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• Evaluation of Apparent Nutrient Digestibility of Diets UsingFish Meal and Catfish By- Product Meal for Guinea Fowls

  Nguyen Dong Hai , Nguyen Thi Kim Dong

  Received: 15-03-2016 / Accepted: 17-08-2016

   Abstract PDF (VIETNAMESE)

  The experiment was carried out to evaluate the apparent nutrient digestibility of Guinea fowls at 8 and 10 weeks of age fed diets containing twodifferent protein feed sources and fourcrude protein (CP) levels. The trial used a completely randomized design with two factors and 3 replications. The first factor was two protein feed sources including fish meal and catfish by- product meal and the second factorcomposed offour dietary crude protein (CP) levels of 16, 18, 20 and 22%. The results showed that the apparent EE, NDF and ADF digestibilities of the diet with fish meal were higher than those of catfish by- product meal diet (P< 0.05). The diets contained 20% CP and 18% CP fed Guinea fowls at 8 and 10 weeks of age had the higher DM, OM, EE, CF, NDF, ADF digestibility coefficients and better N retention (P< 0,05).

• Effect of Culture Conditions on Mycelial Growth of Agaricus blazeiMurill Strain Ab-1

  Tran Thu Ha, Tran Thuy Linh, Nguyen Duy Trinh, Nguyen Van Giang

  Received: 01-03-2022 / Accepted: 27-05-2022

   Abstract PDF (VIETNAMESE)

  Agaricus blazei Murill is a medicinal mushroom with potent immunomodulatory and antitumor activities. Nutrition and environmental conditions are two main factors affecting the mycelial growth of mushrooms. Therefore, the study was carried out to optimize the culture of Agaricus blazei on a pure cultural medium. The carbon sources (glucose, fructose, maltose, sucrose, and lactose), nitrogen sources (NH4Cl, NH4NO3, (NH4)2SO4, NH4HPO4, peptone, and yeast extract) with initial pH values ​​of 4, 5, 6, 7, 8, 9 and incubation temperatures of 15C, 20C, 25C, 30C, and 35C were tested for mycelial growth of Agaricus blazei mushroom strain Ab-1. The mycelial colony diameter, growth rate, and mycelial density were evaluated with P <0.05. Results indicated that glucose and yeast extracts were the most suitable carbon and nitrogen sources for the mycelial growth of strain Ab-1. pH6 and temperature of 25C were also optimal conditions for the growth of Ab-1 mycelia. The mycelial colony's growth rate and diameter reached 8.14 mm/day and 78.44 mm after 10 days.

• Determination of Optimal Culture Conditions for Mycelial Growth of Black Lingzhi (Amauroderma subresinosum) Strain Am-4

  Tran Thu Ha, Nguyen Ham Chi, Nguyen Van Giang

  Received: 15-08-2023 / Accepted: 25-12-2023

   Abstract PDF (VIETNAMESE)

  Black Lingzhi, Amauroderma subresinosumof the the family Ganoderma, contains numerous bioactive compounds, such as sterols, flavonoids, phenols, fatty acids, amino acids, polysaccharides, and triterpenes. Whileactive constituents, distribution, and morphological characteristics of black lingzhi have been studied in Vietnam, there has been limited research conducted to determine the ideal culture conditions that promote mycelial growth. This study aimed to determine the optimal culture conditions for mycelialgrowthof Amauroderma subresinosumstrain Am-4, collected from Bao Lam, Lam Dong province. Strain Am-4 was cultured on Ohta, PDA, SDA, MEA, MCM, and Czapek media under different pH levels, temperatures, carbon, nitrogen, and mineral salt sources. Our results indicated that strain Am-4 exhibited rapid mycelialgrowth on MEA medium at 25°Cand pH5. The strain showed the highest growth rate when cultured in a medium containing glucose and NaNO3as the carbon and nitrogen sources, respectively, with the optimal glucose/NaNO3ratio being 10:1. Additionally, ZnSO4.7H2O was found tobetheoptimal mineral salt source. Under the optimized culture conditions, strain Am-4 exhibited fast mycelial growth with a compact density.

• Using Zooplankton as Bioindicator for Trophic State of Irrigation Canals in Gia Lam, Hanoi

  Nguyen Thi Thu Ha, Ta Thi Hai Yen, Dinh Tien Dung, Do Thuy Nguyen, Trinh Quang Huy

  Received: 08-09-2016 / Accepted: 25-11-2016

   Abstract PDF (VIETNAMESE)

  Zooplankton is not only dependent on the trophic state through food chains of algae but also controls nutrient levels through consumtion of algae. The study was conducted with 16 irrigation canals in the district of Gia Lam that had different nutrient levels to prove the relationship. Many of these irrigation canals were contaminated by various waste sources, showing nutritional status from moderate to high level (60-100 points). From January to May (2015), 71 species of zooplankton were identified with Rotifers being dominant both in number of species (39 species) and density (>70%). The diversity index was moderate at medium trophic level (H' was 2.52 at the TSI of 60-80) and lower in high trophic level (H’ was 1.83 at the TSI of 80-100). The species of lower trophic levels (TN<7 mg/l and TP<0.4 mg/l) included Brachionus budapestinensis, Brachionus falcatus, Brachionus forficula, Keratella tropica(Rotifer); Sida crystallina, andCeriodaphnia quadraugula(Cladoceran). The species adaptable to moderate to high trophic included Ceriodaphnia laticaudata, Alona davidi(Cladocerans); Eucyclops serrulatus, and Ectocyclops phaleratus(copepods). They may be the pollution sensitive and pollution resistant species.