The influence of phytase, pre-pellet cracked maize and dietary crude protein level on broiler performance via response surface methodology

Background:The reduction of crude protein levels in diets for broiler chickens may generate economic,environmental and flock welfare and health benefits;however,performance is usually compromised.Whole grain feeding and phytase may improve the utilization of reduced crude protein diets.Results:The effects of pre-pellet cracked maize(0,15%and 30%)and phytase(0,750 and 1500 FTU/kg)in isoenergetic maize-soy diets with three levels of crude protein(22%,19.5%and 17%)were evaluated via a BoxBehnken response surface design.Each of 13 dietary treatments were offered to 6 replicate cages(6 birds/cage)of male Ross 308 broiler chicks from 7 to 28 d post-hatch.Model prediction and response surface plots were generated from experimental data via polynomial regression in R and only significant coefficients were included and discussed in the predicted models.Weight gain,feed intake and FCR were all influenced by pre-pellet cracked maize,phytase and crude protein level,where crude protein level had the greatest influence.Consequently,the reduction from 22%to 17%dietary crude protein in non-supplemented diets reduced weight gain,feed intake,relative gizzard weight,relative gizzard content and relative pancreas weight but improved FCR.However,the inclusion of 30%cracked maize to 17%crude protein diets restored gizzard weight and 1500 FTU phytase inclusion to 17%crude protein diets increased relative gizzard contents and pancreas weights.Cracked maize and phytase inclusion in tandem to 17%crude protein diets increased weight gain,feed intake and FCR;however,this FCR was still more efficient than broilers offered the non-supplemented 22%crude protein diet.Broilers offered the prepellet cracked maize and phytase inclusions reduced AME in 22%crude protein diets but improved AME by 2.92 MJ(14.16 versus 11.24 MJ;P<0.001)in diets containing 17%crude protein.Ileal N digestibility was greater in broilers offered diets with 17%crude protein than those offered the 22%crude protein diet;irrespective of phytase and pre-pellet cracked maize.Conclusion:Pre-pellet cracked maize and phytase inclusions will improve the performance of broilers offered reduced crude protein diets.

最大化植酸酶性能

在动物营养中,钙在磷的利用上起着重要作用,这对肉鸡的生产性能来说至关重要。因此,优化可利用钙水平(相对于日粮中磷的含量)有助于改善日粮的利用率。最大限度发挥植酸酶的作用始于优化日粮中钙的水平。

Functionality of a next generation biosynthetic bacterial 6-phytase in enhancing phosphorus availability to weaned piglets fed a corn-soybean meal-based diet without added inorganic phosphate

The utility of a next generation biosynthetic bacterial 6-phytase(PhyG)in restoring bone ash,bone phosphorus(P)content and performance in piglets depleted in P was evaluated.A total of 9 treatments were tested as follows.Treatment 1,a negative control(NC)diet;treatments 2,3,4,NC supplemented with 250,500 or 1,000 FTU/kg of PhyG;treatments 5,6,NC supplemented with 500 or 1,000 FTU/kg of a commercial Buttiauxella sp phytase(PhyB);treatments 7,8,9,NC supplemented with monocalcium phosphate(MCP)to provide 0.7,1.4 and 1.8 g/kg digestible P,equating to a digestible P content of 1.8,2.5 and 2.9 g/kg.The latter constituting the positive control(PC)diet with adequate P and calcium(Ca).The NC was formulated without inorganic P(1.1 g digestible P/kg)and reduced in Ca(5.0 g/kg).Additional limestone was added to treatments 7 to 9 to maintain Ca-to-P ratio between 1.2 and 1.3.A total of 162 crossed Pietrain x(Large White×Landrace)21-d-old piglets(50%males and 50%females)were fed adaptation diets until 42 d old and then assigned to pens with 2 pigs/pen and 9 pens/treatment in a completely randomized block design.Piglets were fed mash diets based on corn and soybean meal ad libitum for 28 d.At the end of the study,one piglet perpen was euthanized and the right feet collected for determination of bone strength,bone ash and mineral content.Compared with the PC,the NC group had reduced average daily gain(ADG)and increased feed conversion ratio(FCR)during all growth phases and overall,and at d 28(70 d old)NC pigs had bones with reduced ash,Ca and P content(P<0.05).The PhyG at 250 FTU/kg improved bone ash vs.NC.Increasing PhyG dose linearly or quadratically improved bone ash,ADG and FCR(P<0.05).At>500 FTU/kg,both PhyG and PhyB maintained ADG and FCR equivalent to PC.Linear regression analysis was done to compare the measured response parameters to increasing digestible P from MCP.Based on this analysis it was shown that PhyG and PhyB at 1,000 FTU/kg could replace 1,83 and 1.66 g/kg digestible P from MCP in the diet,respectively,on average across metacarpi bone ash,ADG or FCR.These findings suggest that the biosynthetic phytase is highly effective in the tested dietary setting.

