High beta-hydroxybutyrate concentration in liver and skeletal muscle of newly hatched chicks

Characteristic changes in ketone body concentrations in blood, liver, and skeletal muscle were investigated in detail in newly hatched chicks. The concentration of beta-hydroxybutyrate in the blood was maximal at hatch (0 day), markedly decreased to 3 days, then maintained at low levels, up to 14 days of age. The concentration of acetoacetate in blood, on the other hand, did not change after hatching but remained lower than that of beta-hydroxybutyrate at all ages. In liver and muscles, the concentration of beta-hydroxybutyrate changed in a manner similar to that in the blood. The muscle to blood ratio of the beta-hydroxybutyrate concentration on days -1 and 0 was significantly higher than those at 1 through 14 days post-hatch. These results show that newly hatched chicks have the same high ketone body concentrations in the skeletal muscle, blood and liver. It is, hence, suggested that uptake of beta-hydroxybutyrate by muscles is substantial or that ketogenesis, if any, occurs in muscles immediately before and after hatching of chicks.     

Patterns of amino acid enzyme in domestic fowl breast and leg muscle during development

Activities of alanine and aspartate transaminases, glutamine synthetase, adenylate deaminase, glutamate and xanthine dehydrogenases and lactate dehydrogenase were measured in leg and breast muscles of developing chicks from day 10 in ovo to day 5 of free life, and compared with measurements for adult hens. Xanthine dehydrogenase activity was low in both muscles with adult levels attained on day 15 in ovo. Glutamine synthetase for chicks was maintained higher during development than for adults in both muscles. Minor differences were observed between both muscles in all enzymes tested up to day 18. With low embryonic values and important rises before hatching, the differences were initiated in the posthatching period. Important differences were observed between adult levels of activity. Leg muscle revealed higher enzyme values except for lactate dehydrogenase and indistinguishable levels for adenylate deaminase and xanthine dehydrogenase in both muscles. Alanine, instead of glutamine, is postulated as the main nitrogen transport between muscle and liver in the domestic fowl.     

Ontogenic expression of the two isozymes, Ch1 and Ch2, of chicken muscle acylphosphatase

Activities of the two isozymes, Ch1 and Ch2, of chicken muscle acylphosphatase were measured in breast muscles, leg muscles, and livers of developing chicks from day 11 in ovo to day 15 of free life. Measurement was performed using rabbit antibodies which could selectively precipitate Ch1 or Ch2. The activity contents of both Ch1 and Ch2 in muscles were low before hatching but rapidly increased after hatching. Ch1 showed a more marked increase than Ch2. In liver, on the other hand, the activity contents of Ch1 and Ch2 remained low throughout the period of pre- and post-hatching.     

Tissue glycogen and lactate handling by the developing domestic fowl

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that of plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.     

Amino acid compartmentation in chick blood during the peri-hatching period

Individual amino acid levels and compartmentation in chick blood were measured on day 20 of incubation, at hatching (day 0), or after 1 or 5 days of free life, and compared with those of adult chickens. Blood cell amino acid concentrations were almost one order of magnitude higher than those of plasma, with higher values than those found in mammalian erythrocytes. This difference may be due to the capability for protein synthesis of the nucleated cells coupled with a postulated utilization of amino acids as fuel. The most common pattern of individual plasma amino acid levels was a slight rise at hatching followed by a large decrease, with minimal values for adults. The patterns in the cells did not always coincide with those for plasma. Total blood amino acid levels increased steadily during the period studied due to the increase in intracellular amino acids, giving rise to increasing blood-cell/plasma concentration ratios. These changes showed higher availability of plasma amino acids just after hatching, while the cell concentrations increased steadily to the maximum values in adults. The increase in alanine levels in cells with little changes in plasma can be correlated with the role of this amino acid as the main 2-amino nitrogen carrier in the avian bloodstream. The high amino acid levels in the cells suggest that these cells act as inter-organ transporters and reservoirs of amino acids, they have a different role in their handling and metabolism from those of mammals.     

Tissue glycogen and lactate handling by the developing domestic fowl

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.     

