scholarly journals FOOD CONSUMPTION, FEED EFFICIENCY, METABOLIC RATE AND UTILIZATION OF GLUCOSE IN LINES OF TRIBOLIUM CASTANEUM SELECTED FOR 21-DAY PUPA WEIGHT

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 393-407 ◽  
Author(s):  
Juan F Medrano ◽  
G A E Gall
Keyword(s):  
Metabolic Rate ◽  
Food Consumption ◽  
Tribolium Castaneum ◽  
Feed Efficiency ◽  
Large Body ◽  
Biological Efficiency ◽  
Growth Stages ◽  
Control Line ◽  
Selected Lines ◽  
Selection For

ABSTRACT Food consumption, feed efficiency, metabolic rate and glucose utilization were studied throughout development in one control (1C) and three selected lines (3, 9, 10) of Tribolium castaneum that had been subjected to long term selection for 21-day pupae weight. Growth rate, body composition, cellular growth and the activity of four dehydrogenase enzymes in the same lines have been reported (Medrano and Gall 1976).—Larva of selected lines consumed 1.2 times as much food as the control and gained an average of 2.9 times as much weight. The rapid growth of the selected lines was associated with a gross feed efficiency 20 to 30% above that for the control line. There was also a small but consistent improvement in the conversion of digested food. Average digestibility was higher for selected lines.—There was little apparent differentiation between the control and selected lines in metabolic rate/individual, but the rate measured on a per-unit weight basis was two- to three-fold greater for the control during the active growth stages. Respiratory quotients (R.Q.) of 1.0, indicative of carbohydrate oxidation, were observed through larval growth in all lines. Pupae at 21 days showed R.Q. values greater than 1.0, which were interpreted as resulting from a phenomenon in insects in which CO2 is released by pupae, in large bursts at irregular intervals. The rate constant of glucose oxidation, measured as the rate of C14 labelled CO2 respired during 2- to 6-hour incubation periods, was two- to three-fold higher in the control. In addition, the control line larvae expired 5% to 17% more of the ingested C14 as CO2. It was apparent that control line individuals maintained a much more active turnover of metabolites but without an effective retention of carbon as body substances. The results are discussed in support of the hypothesis that selection for large body size resulted in improved control mechanisms that influence the biological efficiency of growth in Tribolium.

scholarly journals SELECTION FOR BLOOD PRESSURE LEVELS IN MICE

Genetics ◽  
1974 ◽  
Vol 76 (3) ◽  
pp. 537-549
Author(s):  
Gunther Schlager
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Population Bottleneck ◽  
Control Line ◽  
Selected Lines ◽  
High Line ◽  
Selection For ◽  
Random Control

ABSTRACT Response to two-way selection for systolic blood pressure was immediate and continuous for about eight generations. In the twelfth generation, the High males differed from the Low males by 38 mmHG; the females differed by 39 mmHg. There was little overlap between the two lines and they were statistically significant from each other and from the Random control line. There appeared to be no more additive genetic variance in the eleventh and twelfth generations. Causes for the cessation of response are explored. This is probably due to a combination of natural selection acting to reduce litter sizes in the Low line, a higher incidence of sudden deaths in the High line, and loss of favorable alleles as both selection lines went through a population bottleneck in the ninth generation.—In the eleventh generation, the selected lines were used to produce F1, F2, and backcross generations. A genetic analysis yielded significant additive and dominance components in the inheritance of systolic blood pressure.

Effects of Selection for Mass-Independent Maximal Metabolic Rate on Food Consumption

2020 ◽  
Vol 93 (1) ◽  
pp. 23-36
Author(s):  
Cynthia J. Downs ◽  
Jessi L. Brown ◽  
Bernard W. M. Wone ◽  
Edward R. Donovan ◽  
Jack P. Hayes
Keyword(s):  
Metabolic Rate ◽  
Food Consumption ◽  
Maximal Metabolic Rate ◽  
Selection For

TWO-WAY SELECTION ON PUPAL WEIGHT WITH DIFFERENT DEGREES OF INBREEDING IN TRIBOLIUM CASTANEUM

1974 ◽  
Vol 16 (4) ◽  
pp. 765-775 ◽  
Author(s):  
P. Y. Jui ◽  
G. W. Friars
Keyword(s):  
Tribolium Castaneum ◽  
Linear Response ◽  
Significant Interaction ◽  
Pupal Weight ◽  
Base Population ◽  
Significant Progress ◽  
Selected Lines ◽  
Selection Limit ◽  
Selection For ◽  
Seven Generations

