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An experiment was carried out to investigate the effects of oxalic acid administration on feed intake and nutrient digestibility in goats. Four female cross bred (Boer × local) goats (average body weight of 46.3 kg) were randomly assigned to four experimental diets including oxalic acid administration at levels of 0, 2.25, 4.50 and 6.75 g/animal/d in a 4×4 Latin Square design. Oxalic acid diluted with water was administered orally via syringe to experimental goats once daily for four experimental periods. Each experimental period was lasted 21 d in length, comprising 14 d of adaptation to the experimental diet followed by 7 d of data collection. All the animals were individually fed with Napier grass ad libitum supplemented with 300 g (fresh basis) pelleted compound feed per goat per day throughout the study. Feed composition, feed intake, nutrient intake and nutrient digestibility were determined. Intakes of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF) and metabolisable energy tended to linearly decrease with the increasing rate of oxalic acid administration, with the value in the 6.75 g oxalic acid/animal/d treatment being significantly (p

To investigate the influence of different fertilization regimes on carbon dioxide (CO2) exchange and the effect of manure application on the carbon balance, we established two experimental plots, one with chemical fertilizers only and one with manure and supplementary chemical fertilizers, at each of four intensively managed grassland sites across the range of climate zones in Japan. By using eddy covariance CO2 flux and biometric measurements, we evaluated gross primary production (GPP), ecosystem respiration (RE), net ecosystem production (NEP), and the net ecosystem carbon balance (NECB), which accounts for carbon input through manure application and carbon loss through harvest. The sites in warmer zones showed larger annual GPP and RE, but annual NEP did not display any clear temperature dependence. The annual NEP was positive at all study sites and plots. The annual GPP and autotrophic respiration differed only slightly between the two plots despite the different fertilization regimes, but the decomposition of applied manure increased the annual heterotrophic respiration, thus causing a reduction in the annual NEP. At all the study sites, NECB of the plots with application of chemical fertilizers only was negative, indicating the loss of carbon. Manure application increased NECB, and its effect was larger at the cool temperate sites than at the temperate and warm temperate sites because of the greater amount of applied manure and larger sequestration rate at the cool temperate sites. Thus, manure application increased the accumulation of carbon in grassland, which is favorable from the viewpoint of ecosystem carbon management. Even when the enhanced nitrous oxide emission from the plots with manure application was taken into account, our findings suggest that manure application is a favorable option for mitigating greenhouse gas emission from Japanese grasslands and effectively managing livestock waste.

A survey of oxalate and its related mineral contents in selected fodder plants was conducted in two regions of subtropical Okinawa, Japan and of tropical Savar and Shahzadpur, Bangladesh. A total of 31 samples were taken from 13 fodder species in Okinawa, Southern part of Japan and of 63 samples from 27 fodder species in Bangladesh. The data of both regions revealed that the majority of fodder plants accumulated lower contents of oxalate than the critical level for toxicity at more than 20 g kg-1 DM, while few fodder species (Pennisetum purpureum and Brachiaria mutica) in Bangladesh and only Setaria sphacelatain southern part of Japan reached this critical level. In most of the cases, no relationship was found between oxalate and mineral contents in the plants tested. The results from the present study demonstrate that the oxalate content in tropical fodder species may vary in a wide range, mainly depending on plant species. To be noted is that some fodder species could accumulate oxalate at so high content as might be toxic to ruminants in certain conditions. © 2013 Academic Journals Inc.

The objectives of this study were to clarify the effect of chemical fertilizer and manure application on methane (CH4) and nitrous oxide (N2O) emissions from intensively managed grassland on Andosols in Japan and to determine the controlling factors of the CH4 and N2O emissions. The emission factors (EF) for both fertilizer- and manure-induced N2O emissions were calculated. Three experimental plots were set up in five grasslands across four climatic regions in Japan: one plot for treatment with chemical fertilizer (fertilizer plot); another plot for treatment with cattle manure and chemical fertilizer (manure plot), and the final plot was not treated with chemical fertilizer or manure (control plot). The type of chemical fertilizer was ammonium-based fertilizer or a combination fertilizer of ammonium and urea. CH4 and N2O emissions were measured at the study sites for six years. For the manure plot, a supplement of chemical fertilizer was added to equalize the supply rate of mineral nitrogen (N) relative ...

