Effects of Orange (Citrus sinensis) Pulp-buffalo grass (Cenchruis cilliaris) silage on digestibility, growth performance and blood metabolites of windsnyer-type and large white x landrace crossed pigs

Abstract

The study evaluated the nutritive value of orange pulp- buffalo grass (OPBG) silage as a po-tential pig feed. In experiment 1, OPBG was ensiled in 58 one-litre jars, split into Reno-zyme® enzymes (containing α-amylases and β-endo 1, 3; 1, 4 beta glucanase) (denoted OPBGE) and 18 without enzyme (denoted OPBG). Samples were collected from the lab on days 7, 15 and 30 in a three by two factorial design (period by treatment). In Experiment 2, 12 South African Windsnyer-type (SAWIP) (27.2±3.9 kg) and 12 Large White- Landrace crosses (LW x LR) (28±9.8 kg) were fed diets containing different levels of bulk-ensiled OPBG ad libitum for 30 days, in a 2 X 3 (breed by level of OPBG (control, low (15% OPBG) and high (30% OPBG))) factorial arrangement. The apparent total tract digestibility (ATTD) of the pigs was measured during week 3 of feeding. The average body gain ABG average daily feed intake (ADFI), average daily gain (ADG), average gain to feed ratio (AG: F) were measured weekly. Serum glucose (GLU) , blood urea nitrogen (BUN), creatinine (CREAT), cholesterol, (CHOL) and triglycerides (TG) were measured during week 4 of the experiment. The levels of CP, EE, NDF, water soluble carbohydrates (WSC), lactic acid (LA) and pH were different (P<0.05) for OPBGE and OPBG on day 7. However the OPBGE concentra-tions of DM, ASH, CP, NDF, HEMI, WSC, LA and pH were higher (P<0.05) compared to OPBG. The OPBGE was lower (P<0.05) on EE and ADF, compared to OPBG on day 7. The levels of DM, ASH, CP, NDF, ADF, HEMI, LA and WSC were different (P<0.05) for OPBGE and OPBG on day 30. However the OPBGE levels of DM, CP, NDF, ADF, LA and WSC were higher (P<0.05) compared to OPBG. ASH, EE and HEMI were lower (P<0.05) on day 30. There were significant diets x day interactions (P<0.05) for DM, ASH, CP, EE, NDF, ADF, HEMI, WSC, and LA, but not for pH. The aerobic stability study was inconclusive. The digestibility levels of OM and NDF were different (P<0.05) for LW x LR and SAWIP, where LW x LR ATTD on OM and NDF was higher (P<0.05) compared to SAWIP for all diets. The LW x LR ADG was higher (P<0.05) compared to SAWIP for all diets. There was a diet x breed interaction effect (P <0.05) on ADG whereby the BUN and CREAT were different (P <0.05) for LW x LR and SAWIP. The SAWIP BUN was higher (P<0.05), but the CREAT and TG were lower (P<0.05) compared to LW x LR for all diets fed. In conclusion, OPBG inclu-sion in pig feed enhanced the quality of feed, digestibility, performance and blood metabo-lites profile.