Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:...Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:1. The second hypothesis was that increasing dietary Ca increases plasma Ca concentration and downregulates abundance of genes related to Ca absorption(TRPV6, S100 G, and ATP2 B1) in the duodenum, and tight junction proteins(OCLN, CLDN1, and ZO1) in the duodenum and ileum.Methods: Twenty corn-soybean meal diets were formulated using a 4 × 5 factorial design with diets containing 0.16%, 0.33%, 0.42%, or 0.50% STTD P, and 0.14%, 0.29%, 0.44%, 0.59%, or 0.74% STTD Ca. Six hundred and forty pigs(initial weight: 11.1 ± 1.4 kg) were allotted to 20 diets and 5 blocks in a randomized complete block design. On day21, weights of pigs and feed left in feeders were recorded and blood, duodenal tissue, ileal mucosa, and the right femur were collected from 1 pig per pen. Abundance of m RNA was determined in duodenal and ileal tissue via quantitative RT-PCR. Data were analyzed using a response surface model.Results: The predicted maximum ADG(614 g), G:F(0.65), and bone ash(11.68 g) was obtained at STTD Ca:STTD P ratios of 1.39:1, 1.25:1, and 1.66:1, respectively, when STTD P was provided at the requirement(0.33%). If dietary STTD P was below the requirement, increasing dietary Ca resulted in reduced(P < 0.05) ADG and G:F. However, if dietary STTD P was above the requirement, negative effects(P < 0.05) on ADG and G:F of increasing STTD Ca were observed only if dietary STTD Ca exceeded 0.6%. Plasma Ca concentration was positively affected by STTD Ca over the range studied(quadratic, P < 0.01) and negatively affected by increasing STTD P(linear, P < 0.01). There was a linear negative effect(P < 0.05) of STTD Ca on the abundance of S100 G, TRPV6, OCLN, and ZO1 in duodenum, and CLDN and ZO1 in ileum.Conclusions: The STTD Ca:STTD P ratio needed to maximize growth performance of 11-to 25-kg pigs is less than1.40:1, if P is at the estimated requirement. Increasing dietary Ca reduces transcellular absorption of Ca and increases paracellular absorption of Ca.展开更多
Three experiments were conducted to evaluate the phosphorus(P) utilization responses of pigs and broiler chickens to dietary supplementation with antimicrobials and phytase and to determine if P digestibility response...Three experiments were conducted to evaluate the phosphorus(P) utilization responses of pigs and broiler chickens to dietary supplementation with antimicrobials and phytase and to determine if P digestibility response to phytase is affected by supplementation with antimicrobials. Experiment 1 used 4 diets(a basal negative control formulated to contain 0.41% total P and 0.71% calcium [Ca] without added antimicrobials, basal negative control with added carbadox, basal negative control with added tylosin, or basal negative control with added virginiamycin) and six 18-kg barrows in individual metabolism crates per diet. There was no effect of antimicrobials on P and Ca digestibility or retention. Carbadox supplementation increased(P < 0.05) digestibility and retention of gross energy(GE) and supplementation with tylosin increased(P < 0.05) N retention relative to the basal negative control diet. Experiment 2 used eight 19-kg barrows in individual metabolism crates per treatment and 9 dietary treatments arranged in a 3×3 factorial of antimicrobials(none, tylosin, or virginiamycin) and phytase(0, 500, or 1,500 FTU/kg).Phytase addition to the diets linearly increased(P< 0.05) apparent total tract digestibility or retention of P, Ca, nitrogen(N) and GE. Supplementation with antimicrobials did not affect apparent total tract digestibility or retention of P, Ca, N or GE. There were linear effects(P < 0.01) of phytase on Ca utilization in diets that were not supplemented with antimicrobials but only tendencies(P < 0,10) in diets supplemented with tylosin or virginiamycin. Phytase linearly improved(P < 0.05) N utilization in diets supplemented with tylosin or virginiamycin but not in diets without added antimicrobials. Experiment 3 was a broiler chicken experiment with the same experimental design as Exp. 2 but feeding 8 birds per cage and 10 replicate cages per diet. Antimicrobial supplementation improved(P < 0.05) feed efficiency and adding tylosin improved(P < 0.05) tibia ash but did not affect nutrient utilization, Dietary phytase improved(P < 0.01) growth performance, tibia ash and apparent ileal digestibility and retention of P regardless of antimicrobial supplementation. Overall, phytase supplementation improved growth performance and nutrient digestibility and retention, regardless of supplementation of diets with antimicrobials. Supplementation of diets with antimicrobials did not affect P digestibility or retention because of a lack of interaction between antimicrobials and phytase, there was no evidence that P digestibility response to phytase is affected by supplementation with antimicrobials.展开更多
