Effects of a single phosphate-enriched test meal on inflammasome activity and postprandial inflammatory markers in healthy subjects

PURPOSE

The consumption of highly processed food is often associated with a high intake of inorganic phosphate. Hyperphosphatemia is accompanied by an inflammatory status in patients with chronic kidney disease. However, the immune response to high phosphorus intake in healthy individuals is largely unknown. Therefore, the aim of the present study was to evaluate the effect of a single phosphate-enriched meal on inflammasome activity and plasma levels of inflammatory markers.

METHODS

The analysis included 28 participants who received a single dose of either 700 mg phosphorus or a placebo with a test meal. At baseline, 4 and 8 h post-meal, plasma interleukin (IL)-6, IL-1β, IL-10, c-reactive protein (CRP), soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (sgp130) levels were determined. At baseline and 4 h post-meal, peripheral blood mononuclear cells were isolated to assess inflammasome activity. Subsequently, the effect of phosphate with or without glucose on IL-6 and IL-1β gene expression and secretion in U937 monocytes was examined.

RESULTS

While both groups showed a marked postprandial increase in IL-6 plasma levels, neither plasma levels of IL-6, IL-1β, CRP, IL-10, sIL-6R, and sgp130 nor inflammasome activity were affected by phosphate compared to placebo. In U937 cells, there was also no effect of phosphate on IL-6 expression, but the addition of glucose increased it. Phosphate, however, reduced the IL-1β secretion of these cells.

CONCLUSION

Postprandial inflammatory markers were not affected by dietary phosphate. However, IL-6 plasma levels were markedly increased post-meal, which appears to be a metabolic rather than a pro-inflammatory phenomenon.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT03771924, date of registration: 11th December 2018, retrospectively registered.

Changes in Composition and Diversity of Epiphytic Microorganisms on Field Pea Seeds, Partial Crop Peas, and Whole Crop Peas during Maturation and Ensiling with or without Lactic Acid Bacteria Inoculant

The present study was conducted under the hypothesis that, in field peas, type of plant material, stage of maturity, ensiling, silage additive, and aerobic stress affect the composition and diversity of epiphytic microbial communities. Epiphytic microbial composition and diversity of pea seeds, partial crop peas, and whole crop peas was analyzed at different stages of late maturity, before and after ensiling, and with or without the use of lactic acid bacteria (LAB) as inoculant. Suitable combinations among pea crop variants, maturity stages, and inoculant use for the production of stable silages with sufficient aerobic stability after opening and during feed-out were identified. Genomic DNA was extracted, and 16S and 18S rRNA gene amplicons were sequenced. To assess the quality of the various silages, nutrient concentration, pH value, concentration of lactic acid, short chain fatty acids, and alcohols, and aerobic stability were determined. Pea seeds were barely colonized by epiphytic microorganisms. In partial and whole crop peas, composition and α-diversity (Shannon index) of bacterial communities did not differ between crop variants but differed among maturity stages. Epiphytic eukaryotes were rarely found on partial and whole crop peas. Bacterial composition and α-diversity were affected by ensiling and subsequent aerobic storage. In partial and whole crop peas, plant maturation caused an increase of the relative abundance of naturally occurring LAB (Weissella, Pediococcus, and Lactobacillus spp.). As a possible result, natural LAB support stable ensiling conditions even without the use of inoculants beginning with a maturity of 78 on the BBCH scale. This corresponded with a dry matter (DM) concentration of 341 and 363 g/kg in partial and whole crop peas, respectively. Addition of LAB inoculants, however, reduced ammonia, acetic acid, and butanol concentrations, and supported aerobic stability. Earlier stages of plant maturity (BBCH 76 and 77, 300 g DM/kg or less) were more prone to microbial spoilage. Stable pea seed silages can be produced at a maturity between BBCH 78 (427 g DM/kg) and 79 (549 g DM/kg), but they undoubtedly require LAB inoculation or application of other ensiling agents. IMPORTANCE Field peas are important protein suppliers for human and animal nutrition. They can be grown in many areas of the world, which may reduce imports of protein plants and has beneficial economic and ecological effects. Ensiling is a method of preserving feed that can be implemented easily and cost-effectively at the farm. Peas harvested as seeds, partial crop, or whole crop at different maturities enable a wide range of applications. The study characterized epiphytic microbial communities on peas in terms of composition and diversity depending on the maturity of the plants and feed conservation by ensiling as they play an essential role for the production of silages. Even if this study did not consider year, site, or cultivar effects, the results would show which part of the plant is probably well suited for the production of stable and high-quality silages and at which stage of maturity.

