Recently, the interest towards phenol compounds has progressed. In this study, a response surface methodology (RSM) was applied to predict the optimum conditions for extraction of phenolic from red rice bran. Firstly, the effects of ethanol concentration (20–80%), added acetic acid concentration (0–20%), extraction time (0–6.5 hours), temperature (25–100oC), number of extraction cycles (1–4) and solid–solvent ratio (1/4–1/10 w/v) on total polyphenolic content (TPC) of red rice bran were found. After that, three parameters such as solvent concentration (48–68%), added acetic acid concentration (10–15%) and extraction time (120–240 min) were able to be optimized using the Box Behnken design (BBD) with a quadratic regression model built by using RSM. The experiment was designed according to 30 runs with 2 blocks; each block consists of 3 central points and 1 replicate. This design was set up for 3 factors to optimise the response in term of TPC extraction. The extracts were analyzed the TPC spectrophotometrically according to the Folin-Ciocalteu colorimetric assay. The optimal extraction conditions were determined as follows: ethanol concentration of 54.5%, added acetic acid concentration of 13.1%, extraction time of 210 min, temperature of 40oC, 3 cycles of extraction and solid–solvent ratio 1/6 w/v. Using these extraction conditions, the experimental yield of TPC was 2391.1±5.9 mg GAE/100 g dry weight (dw) that was in close significant agreement with predicted value (p < 0.05). The experimental results were fitted to a second order quadratic polynomial model, and they have shown a good fit to the proposed model (R2 = 0.99). With these conditions, the antioxidant capacity assayed by 1,1–diphenyl–2–picrylhydrazyl (DPPH) radical–scavenging activity in term of IC50 value of extract was 108.1±2.9 μg dw/mL. The study result indicates the suitability of the developed model and the success of RSM in optimizing the extraction conditions.

An experiment was carried out at the experimental farm and laboratory of Can Tho University to evaluate feed utilization, nutrient digestibility and growth rate of crossbred rabbits. It was a factorial design in which the first factor was length of sugarcane stalk residue (SSR) (3 and 10 cm in length) fed ad-libitum, and the second factor was different supplement of operculina turpethum (OT) (0, 100, 200 and 300 g/rabbit/day) with three replications and four rabbits per experimental unit. Results show that SSR intake was slightly higher (P>0.05) for rabbits fed 3 cm in length and gradually decreased with increasing supplement of OT in the diets (P

Optimizing agricultural land use for sustainable development is one of the important challenges for agricultural management, especially in areas with changing socio-economic and environmental conditions. Optimization techniques have been researched for solving land use problems; however, there is not any appropriate optimization and spatial distribution method for agricultural land use. Therefore, the main objective of this study was to develop the ST-IALUP model between the open source application-LandOptimizer and ST-LUAM model to solve the multi-objective optimization and distribution for agricultural lands. The ST-IALUP model was built to target land use decisions in agricultural areas by the choice of planning scenarios. The case study for supporting agricultural land use planning in Tran De district pointed out that the ST-IALUP model not only assisted multi-objective optimization based on the factors of socio-economic, environmental and risk of LUT but also determined both land use allocation map and the new increasing area LUTs map for Tran De district to support planners in implementing solutions. The study results provided a reliable basis for supporting the decision-making process for planners in district-level agricultural land use planning in the Mekong Delta.

The aim of this study was to investigative the effect of different growth stages of Pouzolzia zeylanica plant (young and mature plant) on bioactive compounds content (anthocyanin, flavonoid, polyphenol and tannin); the content of pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoids); antioxidant activity through some measurable values such as antioxidant ability index (AAI), ferrous reducing ability power (FRAP) and scavenging capacity 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical; as well as the color parameters of stem and leaves (L*, a*, b* and DE). The results showed that the content of anthocyanin, flavonoid, polyphenol, chlorophyll a, chlorophyll b, total chlorophyll and carotenoids of young plant was higher than that of mature ones, and had statistically significant difference (P0.05). There was no difference in antioxidant capacity between young and mature plants when performed with scavenging free radical (DPPH) or total reducing power (AAI), but there was significant difference when performed with ferrous reducing ability power (FRAP) method. In addition, there were also statistically significant differences in average values of a* and b* between young and mature, stem and leaves, and these two parameters were related to the content of anthocyanin, chlorophyll, carotenoid in Pouzolzia zeylanica plant.

