Biomedical subjects

E Decuypere

Publications and source records attributed to E Decuypere.

At least 127 records · Page 7Linked to original sources

PubMed1998

Comparison of the effects of simmondsin and cholecystokinin on metabolism, brown adipose tissue and the pancreas in food-restricted rats.

In this study, we investigated the analogies between the physiological effects of simmondsin, a satiety-inducing glycoside extracted from jojoba seeds, and the gastro-intestinal satiation peptide, cholecystokinin. The effects of intraperitoneal injection of the biological active CCK-octapeptide on the pancreas, interscapular brown adipose tissue, growth performance and energy metabolism in normal-fed, severely food intake-restricted (50 % of normal food intake) or moderately food intake-restricted (65 % of normal food intake) growing rats were compared to the effects of 0.25 % simmondsin mixed in the food, inducing moderate food intake reduction (65 % of normal) in rats. Cholecystokinin induced pancreatic hypertrophy. In normal fed rats, cholecystokinin had no effect on brown adipose tissue or growth, while, in severely food intake-restricted rats, it caused brown adipose tissue hypertrophy and reduced growth. In moderately food intake-restricted rats, both cholecystokinin and simmondsin induced pancreatic hypertrophy, increased brown adipose weight and metabolism and caused a slight decrease in growth. We conclude that cholecystokinin may decrease growth performance in fast growing severely food intake-restricted rats by stimulating brown adipose tissue metabolism, probably because of protein shortage induced by pancreatic hyperstimulation. Simmondsin has similar effects. These results support the hypothesis that endogenous cholecystokinin is involved in the effects of simmondsin in rats.

Acetonitriles↗

PubMed1998

Performance, incidence of metabolic disturbances and endocrine variables of food-restricted male broiler chickens.

1. This experiment was carried out to evaluate the productive and physiological consequences of a slight but long term food restriction of male broiler chickens from 2 commercial strains. 2. Cobb-500 and Ross chickens were submitted to a 20% food restriction from 8 to 21 d of age. Strain, food programme and their interactive effects were analysed in terms of consequences upon performance, mortality, incidence of sudden death syndrome (SDS) and ascites syndrome (AS), index of right cardiac hypertrophy and plasma concentrations of hormones related to metabolism and growth (T3, T4, T3:T4 ratio, IGF-I and GH). 3. Although some catch-up growth was observed by refeeding previously restricted birds after 22 d of rearing, food restriction decreased (P < or = 0.05) body weight at market age (42 d) irrespective of the strain, but improved (P < or = 0.05) food conversion. 4. The incidence of mortality was not high in non-restricted birds but SDS and AS caused more than 50% of deaths. Hypertrophic cardiac index was observed in chickens of both strains after 4 weeks of age and was higher in ad libitum fed birds. 5. During the period of food restriction, plasma T3 and IGF-I concentrations decreased whereas plasma T4 and GH concentrations increased compared to those of the age-matched ad libitum fed counterparts. During the subsequent ad libitum feeding period, few differences in circulating hormone concentrations were observed, except for the higher mean GH litres in previously food-restricted chickens at 35 d of age. 6. These results indicate that even a non-severe food restriction negatively affects body weight of 42-d-old male broilers but these are benefits with improved food efficiency and diminished mortality from metabolic disturbances. The hormone results suggest that the degree of food restriction applied was not severe because there was a very fast adaptive response with small and transient alterations in T3, T4 and GH plasma concentrations during the period of compensatory growth.

Animal Nutritional Physiological Phenomena↗

PubMed1998

Energy and protein metabolism between 3 and 6 weeks of age of male broiler chickens selected for growth rate or for improved food efficiency.

1. A new open-circuit respiration unit consisting of 6 respiration chambers, gas analysis unit and data-acquisition system is briefly described. 2. Energy and protein metabolism in broiler lines selected for improved food efficiency (FC) or for growth rate (GL) were measured weekly from 3 to 6 weeks of age. 3. Gross and apparent metabolisable energy intake per kg W0.75 was on average higher for GL than for FC chickens without differences in metabolisability. Fed and fasted heat production per kg W0.75 did not differ between the lines. FC chickens retained less energy per kg W0.75 than GL chickens. 4. FC chickens deposited much less of the retained energy as fat than their GL counterparts and also showed greater protein conversion efficiency. The leaner composition of the body weight gain in FC chickens was confirmed by the estimated lower fat deposition per kg W0.75 and by the lower fat: protein ratio.

