Heritability of Digestibilities and Divergent Selection for Digestion Ability in Growing Chicks Fed a Wheat Diet

Abstract

The genetic parameters of digestibilities for a wheat-based diet were estimated on 864 broilers. Two divergent lines (D+ and D-) were developed based on AMEn. The Rialto wheat variety was used as it is known to result in low digestibility values. Digestibility of lipids (DL), starch (DS), and proteins (DP) were measured individually using Near Infrared (NIR) analysis of freeze-dried excreta. Body weight, feed consumption (FC), feed conversion ratio (FCR) and residual feed consumption (RES) were recorded to evaluate their correlation with AMEn. The mean AMEn value was 3,093 kcal/kg DM (CV = 9.0%), with a range of 1,001 to 4,022 kcal/kg DM, and was highly heritable (0.36 to 0.38) based on the Restricted Maximum Likelihood method. Genetic correlations with BW were low (-0.10 to -0.15). Selection for AMEn can thus be performed without modifying BW. In contrast, the estimated genetic correlations between AMEn and the other traits were highly negative (-0.53 to -0.60 for FC, -0.77 to -0.80 for RES, and -0.77 to -0.84 for FCR). Finally, digestibilities of feed components were moderately to highly heritable (0.33 to 0.47) and highly correlated with AMEn (0.91 for DL, 0.83 for DS, and 0.86 for DP). Selecting for improved AMEn should thus improve digestibility of proteins, starch, and lipids. The first generation of divergent selection on AMEn confirmed these results, D+ and D- lines showing a 13% difference in AMEn (P < 0.0001) and similar BW.

Comparison of gastrointestinal transit times between chickens from D+ and D− genetic lines selected for divergent digestion efficiency

“…Therefore, feeding coarse particles could result in conflicting effects on digestion efficiencies in growing chickens, depending on the nutrients and origin of feed particles. The genetic origin of birds was also shown to influence the effect of coarse particles, as reported by Rougière et al (2009) in a study using the genetic chicken lines D 1 and D 2 selected for divergent digestion efficiency (Mignon-Grasteau et al, 2004). According to Rougiè re et al (2009), coarse particles resulted in improved digestions of protein and energy in bad digesters (D 2 birds), whereas no effect was observed in good digesters (D 1 birds).…”

“…This selection was conducted from 2002 at the Avian Research Unit (INRA, Nouzilly, France), on the basis of the apparent ME value of a wheat-based diet, corrected to zero nitrogen retention (AMEn), measured at 3 weeks of age (Mignon-Grasteau et al, 2004). The wheat samples of diets used for this genetic selection were all from the Rialto cultivar characterized by a very high viscosity of its water extract and a medium hard value.…”

“…D 1 and D 2 chicken lines were developed because it appeared that the overall variability in digestion efficiencies in growing chickens fed various wheat diets came largely from individual birds, and much less came from wheat samples (Choct et al, 1999;McCracken et al, 2001;Carré et al, 2002 and. Therefore, genetic selection appeared to be an efficient way to improve digestion efficiency in growing chickens fed on wheat diets (Mignon-Grasteau et al, 2004;Carré et al, 2007). Besides such economic interest, D 1 and D 2 lines also represent a unique model for the study of physiological and genetic limiting factors of digestion.…”

Forty research issues for the redesign of animal production systems in the 21st century

“…Only very limited knowledge is available on the determinism of intra-specific variability in fiber digestibility in ruminants and pigs. A pioneer study has shown that the capacity of growing chicks to digest lowquality wheat is partially heritable and could be improved by selection (Mignon-Grasteau et al, 2004). Thus, a research priority is the development of breeding program for improving the digestive capacity of individuals (Issue 1: I1).…”

Opportunities to improve nutrient efficiency in pigs and poultry through breeding

“…Correlations between this and other performance traits, such as body weight (BW) gain and FCR were either low or negligible; suggesting that selection for P bioavailability will not affect adversely the performance (Zhang et al, 2003). The attempts of Carré et al (2008;Mignon-Grasteau et al, 2004;Pé ron et al, 2006) to select for overall digestive efficiency in broiler chickens have been more promising, as they reported relatively high heritabilities (0.33 to 0.47) for energy, lipid, starch and protein digestion efficiencies for 3-week-old broilers fed on a wheat-based diet in birds selected for digestive efficiency (Mignon-Grasteau et al, 2004). Interestingly, these differences had disappeared by 8 weeks of age and were affected greatly by diet type (Pé ron et al, 2006;Carré et al, 2008).…”