Litter size manipulation in laboratory mice: an example of how proteomic analysis can uncover new mechanisms underlying the cost of reproduction

Table 1 ANOVAs for Global parameters in litters and reproductive adult females

Variable	Covariates	Repeated factor	Random factor	Control litters	Enlarged litters	Reduced litters		P-value
Variable	P-value	P-value	P-value	(n = 4)	(n = 4)	(n = 4)		P-value
	[Estimates]	[Estimates]	[Estimates]	[Estimates]	[Estimates]	[Estimates]
(a) Litter parameters
Initial litter size (pup number)				8.3 ± 0.8	6.8 ± 0.5	7.3 ± 0.9	F_2,11 = 1.61	0.253
Initial litter size (pup number)				[0]	[-2.0 ± 1.2]	[-0.5 ± 1.2]	F_2,11 = 1.61	0.253
Final litter size (pup number)				7.0 ± 0.9	9.3 ± 0.6	4.5 ± 0.7	F_2,11 = 5.97	0.022
Final litter size (pup number)				[0]	[1.0 ± 1.1]	[-2.8 ± 1.1]	F_2,11 = 5.97	0.022
Final Litter mass (g)	Final litter size			49.9 ± 4.0	45.4 ± 4.7	59.0 ± 5.3	F_2,11 = 1.35	0.313
Final Litter mass (g)	P = 0.001			[0]	[-4.5 ± 5.8]	[9.1 ± 7.2]	F_2,11 = 1.35	0.313
	[8.3 ± 1.6]
(b) Adult female parameters
Initial body mass (g)	Initial litter mass	Stage	Individual	27.4 ± 2.6	28.5 ± 2.6	31.7 ± 2.6	F_2,8.2 = 4.00	0.061
Initial body mass (g)				26.5 ± 2.6	27.7 ± 2.6	30.8 ± 2.6
Final body mass (g)	P = 0.040	P = 0.225		27.0 ± 2.5	28.1 ± 2.6	31.2 ± 2.5
Mean female body mass (g)	[0.2 ± 0.1]	[3.5 ± 2.8]	[4.1 ± 3.6]	[0]	[1.40 ± 1.8]	[4.9 ± 1.8]
Final oxidative stress (mg H2O2/mL)	Antioxidant capacity			10.5 ± 0.7	12.4 ± 0.7	10.0 ± 0.7	F_2,11 = 5.57	0,030
Final oxidative stress (mg H2O2/mL)	P = 0.002			[0]	[1.9 ± 0.8]	[-0.8 ± 0.8]	F_2,11 = 5.57	0,030
	[0.1 ± 0.1]

Results of ANOVAs for global parameters in litters (a) and reproductive adult females (b) subjected to litter size manipulation (Control, FEL and FRL groups). “Initial” refers to pre-reproduction (i.e. 3 weeks before pairing) while “Final” refers to offspring emancipation (Day 21) characteristics. Analysis of variation in adult female body mass over time and treatment was done using a Mixed Model (see Statistic description for details).

ISSN: 1742-9994