Evaluation of nutritive value and in vitro methane production of feedstuffs from agricultural and food industry by-products

Abstract

The aim of this research was to evaluate the nutrient degradability, in vitro methane (CH4) production of several agricultural and food industry by-products in relation to their chemical composition. Twenty-one samples of 7 feedstuffs from agricultural and food industry by-products consisted of corn straw, potato straw, rice straw, cocoa pod, sago waste, rice bran, soybean curd residue were evaluated by an in vitro gas production and nutrient degradability. The feedstuffs varied greatly in their crude protein (CP), neutral detergent fiber (NDF) and non-fiber carbohydrate (NFC) contents. Crude protein ranged from 1.5 to 21.8%, NDF from 31.6 to 71.1% and NFC from 1.5 to 50.8%. Among the seven feedstuffs, soybean curd residue had the highest CP content, on the other hand it had the lowest NDF content. Dry matter (DM) and organic matter (OM) degradability were highest (P<0.01) in soybean curd residue among the feedstuffs. The CH4 production was significantly higher (P<0.01) in rice straw, cocoa pod and corn straw as compared to sago waste. There was a strong positive correlation (r = 0.60; P<0.01) between NDF concentration and CH4 production. However, the total gas productions was negatively correlated (r = -0.75; P<0.01) with NDF content. The CH4 production of feedstuff is influenced by NDF content.