To investigate the effect of different dietary energy and protein levels on meat performance and meat quality of Jinghai yellow chickens, 480 43-day old Jinghai yellow chickens with similar weight were randomly divide...To investigate the effect of different dietary energy and protein levels on meat performance and meat quality of Jinghai yellow chickens, 480 43-day old Jinghai yellow chickens with similar weight were randomly divided into four experimental groups: experimental group 1 (protein 15%, metabolic energy 9.95 MJ/kg), experimental group 2 (protein 16%, metabolic energy 10.95 MJ/kg), experimental group 3 (protein 17%, metabolic energy 12.65 MJ/kg) and experimental group 4 ( protein 18%, metabolic energy 13.95 MJ/kg), respectively. All chickens were slaughtered at 112-day old. The breast and leg muscles of Jinghai yellow chickens were collected, to determine the slaughter performance, conventional meat quality and muscle chemical indicators. The results indicated that dressing-out percentage and eviscerated yield percentage in four experimental groups were above 87.27% and 67.00%, respectively; other slaughter performance indicators exhibited no significant differences among various groups (P 〉 0.05 ) ; breast muscle color of hens in experimental group 4 varied significantly from that in other three groups ( P 〈 0.05 ) ; leg muscle color of hens in experimental group 2 varied extremely significantly from that in other three groups ( P 〈 0.01 ) ; water-holding capacity of breast muscles of hens in experimental group 3 was significantly higher than that in experimental group 4 (P 〈 0.05 ) ; thiamine content of breast muscles of cocks in experimental group 3 was significandy higher than that in experimental group 2 ( P 〈 0.05 ) ; however, other properties exhibited no significant differenees among various groups (P 〉 0.05 ).展开更多
The main objective of this work is to investigate the effect of windage heating on the micro high-speed rotor-stator cavity.The influences of centrifugal force and spacing on the windage heating are analyzed with and ...The main objective of this work is to investigate the effect of windage heating on the micro high-speed rotor-stator cavity.The influences of centrifugal force and spacing on the windage heating are analyzed with and without the change of gap ratio respectively.The results demonstrate that there is no difference in the flow structure between micro and large-scale rotorstator cavities at the same rotational Reynolds number and gap ratio.However,the windage heating induced by the larger centrifugal force and smaller spacing brings the different heat transfer laws for the micro rotor-stator cavity.The larger centrifugal force weakens the local heat transfer near the rotor periphery.Such influence can be strengthened at higher rotational Reynolds numbers and lower rotor excess temperatures.Besides,the smaller spacing further enhances the windage heating and reduces the average heat transfer especially under the condition of lower gap ratio.The findings of this work contribute to the design of rotor-stator cavity utilized in the micro rotating machinery.展开更多
基金Supported by Special Fund for National Broiler Industry Technology System ofChina(CARS-42-G23)Project of Priority Academic Program Development ofJiangsu Higher Education Institutionsthe New Century Talent Project of Yangzhou University
文摘To investigate the effect of different dietary energy and protein levels on meat performance and meat quality of Jinghai yellow chickens, 480 43-day old Jinghai yellow chickens with similar weight were randomly divided into four experimental groups: experimental group 1 (protein 15%, metabolic energy 9.95 MJ/kg), experimental group 2 (protein 16%, metabolic energy 10.95 MJ/kg), experimental group 3 (protein 17%, metabolic energy 12.65 MJ/kg) and experimental group 4 ( protein 18%, metabolic energy 13.95 MJ/kg), respectively. All chickens were slaughtered at 112-day old. The breast and leg muscles of Jinghai yellow chickens were collected, to determine the slaughter performance, conventional meat quality and muscle chemical indicators. The results indicated that dressing-out percentage and eviscerated yield percentage in four experimental groups were above 87.27% and 67.00%, respectively; other slaughter performance indicators exhibited no significant differences among various groups (P 〉 0.05 ) ; breast muscle color of hens in experimental group 4 varied significantly from that in other three groups ( P 〈 0.05 ) ; leg muscle color of hens in experimental group 2 varied extremely significantly from that in other three groups ( P 〈 0.01 ) ; water-holding capacity of breast muscles of hens in experimental group 3 was significantly higher than that in experimental group 4 (P 〈 0.05 ) ; thiamine content of breast muscles of cocks in experimental group 3 was significandy higher than that in experimental group 2 ( P 〈 0.05 ) ; however, other properties exhibited no significant differenees among various groups (P 〉 0.05 ).
基金support from the National Natural Science Foundation of China(Grant No.51606003)The authors acknowledge the editors for handling the manuscript and the reviewers for their constructive comments that have significantly improved the manuscript.
文摘The main objective of this work is to investigate the effect of windage heating on the micro high-speed rotor-stator cavity.The influences of centrifugal force and spacing on the windage heating are analyzed with and without the change of gap ratio respectively.The results demonstrate that there is no difference in the flow structure between micro and large-scale rotorstator cavities at the same rotational Reynolds number and gap ratio.However,the windage heating induced by the larger centrifugal force and smaller spacing brings the different heat transfer laws for the micro rotor-stator cavity.The larger centrifugal force weakens the local heat transfer near the rotor periphery.Such influence can be strengthened at higher rotational Reynolds numbers and lower rotor excess temperatures.Besides,the smaller spacing further enhances the windage heating and reduces the average heat transfer especially under the condition of lower gap ratio.The findings of this work contribute to the design of rotor-stator cavity utilized in the micro rotating machinery.