Short communication: influence of the muscle hypertrophy mutation of the myostatin gene on milk production traits and milk fatty acid composition in dual-purpose Belgian Blue dairy cattle.

The objective of this study was to estimate genetic effects for the muscle hypertrophy mutation (mh) of the myostatin gene for conventional milk production traits and for milk fatty acid composition in dual-purpose Belgian Blue dairy cows. For the present study, only cows from a single herd, in which genotype frequencies were as balanced as possible (0.266 for +/+, 0.523 for mh/+, and 0.211 for mh/mh), were chosen to avoid confounding between herd and genotype effects. A total of 109 cows with 3,190 test-day records for fat, protein, and milk yields and 1,064 test-day records for saturated and monounsaturated fatty acids were used for the calculations. Variance component and gene effect estimations were performed via expectation-maximization REML and BLUP methods, respectively, using a multi-trait mixed test-day model with an additional fixed regression on the muscle hypertrophy genotype. Results showed that one copy of the wild-type "+" allele led to a significant additive effect of 26.35 g/d for fat yield. Significant dominance effects of 23.22 g/d for protein yield and 30.28 g/d for fat yield were also observed. In contrast, a nonsignificant trend was observed in favor of lower saturated fatty acid contents in milk for one copy of the mutant "mh" allele. Concerning milk, fat, and protein yields, our results confirmed literature results indicating a superior effect of the "+" allele compared with the mutant allele. Therefore, the selection of the "+" allele has the potential to increase conventional milk production traits in the dual-purpose Belgian Blue breed. However, when focus is given to milk fatty acid profile, a possible antagonistic effect between the benefit of the "+" allele for higher milk production and the "mh" allele for reduced saturated fatty acid content in milk should be confirmed in further studies.

Estimating myostatin gene effect on milk performance traits using estimated gene content for a large number of non-genotyped cows.

The objective of this study was to estimate the myostatin (mh) gene's effect on milk, protein and fat yield in a large heterogeneous cow population, of which only a small portion was genotyped. For this purpose, a total of 13 992 889 test-day records derived from 799 778 cows were available. The mh gene effect was estimated via BLUP using a multi-lactation, multi-trait random regression test-day model with an additional fixed regression on mh gene content. As only 1416 animals, (of which 1183 cows had test-day records) were genotyped, more animals of additional breeds with assumed known genotype were added to estimate the genotype (gene content) of the remaining cows more reliably. This was carried out using the conventional pedigree information between genotyped animals and their non-genotyped relatives. Applying this rule, mean estimated gene content over all cows with test-day records was 0.104, showing that most cows were homozygous +/+. In contrast, when gene content estimation was only based on genotyped animals, mean estimated gene content over all cows with test-day records was with 1.349 overestimated. Therefore, the applied method for gene content estimation in large populations needs additional genotype assumptions about additional animals representing genetic diversity when the breed composition in the complete population is heterogeneous and only a few animals from predominantly one breed are genotyped. Concerning allele substitution effects for one copy of the 'mh' gene variant, significant decreases of -76.1 kg milk, -3.6 kg fat and -2.8 kg protein/lactation were obtained on average when gene content estimation was additionally based on animals with assumed known genotype. Based on this result, knowledge of the mh genotypes and their effects has the potential to improve milk performance traits in cattle.

A robust method for simultaneous estimation of single gene and polygenic effects in dairy cows using externally estimated breeding values as prior information.

The aim of this study was to develop a robust method to estimate single gene and random polygenic animal effects simultaneously in a small field dataset with limited pedigree information. The new method was based on a Bayesian approach using additional prior information on the distribution of externally estimated breeding values. The field dataset consisted of 40,269 test-day records for milk performance traits for 1455 genotyped dairy cows for the 11 bp-deletion in the coding sequence of the myostatin gene. For all traits, estimated additive effects of the favoured wild-type allele ('+' allele) were smaller when applying the new method in comparison with the application of a conventional mixed inheritance test-day model. Dominance effects of the myostatin gene showed the same behaviour but were generally lower than additive effects. Robustness of methods was tested using a data-splitting technique, based on the correlation of estimated breeding values from two samples, with one-half of the data eliminated randomly from the first sample and the remaining data eliminated from the second sample. Results for 100 replicates showed that the correlation between split datasets when prior information included was higher than the conventional method. The new method led to more robust estimations for genetic effects and therefore has potential for use when only a small number of genotyped animals with field data and limited pedigree information are available.

