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Efficiency of Hard Clam (Meretrix lyrata)Farming in EarthenPonds in Nam Dinh and Ben Tre Provinces

Le Van Khoi, Le Thanh Ghi, Chau Huu Tri, Chu Chi Thiet

Received: 27-06-2019 / Accepted: 16-09-2019
A study ontheefficiency of hard clam farming in earthen ponds was conducted in Ben Tre and Nam Dinh provinces to assess the growth, survival rates,economic efficiency and food safety of farmed clamsin commercial production. Two earthen ponds (total areaof 1.8ha) in Ben Tre province and four earthen ponds (total area of 2.2 ha) in Nam Dinh province were used in thisstudy. The results showed that the growth rate of clamswas seasonally affected and it fluctuated in the range of 1.27-1.39 g/month. The survival rate of clams varied from 70.65 to 90.00% and there existeddifference in two study areas. The clamscultured in Ben Tre province had higher survival rate than those in Nam Dinh province. The harvested size varied from 48 to 55 individual/kg and the harvested clamsmet the standards of food hygiene and safety. The clam productivity in two areas ranged from 22.08 to 24.55 tonnes/ha/crop and the profit varied between19.86 million VND/ha to 26.86 million VND/ha and/crop. The marginalcost benefit ratioin Ben Tre (0.28) were higher than that in Nam Dinh (0.22). The results of the study confirmed the ability of the clam farming model in earthen pond in the coastal areasof Vietnam.
Effects of Stocking Densities in Hapa-Net on the Growth andSurvival Rate of Black Apple Snail, Pila polita

Le Van Binh, Ngo Thi Thu Thao

Received: 20-06-2017 / Accepted: 10-08-2017
This study was conducted to evaluate the effects of different stocking densities on growth and survival rate of black apple snail, Pila polita. There were 4 stocking densities and 3 replicates per treatment as follow: 50, 100, 150, 200 ind./m2. Snails with initial weight (1.6 g), shell height (20.7 mm) and shell width (14.3 mm) were reared in hapanetand fed 50% pellet (Proconco, 18% protein) + 50% vegetable (spinach, 3.4% protein). After 4 monthsof culture, at low stocking densities, the survival rate was higher than that of high density treatments (77.4, 75.6, 73.8 and 68.5% at density 50, 100, 150 and 200 ind./m2, respectively with) (p <0,05). Rearing at 50 ind./m2, snails reached highest body weight, shell height and shell width (31.09 g; 54.90 mm and 43.38 mm, respectively) compared to 100 ind./m2(30.65 g; 53.42 mm and 43.14 mm), 150 ind./m2(30.03 g; 53.61 mm and 42.32 mm) and 200 ind./m2(28.35 g; 53.09 mm và 41.41 mm). At the stocking density of 50 ind./m2snails also hadlowest FR (2.62). It was similar to the density of 100 ind./m2(2,80) and significantlydifferent(p <0.05) compared to 150 ind./m2(3.04) and 200 ind./m2(3.45). Snails raised at 50 ind./m2yieldedthe highest profit (19.535 VND/m2),followedby 100 ind./m2(18.122 VND/m2) and was significantlydifferent(p <0.05) compared to 150 or 200 ind./m2(10.487 - 14.280 VND/m2). The results from this study provide the basic information for further studies to develop culture techniques for Black apple snailculturein the Mekong Delta.
Weaning Age Effects on Larval Performance of Clownfish (Amphiprion perculaLacepede, 1802)

Tran Van Dung, Tran Thi Le Trang

Received: 26-12-2016 / Accepted: 29-05-2017
The effect of weaning from conversion of live food (Artemia nauplius) to pellets on growth and survival of clownfish larvae (0 - 60 days old) was evaluated in this study. The same weaning regime was applied to larvae at day 14, 18, 22, 26 and 30 after hatching. The results showedthat clownfish larvae could start digesting pellets effectively from day 18 after hatching and still achieved optimal growth and survival rate. However, the use of the pellets at the earlier stage (day 14) caused a decrease in growth compared to weaning day 22, 26 and 30 post hatching (P < 0.05). The starting time of weaning had no significant effect on survival rate, ranging from 52.2 to 57.8% (P > 0.05). The use of pelletsreduced the period of weaning to 18 days post hatching as compared to30 days using Artemia nauplius,thereby improvingthe economic and technical efficiency in larval rearing.
Effectof Stocking Density on Growth Rate and Survival of White Leg Shrimp, Litopenaeus Vannamei,Raisedon Indoor Composite Tanks

