reported in the initial genome-wide association study for somatic cell score. The other two SNPs on chromosome 13 had opposite effects. As well as validating associations within known QTL from previous studies, e.g. chromosomes 6 and 19, novel loci on chromosome 13 were confirmed. Promising candidate genes are, for example: deoxycytidine kinase, immunoglobulin J chain, vitamin D binding protein, forkhead box K2, sodium/hydrogen exchanger 8 and cytoplasmic nuclear factor of activated T-cells 2. Our confirmation study provides additional evidence for the functional role of the linked genomic regions to immune response. This information can be used as a basis for further functional studies for those potential genes.

Milk protein polymorphisms and casein haplotypes in Butana cattle.

Butana is a Bos indicus dairy cattle breed that is well adapted to the local environment of Sudan. The breed has been gradually declining in number due to breed substitution. Therefore, conservation and improvement strategies are required to maintain this breed. The aim of the present study was to assess genetic variation that is characteristic for Butana cattle in the milk protein genes CSN1S1, CSN2, CSN1S2, CSN3, LALBA, and LGB. In a first step, genomic DNA of five unrelated individuals was comparatively sequenced across all exon and flanking sequences. Ninety-three single nucleotide polymorphisms (SNPs) were identified in Butana cattle compared with the Bos taurus reference sequence at Ensembl. We confirmed the recently identified protein variants CSN2*J, CSN2*L, and LALBA*E. Fifty-two SNPs in non-coding regions are novel. Among the novel SNPs, five are located in promoter regions, three of them are in putative transcription factor binding sites (TFBSs) of the CSN1S2 promoter. Fifteen SNPs potentially affect miRNA target sites. In a second step, 50 unrelated Butana cattle were genotyped. This allowed deriving haplotypes for the casein gene cluster on BTA6. The most frequent haplotype was CSN1S1*C-CSN2*A 2 -CSN1S2*A-CSN3*A (C-A 2 -A-A, frequency 0.1546). Considering the newly identified CSN1S2 promoter variants, the most frequent haplotype was C-A 2 -TTC-A-A (0.1046), with TTC as the promoter variant. The information on protein and promoter variants can be used for the development of conservation and breeding strategies for this local breed.

Genome-wide associations for investigating time-dependent genetic effects for milk production traits in dairy cattle.

Phenotypic variation in milk production traits has been described over the course of a lactation as well as between different parities. The objective of this study was to investigate whether variation in production is affected by different loci across lactations. A genome-wide association study (GWAS) using a 50-k SNP chip was conducted in 152 divergent German Holstein Friesian cows to test for association with milk production traits over different lactations. The first four lactations were analysed regarding milk yield, fat, protein, lactose, milk urea nitrogen yield and content as well as somatic cell score. Two approaches were used: (i) Wilmink curve parameters were used to assess the genetic effects over the course of a lactation and (ii) test-day yield deviations (YD) were used as a normative approach for a GWAS. The significant effects were largest for markers affecting curve parameters for which there was a statistical power <0.8 of detection even in this small design. While significant markers for YDs were detected in this study, the power to detect effects of a similar magnitude was only 0.11, suggesting that many loci may have been missed with this approach in the present design. Furthermore, all significant effects were specific for a single lactation, leading to the conclusion that the variance explained by a certain locus changes from lactation to lactation. We confirm the common evidence that most production traits vary in the degree of persistency after the peak as a result of genetic influence.

Modeling of the U1 snRNP assembly pathway in alternative splicing in human cells using Petri nets.

