We investigated the effect of the estrogen receptor (ESR) gene on growth and reproductive traits in four Large White-based commercial pig lines. A total of 9,015 litter records from 4,262 sows genotyped at the ESR locus were analyzed to determine whether ESR influenced total number born (TNB) or number born alive (NBA). Teat number (TN), test ADG, ADFI, feed:gain ratio (F/G), and ultrasonic backfat (BF) were also analyzed to determine effects of ESR. The TNB and NBA were increased per favorable allele of ESR (P < .01) with additive effects of .42 (.31) and .39 (.31) pigs/litter in the first parity (later parities), respectively. Dominance effects were near zero in parity one, but they were .16 and .14 pigs for TNB and NBA, respectively, in later parities (P < .05). A favorable additive pleiotropic effect was detected for BF (P < .001; -.11 mm per copy of the favorable litter size allele). There were no detectable effects on ADG or F/G (P > .10), although ADF was reduced 18 g/d per copy of the favorable litter size allele (P < .05). Average TN was 13.1 for pigs carrying the favorable litter size allele vs 13.2 for noncarriers (P < .05). Marker-assisted selection using ESR is warranted to increase litter size in the Large White-based lines considered here and will be of considerable economic value to pork producers. KeywordsEstrogen Receptors, Reproduction, Growth, Genetic Markers, Major Genes, Pleiotropy Disciplines Agriculture | Animal Sciences | Genetics and Genomics Comments Effect of the Estrogen Receptor Locus on Reproduction and Production Traits in Four Commercial ABSTRACT:We investigated the effect of the estrogen receptor (ESR) gene on growth and reproductive traits in four Large White-based commercial pig lines. A total of 9,015 litter records from 4,262 sows genotyped at the ESR locus were analyzed to determine whether ESR influenced total number born (TNB) or number born alive (NBA). Teat number (TN), test ADG, ADFI, feed:gain ratio (F/G), and ultrasonic backfat (BF) were also analyzed to determine effects of ESR. The TNB and NBA were increased per favorable allele of ESR ( P < .01) with additive effects of .42 (.31) and .39 (.31) pigs/litter in the first parity (later parities), respectively. Dominance effects were near zero in parity one, but they were .16 and .14 pigs for TNB and NBA, respectively, in later parities ( P < .05). A favorable additive pleiotropic effect was detected for BF ( P < .001; −.11 mm per copy of the favorable litter size allele). There were no detectable effects on ADG or F/ G ( P > .10), although ADF was reduced 18 g/d per copy of the favorable litter size allele ( P < .05). Average TN was 13.1 for pigs carrying the favorable litter size allele vs 13.2 for noncarriers ( P < .05). Marker-assisted selection using ESR is warranted to increase litter size in the Large White-based lines considered here and will be of considerable economic value to pork producers.

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Several quantitative trait loci (QTL) affecting muscle glycogen content and related traits were mapped to pig chromosome 15 using a three-generation intercross between Berkshire × Yorkshire pigs. On the basis of the QTL location the PRKAG3 (protein kinase, AMP-activated, γ3-subunit) gene was considered to be a good candidate for the observed effects. Differences in the PRKAG3 gene sequences of the founder animals of the intercross were analyzed. The RN− mutation previously reported was not present in the cross but three missense substitutions and a polymorphic short interspersed element (SINE) were identified. To confirm the hypothesis that at least one of these mutations was associated with differences in meat quality, &gt;1800 animals from several unrelated commercial lines were genotyped for the candidate substitutions and an association study was performed. The results demonstrate the presence of new economically important alleles of the PRKAG3 gene affecting the glycogen content in the muscle and the resulting meat quality. Haplotype analysis was shown to resolve the effects of PRKAG3 more clearly than analysis of individual polymorphisms. Because of their prevalence in the more common commercial breeds, the potential implications for the pig industry and consumers are considerably greater than the original discovery of the RN− mutation. Furthermore, these results illustrate that additional alleles of genes involved in major mutations may play a significant role in quantitative trait variation.

The direct quantification of the concentration of viable bacterial mRNA with real-time quantitative reverse transcription polymerase chain reaction allows identification of both culture-positive bacterial infection and so-called unculturable bacterial infection in a simulated septic arthritis model. In contrast to conventional polymerase chain reaction, real-time quantitative reverse transcription polymerase chain reaction minimizes false-positive detection of nonviable bacteria and thus provides relevant information on the success or failure of antibiotic therapy.