Effects of ensiling cereal grains (barley, wheat, triticale and rye) on total and pre-caecal digestibility of proximate nutrients and amino acids in pigs

Inclemency of weather frequently causes critical water contents in cereal grains above 15%. Ensiling in pre-mature condition may be an alternative to other techniques of preservation. Aim of this study was to compare apparent total tract digestibility (D-t; barley, wheat, triticale, rye) of proximate nutrients and pre-caecal digestibility (D-pc; barley, wheat) of amino acids (AA), respectively, from cereal grains in ensiled and almost dry condition. Moistly harvested cereal grains (67-73% dry matter) were milled through a 4-mm sieve and ensiled with lactic acid bacteria (LAB, 3 x 10(5) colony forming units/g Lactobacillus plantarum DSMZ 8862 and 8866). To investigate D-t, two trials were conducted with six Mini-Lewe pigs and four German Landrace pigs, respectively. D-pc of AA was determined using four German Landrace pigs with ileo-rectal anastomosis. D-t of proximate nutrients did not differ between cereal grains and their silages, except for ether extract, which was more digestible in ensiled than dry wheat, triticale and rye (p < 0.05). Lysine content was lower in ensiled than dry barley and wheat. In barley, ensiling was accompanied by reduced D-pc of lysine and histidine (p < 0.05). In wheat, ensiling increased D-pc of lysine, methionine, threonine and leucin (p < 0.05). Ensiling of pre-mature cereal grains with LAB can serve as a reasonable storage alternative. However, as limited data are yet available, further research is required to understand completely the impact of ensiling on nutritional value as indicated, for example, by the lysine content and the D-pc of certain AA.