Effect of Tannin-Binding Agents (Polyethylene Glycol and Polyvinylpyrrolidone) Supplementation on In Vitro Gas Production Kinetics of Some Grape Yield Byproducts

Maghsoud Besharati,Akbar Taghizadeh

doi:10.5402/2011/780540

Abstract

The effects of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) on in vitro gas production characteristics, organic matter digestibility (OMD), and metabolizable energy (ME) contents of some grape yield byproducts were investigated. The gas production was recorded after 2, 4, 6, 8, 12, 16, 24, 36, and 48 h of incubation. The gas production profiles in triplicate fitted with equation Y = A (1 – e−ct). The data was analyzed using completely randomized design. Total phenol (TP) and total tannin (TT) contents were highest for raisin waste (RW). The TP content (g/kg DM) ranged from 30.1 in grape pomace (GP) to 96.3 in RW, which also had the higher TT (72.1 g/kg DM). The potential gas production (a + b) of DGB, GP, and RW were 239.43, 263.49, and 208.22 mL/g DM, respectively. In the absence of PEG and PVP, rate constant of gas production (c) for GP was highest among the feedstuffs (0.1073 mL/h), but in presence of PEG or PVP, RW had highest fraction (c) among the feedstuffs. Addition of PEG and PVP inactivated effects of tannins and increased gas production, ME, NE1, OMD, and VFA in grape yield byproducts. Addition of PEG and PVP could overcome adverse effects of tannins on nutrient availability as indicated by gas production parameters.

Highlights

A major constraint to increasing livestock productivity in developing countries is the scarcity and fluctuating quantity and quality of the year-round supply of conventional feeds
Total phenols and total tannin contents were highest for raisin waste
Gas production (c) for grape pomace (GP) was highest among the feedstuffs (0.1073 mL/h), but in presence of polyethylene glycol (PEG) or PVP, raisin waste (RW) had highest fraction (c) among the feedstuffs

Summary

Introduction

A major constraint to increasing livestock productivity in developing countries is the scarcity and fluctuating quantity and quality of the year-round supply of conventional feeds. These countries experience serious shortages in animal feeds of the conventional type. There is a need to identify and introduce new and lesser known food and feed crops. An important class of nonconventional feeds is byproduct feedstuffs which are obtained during harvesting or processing of a commodity in which human food or fibre is derived. The amount of byproduct feedstuffs generally increases as the human population increases and economies grow [1]

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Discussion

Conclusion