Effects of dietary amino acid levels and ambient temperature on mixed muscle protein turnover in Pectoralis major during finisher feeding period in two broiler lines (original) (raw)
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International Journal of Poultry Science, 2007
Heat stress causes significant economic losses on broilers production due to poorer performance and carcass quality. Considering that protein has the highest heat increment among nutrients, it has been suggested that protein levels should be reduced in diets for heat-exposed broilers. Nevertheless, there are no conclusive results on the benefits of such practice, and further studies should be performed to elucidate some reported discrepancies. Thus, a trial was carried out to evaluate the effects of dietary protein levels (17, 20 and 23%) and environmental temperature (22 and 32ºC) on the performance, nutrients digestibility, and energy and protein metabolism of broiler chickens from 21 to 42 days of age. Nutrients digestibility was determined by total excreta collection, and energy and protein metabolism was evaluated by comparative slaughter method. It was concluded that (1) heat exposure impairs broilers performance and increases nitrogen excretion, but do not change nutrients digestibility; (2) high-protein diets are technically feasible and promotes lower heat production for broilers reared under thermoneutral or hot environments, however, highprotein diets increases nitrogen excretion.
Effect of varying dietary energy and protein on broiler performance in hot climate
Animal Feed Science and Technology, 2008
The experiment was conducted to evaluate the effect of varying dietary metabolizable energy (ME) and crude protein (CP) concentrations on broiler performance during hot summer conditions. One day old straight-run (0.50 male and 0.50 female) Starbro broiler chicks (n = 600) were randomly divided into 30 experimental units of 20 chicks each. Two levels of dietary ME (12.13 and 12.55 MJ/kg) and three levels of dietary CP (190, 210 and 230 g/kg) were used in a 2 × 3 factorial arrangement giving six dietary treatments. Level of essential amino acids were maintained in all the diets by supplementing low CP diets with crystalline amino acids. Each of the experimental diets was offered to five replicates from hatching to 28 d of age. At the end of the experiment, two birds from each replicate were randomly selected for data on dressing yield, breast meat yield, abdominal fat, and liver and gizzard weights. Increasing dietary ME significantly increased the BW gain, abdominal fat and liver weights, and protein and fat contents of the carcass whereas the dry matter of carcass was reduced by increasing dietary ME. Dietary CP had quadratic effects on BW gain, F:G, carcass weight, and dry matter and protein contents of the meat. Breast weight and fat contents of meat increased linearly with increasing CP of the diets. The low CP diets (i.e., 190 g/kg) at high ME (i.e., 12.55 MJ/kg) increased * Corresponding author at: et al. / Animal Feed Science and Technology 146 (2008) 302-312 303 the BW gain, feed intake, carcass weight and improved F:G. However, lowest F:G was observed in birds fed 210 g CP and 12.13 MJ ME/kg of diet. Protein and fat contents of the carcass were increased in birds fed on diets having high CP and ME whereas dry matter contents of meat improved with high CP and low ME diets. The results of the trial showed a correlation between dietary CP and ME and hence the optimal value for one cannot be predicted without considering the other. Briefly, low CP with high ME diets improved the overall performance when environmental temperature ranged from 32 to 39 • C.
Animals
The objective of this study was to evaluate the effect of low-protein diets with amino acid supplementation on growth performance, carcass yield, meat quality and nitrogen excretion of broilers raised under hot climate conditions during the finisher period. In trial 1, broilers from 28 to 49 days of age were fed 18% crude protein (CP) as a positive control or 15% CP supplemented with (1) DL-methionine (Met) + L-lysine (Lys), (2) Met + Lys + L-Arginine (Arg), or (3) Met + Lys + L-Valine (Val). In trial 2, broilers from 30 to 45 days of age, were fed an 18% CP diet as a positive control or 15% CP supplemented with Met, Lys, Arg, Val, L-Isoleucine (Ile) or combination with glycine (Gly) and/or urea as nitrogen sources: (1) Met + Lys, (2) Met + Lys + Arg, (3) Met + Lys + Val, (4) Met + Lys + Ile, (5) Met + Lys + Arg +Val + Ile + Gly, and (6) Met+ Lys + Arg + Val + Ile + Gly + urea. Protein use was improved by feeding low-protein amino acid-supplemented diets as compared to the high-prot...