Functional Variants Associated With CMPK2 and in ASB16 Influence Bovine Digital Dermatitis

Bovine digital dermatitis (BDD) is an infectious disease of the hoof in cattle with multifactorial etiology and a polygenic influence on susceptibility. With our study, we identified genomic regions with the impact on occurrence and development of BDD. We used 5,040 genotyped animals with phenotype information based on the M-stage system for genome-wide association. Significant associations for single-nucleotide polymorphisms were found near genes CMPK2 (chromosome 11) and ASB16 (chromosome 19) both being implicated in immunological processes. A sequence analysis of the chromosomal regions revealed rs208894039 and rs109521151 polymorphisms as having significant influence on susceptibility to the disease. Specific genotypes were significantly more likely to be affected by BDD and developed chronic lesions. Our study provides an insight into the genomic background for a genetic predisposition related to the pathogenesis of BDD. Results might be implemented in cattle-breeding programs and could pave the way for the establishment of a BDD prescreening test.

Lying, Feeding and Activity Preference of Weaned Piglets for LED-Illuminated vs. Dark Pen Compartments

Simple Summary

Knowledge about animal welfare-based lighting in pig farms is very limited, as there is little research on this topic. Legal requirements are often not scientifically supported and differ greatly among countries. However, negative effects of uncontrolled lighting on pig health and behaviour are known. In this study, the influence of different illuminance levels on the preference behaviour of pigs was determined. Piglets were given a free choice between two illuminance levels. We found that over time piglets preferred darker pen compartments to lie down and brightly lit ones to move around and defaecate. This knowledge could be used for future farm husbandry design and promotes the natural behaviour of pigs, thus reducing stress and promoting animal welfare.

Abstract

Little is known on the effect of light on pig behaviour. The choice behaviour of weaned piglets kept under two different light-emitting diode (LED) illuminance levels was investigated: 32 piglets (in two batches) were housed in a preference test room composed of two identical double pen units. One side of the pen unit was permanently illuminated with 600 lux, while the other was darkened to almost 0 lux (~0 lx); by using a passageway, piglets could move between the two sides. The “lying”, “eating” and “activity” behaviours were evaluated during three days in the first, third and fifth experimental week based on video recordings and a 5-min time sampling method. At first, piglets preferred to stay in the 600 lux illuminated compartments. Then, this preference decreased for the “eating” and “activity” behaviours and reversed for the “lying” behaviour, with the darkened compartments being preferred. The results also show that pen soiling was higher under 600 lux, but feed consumption was not affected by the illuminance. Since pigs choose between the two illuminance levels to perform specific behaviours, illuminance could be used to divide the pens into functional areas and, thus, help in meeting pigs’ behavioural needs.

The effects of a training program using a phantom to accustom heifers to the automatic milking system

