Researching and breeding cassava varieties with high starch yield, resistance to major pests and diseases, and suitability to the production conditions of Phu Yen province and ecological regions is important and urgent. The objectives of this study were to select and create cassava varieties with high starch yield (at least 10% higher than controls KM419 and KM94), resistance to major pests and diseases, grade 1 - 2 disease scores for cassava mosaic disease (CMD), and cassava witches broom disease (CWBD). The research method was used according to Vietnam Cassava Program and International Center for Tropical Agriculture (CIAT) standards for technological process of hybrid cassava selection and breeding. The results showed that three promising cassava varieties KM568, KM539, and KM537 were identified. KM568, a hybrid of KM440 x (KM419 x KM539), yielded 54 tons/ha of fresh tubers with a starch content of 28.4% at harvest after 10 months of planting. KM539, a C39* variety, was developed from the original C39 variety from CIAT and yielded 45.9 tons/ha of fresh tubers with a starch content of 27.9%. KM537, a hybrid of (KM419 x KM539) x KM440, yielded 51.3 tons/ha of fresh tubers with a starch content of 28.5%. These three cassava varieties were resistant to CMD level 1.5 and CWBD level 1. KM568, KM539, and KM537 had 8 - 14 tubers/root, 7 - 12 tubers/root, and 7 - 12 tubers/root, respectively. Also, they all achieved the ideal new plant type shape, white root flesh, straight and compact plants, erect stems, short internodes, and less branching. Additionally, the plant height of KM568, KM539, and KM537 was 2.3 - 2.7 m, 2.7 - 3.0 m, and 2.5 - 2.9 m respectively.

Streptococcus agalactiae causing eye edema and haemorrhagic disease on red tilapia is a serious problem for the aquaculture industry. The experiment was conducted to evaluate the protective efficacy of formalin-inactivated S. agalactiae AG5 (Group B Streptococcus, GBS) vaccine on red tilapia (Oreochromis sp.) by feeding method. The experiment was arranged in a completely randomized design and fish were fed vaccine-mixed feeds with different concentrations of 104; 105; 106; 107; 108 CFU/g of feed, respectively. At 3 weeks after being fed vaccines, fish were infected with wild-type S. agalactiae AG5 strain by injecting 100 µL of medium containing a dose of LD50 = 6.87 × 103 CFU/mL into the abdomen. The effectiveness of relative percentage survival (RPS) protection was determined within 1 week after infection. Samples of dead fish were recorded with symptoms and brain samples were cultured on TSA medium and incubated at 28oC for 24 h. The colonies were examined using PCR test with F1/IMOD-specific primer pairs. The results showed that the inactivated S. agalactiae AG5 (GBS) vaccine had the highest protective effect on red tilapia of 50% at the vaccine dose of 107 CFU/g of feed. The study also showed that red tilapia had an immune response with the mean antibody titers in the vaccine treatments, ranging from 2.24 ± 0.20 to 3.59 ± 0.42 (P < 0.05).

The objective of this study was to establish and evaluate fluid therapy for treatment of diseases in dogs. The study was conducted from 12/2022 to 05/2023 in Petcare and Nong Lam University Veterinary Hospitals, Ho Chi Minh City. The methodology involved assessing dehydration levels of 5%, 7%, 10 - 12%, & 15%, calculating the required fluid volume, and evaluating effects of fluid therapy in disease cases. A total of 251 cases included 95 cases at Petcare Veterinary Hospital and 156 cases at Nong Lam University Veterinary Hospital. The results showed that the digestive disease group had the highest rate at 63.75% in cases using fluid infusion, and the infectious diseases with the rate of 19.92%. Dehydration status of cases was most commonly observed at 5 - 10%, with the 10% level accounting for the highest rate at 37.85%, followed by 7% (29.48%), 5% (21.12%), and the 12% dehydration was the lowest rate (11.16%). The effects of fluid therapy on these cases showed a recovery rate of 67.73%, a disease remission rate of 15.14%, and a death rate of 17.13%. The average treatment duration was 6.49 days for recovery cases, 7.87 days for disease remission, and 4.49 days for death cases. The highest recovery rate was 31 - 35% at 7 - 10% dehydration levels while the death rate was as high as 55.81% at 10% dehydration. The treatment effects were high by using the fluid therapy that combined ringer lactate or saline 0.9% with glucose 5%.

