Azevêdo et al., 2011. Rev. Bras. Zootec., 40 (5): 1052-1060

The objective of this study was to evaluate the effects of inclusion of by-product of fresh fruit (pineapple, guava, papaya, mango and passion fruit) used in the diet for bovines partly replacing corn silage on intake and total nutrient digestibility, on the production of microbial protein and the nitrogen balance and on prediction of digestible fractions and total digestible nutrients (TDN) of these by-products. All animals received corn silage and the urea/ammonium sulfate (9:1) mixture so diets would remain isonitrogenous. The intakes of dry matter (DM) (kg/day), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and TDN, and the digestibility of CP, non-fibrous carbohydrates (NFC) and ether extract (EE) were affected by the source of the by-product. There was an effect for the level of inclusion of products in the digestibility of CP and EE. The by-products of papaya, mango and pineapple showed energy values of 23.1, 18.0 and 7.1% respectively, higher than corn silage. The source of the by-product influenced urinary excretion of derived from total purine, purine absorbed and production of microbial protein, in addition to the intake (g/day), the excretion in feces and urine (g/day) of nitrogen compounds and nitrogen balance (g/day). The level of inclusion of the by-product in the diet affect the urinary excretion of derived from total purine, purine absorbed and microbial protein production. The by-products of pineapple, papaya and mango have energy value higher than corn silage and they can partly replace energy concentrates in diets for ruminants. The by-product of passion fruit has the potential to partly replace roughage in the diets of ruminants. The by-product of guava has use limitations in diets of ruminants.