Design, Synthesis, and Herbicidal Evaluation of Pyrrolidinone-Containing 2-Phenylpyridine Derivatives as Novel Protoporphyrinogen Oxidase Inhibitors.

In this work, a series of pyrrolidinone-containing 2-phenylpyridine derivatives were synthesized and evaluated as novel protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4) inhibitors for herbicide development. At 150 g ai/ha, compounds 4d, 4f, and 4l can inhibit the grassy weeds of Echinochloa crus-galli (EC), Digitaria sanguinalis (DS), and Lolium perenne (LP) with a range of 60 to 90%. Remarkably, at 9.375 g ai/ha, these compounds showed 100% inhibition effects against broadleaf weeds of Amaranthus retroflexus (AR) and Abutilon theophrasti (AT), which were comparable to the performance of the commercial herbicides flumioxazin (FLU) and saflufenacil (SAF) and better than that of acifluorfen (ACI). Molecular docking analyses revealed significant hydrogen bonding and π-π stacking interactions between compounds 4d and 4l with Arg98, Asn67, and Phe392, respectively. Additionally, representative compounds were chosen for in vivo assessment of PPO inhibitory activity, with compounds 4d, 4f, and 4l demonstrating excellent inhibitory effects. Notably, compounds 4d and 4l induced the accumulation of reactive oxygen species (ROS) and a reduction in the chlorophyll (Chl) content. Consequently, compounds 4d, 4f, and 4l are promising lead candidates for the development of novel PPO herbicides.

Diurnal Variation in Forage Nutrient Composition of Mixed Cool-Season Grass, Crabgrass, and Bermudagrass Pastures.

Warm-season grasses have been suggested as alternative low non-structural carbohydrate (NSC) pasture forages. The purpose of this study was to evaluate nutrient composition and diurnal changes in soluble carbohydrates for the warm-season annual 'Quick-N-Big' crabgrass [CRB; Digitaria sanguinalis (L.) Scop.] and the warm-season perennial 'Wrangler' bermudagrass [BER; Cynodon dactylon (L.) Pers] in comparison to mixed cool-season grass [CSG; 'Inavale' orchardgrass (Dactylis glomerata [L.]), 'Tower' tall fescue (Lolium arundinaceum [Schreb.] Darbysh.), and 'Argyle' Kentucky bluegrass (Poa pratensis [L.])]. Samples were collected at 4-hour intervals over 3 d when each forage reached the boot stage of maturity. Digestible energy was greatest for CSG (2.29 ± 0.34 Mcal/kg) and lowest for BER (2.13 ± 0.34 Mcal/kg), while crude protein was lowest for CSG (16.1 ± 0.29%) and neutral detergent fiber was greatest for BER (60.0 ± 0.41; P ≤ .0008). Non-structural carbohydrates were greater for CSG (17.6% ± 0.26%) compared to BER (10.6% ± 0.26%) or CRB (10.9% ± 0.26%; P < .0001). Overall, NSC was greatest in the afternoon and evening (14.5-14.9 ± 0.60%) and lowest in the early morning (11.2-11.4 ± 0.60%; P ≤ .04), but diurnal variation was most pronounced in CSG versus either Warm-season grasses. Results of this study provide needed data on nutritional composition of CRB and BER and demonstrate that these grasses may serve as pasture forages for horses where NSC intake is of concern. Results also support recommendations for restricting grazing to early morning to limit NSC consumption, particularly in CSG pastures.

Fonio grains: Physicochemical properties, nutritional potential, and food applications.

Fonio grains are a type of small-seeded cereals native to Western Africa and are important cereal crops for food security. The two species are white fonio (Digitaria exilis) (commonly called acha) and black fonio (Digitaria iburua) (commonly called iburu). As a novel food, fonio has attracted attention from other parts of the world due to their attractive nutritional properties (e.g., in whole grain form and being gluten free) and potential food applications. The information regarding the functional properties and applications of fonio is rather scattered. This review summarizes the chemical composition, physicochemical and nutritional properties, and diverse food applications of fonio. The nutritional composition and processing properties of fonio are similar to other cereals. Fonio has potential to be complementary to major cereals for diverse food uses. There are research opportunities to better explore fonio grains for value-added applications.

