Nutrient intake and digestibility of graded dietary levels of dried cassava peel meal as replacement for maize offal fed to goats

Abstract

The study was undertaken to determine the nutrient intake and digestibility of graded dietary levels of dried cassava peel meal (CPM) as replacement for maize offal fed to West African dwarf (WAD) goats. Four (4) intact WAD bucks aged 1-2 years with mean initial body weight of 16.00 ± 0.71kg were used for the study. Four diets were formulated with cassava peel meal replacing maize offal at 0, 60, 80 and 100 %, designated T₁, T₂, T₃ and T₄, respectively. Each of the animals received one of the four (4) treatment diets in a 4 x 4 Latin Square design. The data obtained from this study were subjected to analysis of variance (ANOVA) applicable to a 4 x 4 Latin Square design experiment. The results on proximate composition of the diets showed that significant differences (P<0.05) existed in crude protein, ash, crude fiber, ether extract and metabolizable energy (ME), whereas no significant differences (P>0.05) were observed in dry matter and nitrogen – free extract (NFE). The control diet had significantly (P<0.05) higher crude protein (CP), ash, ether extract (EE) and metabolizable energy than the other treatments except for crude fiber of T₄ and ME of T₂. The T₄ group had the highest (P<0.05) crude fiber. The dry matter intake as percentage body weight was significantly (P<0.05) higher in T₂ among the treatments with T₃ recording the lowest value. Diets T₁, T₂ and T₄ had similar (P>0.05) N-intake (g/d/Wkg^0.75), N- absorbed (g/d/Wkg^0.75) and apparent nitrogen digestibility values. The animals fed T₂ had significantly higher (P<0.05) urinary-nitrogen (g/d) and urinary- N (g/d/Wkg^0.75) than those fed the other treatment diets, whereas the control (T₁) recorded the lowest (P<0.05) values in these parameters. The N – intake (g/d), urinary – N output (g/d) and apparent nutrient digestibility coefficients differed significantly (P<0.05) among the treatment groups. The dry matter, crude protein, crude fiber, ether extract and nitrogen – free extract were better digested (P<0.05) in the control diet (T₁) than in the CPM diets. The metabolic faecal nitrogen (MFN) values were similar (P>0.05) in all the diets. The values for endogenous urinary nitrogen (EUN) were 0.689, 1.403, 0.880 and 0.956 (g/d/Wkg^0.75) for T₁, T₂, T₃ and T₄, respectively. The Biological values were 95.46, 89.33, 90.89 and 92.76 for T₁, T₂, T₃ and T₄, respectively. The diet (T₄) containing 100% CPM is recommended among the other CPM diets for feeding goats, as it had better performance with respect to nutrient digestibility and utilization.

Keywords: Nutrient, intake, digestibility, cassava peel meal, maize offal, goats