Effect of decreasing dietary protein levels with optimum amino acids profile on the performance of broilers

Pakistan Veterinary Journal (Impact Factor: 1.39). 01/2004; 24.
Source: DOAJ


A six-week trial was conducted to study the effect of decreasing dietary crude protein (CP) level on the performance of broilers in hot climatic conditions. Four experimental rations having CP 23 (control group), 22, 21 and 20%, with optimal amino acid balance were prepared. All the four rations were isocaloric having ME 3200 kcal/kg with Energy: Protein (E:P) 139.0, 146.5, 152.4 and 160 in diets A, B, C and D respectively. One hundred and twenty day-old chicks were randomly distributed into 12 experimental units, each having 10 chicks. Rations were randomly allotted to experimental units such that each unit received three replicates. The experimental diets were fed to birds from day 1st to 42nd. Performance of birds was monitored in terms of weight gain, feed consumption and feed conversion ratio (FCR). At the end of experiment, two birds per each replicate were randomly selected and slaughtered to record the data on carcass yield, breast meat yield, abdominal fat and composition of breast meat. Results of the trial suggested that weight gain was significantly (P<0.01) increased in birds on diets with CP 20 and 21%. Feed consumption and FCR remained un-changed for all the treatment groups. Eviscerated carcass yield was significantly (P<0.05) higher for the group fed on diet with 20% CP. Breast meat yield, abdominal fat and composition of breast meat also remained un-changed. Economic evaluation of the trial revealed that decreasing CP levels from 23 to 20% resulted in reduced feed cost per kg of live weight gain, which clearly indicated that this approach was useful especially in severe summer conditions. The overall picture of the study suggests that dietary protein level of broilers could be reduced from 23 to 20%, with beneficial effects on growth performance and carcass characteristics and increased economic returns in hot environmental conditions, provided that levels of essential amino acids are closely looked after.

Download full-text


Available from: Zahid Kamran, Jan 26, 2014
  • Source
    • "Energy is offered for body function, and high energy diets result in extra deposition of fat pointing the wastage of dietary energy (Holsheimer and Jensen, 1991). Protein is an essential constituent of all tissues of body, and that having major effect on growth performance of the broilers is the most expensive nutrient in chicken diets (Kamran et al., 2004). However, the study of quality restriction synchronously including energy and protein has few been reported. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This experiment aimed to investigate the effects of early dietary energy and protein dilution on growth performance, nutrient utilization and internal organs of broilers. Of Arbor Acres, 1200 day-old male chicks were selected and randomly distributed to 16 experimental groups with factorial arrangement (4×4) including 4 levels of energy dilution and 4 of protein dilution (8 to 14 d of age). Birds were fed the same diets during the other period. Experiment of nutrient utilization was carried out 11 to 14 d of age. At 14 d, 1 bird/pen was slaughtered to determine internal organs. From 8 to 14 d, average daily feed intake (ADFI) of treatments protein diluted 10% was significantly less than of treatments protein diluted 20% (P<0.05). Feed conversion ratio (FCR) of treatments protein diluted 30% and energy diluted 15% was significantly less than other treatments (P<0.05). From 15 to 42 d, ADFI of treatments protein diluted 20% was significantly less than of treatments protein diluted 0 and 10% (P<0.05). At 42 d, body weight (BW) of treatments energy diluted 10% was more than of treatments energy diluted 0 and 15% (P<0.05). The FCR of treatments protein diluted 20% was significantly less than of treatments protein diluted 0 and 10%, and that of treatments energy diluted 15% was significantly more than other treatments (P<0.05). Data indicated that early dietary energy and protein dilution affected BW, ADFI and FCR, and the optimum treatment was 10% of dietary energy and protein dilution from 8 to 14 d.
    Italian Journal of Animal Science 05/2015; 14(2). DOI:10.4081/ijas.2015.3729 · 0.72 Impact Factor
  • Source
    • "As expected the optimal levels of protein, ME and AAs resulted in nonsignificant results of dressing percentage and breast and abdominal fat weight. Kamran et al. (2004) also reported unaltered results of carcass yield, breast meat yield and abdominal fat percentage in broilers fed on low protein diets supplemented with optimal levels of AAs. Previous studies (Holsheimer and Ruesink, 1993; Griffiths et al., 1977: Waldroup et al., 1991; Si et al., 2001) also showed similar findings of fat percentage in breast and leg muscles of broilers. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of present study was to investigate the effect of constant ratio between CP and ME at different levels of both nutrients on growth performance and meat characteristics of broilers form 1-28 days of age. One hundred and fifty day-old broiler chicks were divided into five units with 10 chicks in each unit. Each unit was fed on separate experimental diets form 1-28 days of age. Five starter rations were formulated in such a way to differ in CP (19.3%, 20.2%, 21.2%, 22.1% and 23.0%) and ME (2771, 2837, 2963, 3090 and 3216 Kcal/Kg of diet) but all have constant CP: ME (which was 1:140). At the end of trial, growth performance and meat characteristics data were collected. The results of feed consumption and feed conversion ratio showed significant (P<0.05) difference in five units fed on five experimental diets separately while weight gain remained unaffected (P>0.05). In addition, meat characteristics did not change by changing CP or ME levels (P>0.05). The results of present concluded that feed consumption decreased while FCR improve as the diet nutrient density increased. However, it is concluded form present study that in broiler starter period (1-28 days) CP and ME can lowered up to 19.3% and 2771 Kcal/Kg of diet respectively, without impairing performance of broiler.
  • Source
    • "It is common practice in the poultry industry to provide varying diets during the growing period. Protein is an essential constituent of all tissues of animal body and has major effect on growth performance of the bird [2]. A better understanding of the nutritional requirements of amino acids allows a more precise nutrition, offering the possibility for the formulator to optimize the requirement of at least minimum levels of crude protein by essential amino acids requirements, generating better result and lower costs for the producer [3]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Four experiments were conducted, in two stages, to evaluate protein and limiting amino acids' (lysine and methionine + cystine) levels in pre-starter diets on broilers' performance. In each experiment of Stage 1, 640 new-born male Ross 308 cockerels were randomly allocated to eight dietary treatments with a 2 × 4 factorial arrangement. In experiment 1-1, two levels of crude protein (CP: 21% and 23.2%) and four levels of Lys (1.2, 1.3, 1.4, and 1.5%) and in experiment 1-2, two levels of CP (21 and 23.2%) and four levels of Met + Cys (0.85, 0.90, 0.95, and 1.00%) were used. In Stage 2, the optimum levels of Lys and Met + Cys obtained from Stage 1 (1.3 and 1.5% Lys, 0.90 and 1.00% Met + Cys in experiment 1-1 and 1-2, resp.) with two levels of CP (21 and 23.2%) were used in two separate simultaneous experiments with a 2 × 2 factorial arrangement for male and female birds. The levels of CP significantly influenced BWG and FCR in experiment 1-1. Dietary levels of Lys affect BWG (experiment 1-1) and FI (experiments 1-1 and 2-1) significantly. In experiments 1-2 and 2-2, the different levels of Met + Cys did not affect BWG, FI, and FCR of male or female broilers. The results of these experiments indicated that the optimal level of dietary protein and Lys were 23.2% and 1.5%, respectively. Diets with 1% Met + Cys caused optimal performance.
    Veterinary Medicine International 09/2012; 2012:394189. DOI:10.1155/2012/394189
Show more