• Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.180-194
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• 2024

Mass mortalities of mud crab Scylla spp. larvae due to pathogenic Vibrio spp. outbreaks have frequently occurred in hatcheries. To overcome this problem, probiotics containing Bacillus subtilis bacteria are applied to inhibit pathogenic ones. We tested different doses of probiotic-containing B. subtilis (10⁸ CFU/g) on the Scylla tranquebarica larvae and investigated the microbiota population, including Vibrio. Water quality, larvae development, and crablet production were also monitored. The recently hatched larvae were grown in twelve conical fiber tanks filled with 200 L sterile seawater, with a salinity of 30 ppt at a stocking density of 80 ind/L. Four different doses of probiotics were applied in the larvae rearing, namely, A = 2.5 mg/L, B = 5 mg/L, C = 7.5 mg/L, and D = 0 mg/L, with three replicates. Next-generation sequencing analysis was used to obtain the abundance of microbes in the whole body of megalopa and the water media for larvae rearing after applying probiotics. Sixteen Raw Deoxyribonucleic Acid samples (eight from a whole body of megalopa extraction from four treatments of probiotics defined as A, B, C, D, and eight from water media extraction from four treatments of probiotic defined as E, F, G, H) were prepared. Then, they were sent to the Genetics Science Laboratory for NGS analysis. Ammonia, nitrite, total organic matter (TOM), larvae, and crablet production were monitored. Based on the Next-generation sequencing analysis data, the Vibrio spp. decreased significantly (p < 0.05) than control test (D) in megalopa-applied probiotics at the doses of 2.5 mg/L (A) and 7.5 mg/L (C) and in the water media for megalopa rearing treated with probiotics at the dosage of 5.0 mg/L (F). Ammonia in the zoea stage in B treatment and TOM in the zoea and megalopa stage in B and C treatments were decreased significantly (p < 0.05). It impacts the higher number of zoea survival in treatments B and C. Finally, it results in a significantly high crablet production in treatments B and C. Therefore, the dosage of 5 mg/L to 7.5 mg/L improves crablet S. tranquebarica production significantly.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1429-1437
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• 2003

Browse tree legume leaves from Acacia spp (A. nilotica, A. tortilis, A. polyacantha), Dichrostachys sp, Flagea villosa, Piliostigma thonningii, Harrisonia sp were evaluated for nutritive potential (chemical compositions and degradability characteristics) compared to Gliricidia sepium. Effect of tannins anti-nutritive activity on digestibility was also assessed by polyethylene glycol (PEG) tannin bioassay. Crude protein (CP), ash, neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) differed (p<0.05) between legume foliages. Mean CP, ash, NDF, ADF and ADL for fodder species tested were 158, 92, 385, 145, and 100 g/kg DM, respectively. CP ranged from 115 (P. thonningii) to 205 g/kg DM (G. sepium). Acacia spp had moderate CP values (g/kg DM) of 144 (A. nilotica), to high CP in A. tortilis (188) and A. polyacantha (194) comparable to G. sepium. The forages had relatively lower fiber compositions. A. nilotica had (p<0.05) lowest NDF, ADF and ADL (182, 68 and 44) compared to P. thonningii (619, 196 and 130) g/kg DM, respectively. Except G. sepium, all fodder species had detectable high phenolic and tannin contents greater than 5% DM, an upper beneficial level in animal feeding and nutrition. Mean total phenolics (TP), total tannins (TT) and condensed tannins (CT) (or proanthocyanidins) for fodder species tested were 139, 113 and 43 mg/g DM, respectively. F. villosa had (p<0.05) lowest TP and TT of 65 and 56 mg/g DM, respectively, compared to A. nilotica (237 and 236 mg/g DM, respectively). The CT varied (p<0.05) from 6 (F. villosa) to 74 mg/g DM (Dichrostachys sp). In vitro organic matter (OM) degradability (OMD) differed (p<0.05) between fodder species. G. sepium had (p<0.05) high degradability potential compared to A. polyacantha that had (p<0.05) the lowest OMD values. Forage degradability ranked: G. sepium>A. nilotica>P. thonningi>F. villosa>Dichrostachys sp>A. tortilis>A. polyacantha. Addition of PEG resulted to (p<0.05) improvement in in vitro OM digestibility (IVD). Increase in IVD was mainly due to binding action of PEG on tannins; and represents potential nutritive values previously depressed by tannins anti-nutritive activity. Browse fodder has potential as sources of ruminal nitrogen especially for ruminants consuming low quality roughages due to high protein, lower fiber compositions and high potential digestibility. However, utilization of browse supplements in ruminants is hampered by high phenolic and tannin contents. Deactivation of tannin anti-nutritive activity, possibly by feeding tanniniferous browse with other readily available nitrogen sources to dilute tannin anti-nutritive activity could improve utilization of browse fodder supplements. Further studies are needed to assess browse fodder palatability and intake, and their effect on growth performance in ruminants.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.655-661
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• 2011

