Effects of digestible amino acid based formulation of low protein broiler diets supplemented with valine, isoleucine and arginine on performance and protein efficiency

The aim of the present study was to investigate the effect of digestible amino acid (DAA) based formulation strategy, and l-valine (l-Val), l-isoleucine (l-Ile) and l-arginine (l-Arg) supplementation to reduce the crude protein (CP) level of broiler diets on performance, carcass characteristics and protein efficiency ratio by comparing with the control diet formulated on total amino acid base. A total of 792 one-day-old Ross 308 broiler chicks were divided into 48 floor pens, with 24 pens containing 16 chicks and 24 pens containing 17 chicks. The experiment was organized in a completely randomized block design with four dietary treatments as follows; T1: formulated to meet minimum both total amino acid and DAA requirements without using l-Val, l-Ile, and l-Arg, T2: formulated to meet DAA requirements without using l-Val, l-Ile and l-Arg, T3: formulated to meet DAA requirements by using l-Val alone, T4: formulated to meet DAA requirements by using l-Val, l-Arg, and l-Ile. Each treatment had 12 replicates. Neither l-Val (T3) nor l-Val, l-Ile, and l-Arg supplemented (T4) low CP dietary treatments had any negative impact on growth performance, feed conversion ratio during experimental periods, as well as carcass parameters of broilers. Indeed, CP reduction by the addition of l-Val alone or l-Val, l-Ile, and l-Arg together even resulted in a significant improvement in protein efficiency ratio compared to T1 and T2 treatments. Supplementation of l-Val either alone or along with l-Ile and l-Arg to diets formulated based on DAA not only decreased dietary CP but also soybean meal inclusion. It can be concluded that maintained growth performance, and even improved protein utilization can be achieved due to the DAA based formulation strategy and supplementing broiler diets with l-Val alone or together with l-Ile and l-Arg.