Does testosterone or coloration affect growth rates of adult males of the lizard Psammodromus algirus?

2000 ◽  
Vol 78 (8) ◽  
pp. 1463-1467 ◽  
Author(s):  
Alfredo Salvador ◽  
José P Veiga
Keyword(s):  
Body Mass ◽  
Breeding Season ◽  
Mass Gain ◽  
Reproductive Period ◽  
The Body ◽  
Adult Males ◽  
Psammodromus Algirus ◽  
Ornamental Traits ◽  
Breeding Coloration

Elevation of circulating testosterone levels during the breeding season stimulates the development of breeding coloration and favors traits that maximize reproductive success, but it may have several costs. Retardation of growth by testosterone has been proposed as one of these costs to males of long-lived species. We examine the results of a field experiment on the short-term (within the breeding season) and long-term (1 year) effects of heightening levels of testosterone on the growth of males of the lacertid lizard Psammodromus algirus. Testosterone did not affect the mass gain of males during the reproductive period or between years. The between-years increase in snout-vent length in testosterone-supplemented males tended to be less than in control individuals. Within-season individual mass gain was mainly determined by body mass at emergence: the lower the body mass the higher the mass gain. Our results do not support the idea that the production of ornamental traits limits growth, as the negative correlation between degree of head coloration and mass gain disappeared when body mass was controlled for.

CHARACTERISTICS OF POST-FLIGHT MUSCLE STRENGTH AND VELOCITY DYNAMICS IN COSMONAUTS AS A FUNCTION OF WEIGHT LOADING DURING LONG-TERM SPACE MISSIONS

2020 ◽  
Vol 54 (5) ◽  
pp. 23-28
Author(s):  
E.V. Fomina ◽  
◽  
T.B. Kukoba ◽  
Keyword(s):  
Muscle Strength ◽  
Body Mass ◽  
Flight Muscle ◽  
Space Mission ◽  
The Body ◽  
Maximum Strength ◽  
Training Device ◽  
Leg Muscle ◽  
Weight Loading

Testing of 25 cosmonauts showed that the amount of resistance training weight loading in long-term space mission influences dynamics of the leg-muscle strength and velocity recovery. On Earth, the loads equal from 70 to 130 % of the body mass is sufficient for keeping up endurance and maximum strength moments of shin and thigh muscles. In the group of cosmonauts who had not used the strength training device or chosen loads less than 30 % of the body mass the leg-muscle maximum strength and thigh endurance were decreased substantially on day 4 of return and all the more by day 15 back on Earth.

Hydration status of Greco-Roman wrestlers in an authentic precompetition situation

2013 ◽  
Vol 38 (6) ◽  
pp. 621-625 ◽  
Author(s):  
Vahur Ööpik ◽  
Saima Timpmann ◽  
Andres Burk ◽  
Innar Hannus
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Urine Osmolality ◽  
Mass Gain ◽  
The Body ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Greco Roman ◽  
Reduced Body ◽  
Body Mass Gain

We assessed the urinary indexes of hydration status of Greco-Roman wrestlers in an authentic precompetition situation at the time of official weigh-in (OWI). A total of 51 of 89 wrestlers competing in the Estonian Championship in 2009 donated a urine sample. Questionnaire responses revealed that 27 wrestlers (body mass losers (BMLs)) reduced body mass before the competition, whereas 24 wrestlers (those who do not lose body mass (n-BMLs)) did not. In 42 wrestlers, values of urine specific gravity ≥1.020 and urine osmolality ≥700 mOsmol·kg−1 revealed a hypohydrated status. The prevalence of hypohydration in the BMLs (96%) was higher than in the n-BMLs (67%) (χ2 = 7.68; p < 0.05). The prevalence of serious hypohydration (urine specific gravity >1.030) was 5.3 times greater (χ2 = 8.32; p < 0.05) in the BMLs than in the n-BMLs. In the BMLs, the extent of body mass gain during the 16-h recovery (2.5 ± 1.2 kg) was associated (r = 0.764; p < 0.05) with self-reported precompetition body mass loss (4.3 ± 2.0 kg) and exceeded the body mass gain observed in the n-BMLs (0.7 ± 1.2 kg; p < 0.05). We conclude that hypohydration is prevalent among Greco-Roman wrestlers at the time of OWI. The prevalence of hypohydration and serious hypohydration is especially high among wrestlers who are accustomed to reducing body mass before competition. These results suggest that an effective rehydration strategy is needed for Olympic-style wrestlers, and that changes in wrestling rules should be considered to reduce the prevalence of harmful body mass management behaviours.

