Seasonal Variation In Weight Research Articles

Ultrastructure and histochemistry of the male reproductive system of the genus Callinectes Stimpson, 1860 (Brachyura: Portunidae).

We described the ultrastructure and histochemistry of the reproductive system of five Callinectes species, and evaluate the seasonal variation in weight of the reproductive system and hepatopancreas by comparing annual changes of somatic indices. The somatic indices changed little throughout the year. In Callinectes, spermatogenesis occurs inside the lobular testes and, within each lobule, the cells are at the same developmental stage. Spermatogenesis and spermiogenesis follow the same development pattern in all Callinectes studied. Mature spermatozoa are released into the seminiferous ducts through the collecting ducts. Cells of the vas deferens are secretory as evidenced by rough endoplasmic reticulum, Golgi complex, and secretory vesicles that produce the seminal fluid. The anterior vas deferens shows two portions: proximal and distal. In proximal portion (AVDp), spermatozoa are clustered and embedded in an electron-dense, basophilic glycoproteinaceous secretion Type I. In the distal portion (AVDd), the spermatophore wall is formed by incorporation of a less electron-dense glycoproteinaceous secretion Type II. The secretion Type I change to an acid polysaccharide-rich matrix that separates the spermatophores from each other. The median vas deferens (MVD) stores the spermatophores and produces the granular glycoproteinaceous seminal fluid. The posterior vas deferens (PVD) has few spermatophores. Its epithelium has many mitochondria and the PVD seminal fluid changes into a liquid and homogeneous glycoprotein. Many outpocketings in the PVD and MVD help to increase the fluid production. Overall, the reproductive pattern of Callinectes is similar to other species that produce sperm plugs. The secretions of AVD, MVD, and PVD are responsible for the polymerization that forms the solid, waxy plug in the seminal receptacle. The traits identified here are common to all Portunidae species studied so far.

Seasonal weight changes in laboratory ferrets.

Ferrets (Mustela putorius furo) are a valuable animal model used in biomedical research. Like many animals, ferrets undergo significant variation in body weight seasonally, affected by photoperiod, and these variations complicate the use weight as an indicator of health status. To overcome this requires a better understanding of these seasonal weight changes. We provide a normative weight data set for the female ferret accounting for seasonal changes, and also investigate the effect of fluid regulation on weight change. Female ferrets (n = 39) underwent behavioural testing from May 2017 to August 2019 and were weighed daily, while housed in an animal care facility with controlled light exposure. In the winter (October to March), animals experienced 10 hours of light and 14 hours of dark, while in summer (March to October), this contingency was reversed. Individual animals varied in their body weight from approximately 700 to 1200 g. However, weights fluctuated with light cycle, with animals losing weight in summer, and gaining weight in winter such that they fluctuated between approximately 80% and 120% of their long-term average. Ferrets were weighed as part of their health assessment while experiencing water regulation for behavioural training. Water regulation superimposed additional weight changes on these seasonal fluctuations, with weight loss during the 5-day water regulation period being greater in summer than winter. Analysing the data with a Generalised Linear Model confirmed that the percentage decrease in weight per week was relatively constant throughout the summer months, while the percentage increase in body weight per week in winter decreased through the season. Finally, we noted that the timing of oestrus was reliably triggered by the increase in day length in spring. These data establish a normative benchmark for seasonal weight variation in female ferrets that can be incorporated into the health assessment of an animal’s condition.

Study of lipid reserves in Liolaemus koslowskyi (Squamata: Liolaemidae): reproductive and ecological implications.

