Biological mechanisms discriminating growth rate and adult body weight phenotypes in two Chinese indigenous chicken breeds

Abstract

BackgroundIntensive selection has resulted in increased growth rates and muscularity in broiler chickens, in addition to adverse effects, including delayed organ development, sudden death syndrome, and altered metabolic rates. The biological mechanisms underlying selection responses remain largely unknown. Non-artificially-selected indigenous Chinese chicken breeds display a wide variety of phenotypes, including differential growth rate, body weight, and muscularity. The Wuding chicken breed is a fast growing large chicken breed, and the Daweishan mini chicken breed is a slow growing small chicken breed. Together they form an ideal model system to study the biological mechanisms underlying broiler chicken selection responses in a natural system. The objective of this study was to study the biological mechanisms underlying differential phenotypes between the two breeds in muscle and liver tissues, and relate these to the growth rate and body development phenotypes of the two breeds.ResultsThe muscle tissue in the Wuding breed showed higher expression of muscle development genes than muscle tissue in the Daweishan chicken breed. This expression was accompanied by higher expression of acute inflammatory response genes in Wuding chicken than in Daweishan chicken. The muscle tissue of the Daweishan mini chicken breed showed higher expression of genes involved in several metabolic mechanisms including endoplasmic reticulum, protein and lipid metabolism, energy metabolism, as well as specific immune traits than in the Wuding chicken. The liver tissue showed fewer differences between the two breeds. Genes displaying higher expression in the Wuding breed than in the Daweishan breed were not associated with a specific gene network or biological mechanism. Genes highly expressed in the Daweishan mini chicken breed compared to the Wuding breed were enriched for protein metabolism, ABC receptors, signal transduction, and IL6-related mechanisms.ConclusionsWe conclude that faster growth rates and larger body size are related to increased expression of genes involved in muscle development and immune response in muscle, while slower growth rates and smaller body size are related to increased general cellular metabolism. The liver of the Daweishan breed displayed increased expression of metabolic genes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3845-9) contains supplementary material, which is available to authorized users.

Selection for growth rate and body size have altered the expression profiles of somatotropic axis genes in chickens

“…Primers were commercially synthesized (Shanghai Shenggong Biochemistry Company P. R. China). Tissue homogenization, RNA isolation, and RT-qPCR were performed as previously described [ 27 , 28 ].…”

Silage and haylage as forage in slow and fast-growing broilers – effects on performance in Campylobacter jejuni infected birds

“…Intensive selection in fast-growing broilers has resulted in increased muscularity and growth with additional adverse effects, including delayed development of the internal organs, which may be the potential cause of several metabolic disorders such as ascites or sudden death syndrome (Dou et al 2017). The birds in the current studies did not show any signs of these metabolic disorders, although the differences in internal organ size were detected.…”

Profiles of expression pattern and tissue distribution of host defense peptides genes in different chicken (Gallus gallus) breeds related to body weight

“…We previously reported that the Daweishan mini chicken breed showed higher indexes of immune organs, especially for index of bursa, and higher expression of genes involved in specific immune traits in muscle tissue than the Wuding chickens [27]. The aim of the present investigation was to investigate the effect of body weight and age on the profiles of expression pattern of HDP genes in different immune organs and their association with innate immune function or adaptive immunity in chickens.…”

“…Tissue homogenization, RNA isolation, and RT-qPCR were performed as well as mRNA expression normalization as previously described[27,31,32]. Primer sequences for the target genes and their annealing temperatures.…”