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Porcine chromosome 4 harbours many quantitative trait loci (QTL) affecting meat quality, fatness and carcass composition traits, detected in resource pig populations previously. However, prior to selection in commercial breeds, QTL identified in an intercross between divergent breeds require confirmation, so that they can be segregated. Consequently, the objective of this study was to validate several QTL on porcine chromosome 4 responsible for meat and carcass quality traits. The experimental population consisted of 14 crossbred paternal half-sib families. The region of investigation was the q arm of SSC4 flanked by the markers S0073 and S0813. Regression analysis resulted in the validation of three QTL within the interval: Minolta a* loin, back fat thickness and the weight of trimmed ham. The results were additionally confirmed by factor analysis. Candidate genes were proposed for meat colour, which was the most evident QTL validated in this study. [ABSTRACT FROM AUTHOR]

In a previous study, QTL for carcass composition and meat quality were identified in a commercial finisher cross. The main objective of the current study was to confirm and fine map the QTL on SSC4 and SSC11 by genotyping an increased number of individuals and markers and to analyze the data using a combined linkage and linkage disequilibrium analysis method. A modified version of the method excludes linkage disequilibrium information from the analysis, enabling the comparison of results based on linkage information only or results based on combined linkage and linkage disequilibrium information. Nine additional paternal half-sib families were genotyped for 18 markers, resulting in a total of 1,855 animals genotyped for 15 and 13 markers on SSC4 and SSC11, respectively. The QTL affecting meat color on SSC4 was confirmed, whereas the QTL affecting LM weight could not be confirmed. The combined linkage and linkage disequilibrium analysis resulted in the identification of new significant effects for 14 traits on the 2 chromosomes. Heritabilities of the QTL effects ranged from 1.8 to 13.2%. The analysis contributed to a more accurate positioning of QTL and further characterized their phenotypic effect. However, results showed that even greater marker densities are required to take full advantage of linkage disequilibrium information and to identify haplotypes associated with favorable QTL alleles. [ABSTRACT FROM AUTHOR]

A QTL study for carcass composition and meat quality traits was conducted on finisher pigs of a cross between a synthetic Piétrain/Large White boar line and a commercial sow cross. The mapping population comprised 715 individuals evaluated for a total of 30 traits related to growth and fatness (4 traits), carcass composition (11 traits), and meat quality (15 traits). Offspring of 8 sires (n = 715) were used for linkage analysis and genotyped for 73 microsatellite markers covering 14 chromosomal regions representing approximately 50% of the pig genome. The regions examined were selected based on previous studies suggesting the presence of QTL affecting carcass composition or meat quality traits. Thirty-two QTL exceeding the 5% chromosome-wise significance level were identified. Among these, 5 QTL affecting 5 different traits were significant at the 1% chromosome-wise level. The greatest significance levels were found for a QTL affecting loin weight on SSC11 and a QTL with an effect on the Japanese color scale score of the loin on SSC4. About one-third of the identified QTL were in agreement with QTL previously reported. Results showed that QTL affecting carcass composition and meat quality traits segregated within commercial lines. Use of these results for marker-assisted selection offers opportunities for improving pork quality by within-line selection. [ABSTRACT FROM AUTHOR]

Marker density of a QTL region on pig chromosome 4 was increased. New microsatellites were identified by in silico mining of BAC-end and genomic shotgun sequences. Among 8,784 BAC-end sequences predicted within the region, 148 microsatellites were identified. In addition, 27,450 CA/TG repeats were identified within the genomic shotgun sequences, of which 157 were most likely located on SSC4q. A selection of 61 new microsatellites was mapped, together with previously mapped markers. The results showed that the human-pig comparative map in combination with BAC-end and genomic sequence resources provides an excellent source for a highly efficient and targeted development of markers.