Increased dietary balanced protein levels at varying length of application in 1-14 days old broilers
In the present trial increasing levels of balanced protein (BP; 100 (control), 115, 130, 145, 160% of recommendation) were fed from day one either for two, four, eight, or twelve days to male broilers (control + 4 x 4). After feeding the experimental diets dietary BP was reduced to the control level. This was done in two steps (2-day transition period) in order to avoid too strong changes in amino acid supply. Increasing BP levels non-linearly improved weight gain and feed conversion. This effect was most pronounced when experimental diets were fed for 12 days (p<0.05). Feeding increasing BP levels for two or four days had no effects on weight gain and feed conversion ratio. On day 14 two birds per pen were selected for dissection. Weights of the empty small intestine were determined. Enhancing the length of feeding the experimental diets from 2 to 12 days significantly increased the relative weight of the duodenum and jejunum (% of body weight) whilst dietary BP had no effect. H...
2012
The effect of amino acids (AAs) supplementations on improving utilization of protein and decreasing nitrogen excretion was studied with Arbor Acres broiler males during days 1-28 of age (Trial 1) and 1-21 of age (Trial 2). In trial 1, the positive control (PC) diet contained 23% CP while PC in trial 2 was 22% CP. In trial 1, the negative control (NC) diet contained 18% CP supplemented with methionine (Met) plus lysine (Lys) as that of the PC. The NC was supplemented or not with arginine (Arg), therionine (Thr), valine (Val), isoleucine (Ile) or all of these amino acids (AA) according to NRC (1994). In addition, glycine was supplemented to the later treatment as amino nitrogen. In trial 2, the NC diet contained 19% CP diet was formulated based either on corn-soybean meal without (vegetable diet) or with fish and meat meals (animal protein diet). The NC diet was supplemented or not with Arg, Thr, Val, tryptophan (Tryp) or a combination of all of these AA plus isoleucine (Ile) to meet ...
Journal of The Science of Food and Agriculture, 2007
The need for a critical amino acid (AA) profile for growth, immune response and N utilisation of naked neck broilers during summer was studied. Day-old naked neck chicks (n = 198) from a single hatch were distributed into 24 groups (four dietary regimens (DRs) with six replicates each) having eight birds in each replicate. The first diet was based on crude protein (CP) and metabolisable energy (ME) (13.40 MJ) as per NRC recommendations (DR1). In the second diet, the CP content was reduced through supplementation of synthetic AAs to achieve critical AA contents as suggested by NRC with 13.40 MJ ME (DR2). In the third diet critical AAs were supplemented to achieve their level at 108% of NRC with 12.6 MJ ME (DR3), while in fourth diet critical AA concentration was reduced to 94% (DR4) of NRC with 12.6 MJ ME to match the ratio of ME to AA concentration as that of NRC (1994). Diets were formulated separately for starter (0–3 weeks) and finisher (3-6 weeks) phases. A metabolism trial was conducted at the third week of age. At 3 and 6 weeks of age eight birds (four of each sex) per treatment were killed to study the growth of immune organs (Bursa of Fabricius, thymus and spleen). Immune response was studied at the fourth week of age. During the starting phase, the birds fed DR1 and DR2 having 13.40 MJ ME kg−1 diet had higher body weight (P < 0.044) gain (P < 0.048) and better feed conversion ratio (FCR) (P < 0.001) as compared to DR3 and DR4 (12.6 MJ ME kg−1 diets). However, better (P < 0.001) CP efficiency (CP intake kg−1 gain) and lower feed cost kg−1 gain (P < 0.001) was recorded in DR4. A similar trend was also observed during the finisher phase. Dietary regimens had no effect on dry matter (DM) metabolisability, N intake or output and N retention. There was no difference in the weight of immune organs (bursa, thymus and spleen) between dietary treatments at either 3 or 6 weeks of age. The cell mediated and humoral immune response was also not different between the NRC and modified NRC levels. Copyright © 2007 Society of Chemical Industry
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Animal Science and Biotechnologies, 2013
The aim of study was to evaluate the effects of three dietary protein levels on body composition, plasma metabolic profile and litter composition of broilers at 42 days of age. One-day-old unsexed Cobb 500 broilers (n=600) were randomly assigned in 3 groups with 4 replications per treatment. Three diets were formulated for each growth phases, to contain 3 levels of protein: high protein (HP), medium protein (MP) and low protein (LP). The diets were isocaloric, with similar content of digestible sulphur amino acids, lysine, calcium and available phosphorus. The empty body weight (BW) of broilers was influenced by the dietary treatments (+ 8% in HP, respectively - 7.7% in LP vs. MP; P 0.05). In general, plasma biochemical parameters were not influenced by the dietary protein levels (P>0.05). In conclusion, low protein diets can support similar quality performance that high or medium diets when the quality ingredients are used. The lower dietary protein level resulted in reduced nit...
