The Effect of Monensin or Protexin on Gas Production Parameters of Alfalfa and Barley in the Ruminal Fungi Culture

Introduction Since the legislation of European Union has prohibited the use of growth-promoting antibiotics such as: monensin, there is an interest in alternatives to manipulate the rumen fermentation. The use of growth-promoting antibiotics in animal feeds is banned in Europe due to having potential risks such as the spread of antibiotic resistance genes or the contamination of milk or meat with antibiotic residues. Recently, probiotics have been increasingly evaluated to replace or facilitate reductions in the use of antibiotics. Thus, the aim of this study was investigating the comparison of antibiotic (sodium monensin) and probiotic (protexin) on the gas production parameters and organic matter digestibility of feedstuffs (alfalfa hay, barley grain, and alfalfa barley mixture)
Materials and Methods Experimental treatments were included control (basal feeds without additive), basal feeds supplemented with sodium monensin or protexin probiotic at levels of 500 or 1000 mg per kg of DM in a rumen fungi culture. Ruminal fluid was collected from two fistulated sheep (49.5±2.5 kg) and all samples were withdrawn 2 h after the morning ration had been consumed. Collected ruminal contents were strained through four layers of cheesecloth and brought immediately to the laboratory. To have a pure ruminal fungi culture, whole ruminal fluid was centrifuged at 1000 g for 10 min and added 0.100 mg/ml antibacterial agent (streptomycin sulfate, penicillin G, and chloramphenicol (14, 35). Gas production technique was used to detect the fermentation parameters of the treatments (16).Three parallel syringes of each treatment were prepared in this experiment. To measure the total gas production (A) and the rate of gas production (c), cumulative gas production, organic digestibility and metabolizable energy of treatments until 120 h. Gas production was measured directly from the volume of the syringes at 0, 3, 6, 16, 24, 48, 72, 96, and 120 h. Statistical analysis of data were statistically analyzed in a completely randomized design was performed by SAS (9.1 version) and the least square of means.
Results and Discussion Results showed the higher level of sodium monensin (1000 mg/kg) decreased fermentable fraction (b), organic digestibility and metabolizable energy of both alfalfa hay and barley grain compared with other treatments significantly. The total gas production (A) and the rate of gas production (c) of gas production, cumulative gas production, organic digestibility and metabolizable energy of alfalfa were highest for control treatment (alfalfa without additives). But the level of 1000 mg/kg of protexin supplemented with barley increased fermentable fraction (b), cumulative gas production, organic digestibility and metabolizable energy than other treatments by ruminal fungi (p