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 wer e used, Lohmann Selected Leghorn (LSL) and SLU-1329 (a cross bred of Leghor n x Rhode Island Red-line). Chromium oxide was used as a digesta flow marke r at the ileal level. Feed consumption was recorded during 5 days and excre ta were collected quantitatively during this period. At the end of the tria l the birds were sacrificed for crop and ileal content sampling. Significan t interactions between hybrid and diet were found in ileal crude protein di gestibility (P < 0.05); LSL showed higher digestibility when fed the crumbl ed pellets than when fed the mash diet, whereas the results were the opposi te for SLU-1329. This may indicate a difference in nutrient flow and absorp tion depending on genotype. At the total tract level, no differences of imp ortance in nutrient digestibility between diets could be noted. Nonetheless LSL had drier excreta and higher total tract digestibility of organic matt er (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 cro p ingesta having 0.27 mg/g dry matter, compared with and 0.16 mg/g dry matt er for SLU-1329 (P < 0.05). (C) 1999 Elsevier Science B.V. All rights reser ved.