Vol. 17 No. 5 (2019)

In this study, A. pleuropneumoniae, P. multocidaandS. suisstrains, previously used to produce polyvalent inactivated vaccine with aluminium hydroxide adjuvant against pneumonia disease caused by these bacteriain swine, were used with fermentation and oil emulsion adjuvant - IMS 1313. We have produced the polyvalent inactivated vaccine with oil emulsion adjuvant with higher potency and immunity to prevent pneumonia disease in swine from4 weeks of age.Thequality testshowed that the safety of vaccine was 100% in mice and piglets. By the challenge testing, the protection rate of vaccine on experimental pigs was more than 80.0%. The serological test proved that vaccine achieved a high and prolonged antibody titre when tested on piglets. After 4 months of vaccination, the vaccine attained an average antibody titre greater than 4 log2 with A. pleuropneumoniaeserotype 2, 5a, and 5b; and P. multocidaserotype A, D and S. suistype 2.The produced Polyvalent Inactivated Vaccine with Oil Emulsion Adjuvant is proved to be of high quality according to Vietnam’s standards.

This study was carried out to examine the effects of different stimulation methods on spawning of the black apple snails, Pila polita. The experiments were arranged in 1 m3 tanks (1×1×1 m) at density of 15 pairs of broodstock snail/tankwhere water column at the beginning was 40 cm high. Experiment 1was done with 4 different water exchanging regimes: 1) Discard 25% water (D25); 2) Discard 50% water (D50); 3) Discard 75% water (D75) and 4) Discard 100% water (D100). Results showed that the highest spawning rate occurred at D75 (60.6%), following by the D50 (58.3%) and these were significantly different from D25 or D100 (P <0.05). The broodstock snails at D75 released highest egg clutches and reproductive efficiency (9.08 clutch/m2; 3.03 clutch/day/m2) and statistically significant different from D25 and D100 (P<0.05). Experiment 2 was implemented in the same condition as the early one (started with 40 cm of water level in the experiemental tanks) but with 4 different spawning stimulation methods: 1) Adding 25% water (A25); 2) Adding 50% water (A50); 3) Adding 75% water (A75) and 4) Addiing 100% water (A100). The spawning rate in A50 (82.2%) was significantly higher (P <0.05) than that inA25 (66.7%) and A100 (64.4%). The numbers of released egg clutches and reproductive efficiency of the snails in A50 (12.3 clutch/m2; 4.11 clutch/day/m2) were significantly higher than those (P<0.05) from A25 (10.1 clutch/ m2; 3.33 clutch/day/m2) or A100 (9.7 clutch/m2; 3.22 clutch/day/m2). The research results show that the spawning stimulation by renewing 75% of water or adding 50% of water volume gave the higher reproductive efficiency than other methods.

The aim of this study was to evaluate the effectiveness of three fecal examination techniques: sugar floatation (SG: 1.27), saturated salt flotation (SG: 1.18) and formol-ether concentration, to determine the parasite eggs and oocysts in dogs. Examination of 270 dog fecal samples in some areas of Vinh Phuc, Thai Binh, Phu Tho and Thai Nguyen provinces, the result showed that the overall prevalence of gastrointestinal parasites in dogs is 75.18%. Twelve kinds of parasites were detected, consisting of one intestinal fluke (Heterophyids), six roundworms (Toxocara canis, Toxascaris leonina, Trichuris vulpis, Capillariasp., Strongyloides canisand hookworm), four tapeworms (Dipyllidium caninum, Diphyllobothrium latum, Spirometrasp., and Taeniasp.) and one coccidia (Cystoisosporasp.). Hookworm (58.81%) is the most prevalent in dogs, following by and Toxocara canis(31.11%). Sugar floatation technique showed the most effective for detection of roundworm eggs and coccidia oocysts, following by saturated salt floatation technique. Formol-Ether concentration one has more effective for detection of tapeworm egss and larva-containing roundworm eggs compared to the other techniques, but it cannot detect coccidia oocysts. In conclusions, the result of study showed that the choice of which fecal examination technique depending on the purpose of each study.

Litter size of pigs is an important economic trait, but its heritability is relatively low,at approximately 0.1. In addition, litter size trait can only be measured on female pigs at mature age. Therefore, genetic improvement by phenotypic selection is less effective, and at slow rate. In previous literature, it is found that ESR and PRLR genes are two QTLswith large effects on litter size in pigs. Of the two alleles A and B at ESR locus, allele B shows a positive effect on the litter size trait,while of the two alleles A and B at PRLR locus, allele A is benefical to the trait. Landrace and Yorkshire, which are imported, are two major breeds in Vietnam. The current study aimed to evaluate genetic structures of ESR and PRLR genes in two pig populations of Landrace and Yorkshire reared at the Dabaco nuclear breeding pig company, and thus examine the effects of ESR and PRLR genes on reproduction traits of the two pig populations. It was found that all three genotypes,AA, AB and BB at ESR and PRLR loci,were present in both the populations of Landrace and Yorkshire pigs. At ESR locus, allele frequency of B in the Landrace population (0.184) was lower than in the Yorkshire population (0.413). The frequency of homozygous genotype BB was 0.041 for the Landrace population and 0.655 for the Yorkshire population. At PRLR locus, allele frequencies of A and B were quite similar for the two populations. Allele frequency of A was 0.483 for Landrance and 0.516 for Yorkshire. Allele frequency of B was 0.517 for Landrance and 0.484 for Yorkshire.