A total of 289 goats’ nasal swabs were collected from March to May 2023 to determine the prevalence of Pasteurella multocida in goats raised on medium-scale farms in Can Tho city. There were 143 samples representing 49.48% positive for Pasteurella multocida. Of 143 positive samples, 64 strains were selected to examine the antimicrobial susceptibility using the disk diffusion method. The results showed that those strains were still sensitive to 6/7 examined antibiotics, especially doxycycline (100%); however, they were highly resistant to ampicillin (53.13%). There were 9 phenotypes of antibiotic resistance (60.94%), with the most common patterns of ampicillin and ampicillin + amoxicillin/clavulanic acid (23.44%). By using PCR assay to detect antibiotic resistance genes, the results revealed that sulII gene was the most frequent detection (67.19%). A total of 11 resistance genotypes detected in 54 strains accounted for 84.38%, and the pattern of aadB + sulII was the most common genotype accounting for 23.44%. Therefore, the prevalence and antimicrobial susceptibility of P. multocida in goats should be controlled to protect their health and prevent spreading in husbandry environments.

The experiment was conducted from September to December, 2022 to identify the consumption of Parasesarma plicatum (Latreille, 1803) on different Rhizophora apiculata leaf litter conditions (senescent: yellowish in color, decomposition: red brown and black brown color) in a 72-h experiment with 2 crab sizes. The experiment was designed with 6 treatments and 5 replicates. Each treatment used 5 crabs which were provided with 1 type of leaves as their food. The treatments included T1: 5 bigger size crab + yellowish leaf, T2: 5 bigger size crab + reddish brown leaf, T3: 5 bigger size crab + black brown leaf, T4: 5 small crabs + yellowish leaf, T5: 5 small crabs + reddish brown leaf, and T6: 5 small crabs + black brown leaf. The results showed that the consumption of black brown leaf litter of the bigger size crab was the highest in weight and significantly different from all other treatments. It also showed that Parasesarma plicatum did not like to eat yellowish leaf litter in all treatments. In addition, there was not a statistically significant difference in leaf litter consumption among smaller crab groups. The research on the occurrence of sesarmid crabs in Can Gio mangrove forest identified two suitable habitats for sesarmid crabs according to tidal elevation, mangrove type and environmental factors. The main factors affecting the occurrence of sesarmid crabs in the habitats were the coverage of shading trees and the mangrove type (Rhizophora apiculata, Ceriops decandra, Avicennia officinalis, Avicennia marina and Lumnitzera racemosa). Thus, Parasesarma plicatum could play an important role in the detrital food web in Can Gio mangrove forest.

The study was carried out to fully utilize betel leaves for the extraction of essential oils and production of sugar-rich hydrolysates from the betel leaves residues. Essential oils in the betel leaves were extracted by hydrodistillation and the betel leaves residues were enzymatically hydrolyzed to obtain sugar-rich hydrolysates. Antioxidant and antibacterial activity of the essential oils and the hydrolysates were investigated. Chemical composition analysis of the betel leaves showed that they contained 2.23% reducing sugars, 21.10% polysaccharides, 68.01 mg/g phenolics, 6.17 mg/g flavonoids, 12.05% ash, and 1.63% tannins. Betel essential oils content was 3.14%, with the main components being eugenol (50.37%), γ-muurolene (9.65%), and α-copaene (8.22%). Betel essential oils exhibited antioxidant activity with the IC50 of 0.13 mg/mL and antibacterial capacity against three strains of bacteria, including Escherichia coli, Samonella sp. and Bacillus cereus. The enzymatic hydrolysis of betel leaves residues using Ultraflo Max with a ratio of enzyme to substrate of 5% for 96 h produced the highest amount of reducing sugars of 10.66 g/L containing 48.31% glucose. The results suggest that betel leaves residues hydrolysate can be used as carbon sources for fermentation processes to produce valueadded commodities in further investigation.