Measurements of total phytate phosphorus content of diets may be deceptive as they do not indicate substrate availability for phytase; it may be that measurements of phytate susceptible to phytase effects are a more a...Measurements of total phytate phosphorus content of diets may be deceptive as they do not indicate substrate availability for phytase; it may be that measurements of phytate susceptible to phytase effects are a more accurate measure of phosphorus(P) availability to the bird. To verify this hypothesis, an experiment was conducted to compare diets formulated to contain either high or low susceptible phytate, supplemented with either 0 or 500 FTU/kg phytase. Susceptible phytate was determined by exposing the feed samples to conditions that mimicked the average pH of the proximal gastrointestinal tract(pH 4.5) and the optimum temperature for phytase activity(37℃) and then measuring phytate dissolved. Ross 308 birds(n = 240) were fed one of 4 dietary treatments in a 2 x 2 factorial design; 2 diets with high(8.54 g/kg, 57.90% of total phytate) or low(5.77 g/kg, 46.33% of total phytate) susceptible phytate, containing 0 or 500 FTU/kg phytase. Diets were fed to broilers(12 replicate pens of 5 birds per pen) from d 0 to 28 post hatch. Birds fed diets high in susceptible phytate had greater phytate hydrolysis in the gizzard(P < 0.001), jejunum(P < 0.001) and ileum(P < 0.001) and resulting greater body weight gain(BWG)(P = 0.015) and lower FCR(P = 0.003) than birds fed the low susceptible phytate diets,irrespective of phytase presence. Birds fed the high susceptible diets also had greater P solubility in the gizzard and Ca and P solubility in the jejunum and ileum(P < 0.05) and resulting greater tibia and femur Ca and P(P < 0.05) content than those fed the low susceptible diets. All the susceptible phytate was fully degraded in the tract in the absence of added phytase, suggesting the assay used in this study was able to successfully estimate the amount of total dietary phytate that was susceptible to the effects of phytase when used at standard levels. No interactions were observed between susceptible phytate and phytase on phytate hydrolysis. Hydrolysis of phytate was greater(P < 0.05) in the gizzard of birds fed the diets supplemented with phytase, regardless of the concentration of susceptible phytate in the diet. Phytase supplementation resulted in improved BWG(P < 0.001) and FCR(P = 0.001), increased P solubility(P < 0.001) in the gizzard, Ca and P solubility(P < 0.001) in the jejunum and ileum and Ca and P concentration(P < 0.001) and strength(P < 0.001) in the tibia and femur. Pepsin activity was higher in birds fed the diets supplemented with phytase(P < 0.001) and was greater(P = 0.031) in birds fed the high susceptible phytate diets compared with the low susceptible phytate diets. Findings from this study suggest that there may be a measure more meaningful to animal nutritionists than measurements of total phytate.展开更多
An experiment was conducted to determine the standardized ileal digestible(SID)calcium requirement of fast-growing broilers from hatch to d 14 post-hatch.Ross 308(n=360)male broilers were obtained on day of hatch and ...An experiment was conducted to determine the standardized ileal digestible(SID)calcium requirement of fast-growing broilers from hatch to d 14 post-hatch.Ross 308(n=360)male broilers were obtained on day of hatch and allocated to 1 of 5 treatments in battery cages.There were 6 birds per cage and 12 pens per treatment.Four treatments were formulated to contain 0.60%,0.46%,0.32%or 0.18%SID Ca.The final treatment was formulated using total Ca to meet or exceed all nutrient requirements,including 0.90%total Ca and 0.49%non-phytate P(nPP),using the same ingredients.This treatment was the reference diet for comparison and validation of the SID Ca diets.Birds and feed were weighed at placement and on d 14.Tibias and ileal contents were obtained on d 14 and excreta was collected per pen and pooled on d 14.Data were analyzed using JMP Pro and requirements were estimated using 3different non-linear regression models.Increasing the SID Ca content in the diet from 0.18%to 0.60%improved(quadratic,P<0.05)body weight gain and mortality corrected feed conversion ratio(mFCR).The estimated SID Ca requirement to optimize gain or m FCR was between 0.39%and 0.52%.Tibia ash percent and weight increased(quadratic,P<0.05)as SID Ca content in the diet increased and the estimated SID Ca requirement was between 0.32%and 0.58%.Phosphorus utilization was improved in birds fed diets formulated using SID Ca compared with birds fed the reference diet.In conclusion,the SID Ca requirement of fast-growing broilers from hatch to d 14 was estimated between 0.534%and 0.398%when quadratic,straight-broken line,or quadratic-broken line regressions were used.These results agree with previously published data evaluating the SID Ca requirement of fast-growth broilers from hatch to d 10.展开更多
