圈养大熊猫幼仔的早期体重变化

大熊猫(Ailuropoda melanoleuca)幼仔快速生长发育是在进化过程中形成的有利于种群长期保存的生存策略(胡锦矗,2001).大熊猫幼仔的体重是衡量其生长发育的重要指标之一,也是调整圈养大熊猫饲养管理的重要参考依据.在圈养条件下,大熊猫幼仔在0和1年龄级的死亡率分别为12.89％和18.37％(赵素芬等,...     

中国林蛙生长发育参数与产油量关系的研究

为了能够直接通过外部形态特征判断中国林蛙的产油量,本文采用单因素回归和逐步回归分析方法,初步研究了黑龙江省中部地区中国林蛙(Raaa chensinensis David)雌体的体重、体长、前后肢长、卵重、年龄与产油量(左右输卵管重量之和)之间的关系。结果表明：产油量与体重、体长、前肢长、后肢长、卵重、年龄均存在正相关;产油量与体重和体长具有显著的正相关(r=0．930),其回归方程：Y=-0．566 0．016x1 0．072x2。因此,体重和体长可以作为判断产油量多少的重要指标。     

Mammalian reproductive strategies: A generalized relation of litter size to body size

Summary A generalized relationship of litter size to mammalian body size was predicted by a graph model. The model was used to generate hypotheses explaining specific features of variation in gestation time, relative litter weight, birth weight, and reproductive capacity. The predictions were tested by means of data from the literature.Mammals were assumed to maximize neonatal survival of offspring to the limits allowed by litter weight per female body weight. Gestation time correlated negatively with the foetal growth rate of relative litter weight. Gestation time did not correlate with the foetal growth rate of individual offspring.Relative litter weight correlated negatively with adult body weight. This relationship was explained by the higher assimilation rate per unit weight relative to metabolic rate in small mammals.Birth weight correlated positively with body weight. However, small mammals produce larger offspring than predicted by the linear relationship of birth weight to body weight in large mammals. There is obviously a minimum birth weight which cannot be decreased without special arrangements for parental care.The prediction of the relationship of litter size to body size was derived from the relations of relative litter weight and birth weight to body weight. In small mammals (less than 1 kg) litter the correlation was negative. When litter size was compared with body length, the correlation was positive in small mammals (less than 30 cm) and negative in large mammals. In both sets of data there was a negative overall correlation between litter size and body size.Reproductive capacity, defined as the number of offspring per season, correlated negatively with life-span.     

Independent effects of weight and mass on plantar flexor activity during walking: implications for their contributions to body support and forward propulsion.

The ankle plantar flexor muscles, gastrocnemius (Gas) and soleus (Sol), have been shown to play important roles in providing body support and forward propulsion during human walking. However, there has been disagreement about the relative contributions of Gas and Sol to these functional tasks. In this study, using independent manipulations of body weight and body mass, we examined the relative contribution of the individual plantar flexors to support and propulsion. We hypothesized that Gas and Sol contribute to body support, whereas Sol is the primary contributor to forward trunk propulsion. We tested this hypothesis by measuring muscle activity while experimentally manipulating body weight and mass by 1) decreasing body weight using a weight support system, 2) increasing body mass alone using a combination of equal added trunk load and weight support, and 3) increasing trunk loads (increasing body weight and mass). The rationale for this study was that muscles that provide body support would be sensitive to changes in body weight, whereas muscles that provide forward propulsion would be sensitive to changes in body mass. Gas activity increased with added loads and decreased with weight support but showed only a small increase relative to control trials when mass alone was increased. Sol activity showed a similar increase with added loads and with added mass alone and decreased in early stance with weight support. Therefore, we accepted the hypothesis that Sol and Gas contribute to body support, whereas Sol is the primary contributor to forward trunk propulsion.     

Changes in body composition and efficiency of food utilization for growth in young adult female rats before, during and after a period of food restriction.

Changes in body composition were studied in three groups of young adult female rats; the treatments were (1) ad libitum food intake to obtain normal growth, (2) restricted food intake to cause body weight loss, and (3) restricted followed by ad libitum food intake to obtain recovery of lost body weight. In each of the three groups of rats the percentage body water was linearly and negatively correlated with the percentage body fat, the weight of body water was linearly and positively correlated with the weight of body protein, and the ratio of the weight of body protein to water was relatively constant at 1:3.20 +/- 0.02 (mean +/- standard error). The percentage body water in the fat-free body was linearly and negatively correlated with fat-free body weight during normal growth between 109 and 334 g body weight but positively correlated during body weight loss and recovery. During recovery of body weight rats laid down more fat and less protein than during normal growth through the same body weight range and the percentage of digestible energy retained as body tissue was increased.     

