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Tang Tri Hung
“ Primarily evaluation of domestication results of giant freshwater prawn (Macrobrachium rosenbergii De Man)”
Thesis was carried out from September, 1999 to August, 2001 in Research center for Shrimp of Vungtau and Tieucan district, Travinh province. The primary results determined Thailand strain to be good ability to resistant and grow on practical Vietnam environment. These were addressed some indicators below:
The broodstock was good able to adapt on new Vietnam environment. Numbers of larvae per gram of females from Thailand were 486 and from Vietnam were 501. The survival of larvae from Thailand to Post-larvae (PLs) was 53.5% and from Vietnam was 28,6%.
The PLs from Thailand were grow-out in semi-intensive system, household condition, were excellent growing and yielding 1,587 kg/ha/crop (7 months) and from Vietnam was 852 kg/ha/crop.
In condition of stocking maturation in cement tank, Numbers of larvae per gram of F1 generation female from Thailand were 628 that achieved standard of producing seed and from Vietnam were 923.
Index of larvae stages and total time for metamorphosis from Thailand were shorted than larvae from Vietnam, living same environment. The survival of larvae to PLs and the ability of producing Pls per liter of larvae from Thailand were 54.2% and 44.5 PLs. These indicated significant differences to larvae from Vietnam were 30.5% and 24.4 PLs/L.
Trials of producing seed following procedure of clear open water system at different scale with rearing density 80 ind / l, obtained 46.6% survival Pls in 0.1 m3, 32.6% in 2 m3 volume and 30.7% in 6 m3 volume.
Tran Kim Hang
"The status of the aquaculture of tropical clam Meretrix lyrata - The remaining problems and recommendations for development in the coastal Tien Giang and Ben Tre"
The Thesis was carried out in the clam culture area in Tan Thanh village, Go Cong Dong district, Tien Giang province and Bao Thuan village, Ba Tri district, Ben Tre province. The project was conducted in 2001.
The results show that the aquaculture of clam Meretrix lyrata depends largely on the natural seed resource and physical conditions of the culture areas. Although water quality has temporal and spacial variations but it still lie on allowable limit for the development of clam and safe level of food sanitation. The potential area for clam culture still remains very large.
The popular form of clam culture is co-orperative culture among farmers, which occupy 74.3% in Tan Thanh and 98% in Bao Thuan. The stocking seeds in Tan Thanh are usually small, after a certain culture period, farmers partially harvest clam to reduce density of clam due to the increase in clam's biomass. The amount of clam harvested at this stages was sold to other farmers or transfer to other culture areas for continuing to culture to commercial sizes.
The productivity achieved at 21.5 tons/ha in Tan Thanh and 20.78 tons/ha in Bao Thuan. The commercial sizes for exporting via processing enterprises are 110 individuals/kg and the local consumed commercial sizes are 30 - 80 individuals/kg.
The income from clam culture is quite high in comparision with other careers in coastal areas. The profit obtained from clam culture in self/personal culture form was highest (1.61times of total money invested) but the co-orperative (1.57 times of total money invested) was most effective in term of culture time/ crop.
With current level of culture technique and scale, the culture area/household should not be enlarged but it is necessary to paid more attention on technique, management experience and money invested…
Income distribution among farmers shows strong inequity via Gini's ratio = 0.59 in Tan Thanh and 0.76 in Bao Thuan, due to differences in quality of culture areas, management experiences and culture techniques…
The aquaculture of clam contribute largely on the poverty elimination, however, unfavourable weather, disseminatoin of pathogens sometimes lead to the mass death of clam, or problems with outlet, those may cause high loss for farmers.
The government has been step by step involved in this type of aquaculture but the farmers still have difficulties on outlet, capital, the lack of information on price…
This project also gave some suggestions to the sustainable development of the aquaculture of tropical clam Meretrix lyrata.