Four local male cattle with average live weight of 290 kg were arranged in a Latin-square design with four treatments, which included fresh water hyacinth (WH) replacing rice straw at levels of 0, 25, 50 and 75% in the diets [dry matter (DM) basis]. The aim of this study was to find out the optimum level of fresh WH in cattle diet based on nutrient digestibility, rumen parameters, nitrogen retention and daily weight gain. The multi-nutrient cake containing 323 g CP/kg DM was supplemented in all the diets to adjust the daily crude protein intake to 210 g/100 kg body weight. The results of the study showed that daily DM, organic matter and metabolizable energy intakes were significantly different (P0.05) among the treatments. The daily nitrogen retention and weight gain were 0.482, 0.502, 0.510 and 0.480 g/kgW0.75 and 250, 334, 448 and 403 g for the WH25, WH50, WH75 and WH100 treatments, respectively. The results indicated that feeding the fresh WH to replace rice straw up to 75% in local cattle diet could improve metabolizable energy intake, nutrient digestibility and growth performance. The optimum level of WH replacement to rice straw in the diet was 50%.

Bio-fertilizer formulation from indigenous microorganism communities (IMOCs) is great suitable methods applied widely in the eastern part of world for the extraction of minerals, enhancement of agriculture and waste management although its functionalities have been unknown. The aim of this study was to assess phosphate solubility, indole-3-acetic acid (IAA) biosynthesis and nitrogen fixation efficacy of various IMOCs from different farming systems within Soc Trang province of Vietnam. Phosphate solubilization and synthesis IAA abilities of collected IMOCs were investigated in National Botanical Research Institute's Phosphate (NBRIP) liquid media containing tricalcium phosphate (TCP) as the sole P source. This medium was supplemented with and without tryptophan (100 mg/L) for IAA synthesis capability evaluation while nitrogen fixation ability was tested in liquid N-free Burks media. Besides, nifH functional gene involving in nitrogen fixation was also detected by specific polF/polR primers. The results showed that all surveyed IMOCs were found to solubilize TCP with a various extent, and the maximum amount of P2O5 solubilized was over 2,000 mg/L. In regard to the IAA biosynthesis, all IMOCs were able to biosynthesize considerably IAA with the highest IAA amount of 56.6 mg/L. All surveyed IMOCs had potential in nitrogen fixation when the primer amplified nifH gene successfully from DNA of collected IMO, and eight out of 15 IMOCs proved their nitrogen fixation with quantity varied between 1.0 and 6.5 mg/L N. In conclusion, all collected IMOCs had beneficial functions for plants like phosphate solubility, IAA synthesis and biological nitrogen fixation which can be exploited for enhancing soil fertility and plant growth.

The study was conducted to determine the prevalence and antimicrobial resistance of Salmonella from pigs and farm environments in Vinh Long province from June 2017 to December 2017. Salmonella was isolated from 240 fecal samples and 640 environmental samples (feed, water, barn floor and wastewater) at household and pig farms. There were 76/880 (8.64%) positive samples with Salmonella. Among them, Salmonella was detected from 35/240 fecal samples (14.58%) which was higher than that from 41/640 environmental samples (6.40%). The prevalence of Salmonella in healthy pigs was (8.88%) lower than that of diarrheic pigs (61.54%). The Salmonella positive isolation rate from pigs in household farms was 20.20% (62/307) higher than that of pigs in commercial farms with 2.44% (14/573). Salmonella positive rate was increased by age; the highest rate was in sow with 37.50% (12/32 samples), following by growing pigs 12.16% (18/148 samples) then post weaning pigs 10.34% (3/29 samples), and lowest rate was in suckling pigs 6.45% (2/31 samples). Salmonella isolation from pigs and environments were resistant to trimethoprim/sulfamethoxazole (64.47%), chloramphenicol (52.63%) and ampicillin 46.05%). The multidrug-resistant phenotypes (resisting against 2-7 antibiotics) were observed from 55/76 Salmonella isolates, such as Bt - Cl, Am – Bt – Ac and Am – Bt – Cl were the most frequent phenotypes. Besides, these strains were highly sensitive to ceftazidime (100%), levofloxacin (100%), colistin (96.86%), amikacin (97.37%), cefuroxime (97.37%), ofloxacin (96.05%), doxycycline (93.42%), gentamicin (92.11), streptomycin (89.47%), and following to tetracycline (75.00%), amoxicillin/clavulanic acid (75%) and ampicillin (53.95%).

