The relationship between plasma testosterone concentrations and the seasonal variation in voluntary feed intake in fallow bucks (Dama dama)

1998 ◽  
Vol 130 (3) ◽  
pp. 357-366 ◽  
Author(s):  
R. E. NEWMAN ◽  
S. J. McCONNELL ◽  
R. H. WESTON ◽  
M. REEVES ◽  
C. BERNASCONI ◽  
...  
Keyword(s):  
Feed Intake ◽  
Plasma Concentrations ◽  
Plasma Free Fatty Acid ◽  
Reproductive Behaviour ◽  
Fallow Deer ◽  
Plasma Testosterone ◽  
Control Group ◽  
Voluntary Feed Intake ◽  
Natural Photoperiod ◽  
The Relationship

In two experiments conducted at Badgery's Creek, NSW (Latitude 34°S) the roles of testosterone and the thyroid hormones triiodothyronine (T3) and thyroxine (T4) as possible initiators of the change in voluntary feed intake (VFI) associated with the seasonal reproductive behaviour (rut) in male fallow deer were investigated.In Expt 1, the association between changes in these hormones with the onset of the rut was assessed in deer in which the timing of this event was manipulated by changing the photoperiod, or by melatonin administration. Groups were maintained under either natural photoperiod (n=6; control), a constant long daylength (16 h light[ratio ]8 h dark; n=9; LD group) or a constant long daylength and implanted with melatonin capsules (n=5; LD+M group) for 7 months from December until the following July. Blood samples were obtained weekly and VFI recorded.Feed intake decreased by 94% from the last week of March for 3 weeks in the control group. Changes of a similar magnitude were measured in the LD and LD+M groups but these changes were advanced by 1 and 9 weeks respectively in these groups. In all groups, circulating testosterone concentrations increased markedly at a time corresponding with the decrease in VFI. The concentrations returned to basal levels with the resumption in VFI. A distinct decrease in plasma concentrations of T3 and T4 in all three groups was associated with the decrease in VFI, however, the relationship with T3 was less apparent.In Expt 2, the role of testosterone in the regulation of the decline in VFI was investigated. Fallow bucks were treated with testosterone enanthate every 4 or 5 days for 28 days up to 6 weeks prior to the expected onset of the rut. Plasma testosterone concentrations, which were increased 13-fold, resulted in a decline in VFI which was comparable to that observed in the subsequent rut. Plasma free fatty acid concentrations were correlated negatively with the decline in VFI.Thus, the seasonal increase in circulating testosterone concentrations plays an important role in initiating the fall in VFI associated with the rut. As the rut was still apparent in animals maintained under an extended photoperiod, it is possible that factors other than decreasing daylength act as the cue for the timing of the rut.

Influence of Customized Supplement on Voluntary Feed Intake and Nutrient Metabolism in Crossbred Calves

2020 ◽  
Author(s):  
Sandeep K Chaudhary ◽  
Narayan Dutta ◽  
S E Jadhav ◽  
A K Pattanaik
Keyword(s):  
Wheat Straw ◽  
Feed Intake ◽  
Control Group ◽  
Standard Diet ◽  
Nutrient Metabolism ◽  
N Retention ◽  
Cereal Straw ◽  
Voluntary Feed Intake ◽  
Concentrate Mixture ◽  
P Retention

The present study was carried out to ascertain the effect of dietary inclusion of a customised supplement to farmers’ based diet on voluntary feed intake and nutrient metabolism in crossbred calves. In order to carry out the experiment, fifteen crossbred calves (18 months old; 166.53±4.93 kg mean BW) were randomly allocated to 3 groups (5 calves in each group) as CON, Treat and SBR, in a CRD for 30 days. The calves in CON (control) group were fed on cereal straw based diet with concentrate mixture as per the farmers’ practices, whereas, the calves in Treat were fed according to CON with additional customized supplement @ 0.25% of BW. The calves in SBR group were fed standard diet as per Kearl (1982). The intake (gd-1) of DM and OM was significantly Pandlt;0.01 higher in SBR than Treat and CON groups, while DM and OM intake as % of BW in Treat group has an intermediate position between SBR and CON groups. The concentrate intake (gd-1) was significantly Pandlt;0.001 higher in SBR followed by Treat and CON group, respectively. However, intake of wheat straw and green maize was found to be identical Pandlt;0.05 among all the groups. The digestibility coefficient of DM, OM, CP, NDF and ADF was significantly Pandlt;0.05)higher in Treat and SBR groups than CON. The N-retention as per cent of intake and absorbed-N was significantly Pandlt;0.001 higher in Treat and SBR groups than CON. The Ca and P retention gd-1 was significantly Pandlt;0.001 higher in SBR group followed by Treat and CON groups. The intake gd-1 and density % of DCP and TDN were significantly Pandlt;0.001 higher in SBR group followed by Treat and CON groups. Thus, it can be concluded that supplementation of the customised supplement (@ 0.25% of BW) to CON diet significantly improved the voluntary feed intake and nutrient metabolism in crossbred calves.

