In vitro ruminal fermentation with three sources of inoculum in diets containing Acrocomia aculeate

Abstract Text: The aim of this study was to determine the potential of different inoculum sources using in vitro gas production technique. Three different sources of inoculum were used for fermentation of gas production analysis: ruminal liquor from fistulated bovine grazing Brachiaria brizantha (LR); extracted from slaughtered pig cecum (CS); and cattle feces (FC) collected from the rectum and diluted with distilled water in 10% base. The substrate consisted in three diets content 100% of  Acrocomia aculeate pulp (AA), 20% AA pulp + 80% of basal diet (20AA) and 10% AA pulp + 90% of basal diet. The basal diet was composed by soy bean meal and corn grains to attempt pig growth requirements. The cumulative volume of gas produced was measured at 0, 3, 6, 9, 12, 16, 24, 48, 72 and 96 hours after incubation. The mathematical model used was described by France et al., (1993). The experimental design was one completely randomized blocks in factorial arrangement with eight repetitions (8x3x3).  All inoculums showed fermentative capacity and the time of colonization in each trial was lower (p<0.05) for CS followed by LR and FC, was 2.5, 3.2 and 3.7 hours, respectively. The substrate with higher potential of gas production was 20AA and presented lower value for FC (205.93 mL) and the difference between LR and CS (p<0.05) (265.05 mL and 299.23 mL). The rates for gas production were: AAxCS, AAxFR, AAxLR (0,0014 mL.-1h, 0,015 ml.-1h and 0,028 mL.-1h), 10AAxLR, 10AAxCS, 10AAxFR (0,0276 mL.-1h, 0,0410 mL.-1h and 0,0437 mL.-1h) and 20AAxFR, 20AAxLR, 20AAxCS (0,0351 ml.-1h, 0,0365 mL.-1h and 0,0432 mL.-1h) showed no statistical difference p>0.05). As a conclusion the CS inoculums can be used for the evaluation of gas production.

Keywords: gas production, alternative feed, biogas