Developmental changes of the content of acetyl-CoA carboxylase mRNA in chicken liver

Utilizing RNA blot hybridization and immunoblotting techniques, the changes of the hepatic contents of acetyl-CoA carboxylase mRNA and of the enzyme protein in growing chicks have been investigated. In the post-hatching period, the hepatic mRNA level markedly increased at least 70-fold when compared to that before hatching. This increase was not observed in chicks receiving no diet. These changes were closely paralleled with the rise of the hepatic content of acetyl-CoA carboxylase protein in chicks up to 10 days old. Neither the acetyl-CoA carboxylase mRNA level nor the enzyme quantity significantly changed in heart. It is concluded from these results that the developmental regulation of acetyl-CoA carboxylase in the post-hatching period of chicks is tissue specific and occurs primarily at a pretranslational step. The content of acetyl-CoA carboxylase mRNA in adult chicken liver was low, which is comparable to those in embryos at 3 days before hatching and chicks at hatching day. Although acetyl-CoA carboxylase mRNA was detected in adult chicken brain, heart, lung, kidney, uropygial gland, spleen, testis, and chest muscle as well as liver, the mRNA level in these tissues was much lower than that in liver of growing chicks.     

Changes in free amino acid concentrations in serum,brain, and CSF throughout embryogenesis

Using the developing chick embryo as a model and a very sensitive micromethod for amino acid analysis, a complete analysis is presented of the developmental changes in free amino acid concentration in the blood, in the CSF, and in two different brain regions (optic lobe and frontal lobe) of the chick embryo (from day 4 of incubation, until day 5 post hatching). The developmental profile of Lys is the only one that is almost identical in all three compartments. The developmental profiles of the serum and of the brain are very similar for Arg and Phe, less so for Leu and Gly, and towards the end of the embryonic period, similar also for Val, Ile, Trp, and Met. The amino acid concentrations in the CSF are either much lower than in serum and brain already at the earliest stages, or they progressively decline to levels lower than those in brain and serum, most rapidly between day 6 and 8 of embryonic life. The concentrations of neuroactive amino acids (Gln, Glu, Asp, GABA, Tau, and Gly) in both brain regions begin to increase very early, and continue to rise, except Tau, which goes through a maximum at day 8. Comparative analysis of the developmental profiles of each amino acid in serum, brain, and CSF reveals that the blood supply and the cellular uptake, retention, and metabolism by neural cells are the major determinants of the free amino acid pool of the developing brain.     

Age-related changes in the incorporation of [14-C] leucine into myofibrillar and sarcoplasmic proteins of red and white muscles of chicks.

Studies on the incorporation of DL-[1- 14-C] leucine into myosin, total myofibrillar protein and total sarcoplasmic protein have shown age-dependent alterations in the rate of synthesis of these protiens in red and white skeletal muscles of chicks. During the early phase of ex ovo development white muscle synthesizes significantly higher amounts of myofibrillar proteins, especially myosin, in comparison with red muscle. The rate of sarcoplasmic protein synthesis in red and white muscles one day after hatching is almost identical. The red muscle shows a markedly higher rate of sarcoplasmic protein synthesis from 10 days after hatching. The incorporation of amino acid into various protein fractions of both the muscle types decreases with advancing age. In adult chicks red muscle displays a higher ability to synthesize sarcoplasmic and myofibrillar proteins.     

Acid soluble, short chain esterified and free carnitine in the liver, heart, muscle and brain of pre and post hatched chicks

1. The behaviour of total acid soluble, short chain esterified and free carnitine in the liver, heart, muscle and brain of chick embryos between 11th and 21st day of development and of 8 and 180-day-old chicks is described. 2. Total acid soluble carnitine fluctuates around the same levels in the brain, liver and muscle until 18th day of development, whereas it attains a peak on that day in the heart. At hatching compared to 18th day, it suddenly increases three times in the muscle, drops not significantly in the heart and brain, but sharply in the liver (-40%). However the levels are always higher than those of the grown chick in the brain but lower in the other tissues. 3. Free carnitine levels are almost constant in all tissues during the embryonic life; if compared to adult ones, they are very much lower in the liver, heart and muscle, but higher in the brain, even in 8 day-old chick. 4. Short chain esterified, carnitine reaches a maximum on 18th day of egg incubation in the liver, brain and heart; in the muscle it stays on constant levels until this day and then rapidly increases so that at hatching it doubles the values. 5. The short chain esterified to free carnitine percentage ratio peaks in all tissues on 18th day of development, attaining figures which are well above those determined in the grown chick.     

