UTILIZATION OF COCOA-POD PERICARP FRACTIONS IN BROILER CHICK DIETS

As a means of shedding some light on the limitations of cocoa-pod husk (CPH) as a feed ingredient for livestock, particularly the non-ruminants, the proximate, non-starch polysaccharides plus lignin, and mineral components of the husk and its layers (epicarp, mesocarp and endocarp) were determined. Each material was then incorporated at 0%, 5% and 10% levels in isoprotein broiler starter diets. Each diet was fed to duplicate groups of 10 1-day-old broiler chicks for 4 weeks. The husk had high proportions of total ash (> 9%), crude fibre (> 20%), cell-wall contents (hemicellulose, 11%; cellulose, 35%; lignin, 15%; pectin, 6%) and mineral elements (K, 3.18%; Ca, 0.32%; P, 0.15%). The epicarp was the most lignified layer and had the highest amounts of total ash, Ca, K, P and all other inorganic elements assayed. The mesocarp had the bulk (approx. 50%) crude fibre and cellulose contents. The endocarp, although most balanced in proximate components, contained about 60% of the pectic substances. In the feeding trial, both levels (5% and 10%) of the epicarp depressed (P<0.05) weight gain and feed efficiency. Apparent dry matter utilization was reduced on all 10% test material inclusions. Gizzard weight tended to increase on the mesocarp diets while the intestine was longer (P<0.05) on the 10% epicarp diet. Results in this study show that the epicarp (outer pericarp) is the most limiting portion of the CPH. The results also indicate that it is not fibre quantity per se but the components (principally lignin and pectin, probably acting jointly in an adverse manner) that are inhibitory to the utilization of CPH in broiler diets.