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Effect of Salinity Stress Shock on Growth and Survival of Black Tiger Shrimp(Penaeus monodon) at the Nursery Stage in the Biofloc Technology System

Huynh Thanh Toi, Nguyen Thi Hong Van

Received: 16-12-2017 / Accepted: 16-04-2018
This study was conducted to evaluate the effect of salinity stress shock on the growth and survival of postlarval black tiger shrimps (Penaeus monodon). The experiment consisted of 7 treatments. In five treatments for salinity stress, the shrimps taken from 20‰salinity condition were abruptly transferred to 5‰, 10‰, 15‰, 20‰, and 30‰salinity environment. In other two treatments the shrimps reared at 20‰salinity were acclimated for short time (in 3 hours) and long time (in 3 days) to 5‰salinity by adding tap water at stocking density of 2 shrimps/L . After 20 days of nursing, the water condition was in a suitable range for shrimp growth. The growth of shrimp in terms of individual length and weight by sudden salinity changes was not significantly different compared to the control, but the survival was significantly lower. The highest survival rate (98,3%) was observed in the control (20‰) and the lowest survival (60,7%) was found in the salinity shock from 20‰to 5‰. The results indicated that the survival of shrimps was adversely affected when salinity was suddenly shocked at high threshold by 10 - 15‰while the increase in salinity from 20‰to 30‰did not affect shrimp survival. Both short time and long time acclimation did not affect the shrimp survival and growth.
Effect of Stocking Density and Pellet FeedProtein Levels on Survival and Growth Rate of Snakehead (Channa sp.) at the Growing Market Size StageinCommercial Culture

Mai Van Tung, Nguyen Thi Hau, Tran Thi Nang Thu

Received: 15-03-2018 / Accepted: 17-12-2019
The objective of thisstudy was to determine the optimal growing density and pellet feed protein level applied during commercial snakeheadculture. The experiment was conducted at the Faculty of Fisheries,Vietnam National University of Agriculture (VNUA). Three replicate composite tanks (1m3/tank) were used for each experiment. The first experiment was carried out fromJuly to 30thAugust, 2017 to test the effect of stocking density at 70, 80 and 90 fish/m3(average weight of fish was 8,90± 0,45g/fish) on fish growthusingthe commercial pellet food of 42% protein. Four weeksaftergrowing at stocking density of 70 fish/m3,the survival rate, growing rate, and food conversion ratio (FCR) were99.05± 0.82%,0.33± 0.02 g/dayand1.18± 0.05, respectively.Thevalues of snakehead stocking at 80fish/m3were 99.17± 1.44%,0.40 ± 0.02 g/dayand1.19± 0.02,respectively and at 90 fish/m3were 99.26± 0.64%,0.36± 0.01 g/dayand1.34± 0.03, respectively. There was no significant difference of survival rate, growth rate and FCR of snakehead at three socking density levels after for 4 weeks of growing. The second experiment carried out from Augustto the end of December, 2017to test the effect of three protein levels (30%, 35% and 42% protein in pellet food) onthegrowth and survival rate of snakehead after 4 months of stocking at the growing density of 80 fish/m2(average weight of fish was 36,6± 1,11g/fish). After 4 months of stocking, fish culturedwith 42% of protein level showed the highest growth rate(1.99± 0.03g/day)and survival rate (86.67± 5.05%).At high protein level (42%) snakeheadhadthe fastest growth rate (total length of 1.34mm/day) and weight gain (1.99 g/day), food conversion ratio(1.19) and fish size distribution rate (10.3± 0.5).Research results show that nursing snakehead fish at density of 80 fish/m3, using food with 42% protein content for best growth and survival compared to the remaining stocking density and protein content.
Effect of Supplementation of Yucca Formulationon Growth and Survival Rate of Black Apple Snail (Pila polita)

Ngo Thi Thu Thao, Dang Van Danh, Le Van Binh

Received: 02-08-2022 / Accepted: 29-06-2023
This study was conducted to evaluate the effect of different concentrations of Yucca formulation on growth and survival rate of the black apple snail (Pila polita). The experiment consisted of 4 different treatments: (1) No Yucca supplement (Control); (2) Yucca supplement at 1 g/m3(Yucca1); (3) Yucca supplement at 2 g/m3(Yucca2); (4) Yucca supplement at 3 g/m3(Yucca3). Each treatment was conducted in three replicates. Yucca was added to the treatment tanks in 2 days interval for a period of 40 days of experiment. The black apple snails with initial weight and height of 0.04 g and 5.00 mm, respectively, were reared in composite tanks at a density of 200 snails/tank. Results after 40 days of culture showed that the survival rate of black apple snail was highest in Yucca3 (99.33%). There was a significant difference in survival rate between yucca-supplement treatments with the control (P <0.05). The height and weight of the black apple snails in Yucca3 (12.92mm and 0.50g) and Yucca2 (12.56mm and 0.46g) were higher and significantly different (P <0.05) from the control or Yucca1.
Effects of Stocking Densities, Types of Feed on the Growth and Survival Rateof Yellowcheck (Elopichthys BambusaRichardson, 1844) from fry to Fingerling Stage

