Published: 2018-12-31

Application of SARIMA model to forecasting the natural rubber price in the world market

Nhien T. Pham
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.1.06.2018
Abstract | PDF (3.3M)

Abstract

This study was conducted to develop a forecasting model to predict theprice natural rubber in the world market by using the Seasonal Autore-gressive Integrated Moving Average (SARIMA). The dataset for modeldevelopment was collected from series data of average monthly clos-ing average prices in the natural rubber - Ribbed Smoked Sheet No.3(RSS3) on the Tokyo Commodity Exchange (TOCOM) for the periodof January 2007 - September 2018. The RSS3 price on the TOCOMprovided the reference price for natural rubber in the world market.It resulted SARIMA(2,1,2)(1,1,1)12model was selected as the best-fit model. The model achieved 0.000 for Probability value (P-value);8.86 for Akaike Information Criterion (AIC) and 9.01 for Schwarz In-formation Criterion (SIC); 6.68% for Mean Absolute Percentage Error(MAPE) and 21.43 for Root Mean Square Error (RMSE). This modelwas used to forecast the world’s natural rubber price during Octo-ber 2018 - December 2020. This study may be helpful to the farmers,traders, and the governments of the world’s important natural rubberproducing countries to plan policies to reduce natural rubber produc-tion costs and stabilize the natural rubber price in the future, such asby setting suitable areas for natural rubber plantation in each country,and defining appropriate and sustainable alternative crop areas in eachcountry.

Detecting toxin genes of Clostridium perfringens isolated from diarrhea piglets using multiplex PCR

Phat X. Dinh, My N. H. Dung, Thi H. Phuong, Xuan L. T. Quynh, & Kim T. Thoai
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.4.06.2018
Abstract | PDF (260.1K)

Abstract

Clostridium perfringens is currently classified into five types (A, B, C, D, E) based on the different toxins produced. Type A and C are known as the causative agent of enteritis and enterotoxemia in newborn and young piglets with severe intestinal lesions including edema, hemorrhage and necrosis. A multiplex PCR (mPCR) was developed in order to quickly and early determine the presence of genotypes of C. perfringens based on their genes of cpa, cpb, cpb2 and cpe encoding alpha toxin, beta toxin, beta2 toxin and enterotoxin with predicted products of 324 bp, 196 bp, 107 bp and 257 bp respectively. The detection limit of the mPCR assay was 1 × 103 copies/reaction for each gene. Sequencing of mPCR products performed with clinical samples collected from C. perfringens suspected pigs showed that the mPCR test functioned specifically. In conclusion, the developed mPCR test successfully detected the presence of genes cpa, cpb, cpb2 and cpe in the examined samples. Analysis of the bacteria isolated from field samples of diarrheal piglets collected in this study indicated that C. perfringens carrying gene cpa counted for 96.66% and 3.33% was identified as C. perfringens carrying genes cpa and cpb concurrently. Gene cpe was not found in this study, while gene cpb2 was detected coincidently in 73.33% of the samples with cpa gene. The results indicate that the prevalence of these four toxin genes is cpa, cpb2, cpb and cpe in decending order.

Species composition and catch of sharks, rays and skates in Ba Ria - Vung Tau and Binh Thuan provinces of Vietnam

Manh Q. Bui, Toan X. Nguyen, Anh H. T. Le, & Ali Ahmad
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.5.06.2018
Abstract | PDF (260.1K)

Abstract

Research on 2,626 individuals of sharks, rays and skates in total of 123 fishing boats were sampled during 2015 to 2016 in Ba Ria - Vung Tau and Binh Thuan provinces. The results identified 77 species of sharks, rays and skates belong to 22 families and 10 orders in Ba Ria - Vung Tau and Binh Thuan provinces. Of these, 57 species were recorded in Ba Ria - Vung Tau and 48 species in Binh Thuan. The families were found in the highest number of species such as Carcharhinidae family with 9 species, Dasyatidae family with 19 species and Rajidae family with 5 species. The total catch of sharks, rays and skates was 23,599 tons in Ba Ria - Vung Tau and was 24,355 tons in Binh Thuan. Sharks, rays and skates ratio made up from 0.2% to 0.5% in total catch landing from landing sites. Total length of sharks ranges from 21.0 cm to 366.0 cm, disc length of rays fluctuates from 11.0 cm to 248.0 cm and skates have a range from 0.7 cm to 152.0 cm in disc length.

