scholarly journals In vitro screening as an anthelmintic discovery pipeline for Calicophoron daubneyi: nutritive media and rumen environment-based approaches

2021 ◽  
Vol 120 (4) ◽  
pp. 1351-1362
Author(s):  
K. M. Huson ◽  
R. M. Morphew ◽  
A. Winters ◽  
A. Cookson ◽  
B. Hauck ◽  
...  
Keyword(s):  
Western Europe ◽  
Rumen Fluid ◽  
In Vitro Screening ◽  
Screening Protocol ◽  
Compound Screening ◽  
Calicophoron Daubneyi ◽  
Tropical Climates ◽  
Discovery Pipeline ◽  
Production Losses

AbstractParamphistomosis can lead to morbidity and mortality of ruminant livestock within tropical and sub-tropical climates. In recent decades, rumen fluke has become an emerging infection in temperate climates across Western Europe, with Calicophoron daubneyi, the primary species present. Clinical outbreaks with C. daubneyi larvae are reported and adults might be responsible for production losses. There is not currently a widely licensed anthelmintic product available to control C. daubneyi. In this study, three existing flukicide anthelmintics were tested for efficacy against mature C. daubneyi, comparing a standard in vitro culturing assay and a new more relevant rumen fluid based in vitro compound screening protocol. The new rumen based screen confirmed that oxyclozanide was active against adult C. daubneyi and identified activity with praziquantel. The study highlighted the downstream value of incorporating relevant in vitro screening for anthelmintic discovery pipelines.

scholarly journals Optimized conditions for the in vitro excystment of Calicophoron daubneyi metacercariae

Parasitology ◽  
2017 ◽  
Vol 145 (8) ◽  
pp. 1015-1019 ◽  
Author(s):  
Kathryn M. Huson ◽  
Charlotte Wild ◽  
Caroline Fenn ◽  
Mark W. Robinson
Keyword(s):  
Western Europe ◽  
Trematode Species ◽  
Reducing Conditions ◽  
Significant Step ◽  
Basic Biology ◽  
Calicophoron Daubneyi ◽  
Optimized Conditions ◽  
Specific Parasite ◽  
Successful Production

AbstractParamphistomosis, caused by Calicophoron daubneyi, is an emerging infection of ruminants throughout Western Europe. Despite its prevalence, many questions remain regarding the basic biology of this parasite and how it interacts with its host. Consequently, there is a need to develop methods to study C. daubneyi in vitro to improve our understanding of rumen fluke biology. Towards this, we aimed to identify a suitable protocol for in vitro excystment of C. daubneyi metacercariae. Six methods that have been used to excyst metacercariae from a number of trematode species were tested with C. daubneyi metacercariae. Three of these achieved an average of >50% excystment whilst one method, which included an acid-pepsin treatment, incubation in reducing conditions and an alkaline/bile salt solution to activate the larvae, consistently gave >80% excystment. The latter protocol also showed no detrimental effect on the motility of newly excysted juvenile (NEJ) parasites when observed for up to 24 h in RPMI 1640 medium post-excystment. The successful production of C. daubneyi NEJs in vitro is a significant step forward, and will enable the discovery of infective stage-specific parasite antigens and facilitate drug screening trials, to aid the development of much needed diagnostic and therapeutic options for paramphistomosis.

In vitro screening of rumen fluid samples from indigenous African ruminants provides evidence for rumen fluid with superior capacities to digest tannin-rich fodders

1999 ◽  
Vol 50 (7) ◽  
pp. 1147 ◽  
Author(s):  
A. A. Odenyo ◽  
C. S. McSweeney ◽  
B. Palmer ◽  
D. Negassa ◽  
P. O. Osuji
Keyword(s):  
Leucaena Leucocephala ◽  
Rumen Fluid ◽  
Calliandra Calothyrsus ◽  
In Vitro Screening ◽  
Ammonia Production ◽  
Plant Leaves ◽  
Acacia Angustissima ◽  
Type Interaction ◽  
Fluid Sources

