THYROID ACTIVITY IN LINES OF MICE SELECTED FOR LARGE AND SMALL BODY WEIGHT

1972 ◽  
Vol 14 (3) ◽  
pp. 483-494 ◽  
Author(s):  
R. M. Synenki ◽  
E. J. Eisen ◽  
G. Matrone ◽  
O. W. Robison
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Genetic Correlation ◽  
Small Body ◽  
Thyroid Activity ◽  
Maturation Rate

Thyroid activity was measured at 21, 31 and 42 days of age in lines of mice selected for large (H6) and small (L6) 6-week body weight and an unselected control (C2). Mean %181I uptake/(body weight).75was greatest at 21 days (weaning) and decreased exponentially thereafter with females generally having higher values than males. The L6line had a significantly (P < 0.01) higher %131I uptake/(body weight).75than H6at 31 and 42 days. For %131I uptake, disregarding body size, the H6line was significantly (P < 0.01) higher than C2, but the L6and C2, lines did not differ. Mean %131I turnover/day/(body weight).75showed results similar to %131I uptake per unit metabolic body size. However, when body size was not considered, %131I turnover in the L6line was slightly higher than H6at 31 and 42 days of age. Rate of maturation, as measured by age at opening of eyes and vagina and appearance of external ears, coat hair and nipples, was significantly (P < 0.01) more rapid in the H6line compared to L6. Within lines the correlation between growth rate and maturation rate was positive. These data suggest that there is a small positive genetic correlation between body weight at six weeks of age and thyroid activity in mice.

scholarly journals Assessment of the Growth and Reproductive Performance of Cloned Pietrain Boars

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2053
Author(s):  
Junsong Shi ◽  
Baohua Tan ◽  
Lvhua Luo ◽  
Zicong Li ◽  
Linjun Hong ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Performance ◽  
Reproductive Performance ◽  
Semen Quality ◽  
Small Body ◽  
Economic Benefits ◽  
Large Animal ◽  
Significant Difference ◽  
F1 Progeny

How to maximize the use of the genetic merits of the high-ranking boars (also called superior ones) is a considerable question in the pig breeding industry, considering the money and time spent on selection. Somatic cell nuclear transfer (SCNT) is one of the potential ways to answer the question, which can be applied to produce clones with genetic resources of superior boar for the production of commercial pigs. For practical application, it is essential to investigate whether the clones and their progeny keep behaving better than the “normal boars”, considering that in vitro culture and transfer manipulation would cause a series of harmful effects to the development of clones. In this study, 59,061 cloned embryos were transferred into 250 recipient sows to produce the clones of superior Pietrain boars. The growth performance of 12 clones and 36 non-clones and the semen quality of 19 clones and 28 non-clones were compared. The reproductive performance of 21 clones and 25 non-clones were also tested. Furthermore, we made a comparison in the growth performance between 466 progeny of the clones and 822 progeny of the non-clones. Our results showed that no significant difference in semen quality and reproductive performance was observed between the clones and the non-clones, although the clones grew slower and exhibited smaller body size than the non-clones. The F1 progeny of the clones showed a greater growth rate than the non-clones. Our results demonstrated through the large animal population showed that SCNT manipulation resulted in a low growth rate and small body size, but the clones could normally produce F1 progeny with excellent growth traits to bring more economic benefits. Therefore, SCNT could be effective in enlarging the merit genetics of the superior boars and increasing the economic benefits in pig reproduction and breeding.

Inheritance of geographic variation in body size, and countergradient variation in growth rates, in the southern brown bandicoot Isoodon obesulus.

2000 ◽  
Vol 22 (1) ◽  
pp. 9 ◽  
Author(s):  
ML Hale
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Geographic Variation ◽  
Growth Rates ◽  
Habitat Type ◽  
Adaptive Divergence ◽  
Common Environment ◽  
Countergradient Variation ◽  
Large Animals

The inheritance of geographic variation in body size in the southern brown bandicoot (Isoodon obesulus) was investigated through a common-environment crossbreeding experiment. The geographic variation in body size is related to habitat type, suggesting that it may be adaptive. Adults from two locations in Western Australia, Perth (large animals) and Albany (small animals), were collected and offspring from both hybrid and non-hybrid matings were reared under controlled conditions. All four variables examined (head length, pes length, ear length and body weight) were found to possess a large genetic component, supporting the interpretation that the geographic variation in size is adaptive. The three length variables initially showed additive genetic variation, although the variation in body weight displayed dominance. Genetically controlled differences in growth rate were also detected, with the smaller animals, found in the relatively poorer environment, possessing the faster intrinsic growth rate. Thus, not only does there appear to be adaptive divergence in initial body size, but the countergradient variation in growth rates provides additional evidence for adaptive divergence in this species.