In reptiles, many lipid reserve structures were recognized, and different patterns of storage and utilization of lipids have been identified. In this study, a population of Liolaemus koslowskyi was studied to analyze the diversity and functioning of the lipid reserve structures. The specific objectives were to identify the main lipid reserve structures, and to describe their seasonal patterns; to study sexual and seasonal variations of the reserve structures; and to analyze the relation between seasonal patterns of such reserves with the sexual cycle and other biological aspects. Individuals of both sexes collected at five different times of the year were analyzed. The abdominal fat bodies, livers, tails, fat deposits of the lateral folds of the neck, the fat bodies of the axillary region and gonads were weighted. The fat content of livers, tails and neck fat reserves were determined through the extraction in a Soxhlet device. The volume of the ovaries, oviductal oocytes and testicles, and the average surface and thickness of the epididymides were estimated. The abdominal fat bodies and the tail-extracted fats were the main lipid reserves. In general, females showed higher lipid contents, and significant seasonal variations in weight and lipid content in both sex were found, while seasonal variations in the liver fresh weight and liver fat content were found only in males. The axillar and neck fats deposits probably function as auxiliary reserves, and the caudal autotomy did not significantly affect tail fat content. The sexual cycles were synchronic in both sexes.

Seasonal weight variation patterns in seven countries located in northern and southern hemispheres.

The digital revolution of information and technology in late 20th century has led to emergence of devices that help people monitor their weight in a long-term manner. Investigation of population-level variations of body mass using smart connected weight scales enabled the health coaches acquire deeper insights about the models of people's behavior as a function of time. Typically, body mass varies when the seasons change. That is, during the warmer seasons people's body mass tend to decrease while in colder seasons it usually moves up. In this paper we study the seasonal variations of body mass in seven countries by utilization of linear regression. Deviation of monthly weight values from the starting point of astronomical years (beginning of spring) were modeled by fitting orthogonal polynomials in each country. The distinction of weight variations in southern and northern hemispheres were then investigated. The studied population involves 6429 anonymous weight scale users from:(1) Australia, (2) Brazil, (3) France, (4) Germany, (5) Great Britain, (6) Japan, and (7) United States of America. The results suggest that there are statistically significant differences between the models of weight variation in southern and northern hemispheres. In both northern and southern hemispheres the lowest weight values were observed in the summer. However, the highest weight values were noticed in the winter and in the spring for northern and southern hemispheres, respectively.

SIRT1 Polymorphisms Associate with Seasonal Weight Variation, Depressive Disorders, and Diastolic Blood Pressure in the General Population.

SIRT1 polymorphisms have previously been associated with depressive and anxiety disorders. We aimed at confirming these earlier findings and extending the analyses to seasonal variations in mood and behavior. Three tag single-nucleotide polymorphisms (SNPs) were selected to capture the common variation in the SIRT1 gene. 5910 individuals (with blood sample, diagnostic interview, self-report of on seasonal changes in mood and behavior) were selected from a representative Finnish nationwide population-based sample. Logistic and linear regression models were used to analyze the associations between the SNPs and depressive and anxiety disorders, metabolic syndrome (EGIR criteria) and its components, and health examination measurements, Homeostasis Model Assessments, and diagnoses of type 2 and type 1 diabetes. SIRT1 rs2273773 showed evidence of association with seasonal variation in weight (C-allele, OR = 0.85, 95% CI = 0.76–0.95, p = 0.005). In addition, our study gave further support for the association of SIRT1 gene with depressive disorders (rs3758391) and diastolic blood pressure (rs2273773).

Creation and validation of a novel body condition scoring method for the magellanic penguin (Spheniscus magellanicus) in the zoo setting.

This research aims to validate a novel, visual body scoring system created for the Magellanic penguin (Spheniscus magellanicus) suitable for the zoo practitioner. Magellanics go through marked seasonal fluctuations in body mass gains and losses. A standardized multi-variable visual body condition guide may provide a more sensitive and objective assessment tool compared to the previously used single variable method. Accurate body condition scores paired with seasonal weight variation measurements give veterinary and keeper staff a clearer understanding of an individual's nutritional status. San Francisco Zoo staff previously used a nine-point body condition scale based on the classic bird standard of a single point of keel palpation with the bird restrained in hand, with no standard measure of reference assigned to each scoring category. We created a novel, visual body condition scoring system that does not require restraint to assesses subcutaneous fat and muscle at seven body landmarks using illustrations and descriptive terms. The scores range from one, the least robust or under-conditioned, to five, the most robust, or over-conditioned. The ratio of body weight to wing length was used as a "gold standard" index of body condition and compared to both the novel multi-variable and previously used single-variable body condition scores. The novel multi-variable scale showed improved agreement with weight:wing ratio compared to the single-variable scale, demonstrating greater accuracy, and reliability when a trained assessor uses the multi-variable body condition scoring system. Zoo staff may use this tool to manage both the colony and the individual to assist in seasonally appropriate Magellanic penguin nutrition assessment.