The introduction of heifers into the automatic milking system (AMS) can be associated with considerable stress for both animals and farm employees, as completely inexperienced heifers initially do not independently enter the unknown milking robot. This study investigated whether training heifers on an AMS phantom provides the possibility of preparing heifers for the following lactation at the AMS. For this purpose, 77 Holstein-Friesian heifers were randomly assigned to one of 2 experimental groups: control (CON) or phantom (PHAN). Four weeks before calving, the PHAN group was given free access to the phantom, which was similar to the actual milking robot, so that they could explore it and be positively conditioned by feeding concentrate in the phantom. The heifers of the CON group had no contact with the phantom or the AMS before the first milking at the AMS. The milking frequency per animal per day was recorded, and the proportion of animals that had to be fetched for milking was determined, to evaluate how the animals accepted the AMS after calving. To assess the stress level of the animals before and after introduction into the AMS, fecal cortisol concentrations and rumination times of the animals were measured. Additionally, lactation performance characteristics (milk yield, milk flow, electrical conductivity of milk, and milk composition) were recorded for 77 animals. The animals trained on the phantom showed a higher milking frequency (DIM 7: 2.70 ± 0.14 visits/d) than the control animals (DIM 7: 2.41 ± 0.14 visits/d) between the 4th and 10th day of lactation. In addition, between d 1 and d 5, the proportion of animals that had to be fetched for milking was lower in PHAN (DIM 1: 35.18 ± 4.16%) than in CON (DIM 1: 48.03 ± 4.46%). The PHAN heifers had unexpectedly high fecal cortisol levels (1 wk prepartum: 43.50 ± 0.93 ng/g of feces), although not considerably elevated compared with CON (1 wk prepartum: 40.76 ± 1.05 ng/g of feces). Training on the phantom had no appreciable influence on rumination time and lactation performance parameters. The increased number of milking visits and the reduced proportion of animals that had to be fetched into the AMS for milking indicate that training on the phantom prepares the animals well for being milked in the AMS. Therefore, training heifers on the phantom offers the possibility to facilitate the start into early lactation for the animals, providing a valuable contribution to improvement of animal welfare.

Differential effects of vitamin D3 vs vitamin D2 on cellular uptake, tissue distribution and activation of vitamin D in mice and cells

To combat vitamin D deficiency, vitamin D₃ and vitamin D₂ are commonly used as a supplement or to fortify food sources. Human data show that the response of 25-hydroxyvitamin D (25(OH)D) to supplementation with vitamin D₃ is higher than to vitamin D₂. To elucidate the metabolic route of both vitamers, we conducted a study with vitamin D-depleted mice, which were allotted into three groups (n = 12) and received equal doses of either deuterated vitamin D₃, deuterated vitamin D₂ or both for 4 weeks. To further investigate the hepatic uptake and hydroxylation of both D-vitamers to 25(OH)D, we conducted cell culture experiments with murine and human hepatoma cells (Hepa1-6 and HepG2). The vitamin D metabolite concentrations in serum, tissues and cells were analyzed by LC-MS/MS or ELISA. In mice, vitamin D₂ resulted in lower serum and tissue concentrations of vitamin D (P < 0.001) than vitamin D₃, while the group which received both D-vitamers showed values in between. Interestingly, vitamin D₂ fed mice had 1.9-times and 2.9-times higher serum concentrations of total and free 25(OH)D (P < 0.001) than mice fed vitamin D₃, while the concentration of 1,25-dihydroxyvitamin D (1,25(OH)₂D) was 1.8-times lower (P < 0.001). The gene and protein expression of enzymes, involved in the hydroxylation and renal uptake of vitamin D remained largely unaffected by the D-vitamer. In contrast to the mice data, hepatoma cells preferred vitamin D₃ for 25-hydroxylation over vitamin D₂ (P < 0.001). In general, the formation of 25(OH)D was much more pronounced in human than in murine hepatoma cells (P < 0.001). To conclude, in contrast to humans, vitamin D₂ was more efficient in increasing 25(OH)D than vitamin D₃ in mice, although this difference was not caused by a preferential hydroxylation of vitamin D₂ in the liver. The metabolic routes of D₃ and D₂ in mice differ, showing lower circulating 1,25(OH)₂D and tissue vitamin D concentrations in D₂- than in D₃-fed mice.

Feasibility of artificial light regimes to increase the vitamin D content in indoor-laid eggs

Vitamin D insufficiency is prevalent worldwide. Recently, we showed that exposure of laying hens to sunlight or artificial ultraviolet B (UVB) light is an efficient strategy to increase the vitamin D content in eggs. In the current study, using 2 different chicken genotypes and stocking densities, we addressed the question of whether different UVB-emitting regimes work under real indoor housing conditions in a floor system or in furnished cages. Here, we found a 3.7-fold increase in the egg vitamin D content in Lohmann Selected Leghorn hens and a 4.2-fold increase in Lohmann Brown hens after UVB exposure for 6 h/d. The data further reveal that UVB exposure under high stocking density is equally effective compared to that at low stocking density. The different light regimes were not associated with changes in the behavior of these animals. To conclude, artificial UVB-emitting light regimes are a practical strategy to increase the vitamin D content in indoor-laid eggs.

