A self-developed forced convection rheoforming （FCR） machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at differe...A self-developed forced convection rheoforming （FCR） machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at different stirring speeds prepared by the FCR process were analyzed. The experimental results suggest that with the increase of the stirring speed, the mean grain size of the semisolid decreases and the shape factor as well as the number of primary grains increase. Meanwhile, the preparation process of semisolid slurry was numerically simulated. The flow characteristics of the melt in the device and the effect of the stirring speed on temperature field and solid fraction of the melt were investigated. The simulated results show that during the preparation process of semisolid slurry, there is a complex convection within the FCR device that obviously changes the temperature field distribution and solid fraction of the melt. When the convection intensity increases, the scope of the undercooling gradient of the melt is reduced and temperature distribution is improved.展开更多
This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of ...This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of soybean in Zimbabwe due to droughts, inadequate irrigation infrastructure, high input costs, and price controls, the authors identified an alternative to soybean meal in cowpea meal due to its availability and similar amino acid profile to soybean meal. The experiment was carried out at Cold Storage Company in Kadoma. A total of 150 unsexed day-old broiler chicks (Cobb 500) were used. All the birds were brooded in one pen during the first two weeks of age and fed with standard broiler starter mash from National Foods PVT LTD for adaptation. The birds were randomly allocated into five equal groups, each with three replicates and 10 birds per replicate at three weeks of age. Five experimental diets: T1 (100% soybean meal + 0% cowpeas meal), T2 (75% soybean meal + 25% cowpeas meal), T3 (50% soybean meal + 50% cowpeas meal), T4 (25% soybean meal + 75% cowpeas meal) and T5 (0% soybean meal + 100% cowpeas meal) were formulated to be iso-caloric and iso-nitrogenous to meet nutrient requirements of broilers according to NRC (2001). Ration formulation using maize, soybean and cowpea meal as ingredients for broiler starter (21% Crude Protein) and broiler finisher (19% Crude Protein) was done using the Pearson Square Method. Feed intake (g) and weight gain (g) were recorded weekly. Feed Conversion Ratio (FCR) and bioeconomic efficiency were calculated weekly. The experiment lasted for five weeks. The results showed that total Dry Matter Intake for Treatment 1 was the highest (3285 g), and Dry Matter Intakes for Treatments 2, 3 and 4 (3284 g, 3284 g and 3284 g) were not significantly different (P > 0.05) and Dry Matter Intake for Treatment 5 was the lowest (3282 g). Weight gains for Treatments 1 and 2 (2089 g and 2089 g) were not different (P > 0.05), Treatments 3 and 4 (2098 g and 2103 g) were not different (P > 0.05) and Treatment 5 had the lowest gain of 1990 g. Feed Conversion Ratio for Treatments 1 and 2 (1.572 and 1.572) was not significantly different (P > 0.05), Treatments 3 and 4 (1.565 and 1.562) were not different (P > 0.05) and Treatment 5 had the highest FCR (1.64). The bioeconomic efficiency results were significantly different (P < 0.05) for Treatments 1, 2, 3, 4 and 5 (42.16, 41.93, 41.46, 41.13 and 42.66, respectively). Based on the analyses and results, the authors concluded that cowpea meal prepared from boiled cowpea grain can be used to replace soybean meal in broiler diets at 50% and 75% inclusion, respectively. This study is unique and interesting and suitable for acceptance in this journal because it seeks to provide an alternative to feeds for the ever-growing broiler industry in Zimbabwe and the rest of the world.展开更多
