Effect of ruminal fibrolytic bacteria on Invitro dry matter and organic matter disappearance of wheat straw and rice straw

Abstract

The objective of this research was to study the effect of two strains of fibrolytic bacteria (Thermonospora fusca and Acetobacter xylinum) on wheat straw or rice straw in anaerobic condition. The experimental bacterial treatments were consisted of untreated wheat straw or rice straw as control (T1), wheat straw or rice straw treated with Thermonospora (T2), wheat straw or rice straw treated with Acetobacter (T3) . The changes in chemical composition and cell wall constituents were studied in ensiled wheat straw or rice straw. Silage was made from wheat straw or rice straw incubated for two months to investigate the effect of replacing concentrate feed mixture(CFM) by untreated and bacterial treated wheat straw or rice straw at 50, 60, 70 and 80%( resulting in rations from R1 to R24) on Invitro DM and OM disappearance and the regression coefficient was rate of disappearance (unit per hour). Data showed that bacterial treatment for wheat straw or rice straw significantly (P<0.05) increased CP from 4.48% or 1.92 in control (T1) to 14.98 and 15.54% or 14.46 and 12.92% in T2 and T3 respect., while decreased CF from 46.99% or 45.09% in untreated (T1) to 36.11 and 32.14 % or 29.45 and 38.23 % in treated T2 and T3, respectively. Bacterial treatments decreased hemicellulose and cellulose for wheat or rice straw treated significantly decreased compared with untreated(T1) . The rations containing different percentage of treated wheat straw or rice straw with Thermonospora fusca and Acetobacter xylinum, individually, increased Invitro DM and Invitro OM disappearance (P<0.05) compared to control(T1). Data indicated that ,after 48hrs,Invitro DM and OM digestibility of wheat straw or rice straw in untreated rations were not significant in R1, R2, R13 and R14(contain50%and 60%untreatedstraw) while rations were significant in R4 and R16(contain 80%untreated straw) . Data showed that Invitro DM digestibility after 48 hrs, the highest values found in R12 and R24 (63.00 and 57.28 %)which contain 80% treated straw with Acetobacter, while the lowest values was found in R5 and R17 (60.37 and 49.71%,respectively) which contain 50% treated straw with Thermonospora, but in R9 was record low value approximately as R5 (contain 50% treated straw with Acetobacter) . Values of Invitro OM digestibility of wheat straw rations after 48 hrs increased in R12(65.88%) also in rice straw rations were record that R24 ( 60.85 %)which contain 80% treated straw with Acetobacter while it decreased in R5 and R17 ( 61.44 and 56.99%) which contain 50% treated straw with Thermonospora.The rate of DM disappearance (unit /hour)in experimental rations recorded the highest values in R6 and R20 (1.0635 and 0.9839 unit/hour, respect.)which contain treated straw with Thermonospora (60% treated wheat and 80% treated rice, respect.) but the lowest value in R1 and R15 (0.9910 and 0.7734 unit/hour, respect.) which contain untreated straw( 50% untreated wheat and 70% untreated rice, respect.) It can be concluded that, the bacterial treatments with Thermonospora and Acetobacter had more effect on chemical composition and cell wall constituents of wheat straw and rice straw compared with untreated one. The treatments with fibrolytic bacteria could be used to improve the quality of wheat straw and rice straw through decreasing fibrous fraction and increasing protein, Invitro DM , OM disappearance especially when rations contained 80 % treated straw with Acetobacter while the rate of disappearance was improved in rations contained treated straw with Thermonospora in the experimental rations.