PubMed Health⌕ Search

Biomedical subjects

M M Mashaly

Publications and source records attributed to M M Mashaly.

53 records · Page 3Linked to original sources
PubMed1985

Maturation of the diurnal rhythm of corticosterone in female domestic fowl.

The purpose of this study was to examine the maturation of the avian corticosterone diurnal rhythm in relation to other indices of adrenocortical maturation. Female chickens were studied at 1, 5, 11, 17, 23, and 55 weeks of age. Blood samples were drawn at 4-hr intervals during a 24-hr (14 hr light: 10 hr dark) photoperiod. The diurnal rhythm in corticosterone concentration was not apparent until 11 weeks of age. At this age, unlike at 17 weeks of age, the maximal corticosterone concentration occurred during the light period. This indicates that although a rhythm is present at 11 weeks, a phase shift apparently occurs before the adult-like diurnal rhythm is attained. Injection of adrenocorticotropin (ACTH) produced an increase in the circulating corticosterone concentration in chickens at all ages. These results indicate 1) a phase shift must occur between the time of the initial emergence of a diurnal corticosterone rhythm and the attainment of the characteristic adult-like diurnal rhythm, and 2) the avian adrenal cortex is capable of responding to an ACTH stimulus with an increase in circulating corticosterone before the central nervous system rhythmically controls the pattern of circulating ACTH or corticosterone.

Adrenal Cortex↗
PubMed1984

Effect of adaptation to handling on the circulating corticosterone concentration of laying hens.

Single Comb White Leghorn hens were used to determine the effects of adaptation to handling on circulating corticosterone concentrations. Blood samples were collected either by brachial venipuncture (BVP) or by brachial vein cannula (BVC). Half of the birds in each group were first adapted for 1 week to the handling procedure. Adaptation to handling resulted in reduced plasma corticosterone concentrations.

Adaptation, Physiological↗
PubMed1984

Serum testosterone concentration during two hours of moderate intensity treadmill running in trained men and women.

The purpose of this study was to determine alterations in testosterone concentration in women during 2 hours of moderate intensity running, and to compare this response to that seen in men. Maximal oxygen uptake (VO2 max) and anaerobic threshold (AT) were determined in 11 men and 9 women. These subjects subsequently ran for 2 hours on a motor-driven treadmill at 10% below the AT which was approximately 70% VO2 max. Blood samples were drawn at 0, 30, 60, 90 and 120 minutes of exercise and testosterone was measured by specific radioimmunoassay. Serum testosterone concentration was significantly increased (41%, P less than .01) after 30 minutes of exercise in the men. In the women, testosterone was not significantly increased from pre-exercise concentrations until 120 minutes of exercise (48%, P less than .01). At this time the testosterone concentration in the men had decreased and was no longer significantly elevated from the pre-exercise concentration. The magnitude of the increases in serum testosterone concentration can probably be accounted for by decreases in the metabolic clearance rate of sex-steroids known to occur during exercise. Differences in the testosterone response between men and women during prolonged aerobic exercise are of interest and may imply that different mechanisms of control are involved.

Adolescent↗
PubMed1984

Effect of increased bird population in a fixed cage area on production and economic responses of single comb white leghorn laying hens.

Quantitative relationships between the cage area allotted per hen and parameters associated with egg production were examined by regression analysis. Hens were placed 3, 4, and 5 birds per cage (30.5 x 50.8 cm) with 516, 387, and 310 cm2 of floor area per hen, respectively. Egg production declined as the area per hen was reduced. There was no numerical difference for feed consumption per dozen eggs between 516 or 387 cm2 per hen. Feed conversion was less efficient when the area was reduced to 310 cm2 per hen. Feed conversion when adjusted to 20 dozen eggs accentuated the decline in efficiency as previously noted. Mortality was significantly related to a reduction in cage area per hen. Egg weight tended to increase as the allotted area per bird decreased. Eggs produced and feed consumed per cage were highly correlated to bird numbers per cage area. An economic analysis based on dozens of eggs produced, feed consumption, egg and feed prices, grower payment, and pullet cost showed that profitability associated with increased bird numbers in a fixed cage area is sensitive to changes in egg and feed prices.