Seasonal Variation in Thyroid Gland of the Female Bat, <i>Taphozous Kachhensis</i> (Dobson) During Pregnancy

The aim of present study was to compare the changes in thyroid gland during the reproductive cycle of the female bat Taphozous kachhensis . The thyroid gland of the bat was studied morphometrically and histologically, it showed marked seasonal variation in weight, quantity of colloid, epithelial cell height and plasma concentration of thyroid hormones. The thyroid gland was a symmetrical, bilobed, and located on the lateral side of the trachea, between the first and the third tracheal rings, connected by an isthmus. The mean weight of the noted lobes was (2.240±0.121) mg, (2.88±0.05) mg and (2.704±0.067) mg, during early pregnancy, mid pregnancy and late pregnancy respectively. The thyroid hormone showed marked seasonal variations. During early pregnancy there was rise in the level of TSH (1.7 ng/mL) but the slight decrease in the level of T3 (54 ng/mL) and T4 (2.9 ng/mL) was noticed. The level of TSH and T4 was decreases during mid pregnancy but the increase in the level of T3 was noticed and it was highest as compare to other stages and it is found to be 1.4 ng/mL, 1.5 ng/mL, 69 ng/mL respectively. During late pregnancy, TSH and T3 concentration decreases but the increase in the level of T4 was observed and it was found to be 0.9 ng/mL, 60 ng/mL, 2.9 ng/mL respectively. The diameter of colloid in small, medium and large follicle during early pregnancy and late pregnancy were 28 µm, 56 µm, 96 µm and 36 µm, 60 µm, 72 µm respectively. The epithelial cell heights of small, medium and large size follicles during early pregnancy and late pregnancy were 3.6 µm, 4 µm, 8 µm and 4 µm, 8 µm, 8 µm respectively.

Influence of seasonal variation in mood and behavior on cognitive test performance among young adults

Background: Seasonal variations in mood and behavior are common among the general population and may have a deteriorating effect on cognitive functions. Aims: In this study the effect of seasonal affective disorder (SAD-like symptoms) on cognitive test performance were evaluated in more detail. Methods: The data were derived from the study Mental Health in Early Adulthood in Finland. Participants (n = 481) filled in a modified Seasonal Pattern Assessment Questionnaire (SPAQ) and performed cognitive tests in verbal and visual skills, attention and general intelligence. Results: SAD-like symptoms, especially regarding the seasonal variations in weight and appetite, had a significant effect on working memory (Digit Span Backward, P = 0.008) and auditory attention and short-term memory (Digit Span Forward, P = 0.004). The seasonal variations in sleep duration and mood had an effect on auditory attention and short-term memory (Digit Span Forward, P = 0.02 and P = 0.0002, respectively). The seasonal variations in social activity and energy level had no effect. Conclusions: Seasonal changes in mood, appetite and weight have an impairing effect on auditory attention and processing speed. If performance tests are not to repeated in different seasons, attention needs to be given to the most appropriate season in which to test.

Secretory Processes in Follicular Cells of the Thyroid Gland of the Indian Sheath-tailed Bat, Taphozous longimanus (Hardwicke): A Ultrastructural Study