Corrigendum to “Functionality of a next generation biosynthetic bacterial 6-phytase in enhancing phosphorus availability to weaned piglets fed a corn-soybean meal-based diet without added inorganic phosphate” [Animal Nutrition 6/1 (2020) 24e30]

The authors regret that the following errors are found in the Materials and method under section 2.4.Chemical analysis.The following sentence:“Analysis of exogenous phytase activity in feeds was performed according to Engelen et al.(1994)”should instead to be corrected to:“Analysis of exogenous phytase activity in feeds was performed according to a modified version of the 2000.12 AOAC method(Engelen et al.,2001).”

Productive performance of commercial growing and finishing pigs supplemented with a Buttiauxella phytase as a total replacement of inorganic phosphate

The objective of this study was to test if a novel phytase from Buttiauxella sp. can replace all added inorganic phosphate in a diet with reduced Ca and metabolizable energy(ME) fed to commercial pigs from12 kg body weight(BW) until slaughter, whilst maintaining performance and carcass quality parameters.Four dietary treatments were tested in a completely randomized design with 9 replicate pens, each containing 31 mixed sex Newsham Choice pigs. Diets included a positive control(PC) based on corn,soybean meal, wheat middling and bakery meal, meeting all nutrient requirement of pigs; a negative control(NC) excluded inorganic phosphate and with reduced Ca(-0.13%) and ME(-0.15 MJ/kg); and NC supplemented with Buttiauxella phytase at 500 or 1,000 FTU/kg feed. Diets were fed ad libitum in mash form in 5 phases: starter(12 to 25 kg BW), grower 1(25 to 50 kg BW) and 2(50 to 75 kg BW), and finisher1(75 to 100 kg BW) and 2(100 kg BW to slaughter). The NC group showed lower(P < 0.05) average daily feed intake(ADFI) and average daily gain(ADG) in starter and grower phases, lower gain to feed ratio(G:F)in starter and grower 1 compared with PC. Pigs receiving the high dose of phytase of 1,000 FTU/kg had improved performance vs. the 500 FTU/kg phytase treatment in starter and grower 1 phase compared with the PC in grower 1 phase. Increasing phytase dose resulted in a linear increase in ADG(12 to120 kg BW) and G:F(50 to 75 kg BW). A comparison of treatment groups over the full production period from 12 kg BW until slaughter showed that both 500 and 1,000 FTU/kg phytase treatments were able to maintain growth performance and carcass characteristics compared with PC. The application of Buttiauxella phytase could therefore be used as an effective strategy to replace all inorganic phosphate in diets of pigs fed corn, soybean meal, wheat middling and bakery meal based diets from 12 kg BW. An economic analysis showed greater return from both phytase treatments vs. the PC and favored the higher phytase dose at 1,000 FTU/kg vs. the traditional dose of 500 FTU/kg. The latter was mainly related to the improved performance of the higher dose in younger pigs to 75 kg BW.