Effect of polyethylene glycol and polyvinylpyrrolidone on in vitro gas production of raisin waste
Advances in Animal Biosciences
Introduction In the Middle East, animals suffer from under feeding and malnutrition in winter due to the shortage of locally produced feeds which are not sufficient to cover the nutritional requirements of the animals (Besharati and Taghizadeh, 2009). The annual amount of agricultural by-products produced in Iran is large. The production of grape exceeds 2.87 million tonnes/year, with a high proportion of the yield being used for production of dried grape products. In this process, large
... ocess, large amounts of raisin waste are produced. Raisin waste contains of pieces of raisin plus grape cluster stems. There is little information available on the nutritive value of raisin waste. However, inclusion of grape by-product in the diet reduced digestibilities of the diet (Baumgartel et al., 2007) . Yinrong Lu and Yeap Foo (1999) reported that grape pomace tannins have adverse effects on nutrient utilisation, and are toxic at high intake levels (Reed, 1995) due to their ability to bind proteins, minerals and carbohydrates (McSweeney et al., 2001) . Tannins are the most widely occurring antinutritional factor in non-conventional feeds. Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) have a high affinity for tannins. Addition of PEG results in the formation of PEG-tannin complexes which inactivates tannins. The aim of this study was to determine the effect of PEG and PVP on in vitro gas production kinetics of raisin waste.