Nguyen Phuong Toan, Vu Van Sang, Nguyen Viet Vuong, Nguyen Quang Tuat, Dang Thi Diu, Doan Thi Nhinh, Tran The Muu, Vu Van In

Received: 18-02-2013 / Accepted: 20-04-2013
The effect of stocking density of white leg shrimp SPF (Litopenaeus vannamei) was carried out at different density of 40, 60 and 80 PL15/m2 for 75 days. Each treatment was replicated three times in 4m2 indoor composite tank system and feeding ratio of 10-15% body weight with CP pellets containing 38% crude protein and four times a day. During the experiment, water temperature varied between 28 and 31ºC, whereas salinity ranged from 20-24‰ in biosecurity condition. Water in the culture tanks was renewed 50% weekly. The highest growth rate in weight was found in treatment of 40 heads/m2 (1.54 g/week), followed by 60 heads/m2 (1.47 g/week) but the rate for 30 heads/m2 (1.16 g/week) was lowest. Similarly, the survival rate of shrimp stocking at 40 heads/m2 ranked highest (79.7 ± 2.6%), followed by 60 heads/m2 (78.7 ± 2,9%) and the lowest rate for the 80 heads/m2 (70,3 ± 3,3%; P<0.05). Nevertheless, there was no significant difference in the survival rate between shrimp raised at 40 heads/m2 and 60 heads/m2 (P>0,05). Size variation (CV) for 40 heads/m2 (727 ± 1.52%) and 60 heads/m2 (8.22 ± 2.5%) were considerably lower than that for 80 heads/m2 (12.9 ±2.7%; P<0.05). However, there was no considerable disparity in feed conversion rate among the three treatments (P>0,05). All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBV and IHHNV.
Study on Alternative Methods to Green Malachite in Treatment of Ichthyophthirius multifiliis

Truong Dinh Hoai, Nguyen Van Tuyen, Nguyen Thi Huong Giang, Pham Thi Lam Hong

Received: 19-12-2015 / Accepted: 20-09-2016
The mixture of Green Malachite (MG) and formalin is the most effective chemical used to treat Ichthyophthirius multifiliis and other prasites infecting fish.However, MG was prohibited to usein aquaculture due to its potential risks to the environment, animal and human health. The prohibited use of MG has caused many difficulties to treat this parasite and other aquatic diseases. This study was conducted to examine a new, environmental friendly, safe and effectively method alternative to MG. Formalin 25 ppm (F25) was combined with a high oxidizing PHA (15% peracetic acid, 25% hydrogen peroxideand 25% acetic acid) at different concentrations of 1, 3, 5, 7, 10 ppm (PHA1, PHA3, PHA5, PHA7, PHA10) and the mixture was used to experimentally treat theronts (in vitro), and mature Ichthyophthirius multifiliis (trophonts) parasitized on Grass carp (in vivo), following with comparison to mixture of Green malachite and formalin (F25 + G0.25). The in vitrotest results show that the mixtureof F25 + PHA10 could kill 96.5% theronts within 48h. For in vivotest, treatments were conducted 72h post infection. After 10 days of experimental treatment, the control group (infected without treatment) had a high mortality rate (85.56%).In contrast, the F25 + G0.25 showed high efficiency in controlling this parasite with 94.43% fish survival. The mixtures F + PHA were effective to mitigate mortality rate compared to the control group, in which the mixture of F25 + PHA10 resulted in highest survival rate (92.23%), following with low prevalence and infection intensity, 5.13 and 1.81 parasites/sample at 40 x magnification, respectively. In addition, Ichthyophthirius multifiliis exhibited changes in morphology and moving behaviour. Results of following 10 days post treatment showed that fish treated with F25 + PHA10 recoveredeffectively, stopped mortality and probably created immunity against this parasite.
Effects of Calcium Supplement to Water on Growth, Survival Rate and Productivity of Apple Black Snail (Pila polita)in Nursing Phase