基金Financial support for this research from AB Vista,Marlborough,UK
文摘Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:1. The second hypothesis was that increasing dietary Ca increases plasma Ca concentration and downregulates abundance of genes related to Ca absorption(TRPV6, S100 G, and ATP2 B1) in the duodenum, and tight junction proteins(OCLN, CLDN1, and ZO1) in the duodenum and ileum.Methods: Twenty corn-soybean meal diets were formulated using a 4 × 5 factorial design with diets containing 0.16%, 0.33%, 0.42%, or 0.50% STTD P, and 0.14%, 0.29%, 0.44%, 0.59%, or 0.74% STTD Ca. Six hundred and forty pigs(initial weight: 11.1 ± 1.4 kg) were allotted to 20 diets and 5 blocks in a randomized complete block design. On day21, weights of pigs and feed left in feeders were recorded and blood, duodenal tissue, ileal mucosa, and the right femur were collected from 1 pig per pen. Abundance of m RNA was determined in duodenal and ileal tissue via quantitative RT-PCR. Data were analyzed using a response surface model.Results: The predicted maximum ADG(614 g), G:F(0.65), and bone ash(11.68 g) was obtained at STTD Ca:STTD P ratios of 1.39:1, 1.25:1, and 1.66:1, respectively, when STTD P was provided at the requirement(0.33%). If dietary STTD P was below the requirement, increasing dietary Ca resulted in reduced(P < 0.05) ADG and G:F. However, if dietary STTD P was above the requirement, negative effects(P < 0.05) on ADG and G:F of increasing STTD Ca were observed only if dietary STTD Ca exceeded 0.6%. Plasma Ca concentration was positively affected by STTD Ca over the range studied(quadratic, P < 0.01) and negatively affected by increasing STTD P(linear, P < 0.01). There was a linear negative effect(P < 0.05) of STTD Ca on the abundance of S100 G, TRPV6, OCLN, and ZO1 in duodenum, and CLDN and ZO1 in ileum.Conclusions: The STTD Ca:STTD P ratio needed to maximize growth performance of 11-to 25-kg pigs is less than1.40:1, if P is at the estimated requirement. Increasing dietary Ca reduces transcellular absorption of Ca and increases paracellular absorption of Ca.
文摘Three experiments were conducted to evaluate the phosphorus(P) utilization responses of pigs and broiler chickens to dietary supplementation with antimicrobials and phytase and to determine if P digestibility response to phytase is affected by supplementation with antimicrobials. Experiment 1 used 4 diets(a basal negative control formulated to contain 0.41% total P and 0.71% calcium [Ca] without added antimicrobials, basal negative control with added carbadox, basal negative control with added tylosin, or basal negative control with added virginiamycin) and six 18-kg barrows in individual metabolism crates per diet. There was no effect of antimicrobials on P and Ca digestibility or retention. Carbadox supplementation increased(P < 0.05) digestibility and retention of gross energy(GE) and supplementation with tylosin increased(P < 0.05) N retention relative to the basal negative control diet. Experiment 2 used eight 19-kg barrows in individual metabolism crates per treatment and 9 dietary treatments arranged in a 3×3 factorial of antimicrobials(none, tylosin, or virginiamycin) and phytase(0, 500, or 1,500 FTU/kg).Phytase addition to the diets linearly increased(P< 0.05) apparent total tract digestibility or retention of P, Ca, nitrogen(N) and GE. Supplementation with antimicrobials did not affect apparent total tract digestibility or retention of P, Ca, N or GE. There were linear effects(P < 0.01) of phytase on Ca utilization in diets that were not supplemented with antimicrobials but only tendencies(P < 0,10) in diets supplemented with tylosin or virginiamycin. Phytase linearly improved(P < 0.05) N utilization in diets supplemented with tylosin or virginiamycin but not in diets without added antimicrobials. Experiment 3 was a broiler chicken experiment with the same experimental design as Exp. 2 but feeding 8 birds per cage and 10 replicate cages per diet. Antimicrobial supplementation improved(P < 0.05) feed efficiency and adding tylosin improved(P < 0.05) tibia ash but did not affect nutrient utilization, Dietary phytase improved(P < 0.01) growth performance, tibia ash and apparent ileal digestibility and retention of P regardless of antimicrobial supplementation. Overall, phytase supplementation improved growth performance and nutrient digestibility and retention, regardless of supplementation of diets with antimicrobials. Supplementation of diets with antimicrobials did not affect P digestibility or retention because of a lack of interaction between antimicrobials and phytase, there was no evidence that P digestibility response to phytase is affected by supplementation with antimicrobials.