An experiment was conducted to investigate the effects of calcium (Ca) fertilization on oxalate content in napiergrass (Pennisetum purpureum) and on some blood parameters of sheep. Re-growth napiergrass was grown with or without Ca fertilizer and offered to sheep. Eight sheep, divided into two groups of 4 animals each were used. Calcium-fertilized napiergrass was offered daily to the animals as experimental treatment, whereas without Ca-fertilized napiergrass was given to the animals as control. Results showed that there was a trend to lower soluble and total oxalate concentrations in Ca-fertilized grass than control. The Ca-fertilized grass contained (p0.05) on Ca and Na concentrations in plants. Feeding of Ca-fertilized grass had no affect on the feed consumption, blood Mg level and daily gain of sheep. However, sheep fed control grass had lower (p

In order to determine whether oxalate from grasses affects feed intake, blood calcium (Ca) and other blood parameters of adult sheep, two feeding trials were conducted. In Trial 1, one group of sheep received guineagrass (0.47% soluble oxalate) and another group received setaria (1.34% soluble oxalate) for 28 d. In Trial 2, one group of sheep received guineagrass while another group received the same grass treated with an oxalic acid solution (at a rate of 30 g oxalic acid/kg dry matter of hay) for 72 d. All sheep received concentrate mixtures (0.5% of body weight) throughout the experiment. In both trials, it was observed that plasma Ca concentration (11.0-11.7 mg/dl) was significantly (p 0.05) were observed in concentrations of magnesium, phosphorus and parathyroid hormone in plasma between the feeding of low and high oxalate-containing grasses. In addition, no differences (p>0.05)

Oxalate occurs naturally in forage species, but excess levels of soluble oxalate adversely affect their nutritional quality as animal feed. Although induction of oxalate in plants has been associated with nitrate application, relatively little is known about oxalate in forage grasses. In the present study, we investigated oxalate accumulation and mineral uptake by napiergrass (Pennisetum purpureum, cv. dwarf-late) cultured in complete nutrient solution containing either solely nitrate or mainly ammonium as the main form of nitrogen. Total (shoot and root) yield of plants did not differ significantly between the nitrate and ammonium treatments. By contrast, the nitrogen form significantly affected oxalate accumulation and mineral uptake by plants. Nitrate application resulted in higher concentrations of soluble and insoluble oxalates in the shoot and soluble oxalate in the root than ammonium application. Nitrate application also resulted in higher concentrations of sodium and calcium in the shoot, and higher concentrations of sodium, calcium and magnesium in the root than ammonium application. The results suggest that the application of nitrate fertilizer as the sole source of nitrogen should be avoided in the cultivation of oxalate-rich forages, though further studies are needed under field conditions.

Ingestion of forage containing a large quantity of soluble oxalate can result in calcium deficiency and even death of livestock. Fertilization is one of the most practical and effective ways to improve yield and nutritional quality of forage. An experiment was conducted to determine the effects of nitrogen (N) fertilization (150, 300 and 600 kg/ha) across varying levels (150, 300 and 600 kg/ha) of potassium (K) on oxalate accumulation in napiergrass (Pennisetum purpureum). Application of N at 300 kg/ha produced higher dry matter yield than at 150 or 600 kg/ha, while K fertilization had no effect on yield. In general, N fertilization did not affect the soluble and total oxalate contents, but slightly affected the insoluble oxalate content. Soluble oxalate content showed an increasing trend and insoluble oxalate content showed a decreasing trend with increasing K level, but total oxalate content remained relatively constant. There were significant interactions between N and K fertilization for the content of soluble and insoluble oxalate fractions. The greatest increase in soluble oxalate content with N level at 300 kg/ha was found at the high level (600 kg/ha) of K application. The greatest increase in insoluble oxalate content with N level at 600 kg/ha was found at the low level (150 kg/ha) of K application. These results indicated the possibility of controlling the content of soluble and insoluble oxalate fractions in forage by fertilization.