Effects of semi-starvation on the total body composition and absorptive function of the small intestine of the young adult female rat.

Sixteen female rats aged about 80 days and with a mean body weight of 175 g were fed 40% of their ad libitum intake of a laboratory chow. They were killed and analysed for water, protein, lipid and ash after 9, 21-5, 30-2 and 38-8% of body weight had been lost. Compared to a control group of four animals, the 38-8% group lost 13 g or 34% of their protein. The animals in the 21-5, 30-2 and 38-8% groups lost 7-5 g or 87% of their lipid leaving only 1-1 g of lipid. The percentage protein in the body was little affected by body weight loss but lipid decreased from 5 to 1%. In another experiment with 26 rats of 205 g mean body weight and aged about 115 days, absorption rates by the small intestine were measured in vivo after variable weight losses between 0 and 39%. D(+)-Glucose uptake was increased by about 70% in those animals which had lost only 5% of body weight and this increased uptake was retained in those rats which had lost up to 39% of body weight. The absorption of L-leucine was not affected by the decline in body weight compared to the controls but relative to body weight, the ability of the intestine to absorb increased. In the same animals, the wet and dry weights of the small intestine declined slightly faster than body weight and the length of the small intestine tended to decrease slightly with increasing loss of body weight.     

Seasonal fluctuations of food intake and bodyweight in the dormouse Glis glis (author's transl)]

Cycles of body weight lasting a few weeks occurred in dormice fed ad libitum, throughout the year with the same food. The pattern of the fluctuations suggests an oscillation between an upper and a lower limit. When the lower limit is reached, compensatory mechanisms acting on the food intake are induced which cause an increase in body weight to the upper one; when this upper limit is reached, other mechanisms cause the body weight to decrease to the lower one. Thus, body weight and variations in food intake may well be controlled by the difference between the body weight and the limit it will reach. In a warm environment (23-25 degrees C) these fluctuations are smaller than in the cold (5-6 degrees C). They are also smaller during summer than during winter in animals placed in natural climatic conditions. In summer, the body weight stays near the upper limit; in this season, as in the warm environment, the lower limit approaches the upper one. Thus, the main circannual variation of body weight regulation in dormice may be the elevation during summer of the lower body weight limit.     

Variation in reproductive traits in European passerines in relation to nesting site: allometric scaling to body weight or adaptive variation?

Summary The relationships between different reproductive traits and body weight, in relation to nesting site, were studied in European passerines. Body weight explains a significant proportion of the variance in clutch size, egg weight, clutch mass, and incubation period. Whereas clutch size decreases, the other three traits increase with body weight. Even though both clutch mass and clutch size are related to body size, for a given body weight, concealed nesters lay a larger clutch and a greater clutch mass than open-nesters.     

Feeding enrichment and body weight in captive chimpanzees

Although positive behavioral consequences have been attributed to feeding enrichment, physiological changes may also occur. In this study, the body weight records of a large chimpanzee colony were reviewed to determine if body weight was affected by the implementation of a daily enrichment program, including food items offered three to four times per week. Comparing the mean body weight by age groups indicated that the weight of female chimpanzees was significantly greater after feeding enrichment but that male body weight did not differ.     

Modeling the relationship between body weight and energy intake: A molecular diffusion-based approach

ABSTRACT: BACKGROUND: Body weight is at least partly controlled by the choices made by a human in response to external stimuli. Changes in body weight are mainly caused by energy intake. By analyzing the mechanisms involved in food intake, we considered that molecular diffusion plays an important role in body weight changes. We propose a model based on Fick's second law of diffusion to simulate the relationship between energy intake and body weight. RESULTS: This model was applied to food intake and body weight data recorded in humans; the model showed a good fit to the experimental data. This model was also effective in predicting future body weight. CONCLUSIONS: In conclusion, this model based on molecular diffusion provides a new insight into the body weight mechanisms.     