The capabilities of rumen fluid sources from indigenous African ruminants and hindgut fluid from zebra to ferment leaves of Acacia angustissima, Calliandra calothyrsus, Leucaena diversifolia, Leucaena leucocephala, Leucaena pallida, and Tephrosia bracteolata were evaluated to determine the presence of tannin tolerant or degrading microbes. In vitro gas and ammonia production and loss of neutral detergent fibre were estimated as indices for fermentation. The effect of polyethylene glycol (PEG) on fermentation was tested. The ability of microorganisms in rumen fluid sources to grow in the presence of tannin extracts or tannic acid was also tested and their disappearance was determined by HPLC. There was a significant (P < 0.001) rumen fluid source × fodder type interaction with all variables studied. The highest gas and ammonia production was from samples incubated with rumen fluid from dik-dik and goat. Addition of PEG enhanced fermentation with various rumen fluid sources and from some plant leaves but its effect was greatest (P < 0.001) in A. angustissima. HPLC results showed that tannin and phenolic monomers were hydrolysed by all rumen fluid sources. The conclusion from this work was that rumen fluid from goat, gazelle, Gunther™s dik-dik, and impala effectively fermented tannin-rich fodders and therefore may harbour tannin tolerant or degrading microorganisms.

Discovery of New AKT1 Inhibitors by Combination of In silico Structure Based Virtual Screening Approaches and Biological Evaluations

2019 ◽  
Author(s):  
Filip Fratev ◽  
Denisse A. Gutierrez ◽  
Renato J. Aguilera ◽  
suman sirimulla
Keyword(s):  
Virtual Screening ◽  
Success Rate ◽  
Protein Interactions ◽  
In Silico ◽  
Biological Data ◽  
In Vitro Binding ◽  
Vitro Binding ◽  
Screening Protocol ◽  
Screening Approaches

AKT1 is emerging as a useful target for treating cancer. Herein, we discovered a new set of ligands that inhibit the AKT1, as shown by in vitro binding and cell line studies, using a newly designed virtual screening protocol that combines structure-based pharmacophore and docking screens. Taking together with the biological data, the combination of structure based pharamcophore and docking methods demonstrated reasonable success rate in identifying new inhibitors (60-70%) proving the success of aforementioned approach. A detail analysis of the ligand-protein interactions was performed explaining observed activities.<br>

In Vitro Screening of Azalea for Resistance to Azalea Lace Bug

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506b-506
Author(s):  
Carol D. Robacker ◽  
S.K. Braman
Keyword(s):  
Leaf Damage ◽  
In Vitro Screening ◽  
Screening Assay ◽  
Delaware Valley ◽  
In Vitro Techniques ◽  
Culture Tube ◽  
Lace Bug ◽  
Lace Bugs ◽  
Laboratory Bioassays

Azalea lace bug (Stephanitis pyrioides) is the most serious pest on azalea. Results of laboratory bioassays and field evaluations of 17 deciduous azalea taxa have identified three resistant taxa: R. canescens, R. periclymenoides, and R. prunifolium. Highly susceptible taxa are `Buttercup', `My Mary', R. oblongifolium, and the evergreen cultivar `Delaware Valley White'. To determine whether in vitro techniques would have potential value in screening or selecting for resistance, or for the identification of morphological or chemical factors related to resistance, an in-vitro screening assay was developed. In-vitro shoot proliferation was obtained using the medium and procedures of Economou and Read (1984). Shoots used in the bioassays were grown in culture tubes. Two assays were developed: one for nymphs and one for adult lace bugs. To assay for resistance to nymphs, `Delaware Valley White' leaves containing lace bug eggs were disinfested with 70% alcohol and 20% commercial bleach, and incubated in sterile petri plates with moistened filter paper until the nymphs hatched. Five nymphs were placed in each culture tube, and cultures were incubated for about 2 weeks, or until adults were observed. To assay for resistance to adults, five female lace bugs were placed in each culture tube and allowed to feed for 5 days. Data collected on survival and leaf damage was generally supportive of laboratory bioassays and field results. Adult lace bugs had a low rate of survival on resistant taxa. Survival of nymphs was somewhat reduced on resistant taxa.