Aging↗

PubMed1998

Intermittent lighting reduces the incidence of ascites in broilers: an interaction with protein content of feed on performance and the endocrine system.

An experiment with 840 day-old male broiler chicks (Ross) was initiated to investigate the effect of intermittent lighting schedules, combined with two isocaloric feeds differing in protein content, on ascites mortality. At 9 d of age, chicks were randomly distributed over two rooms: one room with a 23 h light(L):1 h dark (D) lighting schedule (CL), and another room with an intermittent lighting schedule (IL, 1L:3D). In each room, two isocaloric feeds differing in CP content, supplemented or not supplemented with 1.5 ppm triiodothyronine (T3), were provided. The experiment was repeated under identical conditions except that lighting schedules were changed between rooms. From Day 14 onwards, biweekly growth and feed intake were determined and feed conversion (FCR) was calculated. Daily mortality was recorded and necropsies were performed. Weekly blood samples were taken from 10 randomly chosen birds per experimental group for measurements of growth hormone (GH), thyroid hormones [thyroxine (T4) and triiodothyronine (T3)], and hematocrit values. Birds reared in IL manifested a more concave growth trajectory than those in CL, which was associated with a lower FCR and higher plasma GH levels during the finisher period. Mortality due to ascites was markedly increased by dietary T3 supplementation. In hyperthyroid chickens, ascites mortality was lower in IL than in CL and lower in birds fed normal protein than in those fed subnormal protein levels. Dietary T3 decreased plasma GH and T4 levels, whereas T3 levels were increased. It is concluded that IL or a higher protein content of the feed reduces the incidence of T3-induced ascites mortality. Possible causal mechanisms are discussed.

Animal Feed↗

PubMed1998

Metabolic disturbances in male broilers of different strains. 1. Performance, mortality, and right ventricular hypertrophy.

Two trials were carried out to test the susceptibility for metabolic disturbances of different strains of male broilers. In Trial 1, 1,890 male chickens were allotted in a randomized block design with seven treatments (Arbor Acres, Avian Farms, Cobb-500, Hubbard-Peterson, ISA, Naked Neck, and Ross) and six blocks of 45 chickens. Trial 2 involved 2,184 male chickens of six strains (Arbor Acres, Avian Farms, Cobb 500, Hubbard-Peterson, ISA Naked Neck, and Ross) allotted in seven complete blocks of 52 birds. The same management system was adopted for all birds, reared up to 42 d in an open house during late winter (Trial 1) or late autumn (Trial 2). The most marked differences observed among the strains tested was the lower BW and higher feed conversion of Naked Neck broilers. Total percentage mortalities were high among the most productive broilers, being more than 50% due to sudden death (SDS) and ascites syndrome (AS). No Naked Neck birds died as a consequence of these disturbances and the total mortalities were significantly lower (P < or = 0.05) than the other strains. The ratio of right ventricle weight to total ventricle weight of the dead birds was over 0.25, except for Naked Neck birds, which presented a nonhypertrophic ratio. The two trials confirmed the relationship between high productivity and high incidence of SDS and AS and indicated that Naked Neck male broilers are resistant to these metabolic disturbances.

Animal Feed↗

PubMed1998

The reduction of heat production in exercising pigeons after L-carnitine supplementation.

Four groups (CS,CR,PS,PR) of nine trained male racing pigeons were deprived of feed for 1 d and then subjected to a respiration chamber test in order to study the effect of oral 1-carnitine supplementation on the energy metabolism during flight. One week before, groups CS and CR were orally supplemented with 90 mg of 1-carnitine daily, whereas PS and PR were given a placebo. Groups CS and PS underwent flight simulation by electrostimulation of the breast muscles. Flight simulation increased heat production, kept respiratory quotient from decreasing, decreased thyroxine levels, and increased weight loss. L-Carnitine decreased the rise in heat production during electrostimulation but did not influence respiratory quotient, weight loss, or thyroid hormones. L-Carnitine supplementation in pigeons improves fatty acid combustion efficiency during heavy exercise.

Animals↗

PubMed1998

Quantification of inhibin/activin alpha and betaA subunit messenger ribonucleic acid by competitive reverse transcription-polymerase chain reaction in chicken granulosa cells during follicular development.