Nguyen Hai Son, Vo Van Binh, Nguyen Huu Quan, Dang Thi Lua

Received: 27-08-2021 / Accepted: 01-03-2022
The experiment on nursing the Yellowcheck (Elopichthys bambusa) from larvae to fingerling at different stocking densities and feeds was carried out from July to December 2020 at the National Freshwater Broodstock Center to determine the appropriate stocking densities and suitable feeds used in the nursering and rearing of larvae and fingerlings Yellowcheck. The results showed that the larvae reared at a density of 4-5 fish/liter gave a higher survival rate and growth rate than those nursed at a density of 6-7 fish/liter. The survival rate and growth rate of fish stocked at a density of 0.6 fish/liter were higher than those stocked at a density of 1 fish/liter and 1.2 fish/liter. Using 100% zooplankton and 60% zooplankton feed combined with 40% small worms for rearing fry gave the survival rate and growth rate higher than using feed consisting of 60% zooplankton with 40% fishmeal. In the period of rearing fingerlings, using larvae silver carp, small worms, and 30% small worms combined with 70% larvae silver carp, had a higher survival rate and growth rate than using feed containing 70% of larvae silver carp and 30% of larvae shrimp (45% protein).
Effects of Stocking Densities and Crude Protein Levels of Feed on Survival and Growth Rates of Armorhead Catfish (Cranoglanis henriciVaillant, 1893) JuvenilesRearing in Composite Tanks

Kim Van Van, Doan Thi Nhinh, Nguyen Thi Thuy Hang

Received: 19-07-2018 / Accepted: 11-12-2018
A study was conducted to investigate the effects of different stocking densities and dietary protein levels on growth, survival rates and feed conversion ratio (FCR) of armorhead catfish (Cranoglanis henrici). Juvenile fish at the size of 16.79 ±0.92 g/fish and 39.91±0.75 g/fish, respectively,were located into two separated trials of three stocking densities(30, 45 và 60 fish/m3) and three diets containing graded levels of dietary protein (30, 35,and 40% CP). Triplicate groups of 8m3indoor circular tanks were used for arearing period of 60 days. Results showed that significant FCR was recorded at the density of 60 fish/m3(2.96) compared to that at the treatments of 45 fish/m3(2.81) and 30 fish/m3(2.68) while no significant difference (P>0.05) in growth was found. The fish weight ranged from 33.04 to 34.55 g/fish and survival rate washigher than 88% after 60 days of culture. The growth rates of fish fed protein levels of 35% (0.52 g/fish/day) and 40% (0.53 g/fish/day)were similar and significantly higher (P<0.05) than that of 30% (0.35 g/fish/day), while the survival rate over94% were recorded in all treatments. Based on the above results, it is recommended that armorhead catfish juvenile can be reared at stocking densities (in composite tanks) of 45-60 fish/m3and feed containing 35-40% crude protein isoptimalfor growth and FCR.
Effectiveness of Feeds Produced in Algae Biomass Ponds on Growth and Survival Rates of Ben Tre Clam (Meretrix lyrata)in Earthern Ponds

Le Van Khoi

Received: 04-06-2014 / Accepted: 13-07-2014
The effects of using different feed sources on the growth and survival of the Ben Tre clam were carried out in the earthen ponds of 500m2at a stocking density of 150 clam/m2. The experiment consisted of three food source treatments:natural foods in seawater through water exchange (CT1),food from algae biomass production in clam ponds(CT2), anda combination of natural foods through water exchange and food from algae biomass ponds (CT3). Results showed that NH4and chlorophyll-a concentrations in the treatment CT2 were 0.54 ±0.04 mg/L and 6.80 ±0.02 μg/L,respectively,andwas significantly (P<0,05) higher than those in CT1 and CT2 treatments. Growth and survival rates of the clam were highest inCT3 (0.60 %/day and 86.99%, respectively) and were significantly higher than those in the treatment CT2 (0.37 %/day and 75.45%). There were no significant difference between CT1 and CT2 in growth and survival rates (P>0.05). Research results recommended that combination of natural food source in seawater through water exchange and food from algae biomass pond are suitable for commercial farming of clams in pond.
Effect of Stocking Density on Growth and Survival Rate of Mouse Grouper (Cromileptes altivelis) Larvae FromFry to Fingerling Stage