Interdigital Hyperplasia in Holstein Cattle Is Associated With a Missense Mutation in the Signal Peptide Region of the Tyrosine-Protein Kinase Transmembrane Receptor Gene

Bovine interdigital hyperplasia (IH) is a typical disease of the foot with varying prevalence depending on age, breed, and environmental factors resulting in different degrees of lameness. In studies based on assessments of claw health status at time of hoof trimming and applying genetic-statistical models to analyze this data, IH consistently exhibits high estimates of heritability in the range of 0.30–0.40. Although some studies have identified chromosomal regions that could possibly harbor causative genes, a clear identification of molecular causes for IH is lacking. While analyzing the large database of claw health status as documented at time of hoof trimming, we identified one herd with extreme prevalence of IH of > 50% of affected Holstein dairy cows. This herd subsequently was chosen as the object of a detailed study. A total of n = 91 cows was assessed and revealed a prevalence of 59.3% and 38.5% for IH cases, documented as “one-sided” or “two-sided”, respectively. Cows were genotyped using the BovineSNP50 BeadChip. A genome wide association study revealed two significantly associated chromosomal positions (-log₁₀P = 5.57) on bovine chromosome 8 (BTA8) located in intron 5 and downstream of the receptor tyrosine kinase-like orphan receptor 2 (ROR2) gene. As ROR2 plays a key role in ossification of the distal limbs and is associated with brachydactylies in humans, it was a reasonable candidate for IH. A comparative sequencing of the ROR2 gene between cases and controls revealed two missense variants in exon 1 (NC_037335.1:g.85,905,534T > A, ARS-UCD1.2) and exon 9 (NC_037335.1:g.86,140,379A > G, ARS-UCD1.2), respectively. Genotyping of both variants in the cohort of 91 cattle showed that the exon 1 variant (rs377953295) remained significantly associated with IH (p < 0.0001) as a risk factor of the disease. This variant resulted in an amino acid exchange (ENSBTAP00000053765.2:p.Trp9Arg) in the N-terminal region of the ROR2 signal peptide which is necessary for proper topology of the polypeptide during translocation. Quantification of ROR2 mRNA and ROR2 protein showed that the variant resulted in a significant suppression of ROR2 expression in homozygous affected compared to wild type and carrier cows.

Modification of the equine gastrointestinal microbiota by Jerusalem artichoke meal supplementation

The objective of this study was to investigate the impact of natural prebiotic active compounds on the microbial composition in different regions of the equine gastrointestinal tract. Twelve adult horses (body weight [bwt] 534 ± 64.5 kg; age 14 ± 7.5 years) were randomly divided into two feeding groups. Six horses received a basal diet consisting of 1.5 kg hay/100 kg bwt x d^-1 and oat grains equal to 1.19 g starch/kg bwt x d^-1, supplemented with Jerusalem artichoke meal providing prebiotic fructooligosaccharides + inulin in a quantity of 0.15 g/kg bwt x d^-1. The remaining horses received a placebo added to the basal diet. The horses were fed for 21 d and euthanized at the end of the feeding period. Digesta samples from different parts of the gastrointestinal tract were taken, DNA extracted and the V1-V2 region of the 16S rRNA gene amplified. Supplementation with the prebiotic increased the relative abundance of Lactobacillus (P < 0.05), with a concurrent reduction of the relative abundance of Streptococcus mainly in the stomach (P < 0.05). In the hindgut, the supplemental prebiotic also increased the relative abundance of Lactobacillus but further reduced the relative abundance of fibrolytic bacteria, specifically the unclassified members of the families Lachnospiraceae (P < 0.05) and Ruminococcaceae. The relative abundance of the genus Ruminococcus increased solely in the caecum and colon transversum. Overall, the addition of the prebiotic significantly increased the diversity in nearly all parts of the gastrointestinal tract (P < 0.05). The feeding of this natural prebiotic compound to horses had an impact on the microbial community in the entire gastrointestinal tract. Furthermore, the effect on the bacterial community in the foregut (especially the stomach) was more pronounced in comparison to the effect in the hindgut. Therefore, the impact on stomach health should be carefully considered.