The aim of present study was to compare the ultrastructural changes in thyroid gland during different phases of the reproductive cycle of Taphozous longimanus. Thyroid gland shows marked seasonal variation in weight, quantity of colloid and follicular epithelial height and ultrastructural characteristics. During estrus, the thyroid gland is composed of small and medium follicles. The follicular cells contain mitochondria with lamellar cristae, well developed rough endoplasmic reticulum and Golgi complex and large number of dense bodies. During early and mid-pregnancy, thyroid gland composed mostly of small follicles. The characteristics of the follicular cells are the well developed rough endoplasmic reticulum, Golgi apparatus and numerous dense granules. Colloid droplets are observed in the cytoplasm. These findings are associated with a high rate of thyroid activity. Towards the end of pregnancy, the large follicles are noticed in the thyroid gland in addition to medium sized follicles. The follicular cells of large follicles contain inconspicuous Golgi apparatus, a few mitochondria and rudimentary rough endoplasmic reticulum, suggesting a low rate of thyroid activity. During lactation, the thyroid gland as in estrus is composed of medium to small sized follicles. The ultrastructural features of thyroid follicular cells indicate that these cells are synthetically very active.

Seasonal variation in weight and biochemical composition of the Pacific oyster, Crassostrea gigas in relation to the gametogenic cycle and environmental conditions of the Bizert lagoon, Tunisia

Seasonal variations in biochemical composition of the bivalve Crassostrea gigas were studied from February 2002 until January 2003 in the Bizert lagoon in relation to environmental conditions and reproductive events. Separate analyses were made of gonad-visceral mass. The gametogenic cycle comprised tow phases: gametogenesis including ripeness and spawning (March–September) and sexual repose during the rest of the year. The C. gigas in the Bizert lagoon showed a clear cycle of energy storage and utilization. Total biochemical composition was about 6.50% ± 3.01 of dry weight in glycogen, 14.34% ± 3.60 of dry weight in protein and 6.67% ± 1.34 of dry weight in lipids. Lipid and glycogen concentrations in the gonad-visceral mass were inversely related: maximum concentrations of glycogen occurred between December and February and corresponded with minimum concentrations of lipids. High glycogen contents recorded in winter supported the processes of gamatogenesis and then decreased progressively to attain low values at maturity and during summer corresponded to the first emission of gametes (June) and the beginning of total spawning, however lipids are accumulated in gonads during the period of maximum ripeness (spring) and decrease in summer. During autumn, the increase of total fatty acids values appeared to be related to the available food in association with an increase in the chlorophyll a concentrations. Protein contents show many variations throughout the year. High protein levels occurred in May and in July which corresponded to oocyte maturation and then decreased in late summer (beginning of total spawning). At the expense of the available food in autumn, protein concentrations increase again to assure recovery of the tissue weight of the bivalve, which induced an increase in the condition indices values.

Post‐mortem examination of New Zealand pigeons (Hemiphaga novaeseelandiae) from the Auckland area

In a large sample of New Zealand pigeons (Hemiphaga novaeseelandiae) found dead in the wider Auckland region, New Zealand, the sex ratio was 1.7:1 in favour of females. Adult males had slightly but significantly shorter bills and longer wings than females, but there was no significant difference between the sexes for tarsus and tail length. Adults weighed 420–780 g, with an average of 638 g for males and 596 g for females (not significantly different). There was little seasonal variation in weight, but fat score was highest on average in autumn and lowest in summer. In adults, testes were often enlarged from September to February with a peak in October, and ovaries were often enlarged from August to January, suggesting that birds laid their eggs between August and September and January and February. This breeding period is long but still seasonal. There was a long season of primary moult (October‐May) with a post‐breeding peak (February‐April), and an absence of moult in winter. Tail moult was confined to late summer and autumn (February‐April).

The relationship between obesity and seasonal variation in body weight among elementary school children in Tokyo

Typical patterns of seasonal variation in body weight among Japanese children involve increases during the fall and/or winter and decreases during the summer. However, atypical variations, namely, increases in weight during the summer, have been reported for obese children. The present study examines whether weight gain during the summer (i.e., July through September) is a possible cause of obesity. We examined seasonal changes in weight for 446 elementary school children in Tokyo in six waves between 1972 and 2004. Weight was measured monthly for 6 years in each child and was evaluated by means of time-series analysis. Overall, significant seasonal variations in weight were found in 86% of the children, most of which were typical (i.e., decreases during the summer and increases during the fall, winter, and/or early spring). On the other hand, weight gain in the summer was observed exclusively among obese children. Children whose weight increased during the summer holiday spent most of their time comfortably indoors because of air conditioners, which became popular in 1970s. A possible explanation of the observed weight gain during the summer seems to be changes in life style associated with the use of air conditioning, concomitant with insufficient physical exercise and excessive consumption of food and drink, which could disturb the rhythms of seasonal weight changes and lead to obesity.