scholarly journals Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle

2021 ◽  
Author(s):  
B N Harsh ◽  
B J Klatt ◽  
M J Volk ◽  
A R Green-Miller ◽  
J C McCann
Keyword(s):  
Rumen Fluid ◽  
Block Design ◽  
Dietary Treatment ◽  
Feedlot Cattle ◽  
Nutrient Digestibility ◽  
Nitrogen Excretion ◽  
Distillers Grains With Solubles ◽  
Ractopamine Hydrochloride ◽  
Urinary Nitrogen

Abstract The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, twelve Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry rolled corn, 20% corn silage, 15% modified wet distillers grains with solubles, and 10% supplement. For each block, total collection of feed, orts, feces and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction (P &gt; 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect (P = 0.51) on DMI, but RAC had decreased fecal DM output (P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P &lt; 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P &lt; 0.01) than CON. Although treatment did not affect nitrogen intake (P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect (P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea (P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- (n = 9) and RAC-fed (n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split-plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD (P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. Inclusion of RAC in the in vitro substrate increased IVDMD (P &lt; 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter.

scholarly journals Feeding Value Assessment of Substituting Cassava (Manihot esculenta) Residue for Concentrate of Dairy Cows Using an In Vitro Gas Test

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 307
Author(s):  
Yuhui Zheng ◽  
Yanyan Zhao ◽  
Shenglin Xue ◽  
Wei Wang ◽  
Yajing Wang ◽  
...  
Keyword(s):  
Manihot Esculenta ◽  
Rumen Fluid ◽  
Gas Production ◽  
The Other ◽  
Holstein Cows ◽  
Value Assessment ◽  
Buffer Solution ◽  
Feeding Value ◽  
Cassava Residue

The feeding value of replacing concentrate with cassava (Manihot esculenta) residue in the feed of Holstein cows was confirmed using an in vitro gas test. The treatments consisted of 0% (control, CON), 5%, 10%, 15%, 20%, 25%, and 30% inclusion of cassava residue in fermentation culture medium composed of buffer solution (50 mL) and filtrated rumen fluid (25 mL). The parameters analyzed included the kinetics of gas production and fermentation indexes. Forty-eight hours later, there were no significant differences on in vitro dry matter disappearance (IVDMD), pH, and microbial crude protein (MCP) content among treatments (p > 0.05). However, the “cumulative gas production at 48 h” (GP48), the “asymptotic gas production” (A), and the “maximum gas production rate” (RmaxG) all increased linearly or quadratically (p < 0.01). The GP48 was significantly higher in the 25% treatment compared to the other treatments, except for the 30% (p < 0.01). The A was significantly larger in the 25% treatment compared to the other treatments, except for the 20% and 30% (p < 0.01). The RmaxG was distinctly larger in the 25% treatment compared to other treatments (p < 0.01); moreover, the “time at which RmaxG is reached” (TRmaxG) and the “time at which the maximum rate of substrate degradation is reached” (TRmaxS) were significantly higher in the 25% treatment than the CON, 20%, and 30% treatments (p < 0.01). Additionally, the content of ammonia-N (NH3-N) in all treatments showed linearly and quadratically decreases (p < 0.01), whereas total volatile fatty acid (VFA), iso-butyrate, butyrate, and iso-valerate contents changed quadratically (p = 0.02, p = 0.05, p = 0.01, and p = 0.02, respectively); all of these values peaked in the 25% treatment. In summary, the 25% treatment was associated with more in vitro gas and VFA production, indicating that this cassava residue inclusion level may be used to replace concentrate in the feed of Holstein cows. However, these results need to be verified in vivo.

scholarly journals Reducing enteric methane production from buffalo (Bubalus bubalis) by garlic oil supplementation in in vitro rumen fermentation system

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Avijit Dey ◽  
Shyam Sundar Paul ◽  
Puran Chand Lailer ◽  
Satbir Singh Dahiya
Keyword(s):  
Environmental Pollution ◽  
Methane Production ◽  
Rumen Fluid ◽  
Bubalus Bubalis ◽  
Rumen Fermentation ◽  
Acetyl Esterase ◽  
Garlic Oil ◽  
Enteric Methane ◽  
In Vitro Rumen Fermentation