Oxalate interferes with the absorption of calcium (Ca) in livestock. However, insoluble oxalate, which presents mostly as a complex combined with Ca, is not considered to be a problem in ruminants. The objective of this study was to test the possibility of increasing insoluble oxalate content in plants by increasing Ca supply in pot-grown napiergrass (Pennisetum purpureum Schumach). The plants were cut three times at approximately 2-month intervals from summer to autumn. Four treatments (0, 30, 60 and 90 g m−2) of Ca(OH)2 were applied in three equal split doses: before transplanting and soon after the first two cuttings. At almost all of the cuttings, soluble oxalate in forage showed a decreasing trend and insoluble oxalate and Ca concentration showed a reverse trend with an increased rate of Ca(OH)2 application. Averaged over the three cuttings, the 90-g Ca(OH)2 treatment was most effective in reducing soluble oxalate by increasing insoluble oxalate, with significant (P 0.05) by the rate of Ca(OH)2 application. Moreover, Ca(OH)2 application did not affect dry matter yield and the concentrations of magnesium, potassium and sodium of plant material. It may be concluded that the level of soluble oxalate in plants can be partially replaced by formation of insoluble oxalate using Ca(OH)2 fertilizer.

In a number of plant species, nitrogen fertilization leads to a higher oxalate content of the plant. Various tropical grasses sometimes contain oxalate in sufficient concentrations to induce calcium deficiency in grazing animals. The present study was undertaken to investigate the effect of increasing level of N (0, 10, 30, 60 and 90 g N m−2 using urea) on oxalate and some mineral contents in napiergrass (cv. dwarf-late). We found that the total dry matter yield increased significantly (P

We established a simple method for determination of oxalate in forage grasses using high-performance liquid chromatography (HPLC) with an anion analysis column (Shodex 1C SI-90 4E) and sodium hydrogen carbonate (NaHCO3) as eluent. Oxalate was determined after extraction with water or 1 mol HCl (soluble form or total, respectively). Insoluble oxalate was estimated as the difference between total oxalates and soluble form. Recovery of oxalate after HPLC was above 97%. Oxalates in forages could be successfully determined by this method. The method was simple, fast and inexpensive.

Oxalate concentration in forage plants is important, because it results mineral deficiency in ruminants. Data on oxalate concentration in forage plants in conjunction with cutting and uncutting conditions throughout the growing period are limited. This study was aimed to investigate the changes in oxalate and some mineral concentrations of setaria (Setaria sphacelata). The plants were harvested at different stages (vegetative, boot, pre-flowering, flowering and seed) of maturity and at about 50 cm in length of regrowth (second to sixth cuttings) for evaluation of soluble oxalate, insoluble oxalate and some mineral concentrations. Soluble oxalate and total oxalate concentrations, as well as mineral concentrations, decreased with advancing maturity. Both oxalate concentrations (soluble or insoluble) were higher in leaf compared to stem. Soluble oxalate and total oxalate concentrations of regrowth were the highest at third cutting and lowest at sixth cutting. Insoluble oxalate concentration of regrowth was almost similar in all cuttings, except for the sixth cutting. The highest concentrations of potassium, sodium and magnesium of regrowth were observed at third cutting, while the highest concentration of calcium was observed at sixth cutting. A relationship between oxalate and mineral concentrations was partially observed. Results suggest that cutting materials of setaria from June to October could achieve oxalate levels that are toxic to ruminants.