Aqueous extract of Digitaria exilis grains ameliorate diabetes in streptozotocin-induced diabetic male Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The absence of scientific data on the age long folkloric use of Digitaria exilis grains by sufferers of diabetes prompted the present investigation. This study was aimed at evaluating the antidiabetic activity of aqueous extract of Digitaria exilis grains in streptozotocin (STZ)-induced diabetic rats. MATERIAL AND METHODS: Forty two male rats (166.43 ±â€¯3.32 g) were completely randomized into six groups (A-F) of 7 animals each. Animals in group A (control) were administered 0.5 ml of distilled water while those in groups B, C, D, E and F which were induced with diabetes mellitus (by intraperitoneal administration of 60 mg/kg body weight of STZ) were also administered distilled water, 50 mg/kg body weight of metformin (a reference antidiabetic drug), 50, 100 and 200 mg/kg body weight of aqueous extract of D. exilis grains respectively, twice daily for 14 days. Blood glucose levels and some relevant biomolecules were determined 14 days post-administration. RESULTS: Alkaloids, flavonoids, saponins, tannins, anthraquinones, terpenoids, cardiac glycosides, phlobatannins, phenolics and cardenolides were detected in the extract with alkaloids (30.20 mg/ml) occurring the most and phlobatannins (0.22 mg/ml) the least. Streptozotocin significantly (p < 0.05) increased the levels of blood glucose, serum albumin, urea, creatinine and cholesterol, activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase in the liver and intake of feed and water. Body weight, weight of pancreas, pancreatic insulin, liver glycogen content, red blood cell and white blood cell and their related indices, liver hexokinase and phosphofructokinase activities were significantly reduced by STZ. In contrast, the extract significantly reversed all those STZ-treatment induced changes with the 200 mg/kg body weight of the extract producing profound values that compared favourably with the distilled water treated non-diabetic animals and metformin treated diabetic animals. CONCLUSION: Overall, this study revealed that Digitaria exilis grains possess antidiabetic activity via increased insulin secretion, as plasma concentrations of insulin were not determined, enhanced activities of hexokinase and phosphofuctokinase and repletion of hepatic glycogen content.

In vitro acaricide and anticholinesterase activities of digitaria insularis (Poaceae) against Rhipicephalus (Boophilus) microplus.

Medicinal plants have been proposed as an alternative for acaricide control, aiming to develop lower-cost and eco-friendly ectoparasiticide products. The aim of this study was to evaluate the in vitro activity of the extracts and fractions obtained from the leaves of Digitaria insularis on the reproductive efficacy of the bovine tick Rhipicephalus (Boophilus) microplus. Also, we investigated the possible relation with the anticholinesterase mechanism. The effect of the crude hydroethanolic (CH), hexanic (HE), ethyl acetate (EA), butanolic (BT) and residual hydroethanolic (RH) extracts, as well as four fractions of HE, were evaluated using adult immersion test. Only the HE and EA extracts (50 mg/mL) and fraction 2 (Fr2) (12.5 mg/mL) promoted reduction of the reproductive parameters (oviposition and hatching rate) greater than 90% and were not statistically different from the positive control. Higher reproductive activity was recorded in Fr2 with a lower effective concentration (EC50) value (6.65 mg/mL) than in HE (17.8 mg/mL) and EA (23.97 mg/mL). The anticholinesterase activity was assessed through spectrophotometry in microtiter assays, with enzymatic inhibition of 34.8, 43.2 and 57.9% of the HE, AE and Fr2, respectively. The chemical evaluation of the Fr2 was carried through Gas Chromatography coupled to Mass Spectrometry (GC-MS) and led to the characterization of nine compounds classified as fatty acids (3), esterified fatty acids with long-chain alcohol (4) and terpene (1). The effect of D. insularis extracts and fractions was focused on female reproductive parameters such as oviposition and hatching rates. The results obtained in this study suggest that D. insularis shows an in vitro acaricidal activity against R. (B.) microplus. Such action might be associated with the presence of secondary metabolites identified in the Fr2.

In vitro anthelmintic and cytotoxicity activities the Digitaria insularis (Poaceae).