Responses to selection for high and low pupal weight in Tribolium castaneum under four different inbreeding systems and two different relative humidities (40 and 70%) were observed for seven generations. By the seventh generation, the coefficients of inbreeding ranged from 0.79 in the full sib lines to 0.12 in the control lines.Heritability of pupal weight estimated by mid-parent offspring regression from the base population was around 0.30 which is lower than the estimates obtained by Bell (1969). However, realized heritabilities were around 0.50. Significant progress was observed for both upward and downward selection. A linear response in pupal weight was observed for most of the selected lines, suggesting that the selection limit had not been reached.Inbreeding caused a reduction of approximately two offspring per 10% increment in the inbreeding coefficient.Asymmetric responses were noted in conjunction with the significant interaction of the degree of inbreeding and the direction of selection.

Changes in skin and fleece characteristics of Scottish cashmere goats following selection for increased annual production and decreased fibre diameter

2003 ◽  
Vol 76 (3) ◽  
pp. 517-522 ◽  
Author(s):  
M. Merchantt ◽  
D. J. Riach
Keyword(s):  
Genetic Selection ◽  
Fibre Diameter ◽  
Control Line ◽  
Selected Lines ◽  
Financial Return ◽  
Fine Line ◽  
Growing Period ◽  
Cashmere Goats ◽  
Selection For ◽  
Staple Length

AbstractThe aim of this experiment was to determine the mechanisms involved in changes in the production of cashmere as a consequence of genetic selection. Skin follicle parameters and pattern of cashmere growth were compared in two selected lines of Scottish cashmere goats and a randomly bred control line. One line, the fine line, had been selected for low fibre diameter, and this had resulted in lower fibre diameter, but the weight of cashmere produced had also been reduced. Selection for fibre quantity and quality to give maximum financial return (the value line) had increased cashmere weight without a significant increase in cashmere diameter.Skin follicle density and the ratio of secondary to primary follicles (S/P ratio) were measured at 5 months of age in 25 female kids from each line. The density of follicles in the value line was greater (P · 0.05) than that in the fine or control lines (means were 21·8, 19·8 and 20·1 follicles per mm2 respectively, s.e.d. 0.73). S/P ratio increased (P · 0.001) from control to fine to value lines (means were 6.5, 7.7 and 8.4 respectively, s.e.d. = 0.30).The rate of cashmere growth (length), peak cashmere length, the duration of the cashmere growing period and dates of initiation and cessation of growth were measured in the same 25 goats from each line between 2 and 3 years of age. These traits were estimated from the regression of measurements of staple length taken at approximately 6-weekly intervals from the start of the growing period until peak staple length was reached. Measurements were made on the shoulder, mid side and hip. There was no difference in cashmere growth rate between the selection lines (average 0·29 (s.e. 0.006) mm/day). Cashmere growth started earliest in the value line and latest in the fine line but the date of cessation of growth was not different. This affected the duration of the growing period which was 183, 163 and 214 days (s.e.d. 9.6, P · 0.001) for the control, fine and value lines respectively. Peak staple length of cashmere was longest in the value line.Increased weight of cashmere in the value line was brought about through an increase in the number of secondary follicles and by an increase in the length of cashmere due to an increase in the duration of the growing period.

scholarly journals The ecological genetics of growth in Drosophila 4. The influence of larval nutrition on the manifestation of dominance

1961 ◽  
Vol 2 (3) ◽  
pp. 346-360 ◽  
Author(s):  
Forbes W. Robertson
Keyword(s):  
Body Size ◽  
Cell Size ◽  
Large Body ◽  
Ecological Genetics ◽  
Selected Lines ◽  
Pacific Population ◽  
Unselected Population ◽  
Selection For ◽  
Different Strains ◽  
Synthetic Media