Le Minh Tue, Nguyen Thi Thanh Thuy, Ha Thi Hue

Received: 26-09-2023 / Accepted: 12-06-2024
This research was conducted to evaluate the effect of different calcium concentrations on the growth of black apple smail in the nursing phase. The experiments were designed with four treatments and three replicates as follow: treatment 1 with 5mg Ca2+mg/l, treatment 2 with 10mg Ca2+mg/l, treatment 3 with 15mg Ca2+mg/l and the control (0mg Ca2+). The supplement of calcium was practiced every seven days. After 40 days, treatment 2 reached the highest weight, height, and body width with 2.22g; 20.75mm; 17.35mm, respectively, but statictially non-significance between treatments (P >0.05). The survival rate of snails also reached the highest value with treatment 2 at 87.3%, treatment 1 at 82.1%, treatment 3 at 78.3% and the lowest at 0% with control treatment. Similarly, the productivity of black apple snails was recorded the highest in treatment 2 at 4.04 g/m2, treatment 3 at 3.66 g/m2, treatment 1 at 2.02 g/m2and the lowest for the control at 0 g/m2.
Evaluation of Growth and Development of Tisue Culture-derived Plants ofFour GerberaDaisy (Gerbera jamesonii) Cultivars

Pham Thi Huyen Trang, Phung Thi Thu Ha

Received: 21-03-2023 / Accepted: 05-10-2023
Gerbera, which is diverse in colors and types of flowers, is a high valuecut flower in both the domestic and international markets. This study aimed to evaluate the growth and development of tisue culture derived plants of four cultivars of Gerbera (Red, Pink, Orange, and Yellow). The experiment was designedin a randomized completeblock design. The study results showed that, in the nursery stage, tissue culture plantlets had 83.33-100% survival rate, with 6.9-8.3 leaves/plant, and plant height in the range of 6.44 to 7.28cm after 1.5 months of transplanting. In the production stage, the survival rate of all four Gebera cultivars reached 100%, with 9.4-11.4 leaves/plant, and 26.95-34.05cm in height after 3.5 months of transplanting. The flower stalk diameter of four Gebera cultivars ranged from 5.55 to 6.13mm, and the flower stalk height reached from 39.67 to 46.14cm. The maximum head diameter of four cultivars reached 8.65-9.41cm. The head longevity from bud to fade was29.20-31.70 days. The head inflorescence longevity from fullbloom to fade was8.80-12.40 days. All four studied Gerbera cultivars grewand developed well and wereless affected by pests and diseases, suitable for planting in Gia Lam, Hanoi.
Effects of Stocking Density on Growth Performanceand Body Surface Temperature in Broilers

Che Minh Tung, Nguyen Thi My Nhan

Received: 17-04-2023 / Accepted: 29-08-2023
The objective of this study was to evaluate effect of stocking density on growth performance and surface temperature of different body parts in broilers. A total of 1000 one-day-old broiler chicks (Ross 308) were assigned to two treatments in a completely randomized design. The stocking density treaments were (1) 9 chicks/m2(SD 9) and (2) 13 chicks/m2(SD 13). Each treatment had 20 replicate pens (50% female and 50% male/pen). The experimental results showed that there was no difference in average daily weight gain between two treatments (P >0.05). However, broilers in the SD 9 group had a better feed conversion ratio than those in the SD 13 group (P = 0.048). The survival rate of broilers in the SD 9 group (99.8%) was greater (P <0.001) than that of broilers in the SD 13 group (95.8%). Moreover, the body surface temperature of broilers in the SD 9 group (32,3C) was much lower (P = 0.003) than that of broilers in the SD 13 group (36.0C). A similar trend was also observed for the shank and neck surface temperature of broilers (P <0.05). Briefly, the stocking density of 9 broilers/m2improved the feed conversion ratio, survival rate and body surface temperature of broilers as compared with the stocking density of 13 broilers/m2.
Experimental Rearing of Common Carp (Cyprinus carpio) Fingerlings using Biofloc Technology with Carbohydrate Source from Molasses and Corn Starch