Vu Van Sang, Tran The Muu, Le Xan, Pham Thi Lam Hong, TranThi Nguyet Minh, Nguyen Van Phong, Vu Van In

Received: 15-12-2013 / Accepted: 26-02-2014
The study was carried out to identify the most suitable stocking density for mouse grouper larvae (Cromileptes altivelis)from fry to fingerling stage. The larvae were reared at the densities of 10,20 and 30 individuals/l. Lower stocking densities, at 10 and 20 individuals/l weremore favorable forspecific growth rate (0.063 and 0.0625%/day), final total length (34.45 and 33.33mm)and survival rate (6.45 and 6.30%)(P<0.05). Results showed that the most appropriate density for rearing the mouse grouper from fry to fingerling stage is 20 individuals/l to optimize the growth, survival rate and economic efficiency.
Effect of Different Bottom Substrates on Survival Rate and Growth ofJuvenileSea Cucumber (Holothuria scabra) Cultured in Tanks

Nguyen Thi Ngoc Anh

Received: 01-01-2016 / Accepted: 17-07-2016
A study was performed to evaluate the effect of different bottom substrates on survival rate and growth of juvenile sea cucumber (Holothuria scabra) cultured in tanks. Experiment consisted of 4 treatments namely sandy substrate, muddy substrate, sand+mud sustrate mix with 1:1ratio,and brick substrate. Each treatment was repeated three times.Juvenile sea cucumberswithmean initial weight and length of 3.51± 0.14 g and 4.35± 0.51 cm, respectively,were kept in the 250- L tank and provided with slightly continuous aeration at salinity of 30 ppt, and stocking density of30 individuals/m2. After 75 days of culture, survival rate of sea cucumber in sandy, muddy and sand+mud substrates was in the range of 94.4- 100%, and not significantlydifferent(p> 0.05). Particularly, the sea cucumber in the brick treatment experiencedgradual mortalitywith time and complete death at day 62 of culture. The highest specific growth rate and daily growth rate in termsof length and weight of H. scabrain the sandy treatment was observed, and significantly different (p< 0.05) from other substrates. The results suggest that sandy substrate was most suitable while the brick wasnot appropriate for juvenile of sea cucumber H. scabra. Moreover, H. scabracould live and develop on the sand+mud and muddy substrates in tank conditions.
Effects of Plant Growth Regulators and External Factors on ThePropagation of Yellow Flower Camelia from Cuttings

Nguyen Van Viet, Nguyen Thi Huyen, Tran Viet Ha

Received: 27-07-2017 / Accepted: 11-12-2017
Yellow flower Camellia spp. are multiple purposeplantsof high economic values. They areused as a nutritious beverage, medicine and ornamental plants.This paper reported theresults of the propagation of three yellow flower camellia species by cuttings. The cuttings were sterilized withBenlat 0.5% for about 15 minutesandthentreated with plant growth regulators for 5 minutesand the results were recorded after 80 daysof experiment. With C. tamdaoensis,cuttings treatment withABT at a concentration of 200 ppm, C. flava and C. chrysanthaof cuttings treatment withβ-indol butyric acid (IBA) at 100 ppm and 150 ppm hadthe survival rate of72.24 - 83.33%, the shootregeneration rate of 71.33 - 83.67%, root formation rate of71.67 - 80.33% and the rooting index of8.39 - 9.77. The apicaland middle cuttings reached the survival rate of 75.67 - 80.33%, the root formation rate of 73.67 - 77.33% and coefficient of root formation was 6.23 - 6.87. With the medium containinggarden soil, rice husks and sand at 2:1:1 ratio, the survival rate and root formation rate were at 78.67 - 87.79% and 72.33 - 76.32%, respectively. Reduction of light by50 % shading resulted inthe survival rate of 87.43- 93.33%. The cutting method wassuitable forpropagatingyellow flower Camelliasfor germplasm conservation and development.
Effect of Dietary Fucoidan Supplementation on Growth of Nile Tilapia (Oreochromis niloticus)Fingerlings and Improvement of Survival Rate of Fish when Infected with Aeromonas veronii

