Validation of biomarkers for loin meat quality (M. longissimus) of pigs.

The aim of this study was to validate previously reported associations between microarray gene expression levels and pork quality traits using real-time PCR. Meat samples and meat quality data from 100 pigs were collected from a different pig breed to the one tested by microarray (Large White versus Pietrain) and a different country of origin (Denmark versus Germany). Ten genes (CARP, MB, CSRP3, TNNC1, VAPB, TNNI1, HSPB1, TNNT1, TIMP-1, RAD-like) were chosen from the original microarray study on the basis of the association between gene expression levels and the meat quality traits meat %, back fat, pH24, drip loss %, colour a*, colour b*, colour L*, WB-SF, SFA, MUFA, PUFA. Real-time PCR detection methods were developed for validation of all ten genes, confirming association with drip loss (two of two genes), ultimate pH (three of four genes), a* (redness) (two of six genes) and L*(lightness) (two of four genes). Furthermore, several new correlations for MUFA and PUFA were established due to additional meat quality trait information on fatty acid composition not available for the microarray study. Regression studies showed that the maximum explanation of the phenotypic variance of the meat quality traits was 50% for the ultimate pH trait using these ten genes only. Additional studies showed that the gene expression of several of the genes was correlated with each other. We conclude that the genes initially selected from the microarray study were robust, explaining variances of the genes for the meat quality traits.

Sex-related differences of morphometric, densitometric, and geometric parameters of tibia and tarsometatarsal bone in 14-month-old ostriches (Struthio camelus).

The aim of the current study was to investigate basic morphometric, geometric, and densitometric parameters of tibia and tarsometatarsus in 14-mo-old male and female ostriches, and interrelationships between these parameters. The study was conducted on 20 tibiae and 20 tarsometatarsal bones of the left pelvic limb derived from 20 healthy 14-mo-old ostriches (Struthio camelus): 10 males and 10 females. The following parameters were determined using peripheral quantitative computed tomography: bone mineral content (BMC), volumetric bone mineral density (vBMD), cortical content (CRT_CNT), cortical density (CRT_DEN), trabecular content, trabecular density (TRAB_DEN), bone area (TOT_A), trabecular area (TRAB_A), cortical area (CRT_A), cortical thickness (CRT_THK_C), periosteal circumference (PERI_C), endocortical circumference (ENDO_C), and strength-strain index (SSI) in the metaphysis and diaphysis of the bones. Statistical evaluation of the obtained results was performed using Student's t-test, and the Pearson correlation coefficient between the investigated parameters was determined. The obtained results have shown significant differences in proximal metaphysis between males and females when evaluating such parameters as CRT_DEN, TOT_A, TRAB_A, PERI_C, SSI in tibia (P < 0.05), and BMC, vBMD, TRAB_DEN, CRT_CNT, TOT_A, TRAB_A, cortical area, PERI_C, ENDO_C, SSI in tarsometatarsus (P < 0.05). Significant differences between the 2 sexes were found in all the investigated parameters of diaphysis of tibia, except for CRT_DEN and ENDO_C (P < 0.05). Significant positive correlations between BW and bone weight were found (P < 0.05). Furthermore, numerous correlations of morphometric, geometric, and densitometric parameters of metaphysis and diaphysis of the tibia and tarsometatarsus were stated (P < 0.05). In conclusion, the present investigation demonstrated sex-related differences in morphometric, densitometric, and geometric properties of tibia and tarsometatarsus in 14-mo-old ostriches. Numerous correleations observed between the investigated parameters have shown that ostrich tibia and tarsometatarsus may present a valuable model for further studies on bone tissue metabolism regulation in breeding birds.

A search for genetic markers associated with egg production in the ostrich (Struthio camelus).

The aim of the current study was to search for genetic markers, microsatellite loci associated with laying performance in ostriches. The material consisted of two groups of ostrich hens characterized by high or low laying performance (over 75 and less than 25 eggs per season, respectively). The investigation covered 30 microsatellite loci characteristic for the ostrich (the CAU group) and led to identification of significant differences in allele and genotype frequencies between the two groups of hens considered. Out of a total of 30 microsatellite loci examined, 28 showed different alleles in relation to analyzed performance groups. In hens of high laying performance (HP group, n = 12), specific alleles occurred in 23 microsatellite loci (40 alleles of 243 identified), while in those of low egg production (LP group, n = 12), they occurred in 22 (51 alleles of 243 identified). The results indicate the usefulness of the microsatellite loci as the potential genetic markers associated with laying performance that can be applied for genetic improvement of ostrich flocks.

Study of bovine gene: the temporal-spatial expression patterns, polymorphism and association analysis with meat production traits.

