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49 results on '"Hai, Tran Ngoc"'

28. Influence of salinity on nursery-phase whiteleg shrimp (Litopenaeus vannamei) reared in a biofloc system.

Author

Hoa, Nguyen Van, Tảo, Chau Tai, Terahara, Takeshi, and Hai, Tran Ngoc

Subjects
WHITELEG shrimp, SALINITY, SHRIMP culture, SURVIVAL rate, SHRIMPS, APPROPRIATE technology
Abstract

This study aimed to determine the effect of salinity on the survival rate and growth of whiteleg shrimp postlarvae reared using biofloc technology. The experiment included four treatments at different salinities: 10‰, 15‰, 20‰, and 25‰. Each treatment consisted of three replicates. Shrimps were reared using biofloc technology with a C/N ratio of 15:1 and additional sugar treatment. Shrimps were cultured in 500 L-tanks with a stocking density of 2,000 inds/m3. The initial weight of shrimp was 0.006 g. After 30 days of rearing, the growth rates of shrimp differed significantly among treatments (P < 0.05). The results showed that the length (4.54 ± 0.06 cm), weight (0.79 ± 0.04 g), and survival rate (91.5 ± 1.0%) were significantly greater (P < 0.05) for the shrimp reared in the treatment salinity of 15‰ compared to the other treatments. Therefore, rearing whiteleg shrimp at a salinity of 15‰ using biofloc technology is appropriate. [ABSTRACT FROM AUTHOR]

Published
2022
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30. Biofloc microbiome

Author

Tinh, Tran Huu, Momoh, Taofik Adeiza, Kokou, Fotini, Hai, Tran Ngoc, Schrama, Johan W., Verreth, Johan A.J., Verdegem, Marc C.J., Tinh, Tran Huu, Momoh, Taofik Adeiza, Kokou, Fotini, Hai, Tran Ngoc, Schrama, Johan W., Verreth, Johan A.J., and Verdegem, Marc C.J.

Abstract

Biofloc prokaryotic and eukaryotic communities, Biofloc prokaryotic and eukaryotic communities

Published
2021

47. Screening antioxidant activity of seaweed extracts collected in the Vietnamese Mekong Delta for dietary supplementation of whiteleg shrimp Litopenaeus vannamei

Author

Anh, Nguyen Thi Ngoc, Kitheka, Charles Wambua, Giang, Huynh Truong, Hai, Vu Hung, Khoa, Tran Nguyen Duy, Viet, Le Quoc, and Hai, Tran Ngoc

Abstract

This study assessed the yield and antioxidant ability of seaweed extracts harvested from the Vietnamese Mekong Delta for the dietary supplementation of whiteleg shrimp, Litopenaeus vannamei. In the first experiment, a two-factor test was randomly designed, including three seaweed types (Chaetomorpha linum, Enteromorpha intestinalis, and Gracilaria tenuistipitata) combined with three solvent types (100°C hot water, 90% methanol, and 90% ethanol). The results indicate that C. linum extracted in hot water had a relatively high yield, total phenolic content, and the best antioxidant capacity, as illustrated by DPPH free radical scavenging, ferric chelating, and ferrous reducing power assays. In the second experiment, a feeding trial used the crude hot water extract of C. linum for juvenile L. vannamei. This experiment consisted of five treatments in which commercial feed was supplemented with crude extract at levels of 0 (control), 0.3, 0.6, 0.9, and 1.2%. Shrimp (mean weight: 0.65±0.09 g) were raised in a total of 15 containers (volume: 500 L) with a density of 200 ind./m3. After 60 days of culture, shrimp survival showed no significant difference across treatments. Moreover, shrimp fed a 0.6% C. linum hot water extract diet had a significantly higher growth rate, production, feed efficiency, and digestive enzyme activity (trypsin, lipase, and amylase) than the control and other groups. Interestingly, polynomial regression revealed that a 0.52% extract diet gave the optimal feed conversion ratio, which was considered the appropriate supplementation level for L. vannamei.

Published
2023
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48. Vietnamese Primary School Teachers’ Needs for Professional Development in Response to Curriculum Reform

Author

Thi Xuan Nguyen, Yen, Van Ha, Xuan, and Hai Tran, Ngoc

Abstract

This qualitative study explored the needs for teacher professional development (PD) of Vietnamese primary school teachers. The participants of the study were ten teachers at ten different primary schools in a large city in Vietnam. The data included in-depth individual interviews with the participating teachers. Qualitative analysis of the interview transcripts revealed several interesting insights into the teachers’ perspectives on PD, their regular PD activities, and their needs for PD. All the teachers considered PD essential for their demanding teaching job. They reported having attended various PD programs and activities provided by their schools, and the department of education and training at the province and district levels. They also participated in several teacher professional learning communities available on the Internet. However, the teachers expressed a need for more PD programs and activities, especially in the context of curriculum reforms. Notably, they preferred to attend PD courses which were more practical and relevant to their work. In addition, they highly appreciated the hands-on activities and opportunities to interact with teacher trainers and educators. These findings were interpreted and discussed in relation to the sociocultural contexts of Vietnamese primary education. The study also discussed implications for PD course designers and teacher educators in Vietnamese primary school contexts and beyond.

Published
2022
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49. Potential uses of gut weed Enteromorpha spp. as a feed for herbivorous fish.

Author

Anh NT, Hien TT, and Hai TN

Subjects
Animal Feed analysis, Animal Nutritional Physiological Phenomena, Animals, Diet veterinary, Perciformes growth & development, Tilapia growth & development, Tilapia physiology, Vietnam, Water Quality, Aquaculture methods, Digestion, Perciformes physiology, Ulva chemistry
Abstract

Three separate experiments were performed to assess the potential use of gut weeds Enteromorpha spp. as a food source for herbivorous fish. The fresh or dried gut weeds were used as a direct feed to replace commercial feed in an alternative approach for feeding spotted seat (Scatophagus argus), red tilapia (Oreochromis sp.), and giant gourami (Osphronemus goramy) juveniles for 60 days, 45 days, and 56 days, respectively. Four feeding regimes were applied to triplicate tanks and fish was fed daily either commercial feed or gut weed: (1) single commercial feed everyday as a control treatment, (2) single gut weed daily and 2 alternative feeding regimes where (3) 1 day commercial feed and 1 consecutive day gut weed or and (4) 2 consecutive days gut weed. The results indicated that survival of experimental fish was not affected by the feeding treatments. Growth performance of the S. argus fed single gut weed was not significantly different from the control group (P>0.05). Growth rates of Oreochromis sp. and O. goramy in the alternative feeding treatments were comparable to the control treatment. Application of the combined feeding regimes, feed conversion ratio could be reduced from 26.1 to 57.8%. These results indicated that fresh and dried gut weed can be used as a feed to substitute commercial feed for herbivorous fish. Moreover, using gut weeds as a feed could improve water quality in the rearing tanks.

Published
2013

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