This study aimed to evaluate the in vitro activity of D. insularis extracts and fractions against gastrointestinal nematodes of goats and its cytotoxicity on Vero cells. The egg hatch (EHT) and larval motility (LMT) tests were conducted to investigate the anthelmintic effects of the crude hydroethanolic (CH), ethyl acetate (EA), butanolic (BT) and residual hydroethanolic (RH) extracts. The elution of the active extract (EA) on column chromatography (SiO2) using organic solvents furnished six fractions (FR1 to FR6), which were also tested. Cytotoxicity was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Trypan Blue exclusion assays. All extracts, FR2 and FR3, inhibited egg hatching in a concentration-dependent manner. The EHT led to EC50 values (effective concentration 50%) of 0.64; 0.69; 0.77; 0.96; 0.27 and 0.65mg/mL for CH, EA, BT, RH, FR2 and FR3, respectively. However, the extracts exhibited low effect on the motility of L3. In the cytotoxicity evaluation (MTT assay), the IC50 (inhibitory concentration 50%) was 1.18 (EA), 1.65 (FR2) and 1.59mg/mL (FR3), which was relatively high (low toxicity) in comparison to the EC50 values in EHT, mainly for FR2. The chemical analyses of most active fractions (FR2) by Liquid Chromatography coupled to Mass Spectrometry (LC-MS) led the characterization of the flavones tricin and diosmetin. These results showed the high anthelmintic effect and low cytotoxicity of D. insularis and also that the flavones can be probably responsible for the nematocidal activity of this plant.

New Cytotoxic Alkylated Chalcones from Fatoua villosa.

Three new alkylated chalcones, villosins A - C (1 - 3), five known analogues, together with ten known coumarins, were isolated from Fatoua villosa. The structures of the new compounds were elucidated by extensive spectroscopic analysis, including 1D-, 2D-NMR, and MS data. Compounds 1 - 3 showed cytotoxicity against five kinds of human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7) with IC50 values ranging from 1.4 ± 0.1 to 5.7 ± 0.3 µm.

Effect of varying degrees of succinylation on the functional and morphological properties of starch from acha (Digitaria exilis Kippis Stapf).

Scientific data on the effect of varying degrees of succinylation on starch from Acha, an underutilized source is scanty. Bridging this gap is the focus of this study. Acha starch was extracted, succinylated (succinic anhydride (SA) (3-14 g/100g starch) and the degree of substitution determined. Proximate composition and functional characteristics of both native and succinylated starches were evaluated according to standard methods. Starch spectra and morphology were also studied. Succinylation increased (5.63-11.68%) with increasing concentration of SA. Amylose peaked at 36.42% and thereafter decreased to 28.84%. Swelling power and solubility increased in multiple folds especially at temperatures (70-90°C) at all levels of substitution (0.1-0.20). Pasting viscosities (165.9-307.5 RVU) decreased and did not follow the order of substitution. Morphology (polygonal) and granular sizes (6-12 µm) among the succinylated and native starches were not significantly different (P<0.05). Succinylated Acha starches hold great promise as a good and cheaper replacement for gums in Food Applications.

Assessing the enrichment of heavy metals in surface soil and plant (Digitaria eriantha) around coal-fired power plants in South Africa.

Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1836 ± 70 µg g(-1), 0.08 ± 0.05 to 1744 ± 29 µg g(-1), and 0.07 ± 0.04 to 1735 ± 91 µg g(-1) in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005 ± 0.003 to 535 ± 43 µg g(-1) in Matla, 0.002 ± 0.001 to 400 ± 269 µg g(-1) in Lethabo, and 0.002 ± 0.001 to 4277 ± 201 µg g(-1) in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4-5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005-0.65), except for Pb that showed moderate to strong pollution (1.74-2.53).

Dephytinisation with intrinsic wheat phytase and iron fortification significantly increase iron absorption from fonio (Digitaria exilis) meals in West African women.