Tran Trong Chon
This report was carried out on collection of analysing farmer‘ data (140/ 468 householdls) in order to investigate the development of intergrated rice - shrimp farming system in Binh Khanh village - Can Gio district - Ho Chi Minh City. From information based on questionaire survey, we analyzed to understand and identify problem in social, technical and economic aspect. Then, we estimated the value of economic reslult.
The result of this research consisted of:
* Social - economic aspect: source of households‘ labors were abundant. Majority of farmers had one crop rice culture, so their living level was low before having intergrated rice - shrimp system.
* Technical aspect: because of farmer‘s limited education, they were difficult to learn new technique. Farmers applied rice - shrimp culture system from folklore experience and neighbor’s knowledge.
* Economic effects : with application of intergrate rice - shrimp system in Binh Khanh village, the household could receive shirmp yield 432 kg/ha/crop. Average profit of this system was 12.477.290 Vietnam dong per hectare and average income per hectare was 13.791.320 VN dong. Cost efficiencies from shirmp culture system were sixteenhold more than rice culture.
* Developmental potency: Binh Khanh village has suitable natural condition and enviroment for sustainable development of this activity.
Trinh Thi Kim Chi
“Trial on using rubber oilcake in diets for hybrid catfish (Clarias gariepinus x C. macrocephalus)”
included 2 experiments carried out in the Experimental Station of the Fishery Faculty in University of Agriculture and Forestry, HCMC, from 12/9/2001 to 01/4/2002. Each of them lasted for 56 days and included 6 diets (treatments) containing 25% crude protein and 16.5 kJ/g gross energy. A Completely Randomized Design with triplicates per treatment was used in every experiment.
* The first experiment was carried out to evaluate rubber oilcake using (ROC) in diets of hybrid catfish. Six diets (T0 to T5) were formulated to contain different inclusion levels of 0, 10, 20, 30, 40, 50% ROC of dry matter (DM), respectively.
- Growth performance (WG, DWG, PWG, SGR) and the feeding efficiency (FCR, PER, NPU) of hybrid catfish were influenced by inclusion rate of ROC in diets.
- There were not statistically significant differences for survival rates; the chemical composition of carcass of hybrid catfish (moisture, protein, ash), hepato-somatic and adiposesomatic index among the treatments (P > 0.05).
- There was not any statistically significant difference between T0 and T1 for growth performances; survival rates; feeding utility efficiency; the chemical composition of carcass; hepato-somatic and adiposesomatic index of hybrid catfish (P > 0.05).
- The cost of feed per kg of weight gain from T0 to T5 were 6,268; 6,074; 6,059; 5,683; 5,890 and 6,984 VNÑ, respectively. The cost was highest in T5 and lowest in T3, however, on the side of weight gain it may be concluded that T-1 was the economical optimum.
* The second experiment was carried out to improve the ROC utilization by hybrid catfish supplementing of lysine, methionine and di-calciphosphate at 0.5; 0.5 and 1% of DM in diets, respectively. Six diets (T-20, T20+ to T40+) were formulated to contain different contents of ROC; lysine, methionine and di-calciphosphate, with T20 was the control treatment (no supplied EAA + Ca, P)
- There were not statistically significant differences for survival rates; the chemical composition of carcass of hybrid catfish (moisture; Ca, P concentration); hepato-somatic and adipose-somatic index among the treatments (P > 0.05)
- Growth performance (WG, DWG, PWG, SGR) and the feeding efficiency (FCR, PER, NPU) of hybrid catfish were improved by supplementing lysine, methionine and di-calciphosphate. T20+, T25+ were the dominant treatments and there was not any statistically significant difference between T20+ and T25+ (P > 0.05)
- The cost of feed per kg of weight gain from T20 to T40+ were 10,265; 7,977; 8,327; 9,424; 9,075 and 9,528 VNÑ, respectively. Therefore, it may be concluded that T20+ and T25+ were the economical optimum diets.
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Last modify: 12-09-2008
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