IMPACT OF A BALANCED AMINO ACID PROFILE ON BROILER PERFORMANCE

Summary. Three trials have been conducted to evaluate the application of the concept of the "Ideal Protein" (IP) in broiler diets. Two dose-response experiments with male broilers were conducted to study the effect of graded dietary amino acid (AA) levels on performance. The objective of the third experiment evaluated interactions between balanced dietary amino acid level and grow out period. According to the IP concept the ratios between the essential AA and lysine were identical in all diets within an experiment. Data revealed that current broiler breeds have a high performance potential which could be realised by optimising the AA supply of the birds. Even IP levels higher than 140% of current recommendation increased performance. However, especially amino acid supply during the early live showed the strongest impact on the performance in subsequent phases and therefore on final performance. Higher supply with balanced amino acids compared to current recommendation during the starter phase might be meaningful to ensure high performance and profitability. Keywords: Broiler, Amino acid requirement, Ideal protein, dose-response trial SUBALANSUOTŲ AMINO RŪGSCIŲ ĮTAKA BROILERIŲ PRODUKCIJOS GAMYBOJE Santrauka "Idealiojo proteino (IP)" broilerių racionuose koncepcijai įvertinti atlikti trys bandymai. Du bandymai atlikti su broileriais gaidiukais ir nustatytas tam tikrų papildomų dozių poveikis. Sių bandymų tikslas − istirti ribojamųjų amino rūgscių įtaką broilerių augimui. Treciojo bandymo tikslas − patikrinti rysį tarp subalansuotų amino rūgscių kiekio pasaruose ir augimo periodo. Laikantis IP koncepcijos, nepakeiciamųjų amino rūgscių ir lizino santykis visuose eksperimento racionuose buvo pastovus. Eksperimento duomenys rodo, kad galima padidinti ir taip didelį dabartinių broilerių rūsių potencialą, optimizavus amino rūgscių kiekį paukscių racione. IP kiekį padidinus net iki 140 %, palyginti su dabar rekomenduojamu, broileriai augo geriau. Didiausią įtaką broilerių augimui (kartu ir visose vėlesnėse augimo fazėse) turėjo pradinėje broilerių augimo fazėje pateiktas amino rūgscių kiekis. Didesnis negu dabar rekomenduojamas subalansuotų amino rūgscių kiekis pradinėje broilerių augimo fazėje (startinis) gali būti reiksmingas, siekiant geresnių augimo rezultatų ir didesnio pelno. Raktaodiai: broileris, amino rūgstys, amino rūgscių poreikis, idealusis proteinas, dozės veiksmingumo bandymas. Introduction. Genetic potential of current broiler breeds has been improved considerably during recent years. Apart from weight gain and feed conversion ratio breeder companies focus more and more on breast meat yield. It is well known that these performance criteria - especially breast meat yield - respond sensitively to suboptimum amino acid supply. However, increasing performance potential likely leads to changes in nutrient and thus amino acid requirement. On the other hand the development of the "Ideal Protein" concept has been an important progress on the animal nutrition side. This concept suggests that the ratios between the essential amino acids and lysine (as reference amino acid) are almost not influenced while the quantitative amino acid requirement is affected by many factors. The aim of the present experiments was to examine the response of modern broiler types to increasing levels of dietary protein which is balanced according to the "Ideal Protein" concept. Two trials were conducted to study the effects of graded levels of an ideal protein on various performance criteria during one single grow out phase ( grower /