ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 68 Number 1
Use of ash of cocoa pod husk as a source of alkali for upgrading agricultural residues with or without hydrogen peroxide
Ash obtained from cocoa pod husk was sprayed on wheat straw at 40, 80 or 120 g kg-1 straw with 30, 45 or 60 g 100 g-1 moisture level, and subsequently ensiled for l, 2 or 3 weeks. Potential degradability or organic matter loss (OML) from samples incubated in nylon bags for various periods in the rumen of the sheep and assessed by the mathematical model p =a+ b (1 –e-ct). (where a+ b is the potential degradability and c the rate constant) increased from 566 for the untreated to 626 g OML kg-1 OM for 80 g ash kg-1 straw treatment. Subsequent increase in ash concentration did not further improve OML. Increasing ensiling period from 1 to 3 weeks increased degradability from 584 to 638 g kg-1 (P < 0.01). Increasing moisture level resulted in increased potential degradation from 588 to 620 g OML kg-1 OM. The rate constant (c) tended to decrease with increasing ensiling period (P < 0.01), but it was not affected by other treatments. In all cases, treatment with cocoa pod ash was accompanied by reduction in lignin, hemicellulose and nitrogen. In another experiment, maize stover, brewer's dried grains (BDG), cowpea straw and cowpea husk were soaked in solutions containing 10 or 50 g H2O2 I-1 with or without ash as the alkaline source. There was no effect of H2O2 alone, but alkaline H2O2 did increase OML in maize stover and BDG from 698 to 781 and 723 to 856 g OML kg-1, respectively, for the 50 g I-1 alkaline H2O2 treatment. On the other hand, the leguminous residues were not affected by all treatments. Carbohydrate and total phenolics composition showed higher loss of non-cellulosic sugar residues and solubilization of phenolic materials in the maize stover and BDG than the leguminous ones. In one experiment, it was shown that loss of solubilized sugar from the different residues was considerably greater when they were soaked in alkaline H2O2 solutions than when the solutions were sprayed directly onto the material.
Keywords: Cocoa-pod ash; Agricultural residues; Ensilage; Ruminant feed