scholarly journals Effect of High Intensity Interval and Continuous Swimming Training on Body Mass Adiposity Level and Serum Parameters in High-Fat Diet Fed Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Guilherme L. da Rocha ◽  
Alex H. Crisp ◽  
Maria R. M. de Oliveira ◽  
Carlos A. da Silva ◽  
Jadson O. Silva ◽  
...  
Keyword(s):  
Body Mass ◽  
High Fat Diet ◽  
Interval Training ◽  
Mass Gain ◽  
The Body ◽  
Standard Diet ◽  
High Fat ◽  
Continuous Training ◽  
Body Mass Gain ◽  
Training Standard

This study aimed to investigate the effects of interval and continuous training on the body mass gain and adiposity levels of rats fed a high-fat diet. Forty-eight male Sprague-Dawley rats were randomly divided into two groups, standard diet and high-fat diet, and received their respective diets for a period of four weeks without exercise stimuli. After this period, the animals were randomly divided into six groups (n=8): control standard diet (CS), control high-fat diet (CH), continuous training standard diet (CTS), continuous training high-fat diet (CTH), interval training standard diet (ITS), and interval training high-fat diet (ITH). The interval and continuous training consisted of a swimming exercise performed over eight weeks. CH rats had greater body mass gain, sum of adipose tissues mass, and lower serum high density lipoprotein values than CS. The trained groups showed lower values of feed intake, caloric intake, body mass gain, and adiposity levels compared with the CH group. No significant differences were observed between the trained groups (CTS versus ITS and CTH versus ITH) on body mass gains and adiposity levels. In conclusion, both training methodologies were shown to be effective in controlling body mass gain and adiposity levels in high-fat diet fed rats.

Long-term survival, length of breeding season, and operational sex ratio in a boreal population of common frogs, Rana temporaria L.

1990 ◽  
Vol 68 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Johan Elmberg
Keyword(s):  
Sex Ratio ◽  
Breeding Season ◽  
Rana Temporaria ◽  
Return Rate ◽  
Operational Sex Ratio ◽  
Adult Males ◽  
Term Survival ◽  
Size Dependent ◽  
Survival Selection

A population of individually marked adult Rana temporaria was studied during the breeding season in 1979–1988 in east-central Sweden. Annual return rate averaged 31% (range 16–51%) in males and 16% (range 5–33%) in females. Return rate was not size dependent but increased with every successful previous hibernation, indicating an increased survival rate with age. Return rate was not correlated with winter harshness. Once adult, males had on average 1.5 (maximum 6) seasons with the possibility of reproducing. Corresponding values for females were 1.4 and 4. Mean length of the breeding season was 20 (SD = 2) days. Calling generally started at water temperatures below 3 °C. The lowest spawning temperature was 1 °C. Average temperatures at spawning onset and peak spawning were 5 and 6 °C, respectively. Large males tended to arrive earlier at the pond than small males. Males arrived earlier and stayed longer than did females. The overall population sex ratio was close to unity. The operational sex ratio (OSR) varied during the breeding season, averaging 0.54 (one female to two males). No male was observed to mate more than once per season. I argue that survival selection is more important to male lifetime mating success than is competition in the breeding pond (sexual selection as affected by OSR and length of the breeding season).

