Digeribilità in vivo di due mangimi composti ricchi in fibra in razioni per cavalli.

CommercialIy mixed feeds for light horse feeding are being used ' more and more and, in recent times, a particular role has been played by mixed feeds characterized by high fibre percentages together with pre-biotic or pro-biotic supplements. Consequently, more data about these new feeds is required. The apparent digestibility of two commercialIy mixed feed was determined by means of four in vivo digestibility trials (hay n.l; hay n. l + mixed feed n.l; hay n.2; hay n.2 + mixed feed n.2) each performed on 4 or 5 saddle horses weighting about 550 and 535 kg respectively over a 6 day faeces total colIection period with a previous 14 day adaptation periodo The diets were based on first cut meadow hay and two mixed feed at a feeding level close to maintenance. The two mixed feed were rich respectively in by-product of citrus fruits industry (citrus pulp) and in by-product of apple fruits industry (apple pectin pulp). The forage to concentrate ratios were 100:0 and 50:50, respectively, in the four trials. The apparent digestibility of the dry matter, organic matter, gross energy, crude protein, NDF, ADF and crude fibre were measured by the ingesta/excreta procedure for alI the rations and the hays. The apparent digestibility of the two concentrates were calculated from the above data. The results showed that the addition of the first mixed feed to the hay improves lightly the digestibility ofthe ration with the exception offibre fractions (crude fibre, NDF, ADF) that was lower; in the case ofthe second by-product the comparison with the digestibility values obtained with the hay only showed lower values for dry matter, organic matter, energy and NDF and negative values for crude fibre and ADF. These results could mainly be ascribed to a negative effect of these by-products on the microtlora activity in the large intestine, mainly of the cellulosolytic one. Nevertheless, it could be supposed the addition of preservati ve substances to the fibrous part of the raw materials that could negatively intluence the fermentation activity.