Maximum daily ration of juvenile fish fed on living natural zooplankton

Juveniles of five species of cyprinids of body length 15–90 mm as well as juvenile perch, Perca fluviatilis L., were fed on living natural zooplankton over periods of 2 or 3 days. For all species the correlation of the daily ration (% body weight) with body weight showed a maximum curve. The maximum was reached at a body weight (wet weight) of 0.6 g for Leuciscus leuciscus (L.) and 0.1 g for a group consisting of varying numbers of Rutilus rutilus (L.), Abramis brama (L.) and Alburnus alburnus (L.). For L. leuciscus , the maximum was 220% body weight (wet weight), corresponding to 40% on a dry weight basis. For the mixed species group the maximum was about 500% (wet weight) and about 140% on a dry weight basis. The highest daily ration coincided with the occurrence of the spring bloom of zooplankton.     

Relationships between body dimensions and resting and working oxygen consumption in boys aged 11 to 18 years

The relationships between VO2 at rest, VO2max and VO2 during submaximal work on a treadmill with body weight, height and lean body mass assessed by densitometry were analyzed annually in 39 boys aged 11 to 18 years. Interindividual differences in VO2 at rest and VO2max during growth depended in the first place on interindividual differences in lean body mass, to a lesser extent on differences in body weight and least on differences in height. Intersubject differences in VO2 during submaximal work were primarily conditioned by differences in body weight, due to the fact that, at a given running speed, energy output depends on body weight. The differences in submaximal VO2 depended to a lesser extent on differences in lean body mass and least on differences in height. The relationships between VO2 increments and increases in body dimensions were somewhat different in 90 boys between the ages of 11 and 15 years: VO2max increments were determined primarily by changes in body weight and height, changes in lean body mass being of secondary importance. Increases in submaximal VO2 were influenced decisively by increments in body weight, followed by increments in lean body mass and least by increments in height. In the equation y = a.xb expressing the relationship of VO2max to body weight and height, the values of b at the ages of 14 and 15 years were 0.87 and 0.88 in relation to body weight, 2.63 and 2.72 in relation to height. These values are significantly higher than the theoretical values of 0.67 for body weight and 2.00 for height. Similar significant differences from these theoretical values were found for all values between the ages of 11 and 15 years.     

The relationship between body and gonadal weights of the dusky leaf monkey (Presbytis obscura)

Data from 25 male and 44 female free-ranging dusky leaf monkeys, Presbytis obscura,are analyzed. In a male the mean total testicular weight, 5.82 g, represents 0.078% of the mean adult body weight, 7.39 kg. The mean total ovarian weight, 0.52 g, represents 0.008% of the mean female adult body weight, 6.47 kg. A moderate degree of sexual dimorphism thus exists in this species, female body weight representing 88% that of the male. No seasonal variation in the adult body weight or total gonadal weight of either sex occurs. Only in males is there a strong positive correlation between left and right gonadal weight, and no correlation exists between the total gonadal weight and the estimated age of either male or female adults. Among adults, only females evince a significant positive correlation between total gonadal weight and body weight. No marked change in total ovarian weight occurs during the menstrual cycle, pregnancy, or lactation.     

Influence of prenatal malnutrition on later body-weight gain in guinea pigs]

In prenatally underfed guinea pigs the following data were obtained: 1. On the 1st day of life the mean body weight of 18 underfed animals was significantly reduced as compared to that of 18 control animals. This difference was not compensated by postnatal feeding ad libitum but persisted up to the 36th week of life (day of sacrificing). 2. The mean food intake per day estimated over 10 days during the 5th month of life was also significantly diminished in the prenatally underfed animals. 3. A significant positive correlation was found between the body weight at birth and the adult body weight, adult body length and adult body weight/body length, when the parameters of the experimental plus control animals were evaluated together. These findings suggest that in guinea pigs, which are born in a relatively mature stage, the prenatal nutrition can influence body weight, body length and body weight/body length ratio as well as food intake in adulthood.     