Efficacy of organic acids as an alternative to antibiotic growth promoters in weaned pigs

Tung M. Che, Nhan T. M. Nguyen, Hai T. Nguyen, Tai T. Le, & A. Peron
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.2.06.2018
Abstract | PDF (3.3M)

Abstract

The objective of the experiment was to compare effects of dietarysupplementation of organic acids (ProHacid Advance, PRO) andantibiotics on growth performance, diarrhea incidence, frequencyof antibiotic treatment, andE. colishedding in weaned pigs.A total of 224 crossbred weaned pigs [(Yorkshire x Landrace)x Duroc; 29 days old)] were allotted to 1 of 4 treatments with7 replicate pens of 8 pigs each according to sex, litter originand weight in an RCBD. The 4 dietary treatments included(1) basal diet + 50 mg/kg neomycin and 10 mg/kg enramycin(positive control, PC), (2) basal diet without antibiotics (negativecontrol, NC), (3) As 2 + 0.25% PRO, and (4) As 2 + 0.5%PRO. Over a 4-week study, the results showed that there wereno differences in the average daily gain and average daily feedintake of pigs among the 4 treatments (P= 0.328). However,pigs fed the PC diet (1.642) and 0.25% PRO-supplemented diet(1.641) had a lower feed to gain ratio(P< 0.05) than those fedthe NC diet (1.808). The diarrhea incidence of pigs fed the 0.25%PRO-supplemented diet(7.36%) was lower(P< 0.01) than thatof pigs fed the PC diet(11.61%), NC diet (16.70%), and 0.5%PRO-supplemented diet(10.08%). The frequency of antibiotictreatment of pigs consuming the 0.25% PRO-supplemented diet(4.67%) was lower(P< 0.01) than that of pigs consuming the PCdiet(7.33%), NC diet (9.53%) and 0.5% PRO-supplemented diet(7.65%). No differences were found in the number of fecalE. coliamong the 4 treatments. In brief, 0.25% PRO added to a nurserypig diet would be considered a potential alternative to the useof antibiotics in feed, but further research on this aspect is needed.

Field assessment of the efficacy of M.B., LIBDV and Winterfield 2512 strain vaccines against infectious bursal disease in chickens

Anh T. Quach, Hien T. Le, Ho M. Nguyen, & Anh T. T. Le
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.3.06.2018
Abstract | PDF (260.1K)

Abstract

Live virus vaccines are very important parts of the prevention of Infectious Bursal Disease (IBD) in chickens. However, the successful IBD vaccination depends on IBD field pressure, vaccination technique, the immune status of the chicken, and especially IBDV strains used in the vaccines which are able to break through a higher level of maternal-derived antibodies (MDA). The objective of this field study was to compare the efficacy of a new vaccine based on M.B. strain to other commercial vaccines (LIBDV and winterfiled 2512) in terms of speed of antibody immune response and interference to Newcastle Disease (ND) vaccination. Six houses of broilers, each with 15,000 to 16,000 chickens, were divided into two groups: (1) vaccinated with M.B. strain (group A) and (2) vaccinated with LIBDV or 2512 strains (group B). Blood samples were collected prior to the 1st IBD vaccination, and at 21, 28 and 35 days of age for IBD and ND antibodies. Comparison of lesion scores and uniformity of the bursa of Fabricius (BF) at 28 and 35 days of age was carried out. Results showed that both groups had good immune responses, but group A showed significantly higher IBD antibody titers at 28 and 35 days of age. Antibody titers for ND and histopathological lesion scores of the BF were not significantly different between the 2 groups. The BF in group A was more uniform and had fewer lesions when compared with that in group B. In conclusion, the IBD vaccine with an M.B. strain can provide better immunological efficacy than LIBDV and 2512 strains.

Concentrations of heavy metals in water from the Southern coast of Vietnam

Tu P. C. Nguyen, Ha . N. Nguyen, Tri N. Nguyen, & Dong V. Nguyen
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.6.06.2018
Abstract | PDF (3.3M)

Abstract

Concentrations of heavy metals (As, Cd, Pb and Hg) in water collectedfrom seven coastal provinces between December 2012 and December 2015were evaluated. The average total concentrations (μg/L) of As, Cd, Pband Hg in water ranged from 2.90 to 6.38, < 0.039 to 0.322, 4.26 to 10.5and < 0.01 to 0.118, respectively. The average concentrations (μg/L) ofAs, Pb and Hg in suspended particulate matters (SPM) ranged from0.392 to 7.32, 0.365 to 18.7 and < 0.01 to 0.038, respectively; whereas,Cd concentrations were not detected in most of SPM samples. Therewere positive linear relationships between concentrations of heavy metalsin water and SPM, except for Cd. The results showed that the concen-trations of metals analyzed in water remained below quality guidelinesfor the protection of aquatic life recommended by the international andVietnamese organizations. However, As levels in 2/103 and 5/103 of watersamples exceeded the QCVN 10:2015/BTNMT for maximum permittedlevel using for aquaculture and aquatic life protection (20μg/L) and theCanadian water quality guidelines for the protection of aquatic life (12.5μg/L), respectively.

