This study was conducted to evaluate the effects of feed form(mash and crumble-pellet) and feed particle size(fine, medium and coarse) on growth performance, carcass characteristics and digestive tract development of ...This study was conducted to evaluate the effects of feed form(mash and crumble-pellet) and feed particle size(fine, medium and coarse) on growth performance, carcass characteristics and digestive tract development of broilers. A total of 1,152 one day-old Ross 308 mixed-sex broilers were used in a factorial arrangement(2×3) based on a completely randomized design with six replicates of 32 birds each.Higher average daily gain(ADG) and average daily feed intake(ADFI) were observed(P < 0.01) for birds fed the crumble-pellet diets(CPD) than for those fed the mash diets(MD) during starter, grower and the entire experiment period. From d 1 to 40, birds fed CPD had a higher(P < 0.01) body weight(BW) than those fed MD. Birds fed CPD had a lower(P < 0.01) feed:gain ratio(F:G) during the starter phase than those fed MD. Medium or coarse particle size increased(P < 0.01) ADG and ADFI during the starter phase, but birds fed fine particle size diets had lower(P < 0.01) F:G during the grower phase. In MD,medium and coarse particle sizes resulted in higher(P < 0.05) BW, ADG and ADFI than fine particle size during the whole experiment. In CPD, particle size had no significant effect on growth performance, as indicated by a feed form × particle size interaction(P < 0.05). At 41 days of age, ten birds per treatment were randomly selected and killed for slaughter yields and digestive tract characteristics determination.It was shown that particle size and feed form alone had no significant effect on slaughter yields, so changes was the feed form × particle size interaction. The relative empty weight of the gizzard was greater(P < 0.01) and the relative length of the ileum was longer(P < 0.05) in birds fed MD than in those fed CPD. Overall, CPD improved growth performance during the entire period of the study with effects being less evident during the finisher phase than during the starter and grower phases, and the effect of feed particle size varied depending on feed form.展开更多
Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on b...Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare,meat and litter quality,N utilization,and NH3 concentrations at litter level.A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6 replicates,which was fed diets in both pellet and mash forms with different CP levels of 205.0 g/kg(H,high),187.5 g/kg(M,intermediate)and 175.0 g/kg(L,low)in the grower phase and 195.0 g/kg(H),180.0 g/kg(M)and 165.6 g/kg(L)in the finisher phase.Individual amino acids(AA)were supplemented to maintain digestible AA-to-digestible lysine ratios.Decreasing dietary CP content to 187.5 g/kg in the grower phase and 180.0 g/kg in the finisher phase reduced NH3 concentrations at litter level(P<0.001),but a further reduction in dietary CP had no additional effect.Mash treatments had better litter qualities and lower incidences of foot and hock lesions than pellet treatments at d 38(P<0.001).In addition,treatments with reduced CP had lower incidence of foot lesions at d 38(P<0.001).Broilers fed pelleted diets had higher ADFI,ADG,and final BW,improved feed conversion ratio(FCR),and heavier carcasses(P<0.001)than those fed mash diets over a production period of 39 d.Performance could not be maintained when birds were fed L CP pelleted diets.This study demonstrated that,with the supplementation of AA to meet requirements,the concentration of dietary CP can be reduced to 187.5 and 180.0 g/kg in the grower and finisher phases respectively,without impairing broiler performance,meat yield and quality.Mash diets were favorable when considering the overall litter quality and welfare of the birds.However,they could not maintain the same broiler performance and slaughter yield as pelleted diets.Results from the present study may assist the poultry sector towards a socially acceptable lowemission farming system.展开更多
The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In o...The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.展开更多
文摘This study was conducted to evaluate the effects of feed form(mash and crumble-pellet) and feed particle size(fine, medium and coarse) on growth performance, carcass characteristics and digestive tract development of broilers. A total of 1,152 one day-old Ross 308 mixed-sex broilers were used in a factorial arrangement(2×3) based on a completely randomized design with six replicates of 32 birds each.Higher average daily gain(ADG) and average daily feed intake(ADFI) were observed(P < 0.01) for birds fed the crumble-pellet diets(CPD) than for those fed the mash diets(MD) during starter, grower and the entire experiment period. From d 1 to 40, birds fed CPD had a higher(P < 0.01) body weight(BW) than those fed MD. Birds fed CPD had a lower(P < 0.01) feed:gain ratio(F:G) during the starter phase than those fed MD. Medium or coarse particle size increased(P < 0.01) ADG and ADFI during the starter phase, but birds fed fine particle size diets had lower(P < 0.01) F:G during the grower phase. In MD,medium and coarse particle sizes resulted in higher(P < 0.05) BW, ADG and ADFI than fine particle size during the whole experiment. In CPD, particle size had no significant effect on growth performance, as indicated by a feed form × particle size interaction(P < 0.05). At 41 days of age, ten birds per treatment were randomly selected and killed for slaughter yields and digestive tract characteristics determination.It was shown that particle size and feed form alone had no significant effect on slaughter yields, so changes was the feed form × particle size interaction. The relative empty weight of the gizzard was greater(P < 0.01) and the relative length of the ileum was longer(P < 0.05) in birds fed MD than in those fed CPD. Overall, CPD improved growth performance during the entire period of the study with effects being less evident during the finisher phase than during the starter and grower phases, and the effect of feed particle size varied depending on feed form.
基金This study wasfinancially supported by Flanders Innovation and Entrepreneurship(VLAIO)(project number 160778)and ILVO.
文摘Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare,meat and litter quality,N utilization,and NH3 concentrations at litter level.A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6 replicates,which was fed diets in both pellet and mash forms with different CP levels of 205.0 g/kg(H,high),187.5 g/kg(M,intermediate)and 175.0 g/kg(L,low)in the grower phase and 195.0 g/kg(H),180.0 g/kg(M)and 165.6 g/kg(L)in the finisher phase.Individual amino acids(AA)were supplemented to maintain digestible AA-to-digestible lysine ratios.Decreasing dietary CP content to 187.5 g/kg in the grower phase and 180.0 g/kg in the finisher phase reduced NH3 concentrations at litter level(P<0.001),but a further reduction in dietary CP had no additional effect.Mash treatments had better litter qualities and lower incidences of foot and hock lesions than pellet treatments at d 38(P<0.001).In addition,treatments with reduced CP had lower incidence of foot lesions at d 38(P<0.001).Broilers fed pelleted diets had higher ADFI,ADG,and final BW,improved feed conversion ratio(FCR),and heavier carcasses(P<0.001)than those fed mash diets over a production period of 39 d.Performance could not be maintained when birds were fed L CP pelleted diets.This study demonstrated that,with the supplementation of AA to meet requirements,the concentration of dietary CP can be reduced to 187.5 and 180.0 g/kg in the grower and finisher phases respectively,without impairing broiler performance,meat yield and quality.Mash diets were favorable when considering the overall litter quality and welfare of the birds.However,they could not maintain the same broiler performance and slaughter yield as pelleted diets.Results from the present study may assist the poultry sector towards a socially acceptable lowemission farming system.
基金Supported by National Natural Science Foundation of China(Grant No.51335009)Major National Science and Technology Project of China(Grant No.2011ZX04001-011)
文摘The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.
