Table 5. Effects of dietary crude protein levels and cysteamine (CS) supplementation on mRNA abundance of IGF-1 (insulin)/Akt/FOXO signaling and their target genes in skeletal muscle of finishing pigs.

Item	Normal protein		Low protein		P value
	Control	Cysteamine	Control	Cysteamine	P	CS	P × CS
IGF-1	1.00±0.04	1.53±0.08	1.04±0.04	1.64±0.07	0.228	<0.001	0.551
IGF-1R	1.00±0.04	1.56±0.04	1.05±0.03	1.50±0.06	0.786	<0.001	0.215
IR	1.03±0.04	0.98±0.04	1.06±0.03	0.99±0.05	0.743	0.159	0.851
IRS-1	1.01±0.05	1.36±0.02	1.06±0.04	1.43±0.05	0.144	<0.001	0.785
Akt1	1.03±0.06	1.62±0.04	1.04±0.03	1.58±0.05	0.756	<0.001	0.577
FOXO1	1.02±0.07	0.92±0.06	0.98±0.04	0.91±0.08	0.637	0.197	0.777
FOXO4	1.02±0.07	0.83±0.04	1.01±0.07	0.85±0.06	0.891	0.007	0.838
MAFbx	1.02±0.05	0.54±0.06	1.05±0.07	0.64±0.03	0.279	<0.001	0.525
MuRF1	1.01±0.04	0.93±0.04	1.04±0.06	0.95±0.06	0.562	0.087	0.934

IGF-1, insulin-like growth factor 1; IGF-1R, IGF-1 receptor; IR, insulin receptor; IRS-1, insulin receptor substrate 1. Akt1, protein kinase B, also named PKB; FOXO, Forkhead Box O; MAFbx, muscle atrophy F-box; MuRF1, muscle Ring finger 1. Values are means ± SEM. Values within a row with different letters differ (P<0.05). All traits in this table were analysed with pen as the experimental unit (n = 5). P, main effect of dietary protein levels; CS, main effect of cysteamine supplementation; P×CS, interaction between main effects of dietary protein levels and cysteamine supplementation.