Do Dang Khoa, Nguyen Tuan Duy, Kim Van Van, Thai Thanh Binh

Received: 05-04-2022 / Accepted: 15-08-2022
This study was conducted to investigate the water quality, growth, survival rates and feed conversion ratio (FCR) when rearing common carp (Cyprinus carpio) fingerlings by using biofloc technology (BFT) with carbohydrate source from molasses (RĐ)and corn starch (BN). Common carp fingerlings (33.5 ± 1.15 g/fish) were randomly stocked in 9 tanks (267 l/tank) at a density of 150 fish/m3(40 fish/tank) with three experiments: experiment 1 (BFT-RĐ) and experiment 2 (BFT-BN) were reared in biofloc system with molasses and corn starch, respectively, as a carbon source with C:N ratio of 20:1, whereas the control experiment (ĐC) was reared at similar intensity without biofloc technology and exchange 50% water/day. Fish was fed on demand with 35% protein diet. The result showed that after 60 days rearing water quality in BFT-RĐ was maintained better than that in BFT-BN and the control. The survival rate (98.33± 1.44%) and average daily weight gain (0.69 ± 0.05 g/fish/day)of common carp in BFT-RĐwere highest in BFT-RĐ (P <0.05)compared with the other treatments. Common carp in BFT-RĐ had the lowest FCR (1.53 ± 0.02) (P <0.05) comparedto BFT-BN (1.58 ± 0.02) and the control (1.73 ± 0.03).
Experimental Study on all-maleGiant Freshwater Prawn (Macrobranchium rosenbergiiDe man, 1879) Two-phase Culturein Hai Phong

Dang Thi Thanh, Nguyen Trung, Nguyen Thi Tai

Received: 12-10-2021 / Accepted: 05-07-2022
This study was conducted with the aim of providing a farming procedure with appropriate technical criteria applicable to Hai Phong and Northern provinces. Stocking density in phase 1 was 150 juveniles/m2for the period of 50 days. Phase 2 was started with two different stocking densities: 15 prawns/m2and 20 prawns/m2, two replica for each for the same culture time of 134 days. The results show that the water quality in cultured system including water temperature, water pH, transparency, dissolved oxygen, NH3, NO2and H2S, aerobic total bacteria, Aeromonas, Pseudomonas, phytoplankton was in the acceptable limit for the growth of giant freshwater prawn. The survival rate of phases 1 reached 80% after 50 days. In phases 2 after 134 days, the survival rate and harvested size of prawns for the density of 15 and 20 prawns/m2 were 71% and 80.93 g/prawns; 68.5% and 76.96 g/prawns, respectively. Culture of all-male giant freshwater shrimp in two-phase with stocking density of 15-20 prawns/m2obtained high efficiency and could be applied to production.
Experimental Study on all-maleGiant Freshwater Prawn (Macrobranchium rosenbergiiDe man, 1879) Two-phase Culturein Hai Phong

Dang Thi Thanh, Nguyen Trung, Nguyen Thi Tai

Received: 12-10-2021 / Accepted: 05-07-2022
This study was conducted with the aim of providing a farming procedure with appropriate technical criteria applicable to Hai Phong and Northern provinces. Stocking density in phase 1 was 150 juveniles/m2for the period of 50 days. Phase 2 was started with two different stocking densities: 15 prawns/m2and 20 prawns/m2, two replica for each for the same culture time of 134 days. The results show that the water quality in cultured system including water temperature, water pH, transparency, dissolved oxygen, NH3, NO2and H2S, aerobic total bacteria, Aeromonas, Pseudomonas, phytoplankton was in the acceptable limit for the growth of giant freshwater prawn. The survival rate of phases 1 reached 80% after 50 days. In phases 2 after 134 days, the survival rate and harvested size of prawns for the density of 15 and 20 prawns/m2 were 71% and 80.93 g/prawns; 68.5% and 76.96 g/prawns, respectively. Culture of all-male giant freshwater shrimp in two-phase with stocking density of 15-20 prawns/m2obtained high efficiency and could be applied to production.
Effect of β-Glucan and Probiotics on the Survival rateandResistance of Tilapia (O. niloticus)to Streptococcusagalactiae

Kim Minh Anh, Nguyen Van Duy, Truong Dinh Hoai, Kim Van Van

Received: 09-08-2021 / Accepted: 10-01-2022
This study was conducted to investigate the effects of β-glucan and probiotics supplementation on the survival rate and disease resistance of tilapia (O. niloticus) juverniles. The experiment was set up with four treatments consisting of the control treatment (ĐC), the mixture of beneficial microorganisms (NT1), the mixture of β-glucan (NT2) and 50% NT1 + 50% NT2 in NT3 and was replicated thrice. Fish were randomly stocked in 12 units of 8.0 m3(2 × 4 ×1m) cement tank and fed the experimental diets for 30 days. Experimental fish were infected with bacteria S. agalactiae at109 CFU/kg of feed. Infectious bacteria were re-isolated, re-examined and the antibiogram tested after treatment to assess the disease resistance of experimental batches. The trial results showed that disease appeared later in fish fed the β-glucan supplemented diet with lower mortality rate, and higher recovery rate after medicinal treatment than those fed the probiotic and control diets.
Study on Maturation Broodstock Culture and Artificial Reproduction of Yellowcheek (Elopichthys bambusaRichardson, 1844)