Corrigendum - Seasonal variation in voluntary feed intake and growth in cashmere bucks fed ad libitum diets of low or high quality

1994 ◽  
Vol 45 (2) ◽  
pp. 355
Author(s):  
SW Walkden-Brown ◽  
BW Norton ◽  
BJ Restall
Keyword(s):  
Diet Quality ◽  
Feed Intake ◽  
Growth Rates ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Growth Cycle ◽  
High Quality ◽  
Voluntary Feed Intake ◽  
Natural Photoperiod ◽  
Ad Libitum

The effects of season and diet quality on voluntary feed intake and growth were examined in mature cashmere bucks over a 16 month period at Wollongbar (29�S., 153� E.). Three-year-old bucks were individually housed under natural photoperiod and fed ad libitum diets of High (pelleted lucerne, CP 17.6%, ME 8.3 MJ/kg) or Low (pasture hay; CP 6.9%, ME 6.6 mJ/kg) quality, between July 1988 and Oct. 1989 (n = 6/treatment). Bucks on both diets exhibited a seasonal pattern in voluntary feed intake with maximal intakes during spring and summer, and minimal intakes during autumn. The pattern appeared to be circannual with high intakes during spring of both years. Liveweight also varied with season peaking in mid to late summer and reaching a seasonal nadir in late autumn or early winter. Change in liveweight was closely associated with digestible energy intake ( r = 0-87, P < 0.001) resulting in a growth cycle closely resembling that of voluntary feed intake. In both treatments, bucks lost weight throughout autumn, while growth rates were maximal between mid-winter and mid-spring. Diet quality did not alter the magnitude of the autumnal decline in liveweight with bucks losing 7.6% (Low) and 7.8% (High) of liveweight during this period. However, bucks on the high quality diet exhibited significantly elevated growth rates between mid-winter and mid-spring. We conclude that mature cashmere bucks exhibit an annual growth cycle with weight loss during autumn and maximal weight gains between mid-winter and mid-spring; that the growth cycle is driven primarily by changes in voluntary feed intake; and that increasing diet quality does not reduce the autumnal decline in liveweight but significantly increases liveweight gain during the seasonal peak in growth.

scholarly journals Lack of response to garlic fed at different dose rates for the control of Haemonchus contortus in Merino wether lambs

2009 ◽  
Vol 49 (12) ◽  
pp. 1093 ◽  
Author(s):  
V. J. Strickland ◽  
J. S. Fisher ◽  
W. T. Potts ◽  
G. W. Hepworth
Keyword(s):  
Feed Intake ◽  
Haemonchus Contortus ◽  
Body Condition Score ◽  
Control Group ◽  
Feed Conversion ◽  
Worm Count ◽  
Treatment Groups ◽  
Dose Rates ◽  
Voluntary Feed Intake ◽  
Over Time

With the increased incidence of parasite resistance to chemical anthelmintics worldwide novel approaches to manage parasite infection, such as medicinal plants and their extracts, are being investigated by the scientific community. The current study tested the effect of three rates of garlic (0.9, 1.8 and 3.6%) in a pelleted ration on Haemonchus contortus in sheep. Thirty-nine Merino wether lambs aged 6 months were divided into five treatment groups, including three garlic dose rates and two control groups that received no garlic. All animals were infected with 4000 L3 H. contortus larvae 3 weeks after allocation to treatments. A positive control group was drenched with abamectin 28 days after infection. The synthetic drench was effective in controlling the parasites, but there was no reduction in either worm egg counts (WEC) or total worm count due to the garlic. The 3.6% garlic treatment had significantly lower (P < 0.05) liveweight, feed intake, body condition score and feed conversion ratio than any of the other treatment groups, suggesting that this level of garlic had a low level of anti-nutritional properties. There was an interaction between faecal WEC and voluntary feed intake over time, with the animals with higher voluntary feed intake having lower WEC over time.

