Conditions Affecting Plasma Amino Acid Patterns in Chickens Fed Practical and Purified Diets

Abstract

Experiments were conducted to investigate plasma free amino acid concentrations in the chick. After one hour of fasting, total plasma amino acid concentration decreased to approximately half of the full-fed value. Within three to six hours, most amino acids had returned toward the full-fed level but did not exceed it throughout a 48 hour period of starvation. However, after 48 hours fasting lysine, threonine, and isoleucine accumulated three-fold, two-fold and two-fold of the full-fed level, respectively. Serine and glutamic acid exceeded the full-fed level at three hours and then declined. Alanine reached its highest level after six hours of fasting and then declined. In full-fed chicks diurnal variations of plasma free amino acid concentrations were observed. The lowest and highest concentrations were observed at 11 a.m. and 8 to 11 p.m., respectively under a 24 hr-lighting. Reference plasma amino acid patterns are reported for chicks fed a practical diet ad libitum. In day-old chicks, concentrations of total amino acids, methionine plus one half cystine, lysine, and arginine were high. Alanine and glutamic acid concentrations were low. Most amino acid concentrations declined gradually during the first four weeks of life, but methionine plus one half cystine, phenylalaine, threonine and serine concentrations decreased sharply between two and four weeks. Lysine concentration continued to decrease in chicks fed the starter diet. At 20 weeks, plasma amino acid concentrations had decreased considerably except for methionine plus one half cystine and basic amino acids. The plasma amino acid pattern for chicks fed an isolated soybean protein diet was similar to that of chicks fed the practical diet.

Is methionine transaminated in skeletal muscle?

“…(60 d.p.m./#1), with or without the addition of BCAA or all amino acids other than methionine at plasma concentrations [8,15]. In all of these experiments, one muscle was used for the control while the contralateral muscle was used for the treatment.…”

The effect of ketone bodies on alanine and glutamine metabolism in isolated skeletal muscle from the fasted chick

“…In experiments designed to measure the amounts of alanine, glutamate, glutamine and tyrosine in the muscle proteins, in the intracellular free pool and released to the incubation media, EDC muscles were incubated in the basal medium containing 12 mM-glucose as described above. In experiments designed to determine the effect of pyruvate and ketone bodies on amino acid metabolism, the basal media contained 12 mM-glucose, 0.5 mMleucine, 0.5 mM-valine, and all other amino acids at plasma concentrations [26], except for alanine, glutamine, glutamate, tyrosine and histidine, which were absent (medium B). Medium B containing either 0 or 12 mMglucose was used in studies of the effect of glucose on amino acid metabolism.…”

Central Interaction Between L-Ornithine and Neuropeptide Y in the Regulation of Feeding Behavior of Neonatal Chicks

“…Consequently, this study further demonstrated that central NPY altered the utilization of metabolic fuels from carbohydrates to lipids/proteins. Therefore, the reduction in plasma amino acid concentrations observed in all NPY-treated groups in the present study was likely due to the accumulation of protein synthesis rather than to the gluconeogenic phenomenon observed in chicks during starvation ( Maruyama et al ., 1976 ). White et al .…”