Changes in the Levels and Forms of Cholinesterases in the Blood Plasma of Normal and Dystrophic Chickens

Abstract: Acetylcholinesterase (AChE) and pseudocholinesterase (°ChE) were analysed in the blood plasma of developing chickens, both normal and those with inherited muscular dystrophy. The amounts and the molecular forms of each were examined. °ChE concentration rises in the plasma of normal and dystrophic chicks at the end of embryonic development and is maintained after hatching at a constant, relatively high level, accounting for 90-95% of total cholinesterase activity in normal plasma. This level is maintained in normal and dystrophic chickens. In embryonic plasma of both normal and dystrophic chicks, on the other hand, the levels of AChE are higher than those of °ChE. Immediately after hatching the AChE level decreases rapidly in normal plasma, reaching a very low level by 2-3 weeks ex ovo. The AChE level in plasma from dystrophic birds, although less than normal from day 19 in ovo to 2 weeks ex ovo, subsequently increases to peak around 4 months at levels 15-20-fold of those in normal birds. There is virtually no enzyme of either type in the erythrocytes of normal or dystrophic chickens. The changes of AChE in plasma were correlated with the alterations of AChE in dystrophic fast-twitch muscles, suggesting that the latter pool is a precursor of the plasma AChE. Both the AChE and the °ChE in plasma exist in multiple molecular forms, which are similar to certain of those found previously in the muscles of these birds. The major form (60-80%) of both enzymes in the plasma is the M form (sedimentation coefficient ≥11 S) in all cases, but it is accompanied by certain other forms. In no case is there any of the heaviest form (H₂, 19-20 S) of AChE or of °ChE found in normal and dystrophic muscle, which is attached at the synapses in normal muscle. The pattern of forms of plasma °ChE is constant at all ages, and in normal and dystrophic chickens. The pattern of forms of AChE in the plasma, in contrast, varies with age and with dystrophy in a characteristic manner. The sedimentation coefficients and the amounts of the enzymes in fast-twitch muscle of dystrophic animals are compared with those of the plasma forms, and an interpretation is given of the characteristic patterns of AChE and of χE in their blood.     

Changes in plasma, tissue, and urinary nitrogen metabolites due to an inflammatory challenge

Studies were undertaken to define the changes in protein metabolism that result from stimulation of the immune system by noninfectious inflammatory agents. Chicks were injected with inflammatory agents and metabolite concentrations were determined between 4 and 48 hr postchallenge. Inflammatory agents resulted in a generalized decrease in the concentration of plasma nitrogen metabolites, including ammonia, uric acid, urea, and several amino acids. Escherichia coli and sheep red blood cell (SRBC) injections induced changes in the concentrations of tissue-free amino acids at 16 hr postchallenge. After E. coli injections, free amino acid concentrations were increased by 175% in muscle and decreased by approximately 25% in liver, spleen, and bursa. A SRBC challenge resulted in similar decreases in free amino acid concentrations in the spleen and bursa as did E. coli; however, muscle and liver free amino acid concentrations were mostly unchanged. Urinary ammonia was increased, urinary uric acid was decreased, and urinary amino acids were not affected by E. coli injection. These findings indicate that stimulation of the immune system by noninfectious inflammatory agents induces tissue-specific changes in nitrogen metabolism. Changes in amino acid pool sizes in various tissues suggest alterations in rates of protein synthesis or degradation.     

