Divergent selection for residual feed intake influences whole blood transcriptomic profile in growing pigs
Résumé
With the aim to improve livestock production efficiency, there
is a need to gain insights into the molecular mechanisms underlying
feed efficiency. There is increasing evidence that whole
blood may provide valuable insight into whole-body energy
homeostasis. The current study was undertaken to determine
whether pig blood transcriptome was affected by genetic selection
for feed efficiency and (or) by nutrition. Large White castrated
male pigs from 2 lines divergently selected for residual
feed intake (RFI) were fed diets with the same ME level and the
same protein content, but either rich in cereals (LF) or in crude
fiber and lipids (HF) during 10 wk in the growing period (n =
12 by diet and by line). At the same slaughter age (132 d), pigs
selected for low RFI had an improved G:F and were leaner than
pigs selected for high RFI. Irrespective of selection line, pigs
fed the LF diet were heavier and fatter at slaughter than pigs fed
the HF diet. Analysis of the blood transcriptome using a porcine
microarray (Agilent, GPL16524, 8 ´ 60K) reveals larger
differences between RFI lines than between diets (2154 vs. 92
probes differentially expressed, DE, P < 0.01). An interaction (P
< 0.01) between line and diet was also detected for 106 probes
corresponding to 57 unique genes. Among the 2154 probes
DE according to the line, 1216 exhibited a ratio of expression
above 1.2 or below 0.8. This corresponds to 260 unique overexpressed
genes and 310 unique down-expressed genes in low
RFI pigs compared with high RFI pigs. Genes over-expressed in
the low RFI pigs compared with high RFI pigs were associated
to the immune response (29 unique genes, cytokine binding,
chemokine binding, and receptor activity), protein catabolism
(24 unique genes, protein ubiquitination, proteolysis), and cell
signal (12 unique genes, regulation of signal transduction). Conversely,
genes underexpressed in low RFI pigs compared with
high RFI pigs were involved in the immune response (64 unique
genes; inflammatory response, regulation of immune system
process), nucleotide transport (49 unique genes), response to
stimulus (25 unique genes), protein transport (22 unique genes),
cell adhesion (21 unique genes), carbohydrate metabolism (19
unique genes), and cell organization (15 unique genes). These
findings suggest differences in the immune status between pigs divergently selected for RFI. Altogether, this study demonstrates
the usefulness of the blood transcriptome investigation to
identify molecular differences between genotypes.
Domaines
Sciences du Vivant [q-bio]
Origine : Fichiers produits par l'(les) auteur(s)