This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of ...This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of soybean in Zimbabwe due to droughts, inadequate irrigation infrastructure, high input costs, and price controls, the authors identified an alternative to soybean meal in cowpea meal due to its availability and similar amino acid profile to soybean meal. The experiment was carried out at Cold Storage Company in Kadoma. A total of 150 unsexed day-old broiler chicks (Cobb 500) were used. All the birds were brooded in one pen during the first two weeks of age and fed with standard broiler starter mash from National Foods PVT LTD for adaptation. The birds were randomly allocated into five equal groups, each with three replicates and 10 birds per replicate at three weeks of age. Five experimental diets: T1 (100% soybean meal + 0% cowpeas meal), T2 (75% soybean meal + 25% cowpeas meal), T3 (50% soybean meal + 50% cowpeas meal), T4 (25% soybean meal + 75% cowpeas meal) and T5 (0% soybean meal + 100% cowpeas meal) were formulated to be iso-caloric and iso-nitrogenous to meet nutrient requirements of broilers according to NRC (2001). Ration formulation using maize, soybean and cowpea meal as ingredients for broiler starter (21% Crude Protein) and broiler finisher (19% Crude Protein) was done using the Pearson Square Method. Feed intake (g) and weight gain (g) were recorded weekly. Feed Conversion Ratio (FCR) and bioeconomic efficiency were calculated weekly. The experiment lasted for five weeks. The results showed that total Dry Matter Intake for Treatment 1 was the highest (3285 g), and Dry Matter Intakes for Treatments 2, 3 and 4 (3284 g, 3284 g and 3284 g) were not significantly different (P > 0.05) and Dry Matter Intake for Treatment 5 was the lowest (3282 g). Weight gains for Treatments 1 and 2 (2089 g and 2089 g) were not different (P > 0.05), Treatments 3 and 4 (2098 g and 2103 g) were not different (P > 0.05) and Treatment 5 had the lowest gain of 1990 g. Feed Conversion Ratio for Treatments 1 and 2 (1.572 and 1.572) was not significantly different (P > 0.05), Treatments 3 and 4 (1.565 and 1.562) were not different (P > 0.05) and Treatment 5 had the highest FCR (1.64). The bioeconomic efficiency results were significantly different (P < 0.05) for Treatments 1, 2, 3, 4 and 5 (42.16, 41.93, 41.46, 41.13 and 42.66, respectively). Based on the analyses and results, the authors concluded that cowpea meal prepared from boiled cowpea grain can be used to replace soybean meal in broiler diets at 50% and 75% inclusion, respectively. This study is unique and interesting and suitable for acceptance in this journal because it seeks to provide an alternative to feeds for the ever-growing broiler industry in Zimbabwe and the rest of the world.展开更多
基金Project (2011CB606302-1) supported by the National Basic Research Program of ChinaProject (2013AA031001) supported by Hi-Tech Research and Development Program of China
文摘A self-developed forced convection rheoforming （FCR） machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at different stirring speeds prepared by the FCR process were analyzed. The experimental results suggest that with the increase of the stirring speed, the mean grain size of the semisolid decreases and the shape factor as well as the number of primary grains increase. Meanwhile, the preparation process of semisolid slurry was numerically simulated. The flow characteristics of the melt in the device and the effect of the stirring speed on temperature field and solid fraction of the melt were investigated. The simulated results show that during the preparation process of semisolid slurry, there is a complex convection within the FCR device that obviously changes the temperature field distribution and solid fraction of the melt. When the convection intensity increases, the scope of the undercooling gradient of the melt is reduced and temperature distribution is improved.
文摘This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of soybean in Zimbabwe due to droughts, inadequate irrigation infrastructure, high input costs, and price controls, the authors identified an alternative to soybean meal in cowpea meal due to its availability and similar amino acid profile to soybean meal. The experiment was carried out at Cold Storage Company in Kadoma. A total of 150 unsexed day-old broiler chicks (Cobb 500) were used. All the birds were brooded in one pen during the first two weeks of age and fed with standard broiler starter mash from National Foods PVT LTD for adaptation. The birds were randomly allocated into five equal groups, each with three replicates and 10 birds per replicate at three weeks of age. Five experimental diets: T1 (100% soybean meal + 0% cowpeas meal), T2 (75% soybean meal + 25% cowpeas meal), T3 (50% soybean meal + 50% cowpeas meal), T4 (25% soybean meal + 75% cowpeas meal) and T5 (0% soybean meal + 100% cowpeas meal) were formulated to be iso-caloric and iso-nitrogenous to meet nutrient requirements of broilers according to NRC (2001). Ration formulation using