Through the process of studying the Pangasius belly hydrolysate by neutrase enzyme, the belly Pangasius was defated; it showed a kinetic index Vmax = 1.283 μmol tyrosine per minute, Km = 0.377 g protein with reliability R2 = 0.997, enzyme/substrate ratio (E/S) (0.652 mg enzyme/0.975 g protein). Hydrolysis efficiency of tyrosine according to enzyme/substrate 42.69%, ortho-phthaldialdehyde efficiency of the enzyme/substrate was 52.51% at 240 minutes. Subsequently, the belly Pangasius protein hydrolysate was dry-sprayed at 180°C. After drying, the moisture and water activity of dried fish protein hydrolysates were 6.05% and 0.55, respectively. Both commercial peptone and protein hydrolysate from Pangasius belly were used as nitrogen components for Bacillus subtilis growth media at the time from 0 to 72 hours at 37oC and pH = 7, then the powder medium hydrolysed by enzyme neutrase was higher than the commercial peptone medium. In addition, the result from the activity of enzyme protease in the two media for at time of 4, 8, 12, 16, 20, 24 hours, at 37oC and pH = 7 showed that the activity of protease in hydrolysed protein medium from the belly Pangasius was similar to commercial peptone.

The objectivie of this study was to evaluate adding levels of biochar on methane, carbon dioxide and digestibility of para grass in in vitro incubation. The experiment was arranged in a completely randomized design with three replications of five treatments which are different levels of biochar added to para grass (Brachiaria mutica) at 0, 0.5, 1.0, 1.5, and 2.0%, namely BC0, BC0.5, BC1, BC1.5, and BC2, respectively. The incubation lasted for 72 hours with measurements of gas, methane and carbon dioxide production at 0, 6, 12, 24, 48 and 72 hours. The results showed that the total CH4 production (ml/g) and organic matter digestibility (%) after 72-hour incubation significantly decreased (P

The aim of this research was to study the hydrolysis capacity of proteins in white shrimp head meat by using commercial alcalase and flavourzyme enzyme. A response surface methodology with two concentration factors, alcalase enzyme (10÷30 UI/g) and flavourzyme enzyme (20÷30 UI/g), including 11 experiments was utilized to optimize the hydrolysis process. In addition, such experimental conditions of pH (6.9 - 7.2), temperature (53 - 58°C), and hydrolysis time (2 – 4 hours) were also investigated by using the response surface methodology with 17 experimental units. As a result, the hydrolysis solution was achieved with a high hydrolysis efficiency (90.19%) and good antioxidant activity (86.16%) by using the following optimal conditions of pH (7.01, temperature (54.94°C), hydrolysis time (2.96 hours), alcalase enzyme (19.42 U/g), and a flavourzyme (32.09 U/g).

The effect of germination process on α–galactosidase activities, oligosaccharides and reducing sugars contents in soybean seeds was investigated. Soaked soybean seeds were germinated at 25oC in dark condition for 72 hours. Samples were collected every 12 hours during germination for analyzing the α–galactosidase activities, which was monitored with a synthetic substrate ρ-nitrophenyl-α-D-galactopyranoside (ρNPGal). The freeze-dried samples were prepared for determination of raffinose, stachyose, sucrose by thin layer chromatography, and reducing sugars were assayed by reaction with nitro salicylic acid. After soaking, the activity of α–galactosidase increased1.84 times compared to that in the soybean seeds and reached maximum value (164.3±2.5 U/100g, db) after 12 hours of germination. The increase in α–galactosidase activity led to the decrease in raffinose and stachyose contents during soaking and germination. In addition, the degradation of these undesirable components followed the first order exponential equation (R2 = 0.97–0.99). Sucrose content remained after soaking and up to 12 hours of germination and reduced significantly after that. The final result of the hydrolysis of raffinose, stachyose and sucrose was significant increase in reducing sugars that can be used as energy-source during germination of soybean seeds.