Two experiments were conducted to investigate the effect of dietary supplementation of Bacillus, Saccharomyces and lactic acid bacteria (LAB) on performance and nutrient digestibility in grower and finisher pigs. In Exp. 1, 80 pigs (32 females and 48 males), $28.7{\pm}0.9\;kg$ body weight (BW), were randomly divided into 4 treatment groups balanced for sex and weight (5 pigs per pen, 4 pens per treatment). They were fed one of four diets: a basal grower (20-50 kg BW) and finisher (>50 kg BW) diet without any addition of probiotic or antibiotic (diet C), the basal diet supplemented with Bacillus subtilis H4 (diet B), diet B supplemented with Saccharomyces boulardi Sb (diet BS) and diet BS supplemented with a LAB complex (diet BSL). The LAB complex consisted of Enterococcus faecium 6H2, Lactobacillus acidophilus C3, Pediococcus pentosaceus D7, and Lactobacillus fermentum NC1. In Exp. 2, 16 male pigs, $29.2{\pm}0.8\;kg$ BW, were kept in individual pens and divided into 4 groups (4 pigs in each group). All 4 groups were given exactly the same growing-period diets (diet C, B, BS and BSL) as in Exp 1. The total faeces and urine were collected during 5 days (day 20-24) to determine nitrogen retention and total tract digestibility. In the growing period, average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR) were not affected by diet B and BS (p>0.05), but ADG increased (+5.9%) (p<0.05) and FCR improved (+5.9%) (p<0.05) on diet BSL compared with the control, although ADFI was not different (p>0.05). Digestibility of crude protein and organic matter was higher (p<0.05) in diet BSL and digestibility of crude fibre was higher (p<0.05) in diet BS and BSL than in diet C. Nitrogen retention was not affected by diet (p>0.05). The faecal LAB counts were increased in grower pigs fed diet BSL (p<0.05) and faecal E. coli counts were decreased in pigs fed diets BS and BSL (p<0.05). In the finishing period, no effects of diet were found in ADFI, ADG, FCR, nutrient digestibility, and nitrogen retention (p>0.05). Faecal LAB and E. coli counts in the finisher pigs were not affected by diet (p>0.05). In conclusion, the current study demonstrates that a mixture of bacteria and yeast has the potential to be used as a probiotic dietary supplement in grower pigs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.1
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• pp.27-32
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• 2016

Streptococcus mutans plays a virtal role in trigering dental caries establishment due to its ability to synthesize two significant factors. The two factors are organic acids and glucans. The former demineralized dental enamel and the latter mediates the attachment of bacteria to tooth surface. It is believed that demineralization of dental enamel and attachment of bacteria are the crucial events that indicate and develop dental caries. For this reason, we studied the effect of the ethanol extracts of Radix Pulsatillae on the growth and acid production of S. mutans. Ethanol extracts of the Radix Pulsatillae showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition compared to the control groups (p<0.05). The extracts inhibited S. mutans adherence to hydroxyapatite treated with saliva, and cell adherence was repressed by Radix Pulsatillae. the ethanol extract of Radix Pulsatillae showed remarkable inhibition of glucosyltransferase, which synthesizes water insoluble glucan form sucrose. Phytochemical analysis showed Radix Pulsatillae contained major components such as phenolic compounds, glycosides, steroids, terpenoid, and saponin. These results suggest that Radix Pulsatillae may have anti-cariogenic properties, which may be related with major components such as phenolic compounds, glycosides, steroids, terpenoid, and saponin.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.668-680
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• 2020

