An experiment was conducted to investigate the requirement of nonphytate phosphorus（nPP） and efficacy of a genetically engineered yeast phytase（PHY A） for Lingnan yellow broilers from 22-to 42-d-old age.A total of...An experiment was conducted to investigate the requirement of nonphytate phosphorus（nPP） and efficacy of a genetically engineered yeast phytase（PHY A） for Lingnan yellow broilers from 22-to 42-d-old age.A total of 1 320 1-d-old male chicks were randomly divided into 11 dietary treatment groups,which consisted of 4 replicate floor pens with 30 birds per pen.The control group（treatment 1） was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation.Dietary levels of nPP were 0.16,0.24,0.32,0.40,0.48,and 0.56%,respectively,for treatments 2 to 7,through addition of dicalcium phosphate（chemistry grade） to the basal diet.Diets of treatments 8 to 11 were supplemented with PHY A at 200,400 and 600 U kg-1,a commercial phytase product（PHY B） at 400 U kg-1 level,respectively.The birds in 0.32-0.56% nPP groups gained more than those of the other groups（P0.05）.The nPP supplementation significantly improved feed intake（P0.05）.The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds（P0.05）.The level of 0.48% nPP was required for optimum tibia development.The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG（P0.05）,ADFI（P0.05）,and dry defatted tibia weight（P0.05）.Similarly,the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation（P0.05）.The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%.The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22-to 42-d-old age.展开更多
This experiment was conducted to determine whether dietary cholecalciferol will alleviate a calcium and phosphorous(Ca-P) deficiency when one-alpha-hydroxy-cholecalciferol,1 a(OH)D_3,is supplemented,and to determine t...This experiment was conducted to determine whether dietary cholecalciferol will alleviate a calcium and phosphorous(Ca-P) deficiency when one-alpha-hydroxy-cholecalciferol,1 a(OH)D_3,is supplemented,and to determine the effects of adequate and inadequate Ca-P when 1 a(OH)D_3 is supplemented and vitamin D_3 is adequate.A total of 144 one-d-old broiler chicks(Ross 308) were allocated to 3 treatments.The dietary treatments were as follows: treatment A,adequate Ca-P + cholecalciferol + 5 mg/kg 1 a(OH)D_3;treatment B,inadequate Ca-P + cholecalciferol + 5 mg/kg 1 a(OH)D_3; treatment C,inadequate Ca-P + 5 mg/kg 1 a(OH)D_3.All diets were mixed with 500 FTU/kg of phytase,and cholecalciferol was provided in 5,000 IU/kg except for treatment C that fed diets without vitamin D_3.The Ca-P levels in the adequate diets were 0.90% Ca,0.66% total phosphorus(t P); 0.75% Ca,0.59% t P; 0.69% Ca,0.54% t P for the starter,grower and finisher periods.At d 42 of age,broilers were inspected for incidence and severity of tibial dyschondroplasia(TD).The results showed that inadequate Ca-P supplementation with cholecalciferol significantly decreased the incidence of TD,score and tibia ash compared with broilers fed the same diet in the absence of cholecalciferol(P < 0.05).The broilers fed inadequate Ca-P diets with cholecalciferol were unable to achieve the same tibia ash and incidence of TD as those fed Ca-P adequate diets(P < 0.05).In conclusion,this trial suggests that broilers fed an inadequate Ca-P diet with 1 a(OH)D_3 and adequate level of cholecalciferol are unable to sufficient bone formation.There was no indication that 1 a(OH)D_3 in the absence of cholecalciferol was effective in reducing TD whereas it could improve tibia ash.展开更多
The interaction of xylanase, protease and superdosing(1,500 FTU/kg) phytase in a 2×2×2 factorial arrangement was studied in broilers fed sorghum-based diets. A total of 2,800 one-day-old unsexed Ross308 chic...The interaction of xylanase, protease and superdosing(1,500 FTU/kg) phytase in a 2×2×2 factorial arrangement was studied in broilers fed sorghum-based diets. A total of 2,800 one-day-old unsexed Ross308 chicks were housed in 56 pens with 50 birds per pen, with or without inclusion of xylanase, protease and phytase, totaling 8 treatments and 7 replicates per treatment. Body weight(BW) and feed intake(FI)were measured at 21 and 42 days of age, and mortality corrected feed conversion ratio(FCR) was calculated for each period and cumulatively. Tibia ash and carcass yield were determined in 2 birds per replicate at 21 and 42 days of age, respectively. Digesta transit time was determined at 21, 28, 35 and 42 days of age using 5 birds per replicate. Results showed that superdosing phytase increased BW and FI at42 days of age(P < 0.05) and xylanase improved FCR(P < 0.05). Xylanase and phytase also positively influenced carcass yield and breast weight, respectively. Overall, inclusion of superdosing phytase increased transit time when included in a diet containing xylanase, and no change with protease inclusion. In conclusion, the beneficial effects of xylanase, protease and superdosing phytase in broiler performance were not additive. This limitation is likely not related to the lack of efficacy of any one of the individual enzymes but to a limitation of the bird to respond additively to successive additions of enzymes.展开更多