scholarly journals The fertility of mice selected for large or small body size

1960 ◽  
Vol 1 (3) ◽  
pp. 393-407 ◽  
Author(s):  
Ruth E. Fowler ◽  
R. G. Edwards
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Follicle Stimulating Hormone ◽  
Weight Ratio ◽  
Total Body Weight ◽  
Control Line ◽  
Small Body Size ◽  
Natural Mating ◽  
Stimulating Hormone

The fertility of two unrelated strains of mice (strains N and C) which had both been selected for large and small body size has been studied.The fertility of pairs of mice in the large or small lines of strain C was unimpaired by selection. In strain N, some of the pairs in the large and small lines, but not in the control line, were sterile. Sterility in the large line was due to the low libido of the males, and not to female infertility. Sterility in the small line was probably due to hypo-functioning of the anterior pituitary of some females: the oestrous cycle was delayed or absent, some mice failed to ovulate after mating, and a high proportion of those mating had no implanted embryos at 12 days' gestation. Oestrus and ovulation could be induced in mice of the small line of strain N by exogenous gonadotrophins, and the proportion of mice with implanted embryos was considerably increased by progesterone supplements.The number of eggs found after natural mating was considerably higher in large mice than in small mice, and was significantly correlated with body weight in the small line of strain C only. The egg-number/body-weight ratio was higher in the lines of strain C than in those of strain N, though the ratios were similar when carcass fat was subtracted from total body weight.The amount of endogenous follicle-stimulating hormone secreted by the mice of the five lines was estimated by inducing ovulation with various amounts of exogenous gonadotrophins, and comparing the number of eggs found after each dose with the mean number ovulated after natural mating. Estimates of the amount of follicle-stimulating hormone secreted by mice of strain C were higher than those for mice of strain N.Differences in the rates of growth and in the numbers of eggs ovulated after natural mating indicate a higher level of pituitary activity in strain C than in strain N.

scholarly journals Growth Rate and Body Size at Maturity of Florida Black Bears

2019 ◽  
Vol 10 (2) ◽  
pp. 458-467
Author(s):  
Tad M. Bartareau
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Maximum Growth ◽  
Black Bears ◽  
Size At Maturity ◽  
Natural Diet ◽  
Human Food ◽  
Younger Age ◽  
Chest Girth

Abstract Growth rate and body size at maturity are important life-history traits of interest because they represent a potential source of fitness variance within a species and provide information for understanding the nutritional condition, fecundity, and dynamics of populations. My objective here was to examine the growth rate and body size at maturity of Florida black bears Ursus americanus floridanus using body length, chest girth, and body weight measurements fitted to the nonlinear von Bertalanffy, Gompertz, and logistic size-at-age growth functions. The von Bertalanffy model had the largest Akaike weight, indicating the best fit for all measurements of both sexes. Growth models showed that females grew more slowly, with a younger age at maximum growth, faster rate at which maturity was reached, and attained significantly smaller asymptotic body length, chest girth, and weight than males. A more conservative growth strategy by females to invest available energy resources to costs of reproduction, together with intrasexual selection among males for larger body size to enhance intimidating and fighting ability to increase reproductive and survival success, are implicated as determinants of the male-biased direction and degree of sexual size dimorphism. In both sexes, the presence of human food in the diet increased the asymptotic body weight from the estimate for bears consuming a natural diet, but differences were insignificant. Females consuming human food had a slightly younger age at maximum growth and continued growth in body weight for a somewhat longer duration than did conspecifics that consumed a natural diet. In contrast, males that consumed human food had a slightly older age at maximum growth and decreased body weight growth somewhat earlier than did conspecifics consuming a natural diet. Florida black bears exhibited a larger asymptotic body size, faster growth rate, and younger age at maximum growth and maturity when compared with conspecifics in other mainland populations. Recognition of Florida black bear growth rate and adult body size provides wildlife managers a foundation for implementing measurable criteria to assess trends in population health.

scholarly journals Modelling the growth of the brown frog (Rana dybowskii)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4587 ◽  
Author(s):  
Qing Tong ◽  
Xiao-peng Du ◽  
Zong-fu Hu ◽  
Li-yong Cui ◽  
Hong-bin Wang
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Management Strategies ◽  
Growth Period ◽  
The Body ◽  
Order Polynomial ◽  
Polynomial Models ◽  
Brown Frog ◽  
Rana Dybowskii