The gene () encodes a transcription factor belonging to the MEF2 family that plays an important role in myogenesis by transcriptional regulation of genes involved in skeletal muscle growth and development. Despite the established importance of the factors in the muscular growth and development, the temporal-spatial expression and biological function of have not been reported in cattle. The aim of this study was to analyze the level of expression in the developing longissimus dorsi muscle (LM) of 4 cattle breeds (Polish Holstein-Friesian [HF], Limousine [LIM], Hereford [HER], Polish Red [PR]), differing in terms of meat production and utility type, at 6, 9, and 12 mo of age. The genetic polymorphism and expression patterns in 6 tissues (heart, spleen, liver, semitendinosus muscle [ST], gluteus medius muscle [GM], and LM) were also investigated. The results showed that mRNA was expressed at a high level in adult skeletal and cardiac muscles. Moreover, expression was markedly greater in the GM than in the LM ( 0.05) and ST ( 0.01). An age-dependent and breed-specific comparison of mRNA level in skeletal muscle of HF, LIM, HER, and PR bulls showed that age was significant differentiating factor of transcript/protein abundance in the LM of HER and LIM ( 0.001) compared to HF and PR, for which the differences in mRNA level were not significant ( > 0.05). Regarding the breed effect on the expression, significantly greater mRNA/protein level was noticed in the LM of 9 and 12 mo-old HER than of LIM ( 0.01), HF ( 0.001), and PR ( 0.001). Four novel SNP, namely, (promoter), (exon 7), (exon 8), and (3'UTR), were identified. We found that 3'UTR variant, situated within the seed region of the miR-5187-3p and miR-6931-5p binding sites, was associated with the level of mRNA/protein in LM of 12-mo-old HF bulls. In addition, we observed a significant association between some carcass quality traits, including meat and carcass fatness quality traits, and various 3'UTR genotypes in the investigated population of HF cattle. Our finding provides new evidence of the significant role in the postnatal muscle growth and development in cattle, and indicates that can be a promising molecular marker for carcass quality-related traits in adult cattle.

Association of POU1F1/RsaI genotypes with carcass traits in pigs.

The objective of this study was to evaluate an association between the polymorphism of the porcine pituitary-specific transcription factor gene (POU1F1, previously called PIT1) and carcass quality in F2 animals (grandparents: Zlotnicka Spotted boars and Polish Large White sows) being a part of experimental material prepared for a QTL mapping project. The analysis covered a total of 188 F2 offspring of 13 males and 67 females (F1 generation). The RsaI PCR/RFLP polymorphism of the POU1F1 gene was identified and the least squares method was used to evaluate the significance of its effect on the value of carcass quality traits. Three POU1F1/RsaI genotypes were identified in F2 porkers: EE (n=32), EF (n=68) and FF (n=88). Twenty-four carcass quality traits were measured after 24 h of cooling. The POU1F1/RsaI genotype proved to have a significant effect on the following traits: weight of ham bone and bacon including ribs, fat thickness at the lower back (point K3), over the loin, and average fat thickness (mean of five measurements). These results confirm that the POU1F1 gene may be linked to the gene/genes affecting fat deposition in the pig carcass. Moreover, pigs with the EE genotype had a greater loin eye area and showed a higher meat weight and content of carcass than animals of both EF and FF genotypes (unsignificant association), which suggests that a further study is necessary to confirm or exclude the effect of the POU1F1 gene on these traits.

The expression of genes PKM2 and CAST in the muscle tissue of pigs differentiated by glycolytic potential and drip loss, with reference to the genetic group.

The present studies aimed at an analysis of the expression level of genes PKM2 and CAST in Longissimus lumborum [LL] muscle tissue of pigs differing as regards the glycolytic potential [GP] and drip loss [DL] from the LL muscle, with reference to the genetic group. The studies covered a total of 65 pigs: 20 purebred Landrace [L], 22 crossbreeds of Landrace with the Yorkshire [L x Y] and 23 three-breed crosses (Landrace x Yorkshire) x Duroc [(L x Y) x D]. In the case of gene PKM2 one may observe in (L x Y) x D crossbreds, compared to L x Y crossbreds, an increased expression, closely related with the increase in dry matter content, including intramuscular fat, as well as a more favourable progress of glycolytic and energy metabolism during the early time post mortem (pH(45) and R(1)). Compared with Landrace animals, the lower expression of the CAST gene observed in (L x Y) x D pigs is manifested by a marked improvement of meat quality (R(1) pH(45) pH(24), pH(48)), arising from the rate of glycolytic and energy metabolism, typical for normal meat, that in effect results in its higher culinary and technological value.