Bacillus velezensis is an important plant growth-promoting rhizobacterium with immense potential in agriculture development. In the present study, Bacillus velezensis Lle-9 was isolated from the bulbs of Lilium leucanthum. The isolated strain showed antifungal activities against plant pathogens like Botryosphaeria dothidea, Fusarium oxysporum, Botrytis cinerea and Fusarium fujikuroi. The highest percentage of growth inhibition i.e., 68.56±2.35% was observed against Fusarium oxysporum followed by 63.12 ± 2.83%, 61.67 ± 3.39% and 55.82 ± 2.76% against Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi, respectively. The ethyl acetate fraction revealed a number of bioactive compounds and several were identified as antimicrobial agents such as diketopiperazines, cyclo-peptides, linear peptides, latrunculin A, 5α-hydroxy-6-ketocholesterol, (R)-S-lactoylglutathione, triamterene, rubiadin, moxifloxacin, 9-hydroxy-5Z,7E,11Z,14Z-eicosatetraenoic acid, D-erythro-C18-Sphingosine, citrinin, and 2-arachidonoyllysophosphatidylcholine. The presence of these antimicrobial compounds in the bacterial culture might have contributed to the antifungal activities of the isolated B. velezensis Lle-9. The strain showed plant growth-promoting traits such as production of organic acids, ACC deaminase, indole-3-acetic acid (IAA), siderophores, and nitrogen fixation and phosphate solubilization. IAA production was accelerated with application of exogenous tryptophan concentrations in the medium. Further, the lily plants upon inoculation with Lle-9 exhibited improved vegetative growth, more flowering shoots and longer roots than control plants under greenhouse condition. The isolated B. velezensis strain Lle-9 possessed broad-spectrum antifungal activities and multiple plant growth-promoting traits and thus may play an important role in promoting sustainable agriculture. This strain could be developed and applied in field experiments in order to promote plant growth and control disease pathogens.

• Research in Plant Disease
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• v.30 no.2
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• pp.148-156
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• 2024

Ralstonia pseudosolanacearum, a plant pathogenic bacterium that can survive for a long time in soil and water, causes lethal wilt in the Solanaceae family. Sigma S is a part of the RNA polymerase complex, which regulates gene expression during bacterial stress response or stationary phase. In this study, we investigated the role of sigma S in R. pseudosolanacearum under stress conditions using a rpoS-defective mutant strain of R. pseudosolanacearum and its wild-type strain. The phenotypes of rpoS-defective mutant were complemented by introducing the original rpoS gene. There were no differences observed in bacterial growth rate and exopolysaccharide production between the wild-type strain and the rpoS mutant. However, the wild-type strain responded more sensitively to nutrient deficiency compared to the mutant strain. Under the nutrient deficiency, the rpoS mutant maintained a high bacterial viability for a longer period, while the viability of the wild-type strain declined rapidly. Furthermore, a significant difference in pH was observed between the culture supernatant of the wild-type strain and the mutant strain. The pH of the culture supernatant for the wild-type strain decreased rapidly during bacterial growth, leading to medium acidification. The rapid decline in the wild-type strain's viability may be associated with medium acidification and bacterial sensitivity to acidity during transition to the stationary phase. Interestingly, the rpoS mutant strain cannot utilize acetic acid, D-alanine, D-trehalose, and L-histidine. These results suggest that sigma S of R. pseudosolanacearum regulates the production or utilization of organic acids and controls cell death during stationary phase under nutrient deficiency.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.83-89
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• 1981

Several kinds of organic acids, alcohols, aromatic compounds and sugars as carbon sources were tested in order to produce the cell mass of Rhizopus oryzae which is used in part of food processing or organic acid fermentation. Sodium acetate among them was good enough for carbon source as well as glucose under the concentration of one percent. All nitrogenous substances tested such as ammonium, nitrate or organic nitrogen compounds were well used by this strain of Rhizopus oryzae as nitrogen source. Ammonium sulfate among inorganic nitrogen compounds was most utilized as a nitrogen source in glucose or acetate medium. This strain did not require any growth factors such as yeast extract. The following composition of medium was therefore determined in order to produce the cell mass of Rhizopus oryzae: Na-acetate 1 %, (NH$_4$)$_2$SO$_4$ 0.2%, $K_2$HPO$_4$ 0.05%, MgSO$_4$.7$H_2O$ 0.01%, NaCl 0.01% (PH 5.5). The cell wall of mycelium grown in above medium was lysed optimally at pH 6.5 and 5$0^{\circ}C$ by the action of Strepzyme 115-5. On producing protoplast from mycelium by enzymatic action, almost all of the mycelium was damaged after 4hrs of treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.247-262
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• 1979