The very sensitive quantitative competitive reverse transcription-polymerase chain reaction (RT-PCR) was used to investigate the expression of inhibin/activin subunits in the granulosa cells of developing ovarian follicles of the hen. Two competitors specific to inhibin alpha and betaA subunits were constructed. In one study, the expression of inhibin alpha and betaA genes was determined in the granulosa cells of the five largest yellow follicles (F1, F2, F3, F4/5), the small yellow follicles (SYF), and the large white follicles (LWF) of a layer strain of chickens. Competitive RT-PCR for inhibin alpha subunit revealed 10.35 +/- 2.15 pg/ microg total RNA in the LWF. The expression increased 40-fold in the SYF and remained at that level in the F4/5 but decreased markedly thereafter up to the F1 stage. Inhibin/activin betaA subunit was also detected in the LWF in low amounts and showed no significant increase until the F2 stage. The highest level was found in the F1. The pattern of the mRNA for alpha and betaA subunits in the five largest follicles (F1, F2, F3, F4/5) of a broiler breeder strain of chicken was compared with that in the layer strain. Expression of the alpha subunit was significantly higher in the three largest follicles (F1, F2, F3) of the broiler breeder hens, but only in the F2 for the betaA. The results suggest that inhibin alpha may play an important role in the recruitment and differentiation of follicles and that differences between broiler breeders and layers may have consequences at both the pituitary and ovarian levels.

Activins↗

PubMed1998

Effect of long-term food restriction on pituitary sensitivity to cLHRH-I in broiler breeder females.

The effect of long-term food restriction on the sensitivity of the pituitary to exogenously administered chicken luteinizing hormone releasing hormone I (cLHRH-I) was investigated in three groups of broiler breeder females fed ad libitum, fed a restricted quantity of food or fed a restricted quantity of food to obtain an intermediate body weight between those of the first two groups. At 16 weeks of age, basal FSH release was higher in ad libitum fed birds, culminating in ovarian development and subsequent oestradiol production by the small follicles. At this age, LH secretion was independent of ovarian feedback factors. In all groups, cLHRH-I was most active in releasing LH in intact and ovariectomized animals and, to a lesser extent, in releasing FSH in ovariectomized birds. At 39 weeks of age, basal FSH concentrations were similar among intact animals of all groups, whereas LH concentrations differed among groups, with higher values in the restricted birds. This food effect was enhanced in ovariectomized birds. Furthermore, the high response to cLHRH-I in the ovariectomized, restricted birds compared with the ad libitum, ovariectomized group suggests an improved sensitivity of the hypothalamic-pituitary axis. In conclusion, birds fed ad libitum showed the highest responsiveness to ovarian factors and to cLHRH-I in releasing FSH in the period before sexual maturity. No effect of amount of feeding could be observed for LH. However, during the egg laying period, LH release by cLHRH-I was highly dependent on amount of feeding and on ovarian feedback regulation. This finding indicates that the amount of feeding can modify the sensitivity of the pituitary to cLHRH-I, and possibly to gonadal hormones, during the laying period.

Analysis of Variance↗

PubMed1998

Effect of protein and protein-free energy intake on plasma concentrations of insulin-like growth factor I and thyroid hormones in preruminant calves.

We conducted two experiments with preruminant calves weighing 80 to 240 kg to study the long-term nutritional regulation of circulating IGF-I, thyroxine (T4), and triiodothyronine (T3). The two experiments were similar in design but were performed with calves of two live weight ranges: 80 to 160 kg (Exp. 1) and 160 to 240 kg (Exp. 2). In each experiment, 36 calves were allocated to one of 12 dietary treatments, which consisted of six protein intake levels at each of two energy intake levels. Digestible protein intakes ranged between .90 and 2.72 g N x BW(-.75) x d(-1) in Exp. 1 and between .54 and 2.22 g N x BW(-.75) x d(-1) in Exp. 2. The energy intake levels were kept constant on a protein-free basis; increased energy intakes were realized by increasing energy intake from fat and carbohydrates in a fixed ratio. The digestible protein-free energy intakes were 663 and 851 kJ x BW(-.75) x d(-1) in Exp. 1 and 564 and 752 kJ x BW(-.75) x d(-1) in Exp. 2. Blood samples were taken 5 to 6 h after feeding once every 14 d until the calves reached their target weight. In both experiments, plasma IGF-I and T4 concentrations increased with increasing protein intake (P < .01), but they were unaffected by protein-free energy intake (P > .10). In both experiments, plasma T3 levels were markedly higher at the high protein-free energy intake level (P < .01) and increased slightly with increasing protein intake in Exp. 1 (P = .19) and Exp. 2 (P < .01). Results of these experiments suggest the involvement of IGF-I in the response of protein deposition to increased protein intakes and the involvement of the active thyroid hormone T3 in the response of protein deposition to increased protein-free energy intakes.

