Effect of dietary supplementation of crude glycerol or tallow on intestinal transit time and utilization of energy and nutrients in diets fed to broiler chickens

Influence of the inclusion of co-products of the soy oil industry in poultry diets on nutrient digestibility, growth performance, and production

“…Similar results were observed with increases in the level of GLYC of the diet. This effect has been reported by others with inclusion levels of glycerol up to 10% (Kim et al 2013;Zavarize et al 2014). …”

“…These authors reported that supplemental fat delays the intestinal transit time of the digesta, allowing a better contact between the components of the digesta and the endogenous enzymes present in the GIT, which in turn could improve nutrient utilization. However, Kim et al (2013) were not able to detect any benefit of glycerol supplementation on the intestinal transit time of the digesta in 31-d old broilers. Therefore, other mechanisms might be involved.…”

“…Diets were formulated to have similar calculated AME n concentration according to Fundación Española Desarrollo Nutrición Animal (2010), assuming in all cases a metabolicity of 96% for the GE of the glycerol contained in the GLYC. Kim et al (2013) reported also that the TTAR of DM and GE, but not of N, increased when 5% glycerol was included in the diet of 31 d-old broilers. Similarly, Swiatkiewicz and Koreleski (2009) did not detect any significant effect on N retention when up to 6% GLYC was included in the diet of laying hens, consistent with the results of the current experiment.…”

“…In broilers, Mandalawi et al (2014) did not detect any effect on TTAR of N and GE when up to 100 g GLYC/kg was included in the diet. Similarly, Kim et al (2013) reported no differences in TTAR of N and EE in broilers fed diets that contained 50 g GLYC/kg but GE retention increased with GLYC supplementation. Also, Peña et al (2014) reported that the inclusion of Groesbeck et al (2008) reported that TTAR of GE and N were not affected when up to 60 g GLYC/kg was included in the diet, in agreement with the results reported herein.…”

“…The maximum level of inclusion of GLYC in laying hen diets for optimal production, has been estimated within the range of 50 to 100 g/kg (Lammers et al, 2008;Swiatkiewicz and Koreleski, 2009;Németh et al, 2013). Also, the inclusion of GLYC in broiler diets increased dry matter (DM) and gross energy (GE) retention (Kim et al, 2013;Mandalawi et al, 2014). In spite of the commercial interest for using GLYC as an energy source in the diet, little information is available on the effects of GLYC on total tract apparent retention (TTAR) of dietary components and egg quality in laying hens.…”