Energy value of potato by-products in ruminant.

A digestibility measurement aiming at determining the energetic values of t he three most important by-products of the potato industry was performed in sheep maintained on metabolic pens under standard conditions. The "mash-pe el", a starch rich by-product resulting from a deep peeling of the tubers w as compared to the "screening" (uncooked fault cuttings) and to the "proteo pulp" (starch potato pulp supplemented with protein). All by-products were characterized by a digestibility of the organic matter higher than 80%. The same was true for the digestibility of the crude energy, except for the "p roteopulp" where the value was slightly lower than 80%. The digestibility o f the crude protein and of the crude fiber showed more important difference s between the by-products. In particular, the crude protein was weakly dige stible in the "screening" (26%) whereas the crude fiber was highly digestib le in the "proteopulp" (80%). The net energetic values of the "mash-peel" a nd of the "screening" were close to 1.10 UFL and 1.05 UFV whereas for the " proteopulp", they were of 0.96 UFL and 0.94 UFV.