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Luo J.,Sichuan Agricultural University | Lei H.,Sichuan Agricultural University | Lei H.,University of Alberta | Shen L.,Sichuan Agricultural University | And 8 more authors.
Asian-Australasian Journal of Animal Sciences | Year: 2015

The Liangshan pig is a traditional Chinese small-sized breed; it has a relatively long feeding period and low meat production ability but superior meat quality. This study utilized three non-linear growth models (Von Bertalanffy, Gompertz, and logistic) to fit the growth curve of Liangshan pigs from an unselected, random-bred pig population and estimate the pigs most suitable slaughter weight. The growth development data at 20 time points of 275 Liangshan pigs (from birth to 250 d) were collected. To analyze the relative gene expression related to development, seven slaughter weight phases (50, 58, 66, 74, 82, 90, and 98 kg) (20 pigs per phase) were examined. We found that the Liangshan pig growth curve fit the typical S-curve well and that their growth turning point was 193.4 days at a weight of 62.5 kg, according to the best fit Von Bertalanffy model based on the goodness of fit criteria. Furthermore, we estimated that the most suitable slaughter weight was 62.5 to 74.9 kg based on the growth curve and the relative expression levels of growth-related genes. Copyright © 2015 by Asian-Australasian Journal of Animal Sciences.

Shen L.,Sichuan Agricultural University | Luo J.,Sichuan Agricultural University | Du J.,Sichuan Agricultural University | Liu C.,Sichuan Agricultural University | And 14 more authors.
PLoS ONE | Year: 2015

Animal growth curves can provide essential information for animal breeders to optimize feeding and management strategies. However, the genetic mechanism underlying the phenotypic differentiation between the inflection point and asymptotic stages of the growth curve is not well characterized. Here, we employed Liangshan pigs in stages of growth at the inflection point (under inflection point: UIP) and the two asymptotic stages (before the inflection point: BIP, after the inflection point: AIP) as models to survey global gene expression in the longissimus dorsi muscle using digital gene expression (DGE) tag profiling. We found Liangshan pigs reached maximum growth rate (UIP) at 163.6 days of age and a weight of 134.6 kg. The DGE libraries generated 117 million reads of 5.89 gigabases in length. 21,331,20,996 and 20,139 expressed transcripts were identified BIP, UIP and AIP, respectively. Among them, we identified 757 differentially expressed genes (DEGs) between BIP and UIP, and 271 DEGs between AIP and UIP. An enrichment analysis of DEGs proved the immune system was strengthened in the AIP stage. Energy metabolism rate, global transcriptional activity and bone development intensity were highest UIP. Meat from Liangshan pigs had the highest intramuscular fat content and most favorable fatty acid composition in the AIP. Three hundred eighty (27.70%) specific expression genes were highly enriched in QTL regions for growth and meat quality traits. This study completed a comprehensive analysis of diverse genetic mechanisms underlying the inflection point and asymptotic stages of growth. Our findings will serve as an important resource in the understanding of animal growth and development in indigenous pig breeds. Copyright: © 2015 Shen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Lei H.G.,Sichuan Agricultural University | Shen L.Y.,Sichuan Agricultural University | Zhang S.H.,Sichuan Agricultural University | Wu Z.H.,Sichuan Agricultural University | And 7 more authors.
Animal Production Science | Year: 2015

Post-mortem muscle energy metabolism plays an important role in pork quality. To analyse the differences of meat quality and energy metabolism, three commercial pig crossbreeds frequently used in China were studied, they were DT (Duroc × Taihu; n ≤ 16), PIC (five-way crossbreed from Pig Improvement Co., UK; n ≤ 29) and DLY (Duroc × (Landrace × Yorkshire); n ≤ 19) pigs. The results showed that DT pigs had a higher post-mortem pH45 min and pH24 h, lower shear force and drip loss, higher muscle free-glucose and glycogen contents, and lower lactic acid content than did PIC and DLY pigs. Post-mortem muscle free-glucose content of these three pig crossbreeds changed little, from 45 min to 96 h post-mortem. The expression levels of PRKAG3 (encoding a regulatory subunit of the AMP-activated protein kinase) and GYS1 (encoding muscle glycogen synthase) genes of DT pigs were significantly lower than those of PIC and DLY pigs. DT pigs had a higher expression level of glycogenin-1-like (encoding glycogenin) gene than did PIC and DLY pigs. In conclusion, DT pigs had better meat quality than did the other two pig crossbreeds. We deduced that the post-mortem muscle energy status and metabolism of DT pigs might be an important reason for their good meat quality, and future research should focus on the molecular and physiological mechanism of post-mortem muscle energy metabolism to find ways to improve meat quality. © 2015 CSIRO.

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