Effect of Metabolic Excesses from Dietary Proteins on Blood Profile of Heat-stressed Broilers
2021
Although, dietary proteins play a crucial role in poultry profit maximization, through the sustenance of birds` welfare, growth and development, yet metabolic excesses from crude protein (CP) degradation is detrimental to broiler chickens (BC) affected by heat stress. This study evaluated the effect of dietary protein levels on blood profile of heatstressed BC at starter phase (SP) and finisher phase (FP). Arbor Acre BC (n=288) were randomly allotted to four dietary treatments (T1- 23% CP; T2- 21% CP; T3- 19% CP; and T4- 17% CP) with six replicate groups in a completely randomized design. Data were subjected to descriptive analysis, analysis of variance (p=0.05) and correlation statistics. Protein intake (PI) was not significantly affected by varying CP in diets at SP, but not at FP, where PI significantly increased with increasing dietary CP. PER had a negative correlation with PCV (r= -0.89, p<0.01), Hb (r= -0.88, p<0.01), RBC (r= -0.93, p<0.01) and PI (r= -0.78, p<0.0...
International Journal of Poultry Science, 2004
In a 2×3 factorial arrangement, the effects of dietary protein and lysine levels on performance and carcass characteristics of Ross male broiler chickens from 1 to 3 weeks and 4 to 6 weeks of age were tested. Dietary treatments consisted of three levels of L-lysine.HCl in starter and grower period (0.0, 1.5 and 3.0 g/kg) and two levels of protein (208.4, 178.4 in starter and 181.2, 161.2 g/kg in grower period) with 12.12 MJ AME/kg diet. Reducing dietary protein decreased weight gain in starter, grower and total period up to 6.0, 4.6 and 5.6% respectively (P<0.05). It also decreased feed consumption in starter period (P<0.05). Decreasing dietary protein had no significant effect on gain to feed ratio and breast meat yield, but increased abdominal fat percentage significantly (P<0.05). Increasing dietary lysine increased feed consumption in starter and weight gain, feed to gain ratio in grower and total period of the experiment (P<0.05). It also increased breast meat yield and percentage (P<0.05). N excretion reduced significantly by decreasing dietary protein (P<0.05). Dietary treatments had no significant effect on mortality.
The Efficiency of Protein Utilization in Different Broiler Strains
Journal of the Indonesian Tropical Animal Agriculture, 2009
The objective of this work was to study the protein utilization and protein turnover of different broiler strains and was carried out in completely randomized design. One hundred and forty four sexed doc from each strain (Cobb =A, Ingham = B and Steggels = C) were divided into a factorial arrangement (three dietary protein, two sexes and three strains). Two regimens of composite mixes of a summit and dilution diet and a free choice between these two diets. Diets were changed weekly, with notional crude protein levels at one day-old of 240g/kg for all chickens, and at 42 days of age of 120 or 180 g/kg in the low and high protein. Protein utilization efficiency (PRE) was measured from 39-42 d of age. PRE increased with the increasing of dietary protein in strains A and C and had much higher response than in strain B. The moisture: protein ratios were 2.51, 2.65 and 2.58 in strains A, B and C, indicating strain B contained higher moisture and body fat and less protein. Involvement of genetic controls as the selection effect seems to increase the capacity of chickens in improving nutrient utilization.