Low iron and high phytic acid content make fonio based meals a poor source of bioavailable iron. Phytic acid degradation in fonio porridge using whole grain cereals as phytase source and effect on iron bioavailability when added to iron fortified fonio meals were investigated. Grains, nuts and seeds collected in Mali markets were screened for phytic acid and phytase activity. We performed an iron absorption study in Beninese women (n = 16), using non-dephytinised fonio porridge (FFP) and dephytinised fonio porridge (FWFP; 75% fonio-25% wheat), each fortified with (57)Fe or (58)Fe labeled FeSO4. Iron absorption was quantified by measuring the erythrocyte incorporation of stable iron isotopes. Phytic acid varied from 0.39 (bambara nut) to 4.26 g/100 g DM (pumpkin seed), with oilseeds values higher than grains and nuts. Phytase activity ranged from 0.17±1.61 (fonio) to 2.9±1.3 phytase unit (PU) per g (whole wheat). Phytic acid was almost completely degraded in FWFP after 60 min of incubation (pH≈5.0, 50°C). Phytate∶iron molar ratios decreased from 23.7∶1 in FFP to 2.7∶1 in FWFP. Iron fortification further reduced phytate∶iron molar ratio to 1.9∶1 in FFP and 0.3∶1 in FWFP, respectively. Geometric mean (95% CI) iron absorption significantly increased from 2.6% (0.8-7.8) in FFP to 8.3% (3.8-17.9) in FWFP (P<0.0001). Dephytinisation of fonio porridge with intrinsic wheat phytase increased fractional iron absorption 3.2 times, suggesting it could be a possible strategy to decrease PA in cereal-based porridges.

Crabgrass (Digitaria sanguinalis) allelochemicals that interfere with crop growth and the soil microbial community.

Three chemicals, veratric acid, maltol, and (−)-loliolide, were isolated from crabgrass and their structures were identified by spectroscopic analysis. The chemicals were detected in crabgrass root exudates and rhizosphere soils, and their concentrations ranged from 0.16 to 8.10 µg/g. At an approximate concentration determined in crabgrass root exudates, all chemicals significantly inhibited the growth of wheat, maize, and soybean and reduced soil microbial biomass carbon. Phospholipid fatty acid profiling showed that veratric acid, maltol, and (−)-loliolide affected the signature lipid biomarkers of soil bacteria, actinobacteria, and fungi, resulting in changes in soil microbial community structures. There were significant relationships between crop growth and soil microbes under the chemicals' application. Chemical-specific changes in the soil microbial community generated negative feedback on crop growth. The results suggest that veratric acid, maltol, and (−)-loliolide released from crabgrass may act as allelochemicals interfering with crop growth and the soil microbial community.

Effect of cooking on the total antioxidant capacity and phenolic profile of some whole-meal African cereals.

BACKGROUND: At present, sorghum, fonio and millet are not placed as important commodities in the North American and European food basket, but their importance as ingredients in multigrain and gluten-free cereal products is highlighted. Therefore in this study the phenolic profile (evaluated by liquid chromatography/tandem mass spectrometry), total phenolic content (assessed by Folin-Ciocalteu assay) and total antioxidant capacity were measured in three African whole grains, i.e. sorghum (Sorghum bicolor ssp. bicolor), fonio (Digitaria exilis) and pearl millet (Pennisetum glaucum L.), before and after a cooking procedure. RESULTS: After the cooking process, soluble phenolic acids increased significantly in sorghum, whereas bound ones and anthocyanins decreased significantly. In millet the cooking process significantly enhanced soluble phenolic acids without affecting those bound, whereas in fonio a slight but significant decrease in almost all soluble phenolic acids was observed along with a significant increase in bound ones. Finally, the cooking process negatively affected both total phenolic content and total antioxidant capacity. CONCLUSION: This is one of the few reports dealing with the antioxidant compounds of these three African whole grains in which the effect of cooking was also evaluated. The data suggested that, to improve their antioxidant properties, specific cultivars should be selected and the cooking procedures carefully considered.

Utilization of African grains for sourdough bread making.

UNLABELLED: Acha and Iburu flours were singly subjected to sourdough fermentation with previously selected autochthonous starters. Sourdoughs were used (30%, wt/wt) as aroma carriers and acidifiers during short time fermentation with the addition of baker's yeast. Acha and Iburu sourdough breads were compared to wheat sourdough bread started with the same strains and to breads made with the same formula but using baker's yeast alone. During Acha and Iburu sourdough fermentations, starter lactic acid bacteria reached almost the same cell density found in wheat sourdoughs. Acidification was more intense. Iburu sourdough bread had the highest total titratable acidity, the lowest pH, and contained the highest levels of free amino acids and phytase activity. The values of in vitro protein digestibility did not differ between Acha sourdough and wheat sourdough breads, while Iburu sourdough bread showed a slightly lower value. Acha and Iburu sourdough breads showed lower specific volume and higher density with respect to wheat sourdough breads. Nevertheless, Acha and Iburu sourdough breads were preferred for hardness and resilience. As shown by sensory analysis, Acha and especially Iburu sourdough breads were appreciated for color, acid taste and flavor, and overall acceptability. PRACTICAL APPLICATION: This study was aimed at evaluating the technological and nutritional properties of the African cereals Acha and Iburu. Sourdough fermentation and the use of selected starters increased the nutritional and sensory qualities and the potential application for bakery industry.