Tran Anh Tuyet, Nguyen Thi Mai, Nguyen Thi Dung, Tran Thi Nang Thu

Received: 18-05-2021 / Accepted: 21-02-2022
The study was conducted to evaluate the effect of dietary fucoidan extracted from brown seaweed Sargassum swartziion growth, survival rate, feed conversion ratio (FCR), and disease resistance to Aeromonas veroniibacterium in Nile tilapia (Oreochromis niloticus) fingerlings. Fish (23.2 ± 2.7g) were fed the commercial feed (35%Pr) supplemented with fucoidan at various concentrations (0%, 0.05%, 0.1%, 0.5%) in triplicate for 6 weeks. The results have showed that fucoidan did not significantly affect (P >0.05) the growth, survival, and FCR during the feeding trial. At the end of nutritional trial, fish were infected with Aeromonas veroniiat dose of LD50 (7.82 ×104CFU/ml), fish were then monitored for 10 days, the mortality was daily recorded. After 10 days of challenge, the results showed that the survival rate was 76.6% and 80% for 0.1% and 0.5% fucoidan-fed fish, respectively, much higher than other groups (30% and 36.7% for Control and 0.05% fucoidan-fed fish, respectively) (P < 0.05). In conclusion, dietary fucoidan extracted from brown seaweed Sargassum swartziiat 0.1 and 0.5% enhanced the resistance of tilapia fingerlings against to Aeromonas veronii.
Assessment of Hatching, Survival and Growth Rate of Two New Common Carp Strains (Tata and Szarvas P3) Introduced from Hungary to Vietnam

Nguyen Hai Son, Vo Van Binh, Le Ngoc Khanh, Le Khanh Thuy Linh, Mai Van Tai, Nguyen Thi La

Received: 20-08-2021 / Accepted: 10-01-2022
The objective of the study was to evaluate the hatching rate, the survival rate of fry, fingerling, juvenile and the growth rate for breeding. Experiment on hatching, nursering and rearing of two introduced common carp strains (Tata and Szavas P3) from Hungary to Vietnam was carried out from July 2019 to December 2020 at the National Freshwater Broodstock Center. The results showed that the hatching time was 61.8 and 62.2 hours for Tata and Szavas strain, respectively; the figure of the hatching rate was 91.5% and 93.3%, and the deformity rate was 1.2% and 1.3%, respectively. The survival rate of Tata fingerling was 62.5% and of Szavas P3 was 67.5%. The survival rate of juvenile Tata carp was 48.7%, Szarvas P3 carp was 53.3%. The absolute growth in length and weight of Tata carp was 6.8mm/day and 0.51 gam/day, Szarvas P3 was 6.5 mm/day and 0.49 gam/day. After 12 months of culture, the average weight and length of Tata carp was 1670.5 ± 10.2 g/fish and 50.2 ± 7.1 cm/fish, Szavas P3 carp was 1565.5 ± 10.2 g/fish and 49.3 ± 7.7 cm/fish, the feed conversion ratio values was 2.0 for Tata and 1.9 for Szavas P3 carp. The results of hatching, nursering and rearing showed that Tata carp and Szavas P3 carp can be used as genetic material for selection breeding .
Effect of ArtemiaBiomass on Growth and Survival of Mud-Crab (Scylla paramamosain) in Crablet Stage

Huynh Thanh Toi, Lam Tam Nguyen, Nguyen Thi Hong Van

Received: 15-11-2019 / Accepted: 12-03-2020
The study was conducted to evaluate the time - of - use of Artemiabiomassfor feed affecting to tilapia fillet on survival and growth performance of mud-crab (Scylla paramamosain) in crablet stage. The experiment was performed with 5 treatments, forty crablets were individuallyreared in 250mL jar. Jars were drilled with many small holesto exchange waterand immersed in 150L tanks at 25 ‰ seawater. Artemiabiomass and tilapia fillet wereused as feed for crablets. Artemiabiomass was provided to crab in 20 days, 15 days, 10 days, and 5 days of culture and then they were provided with tilapia fillet to compare with crab in the culture where crablets wereprovided with solely fish fillet. After 20-day of culture, the results showed that the highest survival and growth performance (carapace widthand weight) was obtained in solelyArtemia-fed crabs, the growth performance was gradually decreased when the increased time to provide crabs byfish fillet, the lowest survival and growth performance was obtained in the culture where fish fillet was solely provided to crablets.
Effectiveness of Adding Fermented Gutweed Powder with Bacillus subtilison Rearing Blood Cockle (Anadara granosa)