Animal Feed↗

PubMed1998

3,3',5-Triiodothyronine (T3) uptake and expression of thyroid hormone receptors during the adaptation to hypothyroidism of the brain of chicken.

Thyroid hormone action in the brain is strictly regulated, since these hormones play a crucial role in the development and physiological functioning of the central nervous system. Hormone kinetics and molecular events at the nuclear receptor level during the adaptation of the brain of chicken to hypothyroidism were simultaneously investigated. Data obtained by Oldendorff's 'single-pass' technique showed a significantly higher labelled 3,3'5-triiodothyronine (125I-T3) uptake into the brain of surgically thyroidectomized (TX) 2-week-old broilers after 1 week of surgery in comparison to sham-operated (SH) and t3 supplemented (TX + T3) controls in the 10th second after the bolus injection. Telencephalons showed the highest, while cerebellum the lowest uptake intensity in all groups. In a similar arrangement of experiments the expression of the TR alpha- and TR beta nuclear thyroid receptors in the telencephalon of TX and control chickens was investigated by a semiquantitative RT-PCR-based approach for beta-actin, then amplified for thyroid receptors. The level of both the TR alpha and TR beta coding mRNA was elevated in hypothyroidism. In conclusion, the presented hormone kinetics and TR expression data provide further details of the cellular and molecular events occurring during the adaptation to hypothyroidism of the brain of chicken.

Animals↗

PubMed1997

Ovarian and extraovarian sources of immunoreactive inhibin in the chicken: effects of dexamethasone.

The present study investigates whether besides the ovary, extragonadal sources contribute to the total amount of immunoreactive inhibin in the plasma of the domestic hen. A comparison of the inhibin content of different organ shows that, expressed per milligram of tissue, the adrenal ranks second only to the ovarian granulosa layer. To explore the contribution of the adrenals to plasma inhibin, dexamethasone (100 micrograms/kg BW) was injected i.v. into intact, ovariectomized, and sham-operated hens. Control animals of each experimental group were injected with saline (0.9% (w/v) NaCI). Dexamethasone significantly (P < 0.05) decreased plasma inhibin concentrations in the three groups. The suppressive effect of dexamethasone in intact hens, however, was caused by a direct effect of this synthetic glucocorticoid on the gonads. Indeed, dexamethasone decreased the production of inhibin by granulosa cells in vitro and also lowered the immunoreactive inhibin concentration in ovariectomized animals. The decreased plasma inhibin concentration in ovariectomized animals is probably due to a direct effect of dexamethasone on the adrenals. Adrenal cells produced immunoreactive inhibin in vitro. The inhibin secretion by adrenal cells was significantly (P < 0.05) depressed by dexamethasone. In conclusion, the ovary is the major source of plasma immunoreactive inhibin in the laying hen. The presence of substantial amounts of immunoreactive inhibin in the adrenal, the secretion of inhibin by cultured adrenal cells, and the decreased immunoreactive inhibin in ovariectomized animals treated with dexamethasone indicate that the adrenal is a likely source of extragonadal inhibin. The nature and the role of this adrenal inhibin remain to be investigated.

Adrenal Glands↗

PubMed1997

The effect of food intake from two weeks of age to sexual maturity on plasma growth hormone, insulin-like growth factor-I, insulin-like growth factor-binding proteins, and thyroid hormones in female broiler breeder chickens.