Majority of reclaimable soils in hillside lands in Korea are red yellow soils, with exception in Jeju island, where most of reclaimable hillside lands are composed of volcanic ash soils. Songjeong, Yesan and Samgag series are the major soil series of red yellow soils which are available for the reclamation. When observed in the fields, they are distinguished as reddish brown clay loam, red yellow sand loam and yellowish brown sand loam. They have moderately good physical properties but their chemical properties are generally poor for crop cultivations. The chemical properties of red yellow soils, as compared to long time cultivated (matured) soils, are characterized by very low pH, high in exchangeable Al content and phosphorus fixation capacity. Also extraodinary low available phosphorus and organic matter contents are generally observed. On the other, the chemical properties of volcanic ash soils are characterized by high armophous Fe and Al hydroxides and organic matter contents, which are the causative factors for the extremely high phosphorus fixation capacity of the soils. The phosphorus fixation capacity of volcanic acid soils are as high as 5-10 times of that of red yellow soils. Poor growth of crops on newly reclaimed red yellow soils are mainly caused by very low available P and pH and high exchangeable Al. Relatively high P fixation capacity renders the failure of effective use of applied P when the amount of application is not sufficient. Applications of lime to remove the exchangeable Al and relatively large quantity of P to lower the P fixation capacity and to increase the available P are the major recommendations for the increased crop production on red yellow hillside soils. Generally recommendable amounts of lime and P to meet the aforementioned requirements, are 200-250kg/10a of lime and $30-35kg\;P_2O_5/10a$. Over doses of lime. frequently induces the K, B, arid Zn deficiencies and lowers the uptake of P. In volcanic ash soils, it is difficult to alter the exchangeable Al and the P fixation capacity by liming and P application. This may be due to the peculiarity of volcanic ash soil in chemical properties. Because of this feature, the amelioration of volcanic ash soils is not as easy as in the case of red yellow soils. Application of P as high as $100kg\;P_2O_5/10a$ is needed to bring forth the significant yield response in barley. Combined applications of appropriate levels of P, lime, and organic matter, accompanied by deep plowing, results in around doubling of the yields of various crops on newly reclaimed red yellow soils.

• Clean Technology
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• v.27 no.2
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• pp.132-138
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• 2021

Research is being conducted on graphene to provide graphene having both excellent physical as well as electrical properties in addition to unique physical properties. In this study, Hummer's method, which is a representative method for chemical exfoliation, was applied in order to investigate the possibility of the mass production of high-quality graphene oxide. Three types of graphite (graphite, crystalline graphite, and expanded graphite) were used in the preparation of graphene oxide with variations in the amount of potassium permanganate added, reaction temperature, and reaction time. Then a Fourier transform infrared spectroscopy (FT-IR), a Raman spectrometer, and a transmission electron microscope (TEM) were used to measure the quality of the prepared graphene oxide. Of the three types of graphite used in this experiment, crystalline graphite showed the highest quality. The prepared graphene oxide was then purified with an organic solvent, and an analysis conducted using energy dispersive X-ray spectroscopy (EDS). From the results of the residual values, we were able to confirm that both acid wastewater and wastewater were best purified using cyclohexane. The method for manufacturing graphene oxide as well as the method of purification using organic solvents that are presented in this study are expected to have less of an environmental impact, making them environmentally friendly. This makes them suitable for use in various industrial fields such as the film industry and for heat dissipation and as coating agents.

• Animal Bioscience
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• v.35 no.6
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• pp.916-926
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• 2022

Objective: This study was conducted to evaluate the effects of medium chain triglycerides (MCT) with organic acids (OA) on growth performance, fecal score, blood profiles, intestinal morphology, and nutrient digestibility in weaning pigs. Methods: A total of 120 weaning pigs ([Yorkshire×Landrace]×Duroc) with an average body weight (BW) of 8.00±0.87 kg were assigned in five treatments considering sex and initial BW in 3 replications with 8 pigs per pen in a randomized complete block design. The experimental diets included a corn-soybean meal based basal diet with or without 0.1% or 0.2% MCT and 0.1% OA. The pigs were fed the diets for 5 weeks (phase 1, 0 to 2 weeks; phase 2, 3 to 5 weeks). A total of 15 barrows with an average BW of 12.48±0.37 kg were used to evaluate the nutrient digestibility by total collection method. The BW and feed intake were measured at the end of each phase. Blood samples and small intestine samples were collected at the end of each phase, too. Results: Supplementing 0.1% MCT with 0.1% OA showed greater BW for week 5 and average daily gain (ADG) for overall period than control diet. Supplementing 0.1% MCT increased (p<0.05) ADG and improved (p<0.05) gain:feed ratio for phase 1. Dietary MCT and OA did not affect the fecal score and blood concentration of cortisol, immunoglobulin G, tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, and IL-10 in weaning pigs. Pigs fed the diets with 0.1% MCT had greater (p<0.05) villus height of duodenum and ileum for phase 1. Also, pigs fed the diet with 0.1% OA showed greater (p<0.05) villus height and villus height to crypt depth ratio of duodenum for phase 2. There was no significant difference in nutrient digestibility and nitrogen retention of pigs. Conclusion: Addition of 0.1% MCT with 0.1% OA in weaning pig's diet improved growth performance partly by enhancing intestinal morphology in weaning pigs.