Seasonal variation in weight and biochemical composition of the tissues of Ruditapes decussatus in relation to the gametogenic cycle

Seasonal variations in the body weight and biochemical composition of the bivalve Ruditapes decussatus were studied over a period of 15 months. Separate analyses were made of foot, mantle edge, siphons, gills, adductor muscle and gonad-visceral mass. Variations in weight, body growth, gonad growth and spawning depended on environmental conditions, especially food availability. The gametogenic cycle comprised two phases: a resting phase (November–December) and gametogenesis, including ripeness and spawning, during the rest of the year. Gametogenesis usually took place during the spring, and spawning in summer (June–August). The highest variation in biochemical composition was largely attributable to a change in the glycogen content (average 14.7%±5.1 S.D. of dry weight). Protein (48.1%±1.8) and lipid contents (5.6%±0.6) remained relatively constant throughout the year. Adductor muscle, foot and siphons contained mainly proteins (67.8%, 51.2% and 65.8% of the dry tissue weight, respectively) and gonad-visceral mass and gills contained the highest amount of lipids (≈7%). The gonad-visceral mass showed the largest variations in all components during the gametogenic cycle. Lipid and glycogen concentrations in the gonad-visceral mass were inversely related: maximum concentrations of glycogen occurred during the resting phase or initial gametogenesis and corresponded with minimum concentrations of lipids, and minimum concentrations of glycogen occurred at maturity when lipids reached maximum concentrations. The gonad-visceral mass contained lower amounts of proteins (<40%) than the other body parts. Variations in total fatty acid content in neutral and polar lipids of the gonad-visceral mass followed a seasonal cycle related to the gametogenic cycle, with increases during the period of maximum ripeness and decreases during spawnings. Maximal contents of polyunsaturated fatty acids, especially in the polar lipids corresponded with oocyte maturation and minimal contents with the post-spawning period. However, variations in the neutral lipids appeared to be related to the available food, in association with an increase in the chlorophyll a concentration.

Seasonal changes in thyroid activity in the female sheath-tailed bat, Taphozous longimanus (Chiroptera: Emballonuridae).

The present study was designed to investigate changes in thyroid activity during the reproductive cycle in Taphozous longimanus. Thyroid gland showed marked seasonal variation in weight and secretory activity. It was inactive in quiescence and early to mid-winter dormancy and active during recrudescence and breeding period during late winter dormancy. The serum 3,5,3'-triiodothyronine (T3) and thyroxine (T4) concentrations showed significant variation and closely coincided with thyroid activity. The T3 and T4 concentrations were higher in recrudescence, late winter dormancy and minimum in quiescence and initial stages of first pregnancy. The body weight (r = 0.56), ovary weight (r = 0.73), and thyroid weight (r = 0.70) showed correlation with each other and with T3 and T4 concentrations. The correlation between body weight, thyroid weight and T3 and T4 concentrations in non-pregnant bats was higher when compared with pregnant bats. The T3 and T4 levels remained low during the initial stages of development in first pregnancy when compared with the initial stages of second pregnancy. The scant food supply and low levels of T3 and T4 and low temperature during initial stages of first pregnancy might be responsible for differential rate of fetal development in two successive pregnancies in T. longimanus.

Changes in the thyroid gland during the reproductive cycle of the male vespertilionid bat, Scotophilus heathi

The aim of present study was to compare the changes in thyroid gland with the reproductive cycle of S. heathi. Thyroid showed marked seasonal variation in weight, quantity of colloid and follicular epithelial height, suggesting the thyroid gland to be inactive during quiescence and winter dormancy and active during the time of recrudescence and breeding similarly to the testicular cycle. Plasma thyroxin (T4) concentration showed a significant seasonal change with high concentration during breeding and post-breeding and low concentration during quiescence. However, the T4 concentration increased from breeding to post-breeding phase, when the testes weight was declining. It is suggested that in S. heathi the positive correlation between thyroid and testicular cycles occurs only during the phases of the reproductive cycle when the body weight and testicular activity are also closely correlated.