Nguyen Hai Son, Vo Van Binh, Dang Thi Lua

Received: 25-03-2021 / Accepted: 22-06-2021
The study on maturation broodstock culture and artificial reproduction of yellowcheek (Elopichthys bambusaRichardson, 1844) was conducted from 12/2019 - 8/2020 at the National Freshwater Broodstocks Center. The aim of this study was to identify suitable foods for culturing maturation broodstocks, optimum hormone dose and appropriate incubation equipment for producing yellowcheek seeds. The results indicated that the use of chopped silver carp as food for culturing yellowcheek broodstock in the pond provided the higher maturation rate of broodstocks than using a food formulation consisting of 50% silver carp + 50% pellet feed and using 100% mixed pellet fish with 40% protein. Hormone dose of 60µg LRH-A + 10mg DOM/kg female gave the highest ovulation rate with the effect of hormones from 5-6 hours at 27-31C. Using Weiss incubators (Cycle tank) for incubating eggs showed a higher hatching rate (84.4%) and survival rate after 13 days (56.7%) in comparison with trays (68.7% hatching rate, survival rate 45.7%).
Use of Rotifer as Feed for Striped Catfish (Pangasianodon hypophthalmus) Fry

Huynh Thanh Toi, Huynh Thi Ngoc Hien, Nguyen Thi Hong Van

Received: 28-02-2020 / Accepted: 09-12-2020
The objective of this study was to assess the growth rate of some rotifer species and possibility to use them as live food for nursing of striped catfish (Pangasianodon hypophthalmus) fry. Three species of freshwater rotifers including Brachionus angularis, B. palaand B. calycifloruswas mass-reared and compared to brackish species B. plicatiscurrently used as live food for striped catfish fry in the Mekong delta. Then, these four rotifer species were used as feed for striped catfish fries within the first three days, followed by Moina used until the end of the experiment. The population of B. palaand B. calyciflorusattained its maximum density (increased 03 times) for day 03 and 04, respectively. Meanwhile, B. angularisandB. plicatilisreached its maximum density (increased 06 times) for day 07 and 09, respectively. The results on fish study showed that the highest survival was obtained (24.1%) in B. angularisfed fish, whereas the lowest survival was obtained in B. calyciflorusfed fish. The weight of B. angularis fed fish was significantly higher than B. calyciflorusfed fish, but the difference was not significant compared to B. plicatilisor B. palafed fish. The results of this study indicated that B. angularisis the optimal live food for striped catfish fry.
The Effect of Live Food on Larvalof Malabar Grouper (Epinephelus malabaricus) in Early-Stage Age

Hoang Nhat Son, Pham Cong Hai, Kim Van Van

Received: 06-03-2020 / Accepted: 13-04-2020
This study aimed to determine the types and densities of live foods that affect the growth and survival of grouper larvae (Epinephelus malabaricus) from 0 to 12 days old. In the first experiment, the feeding regime consisted of four types of live feeds (three rotifer strains: Proales similis, Brachionus rotundiformis, Brachionus plicatilisand the trochophore of Pacific oyster) for larval nursing. The results showed that super small rotifers (Proales similis) (size 50-60µm) were most suitable for larval rearing of grouper to 12 days old. In experiment 2, the densities of rotifer (P. similis) at 10 individuals/ml and 15 individuals/ml were showed the best results in nursing of larval grouper, denoted as the survival rate of 12-day-old larvae was 8.3-11.7%; the population’s subdivision coefficients and the average length of grouper larvae were 4.4-8.8% and 601.8-603.6μm, respectively.
Safety and Efficacy of Vaccine Han-Streptila in Commercial Tilapia

Ho Thu Thuy, Nguyen Huu Vu, Tran Thi Khanh Chi, Vu Duc Hanh, Nguyen Viet Khong, LaiThi Lan Huong

