Age at first reproduction and growth rate are independent of basal metabolic rate in mammals

Empirical studies have shown that in teleosts there is a significant correlation between the life history parameters, age at first reproduction, natural mortality, and growth rate. In this paper 1 hypothesize that these correlations are the result of evolutionary adjustments due to the trade-off between reproduction, growth, and survival. A simple and reasonable assumption is that the costs of reproduction are sufficient to cause the ltmt function to decrease. A simple expression relating the age at first reproduction is derived from this assumption. This formula accounts for a statistically significant portion (60.6%) of the variation in age at first reproduction in 30 stocks of fish. To extend the model to predict the distribution of life history parameters across all teleosts, an explicit cost function is incorporated. The model is analyzed with respect to two fitness measures, the expected lifetime fecundity and malthusian parameter, r. In the first case it is shown that the optimal age at maturity, T, depends only on the natural mortality rate (M) and the growth rate (k). In the second case, T is a function of k and the logarithm of a parameter, In C; the latter is a product of egg and larval survival, maximum body length (Lx), and the proportionality coefficient of the fecundity/length function. Difficulties of measuring egg and larval survival make the testing of the latter case difficult for particular species. However, this method provides a simple formula for the computation of r; this is shown generally to be approximately zero, thereby adding strength to the assumptions of the first analysis. The distribution patterns of T on k and M on k are predicted and compared with the observed pattern. In general, the predictions are validated: however, certain combinations of k and ln C are shown to occur very infrequently. The prediction of such "empty" regions of the parameter space remains a challenge for future development of life history theory.

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Basal metabolic rate in lambs and young sheep

Australian Journal of Agricultural Research ◽

10.1071/ar9740957 ◽

1974 ◽

Vol 25 (6) ◽

pp. 957 ◽

Cited By ~ 55

Author(s):

NMcC Graham ◽

TW Searle ◽

DA Griffiths

Keyword(s):

Growth Rate ◽

Body Weight ◽

Metabolic Rate ◽

Basal Metabolic Rate ◽

Body Weight Gain ◽

Adult Cattle ◽

Adult Sheep ◽

Free Weight ◽

Wide Range ◽

Average Adult

Basal metabolic rate (BMR) was determined in 56 crossbred sheep, up to 10 observations being made on each animal between 1 week of age and 2¼ years. The level of feeding was varied amongst the sheep so that there was a wide range in growth rate at each age. BMR was estimated as heat production under standard conditions of fasting. Trends during fasting were studied in four sheep at ages 3 weeks, 2 months and 9 months. The effects on BMR of body weight (or fat-free weight), age, prior growth rate and prior nutrition were examined statistically by estimating the parameters of a series of model equations by a least squares iterative method. Analysis of lamb and sheep data separately and combined showed that all these variates contributed significantly to BMR. Of the variance of BMR, 89% was accounted for in a body weight term, kgx, in which the value of x was not significantly different from ¾ if one or more of the other variates were in the model; x was unity when fat-free weight was used instead of body weight. If body weight was used alone, x was smaller for both lambs and weaners, being c. 0.60; with fat-free weight the values for lambs and weaners were 0.71 and 0.96 respectively. Age, growth rate and level of feeding were of approximately equal importance, together accounting for a further 6% of the total variance. BMR declined by c. 8% per annum and was affected to the extent of 2.8 kJ per gram body weight gain and 46 kJ per MJ digestible energy intake before fasting (all values per 24 hr). Thus an increase in growth rate in a lamb from zero to maximal (0.3 kg/day) caused BMR to increase by 50%, and an increase of food intake by 1 kg/day in an average adult sheep caused BMR to increase by 10%. For any given set of these variates, BMR was 23% higher in milk-fed lambs than in weaned sheep. An equation was derived for sheep in general; the residual standard deviation was c. 300 kJ/24 hr, or 7-8% of BMR in an average adult sheep. Some evidence was cited to show that this equation may be used to predict BMR in growing and adult cattle by multiplying the whole expression by 1.3.