Plasma concentrations of metabolic hormones were determined in broiler breeders fed on three quantitatively different food regimes in the period prior to sexual maturity. The first group was fed ad libitum, the second group was fed a restricted quantity of food, and the third group was restricted to obtain an intermediate body weight between those of the first two groups. In food-restricted birds, insulin-like growth factor-I (IGF-I) reached the highest plasma concentrations at 8 and 14 weeks of age in contrast with levels in the fully fed animals, in which only one maximum value was observed at 10 weeks. From 14 weeks on, IGF-I concentrations remained higher in the restricted groups compared to the ad libitum group. Three IGF-binding proteins with molecular masses of 28, 34, and 40.5 kDa were detected in the plasma of broiler breeders after Western ligand blotting. The concentrations of the 28- and 34-kDa IGF-binding protein bands showed an age-related pattern in all groups. The intensity of these bands was higher in the restricted groups compared to that of the bands for the fully fed animals. No significant differences between the groups could be observed in the intensity of the 40.5-kDa band. Food restriction resulted in higher plasma concentrations of GH and T4 compared with levels in the fully fed animals. T3 plasma concentrations were higher in the ad libitum fed group than in the restricted groups. In all groups, GH and T3 concentrations decreased with advancing age, whereas T4 increased during the same period. This is the first description of the effects of long-term food restriction prior to the onset of sexual maturity on circulating levels of hormones of the somatotrophic and the thyrotrophic axes in female broiler breeders. The interrelationship between GH, IGF-I, IGFBPs, and thyroid hormone concentrations and differences in subsequent reproductive performance of differently fed broiler breeders requires further investigation.

Aging↗

PubMed1997

Evidence for the presence of immunoreactive inhibin in extragonadal tissues of ovariectomized ewes.

Six ewes were ovariectomized to determine the immediate and long-term effects of removal of ovaries on the immunoreactive concentrations of FSH, LH and inhibin. Three months after ovariectomy, ewes were slaughtered and tissue samples of brain, pituitary, spleen, liver, perirenal fat, lung, kidney, adrenals and uterus were collected to determine the immunoreactive inhibin content. Both gonadotrophins, FSH and LH, increased significantly after ovariectomy. The increase of FSH, however, was more pronounced and remarkably faster than the changes of LH after ovariectomy. Immunoreactive concentrations of inhibin decreased sharply as early as 15 min after ovariectomy and subsequently decreased more gradually until 2 weeks after surgery. From this moment on, the level stabilized at 56% of the initial value. In control ewes, a considerable amount of immunoreactive inhibin is found in tissue samples of ovary, lung, kidney, pituitary and spleen. After ovariectomy, the level of immunoreactive inhibin decreased in spleen and lung samples while an important increase of immunoreactive inhibin is found in adrenals and pituitary. These results demonstrate a differential regulation of LH and FSH after ovariectomy and support an involvement of inhibin only in the immediate changes of FSH after ovariectomy in sheep. They further suggest that the adrenals and the pituitary may be extragonadal sources of inhibin. To explore the eventual contribution of the adrenals to circulating inhibin, dexamethasone (1.4 mg/ewe) and ACTH (200 IU/ewe) were in a following experiment injected intravenously in control and ovariectomized ewes. The lack of any effect of dexamethasone or ACTH on the plasma concentration of immunoreactive inhibin indicate that adrenal inhibin probably does not contribute to circulating inhibin.

Adrenocorticotropic Hormone↗

PubMed1997

Compensatory growth of broiler chickens is associated with an enhanced pulsatile growth hormone (GH) secretion: preferential amplification of GH secretory burst mass.

1. The present study was conducted to establish the effect of compensatory growth of broiler chickens on pulsatile growth hormone (GH) secretion. 2. Exposing male broiler chickens to intermittent lighting (IL) at 10 d of age was associated with a transient reduction in body weight gain which was followed by compensatory growth from 4 weeks of age onwards. At 34 d of age, cannulated IL broiler chickens manifesting compensatory growth and control chickens reared under continuous illumination (CL) were serially sampled at 10 min intervals over 5 consecutive hours and plasma GH concentrations measured. The resultant GH time series were analysed by deconvolution analysis. 3. The overall mean GH concentration was higher for IL than for CL broilers. The burst frequency did not differ between lighting treatments, but during each GH surge, IL broilers released a higher GH mass which resulted in higher GH amplitude values. As a consequence, GH production rates of IL broilers during the entire sampling session were markedly elevated compared to those of their age-matched CL broilers. There were no differences in the monoexponential GH half-life. 4. Compensatory growth in broiler chickens is associated with an amplification of GH secretory burst mass. The underlying causal mechanisms remain to be elucidated.