基金supported by the the Earmarked Fund for Modern Agro-Industry Technology Research System,China (nycytx-42-G2-01)the grant from Ministry of Agriculture of China (nyhyzx07-038)
文摘An experiment was conducted to investigate the requirement of nonphytate phosphorus（nPP） and efficacy of a genetically engineered yeast phytase（PHY A） for Lingnan yellow broilers from 22-to 42-d-old age.A total of 1 320 1-d-old male chicks were randomly divided into 11 dietary treatment groups,which consisted of 4 replicate floor pens with 30 birds per pen.The control group（treatment 1） was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation.Dietary levels of nPP were 0.16,0.24,0.32,0.40,0.48,and 0.56%,respectively,for treatments 2 to 7,through addition of dicalcium phosphate（chemistry grade） to the basal diet.Diets of treatments 8 to 11 were supplemented with PHY A at 200,400 and 600 U kg-1,a commercial phytase product（PHY B） at 400 U kg-1 level,respectively.The birds in 0.32-0.56% nPP groups gained more than those of the other groups（P0.05）.The nPP supplementation significantly improved feed intake（P0.05）.The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds（P0.05）.The level of 0.48% nPP was required for optimum tibia development.The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG（P0.05）,ADFI（P0.05）,and dry defatted tibia weight（P0.05）.Similarly,the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation（P0.05）.The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%.The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22-to 42-d-old age.
基金support from the Young Researchers and Elite Club,Isfahan Branch (Grant No.2016/ 003)
文摘This experiment was conducted to determine whether dietary cholecalciferol will alleviate a calcium and phosphorous(Ca-P) deficiency when one-alpha-hydroxy-cholecalciferol,1 a(OH)D_3,is supplemented,and to determine the effects of adequate and inadequate Ca-P when 1 a(OH)D_3 is supplemented and vitamin D_3 is adequate.A total of 144 one-d-old broiler chicks(Ross 308) were allocated to 3 treatments.The dietary treatments were as follows: treatment A,adequate Ca-P + cholecalciferol + 5 mg/kg 1 a(OH)D_3;treatment B,inadequate Ca-P + cholecalciferol + 5 mg/kg 1 a(OH)D_3; treatment C,inadequate Ca-P + 5 mg/kg 1 a(OH)D_3.All diets were mixed with 500 FTU/kg of phytase,and cholecalciferol was provided in 5,000 IU/kg except for treatment C that fed diets without vitamin D_3.The Ca-P levels in the adequate diets were 0.90% Ca,0.66% total phosphorus(t P); 0.75% Ca,0.59% t P; 0.69% Ca,0.54% t P for the starter,grower and finisher periods.At d 42 of age,broilers were inspected for incidence and severity of tibial dyschondroplasia(TD).The results showed that inadequate Ca-P supplementation with cholecalciferol significantly decreased the incidence of TD,score and tibia ash compared with broilers fed the same diet in the absence of cholecalciferol(P < 0.05).The broilers fed inadequate Ca-P diets with cholecalciferol were unable to achieve the same tibia ash and incidence of TD as those fed Ca-P adequate diets(P < 0.05).In conclusion,this trial suggests that broilers fed an inadequate Ca-P diet with 1 a(OH)D_3 and adequate level of cholecalciferol are unable to sufficient bone formation.There was no indication that 1 a(OH)D_3 in the absence of cholecalciferol was effective in reducing TD whereas it could improve tibia ash.
文摘The interaction of xylanase, protease and superdosing(1,500 FTU/kg) phytase in a 2×2×2 factorial arrangement was studied in broilers fed sorghum-based diets. A total of 2,800 one-day-old unsexed Ross308 chicks were housed in 56 pens with 50 birds per pen, with or without inclusion of xylanase, protease and phytase, totaling 8 treatments and 7 replicates per treatment. Body weight(BW) and feed intake(FI)were measured at 21 and 42 days of age, and mortality corrected feed conversion ratio(FCR) was calculated for each period and cumulatively. Tibia ash and carcass yield were determined in 2 birds per replicate at 21 and 42 days of age, respectively. Digesta transit time was determined at 21, 28, 35 and 42 days of age using 5 birds per replicate. Results showed that superdosing phytase increased BW and FI at42 days of age(P < 0.05) and xylanase improved FCR(P < 0.05). Xylanase and phytase also positively influenced carcass yield and breast weight, respectively. Overall, inclusion of superdosing phytase increased transit time when included in a diet containing xylanase, and no change with protease inclusion. In conclusion, the beneficial effects of xylanase, protease and superdosing phytase in broiler performance were not additive. This limitation is likely not related to the lack of efficacy of any one of the individual enzymes but to a limitation of the bird to respond additively to successive additions of enzymes.