Plasma Concentrations of C-Reactive Protein and Fibrinogen in Ischaemic Stroke

2002 ◽  
Vol 30 (6) ◽  
pp. 591-596 ◽  
Author(s):  
İ İyigün ◽  
Y Bakirci
Keyword(s):  
Ischaemic Stroke ◽  
Cerebral Artery ◽  
Plasma Concentrations ◽  
Control Group ◽  
C Reactive Protein ◽  
Arterial Lesion ◽  
Reactive Protein ◽  
The Difference ◽  
Unconscious Patients ◽  
The Relationship

This study investigated how fibrinogen and C-reactive protein (CRP) levels change in response to neural damage occurring after ischaemia, and the relationship between the distribution of the arterial lesion, the disease prognosis and the levels of these substances. Fibrinogen and CRP levels were measured in blood samples obtained from 83 patients admitted to hospital within 72 h of a first ischaemic stroke. The patients were evaluated clinically with the Glasgow Outcome Scale (GOS), and results were compared with 43 age-matched controls. The fibrinogen and CRP levels in unconscious patients with hemiparesis or hemiplegia were higher than those in conscious hemiplegic patients. Also, the difference in GOS values between the unconscious patients with hemiparesis or hemiplegia and conscious patients with hemiparesis or hemiplegia was statistically significant. Patients with large infarcts in the median cerebral artery and anterior cerebral artery had higher fibrinogen and CRP concentrations than the control group. In conclusion, fibrinogen and CRP may be important measures for determining the prognosis and outcome in patients following ischaemic stroke.

Comparison of seasonal patterns of growth, voluntary feed intake and plasma hormone concentrations in young sambar deer (Cervus unicolor) and red deer (Cervus elaphus)

1995 ◽  
Vol 125 (1) ◽  
pp. 109-124 ◽  
Author(s):  
G. Semiadil ◽  
T. N. Barry ◽  
P. D. Muir
Keyword(s):  
Feed Intake ◽  
Red Deer ◽  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Seasonal Patterns ◽  
Scrotal Circumference ◽  
Voluntary Feed Intake ◽  
Early Autumn ◽  
Sambar Deer ◽  
Plasma Prl

SUMMARYDuring 1991/93, young sambar (5 months old) and red deer (7 months old) were confined indoors in individual pens in New Zealand and fed a pelleted concentrate diet (12 MJ ME/kgDM; 2·9% N) ad libitum for 21 months. Seasonal patterns of voluntary feed intake (VF1), liveweight gain (LWG), scrotal circumference and plasma concentrations of prolactin (PRL), luteinizing hormone (LH), testosterone (T) and progesterone (P) were compared using five stags and three hinds of each species.Red deer showed a strong pattern of seasonality, with high VFI and LWG in summer and low VF1 and LWG in winter and with peak plasma T and scrotal circumference in stags in early autumn. Compared with red deer, sambar showed weaker seasonal patterns of VFI and LWG, with maximum values in autumn and minimumvalues in spring. Over a complete 12-month cycle, sambar deer gained similar amounts of liveweight to red deer but consumed substantially less feed, thus demonstrating a more efficient conversion of feed tobodyweight. Metabolizable energy (ME) requirements for both maintenance and gain were substantially lower for sambar than for red deer. Scrotal circumference and plasma T values in sambar stags attained their highest values during late autumn, winter and spring, but with a lower magnitude than peak values for red stags. Plasma PRL concentrations were seasonal in both species, with highest values in summer and lowest values in winter. Rapid increase of plasma P was first detected in red hinds in autumn and sambar hinds in spring when they weighed 96 and 90 kg respectively, and were aged 17 and 14 months. Rapid increase of plasma T was first detected in red stags in early autumn and sambar stags in mid-autumn whenthey weighed 117 and 101 kg, and were aged 16 and 15 months respectively.It was concluded that sambar deer had endogenous cycles of VFI, body growth and hormone secretion, which were of lesser amplitude and with different seasonality from those of red deer. Young sambar deer were more efficient feed converters than red deer, and attained sexual maturity at an earlier age and lower liveweight.

