Total tract and ileal nutrient digestibility of a diet fed as mash or crumbled pellets to two laying hybrids

Two diets, one fed as mash and the other as crumbled pellets, with the same composition and calculated nutrient content, were studied. Two hybrids were used, Lohmann Selected Leghorn (LSL) and SLU-1329 (a cross bred of Leghorn x Rhode Island Red-line). Chromium oxide was used as a digesta flow marker at the ileal level. Feed consumption was recorded during 5 days and excreta were collected quantitatively during this period. At the end of the trial the birds were sacrificed for crop and ileal content sampling. Significant interactions between hybrid and diet were found in ileal crude protein digestibility (P < 0.05); LSL showed higher digestibility when fed the crumbled pellets than when fed the mash diet, whereas the results were the opposite for SLU-1329. This may indicate a difference in nutrient flow and absorption depending on genotype. At the total tract level, no differences of importance in nutrient digestibility between diets could be noted. Nonetheless LSL had drier excreta and higher total tract digestibility of organic matter (P < 0.05) and crude fat, and also higher metabolisable energy (P < 0.1), than SLU-1329. LSL also had higher concentrations of succinic acid in crop ingesta having 0.27 mg/g dry matter, compared with and 0.16 mg/g dry matter for SLU-1329 (P < 0.05). (C) 1999 Elsevier Science B.V. All rights reserved.