Effects of wheat quality on digestion differ between the D+ and D- chicken lines selected for divergent digestion capacity.
The aim of the experiment was to study the effects of 2 wheat cultivars (Baltimor and Scipion) with different hardness values (75 and 5, respectively) on 2 divergent lines (D+ and D-) of broiler chickens selected on the basis of their digestion ability assessed by AME(n). Wheat was incorporated at 54.6% in diets. The other main ingredients were soybean meal (35.3%) and rapeseed oil (5.5%). Diets were given as pellets from 7 to 26 d. The experimental design was a 2 x 2 factorial design testing 2 wheat cultivars (soft or hard) on 2 selected lines of broiler chickens (high AME(n) or low AME(n)). From 7 to 16 d, D+ line showed lower (P < 0.0001) feed intake and feed:gain ratio than the D- line. At 3 wk of age, the D+ chickens resulted in increased digestibility values (P < 0.01) and 9% increased AME(n) value (P < 0.0001) compared with D-. Wheat cultivar effects on feed efficiency and AME(n) differed between lines. In the D+ line, their values were about 6% higher (P < 0.05) with soft than with hard wheat, whereas they did not differ in the D- line. However, wheat cultivar effect on starch digestibility did not differ between lines; soft instead of hard wheat resulted in about 6% improvement (P < 0.0001) in both lines. In the D- line, soft instead of hard wheat tended to reduce lipid and protein digestibilities, which explained why the starch digestibility improvement due to soft wheat was not converted into a significant AME(n) improvement in D birds. Study of digestive organ size revealed that increased proventriculus and gizzard weight (P < 0.05) could be one of the causes for the better digestion capacity of the D+ line. The pancreas was bigger (P < 0.01) in D- than in D+ birds, which probably came from an adaptation to a digestive disorder in D- birds.
Péron
A
A
Station de Recherches Avicoles, Institut National de la Recherche Agronomique, 37380 Nouzilly, France. peron@tours.inra.fr
Gomez
J
J
Mignon-Grasteau
S
S
Sellier
N
N
Besnard
J
J
Derouet
M
M
Juin
H
H
Carré
B
B
D000821:Animal Feed / Q000592:standards*; D000818:Animals; D002645:Chickens / Q000145:classification* / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D004063:Digestion / Q000502:physiology*; D004064:Digestive System / Q000033:anatomy & histology; D005838:Genotype; D008297:Male; D009929:Organ Size; D014908:Triticum