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

Abstract

D 1 (high digestion efficiency) and D 2 (low digestion efficiency) genetic chicken lines selected for divergent digestion efficiency were compared in this experiment. Gizzard functions were tested in terms of digesta mean retention time and reactions to high dilution of a corn diet with 15% coarse sunflower hulls. The corn standard (S) and high fibre (F) experimental diets were given from 9 days of age to chickens from both lines. Besides the measurements of growth efficiencies (9 to 20 days), digestibilities (20 to 23 days) and gut anatomy (0, 9, 29, 42 and 63 days), two digestive transit studies were performed at 9 and 29 days of age. For the transit studies, the S and F diets were labelled with 0.5% TiO 2 and 1% Cr-mordanted sunflower hulls. These diets were fed ad libitum during 3 days, and then the birds were euthanized. The digestive contents were analysed for the determination of marker concentrations and mean retention times (MRTs) in digestive compartments (crop 1 oesophagus, proventriculus 1 gizzard, duodenum 1 jejunum, ileum, rectum 1 cloaca and caeca) were determined. D 1 birds were confirmed as better digesters than D 2 birds during the growth period, in association with larger gizzard and pancreas, and lighter small intestine in D 1 than in D 2 birds. The MRT in the proventriculus-gizzard system, higher in D 1 than in D 2 birds, was a major factor associated with differences between D 1 and D 2 birds regarding digestion efficiencies and gut anatomy. Diet dilution with fibres reduced differences in digestion efficiencies and proventriculus-gizzard MRT between lines. Differences in gut anatomy between lines tended to disappear after 8 weeks of age. In conclusion, this study showed that MRT in the proventriculus-gizzard system was a major factor associated with genotype differences between the D 1 and D 2 genetic chicken lines selected for divergent digestion efficiency, with longer MRT found in D 1 than in D 2 birds.

Growth performance and carcass yield of broiler chickens fed commercial finisher and cassava copra meal-based diets

“…Structural feed components have been reported to be retained in the gizzard for a longer time (Rougière & Carré 2010;Svihus 2011;Meremikwu et al 2013). The high fibre content of the test diet which must have resulted in increased digesta retention time in the gastro-intestinal tract may be a reason for the lower feed intake observed in the present experiment.…”

Breeding for efficiency in the broiler chicken: A review

“…This suggests that the birds which have been specifically selected for high digestive efficiency are genetically predisposed to growing a large gizzard. The gizzard size may also play a vital role in improving digestive efficiencies by increasing the mean digesta retention time, described by some as the greatest influencing factor in the improvement of digestive efficiency (Pym 1985;Maisonnier et al 2001;Pishnamazi et al 2005;González-Alvarado et al 2008;Rougière and Carré 2010). Therefore, should digestive efficiency have increased, the gizzard might be expected to be larger in modern broilers relative to body mass.…”

“…Contrasting correlations in relative organ sizes have been discovered between lines selected for commercial objectives and high digestive efficiency (Carré et al 2005;Péron et al 2006;Rougière and Carré 2010;de Verdal et al 2010). For instance, Mussini (2012) showed that the gizzard is significantly smaller, and the pancreas similar, in modern commercial breeds when compared to old-type breeds fed on the same diet.…”

“…The morphometries of the internal structures, in particular the organs that comprise the digestive system, are significantly different between high digestive efficiency lines and birds bred for high commercial performance (Carré et al 2005;Péron et al 2006;Rougière and Carré 2010). Selecting for high digestive efficiency may conflict with performance traits and this probably goes part way to explaining why the genetic change witnessed in broilers does not appear to have delivered their full digestive efficiency potential, at least not to the extent it could have had digestive efficiency been the only trait of interest in breeding programs.…”

Influence of nutritional strategies on growth performance and digestive tract traits of brown egg laying pullets and subsequent effects on egg production

“…The inclusion of fibrous ingredients in poultry diets reduces feed intake (FI) (Kondra et al, 1974;Sklan et al, 2003) and nutrient digestibility (Rougière and Carré, 2010) and might affect the incidence of enteric disorders in poultry (Montagne et al, 2003;Shakouri et al, 2006;Mateos et al, 2012). Recent research conducted with young broilers, however, have shown that the inclusion of moderate amounts of insoluble fiber sources, such as oat hulls (OH) and sunflower hulls (SFH), in the diet stimulates the development and physiology of the gastrointestinal tract (GIT) Svihus, 2011;Sacranie et al, 2012) and might improve broiler performance González-Alvarado et al, 2010).…”