Digestive tract measurements and histological adaptation in broiler lines divergently selected for digestive efficiency.
Two lines of broilers divergently selected for a high (D+) or a low (D-) AME(n) on a wheat-based diet were studied for morphological and histological characteristics of the digestive tract. A total of 630 birds of both lines were slaughtered after a 23-d feeding period. Digestive tract morphology and intestinal histology were investigated on a total of 24 birds to describe the consequences of divergent selection. Birds of the D+ line had 34% heavier gizzards (P < 0.001) and 22% heavier proventriculi than their D- counterparts. In contrast, intestines were 15 to 40% heavier in D- birds, mainly in the jejunum (P < 0.001) and ileum (P < 0.001). Intestinal segments were also longer (between 3 and 6%) in the D- birds. Intestinal villi were larger and longer in D- birds (P < 0.001), mainly in the jejunum (14 to 16%), and crypts were 10 to 15% deeper for the 3 intestinal segments in D- birds (P < 0.001). Muscle layers of the intestine were 17 to 24% thicker (P < 0.001) and goblet cells were 27 to 34% more numerous in the jejunum and ileum of D- birds (P = 0.027). This new characterization of the 2 lines shows that divergent selection based on AME(n) modified the morphology of the proventriculus and gizzard, suggesting greater activity of this compartment in D+ than in D- birds. Intestinal adaptation revealed by visceral organ weight and length and histological modifications in D- birds can be viewed as an attempt to compensate for the low functionality of the gastric area.
de Verdal
H
H
INRA, UR83 Recherches Avicoles, F-37380, Nouzilly, France.
Mignon-Grasteau
S
S
Jeulin
C
C
Le Bihan-Duval
E
E
Leconte
M
M
Mallet
S
S
Martin
C
C
Narcy
A
A
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D002645:Chickens / Q000033:anatomy & histology* / Q000235:genetics* / Q000502:physiology; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000235:genetics* / Q000502:physiology; D041981:Gastrointestinal Tract / Q000033:anatomy & histology*; D009929:Organ Size / Q000235:genetics; D012641:Selection, Genetic; D014908:Triticum