文摘Measurements of total phytate phosphorus content of diets may be deceptive as they do not indicate substrate availability for phytase; it may be that measurements of phytate susceptible to phytase effects are a more accurate measure of phosphorus(P) availability to the bird. To verify this hypothesis, an experiment was conducted to compare diets formulated to contain either high or low susceptible phytate, supplemented with either 0 or 500 FTU/kg phytase. Susceptible phytate was determined by exposing the feed samples to conditions that mimicked the average pH of the proximal gastrointestinal tract(pH 4.5) and the optimum temperature for phytase activity(37℃) and then measuring phytate dissolved. Ross 308 birds(n = 240) were fed one of 4 dietary treatments in a 2 x 2 factorial design; 2 diets with high(8.54 g/kg, 57.90% of total phytate) or low(5.77 g/kg, 46.33% of total phytate) susceptible phytate, containing 0 or 500 FTU/kg phytase. Diets were fed to broilers(12 replicate pens of 5 birds per pen) from d 0 to 28 post hatch. Birds fed diets high in susceptible phytate had greater phytate hydrolysis in the gizzard(P < 0.001), jejunum(P < 0.001) and ileum(P < 0.001) and resulting greater body weight gain(BWG)(P = 0.015) and lower FCR(P = 0.003) than birds fed the low susceptible phytate diets,irrespective of phytase presence. Birds fed the high susceptible diets also had greater P solubility in the gizzard and Ca and P solubility in the jejunum and ileum(P < 0.05) and resulting greater tibia and femur Ca and P(P < 0.05) content than those fed the low susceptible diets. All the susceptible phytate was fully degraded in the tract in the absence of added phytase, suggesting the assay used in this study was able to successfully estimate the amount of total dietary phytate that was susceptible to the effects of phytase when used at standard levels. No interactions were observed between susceptible phytate and phytase on phytate hydrolysis. Hydrolysis of phytate was greater(P < 0.05) in the gizzard of birds fed the diets supplemented with phytase, regardless of the concentration of susceptible phytate in the diet. Phytase supplementation resulted in improved BWG(P < 0.001) and FCR(P = 0.001), increased P solubility(P < 0.001) in the gizzard, Ca and P solubility(P < 0.001) in the jejunum and ileum and Ca and P concentration(P < 0.001) and strength(P < 0.001) in the tibia and femur. Pepsin activity was higher in birds fed the diets supplemented with phytase(P < 0.001) and was greater(P = 0.031) in birds fed the high susceptible phytate diets compared with the low susceptible phytate diets. Findings from this study suggest that there may be a measure more meaningful to animal nutritionists than measurements of total phytate.
文摘An experiment was conducted to determine the standardized ileal digestible(SID)calcium requirement of fast-growing broilers from hatch to d 14 post-hatch.Ross 308(n=360)male broilers were obtained on day of hatch and allocated to 1 of 5 treatments in battery cages.There were 6 birds per cage and 12 pens per treatment.Four treatments were formulated to contain 0.60%,0.46%,0.32%or 0.18%SID Ca.The final treatment was formulated using total Ca to meet or exceed all nutrient requirements,including 0.90%total Ca and 0.49%non-phytate P(nPP),using the same ingredients.This treatment was the reference diet for comparison and validation of the SID Ca diets.Birds and feed were weighed at placement and on d 14.Tibias and ileal contents were obtained on d 14 and excreta was collected per pen and pooled on d 14.Data were analyzed using JMP Pro and requirements were estimated using 3different non-linear regression models.Increasing the SID Ca content in the diet from 0.18%to 0.60%improved(quadratic,P<0.05)body weight gain and mortality corrected feed conversion ratio(mFCR).The estimated SID Ca requirement to optimize gain or m FCR was between 0.39%and 0.52%.Tibia ash percent and weight increased(quadratic,P<0.05)as SID Ca content in the diet increased and the estimated SID Ca requirement was between 0.32%and 0.58%.Phosphorus utilization was improved in birds fed diets formulated using SID Ca compared with birds fed the reference diet.In conclusion,the SID Ca requirement of fast-growing broilers from hatch to d 14 was estimated between 0.534%and 0.398%when quadratic,straight-broken line,or quadratic-broken line regressions were used.These results agree with previously published data evaluating the SID Ca requirement of fast-growth broilers from hatch to d 10.