maize, soybean and cowpea meal as ingredients for broiler starter (21% Crude Protein) and broiler finisher (19% Crude Protein) was done using the Pearson Square Method. Feed intake (g) and weight gain (g) were recorded weekly. Feed Conversion Ratio (FCR) and bioeconomic efficiency were calculated weekly. The experiment lasted for five weeks. The results showed that total Dry Matter Intake for Treatment 1 was the highest (3285 g), and Dry Matter Intakes for Treatments 2, 3 and 4 (3284 g, 3284 g and 3284 g) were not significantly different (P > 0.05) and Dry Matter Intake for Treatment 5 was the lowest (3282 g). Weight gains for Treatments 1 and 2 (2089 g and 2089 g) were not different (P > 0.05), Treatments 3 and 4 (2098 g and 2103 g) were not different (P > 0.05) and Treatment 5 had the lowest gain of 1990 g. Feed Conversion Ratio for Treatments 1 and 2 (1.572 and 1.572) was not significantly different (P > 0.05), Treatments 3 and 4 (1.565 and 1.562) were not different (P > 0.05) and Treatment 5 had the highest FCR (1.64). The bioeconomic efficiency results were significantly different (P < 0.05) for Treatments 1, 2, 3, 4 and 5 (42.16, 41.93, 41.46, 41.13 and 42.66, respectively). Based on the analyses and results, the authors concluded that cowpea meal prepared from boiled cowpea grain can be used to replace soybean meal in broiler diets at 50% and 75% inclusion, respectively. This study is unique and interesting and suitable for acceptance in this journal because it seeks to provide an alternative to feeds for the ever-growing broiler industry in Zimbabwe and the rest of the world.
文摘This manuscript explores the biological and economic efficiency of partial dietary substitution of soybean (Glycine max) meal with cowpea (Vigna unguiculata) meal in broiler production. As a result of the shortage of soybean in Zimbabwe due to droughts, inadequate irrigation infrastructure, high input costs, and price controls, the authors identified an alternative to soybean meal in cowpea meal due to its availability and similar amino acid profile to soybean meal. The experiment was carried out at Cold Storage Company in Kadoma. A total of 150 unsexed day-old broiler chicks (Cobb 500) were used. All the birds were brooded in one pen during the first two weeks of age and fed with standard broiler starter mash from National Foods PVT LTD for adaptation. The birds were randomly allocated into five equal groups, each with three replicates and 10 birds per replicate at three weeks of age. Five experimental diets: T1 (100% soybean meal + 0% cowpeas meal), T2 (75% soybean meal + 25% cowpeas meal), T3 (50% soybean meal + 50% cowpeas meal), T4 (25% soybean meal + 75% cowpeas meal) and T5 (0% soybean meal + 100% cowpeas meal) were formulated to be iso-caloric and iso-nitrogenous to meet nutrient requirements of broilers according to NRC (2001). Ration formulation using maize, soybean and cowpea meal as ingredients for broiler starter (21% Crude Protein) and broiler finisher (19% Crude Protein) was done using the Pearson Square Method. Feed intake (g) and weight gain (g) were recorded weekly. Feed Conversion Ratio (FCR) and bioeconomic efficiency were calculated weekly. The experiment lasted for five weeks. The results showed that total Dry Matter Intake for Treatment 1 was the highest (3285 g), and Dry Matter Intakes for Treatments 2, 3 and 4 (3284 g, 3284 g and 3284 g) were not significantly different (P > 0.05) and Dry Matter Intake for Treatment 5 was the lowest (3282 g). Weight gains for Treatments 1 and 2 (2089 g and 2089 g) were not different (P > 0.05), Treatments 3 and 4 (2098 g and 2103 g) were not different (P > 0.05) and Treatment 5 had the lowest gain of 1990 g. Feed Conversion Ratio for Treatments 1 and 2 (1.572 and 1.572) was not significantly different (P > 0.05), Treatments 3 and 4 (1.565 and 1.562) were not different (P > 0.05) and Treatment 5 had the highest FCR (1.64). The bioeconomic efficiency results were significantly different (P < 0.05) for Treatments 1, 2, 3, 4 and 5 (42.16, 41.93, 41.46, 41.13 and 42.66, respectively). Based on the analyses and results, the authors concluded that cowpea meal prepared from boiled cowpea grain can be used to replace soybean meal in broiler diets at 50% and 75% inclusion, respectively. This study is unique and interesting and suitable for acceptance in this journal because it seeks to provide an alternative to feeds for the ever-growing broiler industry in Zimbabwe and the rest of the world.