Chewing patterns in horses during the intake of variable quantities of two pelleted compound feeds differing in their physical characteristics only

Pelleted feeds (PF) are popular in horse nutrition because of high palatability and improved feeding hygiene, but ingestion is faster for PF than for cereals or muesli feed. The aim of the study was to evaluate whether variable amounts of two PFs produced with different physical properties from the same batch of feed can affect feed intake patterns in horses. Chewing patterns were measured in six warmblood mares (519 ± 36.3 kg) on two PFs (small-sized PF1: ø 5 mm, length 21.9 ± 4.97 mm, large-sized PF2: edge length 15.6 ± 0.14 × 15.6 ± 0.08 mm, length 54.4 ± 9.59 mm) in three different amounts (1.0, 1.5, 2.0 kg) once per day additional to hay. PF 2 was ingested faster than PF1 for the meal size 1.0 kg, but PF 1 was ingested more rapidly with a reduced chewing intensity if the offered meal size increased. The ingestion of PF 2 tendentially elevated the chewing intensity at higher meal sizes. An additional, but inverted meal size effect compared to 1.0 kg, was observed for 1.5 kg, where PF 1 was ingested at a higher speed combined with a lower chewing intensity compared to PF 2. Independent from the offered amount, PF 2 induced a markedly increased saliva production combined with a higher daily water intake. Larger-sized pellets seem to intensify the chewing process and decelerate the ingestion time if the meal size becomes larger.

Feed Intake Patterns and Immediate Glycaemic and Insulinaemic Responses of Horses Following Ingestion of Different Quantities of Starch From Oat, Barley and Grains

Background:

Relevant literature indicate that more than 0.8 g starch/kg body weight from compounded feed composed of different starch sources induces disproportionate glycaemic and insulinaemic responses in horses.

Objective:

It should be investigated whether crushed oats, barley and maize also cause a disproportionate increase in plasma glucose and insulin when fed as the only concentrate in quantities equal to and above 0.8 g starch/kg body weight.

Method:

Four mares received hay plus oats, barley and maize, respectively, in quantities equal to 0.8, 1.0 and 2.0 g starch/kg body weight. At the test days, chewing parameters were detected and blood sampled before and 30, 60, 90 and 120 min after the concentrate meal. Plasma glucose and insulin were measured and areas under the curve were calculated.

Results:

Maize was ingested particularly slowly (dry matter basis; P < 0.05), but glycaemic and insulinaemic responses were particularly low (starch basis; P < 0.05). In general, the glycaemic responses were highest with 1 g starch/kg body weight (P < 0.05). The quantity of starch had no effect on the insulinaemic response (P > 0.05). A defined increase in plasma glucose induced the highest insulinaemic response with oat grains.

Conclusion:

Oats and barley are ingested faster and induce higher glycaemic and insulinaemic responses than maize. Until 120 min postprandial, elevated quantities of starch from these grains seem to induce no disproportionate or at least linear increase of plasma glucose and insulin. The insulinaemic response to a defined increase of plasma glucose is particularly pronounced with oats.

