Mature size and maturing rate in RoC57BL/6 and RoNMRI lines of mice

Abstract

Summary In mammals, between‐species correlation between mature size and maturing rate is high. The within‐species relationship is not so clear. An experiment with 167 mice of small RoC57BL/6 and large RoNMRI lines was set up, to study the influence of animal mature size on maturing rate. The body mass of animals was measured every 3 days, between the ages 12 and 120 days. Individual ages at half the adulthood and at adulthood were determined on the basis of logistic growth curves. Three linear statistical models based on an allometric equation were used to test between‐line, between‐sex‐line, and between‐family maturing rates. Growth rate and maturing rate are within the species significantly affected by mature size. At mature size, the smaller RoC57BL/6 mice were older than the larger RoNMRI mice. In the model with the significant effects line, sex and family included, the same allometric coefficient was positive. The model which includes an allometric equation within line and sex was no better fitting than the previous model. Not all the estimates of allometric coefficients were within expected ranges, but standard errors were relatively high. Because significant effects are partly of genetic origin and standard errors are high, the selection for higher maturing rate might be possible without changes in mature size. No method for determining degree of maturity during growth has been found so far, therefore the selection would be relatively slow, due to the extension of generation interval. Zusammenfassung Adulte Größe und Wachstumsrate von RoC57BL/6 und RoNMRI Mäusen In Säugern ist die korrelazion zwischen adulter Größe und Wachstumstrate hoch, aber innerartlich ist diese Beziehung nicht so klar. In einem Versuch mit 167 Mäusen der kleinen RoC57BL/6 und der großen RoNMRI Linien wurde der Einfluß adulter Größe auf Wachstumstrate untersucht. Körpermasse wurde zwischen Altern von 12 und 120 Tagen alle 3 Tage erhoben. Alter bei halber und voller adulter große wurde mittels logistischer Wachstumskurven geschätzt. Drei lineare statistische Modelle auf der Basis logistischer kurven wurden verwendet zur Schätzung von Wachstumsraten für Linien, Geschlects‐Linien Gruppen und von Familien. Wachstums und Reifungsraten innerhalb Arten werden signifikant von adulter Größe beeinflußt. Die Mäusen der kleineren Linie waren bei Erreichen des adulten Gewichtes älter als jene der größeren. In Modellen mit den signifikanten Wirkungen von Linien, Geschlecht und Familien war derselbe Allometriekoeffizient positiv, aber im Modell mit Linien‐ und Geschlechtsspezifischen Allometriegliechungen war die Anpassung nicht besser. Nicht alle Schätzwerte der Allometriekoeffizienten waren innerhalb des Erwartdsungbereiches, doch waren die Standardfehler hoch. Da die Einflußfaktoren zum Teil genetischen Ursprungs sind Standardfehler hoch, sollte Selektion auf Wachstumstrate ohne Änderung der adulten Größe möglich sein. Allerdings ist keine Methode zur Schätzung der Reife währen des Wachstums bekannt, sodaß solche Selektion aufgrund verlängerter G...

Evaluation of Growth Patterns and Body Composition in C57Bl/6J Mice Using Dual Energy X-Ray Absorptiometry

“…In addition to the study of skeletal growth and regulation [ 12 , 24 , 25 ], C57BL/6J mice have been widely used as a background strain in other research fields such as the study of adipose tissue metabolism [ 11 , 26 ], diet-induced obesity [ 27 ], and endocrine diseases influencing the metabolism of lipid, carbohydrate, and protein such as metabolic syndrome, type 2 diabetes [ 9 , 28 ], or Prader-Willi syndrome [ 29 ]. It has generally been suggested to use only one sex in these experiments to avoid complications arising from this source because there are differences both in magnitude and in change of body components between young males and females [ 30 – 33 ]. Total animal growth or organ growth had been measured in terms of weight dimension, deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and protein contents of whole body or single organs, NMR metabolomics, serum hormones dosages, and tissue composition [ 21 , 26 , 29 , 31 ] measured by invasive and/or ex vivo destructive methods.…”

Asymptotic weight and maturing rate in mice selected for body conformation

“…For statistical analysis, asymptotic weight (A) and maturing rate for body weight (k) were treated as metric traits. Since in mice sexes almost always show quite different growth patterns (Timon and Eisen, 1969;Eisen, 1976;Koops et al, 1987;Kastelic et al, 1996), males and females were treated separately after demonstrating a nonsignificant genotype x sex interaction effect. Differences in asymptotic weight and maturing rate among genotypes within the selection procedure were assessed by one way analysis of variance (Sokal and Rohlf, 1969).…”

Krškopoljski prašič (Krškopolje Pig)

“…The basic data obtained in this review with some of the most commonly encountered meat and fat quality traits measured in longissimus muscle that could be compared are presented in Table 6. In the few studies reporting meat quality of Krškopolje pigs, pH values measured in longissimus muscle at 45 min and 24 h postmortem were around 6.08 [24,[30][31][32][33][34][35][36][37][38][39][40] and 5.47 [11,[21][22][23][24][30][31][32][33][34][35][36][37][38][39][40], respectively. Relatively low average value of pH 45 in the considered studies could be an indicator of a higher presence of an RYR1 mutation in the Krškopolje pig breed [24,41].…”

“…Control diets differed among studies, to see diet composition address to the corresponding source. (Minolta L value; L* = 48 to 52 [11,[21][22][23][24][30][31][32][33][34][35][36][37][38][39][40]) confirm a bit more intensive colour of meat. In the considered studies, SFA, MUFA and PUFA contents were approximately 36, 48 and 16% for intramuscular fat in longissimus muscle [30,31,[33][34][35][36][37][38][39][40] and approximately 39, 48 and 14% for backfat tissue [30,31,[33][34][35][36][37][38][39][40].…”