Breeding goals in pigs are subject to change and are directed much more toward retail carcass yield and meat quality because of the high economic value of these traits. The objective of this study was to estimate genetic parameters of growth, carcass, and meat quality traits. Carcass components included ham and loin weights as primal cuts, which were further dissected into boneless subprimal cuts. Meat quality traits included pH, drip loss, purge, firmness, and color and marbling of both ham and loin. Phenotypic measurements were collected on a commercial crossbred pig population (n = 1,855). Genetic parameters were estimated using REML procedures applied to a bivariate animal model. Heritability estimates for carcass traits varied from 0.29 to 0.51, with 0.39 and 0.51 for the boneless subprimals of ham and loin, respectively. Heritability estimates for meat quality traits ranged from 0.08 to 0.28, with low estimates for the water holding capacity traits and higher values for the color traits: Minolta b*(0.14), L* (0.15), a* (0.24), and Japanese color scale (0.25). Heritability estimates differed for marbling of ham (0.14) and loin (0.31). Neither backfat nor ADG was correlated with loin depth (r(g) = 0.0), and their mutual genetic correlation was 0.27. Loin primal was moderately correlated with ham primal (r(g) = 0.31) and more strongly correlated with boneless ham (r(g) = 0.58). Backfat was negatively correlated with (sub)primal cut values. Average daily gain was unfavorably correlated with subprimals and with most meat quality characteristics measured. Genetic correlations among the color measurements and water-holding capacity traits were high (average r(g) = 0.70), except for Minolta a* (average r(g) = 0.17). The estimated genetic parameters indicate that meat quality and valuable cut yields can be improved by genetic selection. The estimated genetic parameters make it possible to predict the response to selection on performance, carcass, and meat quality traits and to design an effective breeding strategy fitting pricing systems based on retail carcass and quality characteristics.

1. A method of continuous infusion in the unrestrained rat is described, which provides a scientifically acceptable and easily maintained rodent model for use in toxicological investigations. 2. Sprague Dawley SPF rats had cannulas implanted into the vena cava via the femoral vein, and were continuously infused with physiological saline for a total of 28 or 90 days. 3. The results indicate that there was no change in body weight, food consumption, clinical observations or clinical biochemistry of infused rats when compared to non-infused rats. There were small changes in haematological parameters, however none were toxicologically significant. Urinary volume was increased and urinary specific gravity and osmolality were decreased. At macroscopic and microscopic examination there were findings of scar formation associated with the area of surgery and minimal irritation in the area of the vena cava which accommodated the cannula. 4. These results indicate that implantation of a cannula into the vena cava of a rat and subsequent continuous intravenous infusion of physiological saline produces no toxicological adverse effects over a period of 90 days. Consequently, this model can be recommended for the continuous intravenous administration of test substances to rats.

To investigate the value of the plain abdominal radiograph in the assessment of constipation we prospectively studied 30 patients (20 females, 10 males, mean age 48.6 years, range 21-76 years). These patients underwent the following tests: plain abdominal radiograph in supine position, measurement of stool weight (mean of 5 days) and whole gut transit time (20 radioopaque pellets, fluoroscopy of stools). All patients completed a questionnaire regarding their defaecation characteristics (a.o. average defaecation frequency and faecal consistency). The abdominal films were coded and independently scored for the degree of faecal stasis in ascending, transverse, descending colon and rectosigmoid by four gastroenterologists. To each of these parts of the colon a score of 1 (no faeces) to 4 (loaded with faeces) was assigned. The film scores given by the four observers were significantly correlated (p less than 0.001). Significant correlations were found between the radiograph scores and frequency of defaecation, faecal consistency and stool weight. The strength of these correlations were of the same order of magnitude as those between the other subjective and objective defaecation variables. The scores for the left colon (descending colon and rectosigmoid) showed a better correlation with the other defaecation parameters than the scores for the right colon. It is concluded that in the assessment of constipation a simple plain abdominal radiograph is as reliable as measurement of faecal weight or marker transit and can thus be advocated as the first procedure. When an abdominal radiograph is used for this purpose the stasis in the descending and sigmoid colon provides most information.

Acute cholestasis is a rare complication of EPP with a high mortality rate despite extensive treatment with corticosteroids, cholestyramine, and antioxidants. A single survivor, reported in the literature, was treated with blood exchange transfusions. We treated two EPP patients with blood exchange and additional blood transfusions which resulted in full clinical and biochemical recovery from the cholestasis and accompanying hepatitis. Recurrences of the cholestasis and hepatitis could repeatedly be corrected by additional blood transfusions.