Progress of amino acid nutrition for diet protein reduction in poultry

There is growing interest among nutritionists in feeding reduced protein diets to broiler chickens.Although nearly a century of research has been conducted providing biochemical insights on the impact of reduced protein diets for broilers,practical limitation still exists.The present review was written to provide insights on further reducing dietary protein in broilers.To construct this review,eighty-nine peer reviewed manuscripts in the area of amino acid nutrition in poultry were critiqued.Hence,nutritional research areas of low protein diets,threonine,glycine,valine,isoleucine,leucine,phenylalanine,histidine,and glutamine have been assessed and combined in this text,thus providing concepts into reduced protein diets for broilers.In addition,linkages between the cited work and least cost formation ingredient and nutrient matrix considerations are provided.In conclusion,practical applications in feeding reduced protein diets to broilers are advancing,but more work is warranted.

Dietary branched-chain amino acid assessment in broilers from 22 to 35 days of age

Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets.To evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the branched-chain amino acids(BCAA)are needed.A three level(−1,0,+1),three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65,75,and 85 for valine,58,66,and 74 for isoleucine,and 110,130,and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of age.Results:Live performance of male broilers was not affected by BCAA level.However,male broilers fed increasing isoleucine had improved(P=0.07)carcass yield as leucine and valine were reduced.Female broilers had improved body weight gain(P=0.05)and feed conversion(P=0.003)when leucine and isoleucine were at their lowest levels,independent of valine,but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore responses.Increasing dietary isoleucine and valine in female broilers increased breast meat yield(P=0.05),but increasing leucine tended to diminish the response.Conclusion:The female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than males.Specifically,as dietary leucine is increased in female broilers,dietary isoleucine increases were needed to offset the negative effects.Both increases in dietary valine and isoleucine improved breast meat yield in female broilers,but only when birds were fed the lowest dietary leucine.

日粮不同氨基酸水平对Ross与708杂交肉仔鸡的饲喂效果

选取1日龄Ross×708杂交肉仔鸡2592只，公母分开，地面平养，分为144个分区（每个处理组设12个重复），1～55日龄分别饲喂含高水平（H）或适宜水平（M）氨基酸的日粮。用回肠可消化氨基酸与赖氨酸的比率评价日粮。6个处理组日粮（MMMMM、HMMMM、HHMMM、HHHMM、HHHHM和HHHHH）分5个阶段（1～5d、6～14d、15～35d、36～45d和46～55d）饲喂。结果表明：公鸡的体重显著高于母鸡（P≤0．05），饲料转化、腹脂、胸肉产量均显著低于母鸡（P≤0．05）。饲喂H日粮的肉仔鸡，在前3个阶段其体重和饲料转化率达到最佳水平（P≤0．05），而且H日粮在全期的饲料转化率最佳（P≤0．05）。