Ngo Thi Thu Thao

Received: 08-10-2018 / Accepted: 14-06-2019
This study evaluated the effectiveness of adding different types of gutweed powder on the growth and survival rate ofblood cockle (Anadara granosa) at the juvenile rearing stage. The blood cockle seeds with initial shell length of 4.71 ± 0.03 mm were stocked in the PVC tanks with aeration system. There were four feeding treatments with triplicates eachas follow: 1) 100% algae from Tilapia-Green water system (GW, control treatment), 2) GW + gut weed powder, 3) GW + gutweed powder fermented with Saccharomyces cerevisiae, and 4) GW + gut weed powder fermented with Bacillus subtilis. After 60 days, the highest survival rate was recorded in GW (75.3%) and this was significantly different from other treatments (p0.05). The lowest survival rate was observed in GW + gut weed powder fermented with yeast (56.9%). Blood cockles obtained the highest shell weight and length in cockles fed GW+ gut weed powder fermented with B. subtilis(70.0 ± 1.6 mg and 6.18 ± 0.04 mm, respectively). Our findings suggested that adding gut weed powder fermented with B. subtiliscan improve the growth performance of juvenile blood cockles.
Effects of Dietary Lipid Levels on Metamorphosis and Survival of Mud Crab (Scylla paramamosain) from Zoeal 3 Stage to Instar 1 Crablet

Lam Tam Nguyen, Nguyen Thi Ngoc Anh, Tran Thi Thanh Hien

Received: 27-02-2018 / Accepted: 10-02-2019
A study on the effects of lipid levels in formulated feeds for mud crab (Scylla paramamosain) from zoeal 3 stage to instar crablet 1 was conducted in two rearing phases. From zoea 3 to the megalopal stage, the crabs were reared in 120 l composite tanks at salinity of 30‰ and stocking density of 50 Ind./l. From megalopal stage to crablet 1, the crabs were reared in the 50 l plastic tanks at salinity of 26‰ and stocking density of 10 Ind./l. The experiment was set up randomly with five isonitrogenous (53%) diets containing 6%, 8%, 10%, 12% and 14% lipid, and each treatment was done with five replicates. Mud crab larvae were fed experimental feeds combined with Artemianauplii during feeding trial. Results showed that the larval stage index of zoea 3 into zoea 5 stages varied in the range of 4.58-4.96 and the survival of megalopa was 5.45-7.40%, in which the 12% dietary lipid treatment attained highest values and was statistically different (P<0.05) compared to the remaining feeding treatments. Similarly, the highest survival, individual weight and carapace width of crablet 1 were obtained in the dietary lipid level of 12%. These results suggested that formulated diet containing 12% lipid could be considered as the most suitable diet for mud crab from 3 zoeal stage to instar 1 crablet.
Survival and Growth Ratesof White-Leg Shrimp Litopenaeus Vannamei(Boone, 1931) Reared in Freshwater and Saline Brackishwater

Le Viet Dung

Received: 24-09-2018 / Accepted: 07-11-2018
This study compared the growth and survivalratesofwhite-leg shrimp (L. vannamei) which were reared in freshwater at 0 ppt and in saline brackishwater at 30 ppt. PL34 shrimps were reared at the density of 1 individiual/L (200shrimp/m2) for 21 days. Shrimps of each treatment were reared in three 40 L tanks. Results showed that there was no significant difference in survival and growthratesofthe white-leg shrimpshrimpbetween the two treatments during the whole culture period. The survival rates of shrimp reared at 0 ppt and 30 ppt were 62.5 ± 10.9% and 69.17 ± 7.64%, respectively. The weight gain of shrimp reached113.33± 15.28% for shrimp at 0 ppt and 106,67± 11,55% for those at 30 ppt. The specific growth rate of shrimp at 0 ppt and 30 ppt was 3.78 ± 0.36% and 3.63 ± 0.28%, respectively.In conclusion, white-leg shrimp could be reared in freshwater 0 ppt.
Effect of Different Dietary Protein Levels on Growth and Reproductive Characteristics of Artemia franciscana Vinh Chau

Duong Thi My Han, Nguyen Van Hoa, Nguyen Thi Ngoc Anh

Received: 20-08-2015 / Accepted: 22-01-2016
This study was conducted to evaluate the effect of dietary protein levels in formulated feeds on survival, growth and reproductive characteristics of Artemia franciscanaVinh Chau in laboratory conditions. Experiment consisted of 7 feeding treatments including of commercial shrimp feed No. 0 (control feed) and 6 formulated feeds containing 20, 25, 30, 35, 40 and 45% protein. The experimental process was divided into two phases (1) Communal culture,from day 0 until Artemiareachessexual maturity to determine survival and growth. (2) Individual culture,Artemiacouples were reared in 50-ml Falcon tubes to record their reproductive characteristics and life span. After 14 days of culture, survival of Artemiawas not affected by the feeding treatments, varying in the range of 87.2-95.4%; and the total length of Artemiaattainedbetween 7.00 and 8.04mm, of which the treatments from 25% to 35% protein had significantly higher values (P> 0.05) compared to other feeding treatments. The lifespan of Artemia females wassimilar among feeding treatments (44.6-48.6 days). The reproductive period, total brood number and total offspring per Artemiafemale in the 30 and 35% protein treatments were significantly higher (P> 0.05) than the control, 20% and 45% protein treatments. These results indicated that formulated feed containing 30 to35% protein could be suitable feed for growth and reproductive performance of Artemia franciscana.
Effects of Stocking Densities on Growth, Survival Rates, Productivity and Economic Return of Clam (Meretrix lyrata) Reared in Earthponds

