Dietary fiber content affects growth, body composition, and feed intake and their associations with a major growth locus in growing male chickens of an advanced intercross population

Abstract

In this study, we examined the effect of different dietary fiber concentrations on growth, body composition, and feed efficiency of growing male chickens with different genetic background. We tested whether the single nucleotide polymorphisms (SNP) in a previously identified growth locus on chromosome 4 (GGA4) between 69.3 and 77.9 Mb was associated with the traits of biologic and commercial importance in interaction with the diet. The study was conducted with growing male chickens of generation 12 of an advanced intercross population descending from the initial cross between inbred New Hampshire (high-growth) and White Leghorn (low-growth) lines. We performed a 2-way interaction analysis between the dietary fiber content and SNP genotypes. At wk 4, the growing male chickens were randomly divided into 2 diet treatments, which were housed and fed individually with either a low- (LFD, n = 38) or a high-fiber diet (HFD, n = 41) containing 0.8 and 5% lignocellulose with a crude fiber content of 60%, respectively. Body weights were recorded weekly. Body composition was examined at wk 13. Feed intake and excreta were analyzed at wk 6 and 13. The effect of dietary fiber content on body weight gain and feed intake was age-dependent. The feed conversion ratio was not altered. Feeding HFD resulted in 10% greater body weight gain (P = 0.047) and greater feed intake (P = 0.014) than LFD at wk 6. At wk 13, the visceral adipose tissue mass was 38% lower (P = 0.008) and the gizzard mass was 14% greater (P = 0.012). The reduction of total fat content in adipose tissue (P = 0.039) in the HFD was associated with reduced intramuscular fat content in drumsticks-thighs (4.2 vs. 5.1%, P = 0.004). The SNP genotypes at the GGA4 locus interacted with dietary fiber content and influenced body weight gain (P = 0.042), visceral adipose tissue mass (P ≤ 0.029), and feed intake (P ≤ 0.050). The New Hampshire alleles of SNPs on GGA4 led to increased body weight gain and feed intake (P ≤ 0.050), and tended to reduced fat deposition under HFD. Our data indicate that the addition of lignocellulose to the diet would improve productivity and carcass quality through reduced adipose tissue mass without changes in feed efficiency. Furthermore, our findings provide evidence for interaction of the target GGA4 region with dietary fiber usage affecting growth, fat deposition, and feed intake. The particular GGA4 locus may contain a single or several genes associated with growth, body composition, and feed intake.