Vol. 2 No. 4 (2019): Vietnam Journal of Agricultural Sciences

A pot experiment was conducted in a net house to evaluate the effects of drought stress (a 20-day water withholding treatment from 100-120 days after planting) on the growth and physiology of five sugarcane cultivars. The results showed that water stress at an early stage significantly affected sugarcane growth and physiology. Water stress resulted in reductions in plant height, stalk diameter, and leaf number of sugarcane, in addition to reductions in the photosynthetic pigment content, Fv/Fm, and SPAD (Soil Plant Analysis Development) readings after the 20-day withholding water period (120 DAP), and in stem, root, and leaf fresh weights, and leaf area at 150 DAP. Besides, drought stress led to increases in stomata density and decreases in stomata length. Variation was also found among the cultivars in response to water stress. Significant genotypic differences in stem fresh weight and leaf area under water stress among the cultivars were observed. The highest value of stem fresh weight under stressed conditions was recorded in ROC22 (50.6 g), followed by QĐ159 (46.5g), ROC16 (46.2g), ROC10 (46.1g), and VL06 (44.4g). However, the highest DTI was recorded in ROC16, followed by VL06, ROC10, QĐ93-159, and ROC22, respectively.

The extraction of oil from passion fruit seeds with acetone, ethanol, ethyl acetate, isopropanol, and hexane was studied. The effects of the variables, namely type of solvent, material to solvent ratio, temperature, and extraction time, were investigated. The highest extraction yield was 78.52%, which was obtained using ethyl acetate with a material to solvent ratio of 1/10 at room temperature (28oC) for 4h using a shaker. This yield was similar to that obtained when using hexane as a solvent. Our results indicate that ethyl acetate can replace the conventional hexane solvent in the extraction of oil from passion fruit seeds. The high content of polyunsaturated fatty acids in passion fruit seed oil suggests that this product has good potential for use in the human food, cosmetic, and pharmaceutical industries.

The livestock insurance program for dairy farmers in Vietnam targeting various acute diseases began in 2011 as a pilot project; however, due to vaccination campaigns, outbreaks of such diseases are rare. The objective of this study was to investigate the effects of mastitis and reproductive failure-which chronically affect the farming economy-on the decision to participate in the insurance program. A survey involving a questionnaire and milk sampling from apparently healthy animals was conducted on the 38 participating and 59 non-participating dairy farms in the livestock insurance program in Ba Vi, Hanoi, Vietnam, in August 2014. Microbiological tests were performed to detect sub-clinical mastitis, whereas the questionnaire was administered to collect information regarding farm management and the occurrence of clinical mastitis and reproductive failure over the previous three months. There were no significant differences in the proportion of farms having cows with clinical mastitis (insured: 8/38 farms, 21.1% vs. non-insured: 13/58 farms, NA = 1, 22.8%, p = 1) and repeat breeders (insured: 16/36 farms, NA = 2, 44.4% vs. non-insured: 20/57 farms, NA = 2, 35.1%, p = 0.49) over the previous three months. The proportion of farms having cows with sub-clinical mastitis at the time of the survey was also not significantly different between insured (5/38 farms, 13.2%) and non-insured (7/59 farms, 11.91%) farms (p = 1). Based on the obtained results, neither endemic disease nor farm management is respectably involved in the decision of farms to participate in the animal insurance program targeting acute animal infectious diseases.

Aquaculture production in China has made large contributions to the global total volume of fish for human consumption. The developed mariculture fish species large yellow croaker (Pseudosciaena crocea) is the highest economic marine fish of China. As a schooling fish, large yellow croaker (LYC) usually migrates from northeast China to the southeast seacoast to over-winter. Indeed, there are several culture systems that can be applied for large yellow croaker, which should simulate the natural habitat for this fish species. The nutrition management of LYC has attracted researchers to study their nutrient requirements, growth, and other physiological characteristics. Here, we review the general biology (geographic distribution and habitat), hatchery development, aquaculture systems, and nutrition management of LYC. The paper aims to underpin the most significant investigations and highlight the future prospects for the LYC aquaculture industry in China.