Well-controlled development leads to uniform body size and a better growth rate; therefore, the ability to determine the growth rate of frogs and their period of sexual maturity is essential for producing healthy, high-quality descendant frogs. To establish a working model that can best predict the growth performance of frogs, the present study examined the growth of one-year-old and two-year-old brown frogs (Rana dybowskii) from metamorphosis to hibernation (18 weeks) and out-hibernation to hibernation (20 weeks) under the same environmental conditions. Brown frog growth was studied and mathematically modelled using various nonlinear, linear, and polynomial functions. The model input values were statistically evaluated using parameters such as the Akaike’s information criterion. The body weight/size ratio (Kwl) and Fulton’s condition factor (K) were used to compare the weight and size of groups of frogs during the growth period. The results showed that the third- and fourth-order polynomial models provided the most consistent predictions of body weight for age 1 and age 2 brown frogs, respectively. Both the Gompertz and third-order polynomial models yielded similarly adequate results for the body size of age 1 brown frogs, while the Janoschek model produced a similarly adequate result for the body size of age 2 brown frogs. The Brody and Janoschek models yielded the highest and lowest estimates of asymptotic weight, respectively, for the body weights of all frogs. TheKwlvalue of all frogs increased from 0.40 to 3.18. TheKvalue of age 1 frogs decreased from 23.81 to 9.45 in the first four weeks. TheKvalue of age 2 frogs remained close to 10. Graphically, a sigmoidal trend was observed for body weight and body size with increasing age. The results of this study will be useful not only for amphibian research but also for frog farming management strategies and decisions.

scholarly journals The efficiency of food utilization, digestibility of foodstuffs and energy expenditure of mice selected for large or small body size

1962 ◽  
Vol 3 (1) ◽  
pp. 51-68 ◽  
Author(s):  
Ruth E. Fowler
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Energy Expenditure ◽  
Small Body ◽  
Energetic Efficiency ◽  
Food Utilization ◽  
Control Line ◽  
Small Body Size ◽  
Gross Efficiency ◽  
Body Activity

The efficiency of food utilization, the digestibility of foodstuffs, energy metabolism, and body activity have been studied in three lines of mice, one selected for large, another for small body size, and a third, control, line.The gross efficiency of food utilization was highest in the large line, intermediate in the control line and lowest in the small line between 21 and approximately 35 days of age. During this period, gross efficiency declined in the large and control lines with increasing size and decreasing growth-rate, presumably due to an increase in maintenance costs in comparison with the weight gained. In the small line, the efficiency of food utilization increased up to 35 days of age but declined thereafter. The energetic efficiency (measured in Calories) was higher in the large than in the small line up to 4 weeks of age, i.e. when the growth-rate was high, and after 6 weeks of age, when fat was being deposited at an increased rate.The increased efficiency of large mice was not entirely associated with a greater proportion of the ingested food being absorbed from the gut. Large mice absorbed a greater proportion of protein, though the difference was not sufficient to account for the large weight difference between the large and small lines.The energy expenditure of mice of the large line was greater than that of the small line at all ages and similar for the same body weights. The reduced growth-rate of small mice was not due to abnormally high or low energy costs. There was no evidence that body activity determined or restricted the rate of growth in either line.Mice selected for small size were phenotypically unlike pituitary dwarf mice, although the low nitrogen retention during the growing-period indicated a deficiency of some growth stimulus.

scholarly journals Energy balance in rats given chronic hormone treatment

1989 ◽  
Vol 61 (3) ◽  
pp. 445-452 ◽  
Author(s):  
Christopher J. H. Woodward ◽  
Peter W. Emery
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Energy Balance ◽  
Hormone Treatment ◽  
High Energy ◽  
Fat Free Mass ◽  
Sprague Dawley ◽  
The Difference ◽  
And Control

1. Sprague–Dawley rats were given corticosterone for 4 to 14 d either by subcutaneous injection (50 mg/kg body-weight per d) or as a higher dose in the diet (1 g/kg diet). Energy balance was calculated using the comparative carcass technique.2. Corticosterone significantly suppressed growth rate by at least 50% (P < 0·001 in all experiments). The reduction in growth was more marked in males than in females.3. Hormone treatment significantly reduced metabolizable intake (kJ/d) in males but not in females. Expressed relative to either metabolic body size (kg body-weight0·75) or fat-free mass, metabolizable intake tended to be increased in the treated groups.4. Energy expenditure, calculated as the difference between metabolizable intake and gain and expressed as kJ/d, did not differ between treated and control rats. Relative to either metabolic body size or fat-free mass, expenditure was consistently increased in treated rats. This change was statistically significant in five of the eight comparisons.5. The corticosterone-treated rat is characterized by high energy intake and expenditure relative to its body size and growth rate. Alterations in the relative sizes of different lean tissues may contribute to these changes.