Received: 01-10-2018 / Accepted: 14-04-2019
The objective of the present study was to determine the safety and efficacy of vaccine Han-Streptila incommercialtilapia by injection (in Hau Giang, Tien Giang and Dong Thap provinces) and by oral route (in An Giang, Vinh Long and Dong Thap provinces). The control, immune and safe groupswere set up in each province. The safety of the vaccine was determined by observing the abnormalities of experimental fish; the efficacy of the vaccine was determined by comparing the final cumulative mortality between thevaccinated groupandthe control group during the trial or after challenge test. This also was evaluated throughrelative percentage survival(RPS).The results showed that the vaccine hadno effect on mortality and growth of fish. Thevaccineefficacy through injection with tilapia of 10g/p achieved 66.9% and oral route for fish 2.5g/p achieved 63.9% protection after 24 weeks. Therefore,HAN-STREPTILA vaccine tested in the South of Vietnam wassafe and highly effective.
Grow-Out Oyster Crassostrea belcherifrom Different Seed Sourcesin the Mangrove Forest Canal in Ca Mau Province

Ngo Thi Thu Thao, Tran Cam Loan

Received: 19-01-2018 / Accepted: 02-04-2018
The aim of the study was to evaluate the growth, survival rate, yield and quality of the oysters with seeds originated from Ben Tre, Tra Vinh and Ca Mau provinces. Oysters were cultured in the canal at Dam Doi district, Ca Mau province. Oysters with initial shell length of 8-9 cm were cultured in the net frame with a density of 140 individuals/m2. After 7 months of culture, the survival rate of Ca Mau oysters was higher than that of Ben Tre and Tra Vinh but the difference was not significant (p > 0.05). Ca Mau oysters reached highest shell length (120.20 ± 0.71 mm), total weight (147.37 ± 1.62 g) and productivity (22.62 ± 0.33 kg/m2) and there were significant difference with oysters originated from Ben Tre and Tra Vinh (p < 0.05). Quality evaluation of oysters showed that the appearance of shell, deliciousness of flesh oysters were not significantly different among oyster sources (p>0.05). Oysters derived from Ben Tre and Tra Vinh provinces can be cultured successfully in canal at Dam Doi district, Ca Mau province. The findings from this study are helpful for aquaculture practices in order to supply oyster seeds from the places that have spat collectors for oyster culture activities in Ca Mau province if neccessary.
Building Demonstration Model of Channel Catfish (Ictalurus punctatus) Pond Culture in Hung Yen Province

Kim Van Van

Received: 05-06-2017 / Accepted: 11-08-2017
From March 2016 to April 2017, under the cooperation between Vietnam National University of Agriculture and Extention Centre of Hung Yen province, a demonstration model of Channel catfish (Ictalurus punctatus) pond culture was developed. The modelwas caried out in six householdpondslocated in Van Giang, Khoai Chau, Yen My and Phu Cu districts, Hung Yen province. The Channel catfish with initial body weight of about 31,29± 0,56g/fish were stocked at three densities of 1; 1.5 and 2 fish/m2. Fish were fed commercial pellet containing 30-35% crude protein produced by CJ Master company (label withF8002 and F8003). Fish were fed twice daily at 8:00 AM and 16:00 PM at afeeding rate of 3 - 5% of body weight/day. Results showed that Channel catfish exhibited good growth rate (6.15-7.0 g/fish/day)and high survival rate (94.3-96.4%) and no disease occurred during the experimental period. The Channel catfish stocked ata density of 1 fish/m2yielded better growth, higher survival rate and highereconomic efficiency (248.3-257.4 million VND/ha/year) than those stocked atdensities of 1.5 and 2 fish/m2.
The Growth and Meat Quality of H’mong Chicken Raised by Industrial Farming

Nguyen Thi Phuong, Nguyen Van Duy, Vu Dinh Ton

Received: 22-03-2017 / Accepted: 24-04-2017
This study was carried out at the experimental farm of Vietnam National University of Agriculture from January to December, 2016 on H’mong chickens that were raised by industrial farming practices. H’mong chickens were raised in three lots in order to observe the survival rate, growth capacity, FCR and quality of meat. The results showed that H’mong chicken adapted well with industrial farming method, which supposedly contributed to the improvement in survival rate of chickens (94,1%). H'mong chickens had low weight and considerable growth speed. Average daily gain of H’mong chickens increased gradually from one to ten weeks of age and then decreased. From one to 12 weeks, H'mong chickens consumed 24.81 grams of feed per day and FCR was 3.1 kg of feed/kg live body weight. Twelve week-old roosters and hens achieved body weight at 1206,7g and 1026,7g, respectively. H'mong chicken is a dual-purpose breed, producing an amount of thigh meat 1.3 times greater than breast meat. The proportion of iron in H'mong chicken meat is high (136,8mg - 137,7 mg/100g) and there are eight essential amino acids in the meat.
Development of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on Different FeedPlants