The Jaccard index is a statistic used for comparing the similarity and diversity of sample sets. In this paper, we proposeda new similarity measure for picture fuzzy sets based on the Jaccard index.We then comparedthe proposed similarity measure with some existing similarity measures and showedthat the new similarity measure overcomes the restrictions of the existing similarity measures. Finally, we used this new similarity measure forthe data clustering problem.

This article presented the results ofexperimental research on the effects of some technological parameters on drying regime (drying time and specific energy consumption) for cassava chooped into 3-5 cm in size on continuous cross-flow particle dryer. Throung an empirical study, the drying temperature was distributed in the range 75-95C and the drying velocity between 1.65-2.25 m/s. The use of experimental planning with three inputs (the drying temperature, the velocity of drying flow and the moisture content of the input material) to affect two target functions, viz.: minimum drying time and lowest specific energy consumption, revealed optimum technological parameters, as well as: drying temperature (87.52C),velocity of drying agent flow (1.9 m/s), moisture content of input material (58.68%) for the objective function. The drying time was 47.8805 hours and the specific energy consumption was1.18475 kWh/kgH2O.

Medicinal plants are starting to be cultivated in the Central Highlands. In order to develop value chains of medicinal plants in the Central Highlands, it is necessary to investigate and assess the current situation. The PRA, key person interview and expert methods were used to collect data. Two districts in each province and 2 communes in each district were surveyed. The results showed that in order to develop medicinal herbs in a sustainable manner, it is necessary to conduct researches on varieties, planting area planning, appropriate farming techniques, preprocessing, processing and preservation of commodity products and adopt policies to encourage farmers and enterprises to join the medicinal value chain. The indigenous medicinal plants thantcan be developed in the Central Highlands include Vietnamese Ginseng (Panax vietnamensisHa et Grushv), Dang sam (Codonopsis javanica(Blume) Hook. f. & Thoms), Ngu vi tu (Schisandra sphenanthera) and Giao co lam (Gynostemma pentaphyllum). In addition, it is recommended to establish areas for the temperate medicinal herbs such as artichoke (Cynara scolymusL.) and (Angelica acutiloa Kitagawa), at the same time, expanding the area for intercropping like turmeric (Curcuma longaL.) amd Ginger (Zingiber officinaleRosc). In the central area of the Central Highlands, it is necessary to develop valuable commodity crops such as Crinum latifoliumL. and Ocimum gratissimumL. and testting new medicinal plants such as Polyscias fruticosaHarms) and Plukenetia volubilisL.

The study aims at analyzing the situation to recommend measures to improve disease risk management in shrimp farming in Nam Dinh province. The study was conducted in three coastal districts, including Giao Thuy, Hai Hau and Nghia Hung. The data was collected through surveys with 120 shrimp farming households and note taking records in 910 shrimp pondsto analyze the disease’s likelihood, damages and households’ risk management strategies. In Nam Dinh, within 2010 and 2016, the shrimp farming area reduced from 3.632 to 2.834 hectares, corresponding to 59.52 to 45.30% of the total aquaculture area in brackish water. Over 80% of total shrimp pondssuffered loss fromdiseaseswithin 2015 and 2016. The disease risk managementcoastal areas could be improvedthroughvarious measures, including efficiency improvement in the state management in aquacultureareaplanning, infrastructuresynchronization, capacity building for the shrimp farmers,quality controlof aquacultureinputs, financial market development, agricultural insurance, promotion of the production-consumptionlinkage, and formation of value chain for the shrimp productin coming years.

Linkages in agribusiness in Vietnam are very limited due to many reasons, one of which is the lack of relevant scientific foundations. The purpose of this study is to systematize the theoretical and practical basis of linkage between farmhouseholds and businesses in agribusiness. The research methodology is mainly to gather, select and evaluate secondary information to systematize theory and practical lessons. The research results include: (i) Systematize a number of theories on linkage between farmhouseholds and businesses in agribusinesssuch as concept, classification, mechanism, principle, content, influence factor; (ii) Summarizing experiences of 4 countries,8 provinces of Vietnam and draw 6 lessons for successful linkage which is formal mechanism, direct, voluntary, diversity,supportfrom enterprises , material security for farmers and the role of the state; (iii) Proposing some research directions with Vietnam such as improvingthe theory, reviewing experience, state management, reasons for failure, and strengthening the capacity of farmer households and enterprises.

The Northwest is a regionwith important strategic position in terms of national security, economic development,and environmental protection. In recent years, various agricultural policies have been implemented in the region to improveinfrastructure, productionefficiency, and marketaccessibility. However, the poverty rate is currently the highest among seven economic regions, being three-fold ofthe countryaverage. The information collected from government reports, sixNorthwestern provinces, and surveys showedthat agricultural policies brought significant improvement in agricultural production such as crop yields, forest cover, GDPcontribution, household’s income and poverty reduction. Most ofpolicies havefocusedon inputsubsidy, but less attention to marketing, agricultural extension, and forest-based livelihood activities, resulting in underexploited region’s advantages.