Background The effect of microbial phytase on amino acid and energy digestibility is not consistent in pigs,which may be related to the phytase dosage or the adaptation length to the diet.Therefore,an experiment was c...Background The effect of microbial phytase on amino acid and energy digestibility is not consistent in pigs,which may be related to the phytase dosage or the adaptation length to the diet.Therefore,an experiment was conducted to test the hypotheses that increasing dietary phytase after an 18-day adaptation period:1)increases nutrient and energy digestibility;2)increases plasma P,plasma inositol,and bone ash of young pigs;and 3)demonstrates that maximum phytate degradation requires more phytase than maximum P digestibility.Results Data indicated that increasing inclusion of phytase[0,250,500,1,000,2,000,and 4,000 phytase units(FTU)/kg feed]in corn-soybean meal-based diets increased apparent ileal digestibility(AID)of Trp(quadratic;P<0.05),and of Lys and Thr(linear;P<0.05),and tended to increase AID of Met(linear;P<0.10).Increasing dietary phytase also increased AID and apparent total tract digestibility(ATTD)of Ca and P(quadratic;P<0.05)and increased ATTD of K and Na(linear;P<0.05),but phytase did not influence the ATTD of Mg or gross energy.Concentrations of plasma P and bone ash increased(quadratic;P<0.05),and plasma inositol also increased(linear;P<0.05)with increasing inclusion of phytase.Reduced concentrations of inositol phosphate(IP)6 and IP5(quadratic;P<0.05),reduced IP4 and IP3(linear;P<0.05),but increased inositol concentrations(linear;P<0.05)were observed in ileal digesta as dietary phytase increased.The ATTD of P was maximized if at least 1,200 FTU/kg were used,whereas more than 4,000 FTU/kg were needed to maximize inositol release.Conclusions Increasing dietary levels of phytase after an 18-day adaptation period increased phytate and IP ester degradation and inositol release in the small intestine.Consequently,increasing dietary phytase resulted in improved digestibility of Ca,P,K,Na,and the first 4 limiting amino acids,and in increased concentrations of bone ash and plasma P and inositol.In a corn-soybean meal diet,maximum inositol release requires approximately 3,200 FTU/kg more phytase than that required for maximum P digestibility.展开更多
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
基金support for this research from AB Vista,Marlborough,UK,is greatly appreciated。
文摘Background The effect of microbial phytase on amino acid and energy digestibility is not consistent in pigs,which may be related to the phytase dosage or the adaptation length to the diet.Therefore,an experiment was conducted to test the hypotheses that increasing dietary phytase after an 18-day adaptation period:1)increases nutrient and energy digestibility;2)increases plasma P,plasma inositol,and bone ash of young pigs;and 3)demonstrates that maximum phytate degradation requires more phytase than maximum P digestibility.Results Data indicated that increasing inclusion of phytase[0,250,500,1,000,2,000,and 4,000 phytase units(FTU)/kg feed]in corn-soybean meal-based diets increased apparent ileal digestibility(AID)of Trp(quadratic;P<0.05),and of Lys and Thr(linear;P<0.05),and tended to increase AID of Met(linear;P<0.10).Increasing dietary phytase also increased AID and apparent total tract digestibility(ATTD)of Ca and P(quadratic;P<0.05)and increased ATTD of K and Na(linear;P<0.05),but phytase did not influence the ATTD of Mg or gross energy.Concentrations of plasma P and bone ash increased(quadratic;P<0.05),and plasma inositol also increased(linear;P<0.05)with increasing inclusion of phytase.Reduced concentrations of inositol phosphate(IP)6 and IP5(quadratic;P<0.05),reduced IP4 and IP3(linear;P<0.05),but increased inositol concentrations(linear;P<0.05)were observed in ileal digesta as dietary phytase increased.The ATTD of P was maximized if at least 1,200 FTU/kg were used,whereas more than 4,000 FTU/kg were needed to maximize inositol release.Conclusions Increasing dietary levels of phytase after an 18-day adaptation period increased phytate and IP ester degradation and inositol release in the small intestine.Consequently,increasing dietary phytase resulted in improved digestibility of Ca,P,K,Na,and the first 4 limiting amino acids,and in increased concentrations of bone ash and plasma P and inositol.In a corn-soybean meal diet,maximum inositol release requires approximately 3,200 FTU/kg more phytase than that required for maximum P digestibility.
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.
