The Journal of Agriculture and Development

Identification of sanchi samples based on DNA barcodes

Thanh Dong Pham — 2024-06-21

For centuries, sanchi has been used in traditional medicine in East Asian countries to promote health and fitness. To identify and distinguish sanchi from adulterants, this study was conducted to determine the sequence of four DNA barcodes. The PCR products of the four barcodes were 330 bp (rbcL), 822 bp (matK), 484 bp (trnH-psbA), and 438 bp (ITS1). Genetic relationship analysis showed that the four DNA barcode regions had high similarity with other Panax species. Three barcodes, matK, trnH-psbA, and ITS1, confirmed that the studied samples belonged to Panax notoginseng, distinguished from Panax pseudoginseng, and can be used to identify Panax notoginseng.

Evaluating the growth performance of all male sex reversal and mixed ser tilapia (Oreochromis niloticus) cultured in earthen ponds in Binh Phuo province, Vietnam

Ngoc Loi Nguyen — 2024-06-21

The study was conducted to evaluate the growth performance, survival rate and yield of all male sex reversed and mixed sex Nile tilapia (Oreochromis niloticus) cultured in earthen ponds for 180 days. The reversed sex and mixed sex fingerlings (mean weight 7.43 ± 0.35 g) was randomly stocked in six earthen ponds (1,000 m²/pond). The stocking density maintained was 5 fish/m². The stocked fish were fed a commercial pellet feed containing 35% crude protein. The feeding rate was adjusted according the size of fish, 5% at the beginning to 3% at harvest. Water environment parameters including dissolved oxygen (DO) (4.3 ± 0.8 mg/L), temperature (30 ± 0.7°C), NH₃ (0.18 ± 0.2 mg/L), and pH (6.9 ± 0.5) were always within the appropriate range for the normal growth and development of tilapia. The growth rate of sex reversed tilapia was significantly higher (P < 0.05) than that of mixed tilapia throughout the experiment. The harvest weight and length of reversed sex tilapia were 410.5 ± 5.15 g and 25.48 ± 0.48 cm, respectively, and were significantly higher than that of mixed sex tilapia (P < 0.05). The survival rates and feed conversion ratio (FCR) of mono and mixed sex were 90.1% and 89.9%, respectively, but no significant differences were observed (P > 0.05). The relationship of fish lengths and weights expressed by power function revealed that the slope of the length weight regression lines was normal for reversed sex (2.72) and mixed sex Tilapia (2.93) with the high correlation coefficient (> 0.9). The findings of this study demonstrate that reversed sex tilapia has better growth performance compared to mixed sex tilapia. Therefore, reversed sex fingerlings should be used in commercial farming to increase tilapia production.

Investigation of small-scale farming status of Tire track eel (Mastacembelus favus) in the Mekong Delta, Vietnam

Huu Yen Nhi Nguyen — 2024-06-21

Tire track eel (Mastacembelus favus) is an economically important freshwater fish in the Mekong Delta. However, there is a lack of academic information about the current farming status, feed, and feeding related to this species in the region. Therefore, a field survey of small scale farming of tire track eel was conducted in An Giang, Dong Thap, Hau Giang and Kien Giang provinces of Vietnam. The objective of the survey was to determine the current farming practices information on households, especially the feed and feeding status of tire track eel in order to improve and develop a suitable feed for this fish in the future. The results showed that most of the small-scale farmers cultured fish in earthen ponds with or without plastic liners. Tire track eels were fed with feeds of other species and typically fed 3 - 5 times/d during the fingerling stage, and twice per day during the grow-out period. In terms of feed ingredients, crude protein contents in the feeds were 39.5 - 45.5% while crude lipid contents were 7.7 - 12.7%. Feed conversion ratios of tire track eels were 2 - 5. The farming periods of fish were 11.8 - 14 months when the fish reached the harvesting sizes of 318.2 - 421.4 g/fish, with the survival rates of 40 - 80%. It took 2.5 months to cultivate the fingerling stage (around 3 g/fish) from the fry with the survival rate of 55.7%. It was reported that this species was raised with a simple technique and got less illness compared to other fish species. However, the main reason of fish deaths during farming period related to management factors such as poor water quality due to decomposition of uneaten feed in water or lacks of dissolved oxygen due to high stocking density or power supply failures.

Bacterial species causing subclinical mastitis in dairy cows: rapid identification and antimicrobial susceptibility testing