Animal Feed↗
PubMed1984

Effect of caponization on cell-mediated immunity of immature cockerels.

The effect of gonadectomy was determined on cell-mediated immune response of immature male chickens. Single Comb White Leghorn males were castrated at 3 weeks of age. Response to phytohemagglutinin (PHA) injection as well as graft vs. host (GvH) response were measured at 5, 10, and 15 weeks of age to evaluate cell-mediated immunity. The PHA and GvH responses were inhibited in castrated males. The results suggest that physiological levels of testosterone are needed to stimulate cell-mediated immune response in immature male chickens.

Animals↗
PubMed1984

Bursectomy and its influence on circulating corticosterone, triiodothyronine, and thyroxine in immature male chickens.

This investigation was carried out to determine the effect of bursectomy on circulating corticosterone, triiodothyronine (T3), and thyroxine (T4) in immature male chickens. One-day-old Single Comb White Leghorn male chicks were surgically bursectomized ( BSX ). Shamoperated chicks were used as control. Blood samples were collected from different BSX and sham birds at 2, 3, and 4 weeks of age. Serum concentrations of corticosterone, T3 and T4 were measured using radioimmunoassays. Serum concentrations of corticosterone and T3 were higher in BSX than sham-operated birds at all ages. Concentrations of T4, however, were similar in both groups. It was concluded that the bursa, directly or indirectly, affected hormone secretion from the thyroid and adrenal glands.

Age Factors↗
PubMed1984

Changes in serum corticosterone concentration of laying hens as a response to increased population density.

The response of adrenal glands of Single Comb White Leghorn laying hens housed under different population densities was studied. The birds were reared in floor pens until they were 19 weeks of age, after which they were housed in cages. Cage size was 30.5 X 50.8 cm. Three, four, or five birds were housed per cage. Corticosterone concentrations were measured in all birds 48 and 96 hr following housing in cages and weekly thereafter for 6 weeks. Corticosterone concentrations were consistently higher in the serum of birds housed five per cage than in birds housed three or four per cage. It was concluded that in order to minimize physiological stress in cage layers, more than 387 cm2 per bird should be considered.

Adrenal Glands↗
PubMed1983

Hypothyroidism and antibody production in immature male chickens.

This study was conducted to determine if hypothyroidism has an effect on humoral immunity in immature male chickens. Two week old Single Comb White Leghorn male chicks were used as experimental animals. Two experiments were conducted using different methods to induce hypothyroidism. In Experiment 1, birds were surgically thyroidectomized (Tx group) and in Experiment 2, hypothyroidism was induced by supplementing the feed throughout the experiment with 0.1% propylthiouracil (PTU group). Antibody production against sheep red blood cells (SRBC) (thymus-dependent antigen) and Brucella abortus (BA) (thymus-independent antigen) was tested at 4 weeks of age. Serum concentrations of T4 and T3 were measured in birds from each treatment group at 5 and 9 weeks of age. Body weights were recorded and birds were then autopsied and thyroid gland weights were measured. Hypothyroidism was successfully induced in both Tx and PTU birds, as reflected by significant reduction in body weights in both groups, enlargement of thyroid glands in PTU birds and absence of thyroid glands in Tx birds. Though T4 and T3 were reduced in sera of treated birds, considerable amounts of these hormones were detected. Hypothyroidism did not seem to have profound or consistent effects on antibody production against SRBC or BA. The possibility that thyroid hormones play a role in antibody production was not ruled out. However, it was suggested that within the physiological range of thyroid gland activity, thyroid hormones may not significantly regulate antibody production.