Nguyen Thi Huong, Ho Thi Thu Giang, Pham Van Lam

Received: 28-12-2015 / Accepted: 05-05-2016
The development and life cycle of the beet armyworm, Spodoptera exigua(Hübner), were determined in the laboratoryusing six feedplants: welsh onion(Allium fistulosum); amaranth(Amaranthus viridis); mustard greens(Brassica integrifolia); mung bean(Vigna radiata); cabbage(Brassica oleracea capitata); and turmeric(Curcuma longa). The life cycle of S. exiguawas shortest on amaranth (24.2 days) and longest on turmeric (34.7 days). Feedplantsdid not significantly affectthe percentage of egg hatching or pupal survival. However, larval survival differed among feedplants, being highest on amaranth (87.6%) and lowest on turmeric (50.0%). The highest percentage of female progeny was recorded from S. exiguareared on welsh onion (46.7%) and the lowest for larvae reared on turmeric (36.1%). The fecundity of S. exiguafemales ranged from 174.3 eggs on turmeric to 453.8 eggs on amaranth. Within each feedplant, the increased pupal weight resulted in increasedfecundity. It means that the fecundity was significantly related tothefemale pupal weight ofS. exiguareared on test feedplants(r = 0,883 - 0,965).
Utilizing the Black Soldier Fly Larvae/Pre-Pupae (Hermetia Illucens)in Feeds for Snakehead Fish (Chana Micropeltes)

Nguyen Phu Hoa, Nguyen Van Dung

Received: 26-10-2015 / Accepted: 03-05-2016
The use the black soldier fly larvae/pre-pupae (Hermetia illucens) in feeds for snakehead fish (Chana micropeltes) wasinvestigated to assess the possibility of using asmeal for snakehead fishculture.The results showed that the highest survival rate was 84.0 ± 2.0% in treatment of NT3 (using pre-pupae). Treatment NT3 had the final weight of 78.0 ± 4.3 g and not significantlydifferentcompared with treatments using trash fish. FCR was lowest in the treatment NT3 (3.1 ± 0.1). The quality of the fish filletwas notdifferentbetween treatments.The use ofpre-pupae meal replacementin snakehead fish feedshowedthatthe survival rate ranged between67.3and84.7% and significant differences among treatments. The highest weight wasfound in NT20 (78.5 ± 1.0 g). FCR in the treatments of NT10, NT20 and NT30 were notsignificantlydifferentcompared to the control. The quality of fish filletNT10, NT20 and NT30 in treatmentswasnotsignificantlydifferentcompared to the control treatment.
Effects ofin vitroMutagenic Treatmentwith combination of EthylmethaneSulphonate(EMS) and Gamma Irradiationon genetic changesin Carnation(Dianthus caryophyllusL.)

Vu Hoang Hiep, Nguyen Thi Ly Anh

Received: 29-10-2013 / Accepted: 29-12-2013
The study on the effectsofcombined EMStreatment andgammaradiation on survival, growth, developmentandgenetic changes ofin vitro carnation (Dianthus caryophyllusL.)aimed at identifying effective methodstocreatematerialsfor carnation breeding.Stem segments with nodes of in vitro plantlets (cultivar “Princess”) were treated withdifferentEMSconcentrationsand gamma - raysirradiationdoses(EMS concentrationsfrom0.1 to0.4% andthe absorbed doseof gamma – rays from10-30Gᵧ).Eighttypesofshoot variants were obtained(A, B, C, D, E, F, Gand H).Inin vitrocondition, the height, number ofleavesandrooting abilityofthese shoot variantswerereduced graduallyin the following descendingorder:C> A> D> B> F> H>G.Thegrowth anddevelopmentofthese shoottypesin thenurserywere alsodifferent. The shoot type showed strongest growth, followed by typesA, D, F, B, and H. The type G did not grow and developinnurseryconditions. Some variantsoftheleafmorphology andcolor offlowers were isolated. The results showed that the rate of genetic changes was positively correlated with treatment dose. However, mutationrate increasedmainly intheundesirable types. The optimal treatmentdosewas 0.2% EMSand radiation of 20Gy. Thisdoseyieldedhigh survival rateandfrequency ofpotential varianttypesforbreedingnewcarnation cultivar.
Reproductive performance of the nucleus herd of stress negative Piétrain and Duroc swine raised at the animal farm of Hanoi University of Agriculture

