Muscle protein degradation assessed by N-methylhistidine excretion in mature White Leghorn, dwarf broiler and normal broiler males maintained on either low- or high-protein diets (original) (raw)
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Comparative Biochemistry and Physiology Part A: Physiology, 1988
Abe&act-l. Growth of breast and leg muscles and excretion of N'methyl histidine in layer (slow growing) and broiler (fast growing) chicks were measured at five time intervals between 2 and 33 days of age. 2. The results indicate that muscles of the broiler chick grow faster than in layer chicks and that breast muscles of both strains grow faster than leg muscles in the first 2 weeks after hatching. 3. N'methyl histidine excretion by layer chicks is higher than that by broilers relative to body weight, musculature and relative maturity at all ages examined. 4. The results suggest that faster growth of muscles is accompanied by a lower rate of protein degradation although at ages of less than 2 weeks differences in protein synthesis rates may also contribute to muscle growth.
Revista Brasileira de Zootecnia
This study evaluated the effects of two protein levels and types of formulation on performance, nutrient metabolization, and myopathies of 390 female broilers from 21 to 46 days old distributed in a completely randomized design, with five treatments and six replicates of 13 broilers each. Treatments were two levels of protein (19.0 and 21.0%) in diets using only commercially available ingredients and three experimental formulations designed to keep similar the main nutrients that could influence nutritional performance (starch, fiber, ether extract), using unusual ingredients, with 19.0% (19E) or 21.0% (21E) crude protein and the third with 19.0% crude protein with amino acid levels similar to treatment 21P (19E+Aa). We studied broiler performance, nutrient digestibility, macroscopic muscular evaluation, and histological muscular evaluation. The design for the performance and myopathy assessment was a 5 × 2 factorial scheme, five diets × two ages (38 or 46 days). The worst feed conversion ratio was observed for the 19P treatment. Neither diet nor age had an effect on myopathies, however, older slaughter age increased the intensity of microscopic lesions. The diet 19P should be avoided and increased inclusion of lipids in diets improves nutrient utilization and, consequently, performance.
Growth and muscle protein turnover in the chick
The Biochemical journal, 1978
The growth rates of young chicks were varied from 0 to 10% per day by manipulation of the adequacy of the amino acid and energy supply. The rates of protein synthesis in the white breast (pectoralis thoracica) muscle and the dark leg (gastrocnemius and peronaeus longus) muscles were estimated by feeding l-[U-(14)C]tyrosine in amino acid/agar-gel diets (;dietary infusion'). This treatment rapidly and consistently produced an isotopic equilibrium in the expired CO(2) and in the free tyrosine of plasma and the muscles. Wholebody protein synthesis in 2-week-old chicks was estimated from the tyrosine flux and was 6.4g/day per 100g body wt. In 1-week-old chicks the rate of protein synthesis was more rapid in the breast muscles than in the leg muscles, but decreased until the rates were similar in 2-week-old birds. Synthesis was also more rapid in fast-growing Rock Cornish broilers than in medium-slow-growing New HampshirexSingle Comb White Leghorn chicks. No or barely significant decr...
Nτ-methyl histidine excretion by poultry: Not all species excrete Nτ-methyl histidine quantitatively
British Journal of Nutrition, 1983
1. The rate of elimination of administered Nτ-[14CH3]methyl histidine was used to assess the validity of Nτ-methyl histidine excretion as an index of muscle protein breakdown in poultry.2. Broiler chicks (2–3 and 4–5 weeks old), laying hens, adult quail (Coturnix coturnix japonica), adult cockerels and turkey poults (2–4 weeks old) were tested.3. All except the turkey poults showed quantitative recoveries of Nτ-[14CH3]methyl histidine within 1 week.4. Turkeys showed a different pattern of Nτ-[14CH3]methyl histidine output; the mean total recovery after 14 d was less than 50% of the injected dose. The majority of the label remaining after this time was found in breast muscle.5. All birds tested excreted Nτ-methyl histidine unchanged, although a small amount sometimes appeared as another metabolite.6. No significant oxidation of Nτ-[14CH3]methyl histidine by broiler chicks, turkey poults or adult quail was found.7. The results show that excretion of Nτ-methyl histidine is a useful mea...
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.
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...
African journal of agricultural research
An experiment was conducted to evaluate crude protein level on lysine requirements and performance of male broiler chickens. From 21 to 42 day old chicks were fed one combination of dietary lysine and CP (18, 20 and 22% crude protein and 0.08, 0.9, 1 and 1.1% lysine) in a diet containing 3.200 kcal/kg ME. Variables measured consisted of feed intake, body weight gain, feed conversion ratio, percentage of fat pad carcass, breast and thigh weight. The lysine requirement was estimated by broken line methodology based on body weight gain, feed conversion ratio, carcass and breast weight recorded in the grower period. There were significant effects of crude protein level on body weight gain, feed intake, feed conversion ratio and percentage of fat pad that existed. The body weight gain and feed intake increased and percentage of fat pad decreased as crude protein increased in the diet. However, increasing lysine in the diets significantly increased body weight gain, breast meat, thigh and...
Animal Science, 1997
An experiment was carried out to study the effect of changes in either the quality or the quantity of dietary protein intake on the free essential amino acid profiles in plasma, muscle or liver of growing chickens. Following a randomized paired-feeding design based on metabolic body weight (kg M0·75), White Rock male broilers were allocated to one of three isoenergetic (14·5 kJ metabolizable energy per g dry matter (DM)) semisynthetic diets containing different levels of protein (60, 120, 180 or 240 g/kg DM). All diets were based on soya-bean meal, as the sole source of protein, either unsupplemented (diets S) or supplemented with 20 g/kg L-lysine (diets SL) or 2 g/kg DL-methionine (diets SM). Samples of blood, biceps muscle and liver were taken and amino acid analysis was determined by high performance liquid chromatography. Plasma was only adequate to detect the effect of the supplementation with methionine to balance the dietary amino acid (AA) profile. Plasma concentrations of f...