Amino acids in haemolymph, single fibres and whole muscle from the claw of freshwater crayfish acclimated to different osmotic environments

The concentrations of free amino acids were measured in whole claw muscle, single fibres and haemolymph of Australian freshwater crayfish, Cherax destructor, during the intermoult stage. The average total pool of amino acids in short-sarcomere fibres (179 mmol kg(-1)) was 60% greater than in long-sarcomere fibres, due to higher concentrations of alanine, cysteine, glutamate, leucine and proline. The two fibre types exhibited differences in the banding pattern of the isoforms of troponin using gel electrophoresis. The average pool of amino acids in haemolymph was 2.7 mmol kg(-1). Cherax has symmetrical claws and the total pool of amino acids from whole muscles (approx. 79 mmol kg(-1)) was similar in left and right claw muscles. In animals acclimated to osmotic environments between 0 and 220 mOsm, the osmotic pressure of the haemolymph increased from 356 to 496 mOsm, but no systematic changes were observed in the amino acid profiles of muscles or haemolymph. The major findings were that (a) concentrations of amino acids differed between the two major fibre types in claw muscle and (b) amino acids in the muscle fibres did not play a major part in intracellular osmoregulation in Cherax, suggesting this species is an anisosmotic regulator.     

Utilization in vivo of glucose carbon in the optic lobes and the cerebellum of the chick during postnatal growth.

1. The incorporation of glucose carbon in vivo into amino acids was studied in the chick optic lobes and cerebellum during postnatal growth after subcutaneous injection of [U-14C]glucose. 2. The rapid incorporation of glucose carbon into free amino acids appears between the 1st and the 2nd day of postnatal growth in the optic lobes and between the 1st and the 4th day after hatching in the cerebellum. 3. The period during which the properties of mature brain metabolism are obtained is characterized in both structures during the first 48 hr of postnatal growth by changes in the specific radioactivity of some amino acids such as aspartate and alpha-alanine, and also by transient increases of glucose and glutamine concentrations. 4. The gamma-aminobutyrate content in the optic lobes is very high; the cerebellum on the contrary is characterized by its low gamma-aminobutyrate concentration linked to a very fast metabolism of this amino acid.     

Cholesterol alterations in young dystrophic mice

Cholesterol and cholesteryl ester concentrations and cholesteryl ester fatty acid substituents have been measured during the first 10 weeks of life in tissues of normal and dystrophic mice. In normal Swiss and 129ReJ(+/?) mice the concentrations of both cholesterol and cholesteryl esters remain essentially constant in liver, increase in brain and fall sharply in both thigh (mixed fiber type muscles) and chest muscles (predominantly slow oxidative muscles) over this period. In all cases the concentration of free cholesterol exceeds that of esterified cholesterol. In dystrophic mice, similar patterns are found in brain and liver. In both thigh and chest muscles, however, the developmental pattern is significantly different. After an initial decrease the concentrations of cholesterol and cholesteryl esters increase rapidly with the largest increase occurring in the concentration of cholesteryl esters which by 10 weeks of age exceeds the concentration of cholesterol in chest muscle. During the same period the pattern of esterified fatty acids changes gradually in dystrophic tissues towards an increasing ratio of unsaturated/saturated fatty acids. By 10 weeks of age this ratio is significantly higher in dystrophic tissues than normal in all tissues tested.     

Free amino acids in the late embryogenesis and pre-hatching stage of two coregonid fishes

Developing eggs of vendace (Coregonus albula L.) and whitefish (C. lavaretus L.) were experimentally delayed in hatching by incubation at low water temperature (1–2°). Some eggs were taken during this period to a water temperature which was gradually raised up to 8° to provoke mass hatching of embryos. The pattern of free amino acids was followed in eggs incubated at both temperatures. During a 56 days period, the content of several essential amino acids significantly decreased in eggs of both species. For instance, the lysine content dropped from 703 to 270 mg/g dry matter and the arginine content from 257 to 13.3 mg/100 g dry matter in whitefish eggs. A similar pattern of decreasing level of free amino acids in embryonated ova up to hatching was characteristic for essential amino acids and serine. Methionine was exceptional; its level remained approximately the same. On the other hand, non-essential amino acids showed a significant increase in concentration during the experimental period. For instance, the glycine level increased 4.9 and 2.1 times in whitefish and vendace eggs, respectively. Transfer of eggs to 8° accelerated the decrease of nearly all free amino acids before hatching. The consequence of such amino acid metabolism for newly hatched larvae is discussed.     