scholarly journals Behavioral and Steroidogenic Pharmacology of Phenyl Ring Substituted Etomidate Analogs in Rats

2019 ◽  
Author(s):  
Megan McGrath ◽  
Aissa Hofmann ◽  
Douglas Eric Raines
Keyword(s):  
Gabaa Receptor ◽  
Cushing’S Syndrome ◽  
Phenyl Ring ◽  
Plasma Concentrations ◽  
Plasma Corticosterone ◽  
Cushing's Syndrome ◽  
Plasma Testosterone ◽  
Control Group ◽  
General Anesthetic ◽  
Androgenic Steroids

Abstract Background: Cushing’s syndrome is an endocrine disorder characterized by the overproduction of adrenocortical steroids and associated with significant morbidity. Steroidogenesis enzyme inhibitors are the mainstays of pharmacological treatment. Unfortunately, they produce side effects that limit dosing, efficacy, and patient tolerability. Among the most potent inhibitors is the general anesthetic etomidate whose GABAA receptor-mediated sedative-hypnotic actions restrict use. In this study, we defined the sedative-hypnotic and steroidogenesis inhibiting actions of etomidate and four phenyl-ring substituted etomidate analogs (dimethoxy-etomidate, isopropoxy-etomidate, naphthalene-etomidate, and naphthalene(2)-etomidate) that possess negligible GABAA receptor modulatory activities. Methods: In the first set of experiments, male Sprague-Dawley rats were assessed for loss of righting reflexes (LoRR) after receiving intravenous boluses of either etomidate (1 mg/kg) or an etomidate analog (40 mg/kg). In the second set of experiments, rats were assessed for LoRR and their abilities to produce adrenocortical and androgenic steroids after receiving 2-hr infusions (0.5 mg kg-1min-1) of either etomidate or an etomidate analog. Results: All rats that received etomidate boluses or infusions had LoRR that persisted for minutes or hours, respectively. In contrast, no rat that received an etomidate analog had LoRR. Compared to rats in the vehicle control group, rats that received etomidate analog infusions had plasma corticosterone and aldosterone concentrations that were reduced by 80 – 84% and 68 – 94%, respectively. Rats that received etomidate infusions had plasma corticosterone and aldosterone concentrations that were also significantly reduced (by 92% and 96%, respectively). Rats that received etomidate or isopropoxy-etomidate had significant reductions (90% and 57%, respectively) in plasma testosterone concentrations whereas those that received naphthalene-etomidate had significant increases (1,400%) in plasma dehydroepiandrosterone concentrations. Neither etomidate nor any etomidate analog significantly affected plasma androstenedione and dihydrotestosterone concentrations. Conclusions: Our studies demonstrate that the four phenyl-ring substituted etomidate analogs form a novel class of compounds that are devoid of sedative-hypnotic activities and suppress plasma concentrations of adrenocortical steroids but vary in their effects on plasma concentrations of androgenic steroids. They provide a proof-of-concept for the development of non-sedating etomidate analogs to treat Cushing’s syndrome and other pathologies whose clinical courses may be improved by altering steroid biosynthesis.

Blockade of the neonatal rise in testosterone by a gonadotrophin-releasing hormone antagonist: effects on timing of puberty and sexual behaviour in the male marmoset monkey

1994 ◽  
Vol 141 (3) ◽  
pp. 439-447 ◽  
Author(s):  
S F Lunn ◽  
R Recio ◽  
K Morris ◽  
H M Fraser
Keyword(s):  
Plasma Concentrations ◽  
Reproductive Behaviour ◽  
Treated Group ◽  
Plasma Testosterone ◽  
Long Term Effects ◽  
Gnrh Analogues ◽  
Releasing Hormone ◽  
Marmoset Monkey ◽  
Sexual Behaviours ◽  
Body Weight Data

