Growth in perspective

Reeds, Peter J.; Fiorotto, Marta L.

doi:10.1079/pns19900048

Cited by 12 publications

(5 citation statements)

References 31 publications

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“…This result, recently confirmed by C hudy et al (1997) with these mouse lines, is well documented for mice (E isen 1976; R ucklidge 1982; M alik 1984; B ishop et al 1984; F an et al 1996) and rats (W ebster 1993). It is not known, whether this change reflects an active up‐regulation of fat storage or merely an increased availability of organic nutrients above that needed to support protein deposition (R eeds and F iorotto 1990). In the present study the second possibility appears unlikely as the energy concentration of the diet used was about 10% lower than NRC recommendations (NRC 1995), whereas the dietary protein concentration exceeded the recommendations of NRC for growing mice by about 20% and was high enough to favour protein deposition.…”

Section: Discussionmentioning

confidence: 99%

Protein metabolism in mice selected for high carcass protein content or high body weight

Schadereit

Klein

Souffrant

et al. 1997

Animal Physiology Nutrition

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Summary Protein turnover, efficiency of growth and body composition were investigated in N balance experiments with growing male mice (26‐36 days of age) which were long‐time selected for high carcass protein amount (DU‐6P) or for high body weight (DU‐6) and in the unselected randomly bred control (DU‐Ks). In total 12 mice per line were housed singly in metabolic cages and had free access to a commercial stock diet (crude protein 267 g, gross energy 19 MJ/kg dry matter). N balance, whole body protein synthesis (PS, end‐product method, single dose of 15N‐labelled amino‐acid mixture), fractional myofibrillar muscle breakdown rate (FBR, 3‐methylhistidine method) and N distribution in the body were measured. Additionally, the maintenance nitrogen requirement (MNR) and the maximum possible rate of N accretion (MNA) of the different lines was estimated after feeding semi‐synthetic diets with increasing protein levels. Body weight of both selection lines was about twice that of the control mice at the same age. The DU‐6P mice synthesized and deposited more protein and less fat per unit metabolic BW, than the DU‐6 mice did. However, scaled to the corresponding body protein pools, the rates of protein synthesis were not significantly different between both selection lines in contrast to the deposition rate. Selection for high body weight resulted in higher body fat content, higher muscle FBR and a lower proportion of carcass N compared to DU‐6P mice. The protein synthesis (13‐14 g protein/kg BW0.75 per day) and MNR values (290‐305 mg N/kg BW0.75 per day) of the selected mice were higher than those of control mice (11 g protein and 265 mg N/kg BW0.75, respectively) and may be due to selection‐linked enlargments of visceral organs. The MNA of DU‐6P and DU‐6 mice amounted to 6 and 5 g protein/kg BW0.75, respectively, and the MNA of the controls was between these values. Compared to DU‐6, the higher protein accretion rate of DU‐6P mice seems to be due more to a lower muscle protein breakdown rate than an increased protein synthesis rate. Zusammenfassung Proteinumsatz von Mäusen, die auf hohen Körperproteingehalt oder auf hohes Körpergewicht selektiert wurden An je 12 wachsenden männlichen Mäusen, die über 80 Generationen am 42. Lebenstag entweder auf hohen Proteingehalt im Schlachtkörper (DU‐6P) oder auf hohe Lebendmasse (DU‐6) selektiert worden waren, wurden Proteinstoffwechsel, Wachstumseffizienz und Körperzusammensetzung im Vergleich zur unselektierten Kontrollinie (DU‐Ks) untersucht. Die Tiere wurden einzeln in Stoffwechselkäfigen bei freiem Zugang zu Wasser und Altromin‐Zuchtfutter (Rohprotein 267 g/kg TS, Bruttoenergie 19 MJ/kg TS) gehalten. Neben der N‐Bilanz wurden Gesamtkörper‐Proteinsynthese (PS, Endproduktmethode, einmalige Gabe einer 15N‐Aminosäurenmischung, Auswertung mittels Kompart‐mentmodell), fraktionelle Muskelprotein‐Abbaurate (FBR, 3‐Methylhistidin‐Methode), Verteilung des Körperstickstoffs, N‐Erhaltungsbedarf (MNR, regressiv nach Fütterung semi‐synthetischer Rationen mit steigenden Proteinniveaus) sowie m...

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Section: Discussionmentioning

confidence: 99%

Protein metabolism in mice selected for high carcass protein content or high body weight

Schadereit

Klein

Souffrant

et al. 1997

Animal Physiology Nutrition

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“…Throughout life, the mass of many organs alters in response to changes in the physical or metabolic work that each is called upon to perform (REEDS and FIOROTTO, 1990). The skeleton, being the scaffold that bears the weight of soft tissues, must adapt structurally to respond to the mechanic demand posed by the biomass it has to support.…”