Maternal Thyroid Hormone Deficiency During Gestation and Lactation Alters Metabolic and Thyroid Programming of the Offspring in the Adult Stage

2019 ◽  
Vol 51 (06) ◽  
pp. 381-388 ◽  
Author(s):  
Jorge Tapia-Martínez ◽  
Alejandra Paola Torres-Manzo ◽  
Margarita Franco-Colín ◽  
Marisol Pineda-Reynoso ◽  
Edgar Cano-Europa
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Body Mass ◽  
Adult Life ◽  
Mass Gain ◽  
Hormone Deficiency ◽  
Body Mass Gain ◽  
Maternal Thyroid

AbstractEnvironmental stimuli during critical developmental stages establish long-term physiological and structural patterns that “program” health during adult life. Little is known about how alterations in hormonal supply might have consequences in metabolic and thyroid programming. This work aims to prove that alterations in the supply of thyroid hormones during gestation and lactation have long-term consequences in the metabolic and thyroid programming of the offspring. Female Wistar rats were divided into euthyroid, hypothyroid, and hypothyroid with 20 μg/day of s.c. thyroxine (T4), replacement wet nurses. Rats were mating, and after birth, pups were grouped according to their wet nurses group. Milk quality of wet nurses was assessed on days 7, 14, and 21. Body mass gain and energy intake of the offspring were monitored for 28 weeks after weaning. At sacrifice, we extracted and weighed their thyroid gland and adipose reserves, and collected blood to measure its metabolic and thyroid profiles. Hypothyroid wet nurses presented a persistent low quality of milk, while both male and female hypothyroid offspring presented lower body mass gain, higher blood glucose, dyslipidemia, hyperinsulinemia, and hyperleptinemia, as well as lower total adipose reserves, but higher visceral reserve, diminished T3 and T4 concentrations, and lower weight of thyroid gland. Thyroxine replacement prevented all changes in both wet nurses and pups. We conclude that maternal thyroid hormone deficiency during congenital and lactation stages alters the metabolic and thyroid programming of the offspring, while the reestablishment of maternal thyroid status during critical periods of development can prevent these alterations.

Seasonal-Variation in the Ranging Behavior of the Platypus (Ornithorhynchus-Anatinus) on the Goulburn River, Victoria

1995 ◽  
Vol 43 (2) ◽  
pp. 193 ◽  
Author(s):  
N Gust ◽  
K Handasyde
Keyword(s):  
Home Range ◽  
Breeding Season ◽  
Radio Telemetry ◽  
Activity Patterns ◽  
Water Levels ◽  
The Body ◽  
Breeding Period ◽  
Ranging Behavior ◽  
Adult Males ◽  
Temporal Separation

Radio-telemetry was used to study the effects of changing reproductive condition and water levels on the ranging behaviour and activity patterns of adult male platypuses in the Goulburn River, Victoria. Home-range size varied greatly between individuals, from 2 . 45 to 15 . 45 ha, but differences in the body weight of individuals did not account for this variability. There was no correlation between the number of burrows used by males and their body size or home-range length. Changing river levels or the animal's breeding condition did not appear to affect the duration of activity periods, which remained constant throughout the study. All radio-tracked animals foraged in a submerged backwater area during high-water conditions, suggesting that platypuses are opportunistic in their habitat usage and may avoid fast-flowing water if calmer areas are available. Although the home ranges of adult males overlapped extensively during the non-breeding period, there was evidence of spatial separation during the breeding season, when animals occupied separate core areas. In addition there appeared to be some temporal separation between adult males during the breeding season. During this period there was greater variation in the times at which animals emerged from their burrows, and some animals became diurnal.

Long-term trends in the body mass index and obesity risk in Estonia: an age–period–cohort approach

2020 ◽  
Vol 65 (6) ◽  
pp. 859-869
Author(s):  
Rainer Reile ◽  
Aleksei Baburin ◽  
Tatjana Veideman ◽  
Mall Leinsalu
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
The Body ◽  
Obesity Risk ◽  
Long Term Trends
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