Investigation of fermentation conditions for Candida bombicola ACTT22214 from molasses and soybean oil for sophorolipid production

Tho P. Le, Hue T. B. Nguyen, Hiep M. Dinh, & Huong T. T. Le
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.7.06.2018
Abstract | PDF (260.1K)

Abstract

Sophorolipid (SL) is a biosurfactant belonging to the glycolipids group and was produced by harmless Candida bombicola ACTT22214 and has been widely used in many fields in our life. In order to search for appropriate condition for C. bombicola fermentation producing SL with high efficiency, this study focused on the investigation of the soy oil concentration, molasses concentration, fermentation time, pH and temperature. SL products were tested for antimicrobial activity, antioxidant, emulsifier, foaming ability. The highest content of SL was 43.27 ± 0.30 g/L under conditions of: soybean oil content 5%, molasses content 150 g/L, fermentation time 7 days, pH = 5, 280C fermentation temperature. The antibacterial activity of SL was good: the highest resistance to Candida albicans (16.33 ± 1.15 mm), good resistance to Bacillus spizizenii (13.67 ± 0.58 mm), resistance to Staphylococcus aureus (12.67 ± 1.15 mm), relatively weak resistance to Pseudomonas aeruginosa (11.33 ± 0.58 mm) and Escherichia coli (9.67 ± 0.58 mm). The antioxidant capacity of SL was quite high with an IC50 value of 6.024 mg/mL. The emulsifying capacity of SL was equivalent to the emulsification of the tween 20 at a concentration of 5 – 10 mg/mL. SL had the ability to foam evenly from concentrations of 5 to 20 mg/mL but not higher than the corresponding concentrations of tween 20, SL was smooth, even, stable longer than tween 20.

Factors affecting betacyanin stability in juice of LD5 Red-fleshed dragon fruit (Hylocereus polyrhizus)

Ngan N. T. Trinh, Anh H. T. Nguyen, Mai T. P. Phung, Trang T. M. Nguyen, Thuy T. P. Nguyen, & Huan T. Phan
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.9.06.2018
Abstract | PDF (3.3M)

Abstract

n Binh Thuan province (Vietnam), the red-fleshed dragon fruit(Hylocereus polyrhizus), concretely LD5 variety majorly grows andcontains a large amount of betacyanin, a natural colourant thatpotentially applied to many products in the food industry. In thisstudy, the processing factors possibly influencing the betacyaninstability in the red-fleshed dragon fruit juice were in turn investigated.The heating treatment included 2 factors: temperature (65, 75 and850C) and heating time (10, 20 and 30 minutes); while the pH valuesranged between 3.0 to 7.0 and the ascorbic acid addition varied inconcentrations (0.1, 0.2, 0.3, 0.4 and 0.5% w/w). The processed fruitjuice was stored in different packaging materials (plastic and glass)with and without light exposure for 5 weeks to monitor the retainedbetacyanin. The results showed that the betacyanin was remained withthe highest proportion (0.84±0.02) at 0.3% ascorbic acid addition, pH4.0 and heat treatment at 650C for 10 minutes. In storage without lightexposure, both plastic and glass packaging materials kept efficientlybetacyanin in fruit juice. However, the glass material represented bet-ter efficiency in the betacyanin remaining than the plastic material did.

Total phenolic content and antioxidant activity of sesame cake aqueous extracts

Tuyen C. Kha, Yen T. X. Nguyen, Stathopoulos Costas, Chockchaisawasdee Suwimol, & Phuong L. Nguyen
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.10.06.2018
Abstract | PDF (3.3M)

Abstract

The objective of this study was to investigate the efficiency ofphenolic extraction and antioxidant activity from sesame cakeusing water extraction method and to evaluate the possibility ofemploying microwave irradiation to improve the extraction yield.The result showed that extraction temperature had major influ-ence on total phenolic content and antioxidant activities of theextracts, whereas extraction time was found to be insignificant.The optimum extraction condition recommended were 900C for30 min in this research. Furthermore, microwave pre-treatmentat 120 s could have significantly positive influence on the overallextraction yield, especially the total phenolics and antioxidantsbased on FRAP assay. Therefore, the obtained results suggestthat sesame aqueous extracts could be a source of antioxidantswith more feasible applications in food as well as other industries.

Effects of film coating materials on the quality of postharvest ‘Sanh’ orange fruits (Citrus nobilis var. Typica) during storage

Thach A. Nguyen, & Ngan T. Nguyen
Electronic version: 31 Dec 2018 | DOI: 10.52997/jad.8.06.2018
Abstract | PDF (3.3M)

Abstract

Postharvest orange fruit coating is an effective method toreplace natural waxes which lost during washing and handling.The coatings can reduce water loss and impart gloss to the fruit.In this study, the oranges were stored at room temperature(30±20C) with five coating materials: polyethylene (PE), andpolypropylene (PP) bags, polyvinyl chloride (PVC) film, CitraShine preservatives and 1% chitosan and the control were used.Some typical nutritional values and weight loss were determinedduring storage time. Research results show that PVC coated‘Sanh’ oranges could be prolonged their shelf life up to 25 dayswith low damage ratios (7.10%, lower than other bags) whichwere acceptable in appearance with green peel color. Ascorbicacid content still maintained at a high level (12.32 mg/100 g),and weight loss relatively low (13.91%). Moreover, pH (3.77) andTSS (9.70) values did not significantly change during storagetime.