(1) Two lines have been selected for small wing cell size from the cage Pacific population. Body size was reduced by about 10% and 15% in the two lines which did not regress when selection was relaxed.(2) The effects of crossing each line to the unselected population has been determined in a number of repeated tests on the live yeast medium and also on various sub-optimal synthetic media.(3) The size of the F1, relative to the size of the parents, is greatly influenced by the composition of the larval diet. The F1 may coincide with the mid-parent value but generally significantly exceeds it and is often the same size as the unselected parent population.(4) In crosses to an unselected population on alternative media the F1 was either the same size as the unselected population or exceeded it.(5) Crosses between the selected lines produced an F1 which exceeded the larger parent but remained well below the level of the unselected population.(6) To test for interaction between genes at different loci, chromosomes from the unselected population were substituted in the genetic background of each of the selected lines to provide an array of genotypes in which one, two or three pairs of major chromosomes had homologues derived from different strains. Leastsquares analysis indicated differences between the lines in the distribution of effects among the chromosomes together with the presence of interaction between chromosomes and this was greater for the substitutions in the line which showed the greater consistency of recessive behaviour in crosses to the unselected population.(7) At the end of the selection experiment two lines were selected for large body size from the F2 of the cross between the two selected lines. Both responded to selection for three to four generations and then fluctuated at a level slightly below that of the unselected population.(8) The physiological changes which involve correlated changes in body and cell size differ from those which result from selection for smaller body size, at least in the early stages of such selection, and are associated with differences in genetic behaviour. The apparently recessive property, which involves extensive non-allelic interaction, is progressively established during the course of selection. Apparently selection for smaller cell size is particularly effective in disturbing the normal homeostasis of growth and is accompanied by relatively greater loss of heterozygosis than is likely with equivalent reduction in size due to selection for smaller body as opposed to cell size.

Maximum cold-induced food consumption in mice selected for high locomotor activity: implications for the evolution of endotherm energy budgets

2001 ◽  
Vol 204 (6) ◽  
pp. 1177-1190 ◽  
Author(s):  
P. Koteja ◽  
J.G. Swallow ◽  
P.A. Carter ◽  
T. Garland
Keyword(s):  
Locomotor Activity ◽  
Food Consumption ◽  
Cold Exposure ◽  
Wheel Running ◽  
Correlated Response ◽  
Selected Lines ◽  
Wheel Running Activity ◽  
Significant Difference ◽  
Energy Assimilation ◽  
Selection For

We studied house mice (Mus domesticus) that had been artificially selected for high activity to test the hypothesis that a high capacity for energy assimilation in cold-exposed endotherms could evolve as a correlated response to selection for increased locomotor activity. After 10 generations of selection for increased voluntary wheel-running, mice from four selected lines ran 75 % more wheel revolutions per day than did mice from four random-bred, control lines. The maximum cold-induced rates of food consumption (C(max); mean 10.6 g day(−1)) and energy assimilation (A(max); mean 141 kJ day(−1)) were not significantly higher in the selected than in the control mice. However, in cold-exposure trials, mice from the selected lines maintained body mass better than did mice from the control lines. C(max) and A(max) were positively correlated with the amount of wheel-running activity measured before cold-exposure and also with the rates of food consumption measured when the mice had access to running wheels. In females at least, the correlation was significant not only among individuals but also among adjusted means of the replicate lines, which suggests the presence of a positive genetic correlation between the traits. Thus, despite the lack of a significant difference between the selected and control lines in maximum rate of food consumption, the remaining results conform to the hypothesis that a selection for increased locomotor activity could be a factor behind the evolution of the ability to sustain activity and maintain energy balance during prolonged cold-exposure, as occurred during the evolution of mammalian and avian endothermy.

CARCASS COMPOSITION OF MICE AFTER LONG-TERM SELECTION FOR LARGE SIX-WEEK BODY WEIGHT OR LONG SIX-WEEK TAIL LENGTH

1985 ◽  
Vol 65 (1) ◽  
pp. 239-242 ◽  
Author(s):  
R. I. McKAY ◽  
A. D. GRAHAM ◽  
R. J. PARKER
Keyword(s):  
Body Weight ◽  
Key Words ◽  
Tail Length ◽  
Fat Deposition ◽  
Carcass Composition ◽  
Control Line ◽  
Selected Lines ◽  
Term Selection ◽  
Selection For

Carcass analysis of mice selected for large 6-wk body weight (BW6) or long 6-wk tail length (TL6) is reported. There was no evidence of excessive fat deposition in the selected lines when compared to a randomly bred control line. Key words: Mice, carcass composition, selection, fat

scholarly journals Atmospheric Hypoxia Limits Selection for Large Body Size in Insects

PLoS ONE ◽  
2009 ◽  
Vol 4 (1) ◽  
pp. e3876 ◽  
Author(s):  
C. Jaco Klok ◽  
Jon F. Harrison
Keyword(s):  
Body Size ◽  
Large Body ◽  
Large Body Size ◽  
Selection For
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