FUNGAL-DEGRADED MAIZE BY-PRODUCTS AS FEED FOR WEST AFRICAN DWARF RAM

Abstract

Maize by-products are potential feed resources for ruminants if properly harnessed. Their uses are however limited by high fibre content and low digestibility which can be enhanced by fungal degradation. Information on the use of fungal-degradation of maize by-products as feed for ram is scanty. The nutritive value of biodegraded maize by-products in West African Dwarf (WAD) ram was therefore assessed. Maize Cob (MC), Maize Husk, Maize Stover, and Maize Straw were degraded for 40 days using four different fungi: Pleurotus sajor-caju, Pleurotus pulmonarius, Lentinus subnudus, and Pleurotus tuber-regium. The substrates were analyzed for changes in the proximate composition and fibre fractions. In-Vitro Gas Production (IVGP) was used to predict the Metabolizable Energy (ME), Organic Matter Digestibility (OMD) and Short Chain Fatty Acids (SCFA). The MC and Pt were thereafter selected for in-vivo studies using twenty rams allotted to five groups of four rams per treatment in a completely randomized design. Each group was fed of the diets in which MC (g/100g) treated with Pt replaced wheat offal at 0(A), 25 (B), 50 (C), 75 (D) and 100 (E) as supplement to basal Panicum maximum in an experiment lasting 114 days. Parameters measured were Voluntary Dry Matter Intake (VDMI), Average Daily Weight Gain (ADWG), Feed Conversion Ratio (FCR), ruminal-pH, Total Volatile Fatty Acids (TVFA) and Ammonia-Nitrogen (NH3-N). The rams were sacrificed and data were obtained on Hot Carcass Weight (HCW) and Rib-Eye-Area (REA). Data collected were analyzed using ANOVA (p = 0.05). Fungal-degradation increased the crude protein from 6.8 to 9.4% while crude fibre, acid detergent fibre and acid detergent lignin were significantly reduced from 29.5 to 14.5% to 14.5, 49.9 to 40.7% and 15.8 to 11.2% respectively in MC. The IVGP, OMD, ME and SCF also improved significantly from 8.3 to 32.8ml, 38 to 52.6%, 5.2 to 7.7MJ/kg DM and 0.4 to 0.7�M respectively. Fungal- degradation significantly improved the VDMI (g) which increased consistently from 676.8 in rams on control diet to 709.4 for rams on diet E. The ADWG (g/d) recorded for rams ranged from 67.7 for rams on control diet to 88.8 for animals on diets E. The FCR and ruminat- pH for rams on diets A (9.99, 6.76), B (8.83, 6.74), C (8.34, 6.17), D (8.28, 6.70) and E (7.99, 6.45) were significantly lower compared with those on control diet. The TVFA (meq/L) increased from 10.1 to 12.8 in diets A to E. The NH3-N (mg/mL) also increased from 18.2 to 26.4 in diet A to E. Treatment effects on REA were significantly higher for those on bio-degraded diets compared with the control diet. The HCW (Kg) were 9.6, 12.0, 10.5, 10.2 and 10.7 for rams on treatments A, B, C, D and E respectively and was improved by fungal-degradation. Inclusion of maize cob treated with Pleurotus tuber-regium in the diet of rams improved the voluntary feed intake, digestibility, hot carcass weight and rib-eye-area. Biodegraded maize cob completely replaced wheat offal in the diet of West African Dwarf rams.