Effects of isoenergetic quantities of a low-starch muesli feed high in fat and fibre vs. oat grains on the glycemic and insulinemic responses and feed intake patterns in sport ponies

Aim of this study was to compare glycemic and insulinemic responses and feed intake patterns in sport ponies after feeding isoenergetic quantities of low-starch muesli feed high in fat and fibre (FF) or oat grains (OG). Six sport ponies were randomly assigned to one of these two treatment groups for 2 × 3 weeks according to a crossover-design. Ponies received two equal meals/day of either semi-crushed OG (1 g starch/kg bwt*meal^-1 ) or an isoenergetic quantity of FF. Hay was also given in two equal meals/day and provided the remaining metabolisable energy up to 1.3-fold maintenance level. On day 21, blood was sampled 1 h after each pony received 0.5 kg hay (0 min). Then, the concentrate was provided and blood sampled 30, 60, 90, 120, 180, 240 and 300 min thereafter. Plasma glucose and serum insulin were analysed, and the areas under the curve (AUC) was calculated 120 and 300 min postprandial (PP). Feed intake patterns were measured in 4 ponies/group via a modified halter. OG was ingested faster than FF (feed intake time; FIT_DM in min/kg DM: 8.8 ± 1.6 vs. 15.9 ± 1.62, p < 0.05) combined with a higher chewing frequency (p < 0.05). The AUCs_{gluc120/300, ins120/300} were statistically higher with OG than FF (mmol/L*min^-1 : AUC_gluc120 : 776 ± 128 vs. 676 ± 80.4; AUC_gluc300 : 1811 ± 295.3 vs. 1569 ± 126.3; nmol/L*min^-1 : AUC_ins120 : 38 ± 18 vs. 22 ± 8.1; AUC_ins300 : 83 ± 39 vs. 35 ± 12; p < 0.05). Plasma glucose tended to decline following the intake of FF, which might be beneficial for equines with reduced glucose tolerance. This, however, requires further investigation. In this study, the ponies consumed OG unexpectedly rapidly. The rate of feed intake was similar to the results previously reported in the literature for warmblood horses.

Evaluation of breeding strategies for polledness in dairy cattle using a newly developed simulation framework for quantitative and Mendelian traits

Background

Intensified selection of polled individuals has recently gained importance in predominantly horned dairy cattle breeds as an alternative to routine dehorning. The status quo of the current polled breeding pool of genetically-closely related artificial insemination sires with lower breeding values for performance traits raises questions regarding the effects of intensified selection based on this founder pool.

Methods

We developed a stochastic simulation framework that combines the stochastic simulation software QMSim and a self-designed R program named QUALsim that acts as an external extension. Two traits were simulated in a dairy cattle population for 25 generations: one quantitative (QMSim) and one qualitative trait with Mendelian inheritance (i.e. polledness, QUALsim). The assignment scheme for qualitative trait genotypes initiated realistic initial breeding situations regarding allele frequencies, true breeding values for the quantitative trait and genetic relatedness. Intensified selection for polled cattle was achieved using an approach that weights estimated breeding values in the animal best linear unbiased prediction model for the quantitative trait depending on genotypes or phenotypes for the polled trait with a user-defined weighting factor.

Results

Selection response for the polled trait was highest in the selection scheme based on genotypes. Selection based on phenotypes led to significantly lower allele frequencies for polled. The male selection path played a significantly greater role for a fast dissemination of polled alleles compared to female selection strategies. Fixation of the polled allele implies selection based on polled genotypes among males. In comparison to a base breeding scenario that does not take polledness into account, intensive selection for polled substantially reduced genetic gain for this quantitative trait after 25 generations. Reducing selection intensity for polled males while maintaining strong selection intensity among females, simultaneously decreased losses in genetic gain and achieved a final allele frequency of 0.93 for polled.

Conclusions

A fast transition to a completely polled population through intensified selection for polled was in contradiction to the preservation of high genetic gain for the quantitative trait. Selection on male polled genotypes with moderate weighting, and selection on female polled phenotypes with high weighting, could be a suitable compromise regarding all important breeding aspects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-016-0228-7) contains supplementary material, which is available to authorized users.