Activity Cycles↗

PubMed1997

Physiological inhibition of growth hormone secretion by both insulin-like growth factors-I and -II in chickens.

1. The role of both insulin-like growth factors (IGF)-I and -II in regulation of growth hormone (GH) secretion in chickens was examined. Seven-week-old male broiler chickens were injected intravenously (i.v.) with recombinant human IGF-I or IGF-II or specific anti-IGF-I or IGF-II immunoglobulins. Blood samples were taken before treatment and at 15 min intervals afterwards for 1 h. Controls received saline i.v. 2. Both IGF-I and IGF-II administration resulted in a rapid, significant decrease in plasma GH concentrations, but the concentrations of both triiodothyronine and thyroxine remained unchanged. 3. Immunisation against both IGF-I and IGF-II produced a significant elevation in plasma GH. 4. These data show that both IGFs can regulate GH concentrations in birds. Furthermore, the immunoneutralisation data suggest that these hormones have a physiological role in the regulation of GH secretion.

Animals↗

PubMed1997

Production of egg proteins, enriched with L-leucine-13C1, for the study of protein assimilation in humans using the breath test technique.

Protein assimilation and metabolism studies are hindered by the lack of an adequate oral tracer, i.e., labeled proteins. We present a new and easily reproducible methodology for producing large amounts of egg proteins labeled with L-leucine-13C1. Laying hens were fed a 0.2% leucine-deficient food supplemented with 0.2% L-leucine-13C1 (99 atom %). At plateau, eggs containing highly enriched proteins were obtained. The 13C content of egg white relative to the total C content was 1.3371 atom %, corresponding to delta = 206%. The overall tracer recovery in egg proteins was high (40.2%), making this method financially attractive as well. Accurately measurable levels of 13CO2 in breath were obtained after ingestion of a physiological load of labeled egg white proteins. Thus, egg proteins with sufficient 13C enrichment and applicable for human protein assimilation and metabolism kinetic studies were produced in an easily reproducible and highly efficient manner.

Adolescent↗

PubMed1996

Evidence for suppression of immune function by insulin-like growth factor-1 in dwarf rats in vivo.

These studies were undertaken to investigate the effects of increasing or decreasing IGF-1 levels on aspects of immune function in rats. Female dwarf rats were treated with recombinant human IGF-1 or with a potent sheep anti-IGF-serum. Body weight, thymus weight and spleen weight increased with IGF-1 treatment (p < 0.001), while there was no effect of anti-IGF-1 treatment when compared with the appropriate normal sheep serum (NSS) treated controls. IGF-1 treatment significantly decreased WBC and RBC counts, but increased the ratio of CD4+:CD8+ T-cells. Anti-IGF-1 serum had no effect on these parameters compared with NSS. However anti-IGF-1 was associated with increased T-cell numbers, decreased natural killer cells, and enhancement of the animals' ability to produce specific IgG in response to injection of keyhole limpet haemocyanin (KLH). These results indicate that IGF-1 may suppress immune function although increasing the size of immune organs such as spleen.

Animals↗

PubMed1996

Plasma thyroid hormone and growth hormone patterns in precocial Japanese quail and altricial European starlings during postnatal development.

Plasma concentrations of thyroid hormones (TH) and growth hormone (GH) during postnatal development in the precocial Japanese quail (Coturnix japonica), and the altricial European starling (Sturnus vulgaris) were measured. Developmental changes in plasma TH found in the starling, differ considerably from those detected in quail. In quail rather high triiodothyronine (T3) values were measured during the first few days after hatching. Subsequently a steady decrease of plasma T3, to adult levels, was observed. Thyroxine (T4) concentrations did not change significantly during the period studied. In starlings, on day 1, plasma T3 was low and T4 was at or below the assay detection limit. An increase in concentrations of both hormones occurred between day 1 and day 5 after hatching. A gradual increase of T4 occurred afterwards, while plasma T3 levels remained nearly constant during this growing period. Plasma GH concentrations showed a similar pattern in both species. There was an increase during first days after hatching and GH concentrations peaked at day 7 in quail and day 5 in starlings. A subsequent decrease was observed in both species. Although the GH profiles in species studied were comparable, there were noticeable differences in their growth rates. Thus different developmental strategies have been reflected in different developmental patterns of TH in precocial Japanese quail and altricial European starling whereas developmental changes of GH levels were similar in both species.

Aging↗