Various tropical grasses sometimes contain oxalate in sufficient concentration as to induce calcium deficiency in grazing animals. Napiergrass (Pennisetum purpureum), a useful tropical grass for ruminants was examined for oxalate levels with regard to season, variety and botanical fractions. It was observed that oxalate content was significantly (P

In a previous experiment, regenerated plants of bahiagrass (Paspalum notatum Flugge) derived from a suspension culture were observed to be higher in digestible cell wall content than compared to the control cultivar (cv. Pensacola). This suggested that somaclonal variation, mediated from suspension culture, could be a tool to induce improved feeding value of bahiagrass. In this study, dry matter production and digestibility of backcross 1 (BC1) progeny derived from this earlier study were examined in field conditions. The field study indicated that more than half of the BC1 individuals were higher in dry matter yield than the regenerated plants (RP), while most of the BC1 individuals were lower in dry matter yield than the original Pensacola cultivar (PEN). However, some strains of the BC1 exhibited a dry matter production that was comparable with PEN. Overall, in vitro dry matter digestibility (IVDMD) was generally higher in RP than in PEN. Although there was not a distinct difference in IVDMD between the BC1 and PEN, some BC1 individuals exhibited a higher IVDMD than PEN throughout the experiment. From these results, it is suggested that strains with higher digestibility could selected from BC1 progenies of bahiagrass following suspension culture and that trait is expressed in field conditions.

In order to evaluate the nutritive value of the forage plants in South Sulawesi, Indonesia, 266 samples (61 grasses and 65 legumes grown in the dry season, 60 grasses and 80 legumes grown in the rainy season) were collected from the highland and the lowland in 1998 to 2000, and were subjected to the determination of mineral composition. The mean contents of Ca, Mg, P, Na and K in grasses were 0.6, 0.3, 0.5, 0.1 and 2.3%, respectively, and in legumes were 1.8, 0.5, 0.8, 0.1 and 1.7%, respectively. The least-squares analysis of variance demonstrated as follows; For the grasses, Ca content was significantly affected by the yearxseason, yearxaltitude, and the seasonxaltitude interactions. Mg content was significantly affected by year and season and P content was significantly affected by altitude, year and by the yearxaltitude interaction. For the legumes, Ca content was significantly affected by altitude and the yearxseason, seasonxaltitude and the yearxaltitude interactions and Mg content was significantly affected by season or altitude and by the yearxseason interaction. These results indicate that Ca content of forage plants grown at the lowland in rainy season was higher than at the highland in dry season. Mg content of forage plants grown at the lowland in dry season was higher than at the highland in rainy season and P content of forage plants grown in the highland was higher than in the lowland.

In order to evaluate the nutritive value of the forage plants in South Sulawesi, Indonesia, 266 samples (61 grasses and 65 legumes grown in the dry season, 60 grasses and 80 legumes grown in the rainy season) were collected from the highland and lowland in 1998 to 2000, and were subjected to the determination of chemical composition and digestibility. The least-squares analysis of variance demonstrated that the in vitro dry matter digestibility (IVDMD) of grasses was not significantly affected by season or altitude. On the other hand, the some proximate components and cell wall components were significantly affected by season and altitude including the season×altitude interaction. For the legumes, the in vitro neutral detergent fiber digestibility (IVNDFD) and cellulose content were significantly affected by season. On the other hand, the ether extract (EE) content was significantly affected by season and altitude. The interaction of the season×altitude for IVDMD, of the year×season for some proximate components and of the year×season and the season×altitude for some cell wall components were significant. These results indicate that the forages grown at highland in dry season have a relatively high quality. The means of the total digestible nutrient (TDN) content estimated from IVDMD in grasses and in legumes were 50.3% and 57.4%, respectively, and the crude protein contents were 7.7% and 17.6%, respectively. The correlation coefficients between IVDMD and the contents of crude fiber, neutral detergent fiber and acid detergent fiber were relatively high in all of forage plants, suggesting that these components would provide an accurate prediction of digestibility or TDN content. A close relationship between IVNDFD and lignin content indicates that the lignin would be the most accurate predictor of cell wall digestibility. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 5 : 693-701)