Short communication: A comparison between purebred Holstein and Brown Swiss × Holstein cows for milk production, somatic cell score, milking speed, and udder measurements in the first 3 lactations

Brown Swiss × Holstein (BS × HO) crossbred cows (n = 55) and purebred Holstein (HO) cows (n = 50) were compared for milk yield, fat and protein production, somatic cell score, milking speed, and udder measurements for the first 3 lactations. Cows from a designed experiment were housed in a freestall barn at the experimental station of the federal state of Saxony-Anhalt, Germany, and calved from July 2005 to August 2008. Best prediction was used to determine actual production for 305-d lactations from test-day observations. For the first 3 lactations, BS × HO cows and HO cows were not significantly different for milk yield, fat and protein production, or SCS. Average milking time was significantly longer for BS × HO cows than for HO cows for first, second, and third lactations by 35, 51, and 30s, respectively. Average milking speed expressed as average yield per minute was significantly lower for BS × HO cows than for HO cows for the first 3 lactations by 0.19, 0.35, and 0.19 kg/min, respectively. Front and rear teats were significantly longer for BS × HO cows than for HO cows. Furthermore, front and rear udder clearance was significantly lower for BS × HO cows compared with HO cows in first and second lactations.

Identification of candidate genes for congenital splay leg in piglets by alternative analysis of DNA microarray data

The congenital splay leg syndrome in piglets is characterized by a temporarily impaired functionality of the hind leg muscles immediately after birth. Etiology and pathogenetic mechanisms for the disease are still not well understood. We compared genome wide gene expression of three hind leg muscles (M. adductores, M. gracilis and M. sartorius) between affected piglets and their healthy littermates with the GeneChip Porcine Genome Array (Affymetrix) in order to identify candidate genes for the disease. Data analysis with standard algorithms revealed no significant differences between both groups. By application of an alternative approach, we identified 63 transcripts with differences in two muscles and 5 genes differing between the groups in three muscles. The expression of six selected genes (SQSTM1, SSRP1, DDIT4, ENAH, MAF, and PDK4) was investigated with SYBRGreen RT-Real time PCR. The differences obtained with the microarray analysis could be confirmed and demonstrate the validity of the alternative approach to microarray data analysis. Four genes with different expression levels in at least two muscles (SQSTM1, SSRP1, DDIT4, and MAF) are assigned to transcriptional cascades related to cell death and may thus indicate pathways for further investigations on congenital splay leg in piglets.

Varianzkomponentenschätzung unter Berücksichtigung von Dominanz an simulierten Reinzuchtlinien

Abstract. Title of the paper: Estimation of variance components under dominance with simulated purebred lines A stochastic simulation based on a gene model was used to investigate the estimation of variance with dominance and additive animal models. For a heritability in broad sense of 0.5 three ratios of dominance variance (5, 10 and 25%) on the phenotypic variance were investigated under different degrees of dominance. No additionally biased estimations of the variance components as consequence of different dominance degrees were found. By using the dominance model for random mating as well as for selection the differences between true parameters and estimation values were small for all dominance degrees and ratios of dominance variance. Small, but significantly, differences can be explained by the change of the allele frequencies over the generations due to the influence of selection. By using the additive animal model, that ignores the dominance relationship, for high ratios of the dominance variance (25% or greater) important biased estimations of the variances were observed. For dominance ratios of 5% no significantly overestimation of the additive variances with the reduced model were found under selection and random mating.

Optimierung von Zuchtstrukturen einer Zweilinienkreuzung – Eine Monte-Carlo Studie

Abstract. Title of the paper: Optimization of the population structure for a two-line crossbreeding scheme – a Monte-Carlo study A stochastic simulation was used to optimize the population structure in a two-line crossbreeding system under non-additive gene models. For different fixed test capacities, given number of offspring per dam and varying degrees of dominance the optimum number of selected sires was calculated. As criterions of the optimization the cumulative selection response on generation 10, the corresponding standard error of the response and the development of the inbreeding in the purebreds were used. If the trait was controlled by loci with partial and complete dominance, than the optimal number of selected sires was between 8 and 12 for given test capacities of 2304, 1152 and 1536 animals per generation and per the sire line. In the case of overdominance the number of selected sires increased on 24 to 48. Additionally, the level of the selection response in the three populations was affected by the difference of the allele frequencies in the initial generation and the economic weights of the additive purebred and crossbred effects. Under partial and complete dominance with corresponding purebred-crossbred genetic correlations of high and moderate level only small extra benefits were obtained from including crossbred information over pure line information.