Abstract:
The pressure on maize for livestock feeding has necessitated the use of non-conventional feedstuff such as sweetpotato as alternative feed resource. Sweetpotato root is limited by nutrient quality when compared to maize. However, the composite of root and vine could enhance the nutrient quality. Current information on formulation based on sweetpotato composite for rabbit feeding is insufficient. Therefore, effect of composites of sweetpotato on growth and reproductive performance of rabbit were investigated.
Roots and vine of sweetpotato varieties (White-Fleshed-WF (TIS87/0087) and Orange-Fleshed-OF (CIP440293)) were analysed for total carotenoids (µg/mL), tannin (mg/100g), saponin (mg/100g), Crude Protein-CP, Ether Extract-EE and Crude Fibre-CF using standard procedures. Composites of vine and root (35:65) of each of WF and OF were used to replace maize in rabbit diets at: 0%-Control, 25%OF, 50%OF, 75%OF, 25%WF, 50%WF and 75%WF. Weaner rabbits (n=84), aged 7-8 weeks, weighing 567.6±13.7g were randomly allotted to the diets in triplicates of four rabbits/replicate and fed ad-libitum for 72 days. Feed intake-FI (g), survivability, Dressing Percentage-DP, CP and CF digestibility were determined using standard procedures. Does (n=25), aged 6-7 months, weighing 2169.8±150.01g were randomly allotted to five treatments: control, 25%OF, 50%OF, 25%WF and 50%WF with five replicates, in a completely randomised design. Body Weight Before Gestation-BWBG (g), Body Weight at Parturition-BWP (g), Post Gestation Feed Intake-PGFI (g), and Litter Size at Birth-LSB were recorded. Data were analysed using descriptive statistics and ANOVA at α0.05.
Total carotenoids in OF (2,182.3±40.2) and WF roots (2,057.4±90.4) were significantly higher than 1,511.9±100.5 and 1,297.9±122.7 in the corresponding OF and WF vine. Tannins 0.03±0.2 of WF vine were higher than 0.02±0.1 (OF root), 0.02±0.1 (WF root) and 0.02±0.03 (OF vine). Saponins ranged from 0.3±0.04 (WF vine) to 0.41±0.1 (OF root) while CP of 11.5±0.3 (OF) and 11.4±0.6 (WF) vine were higher than 8.1±0.6 (OF) and 5.3±0.3 (WF) roots. Vine CF value of 6.9±0.3 (WF) was significantly higher than 6.6±0.1 (OF) vine, 6.4±0.3 (OF) root and 5.7±0.2 (WF) root. Diets 25%OF, 25%WF and control resulted in similar FI of 50.1±1.6, 48.0±2.1 and 59.2±4.9, while 50%OF, 75%OF, 50%WF and 75%WF had lower FI of 43.1±3.4, 40.1±1.8, 37.3±2.2 and 33.8±3.1, respectively. Survivability of 91.7±1.4% in control, 25% (OF) and 25% (WF) were higher than 75.0±1.6% (50%OF), 66.7±0.8% (50%WF), 58.3±0.6% (75%OF) and 58.3±0.6% (75%WF). The DP ranged from 49.5±0.9% (75%OF) to 58.6±4.7% (50%WF). Crude protein digestibility of 82.3±2.5% (50%OF) was higher than 77.1±3.6 (25%WF), 75.4±3.7 (75%WF), 75.3±0.5 (Control), 73.2±2.1 (50%WF), 73.1±2.4 (25%OF) and 72.1±1.6 (75%OF), while CF digestibility ranged from 25%WF (13.3±2.2%) to 75%OF (19.5±1.1%). The BWBG ranged from 2,041.8±256.2 (25%WF) to 2,408.8±321.8 (Control) while BWP ranged from 2,214.2±102.2 (WF 50%) to 2,707.0±122.5 (Control). The PGFI of 126.9±3.1 (25%WF) and 126.4±2.4 (25%OF) were higher than 124.2±3.1 (50%OF), 123.4±2.1 (50%WF) and 121.2±1.6 (control) while LSB ranged from 4.0±0.9 (50%OF) to 5.0±0.7 (25%WF;50%WF), showing the synergistic influence between composites of sweetpotato and LSB.
Orange-fleshed sweetpotato vine and root composites successfully replaced maize in rabbit diets. The nutrient digestibility, overall growth and reproductive performance were enhanced.