Detection of novel single-nucleotide polymorphisms (SNPs) in the CYP21 gene and association analysis of two SNPs for CYP21 and ESR2 with litter size in a commercial sow population.

Altogether 129 F1 sows from a commercial sow farm with at least four litters were genotyped for the oestrogen receptor 2 gene (ESR2) and cytochrome P450 hydroxylase 21 gene (CYP21) and investigated for associations on the litter-size parameters: total number born and number born alive. Five novel polymorphisms were found in the 3'-untranslated region for the CYP21 gene. Genotype and allele frequencies for the CYP21 (position 3462G > A) single-nucleotide polymorphism (SNP) were 0.434 (GG), 0.504 (AG), 0.062 (AA) and 0.69 (G):0.31 (A), respectively. No association was found between this polymorphism and litter-size parameters. For the ESR2 gene, the SNP in exon 5 associated with an amino acid substitution MET (allele A) > VAL (allele G) was investigated. Only two genotypes were found leading to allele frequencies of 0.34 (A):0.66 (G). Only number born alive piglets were significantly increased for the AG genotype (p = 0.034) with 11.64 piglets per sow and litter in comparison with the GG genotype, leading to only 10.96 piglets per sow and litter. From these data, it can be concluded that the investigated SNP of the ESR2 gene is associated with the number of liveborn piglets in the commercial population considered, and hence could be useful in selection for litter size. Therefore, this gene should be investigated in additional populations.

Analysis of properdin (BF) genotypes associated with litter size in a commercial pig cross population.

Properdin (BF) was investigated as a candidate gene influencing litter size in a commercial pig cross population. The BF gene was chosen because of its integral role in influencing uterine epithelium growth and because several quantitative trait loci (QTL) with impact on reproductive traits have been detected near the centromere of porcine chromosome 7. A total of 123 F2 (Large White x Landrace) x Leicoma sows were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The sows were divided into two extreme performance groups, one with a high litter size (n = 61, > or = 14.3 piglets per litter) and the other with a low litter size (n = 62, < or = 11.3 piglets per litter). Although genotype and allele frequencies were uneven with 2.4% (AA), 16.3% (AB), 81.3% (BB) and 0.11 (A): 0.89 (B), the allele A was the unfavourable one, leading to less offspring. With regard to the level of significance at p < 0.05, the total number of born (TNB) and number of born alive (NBA) piglets were associated with BF genotypes. The genotype AA led to 10.55 TNB and 10.00 NBA, whereas the genotype BB led to 13.19 TNB and 12.11 NBA. The genotype AB was intermediate. In future, a systematic mating test is necessary in order to obtain more balanced genotype frequencies. Furthermore, it should be taken into consideration that the investigated polymorphism is located in an intronic region and the causative mutation is not clear yet.

Complement component 3 (C 3) and diabetes mellitus.

Complement factor 3 (C3) phenotype and allele frequencies were defined in 312 patients with Type 1 diabetes (IDDM), 256 patients with Type 2 diabetes mellitus (NIDDM), 114 apparently healthy first-degree relatives of Type 1 diabetics, in 10 families (29 members) with a familial history of Type 1 or Type 2 diabetes, and 512 controls (blood donors). All persons investigated were Europeans. There is no evidence to suggest that genes linked to C3 influence susceptibility to Type 1 and Type 2 diabetes and to their late complications. C3 levels in blood plasma were found to be slightly elevated in both types of diabetes. But the C3 concentrations varied considerably within the groups. C3 split products were demonstrable in a high percentage in the blood plasma of freshly manifested Type 1 diabetic persons as well as in Type 1 diabetics with a duration of the disease of 1 to 3 years. C3 proteolysis could also be found in plasma of Type 2 diabetics (26%).

[Therapy of obesity--effectiveness of calorie-reducing diets with various basic nutritional relations]. / Zur Therapie der Fettsucht--Effektivität kalorienreduzierter Diäten mit unterschiedlichen Grundnährstoffrelationen.

Within the research project nutrition and performance on altogether 80 test persons during a three weeks' test period the problem was examined, whether the relations of the basal nutrients have an influence on the effectiveness of a diet with an only moderate reduction of calories. The relations of the nutrients were tested in four variants. The daily caloric intake orients at the optimum weight of the test person: 30 kcal/kg optimum weight a day. It was shown that the so-called optimum weight caloric diet led to a sufficient continuous decrease of weight without disturbances of the general state of health. The variation of the relations of the basal nutrients had no decisive influence on the effectiveness.