AbstractEnteric methane production contributes significantly to the greenhouse gas emission globally. Although, buffaloes are integral part of livestock production in Asian countries, contributing milk, meat and draft power, the contribution of enteric methane to environmental pollution attracts attention. The present study investigated the efficacy of garlic (Allium sativum) oil in reducing enteric methane production from buffaloes (Bubalus bubalis) by in vitro rumen fermentation. Garlic oil (GOL) was tested at four concentrations [0 (Control), 33.33 µl (GOL-1), 83.33 µl (GOL-2) and 166.66 µl (GOL-3) per litre of buffered rumen fluid] in 100-ml graduated glass syringes and incubated at 39℃ for 24 h for in vitro rumen fermentation study. Supplementation of GOL-1 increased (p < 0.05) total gas production in comparison with GOL-3; however, it remained comparable (p > 0.05) with control and GOL-2. Graded doses of garlic oil inclusions reduced (p < 0.001) methane concentration (%) in total gas and total methane production (ml/g DM), irrespective of concentrations. The feed degradability, volatile fatty acids and microbial biomass production (MBP) were not affected (p > 0.05) by GOL-1, but these tended to decrease in GOL-2 with marked reduction (p < 0.01) in GOL-3. The decrease (p < 0.01) in NH3–N concentration in fermentation fluid in the presence of garlic oil, irrespective of concentration, suggests reduced deamination by inhibiting rumen proteolytic bacterial population. The activities of ruminal fibrolytic enzymes (CMCase, xylanase, β-glucosidase, acetyl esterase) were not affected by lower dose (GOL-1) of garlic oil; however, reduction (p < 0.05) of these enzymes activity in rumen liquor was evident at higher doses (GOL-2 and GOL-3) of supplementation. This study shows positive impact of garlic oil supplementation at low dose (33.33 µl/l of rumen fluid) in reducing enteric methane production, thereby, abatement of environmental pollution without affecting feed digestibility.

scholarly journals 49 Effects of in-vitro digestibility in cannulated steers when supplemented different levels of glycerol

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 55-56
Author(s):  
Noheli Gutierrez ◽  
Jamie A Boyd
Keyword(s):  
Dry Matter ◽  
Cold Water ◽  
Rumen Fluid ◽  
Latin Square ◽  
Optimal Level ◽  
Nutrient Digestibility ◽  
In Vitro Digestibility ◽  
Study Results ◽  
Different Levels

Abstract A study was conducted to evaluate effects of increasing concentration of food grade glycerol on rumen environment and nutrient digestibility. Three ruminally cannulated Jersey steers were used in this study. The study was conducted from March to May 2019. Experimental design was a 3x3 Latin square with a 2wk adjustment period followed by a 1wk collection period. Diet was coastal bermudagrass hay based. Different forage types were introduced in the incubation process to evaluate digestibility. Glycerol was administered once a day at 0, 15, or 20% of DMI (dry matter intake). dNDF (digestible NDF) and dDM (digestible dry matter) was determined using an ANKOM Daisy II incubator inoculated with 200g fresh rumen fluid and incubated for 12, 24, 48 and 72 h at 39°C. Each vessel contained ground forage samples in filter bags in triplicate. After incubation, filter bags were rinsed with cold water and dried for 24h in a 55°C forced air oven. Data were analyzed using the Proc MIXED procedure of SAS version 9.4. There was no difference dNDF in effect of different levels of glycerol between forage types by diet. But a numerical tendency was observed that dNDF was decreased at 20% inclusion rates in comparison to 0 and 15% inclusion of glycerol in the diet. Neither steer nor run was significantly different in the study. However as expected digestibility over time was significantly different (P &lt; 0.001). A significant increase was observed in DMI with the increased levels of glycerol in the diet (P = 0.003), both the 15% and 20% levels of glycerol increased in DMI in comparison to the control (0%). It appears based on these study results that digestibility may be inhibited, as levels of dietary glycerol increase in the diet and more work needs to be done to find the optimal level of glycerol supplementation.

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