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Basal metabolic rate is positively correlated with parental investment in laboratory mice

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.2576 ◽

2013 ◽

Vol 280 (1753) ◽

pp. 20122576 ◽

Cited By ~ 30

Author(s):

Julita Sadowska ◽

Andrzej K. Gębczyński ◽

Marek Konarzewski

Keyword(s):

Growth Rate ◽

Metabolic Rate ◽

Basal Metabolic Rate ◽

Parental Investment ◽

Foster Mother ◽

Term Selection ◽

Genetically Determined ◽

Investment Capacity ◽

Assimilation Capacity ◽

Line Type

The assimilation capacity (AC) hypothesis for the evolution of endothermy predicts that the maternal basal metabolic rate (BMR) should be positively correlated with the capacity for parental investment. In this study, we provide a unique test of the AC model based on mice from a long-term selection experiment designed to produce divergent levels of BMR. By constructing experimental families with cross-fostered litters, we were able to control for the effect of the mother as well as the type of pup based on the selected lines. We found that mothers with genetically determined high levels of BMR were characterized by higher parental investment capacity, measured as the offspring growth rate. We also found higher food consumption and heavier visceral organs in the females with high BMR. These findings suggested that the high-BMR females have higher energy acquisition abilities. When the effect of the line type of a foster mother was controlled, the pup line type significantly affected the growth rate only in the first week of life, with young from the high-BMR line type growing more rapidly. Our results support the predictions of the AC model.

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THE EFFECT OF HYPOTHYROIDISM ON THE GUINEA-PIG

Journal of Endocrinology ◽

10.1677/joe.0.0080229 ◽

1952 ◽

Vol 8 (3) ◽

pp. 229-233 ◽

Cited By ~ 2

Author(s):

ELIZABETH M. HUMPHREYS

Keyword(s):

Growth Rate ◽

Guinea Pig ◽

Metabolic Rate ◽

Normal Control ◽

Basal Metabolic Rate ◽

Guinea Pigs

Thiouracil was administered to young guinea-pigs from a month before birth until either the time of birth or until they were 8 weeks old. The basal metabolic rate of these animals was depressed, their thyroids were hyperplastic and took up tracer doses of 131I more slowly than normal. Nevertheless the growth rate of such animals did not differ significantly from that of normal control guinea pigs.

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A stage-explicit expression of the von Bertalanffy growth model for understanding age at first reproduction of Great Lakes fishes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-008 ◽

2002 ◽

Vol 59 (2) ◽

pp. 250-261 ◽

Cited By ~ 28

Author(s):

Ji X He ◽

Donald J Stewart

Keyword(s):

Growth Rate ◽

Great Lakes ◽

Body Length ◽

Growth Parameters ◽

Growth Potential ◽

Growth Trajectories ◽

Annual Growth Rate ◽

Von Bertalanffy ◽

Age At First Reproduction ◽

First Reproduction

An initial annual growth rate of body length and its regular decrease with increasing age has general linkages with age at first reproduction (tR). We clarify their combinations and develop predictive functions. We use a complete FordWalford plot with yearling size (L1) on the y axis and show a slope transition between the relative yearling growth rate (ρy) and the FordWalford slope (ρ). The three stage-specific variables define a complete body-length trajectory over ages, including all von Bertalanffy growth parameters and the FordWalford intercept (Lint). The difference between asymptotic length (Linf) and yearling length is growth potential after the first annulus. Yearling growth is a transition period, so growth potential can be adjusted as ρLinf or Linf Lint. Changes in the three life-stage variables have contrasting effects on growth potential and von Bertalanffy growth parameters, so they have contrasting relations with tR. For most invertebrate-eating fishes in the Laurentian Great Lakes, dominant changes in growth trajectories were reflected in ρ, so tR was predicted by the von Bertalanffy growth coefficient, K. For walleye (Stizostedion vitreum) populations around the Great Lakes, dominant changes in growth trajectories were from yearling size or yearling growth, so tR was predicted using Lint. Our results have clear implications for understanding fish population dynamics.

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Larger guts and faster growth in mice selected for high basal metabolic rate

Biology Letters ◽

10.1098/rsbl.2021.0244 ◽

2021 ◽

Vol 17 (10) ◽

Author(s):

Julita Sadowska ◽

Andrzej K. Gębczyński ◽

Marek Konarzewski

Keyword(s):

Growth Rate ◽

Metabolic Rate ◽

Basal Metabolic Rate ◽

High Growth ◽

Postnatal Growth ◽

High Energy ◽

High Growth Rate ◽

Functional Link ◽

Size Growth ◽

Future Outcomes

Postnatal growth in birds and mammals is the time of highest vulnerability and relatively high energy demands and therefore shapes the organisms' future outcomes. Several different factors might impose limitations on growth in juveniles, one of them being the efficiency of the digestive process and size of the gastrointestinal tract. We tested the gut size–growth rate relationship using a unique experimental model—mice from a selection experiment designed to produce two lines with divergent levels of basal metabolic rate (BMR): the high BMR (H-BMR) and low BMR (L-BMR) line types. These lines differ with respect to not only BMR, but also correlated traits—internal organ size and food intake. Applying a cross-fostering design and a thermoregulatory burden imposed by shaving the mothers, we demonstrated that the mass of intestine strongly affected the growth rate, with the H-BMR pups having larger intestines and growing faster, and with reduced growth rate of pups of both lines nursed by shaved L-BMR mothers. Our study also provides a functional link between high growth rate of neonates and high BMR of adults, partly reflecting metabolic costs of maintenance of their guts.