The effects of an additive containing cell wall degrading enzyme on the ensilage losses were estimated under a farm condition. At ensiling Italian ryegrass with and without the additive, the nylon-net bags containing grasses were placed into each of the silage bulks. The bags were retrieved when the silages were unloaded, and their contents were subjected to the chemical analyses, in vitro digestion with rumen microbes and microscopic observation. Enzyme treatment improved the silage fermentation. The ensilage loss of cell wall components was highest in hemicellulose. In hemicellulosic monosaccharides, the loss of xylose was lowest, followed by uronic acids, arabinose, galactose and glucose. The losses in treated silage were significantly higher than the control silage in almost all the cell wall components. The losses of digestible-dry matter (DM) and digestible-neutral detergent fiber (NDF) in vitro were also significantly higher in the treated silage. The selective degradations of the readily digestible plant tissues (e. g. mesophyll and pith parenchyma) were observed in the treated silage.

Applying manure can lead to decrease of chemical nitrogen (N) fertilizer use and increase of soil carbon (C) sequestration. The effect of manure application on net ecosystem C balance (NECB), methane (CH4) and nitrous oxide (N2O) emissions and global warming potential (GWP) was examined at four managed grasslands on Andosols in different climatic regions in Japan for 3 years. At adjoining manure and fertilizer plots in each site, net ecosystem exchange (NEE) and CH4 and N2O fluxes were measured by the eddy covariance method and dark chamber methods, respectively. Manure application decreased fertilizer N application rate in manure plot to 65–88 % in fertilizer plot. NECB (= NEE−C applied in manure + harvested C) was higher in fertilizer plot (1.9 ± 0.9 MgC ha−1 year−1) than in manure plot (−1.8 ± 1.8 MgC ha−1 year−1), indicating that the soils in fertilizer plots lost C. There was no significant difference in harvested C between fertilizer and manure plots (4.3 ± 0.8 and 4.1 ± 0.6 MgC ha−1 year−1, respectively). NEE showed more CO2 uptake in fertilizer plots (−2.4 ± 1.1 MgC ha−1 year−1) than in manure plots (−1.6 ± 0.7 MgC ha−1 year−1), but manure application could compensate for the shortage in NEE. CH4 emission was close to zero, while the N2O emission was greater in manure plots (6.2 ± 3.7 kgN ha−1 year−1) than in fertilizer plots (3.6 ± 3.2 kgN ha−1 year−1). The difference of GWP between manure and fertilizer plots showed a negative relationship with manure C application rate (y = −4.45 ln(x) + 2.84; R 2 = 0.85; p < 0.01), indicating that manure application rate more than 2 MgC ha−1 year−1 can mitigate global warming in the Japanese grasslands.

We previously reported that cells other than mast cells or neurons could synthesize histamine in response to lipopolysaccharide (LPS) or interleukin 1beta in the rat brain. To identify the responsible cells, we examined histidine decarboxylase (HDC) activity and the expression of HDC mRNA in GMI 6-3 mouse microglial cells. Both the activity and mRNA for HDC in GMI 6-3 cells were induced by LPS treatment, and the induction was sensitive to calmodulin-dependent kinase II inhibitor, KN62. These findings indicate that microglia is a third cell type producing histamine in the brain.

We investigated the effect of lipopolysaccharide (LPS) and various inflammatory cytokines on the histidine decarboxylase (HDC) activity in cultured cells of the rat embryonic brain. Histaminergic neuronal cell bodies were supposed to exist in cultured cells of the diencephalon but not in those of the cortex. The HDC activity was elevated by adding LPS and interleukin-1 beta (IL-1beta) but not by tumor necrosis factor-alpha (TNF-alpha) and IL-6 to the mixed primary cultures of diencephalon. In the adherent cell fraction of the cultured diencephalon cells, HDC activity was also enhanced by LPS and IL-1beta. In a similar manner, LPS augmented HDC activity in the mixed primary culture of cerebral cortical cells and in its adherent cell fraction. The effects of IL-1beta but not LPS in the mixed primary culture of diencephalon were canceled by a prior exposure to cytosine-beta-D-arabinofuranoside. The changes in HDC activity after exposure to LPS for 12 h were not accompanied by increased mRNA levels. In these cell cultures, mast cells were not detected by Alcian Blue staining. These results indicated the presence of the third type of HDC-bearing cell besides neurons and mast cells in the brain. The increase of HDC activity by IL-1beta might be due to cell proliferation.