Abstracts

To assess the contention of many people with diabetes that they gain weight in winter and lose weight in summer we have investigated 10836 weights recorded during all the routine clinic visits of 3119 patients (age 18-93 years, 51.7% male, 31.2% diet controlled, 32.8% on oral hypoglycaemic agents, 36.0% on insulin)between February 1992 and July 1995. Efforts to fit a sinewaveform to the weight data (raw and log transformed) plotted against time of the year were unsuccessful and a smoothed mean weight plotted over time closely matched the overall mean. Linear modelling was applied to data from each clinic visit relating log transformed weight to age, gender, diabetes therapy, random plasma glucose and the interactions of these terms. The best fitting model accounted for 23.3% of the observed variability with gender, diabetes therapy, age, age squared and interactions between these as the key factors; interpatient variation accounted for over 95% of the residual variance from the model. Addition of time of year as a continuous variable or as 12 discrete factors (months) did not improve the fit of the model. We conclude that there is no general tendency to seasonal weight variation in people with diabetes.

Inter-individual and seasonal weight variation in rural Nepali women

Changes in body weight were examined for non-pregnant women in rural Nepal, using 183 anthropometric measures between the early winter and monsoon seasons in 1982, 1982-83, 1990-91 and 1993. The women gained weight when work loads decreased after the monsoon, but despite substantial changes in total energy expenditure, which were out of phase with changes in food intake, seasonal changes were small, averaging only up to 2.6% of initial body weight. There were notable differences between individual women, changes in body weight ranging from -5.6 kg to 4.8 kg. Weight change was examined with respect to lactation status, age, body mass index, mid upper arm circumference and skinfolds as well as total energy expenditure and intake. Nonlactating women, very thin women and women aged under 25 years gained more weight than their counterparts, both before and after the monsoon. Data for a sub-sample in 1982-83 indicated that women who maintained high physical activity levels throughout the year were less prone to weight loss than women whose activity fluctuated between seasons. Initial energy reserves, age-related maturation factors, levels of physical activity and energy intake combine to produce the notable inter-individual variation in body weight changes observed in this population.

Seasonal variation in weight, body measurements and condition of free-living Teal

The weights and measurements of almost 7000 Teal captured in Abberton Reservoir, Essex during 1969–85 were analysed. Teal showed significant differences between the first year and adult birds and between males and females in tarsus and wing length, but significant differences only between the sexes in skull length. Weights were corrected for body size using wing length to give a condition index. The index of condition increased in all age and sex classes from September to reach maximum values late in the year, before falling to lowest levels in February. Female birds show more marked responses by the reduction in January condition index to hard weather than males and, indeed, the proportion of females caught at Abberton significantly declines with increasing severity of weather conditions. The significance of these sex related responses are discussed in the light of known features of the ecology of the species.

Patterns of seasonal weight variation in waders on the wash

Analysis of weight variation, based on monthly mean weights for ten wader species occurring on the Wash demonstrating the patterns of season weight variation. For each species the trends are interpreted in terms of adaptations and responses to specific life cycle events and potential feeding difficulties which arise from winter environmental conditions.

Seasonal variation in weight and biochemical composition of the tissues of the queen scallop,Chlamys opercularis, from the Clyde Sea area

A number of studies exist on the seasonal cycles of body weight and tissue biochemistry of several species of bivalve from the Clyde Sea area (Ansell &amp; Trevallion, 1967; Ansell, 1974,et seq), including two members of the Pectinidae, namelyChlamys septemradiata(Müller) (Ansell, 1974) andPecten maximusL. (Comely, 1974). Some comparative data are available forChlamys opercularis(L.) from Manx waters (Soemodihardjo, 1974) and forP. maximusfrom the north Irish Sea (Stanley, 1967).