Le Van Khoi, Le Thanh Ghi

Received: 03-09-2014 / Accepted: 02-03-2015
Effects of stocking densities on the growth, survival rate and production efficiency of Meretrix lyrata commercial culture were investigated out in 500 square meter earth pond. Clam seeds (2.45±0.08g in body weight) were stocked at densities of 90, 150 and 210 individuals/m2and reared in a period of 12 months. Results showed that stocking densities did not affect the concentrations of DO, pH, NH4+and chlorophyll-a in culture ponds (P>0.05). Growth rate (0.57-0.60 %/day) of clam reared at 90-150 individuals/m2was significantly (P<0.05) higher than that at 210 individuals/m2(0.48 %/day). In contrast. clam productivity was higher at stocking densities of 150-210 individuals/m2(26.4-27.0 ton/ha) than at 90 individuals/m2(18.8 ton/ha). Survival rates were inversely propotional to stocking densities. The highest profit (138.6 million VND/ha) and benefit-cost ratio (32.13%) were observed at 150 individuals/m2and the lowest values (33.4 million VND/ha and 9.01%, respectively) at the density of 210 individuals/m2. This study suggests that the suitable stocking density in the earth pond culture of M. lyrata should be is 150 individuals/m2.
Effect of Density on Growth and Survival Rate of Orange Clownfish Larvae Amphiprion percula(Lacepede, 1802)

Tran Thi Le Trang, Tran Van Dung

Received: 25-03-2013 / Accepted: 26-04-2013
The study was conducted with five treatments (1, 2, 3, 4 and 5 ind./l) in order to identify the most suitable density for rearing orange clownfish larvae. Results showed that the fish reared at the densities of 1, 2 and 3 ind./l gave the highest specific growth rate (3,95; 3,87 and 3,77%/day, respectively), followed by the density of 4 ind./l (3,27%/day), the lowest at the density of 5 ind./l (2,99%/ngày); (p < 0,05). Similarly, the fish larvae reared at the densities of 1, 2 and 3 ind./l gave the highest total length (12,41; 12,09 and 11,76 mm), followed by the 4 ind./l (10,12 mm) and the lowest at 5 ind./l (9,32 mm); (p < 0,05). The fish larvae reared at the densities of 1, 2 and 3 ind./l obtained the highest survival rate (86,67; 83,33 and 78,89) followed by the 4 ind./l (55,83%) and the lowest at 5 ind./l (40,67%). In conclusion, the most appropriate density for rearing the orange fish larvae is 3 ind./l in order to optimize the growth, survival rate and economic efficiency.
Effect of Dietary on MatureRate of Female Otter Clam and Survival of Larvae(Lutraria philippinarum)

Vu Van Sang, Tran The Muu

Received: 05-11-2012 / Accepted: 23-02-2013
Dietary study onintensive rearing female otter clam(Lutraria philippinarum)stocked at a density of 30 pieces/m2 in 1m3 composite tank using Schizochytrium and fresh algae complex (Chlorella, Isochrysis, Chaetoceros) showed significantly higher percentage of mature and spawning in female otter clam fed on Schizochytrium (92,86 ± 1,50%) than that fed on fresh algae (74,06 ± 2,50%; P<0,05); however, there was no considerable difference in absolute fecundity, fertilization rate and rate of transformation to Trochophore larvae between the two treatments.Other experiment on survival rate of larvae otter clam fed on mix of Schizochytrium and Spirulina while the other fed on fresh algae complex (Isochrysis galbana, Chroomonas salina) from 4 to 21 days in 2m3 composite tank demonstrated no significant distinction in survival rate between the two experiments with survival of 21,6 ± 5,6% and 20,4 ± 3,5% respectively (P>0,05).
Growth and Survival Rate of SPF Vannamei Broodstock Candidate (Litopenaeus vannamei) Cultured in Indoor System at Different Stocking Density on Cat Ba Islands, Hai Phong