Exploitation of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours: chemical characterization and their use for sourdough fermentation.

This study aimed at characterizing the chemical and microbiological composition of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours and at exploiting their potential for sourdough fermentation. Both the flours had a gross composition similar to other cereals. As shown by two-dimensional electrophoresis analysis, Acha flour had a higher number of prolamins with respect to Iburu flour. The opposite was found for the number of glutelin spots. The concentration of total free amino acids of Iburu flour was higher than that of Acha flour (1348±34 vs. 100±20 mg/kg). Pediococcus pentosaceus was the dominant species in both the flours. Several isolates were used to ferment Acha or Iburu flours. After 8h fermentation at 30°C, pH ranged from 3.41 to 3.83 and from 4.20 to 4.66 for Acha and Iburu sourdoughs, respectively. The highest values of TTA and concentration of lactic acid were found in almost all Iburu sourdoughs. The synthesis of acetoin and γ-amino butyric acid (GABA) was only found in Iburu sourdoughs. Data from the kinetics of acidification, synthesis of lactic and acetic acids, acetoin, and liberation of total free amino acids were elaborated by Principal Component Analysis. Sourdoughs from Acha and Iburu flour were clearly differentiated.

Effect of malting conditions and quality characteristics of malt and roasted malt extract from 'acha' grains (Digitaria exilis Stapf).

BACKGROUND: Considering the importance of malting and roasting on the quality of 'acha' beverages, a study was conducted to find optimum conditions for malting and the production of a high-quality roasted extract that could be used for an 'acha' beverage. RESULTS: The data obtained were analysed using response surface methodology. The results revealed that the most significant (P < 0.05) malting factors that affect the response variables were the linear terms of germination time and drying temperature. However, for the extract production, the linear term of roasting temperature was the most significant (P < 0.05) factor. The quadratic and interaction terms exhibited significant (P < 0.05) effect in all cases apart from the flavour. CONCLUSION: The overall optimum regions were established at 28 h of germination time, 55 degrees C drying temperature and 5.0% moisture content for the malting conditions while for the extract production, a roasting temperature of 210 degrees C, extraction temperature of 70 degrees C and extraction duration of 20 min were established.

Comparison of fecal crude protein and fecal near-infrared reflectance spectroscopy to predict digestibility of fresh grass consumed by sheep.

Organic matter digestibility (OMD), an essential criterion for the evaluation of the nutrition of ruminants, cannot be measured easily at pasture. Therefore, the objective of this study was to test and compare 2 methods of OMD prediction based on the fecal CP content (CPf) or near infrared reflectance spectroscopy (NIRS) applied to feces. First, published equations derived from fecal N (Eq. 1(CP), n = 40) and from fecal NIRS (Eq. 1(NIRS), n = 84) were used to predict OMD of an independent validation data set from which in vivo OMD, ranging from 58 to 74%, was measured for 4 regrowth stages of Digitaria decumbens. Second, to establish equations usable in grazing situations and to improve the efficiency of the predictions, new equations were calculated from a large data set (n = 174) using CPf (Eq. 2(CP)) or fecal NIRS (Eq. 2(NIRS)). By applying the CPf method, Eq. 2(CPf) (OMD, % = 88.4 - 263.9/CPf, % of OM; residual SD = 2.92, r(2) = 0.63) showed similar statistical parameters (P < 0.01) when compared with Eq. 1(CP) (OMD, % = 86.6 - 266.2/CPf, % of OM; residual SD = 2.95, r(2) = 0.79). When using fecal NIRS, Eq. 2(NIRS) showed decreased SE of calibration (SEC = 1.48) and of cross-validation (SECV = 1.75) and greater coefficient of determination of cross-validation (R(2)(CV) = 0.85) than the previously published Eq. 1(NIRS) (SEC = 1.78, SECV = 2.02, R(2)(CV) = 0.77). The validation of the 4 equations on the validation data set was satisfactory overall with an average difference between the predicted and the observed OMD ranging from 0.98 to 2.79 percentage units. The Eq. 2(NIRS) was nevertheless the most precise with a decreased residual SD of 2.53 and also the most accurate, because the SD of the average difference between predicted and observed OMD was the lowest. Therefore, fecal NIRS provided the most reliable estimates of OMD and is thus a useful tool to predict OMD at pasture. However, an adequate number of reference data are required to establish good calibration. Indeed, better calibration statistics were obtained by increasing the data set from 84 (Eq. 1(NIRS)) to 174 (Eq. 2(NIRS)). In contrast, using fecal N on a set of 84 or 174 points did not improve the prediction. Both methods are useful for predicting OMD at pasture in certain circumstances, using fecal NIRS when a large data set (n = 84 and n = 174) is available and fecal CP with smaller data sets (n = 40).