Effects of bilateral auricular acupuncture stimulation on body weight in healthy volunteers and mildly obese patients

We investigated the effects of auricular acupuncture stimulation on non-obese healthy volunteers and mildly obese patients. Subjects (n = 55 and 5, respectively) averaged 34.5 years old, and BMI was 24.3 and less than 27.5 kg/m2, respectively. We also studied the effects of single-blind sham treatment in approximately 500 age-, sex-, and BMI-matched subjects. Small (0.15 x 2.0 mm) auricular needles were placed intracutaneously into the bilateral cavum conchae identified by having a resistance of less than 100 kOmega/cm2. In the 2-week pretreatment the period, in which body weight was measured without auricular acupuncture stimulation, 57.1% of the subjects showed a reduction in body weight. This indicates that charting one's own body weight might itself be a useful method of weight control. In the auricular acupuncture treatment period, 35 healthy subjects of 55 (63.6%) showed a decreased body weight, 11 (20%) showed an increased body weight, and 9 (16.4%) showed no change in body weight. The obese patients showed individual variation, but all achieved weight reduction, with a highly significant correlation between body weight and fat volume. The CT/MRI cross-sectional pictures supported these findings. Sham treatment had no statistically significant effect on body weight. These results suggest that success in achieving weight reduction can be partly attributed to the act of charting of one's own weight pattern. Bilateral auricular acupuncture stimulation can help reduce body weight both in mildly obese patients and in healthy non-obese subjects. In conclusion, this is in accord with the bilateral auricular acupuncture stimulation that it may be useful in the treatment of the obesity. We propose a possible mechanism for the weight-reducing effects of bilateral auricular acupuncture stimulation.     

The Influence of Change in Marital Status on Weight Change Over One Year

Marital status is an influence on body weight. Changes in marital status and body weight were examined in the National Survey of Personal Health Practices and Consequences, a telephone survey of 2,436 adults interviewed twice approximately 1 year apart. Two statistical methods for analyzing weight change were compared, and both produced similar results: regression analysis of weight change and regression analysis of weight at follow-up controlling for baseline weight. The findings revealed that women who entered marriage had greater weight change than women who remained married. Analysis of weight gain and weight loss separately showed that women who became married lost less weight than those who remained married. For men, there were no statistically significant relationships between marital change and weight change over a 1-year period. These findings support other literature showing that marital status plays a role in body weight changes. The results suggest gender differences may exist in the rate of body weight change after marriage, with more immediate changes in women than men.     

Investigations on empty body weight gain,on protein,fat and energy deposition as well as on utilization of metabolizable energy for energy deposition at black and white bulls

Six series of individual feeding experiments (altogether 544 animals) with different energy supply and connected with steps slaughteries and whole‐body analyses, constructed carried out and analysed upon the same aspects, were regression analytically interpreted with the aim of quantify the relation of empty body weight to live weight.

The relation of empty body weight to live weight showed a nonlinear dependence on the live weight as well as on the age of animals.

The assessment of the metabolizability of energy of the diet as an additional variable reduced the residual variation considerably. Therefore from the knowledge of live weight or age of the animals, and the metabolizability of energy of the diet the relation of empty body weight to live weight of black and white bulls could be calculated. Moreover the relation of empty body weight gain to live weight gain in dependence on live weight and live weight gain was investigated.     

Critical weight in the development of insect body size

Body size is one of the most important life history characters of organisms, yet little is known of the physiological mechanisms that regulate either body size or variation in body size. Here, we examined one of these mechanisms, the critical weight, which is defined as the minimal mass at which further growth is not necessary for a normal time course to pupation. The critical weight occurred at 55% of peak larval mass in laboratory-reared larvae of the tobacco hornworm Manduca sexta. We examined the effects of genetic and environmental variation in the critical weight on body size. As in many other insects, Manduca larvae reared on poor diets were smaller and those reared at lower temperatures were larger than control animals. We demonstrated that the critical weight was lower on low quality diets but did not change with temperature. There was significant genetic variation for body size, for plasticity of body size, and for critical weight, but not for plasticity of critical weight. Variation in the critical weight accounted for 73% of between-family variance in peak larval size, whereas plasticity of critical weight was not significantly correlated with plasticity of body size. Our results suggest that although critical weight is an important factor in determining body size and enabling the evolution of body size, it may, at the same time, act as a constraint on the evolution of plasticity of body size. Thus, the determinants of body size and the determinants of plasticity of body size do not need to be identical.     

LY79771: a novel compound for weight control

Compound LY79771 given subcutaneously reduced weight or decreased weight gain of genetically obese rats and mice, gold thioglucose obese mice, and obese beagles. The compound had no effect on body weight of lean rats. Food consumption was not decreased. Obese rats showed a transient rise in body temperature after each administration of the drug. The change in body weight was due mainly to a decrease in body fat mass.