Vu Van Sang, Le Van Nhan, Nguyen Phuong Toan, Nguyen Huu Ninh, Tran The Muu, Vu Van In

Received: 03-08-2012 / Accepted: 25-09-2012
Litopenaeus vannamei) cultured in biosecurity system. Three groups of experimental shrimp (initial weigh 20.1±1.9 g/male and 21.4±2.2 g/female) were stocked at densityof10, 20 and 30 heads/m3in4m3indoor tank system. Each treatment was run in triplicate and fed with about 4% shrimp weight daily with pellet diets of CP 7704S and 7704P (38% crude protein), feeding four times a day. The water temperature ranged from 20.0 - 28.5oC and salinity ranged from 20-28‰. Water was renewed 80% volume weekly. The highest growth rate in weight was recorded in broodstock candidates cultured at 10 heads/m3(1.03 g/week/male; 1.11 g/week/female), followedby 20 heads/m3(0.89 g/week/male; 0.98g/week/female) and the least for 30 heads/m3(0.53 g/week/male; 0.62 g/week/female). Similarly, survival rate of shrimp at 10 heads/m3(71.7 ± 2.7%) ranked highest and the lowest rate for the 30 heads/m3 (60.1 ± 2.8%; P<0.05). Nevertheless, there is no significant difference in the survival rate between shrimp cultured at 10 heads/m3(71.7% ± 2.7%) and 20 heads/m3(71.5 ±3.0%; P>0.05). Size variation (CV%) and FCR recorded on 10 heads/m3 (CV%: 6.34 ± 1.12%; FCR: 2.78 ± 0.5) and 20 heads/m3(CV%: 6.68 ± 1.20%; FCR: 2.86 ± 0.3) were found remarkably lower than that for 30 heads/m3(CV%: 10.56 ±2.24%; FCR: 3.42 ± 0.8; P<0.05). The percentage ofshrimp harvested thatmet the criteria of broodstock was 67.1 ±2.6% and 66.7 ± 3.2% for the 10 and 20 heads/m3, respectively, whereasonly 23.1 ± 5.4% for the 30 heads/m3. All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBVandIHHNV.
Effects of Temperature on Embryonic Development and MalflormationEof Pompano,Trahinotus blochii

Tran Thi Mai Huong, Nguyen Thi Nien, Dam Thi My Chinh, Le Van Khoi, Nguyen Huu Ninh

Received: 27-07-2016 / Accepted: 28-12-2016
The experiment of the effect of temperatureeffecton embryonic development and malformation of pompano (Trachinotus blochii) was carried out at the Northen National Broodstock Center for Marine aquaculture oin Cat Ba, Hai Phong, Vietnam. Five temperature levels of 24oC, 26oC, 28oC, 30oC and 32oC were studied with 3 replicates each. The results showed that,there was a significant differencetbetween five treatments in terms of hatching, deformity and survival rates. The result indicated that the significant highest hatching rate was 47.7% at 24oC. The lowest deformity rate was observed at 24oC (3.3%) but no significant difference was found between 24oC, 26oC and 28oC. The survival rate was higher at 26oC (58,6%) and 28oC (58,2%) after five days of post-hatching than other. The results show that sSuitable temperatures for pompano incubation are ranged from 24oC to 28oC. At 26oC and 28oC, the lowest deformity rate (3,98 - 4,20%) and the highest survival rate (10.48% and 10.69%) after 40 days of post hatching were recorded. From this study, the temperature rangedfrom 26 - 28oC are recommended for pompano rearing.
Influence of Dietary Peptidoglycan and Probiotics Supplementattion on Growth Performance, Feed Utilization,Survivaland Hematological Parameters in Nile Tilapia(Oreochromis niloticus)

Nguyen Thi Mai, Litpaya Nettavongsa, Le Thi Cam Van, Ho Hai Yen

Received: 16-03-2023 / Accepted: 23-05-2024
The present study was conducted to evaluate the effects of dietary co-supplementation of peptidoglycan and probiotics on growth performance, survival, feed utilization, and hematological parameters in Nile tilapia. Commercial feed specialized for tilapia were supplemented with peptidoglycan and probiotics at various concentration (g/kg of diet): 0; 3+3; 5+3; 5+5; 3+5 corresponding to experimental treatments: NT1, NT2, NT3, NT4, NT5. Nile tilapia juveniles were fed on the experimental feed for 4 weeks at a ration of 5% body weight; the feed amount was daily recorded. During the feeding period, fish were weekly weighed to monitor the fish growth. After a 4-week trial, blood samples were collected for hematological analysis; the fish number and weight were used to determine the survival rate and fish growth. Results show that the co-supplementation of probiotics and peptidoglycan induced positive effects on the fish survival, growth, and feed conversion ratio, in which fish fed 3g peptidoglycan + 3g probiotics displayed the best results.
Factors Affecting the Efficiency of Rapid Vitrification of in vitroBovine Embryo