We have previously demonstrated the increase of histidine decarboxylase activity and histamine content in the murine hypothalamus after intracerebroventricular injection of lipopolysaccharide possibly due to inducible interleukin-1 beta (IL-1 beta). Therefore, we investigated the effects of IL-1 beta on brain histamine dynamics by directly injecting it into the tuberomammillary nucleus of the rat hypothalamus (TM) using an in vivo microdialysis method. Injection of artificial cerebrospinal fluid or recombinant murine IL-1 beta at 0.1 ng into the TM did not evoke a significant change in core temperature, however, a significant monophasic febrile response was observed following injection of IL-beta at more than 1 ng per animal. Histamine release in the anterior hypothalamic area in vivo was significantly augmented from 140 min to 360 min following injection of IL-1 beta at 10 ng dose. These results suggest the possibility that interrelationship between histamine and IL-1 beta may modulate the acute phase reaction in the central nervous system.

An experiment was conducted to evaluate the effects of nitrogen (N) level on the dry matter (DM) yield, N concentration and oxalate content of some tropical grasses, namely Rhodesgrass (Chloris gayana), Guineagrass (Panicum maximum) and Sudangrass (Sorghum vulgare). Three levels of N as urea were applied (Standard- 260, Standardx2- 540 and Standardx4- 1,060 kg N/ha for Rhodesgrass; Standard- 380, Standardx2- 770 and Standardx4- 1,570 kg N/ha for Guineagrass and Sudangrass) in a completely randomized design and grasses were harvested twice at approximately two-month intervals. Dry matter yield tended to be higher with increased rate of N fertilizer in all species, while further additional N (Standardx2 or Standardx4) did not significantly (p>0.05) further increase DM yield, when compared with the Standard level of N fertilizer application. There was also a trend towards higher N concentration in plants as N fertilization increased in all species and it was increased significantly in Rhodesgrass and Sudangrass (p 0.05) differences on oxalate content in plant tissue within species, when compared with the Standard level of N. The Rhodesgrass contained 0.11, 0.13 and 0.15% soluble oxalate and 0.23, 0.25 and 0.27% total oxalate with Standard, Standardx2 and Standardx4 level of N application, respectively. The Guineagrass contained 0.54, 0.50 and 0.42% soluble oxalate and 1.60, 1.56 and 1.45% total oxalate with Standard, Standardx2 and Standardx4 level of N application, respectively. The Sudangrass contained 0.06, 0.15 and 0.12% soluble oxalate and 0.22, 0.22 and 0.21% total oxalate with Standard, Standardx2 and Standardx4 level of N application, respectively The results from this study suggest that these grasses do not use further addition of N fertilizer (Standardx2 or Standardx4) to form high content of oxalate salts, when compared with the Standard level of N. In addition, the levels of oxalate present with these grasses are quite low as far as toxicity to animals is concerned.

Sodium is involved in elevation of oxalate content in some plant species and this element is abundant in saline soils. Oxalate causes precipitation of insoluble calcium oxalate in the rumen and kidneys. The intention of this study was to evaluate the effect of soil salinity stress on dry matter yield and oxalate content in pot-grown napiergrass (Pennisetum purpureum Schumach). Plants were cut three times at 56, 118 and 179 d after transplanting to the pots. Five salinity treatments were used containing various concentrations of NaCl solution as follows: 0, 100, 300, 600 and 900 mM. At 28, 42, 84, 98, 146 and 160 d after transplanting, plants were irrigated with one liter of the particular treatment for each application. Dry matter yield of napiergrass was not affected (p>0.05) by salinity treatments. Plants treated with 100 mM NaCl exhibited a higher soluble oxalate content compared to other treatments, but the differences were not statistically significant (p>0.05). Although salinity treatments had significant (p