Abstract In primates, plasma testosterone concentrations are elevated for some 3 months from birth. The function of this rise is uncertain, but studies in rats suggest that its prevention by castration or administration of gonadotrophin hormone-releasing hormone (GnRH) analogues has effects on development and expression of social and sexual behaviours, and adverse long-term effects on fertility. The consequences of suppression of this rise in testosterone by treatment with the GnRH antagonist antide have been investigated in the marmoset monkey. Eight sets of male:male twins were used, one of each set receiving s.c. injections of antide (10 mg/kg), on days 0, 3 and 7, then weekly from birth to 98 days of age, with the twin receiving vehicle only. Plasma samples were taken at weekly intervals for the determination of testosterone concentrations from birth until 2 years of age. Treatment with antide completely abolished the neonatal rise in testosterone seen in control animals. The timing of the onset of the pubertal testosterone rise was not significantly affected by treatment; however, the subsequent pattern of circulating testosterone showed a tendency to decreased plasma concentrations in the neonatally treated group from weeks 25 to 42, relative to controls, and this difference was significant between 43 and 70 weeks. This was associated with a similar depression in bioactive LH concentrations around this time. Thereafter, the testosterone concentrations were similar between treated and control groups. There was no effect of treatment on growth, based on sequential body weight data. At 20 months the animals underwent behaviour tests with ovariectomized females. During these encounters, males showed the full panoply of normal sexual behaviours, with response to female proceptivity, tongue flicking, sustainable penile erections, mounts with pelvic thrusting, intromissions and intravaginal ejaculations. No significant differences were observed for any of these parameters between the control and treated animals. No changes in aggressive behaviours between groups were evident. These results show that blockade of the postnatal rise in testosterone in the male marmoset monkey may result in attenuation of the pubertal rise in testosterone but is without major effect on adult basal testosterone concentrations or reproductive behaviour. Journal of Endocrinology (1994) 141, 439–447

Relationships between metabolic endocrine systems and voluntary feed intake in Merino sheep fed a high salt diet

2007 ◽  
Vol 47 (5) ◽  
pp. 544 ◽  
Author(s):  
Dominique Blache ◽  
Micaela J. Grandison ◽  
David G. Masters ◽  
Robyn A. Dynes ◽  
Margaret A. Blackberry ◽  
...  
Keyword(s):  
Feed Intake ◽  
Salt Intake ◽  
Control Diet ◽  
Plasma Concentrations ◽  
High Salt ◽  
High Salt Diet ◽  
Salt Diet ◽  
Voluntary Feed Intake ◽  
High Salt Intake ◽  
Ad Libitum

Grazing saltbush reduces productivity in sheep mostly because the high salt intake decreases feed intake and challenges the metabolism of the animal. However, little is known of the effect of salt load on the endocrine control systems that regulate voluntary feed intake and metabolism. Plasma concentrations of leptin, insulin and cortisol and blood glucose were monitored in wethers fed for 2 weeks with either a control diet (adequate salt) fed ad libitum, a high salt diet (20% of dry matter) fed ad libitum or a group fed the control diet with an intake restricted to that of the high salt ad libitum group (control pair-fed). High salt intakes reduced voluntary feed intake within 1 day and circulating concentrations of insulin and glucose within 2 weeks. Liveweight and leptin concentrations were not specifically affected by the high intake of salt but decreased in response to the decrease in intake. Cortisol secretion was not affected. Although salt intake had a specific effect on insulin and glucose (over and above the effect of reduced feed intake alone), the reduction in insulin would be expected to increase rather than decrease appetite and feed intake. Therefore, insulin, leptin and cortisol do not appear to play major roles in the control of feed intake in sheep consuming high levels of salt.

scholarly journals Behavioral and Steroidogenic Pharmacology of Phenyl Ring Substituted Etomidate Analogs in Rats

2019 ◽  
Author(s):  
Megan McGrath ◽  
Aissa Hofmann ◽  
Douglas Raines
Keyword(s):  
Gabaa Receptor ◽  
Cushing’S Syndrome ◽  
Phenyl Ring ◽  
Plasma Concentrations ◽  
Plasma Corticosterone ◽  
Cushing's Syndrome ◽  
Plasma Testosterone ◽  
Control Group ◽  
General Anesthetic ◽  
Androgenic Steroids

