Seasonal Dry Matter Production and Nitrogen Fixation of Leucaena (Leucaena Leucocephala) and Stylo (Stylosanthes Guianensis) in Pure Swards and in Association with Signal Grass (Brachiaria Decumbens)

An experiment was conducted to study the effects of rates of fertiliser nitrogen (N) and grass-legume associations on seasonal and annual dry matter production and forage quality factors of signal grass (Brachiaria decumbens). This study was also designed to es timate the amounts of N2 fixed over the first two years of establishment by pure stands of leucaena (Leucaena leucocephala cv. ML 1) and stylo (Stylosanthes guianensis cv. Schofield) or their mixtures with signal grass. Leucaena and s tylo were either grown in pure swards or mixed in various combinations wi th signal grass unfertilised with N. Dry matter production from legumebased pasture was compared with signal grass fertilised with urea at 0, 200, 400, 600 or 800 kg N ha-1yr-1

Evaluation of grass quality in grazing and ungrazing paddocks in a Buffalo Breeding and Research Centre, Telupid, Sabah, Malaysia

Buffalo production is dependent almost entirely on forages. Thus, adequate nutrition plays important role in the productivity of buffaloes. In Buffalo Breeding and Research Centre, Telupid, Sabah, Malaysia, Signal Grass (Brachiaria decumbens) is fed to buffaloes. Since the growth of the buffalo depends on the nutritional quality of grass provided to them, this study was undertaken to evaluate the nutrient contents of signal grass to determine its quality. In addition, a comparison was made on the nutrient contents between signal grass obtained from the grazing and non-grazing areas. Six grass samples each was obtained from grazing and non-grazing areas. The grass samples were taken using the quadrat and all the samples were air-dried and sent to Universiti Pertanian Malaysia for proximate analysis. The dry matter (DM) and crude protein (CP) were determined. The values of Van Soest Fibre were also determined, to include neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). The results revealed that the DM and CP were significant (p<0.05) higher in grass from grazing than non-grazing area. There was also significant (p<0.05) negative correlation between DM and CP contents of signal grass. In conclusion, the grass in grazing area has better nutritive value compared to grass in non-grazing area. In addition, the relationship between DM and CP was inversely related, that is as DM increases CP decreases. The results of the current study could be used to improve the performance of farm and as a reference for future study

Toxic effects of Pb2+ on the growth and mineral nutrition of signal grass (Brachiaria decumbens) and Rhodes grass (Chloris gayana)

Although grasses are commonly used to revegetate sites contaminated with lead (Pb), little is known regarding the Pb-tolerance of many of these species. Using dilute solution culture to mimic the soil solution, the growth of signal grass (Brachiaria decumbens Stapf cv. Basilisk) and Rhodes grass (Chloris gayana Kunth cv. Pioneer) was related to the mean activity of Pb2+ {Pb2+} in solution. There was a 50% reduction in fresh mass of signal grass shoots at 5 mu M {Pb2+} and at 3 mu M {Pb2+} for the roots. Rhodes grass was considerably more sensitive to Pb in solution, with shoot and root fresh mass being reduced by 50% at 0.5 mu M {Pb2+}. The higher tolerance of signal grass to Pb appeared to result from the internal detoxification of Pb, rather than from the exclusion of Pb from the root. At toxic {Pb2+}, an interveinal chlorosis developed in the shoots of signal grass (possibly a Pb-induced Mn deficiency), whilst in Rhodes grass, Pb2+ caused a bending of the root tips and the formation of a swelling immediately behind some of the root apices. Root hair growth did not appear to be reduced by Pb2+ in solution, being prolific at all {Pb2+} in both species

Nitrogen fluxes from irrigated common-bean as affected by mulching and mineral fertilization.

The objective of this work was to measure the fluxes of N2O&#8209;N and NH3&#8209;N throughout the growing season of irrigated common&#8209;bean (Phaseolus vulgaris), as affected by mulching and mineral fertilization. Fluxes of N2O&#8209;N and NH3&#8209;N were evaluated in areas with or without Congo signal grass mulching (Urochloa ruziziensis) or mineral fertilization. Fluxes of N were also measured in a native Cerrado area, which served as reference. Total N2O&#8209;N and NH3&#8209;N emissions were positively related to the increasing concentrations of moisture, ammonium, and nitrate in the crop system, within 0.5 m soil depth. Carbon content in the substrate and microbial biomass within 0.1 m soil depth were favoured by Congo signal grass and related to higher emissions of N2O&#8209;N, regardless of N fertilization. Emission factors (N losses from the applied mineral nitrogen) for N2O&#8209;N (0.01?0.02%) and NH3&#8209;N (0.3?0.6%) were lower than the default value recognized by the Intergovernmental Panel on Climate Change. Mulch of Congo signal grass benefits N2O&#8209;N emission regardless of N fertilization

Effect of Phenobarbitone Treatment Against Signal Grass (Brachiaria decumbens) Toxicity in Sheep