Do Duc Luc, Ha Xuan Bo, Nguyen Chi Thanh, Nguyen Xuan Trach, Vu Dinh Ton

Received: 12-11-2012 / Accepted: 24-12-2012
A study was carried out from December 2011 to August 2012 to evaluate reproductive performance of nucleus herd of stress negative Piétrain (Piétrain) and Duroc pigs raised at the experimental farm of Hanoi University of Agriculture. A total of 35 gilts, including 21 Piétrain (11 with halothane genotype CC and 10 with CT) and 14 Duroc CC gilts were monitored for their reproductive performance. Piétrain boars (3 CC and 5 CT) were mated to Piétrain and Duroc gilts to produce Piétrain purebred and crossbred Piétrain x Duroc pigs. Results showed that genotype of the boar and the sow affected body weight and litter weight at birth and at weaning (P<0.05). Total number of pigs born, number born alive, number alive to weaning, individual bodyweight at birth, individual bodyweight at weaning, litter weight at birth, litter weight at weaning, survival rate at birth, survival rate to weaning were 9.91, 9.26, 8.11 piglets, 1.4, 6.4, 12.97, 51.96kg, 94.32 and 88.55%, respectively. Body weight and litter weight at birth and at weaning of piglets from Piétrain CC boars were higher than those of piglets from Piétrain CT boars (P<0.05). Reproductive performance was highest for Duroc CC sows, followed by Piétrain CC and lowest for Piétrain CT sows (P<0.05). Reproductive performance of the nucleus herd could be improved by using Piétrain CC boars mated to Piétrain CC sows and Duroc CC sows.
Effect of Rearing Density on Growth, Survival and Reproductive Performance of White Leg ShrimpBroodstockSPF (Litopenaeusvannamei)

Vu Van Sang, Nguyen Quang Trung, Vu Van In, Tran The Muu

Received: 03-09-2012 / Accepted: 15-12-2012
Three stocking densities of 6, 9, 12 heads/m2 of white leg shrimp broodstock SPF (Litopenaeus vannamei) were conducted in series of 14m2 indoor composite tanks at 28-29ºC and salinity of 28-30‰ under biosecurity control. Shrimp were fed 4 times a day with 50% blood worm and 50% fresh squid under water exchange of 100%/day. For induced breeding, eye ablation was applied to female after 30 days intensive rearing. There was no significant difference in growth, survival, rate of mating and spawning, fertilization and hatching rate among treatments (P>0,05). However, reproductive performance was significantly better in shrimp rearing at 6 and 9 heads/m2 than in those reared at 12 heads/m2 (P<0.05), reaching mature rate: 78.2-79.52%; number of spawning/female: 2.49-2.51; spawning fecundity: 152.600 - 153.200 eggs/female/spawn; average Nauplii/female: 123.9 - 127.5 x 103. Samples of broodstock shrimp, larvae and fresh food were found negative for WSSV, YHV, TSV, MBV and IHHNV.
Successful Application of Aeroponic System in Propagation of (Dendrobium nobile Lindl.)in the Nursery Phase

Tran The Mai, Nguyen Thi Son, Hoang Thi Nga, Nguyen Quang Thach, Nguyen Thi Ly Anh

Received: 25-09-2012 / Accepted: 19-11-2012
The application of aeroponic system for propagation of Dendrobium nobile Lindl. in the nursery phase has opened a new way for the development of the model in culturing this species in the northern provinces. The results showed that Dendrobium nobile Lindl. grown in the aeroponic system had the maximum adaptability, attaining survival rate of 100% after one month of planting in the spring, spring-summer and summer seasons. The aeroponic system can be applied for propagation in all cropping seasons around the year, while the hydroponic system or planting on the substrate cannot be done in the summer period. The plants grow better in the aeroponic nutrient solution III (improved from Knoop solution) with pH = 6.0 - 6.5; EC = 400 - 500 µs/cm; the spraying time of 2 minutes in 4 hours interval.

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