Nguyen Thi Ngoc Anh, Nguyen Duc Truong, Nguyen Thi Thu Trang, Nguyen Van Thanh, Do Thi Kim Lanh

Received: 17-04-2023 / Accepted: 29-08-2023
The research was conducted to improve the quality of in introbovine embryo vitrification. Bovine oocyteswere matured thenfertilizedwith frozen-thawed semen at1, 2or 5× 106sperm/ml for 6 hours to find the optimal conditions. Theblastocysts were then rapidly frozen in the medium using TCM199+BSA (Tissue culture medium-199+Bovine serum albumin) or DPBS+FBS (Dulbecco's phosphate-buffered saline+Fetal bovine serum). There was no significant difference in the maturation rateof oocytes matured in BO-IVM or TCM-199 medium. In vitrofertilized bovine oocyteswith frozen-thawed sperm atconcentration of 2 × 106sperm/ml for 6 hours gave the highest fertilization and blastocyst rate. The survival rate after thawing of bovine embryosfrozenin DPBS+FBS and TCM199 + BSA medium was92.96% and 82.71%, respectively, however, there was no significantdifference between the groups. Thehatching rate after thawing of embryos vitrified in TCM 199 + BSA medium reached 54%, significantly higher than that ofembryos vitrifiedin DPBS+FBS medium (28.8%). Inthe gene-edited embryo group, the number of survival embryos after thawing reached 96.03 % compared to 88.82 % in the IVF group. The source of oocytesalso affected the survival rate of embryos after thawing.
Survival rate and final weight at harvest of hybrid combinations of Nile tilapia (Oreochromis niloticus) as influenced by genetic background of parental populations

Nguyen Hong Diep, Vu Van Sang, Vu Hong Su, Nguyen Cong Duong, Tran Thi Kim Oanh, Do Son Tung

Received: 13-12-2021 / Accepted: 05-04-2022
This study was designed to estimate the additive genetic, heterotic, and maternal effects on harvest body weight and survivalof tilapia (Oreochromis niloticus) combinations in a 4x4 complete diallel cross involving four populations, i.e. NOVIT, GIFT, China, and the Philippines. Mass spawning method was applied to produce hybrid combinations (with 60 males and 60 females per cross) for testing on harvest body weight and survival at three locations, Quang Nam, Tien Giang and Bac Ninh. A total of 8,001 Nile tilapia was evaluated after a grow-out period of 6 months. A linear mixed model was used to estimate strain additive genetic, heterotic, and maternal effects for body weight and survival at harvest. Research results showed that the non-additive genetic (heterotic) effects were small and not significantly different from zero for the traits studied, whereas the additive genetic effects were statistically significant (P <0,001). Based on heterotic and additive genetic effects among crosses, pure crosses between Novit and Novit showed the highest additive genetics effects, while different strain cross between Novit and the Philippines indicated the best additive genetics effects.
Effects of Commercial Feed Replacement with ArtemiaBiomass on the Growth and Survival of Mudskipper (Pseudapocryptes elongates)Fingerlings

Huynh Thanh Toi, Le Vu Dang, Nguyen Thi Hong Van, Pham ThiTuyet Ngan

Received: 29-03-2019 / Accepted: 25-10-2019
The study was conducted to assess the effective use ofArtemiabiomassto replace commercial feedinnursing of mudskipper (Pseudapocryptes elongates). The experimentswereset up comprising 5 treatments with the percentageof Artemiabiomass in dry matter in a feeding ration: 0% (NT1), 25% (NT2), 50% (NT3), 75% (NT4) and 100% (NT5), 3 replicates for each treatment. The natural seeds (3.08 cm; 1.10 g) were obtained from the supplier in Vinh Chau, Soc Trang province. Fishwere nursed in a 200L plastic tank containing 100 L of seawater at 15 ‰, at 100 ind./m2. After a 30-day nursing period, the results showed that the survival of fish was 77.3-86.4%, no significant difference (P >0.05) was observed when compared between the treatments. The length and weight of fish were improved, but there were no significant differences (P>0.05) observed among the treatments except the weight gain of fish fed the NT2 diet was significantly higher than those fed NT1, and weight gain of fish fed NT5 was significantly lower than those of NT1 diet. The results indicated that the commercial feed could be replaced with Artemiabiomass from 25-75% without any adverse effects on the growth and survival rate of mudskipper fingerlings.

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