Macro-biophysical properties of candidate novel feedstuffs for poultry feeding.

Information on the proximate composition and sometimes the toxicology of novel feedstuffs has been used routinely in determining the suitability of feedstuffs in poultry feeding, especially during animal feeding trials. Limited information however exists on the biophysical characteristics of such novel feedstuffs. The Bulk Density (BD), Water-holding Capacity (WHC) and Specific Gravity (SG) of three novel feedstuffs {Leaf Meal (LEM), Rumen Digesta (RD) and Poultry Dung (PD)}, were evaluated. Available published and unpublished results on the proximate compositions of the materials were related to the physical characteristics results. LEM had significantly (p > 0.05) lower BD and SG than RD and PD while RD recorded the highest WHC value although the value was similar (p > 0.05) to that of LEM. Particle Size (PS) effects showed that BD of RD and PD were lower at the > or = 1.00 mm PS than at the unmodified and < 1.00 mm PS, indicating that materials of similar Crude Fiber (CF) could be manipulated to yield different BD with possible ultimate effects on the performance of birds. The WHC of LEM at < 1.00 mm PS level was seven times higher than that of unmodified and =1.00 mm PS while RD value at the same < 1.00 mm PS level was 2 and 4 times higher than those recorded at the unmodified and > or = 1.00 mm PS levels, respectively. This is evidence that grinding increased the surface area of the LEM, thus improving the ability of its Non-starch Polysaccharides (NSP) to bind water. Information on the feed physical characteristics could be used together with proximate and toxicological information to determine the nutritional and intake potentials of a novel feedstuff even before a feeding trial.