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Development of new predictive equations for basal metabolic rate in Iranian healthy adults: negligible effect of sex

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000669 ◽

2020 ◽

pp. 1-10

Author(s):

Bahareh Nikooyeh ◽

Nastaran Shariatzadeh ◽

Ali Kalayi ◽

Maliheh Zahedirad ◽

Tirang R. Neyestani

Keyword(s):

Metabolic Rate ◽

Thyroid Function ◽

Basal Metabolic Rate ◽

Age Groups ◽

Thyroid Function Tests ◽

Anthropometric Measures ◽

Predictive Equations ◽

Normal Thyroid Function ◽

Asian People ◽

Predictive Formulas

Abstract. Some studies have reported inaccuracy of predicting basal metabolic rate (BMR) by using common equations for Asian people. Thus, this study was undertaken to develop new predictive equations for the Iranian community and also to compare their accuracy with the commonly used formulas. Anthropometric measures and thyroid function were evaluated for 267 healthy subjects (18–60 y). Indirect calorimetry (InCal) was performed only for those participants with normal thyroid function tests (n = 252). Comparison of predicted RMR (both kcal/d and kcal.kg.wt−1.d−1) using current predictive formulas and measured RMR revealed that Harris-Benedict and FAO/WHO/UNU significantly over-estimated and Mifflin-St. Jeor significantly under-estimated RMR as compared to InCal measurements. In stepwise regression analysis for developing new equations, the highest r2 (=0.89) was from a model comprising sex, height and weight. However, further analyses revealed that unlike the subjects under 30 y, the association between age and the measured RMR in subjects 30 y and plus was negative (r = −0.241, p = 0.001). As a result, two separate equations were developed for these two age groups. Over 80 percent of variations were covered by the new equations. In conclusion, there were statistical significant under- and over-estimation of RMR using common predictive equations in our subjects. Using the new equations, the accuracy of the calculated RMR increased remarkably.

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COMBINATION OF POTASSIUM PERCHLORATE AND PROPYLTHIOURACIL IN THE TREATMENT OF THYROTOXICOSIS

Acta Endocrinologica ◽

10.1530/acta.0.0570565 ◽

1968 ◽

Vol 57 (4) ◽

pp. 565-577 ◽

Cited By ~ 4

Author(s):

K. E. Røkke ◽

J. H. Vogt

Keyword(s):

Drug Therapy ◽

Side Effects ◽

Metabolic Rate ◽

Total Cholesterol ◽

Basal Metabolic Rate ◽

Combined Therapy ◽

Combined Treatment ◽

Control Measures ◽

Potassium Perchlorate ◽

Plasma Total Cholesterol

ABSTRACT A report is given on 95 thyrotoxic patients treated with a combination of 400 mg propylthiouracil and 400 mg of potassium perchlorate. Perchlorate was stopped when a marked remission of symptoms was obtained, on an average after less than 7 weeks. Euthyroidism was found on an average after 7.2 weeks. The basal metabolic rate, PBI, plasma total cholesterol and weight showed a fairly rapid normalization. Thirteen of the 95 patients were given radio-iodine therapy shortly before drug therapy was started. The remaining 82 cases were grouped together with the 23 cases previously reported. Of the total of 105 cases, 96 became euthyroid on combined therapy. For the frequency of side-effects, the thirteen cases mentioned above were included, giving a total of 118 cases. Eight cases showed an increase in goitre size and 15 cases had other side-effects, of which three were granulocytopenia due to propylthiouracil. The possibility of a higher frequency of mainly minor side-effects on combined therapy has to be balanced against the seemingly rapid and reliable therapeutic effect. Combined treatment, perhaps with even smaller doses than reported here, can be recommended in selected cases of thyrotoxicosis where a shortening of the thyrotoxic state seems of importance, or possibly where difficulties due to iodine exposure may be anticipated, provided adequate control measures are taken.

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