The effect of phenobarbitone against signal grass (Brachiaria decumbens) toxicity was studied in 26 male crossbred sheep. Grazing on signal grass significantly decreased the concentration of cytochrome P-450 and the activity of drug metabolizing enzymes, viz. aminopyrine-N-demethylase, aniline-4-hydroxylase, UDP- glucuronyltransferase and glutathione-S-transferase in liver and kidneys of affected sheep. Oral administration of phenobarbitone (30 mg/kg body weight) for five consecutive days before grazing on B. decumbens pasture, and thereafter, for three consecutive days every two weeks, resulted in significant increases in hepatic and renal activities of drug-metabolizing enzymes. The induction of drug metabolizing activity in sheep grazing on signal grass group was found to be lower than in animals given phenobarbitone alone. Induction by phenobarbitone provided a degree of protection against the toxic effects of B. decumbens as indicated by the delay in the appearance of signs of toxicity. Furthermore, these were much milder compared to those in the sheep not treated with phenobarbitone. The present study suggests that phenobarbitone-type cytochrome P-450 isoenzyme-induction may increase resistance against signal grass (B. decumbens) toxicity in sheep

Protective Effect Of Phenorbarbitone And Griseofulvin Againt Signal Grass (Brachiaria Decumbens)Toxiciti In Sheep

The protective effect of phenobarbitone and griseofulvin against signal grass (B. decumbens) toxicity were studied in fifty-three Wiltshire x Malin (Indigenous Malaysian) male sheep. Twenty-six animals were used in phenobarbitone experiment and twenty-seven animals were used in griseofulvin experiment. Grazing on signal grass significantly decreased the concentration of cytochrome P-4S0 and the activity of drug metabolizing enzyme, viz. aminopyrine-N-demethylase, aniline-4- hydroxylase, UDP-glucuronyltransferase and glutathione-S-transferase in liver and kidney of sheep. The concentration of cytochrome P-4S0 was determined in microsomal fraction according to the method of Omura and Sato (1964a) as described by Mazel (1971). The activities of aminopyrine-N-demethylase and aniline-4- hydroxylase were determined using Mazel, 1971 method by estimating th

Toxic Effects Of Signal Grass (Brachiaria Decumbens) On Drug- Metabolizing Enzyme Activities In Sheep

Signal grass (Brachiaria decumbens) is widely grown on livestock farms in many countries including Malaysia due to its high productivity and nutritive value. Unfortunately, it is toxic to sheep and goats causing a severe hepatic and renal damage, and death. Two experiments were conducted to determine the effect of the toxicity of signal grass (B. decumbens) on the activity of drug-metabolizing enzymes (DME) in sheep and cattle. It was hypothesized that the activities of selected enzymes would be affected during intoxication and that differences in the activity level of the enzymes in the two species might explain why cattle were safe from the toxic effect of the grass. Twenty-three healthy Wiltshire-Malin crossed rams, aged 1 4- 1 6 months were used, fifteen for the first experiment and eight for the later. In the first experiment, aniline 4-hydroxylase (A4H), aminopyrine N-demethylase (AND), UDP-glucuronyl transferase (UDPGT), glutathione S-transferase (GST) and cytochrome P450 of the liver and kidney of the control and intoxicated sheep wer

Phenotypic Variability of Brachiaria Decumbens After Exposure to Gamma Irradiation

Brachiaria decumbens (Signal grass) has been used for many years as grazing pastures for ruminants. Its toxicity to small ruminants is the main limitation to utilization of this grass. Many researchers have reported several methods to control or alleviate this problem. Since there is a potential to use mutagenesis techniques to obtain variability of the plants, the objective of this study is to observe the phenotypic variability of Signal grass after mutagenic induction with gamma radiation. Further studies can be conducted to make a selection of variants which are free from toxicity. Brachiaria decumbens seeds were irradiated at doses of 1 00, 200, 300, 400, 500, 600, 700, 800 and 900 Gy to determine the appropriate doses for mutagenic treatments of the grass. The results showed that, B. decumbens seeds were less sensitive to gamma ray than most other species and the LD50 was found to be between 800 to 900 Oy. In order to observe the effects of gamma radiation on phenotypic variability of the grass, the grass seeds were exposed to 900 Oy gamma radiation. Results showed that gamma radiation at 900 Oy increased variability in morphological characteristics and nutrient contents and an obvious phenotypic mutant was detected. There were significant increases in variabilities of morphological characters (tiller numbers, leaf length, leaf width, leaf weights, stem weights., leaf-to-stem ratio and internode lengths) and nutrient contents (Crude Protein, Ether Extract, Crude Fibre, Acid Detergent Fibre, Neutral Detergent Fibre and Ash) among the treated plants. There was also a positive skew of the frequency distribution curve for the treated plants to the right, indicating that mutagenic radiation can cause increased variability, which allows greater selection potential for desired characteristics. DNA Polymorphism in the mutant cannot be detected through RAPD. The mutant showed significantly higher leaf width, leaf-to-stem ratio and crude protein compared to control plants