Ideal Amino Acid Pattern For Laying Hens At The Stage Of Egg-laying Peak

The experiment was conducted todetermine the standardized ilealdigestibilities of aminoacids and the requirements of amino acids,and set up theideal pattern of the amino acids forlaying hens of30～38w of age.It can improve the availability ofamino acids and offer thebasis to establish the requirements of amino acids for ducks and toutilize the resource ofprotein feed efficiently.Two trials were conducted in my study.Trial1was conducted to determin the standardized ilealamino aciddigestibility offeedstuffsinroosters.Fourty-eight30-week-old roosters were housed in dividual cages.Twelve roosters wereusedto determine theendogenous flows of amino acid at the terminal ileum, and the otherthirty-six roosters were used to determine thestandardized ileal digestibility of the amino acidin the corn, soybean and feather meals.The results of the standardized ileal digestibility of theamino acidsin corn meals wereas follows: Asp82.74%, Thr83.75%, Ser82.10%, Glu92.81%,Gly81.20%, Ala90.11%, Cys81.90%, Val90.42%, Met94.00%, Ile86.19%, Leu90.42%,Tyr88.78%, Phe89.24%, His94.43%, Lys90.58%, Arg93.15%, Pro85.67%andTrp83.36%,respectively, the standardized ileal amino acid digestibility of soybean mealswereas follows:Asp86.16%, Thr87.10%, Ser87.98%, Glu91.67%, Gly88.32%, Ala88.49%,Cys84.53%, Val88.98%, Met90.20%, Ile87.78%, Leu87.16%, Tyr89.36%, Phe88.21%,His88.64%, Lys90.14%, Arg93.98%, Pro86.53%and Trp95.18%,respectively,and thestandardized ileal amino acid digestibility of feather mealswereas follows:Asp47.07%, Thr53.28%, Ser61.00%, Glu57.84%, Gly62.58%, Ala71.73%, Cys47.22%, Val50.55%, Met53.79%, Ile66.18%, Leu67.76%, Tyr60.36%, Phe69.31%, His58.89%, Lys57.00%, Arg67.60%, Pro56.73%and Trp55.30%,respectively.The results showed thatthe apparent ilealdigestibilities ofMet and Leu in the soybean meal were lower than those in the corn,otherwhile, the apparent ileal digestibilities of the other all amino acids in the soybean werehigher than in the corn and the feather meal,and the standardized ileal digetibilities of theamino acids in the soybean meal were higher than both in the corn and in the feather meal,except for the standardized ileal digetibilities of Glu, Ala, Val, Met, Leu, Phe, His, and Lys inthe corn were higher than in the soybean meal and feather meal. Trial2:Four separate experiments were conducted to study the requirements andideal ratios of Lys, Met, Trp and Thr for laying hens of30-38w of Age.Three hundred and sixty Hy-Line laying hens were randomly divided into five dietarytreatments with six replicates per group and12laying hens per replicate. Crystalline aminoacids were added to basal diet to yield5graded inclusions of the assayed amino acid. Henswere fed the assay diets for10weeks, with the first2wk considered a depletion period.Theresults showed that the responses to intake of SIDLys, Met, Trp and Thr fitted one-slopebroken-lines well and the regression equations based on egg mass were as follows:Y=51.60-0.0416(682.5-x)(,R~2=0.96);Y=51.43-0.085(314.1-x)(,R~2=0.95);Y=51.17-0.1554(163.0-x),(R~2=0.97);Y=52.85-0.0576(499.5-x),(R~2=0.93).The results showed that theSID amino acid requirements for Hy-Line laying hens of30-38w of age for maximum eggmass were684mg/d of Lys,313mg/d of Met,171mg/d of Trp,506mg/d of Thr.The idealamino acid ratio for Hy-Line laying hens of30-38w of age for maximum egg mass wasLys:Met:Trp:Thr=100:46:24:73.