Section: Discussionmentioning

confidence: 99%

Effect of disruptive selection for body conformation on age variations of femoral morphometrie traits, in mice

et al. 1999

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SummaryThe effect of disruptive selection for body conformation on body weight and length, tail length, and femur weight and length at different stages of development (21, 42, 63, and 120 days of age) was analysed in four mouse lines of the CBi stock selected for (CBi+, CBi-) and against (CBi/L, CBi/C) the phenotypic correlation between body weight and tail length, and die unselected control line CBi. As expected, body weight and tail length distributed according to the selection criteria; rrunk length (whole body length minus tail length) behaved as body we lg ht at all ages. CBi/L had the highest femoral length (p<0.01), and CBi/C attained the highest femoral weight (p<0.01). CBi+ and CBi-, harmonically large or small, differed between them and from the control line in both variables (p<0.001). These findings further corroborate the proposal that bone mass is markedly affected by the skeleton function as support of soft tissues. The allometric analysis ofthe regression of femur weight on femur length suggests that, in this model, a) the demand posed by the selective pressure forced each genotype to find a unique Solution, b) this response is sex-dependent, and c) genetic determination ofthe parameters involved in this allometric relationship is, at least, partially independent. Key words: disruptive selection, body conformation, femur weight, femur length, mice Zusammenfassung Titel der Arbeit: Der Einfluß der disruptiven Selektion nach Körperkonfoi mation auf die Altersvariation der morphometrischen Merkmale des Femurs bei der Maus Der Einfluß einer disruptiven Selektion nach Körperkonformation auf die Körpermasse und -länge, Schwanzlänge und Masse bzw. Länge des Femurs im Alter von 21, 42, 63 und 120 Tagen wurde in vier Populationen des CBi-Stammes analysiert. Neben der unselektierten Kontrollpopulation erfolgte die Selektion in den Linien (CBi+, CBi-) auf die phänotypische Korrelation zwischen Körpermasse und Schwanzlänge und in den Linien (CBi/L; CBi/C) gegen diese Korrelation. Wie erwartet, veränderten sich die Körpermasse und Schwanzlänge entsprechend der Selektionskriterien. CBi/L hatte die höchste Femurlänge (P<0,01) und CBi/C das höchste Gewicht des Femurs. Die allometrische Analyse der Regression des Femurgewichtes zur -länge zeigte in diesem Modell: a) der Selektionsdruck führte in jeder Linie zu einer anderen Lösung, b) diese Veränderungen sind geschlechtsabhängig und c) die genetische Determination der Regressionsparameter ist teilsweise voneinander unabhängig.

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“…Growth can be studied from at least three interrelated perspectives: dimensional, compositional and functional (Reeds and Fiorotto, 1990). From the dimensional viewpoint, the term growth refers to an increase in some measure of size (height, length, weight) with age.…”

Section: Introductionmentioning

confidence: 99%

Asymptotic weight and maturing rate in mice selected for body conformation

2000

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Growth patterns of four lines of mice selected for body conformation were analyzed with the logistic function, in order to provide baseline information about the relationship between asymptotic weight and maturing rate of body weight. Two lines were divergently selected favoring the phenotypic correlation between body weight and tail length (agonistic selection: CBi+, high body weight and long tail; CBi-, low body weight and short tail), whereas the other two lines were generated by a disruptive selection performed against the correlation between the aforementioned traits (antagonistic selection: CBi/C, high body weight and short tail; CBi/L, low body weight and long tail). The logistic parameters A (asymptotic weight) and k (maturing rate) behaved in CBi/C and CBi- mice and in CBi+ females as expected in terms of the negative genetic relationship between mature size and earliness of maturing. An altered growth pattern was found in CBi/L mice and in CBi+ males, because in the former genotype, selected for low body weight, the time taken to mature increased, whereas in the latter, selected for high body weight, there was a non-significant increase in the same trait. In accordance with the selective criterion, different sources of genetic variation for body weight could be exploited: one inversely associated with earliness of maturing (agonistic selection), and the other independent of maturing rate (antagonistic selection), showing that genetic variation of A is partly independent of k.
Padrões de crescimento de 4 linhagens de camundongos selecionados para a conformação do corpo foram analisadas com a função logística, de modo a se obterem informações basais a respeito da relação entre o peso assintótico e a taxa de maturação do peso corporal. Duas linhagens foram selecionadas divergentemente, favorecendo a correlação fenotípica entre o peso corporal e o comprimento da cauda (seleção agonística: CBi+, peso corporal elevado e cauda longa; CBi-, peso corporal reduzido e cauda curta), enquanto que as outras duas linhagens foram geradas por uma seleção disruptiva feita contra a correlação entre os caracteres acima citados (seleção antagonística: CBi/C, peso corporal elevado e cauda curta; CBi/L, peso corporal reduzido e cauda longa). Os parâmetros logísticos A (peso assintótico) e k (taxa de maturação) comportaram-se em camundongos CBi/C e CBi- e em fêmeas CBi+ conforme esperado, em termos da relação genética negativa entre o tamanho maduro e a precocidade de maturação. Um padrão alterado de crescimento foi encontrado em camundongos CBi/L e em machos CBi+, porque no primeiro genótipo, selecionado para reduzido peso corporal, o tempo decorrido para a maturação aumentou, enquanto que no último, selecionado para elevado peso corporal, houve um aumento não significante no mesmo caráter. De acordo com o critério de seleção, fontes diferentes de variação genética para o peso corporal puderam ser exploradas: uma inversamente associada com precocidade de maturação (seleção agonística) e a outra independente da taxa de matu...

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Growth in perspective

Cited by 12 publications

References 31 publications

Protein metabolism in mice selected for high carcass protein content or high body weight

Protein metabolism in mice selected for high carcass protein content or high body weight

Effect of disruptive selection for body conformation on age variations of femoral morphometrie traits, in mice

Asymptotic weight and maturing rate in mice selected for body conformation

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