ABSTRACT
The objective of this study was to evaluate the possibility of prediction of intramuscular fat (IMF) in live pigs using ultrasound method. Moreover, the accuracy of prediction at five different ultrasound intensity levels was investigated. Cross-sectional images of longissimus dorsi muscle (LD) at right last rib area, from hybrid pigs, were taken. Each pig was scanned at the same frequency (3.5 MHz) and at the five different ultrasound intensity levels 70%, 75%, 80%, 85% and 90% of total amplifying of sonograph, using the device ALOKA SSD-500. The video image analysis was used to predict IMF content (ultrasound intramuscular fat (UIMF) 70 to UIMF90). The second day after slaughter, the dissection of right half carcass was done. A sample of LD at the last rib was taken for laboratory analysis of IMF content (LAIMF). Scatter plots with UIMF on the x-axis and LAIMF on the y-axis were constructed to account for individual variability within and between intensity levels. Correlations between LAIMF and UIMF were significantly different from zero (r = 0.40-0.52), except for correlation between LAIMF and UIMF90 (r = 0.14). Statistical model with LAIMF (the dependent variable), UIMF (the same model for each intensity level), live weight (the covariates) and sex (the fixed effect) was developed. Coefficients of determination (R2) were 0.33, 0.38, 0.34, 0.25 and 0.17 with UIMF at the intensity level 70%, 75%, 80%, 85% and 90%. Root mean square errors ranged from 0.516% to 0.639%. Standard errors of individual prediction ranged from 0.523% to 0.649%. Goodness-of-fit of the model was also justified by testing the residuals for normality. Although the results are not quite unequivocal in favour of the one intensity level, it seems that intensity levels 75% and 80% are the most suitable to predict IMF in live pigs. Further research is needed, mainly to increase accuracy of collecting, processing and evaluating the sonograms using video image analysis.
ABSTRACT
Pituitary transcription factor (PIT-1) has been shown to be a positive regulatory factor of growth hormone, prolactin, and thyrotrophin-beta-subunit (TSH-beta) in the mammalian pituitary. Therefore, the gene encoding PIT-1 (POU1F1) was chosen as a candidate gene to investigate its association with growth and carcass traits in pigs. The purpose of this study was to analyse porcine POU1F1 genetic variability in populations of Large White and Large White x landrace pigs, by using PCR-RFLP analysis and to determine its possible associations with two carcass traits (backfat and percentage of lean content). Two different POU1F1-PCR-RFLP (POU1F1/RsaI and POU1F1/MspI) tests were applied to genomic DNA isolated from porcine blood (120 pigs) and hair roots (10 pigs). The present results clearly indicated that the MspI DD genotype was the fattest compared with both other genotypes (CC, CD) in analyzed swine population. For POU1F1/RsaI polymorphism no significance differences were seen for lean-to-fat ratio.