Effect of crabgrass (Digitaria ciliaris) hay harvest interval on forage quality and performance of growing calves fed mixed diets.

Twelve 0.81-ha crabgrass (Digitaria ciliaris [Retz.] Koel.) hay fields were harvested at 21, 35, and 49 d of regrowth (average phonological growth stage of 30, 51, and 56, respectively). Increased harvest interval exhibited a linear decrease (P < 0.01) in CP (14.1, 13.7, and 10.6% of DM, respectively) and increase (P < 0.01) in NDF (65.3, 70.6, and 70.2% of DM, respectively) and ADF (35.7, 38.9, and 42.7% of DM, respectively). Hays were incorporated into 3 diets that contained 20% (DM basis) crabgrass hay, ground corn (33%), and soybean hulls (32%). Diets contained 14.4, 14.4, and 13.6% CP; 1.83, 1.72, and 1.81 Mcal of NE(m)/kg; and 1.21, 1.10, and 1.17 Mcal of NE(g)/kg; respectively. Diets were fed to beef calves in 12 pens at a rate of 2.3% (DM basis) of BW in 1 experiment (n = 120, initial BW 210 +/- 4.4 kg) and ad libitum in another experiment (n = 60, initial BW 207 +/- 4.4 kg). To measure passage rate of the hay and concentrate portions of the diets, 12 heifer calves (BW = 145 +/- 4.5 kg) were individually fed at 2.3% of BW for 14 d and dosed with Dy-labeled soybean hulls and Yb-labeled hay. In situ DM digestibility of the hays and diets were determined using 3 ruminally cannulated steers (BW = 584 +/- 10.4 kg). Harvest interval did not affect (P > or = 0.11) ADG of limit-fed calves during the diet acclimation or growing phases (average 0.32 and 0.80 kg, respectively) or ADG of calves fed ad libitum (average 1.21 kg). Dry matter intake of calves fed ad libitum averaged 7.9 kg/d (3.28% of BW) and was not affected (P > or = 0.22) by harvest interval. Gain:feed was not affected (P > or = 0.20) by harvest interval (0.13 and 0.15 for limit-fed and ad libitum-fed calves, respectively). Increased harvest interval linearly increased (P < 0.01) ruminal retention time of the hay and tended (P = 0.06) to linearly increase ruminal retention time of the concentrate portions of the diet. Harvest interval linearly decreased (P < or = 0.05) the extent of degradability and effective degradability of DM and NDF of hays, but DM disappearance of the total diet did not differ (P > or = 0.35). In the conditions of this study, increasing harvest interval of crabgrass hay from 21 to 49 d had no deleterious impact on animal performance or efficiency of gain when fed to growing calves in a high-concentrate mixture.

Ruminal in situ disappearance kinetics of nitrogen and neutral detergent insoluble nitrogen from common crabgrass forages sampled on seven dates in northern Arkansas.

Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often an undesirable species in field and forage crops, but visual observations suggest that livestock prefer it to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11 and August 22, 2001 and then to determine ruminal in situ disappearance kinetics of N and neutral detergent insoluble N (NDIN) for these forages. A secondary objective was to compare these kinetic estimates for crabgrass with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and or-chardgrass (Dactylis glomerata L.) as control hays. All kinetic evaluations were conducted with 5 ruminally cannulated Gelbvieh x Angus x Brangus steers (383 +/- 22.7 kg). Concentrations of N for crabgrass decreased linearly (P < or = 0.002) across sampling dates for leaf, stem, and whole-plant tissues. Conversely, percentages of the total N pool within NDIN and ADIN fractions generally increased over sampling dates in mostly linear patterns. For crabgrass, the immediately soluble portion of the total N pool (fraction A; overall mean = 54.6% of N) was greater (P < 0.001) than for all control hays. Crabgrass exhibited a more rapid N disappearance rate (overall mean = 0.093/h; expressed as a proportion disappearing/h) than that of bermudagrass (0.046/h; P < 0.001), but the disappearance rate for alfalfa N (0.223/h) was considerably faster (P < 0.001) than for crabgrass. The effective ruminal disappearance of N was greater (P < 0.001) for crabgrass (overall mean = 85.4%) than for the alfalfa (83.3%), bermudagrass (72.3%), or orchardgrass (76.0%) control hays. For alfalfa, the ruminal disappearance rate of NDIN (0.150/h) was more rapid (P < 0.001) than for crabgrass (overall mean = 0.110/h); however, the disappearance rate for crabgrass was faster than that for bermudagrass (0.072/h; P < 0.001) or for orchardgrass (0.098/h; P = 0.010). Effective ruminal disappearance of NDIN was greater (P < 0.001) for crabgrass (overall mean = 72.0%) than for the bermudagrass (69.0%) or alfalfa hays (50.5%), but there was no difference (P = 0.865) between crabgrass and orchardgrass (72.1%). Although crabgrass forages exhibited concentrations of total N that were comparable with those of alfalfa and rates of ruminal N disappearance that were < 50% of those for the alfalfa hay control, improvements in N use efficiency relative to alfalfa are questionable because of the excessively large Fraction A for crabgrass.

Ruminal in situ disappearance kinetics of dry matter and fiber in growing steers for common crabgrass forages sampled on seven dates in northern Arkansas.

Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often viewed as an undesirable weed, largely because it encroaches upon field and forage crops, gardens, and lawns. However, visual observations of livestock grazing mixed-species pastures suggest that cattle seem to prefer crabgrass to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11, and August 22, 2001, and then to determine ruminal in situ disappearance kinetics of DM and NDF for these crabgrass forages. A secondary objective was to compare these kinetic estimates with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and orchardgrass (Dactylis glomerata L.) control hays. All forages were evaluated in situ using five (383 +/- 22.7 kg) ruminally cannulated crossbred (Gelbvieh x Angus x Brangus) steers. Whole-plant crabgrass exhibited more rapid (P < or = 0.002) ruminal disappearance rates of DM (overall range = 0.069 to 0.084 h(-1)) than did bermudagrass (0.054 h(-1)) and orchardgrass (0.060 h(-1)) hays, but disappearance rates were slower (P < 0.001) for crabgrass than for alfalfa hay (0.143 h(-1)). Effective ruminal disappearance of DM was greater (P < 0.001) for crabgrass (overall range = 69.3 to 75.4%) than for all the control hays. Similarly, disappearance rates of NDF for crabgrass (overall range = 0.069 to 0.086 h(-1)) were more rapid (P < 0.001) than observed for bermudagrass and orchardgrass hays; however, NDF in alfalfa disappeared at a faster (P < 0.001) rate (0.107 h(-1)) than crabgrass. These results indicate that crabgrass offers greater effective ruminal degradability of DM and NDF than orchardgrass or alfalfa of moderate quality. More importantly, it potentially offers faster and more extensive ruminal disappearance than perennial warm-season grasses typically found throughout the southeastern United States, and it should likely support improved performance by ruminant livestock in this region.

A simple procedure for preparing substrate for Pleurotus ostreatus cultivation.

The use of wooden crates for composting a mixture of 70% grass, (Digitaria decumbens), and 30% coffee pulp, combined with 2% Ca(OH)(2), was studied as a method for preparing substrate for the cultivation of Pleurotus ostreatus. Crate composting considerably modified the temperature pattern of the substrate in process, as compared to pile composting, where lower temperatures and less homogeneous distributions were observed. Biological efficiencies varied between 59.79% and 93% in the two harvests. Based on statistical analysis significant differences were observed between the treatments, composting times and in the interactions between these two factors. We concluded that it is possible to produce P. ostreatus on a lignocellulosic, non-composted, non-pasteurized substrate with an initial pH of 8.7, and that composting for two to three days improves the biological efficiency.