The investigation of spliceosomal processes is currently a topic of intense research in molecular biology. In the molecular mechanism of alternative splicing, a multi-protein-RNA complex - the spliceosome - plays a crucial role. To understand the biological processes of alternative splicing, it is essential to comprehend the biogenesis of the spliceosome. In this paper, we propose the first abstract model of the regulatory assembly pathway of the human spliceosomal subunit U1. Using Petri nets, we describe its highly ordered assembly that takes place in a stepwise manner. Petri net theory represents a mathematical formalism to model and analyze systems with concurrent processes at different abstraction levels with the possibility to combine them into a uniform description language. There exist many approaches to determine static and dynamic properties of Petri nets, which can be applied to analyze biochemical systems. In addition, Petri net tools usually provide intuitively understandable graphical network representations, which facilitate the dialog between experimentalists and theoreticians. Our Petri net model covers binding, transport, signaling, and covalent modification processes. Through the computation of structural and behavioral Petri net properties and their interpretation in biological terms, we validate our model and use it to get a better understanding of the complex processes of the assembly pathway. We can explain the basic network behavior, using minimal T-invariants which represent special pathways through the network. We find linear as well as cyclic pathways. We determine the P-invariants that represent conserved moieties in a network. The simulation of the net demonstrates the importance of the stability of complexes during the maturation pathway. We can show that complexes that dissociate too fast, hinder the formation of the complete U1 snRNP.

[Effects of endurance training on left ventricular filling dynamics: a study using stress Doppler echocardiography]. / Auswirkungen des Ausdauertrainings auf die linksventrikuläre Füllungsdynamik: Eine Untersuchung mittels Stress-Dopplerechokardiographie.

To evaluate the impact of endurance training on left-ventricular (LV) filling dynamics Doppler mitral flow was derived in 23 amateur endurance-trained athletes (AT) aged 31 (24-39) years with a personal marathon record greater than or equal to 200 min, and in 20 ultra-endurance athletes (UEA) aged 38 (28-42) years with a personal marathon record less than 200 min during bicycle exercise in supine position. Twenty-two untrained healthy volunteers (UT) aged 27 (24-30) years served as control. In particular, atrial filling fraction (AFF) as the relative share of atrial contribution to LV filling was measured. At rest AFF was significantly higher in UT (29%) as compared to AT (25%) and UEA (25%). During exercise (150 watt) atrial fraction increased significantly more in UT (37%) as compared to AT (34%) and UEA (29%) (p less than 0.01). At this point of measurement UEA had significantly lower values for AFF than AT (p less than 0.001). Two min post exercise atrial filling fraction already reached baseline values in UEA (24%) and AT (26%), while it remained significantly elevated in UT as compared to baseline values (38%, p less than 0.001). Ten min post exercise atrial filling fraction showed still elevated values in UT (32%), but decreased under baseline values in UEA (23%). No differences in heart rate between the two athlete groups at all times of measurement were observed. Thus, while atrial filling fraction rose in all study groups during exercise, it returned earlier to baseline values in athletes than in untrained subjects. This indicates a better cardiac adaptation to physical stress and a better diastolic performance during exercise in endurance-trained athletes, being even more pronounced in ultra-endurance athletes.

Changes of diastolic function induced by cigarette smoking: an echocardiographic study in patients with coronary artery disease.

In 28 chronic smokers (11 women, 17 men, 53 +/- 10 years old) with coronary artery disease (greater than 75% stenosis), left ventricular (LV) relaxation and filling behavior was assessed before and after inhalation of 0.9 mg nicotine (1 cigarette) by echocardiography. The following acute nicotine-mediated changes were noted (one-sided Wilcoxon test): heart rate increased from 67 to 81 beats/min (p greater than .001); the early diastolic flow (E wave) integral decreased from 49 to 39 mm (p less than .001); the late diastolic flow integral (A wave) increased from 36 to 41 mm (p less than .01). Consecutively, the ratio between E and A wave flow integrals decreased from 1.4 to 0.9 (p less than .001); the atrial contribution to LV filling rose from 42 to 53% (p less than .001); and the isovolumetric relaxation period increased from 89 to 122 ms (p less than .001). In cigarette smokers with coronary artery disease acute administration of nicotine hence causes a shift of mitral blood flow from early (E wave) to late (A wave) diastole and a prolongation of the isovolumetric relaxation time. Thus, cigarette smoking significantly affects LV diastolic function independently of its role as a risk factor for coronary atherosclerosis.