The growth hormone / insulin-like growth factor-1 (GH/IGF-1) pathway of the somatotropic axis is the major controller for growth rate and body size in vertebrates, but the effect of selection on the expression of GH/IGF-1 somatotropic axis genes and their association with body size and growth performance in farm animals is not fully understood. We analyzed a time series of expression profiles of GH/IGF-1 somatotropic axis genes in two chicken breeds, the Daweishan mini chickens and Wuding chickens, and the commercial Avian broilers hybrid exhibiting markedly different body sizes and growth rates. We found that growth rate and feed conversion efficiency in Daweishan mini chickens were significantly lower than those in Wuding chickens and Avian broilers. The Wuding and Daweishan mini chickens showed higher levels of plasma GH, pituitary GH mRNA but lower levels of hepatic growth hormone receptor (GHR) mRNA than in Avian broilers. Daweishan mini chickens showed significantly lower levels of plasma IGF-1, thigh muscle and hepatic IGF-1 mRNA than did Avian broilers and Wuding chickens. These results suggest that the GH part of the somatotropic axis is the main regulator of growth rate, while IGF-1 may regulate both growth rate and body weight. Selection for growth performance and body size have altered the expression profiles of somatotropic axis genes in a breed-, age-, and tissue-specific manner, and manner, and alteration of regulatory mechanisms of these genes might play an important role in the developmental characteristics of chickens.
Hydrate-based gas separation is one of the potential methods of carbon dioxide capture from fuel gases (CO 2 /H 2 ) for an integrated coal gasification combined cycle (IGCC) power plant. In this study, the influences of selected factors, including porous properties, tetrahydrofuran (THF) concentration, sodium dodecyl sulfate (SDS) concentration, and initial pressure, of the operation system on hydrate phase equilibria, gas consumption, and gas separation are experimentally investigated by a designed orthogonal test method. It is found that the porous property is the most important factor on hydrate phase equilibria and CO 2 gas separation, where the gas separation becomes better in silica gel. The presence of THF moderates the hydrate phase equilibrium and improves the gas consumption and CO 2 gas recovery, and 3 mol % THF should be a suitable value for gas separation. The initial pressure has an important effect on the hydrate equilibrium pressure. With the increase of the driving force, the gas consumption increases, while the gas separation effect becomes worse.
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