Animals↗
PubMed1983

Effect of photoperiod on body weight and reproductive performance of ringneck pheasants.

This study was conducted to determine the effects of exposing ringneck pheasants to different photoperiods on their body weights and reproductive performance. Ringneck pheasants were obtained from commercial sources for the first experiment and from the Pennsylvania Game Commission for the second. Birds were exposed to different periods of nonstimulatory light (8 hr of constant light and 16 hr of darkness daily) before they received 16 hr of light and 8 hr of darkness daily (stimulatory light). Data on body weight, feed consumption, semen volume, fertility, and egg production were obtained. The results indicated that ringneck pheasants grow faster when exposed to a period of nonstimulatory light. It was concluded that, if pheasant hens are to be raised under confinement and receive stimulatory light at 27 weeks of age, they should be exposed prior to that time to at least 6 weeks of nonstimulatory light.

Age Factors↗
PubMed1982

Relationship between progesterone and egg production in pheasants.

A radioimmunoassay was developed to measure progesterone concentration in sera of immature and mature female pheasants. The antiserum to progesterone was produced against progesterone-3-carboxymethyloxime: bovine serum albumin in female rabbits. Crossreactivity of the antiserum with 17 different steroids was tested and was less than 2% for all steroids except 5 alpha-pregnane-3,20-dione (18%) and pregnenolone (9%). Sensitivity of the standard curve was 2.7 pg. The within and between assay coefficients of variation were 7% and 14%, respectively. Blood samples were collected weekly starting when the birds were 17 weeks of age and continued until they were 1 year of age. Progesterone concentration was measured in all serum samples. Egg production was recorded daily for the individual hens. The relationship between progesterone concentration and egg production was studied. Average progesterone concentration prior to sexual maturity was significantly lower than at subsequent ages. There was a significant positive correlation between average progesterone concentration and average percent egg production within individual birds. Furthermore, statistically a significant amount of the variation in percent egg production was explained by differences in progesterone concentration. These results indicate that progesterone is important for egg production in pheasants, as it is in chicken and turkey hens.

Animals↗
PubMed1979

Thrombocyte migration and the release of thrombocyte inhibitory factor (ThrIF) by T and B cells in the chicken.

The elaboration of various inhibitory factors by sensitized lymphocytes has been reported for both mammals and birds. Until recently, the ability of the B cell to elaborate these had been questioned by a number of investigators. We have demonstrated the release of a lymphocyte inhibitory factor from the avian thymus and bursal lymphocyte. The avian thrombocyte is active in haemostasis as well as being a phagocytic cell. We have demonstrated that the ability of the thrombocyte to migrate, significantly exceeded that of thymic lymphocytes. Sensitized T and B cells, as well as activated supernatants from these cells, were capable of inhibiting thrombocyte migration. Treatment of sensitized B cells with anti-T-cell serum plus complement failed to eliminate this cell's ability to block thrombocyte migration. These data attribute the capability of elaborating a thrombocyte migration inhibitory factor to both the avian thymic and bursal lymphocyte, and attribute a degree of maturity to these cells not previously demonstrated.

Animals↗
PubMed1976

Plasma LH progesterone concentrations in the turkey hen during the ovulatory cycle.

Progesterone and luteinizing hormone (LH) were measuured in the plasma of Large White turkey hens at frequent intervals during the ovulatory cycle and during the periods when ovulations did not occur. The hormones were quantitated at the beginning and the end of the reproductive season to follow the change in patterns and concentrations of these hormones. Radioimmunoassay procedures were used to assay both hormones. Both progesterone and LH reached a peak amount at about 8 to 2 hours before ovulation. At no time did the progesterone peak precede that of LH. On the other hand, the peak of progesterone was observed to last somewhat longer than the LH peak. Progesterone and LH concentrations demonstrated no peak during the non-ovulatory periods. The patterns of both hormones at the end of the reproductive season was about the same as at the beginning of the season, but with lower concentrations.

Animals↗