Abstract Background: Cushing’s syndrome is an endocrine disorder characterized by the overproduction of adrenocortical steroids and associated with significant morbidity. Steroidogenesis enzyme inhibitors are the mainstays of pharmacological treatment. Unfortunately, they produce side effects that limit dosing, efficacy, and patient tolerability. Among the most potent inhibitors is the general anesthetic etomidate whose GABAA receptor-mediated sedative-hypnotic actions restrict use. In this study, we defined the sedative-hypnotic and steroidogenesis inhibiting actions of etomidate and four phenyl-ring substituted etomidate analogs (dimethoxy-etomidate, isopropoxy-etomidate, naphthalene-etomidate, and naphthalene(2)-etomidate) that possess negligible GABAA receptor modulatory activities. Methods: In the first set of experiments, male Sprague-Dawley rats were assessed for loss of righting reflexes (LoRR) after receiving intravenous boluses of either etomidate (1 mg/kg) or an etomidate analog (40 mg/kg). In the second set of experiments, rats were assessed for LoRR and their abilities to produce adrenocortical and androgenic steroids after receiving 2-hr infusions (0.5 mg kg-1min-1) of either etomidate or an etomidate analog. Results: All rats that received etomidate boluses or infusions had LoRR that persisted for minutes or hours, respectively. In contrast, no rat that received an etomidate analog had LoRR. Compared to rats in the vehicle control group, rats that received etomidate analog infusions had plasma corticosterone and aldosterone concentrations that were reduced by 80 – 84% and 68 – 94%, respectively. Rats that received etomidate infusions had plasma corticosterone and aldosterone concentrations that were also significantly reduced (by 92% and 96%, respectively). Rats that received etomidate or isopropoxy-etomidate had significant reductions (90% and 57%, respectively) in plasma testosterone concentrations whereas those that received naphthalene-etomidate had significant increases (1,400%) in plasma dehydroepiandrosterone concentrations. Neither etomidate nor any etomidate analog significantly affected plasma androstenedione and dihydrotestosterone concentrations. Conclusions: Our studies demonstrate that the four phenyl-ring substituted etomidate analogs form a novel class of compounds that are devoid of sedative-hypnotic activities and suppress plasma concentrations of adrenocortical steroids but vary in their effects on plasma concentrations of androgenic steroids. They provide a proof-of-concept for the development of non-sedating etomidate analogs to treat Cushing’s syndrome and other pathologies whose clinical courses may be improved by altering steroid biosynthesis.

scholarly journals Effects of deslorelin acetate on plasma testosterone concentrations in captive yellow-bellied sliders (Trachemys scripta sp.)

2017 ◽  
Vol 65 (3) ◽  
pp. 440-445 ◽  
Author(s):  
Romain Potier ◽  
Emma Monge ◽  
Tatiana Loucachevsky ◽  
Robert Hermes ◽  
Frank Göritz ◽  
...  
Keyword(s):  
Treatment Group ◽  
Anterior Pituitary ◽  
Native Species ◽  
Plasma Concentrations ◽  
Trachemys Scripta ◽  
Plasma Testosterone ◽  
Control Group ◽  
Captive Population ◽  
Freshwater Turtles ◽  
Contraceptive Effect

In Europe, the yellow-bellied slider (Trachemys scripta sp.) is a non-native species in competition with native freshwater turtles. Research on contraception could be useful to control the captive population. Identifying a method of contraception in chelonians would potentially help to control aggression in other chelonian species. The objective of the current study was to evaluate the effects of a single 4.7-mg deslorelin acetate implant on plasma testosterone concentrations in yellow-bellied sliders (Trachemys scripta sp.). Eleven adult male yellow-bellied sliders were used for the study. Males from the treatment group (n = 6) received a 4.7-mg deslorelin acetate implant, whereas males from the control group (n = 5) did not receive any treatment. All individuals were housed under the same environmental conditions. Testosterone plasma concentrations of the control group and the treatment group were measured at six time points (T0–T6) between April and September. No difference between the control group and the deslorelin treatment group was observed at T0, T2, T3, T4, T5 or T6. However, mean plasma testosterone concentration was significantly higher in the treatment group than in the control group at T1. This suggests that treatment with a 4.7-mg deslorelin acetate implant has a transient stimulatory effect on the anterior pituitary in yellowbellied sliders without a negative feedback on testosterone production. Further studies with a higher dosage of deslorelin acetate are needed to draw conclusions on its contraceptive effect.

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