Hong Son Ly — 2024-06-21

This study aimed to determine subclinical mastitis (SCM) caused by bacterial species, using chromogenic culture media and to assess the antimicrobial resistance rate in the isolated bacteria. From March to December 2023, 143 milk samples were collected from 71 Holstein Friesian cows with SCM across seven dairy farms in Ho Chi Minh City and Binh Duong province. Milk samples were incubated in triplicate chromogenic culture media to identify SCM caused by microorganisms. Our study revealed that 39.2% (56/143) of the samples had the growth of a single morphology, 26.6% (38/143) exhibited growth of two distinct morphologies, 9.0% (13/143) were found to be contaminated, and 25.2% (36/143) showed no growth. The isolated Streptococcus species were Strep. agalactiae 34.3% (49/143), Strep. uberis 22.4% (32/143), and Enterococcus spp. 1.4% (2/143). Besides, S. epidermidis 20.3% (29/143), S. saprophyticus 14.7% (21/143), and S. aureus 4.2% (6/143) were frequently isolated among Staphylococcus species. For gram-negative bacteria causing SCM, E. coli 2.8% (4/143), Klebsiella spp. 1.4% (2/143), and Pseudomonas spp. 4.2% (6/143) were the most isolated. Regarding antimicrobial susceptibility testing, the resistance rate of each bacterial species to each antibiotic tested differed for Staphylococcus, Streptococcus, and gram-negative bacteria. Staphylococcus aureus was not resistant to gentamycin, florfenicol, and marbofloxacin. The resistance rate of S. epidermidis to gentamycin, florfenicol, trimethoprim sulfadiazine, and amoxicillin-clavulanic acid varied from 10.3% to 17.2%. Marbofloxacin and trimethoprim-sulfadiazine were excellent choices in treating SCM caused by S. saprophyticus because of their low resistance rate (10.3 - 13.3%). Streptococcus uberis was sensitive to the combined antibiotic amoxicillin-clavulanic acid. The resistance rate of Strep. agalactiae to this combined antibiotic (amoxicillin-clavuclanic acid) was the lowest (10%). Pseudomonas spp. was resistant to the tested antibiotics. Our study suggests that identifying bacterial species and conducting antimicrobial susceptibility tests play a crucial role in improving the treatment effectiveness for bovine SCM.

Snail composition and its cercariae in rice field of Hoc Mon district, Ho Chi Minh City, Vietnam

Cu Thien Pham — 2024-06-21

The research on snail composition and their cercariae by morphological analysis method in Xuan Thoi Thuong rice field of Hoc Mon district, Ho Chi Minh City, Vietnam was carried out in the wet season of August 2022 and the dry season of February 2023. A total of 993 snails were collected and 11 snail species belonging to 9 genera and 5 families were classified. There were 9 snail species collected in the wet season and 7 snail species found in the dry season. Lymnaea viridis and Bithynia siamensis were infected with trematode (cercariae stage) with the combined prevalence of 14.3% and 4.1%, respectively. The other nine snail species had cercariae free. Two cercariae morphotypes were discovered from snails including Xiphidio cercariae and Echinostome cercariae. More research on snails and their cercariae in other waterbodies should be done in Hoc Mon district and other places to identify the snail diversity and sources of trematodes affecting fish culture and human health.

Influence of the supplementation of macadamia oil cake powder on nutritional and sensory qualities of bread

Van Chuyen Hoang — 2024-06-21

Although macadamia oil cake (MOC) is a by-product of macadamia oil processing, this material still has high nutritional value, making it a promising ingredient for food products. This study aimed to investigate effects of the MOC supplementation at different ratios on physical properties, nutritional composition and sensory quality of bread. The results show that the addition of MOC led to increases in protein, ash and fat content, while carbohydrate content was lower in the supplemented bread. The specific volume and springiness of the bread were significantly affected by the MOC supplementation while no significant change in hardness and spread ratio was observed (P < 0.05). For the sensory quality of fortified bread, the differences in color, flavor, texture and overall acceptability among 4 levels of MOC addition were insignificant, except for the taste score. Microbiological analyses also confirmed that the MOC supplemented bread product met microbial safety standards. The obtained results suggest that the bread sample with 20% MOC addition (9.35 g protein, 12.32 g fat, 46.13 g carbohydrate, 4.29 g dietary fiber and 332.77 kcal per 100 g) should be selected for developing high nutritional bread product.

Comparison of the physicochemical properties and biological compounds of acerola fruit varieties grown in Vietnam through the various maturation stages

Thi Ngoc Diep Duong — 2024-06-21

The objective of the present study was to find the changes in physicochemical properties, bioactive compounds, and antioxidant activity of acerola fruits under different cultivars (i.e., Brazilian acerola (Malpighia emarginata D.C) and sour acerola (Malpighia glabra L.)) and maturation stages (unripe, half-ripe, and ripe). For any species, the study found an increase in total soluble solid and a* value, whereas there was a decrease in the content of bioactive compounds (i.e., polyphenols, flavonoids, vitamin C), total acidity, and antioxidant activity, which followed the maturation development of fruits. Briefly, the unripe acerola fruits (Brazillan cultivar) were an excellent source of vitamin C (32.97 mg/g) and phenolic content (25.62 mg GAE/g).

Inventorying and proposing solutions for street tree management in Thu Duc city, Ho Chi Minh City

Thi My Tien Duong — 2024-06-21

Tree inventory plays an essential role in the urban landscape master plan. It serves as the foundation for data acquisition that supports the planning strategy and decisions relating to the community’s interests, particularly in recently established cities like Thu Duc city. This research was carried out from October 2021 to December 2022 in this city and aimed to inventory to gather qualified information for managing the city’s street trees. The study used an inventory form of street trees including criteria such as name, family, diameter at breast height (DBH), total height, and indicators of vitality and distance from trees to infrastructure. By this form, 287 streets were surveyed. The total number of investigated trees was 31.023 trees belonging to 65 species and 24 flora families, of which the species with a high percentage (from 10% or more) were Dipterocarpus alatus, Hopea odorata, Peltophorum pterocarpum, and Lagerstroemia speciosa. The most numerous plant family was Fabaceae. These trees typically had a height of less than 10 m, with a DBH of less than 20 cm. Many streets did not guarantee the distance between trees and infrastructure, particularly the distance to the electrical systems. The survey also showed that the majority of trees were healthy and grow healthily. From the current situation of Thu Duc city street trees, three solutions must be prioritized in order to improve street trees in this city.