scholarly journals The size and endocrine activity of the pituitary in mice selected for large or small body-size

1962 ◽  
Vol 3 (3) ◽  
pp. 428-443 ◽  
Author(s):  
R. G. Edwards
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Primary Response ◽  
Endocrine Activity ◽  
Body Weights ◽  
Mouse Pituitary ◽  
Highly Correlated ◽  
Thyroid Secretion

Mice of two strains, N and C, were used in studies on body-size, pituitary size, and endocrine potency of the pituitary. Strain N had been selected for large (NL) and small (NS) body-size; strain C had also been selected for large body-size (CL) but had been crossed to an outbred strain segregating pituitary dwarfism.Pituitary weights and body-weights were highly correlated, the regression lines being common in NL and NS mice. Female pituitaries were considerably heavier than male pituitaries in CL mice. In relation to body-weight, CL pituitaries were consistently heavier than those of NL or NS mice.No differences were detected in the unit potency of gonadotrophins in the pituitaries of NL and NS mice as estimated by the uterine response of immature outbred mice to subcutaneous injections of pituitary tissue. The uptake of 131I into the thyroid was comparable in NL and NS mice per unit of body-weight, and the thyroid secretion rate was also similar using animals of the same body-weight. Immature mice of both lines responded by increased growth to injections of growth hormone or fresh mouse pituitary, though the response was greater in NS than in NL mice.The primary response to selection has probably been in the size of the pituitary rather than in its unit potency. The interrelationships between body-size, body components, organ size and endocrine levels are discussed.

The growth and carcass composition of strains of mice selected for large and small body size

1958 ◽  
Vol 51 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Ruth E. Fowler
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Carcass Composition ◽  
Small Body Size ◽  
Body Protein ◽  
Percentage Composition ◽  
Growing Period ◽  
Constant Rate ◽  
Rates Of Growth

The growth and carcass composition of two strains of mice (N- and C-strain), which had both been selected for large and small body size by Falconer, have been studied.Differences in body weight between mice of the N-strain and their controls were apparent at birth and were fully maintained up to 30 weeks of age. The patterns of growth were similar in all three lines, although the large line grew at a faster rate than the small line, the controls being intermediate. Differences in absolute and relative rates of growth between the three lines reach a maximum from 21 to 35 days of age and declined thereafter.Growth in the large line of the N-strain from 14 to 40 days of age was largely due to an increase in body protein and water; after this age, increase in weight was caused mainly by fat deposition. In the small line of this strain, protein, water and fat were deposited at a more constant rate during the whole growing period. Differences in rates of growth may account for the differences in the percentage composition found between mice of the large and small lines of the N-strain at the same age.

scholarly journals CORRELATED RESPONSES IN MALE REPRODUCTIVE TRAITS IN MICE SELECTED FOR LITTER SIZE AND BODY WEIGHT

Genetics ◽  
1981 ◽  
Vol 99 (3-4) ◽  
pp. 513-524
Author(s):  
E J Eisen ◽  
B H Johnson
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Litter Size ◽  
Small Body ◽  
Large Body ◽  
Reproductive Traits ◽  
Correlated Response ◽  
Testis Weight ◽  
Correlated Responses ◽  
Large Litter

ABSTRACT Correlated responses in male reproductive traits were determined at 4, 6 and 8 weeks of age in lines of mice selected for large litter size (L+), large 6-week body weight (W+), large litter size and small body weight (L+W-) and small litter size and large body weight (L-W+), and in an unselected control (K). Concentration of serum testosterone and weights of testes, seminal vesicles, epididymides and adrenal glands increased with age. Line differences in testosterone concentration were not detected. L+ and W+ males exhibited positive correlated responses in testes, epididymides and seminal vesicle weights. Testis weight adjusted for body weight was significantly larger for L+ than controls and approached significance for Wf . Realized genetic correlation betestis weight and litter size was 0.60± 0.04, and the realized partial genetic correlation holding body weight constant was 0.42. Therefore, pleiotropic loci, acting viathe hypothalamic-pituitary axis, affect testis weight and litter size independently of body weight. Additionally, genes influencing overall growth have a pleiotropic effect on testis weight and litter size in mice; the realized genetic correlations of body weight with testis weight and with litter size were 0.60 ± 0.03 and 0.52 ± 0.10. Testis weight increased in both L+W- and L-W+ males. The positive correlated response in L+W- may have resulted from changes in frequency of genes controlling reproductive processes; whereas, in L-W+ it could have been the result of changes in the frequency of genes associated with body weight.

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