Amino acid metabolism in the Zucker diabetic fatty rat: effects of insulin resistance and of type 2 diabetes

We investigated amino acid metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic amino acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, alpha-aminoadipic acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain amino acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic amino acids had decreased plasma concentrations. The 3 branched-chain amino acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic amino acids were lower at both stages, whereas the levels of 1 or all of the branched-chain amino acids were elevated. These changes in amino acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in amino acid metabolism observed in type 2 diabetes.     

Development of the mitochondrial apparatus and blood supply of skeletal muscle fibers during ontogenesis of domestic fowl

The diameter, length, and numerical density of capillaries, diameter of muscle fibers, size and numerical density of their profiles, and relative volume of mitochondria in them were determined in the chicken red oxidative gastrocnemius and white glycolytic pectoral muscle during development from day 10 of embryogenesis to six month of postnatal life. The bulk blood flow was measured in these muscles by hydrogen clearance during postembryonic development. During embryogenesis, the fibers of gastrocnemius muscle develop and grow at a higher rate, while during postembryonic development, those of the pectoral muscle develop faster. The density of mitochondrial profiles increases during embryogenesis and decreases after hatching, while their mean size increases, especially in the oxidative fibers, but it somewhat decreases in 6-month old chicks. Redistribution of mitochondria by the fiber section during development takes place in both muscles: they are localized predominantly in the center in 18-day embryos and in the periphery, especially in the gastrocnemius fibers, in 6-month old fowl. At hatching, the lengths of capillaries are similar in both muscles, but as chicks grow, the proportion of longer (more than 600 microm) capillaries in the pectoral muscle sharply increases, while their density and bulk blood flow decrease. Ratios were determined between structural parameters of the capillary bed and mitochondria, on the one hand, and oxygen consumption (ml/min per 1 mm fiber and 100 g muscle mass), on the other.     

Free amino acids in claw muscle and haemolymph from Australian freshwater crayfish at different stages of the moult cycle

Amino acids were measured in claw muscle and haemolymph in the freshwater decapod crustacean, Cherax destructor, at different stages of the moult cycle. The total pool of amino acids in muscles from animals in intermoult (97+/-13 mmol kg(-1) muscle), premoult (80+/-20 mmol kg(-1)) and postmoult (97+/-19 mmol kg(-1)) were not significantly different. Despite the relatively stable total pool of amino acids, there were changes in the concentrations of alanine, glutamine and proline over the moult cycle. Compared to intermoult, claw muscles from animals in premoult had a lower concentration of proline, and animals in postmoult had higher concentrations of alanine and glutamine, but lower concentrations of proline. Concentrations of alanine and glutamine in claw muscle of animals in postmoult were higher and proline concentrations lower than in the same animals during the premoult stage. The concentration of proline in haemolymph was lower in animals in premoult and postmoult compared to intermoult. The total amino acid pool in the claw muscle of Cherax destructor did not change significantly over the moult which is distinctly different to the changes in amino acids reported in the claw muscles of marine decapod crustaceans.     

The effects of starvation on the sodium, potassium, water and free amino acid content of parietal muscle from Agonus cataphractus.

1. The levels of the individual free amino acids, K, Na and water present in parietal muscle were measured in fish starved for periods of 3-115 days. 2. The Na and water content progressively increased relative to dry weight of tissue during the starvation period whereas an initial increase in the K content up to 67 days was followed by a decrease to near the normal fed level by 115 days. The ammonia content remained essentially stable over the same period. 3. The essential free amino acid content tended to follow the muscle sodium pattern while the non-essential amino acids and taurine gave results somewhat similar to those of potassium. 4. The net result of these changes is that the Na, K and total free amino acid concentration is maintained within fairly narrow limits relative to the tissue water content during 11-67 days of the starvation period under the experimental conditions used.