Carcass, Organs and Economic Evaluation of Broiler Birds Fed Low-protein Diets Supplemented with the Most Limiting Essential Amino Acids in Ideal Protein Concept

This study evaluated the carcass, organs and economic parameters of broiler birds on the 57th day of production considered to be the economic market weight in which ideal protein concept was tested using the most limiting essential amino acids (EAAs), L-Lysine, DL-Methionine, L-Tryptophan and L-Threonine as supplements in low crude protein diets. Two sets of experimental diets were prepared for the two phases of broiler production at broiler starter (BS) and broiler finisher (BF) phases. At the BS phase (0-28 days), crude protein levels were varied from 23.0% in both the control diet (conventional BS diet with plant protein origin and fish meal) and diet 2 with the most limiting EAAs to diet 6 with the lowest crude protein of 11.0%. At the BF phase (29-57 days), six dietary treatments in which crude protein varied from 20.0% to 8.0% were used. The average live weight (LW) of 2490.3±25.2g obtained for birds on diet 3 (17.0% CP with EAAs supplementation) was the highest but similar (P>0.05) to the LW values of 2378.3 ± 24.6g, 2370.0 ± 47.9g and 2267.0 ± 53.0g obtained for birds on diets 4 (14.0% CP with EAAs supplementation), diet 2 (20.0% CP with EAAs supplementation) and the control diet 1 (20.0% CP conventional diet with some protein of animal origin), respectively. The average slaughtered weight of 2425.0±19.4g was also the highest value for birds on diet 3 (17.0% CP with EAAs supplementation). The average carcass weight value of 1798.3±21.8g was the highest and obtained for birds on diet 3 (17.0% CP with EAAs supplementation). There were similarities (P>0.05) among weights of most organs investigated. Data obtained were analysed statistically using Minitab (Version 16).

The total net return/bird (gross profit) was highest at N792.06 for birds on 20.0%/17.0% CP for broiler starter/finisher EAAs supplemented diets, respectively. Noteworthy that birds on diet 4 (17.0%/14.0% CP for broiler starter/finisher EAAs supplemented diets, respectively diets with EAA supplementation) had better net returns (gross profit) over the control diet formulated conventionally to contain 23.0%/20.0% CP for broiler starter/finisher diets at minimum Lys & Met supplementation.