• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.37 no.1
• /
• pp.7-12
• /
• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.5
• /
• pp.665-673
• /
• 2012

A balance trial experiment was carried out to evaluate the potential relationship between an enzymatically hydrolyzed yeast (EHY) and yeast culture combined with a live Bacillus subtilis (Bs) on the productive parameters, ileal digestibility, retention of nutrient and energy and villus morphology in broilers. Seventy two 28 d old, Ross B308 male broilers were assigned to a factorial combination of 2 levels of EHY (0 and 1 kg/ton of feed) and 2 levels of Bs (0 and 125 g/ton of feed). The experiment lasted 2 weeks. Several treatment interactions were observed. EHY-fed broilers showed the lowest feed intake and feed conversion ratio whereas Bs-fed broilers showed the highest feed intake and intermediate feed conversion ratio (EHY and BS interaction, p<0.05). Also, EHY-fed broilers had greater ileal digestibility of dry matter (EHY and BS interaction, p<0.01) and energy (EHY and BS interaction, p<0.05) but these responses were counterbalanced by the combination of EHY and Bs. The thickness of the mucosa was similar between the control and EHY-fed broilers, but was lowest when Bs was added alone (EHY and BS interaction, p<0.01). The thickness of the villus was greater in EHY plus Bs-fed broilers, intermediate for the control and lower for Bs or EHY-fed broilers (EHY and BS interaction, p<0.05). The area of the villus was greater in the control and EHY plus Bs-fed broilers (EHY and BS interaction, p<0.05). In addition, EHY-fed broilers showed greater breast yield and nitrogen retention (p<0.01) and ashes digestibility (p<0.05). On the other hand, Bs-fed broilers had greater carcass and breast weight, nitrogen retention, energy excretion and villus height (p<0.05). In summary, EHY and Bs enhanced some growth, carcass and nutrient retention responses, but did not show any synergic relationship in these responses. Opposite to this, the results suggest that the positive effect of EHY on the feed conversion and digestibility of nutrients were counterbalanced by the addition of Bs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.6
• /
• pp.606-613
• /
• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• Journal of the Korean Society of Food Culture
• /
• v.25 no.2
• /
• pp.207-215
• /
• 2010

The purpose of this study was to investigate the microbiological characteristics and antioxidant activity of tomato sauce in terms of the variety of herbs that have been widely used in Western cuisine. As storage time increases, the number of total microbes changes, but the bacteria count was in the range of $1.0{\times}10^1-2.1{\times}10^2$, which did not increase much over 60 days of storage. The reason seems to be that the amount of heat treatment undergone by this type of sauce type, and its acidity make for difficult conditions for microbes to live. Yeast and mold measurements showed that yeast and mold were not detected for up to 30 days of storage in the tomato sauce with various types and amounts of added herbs. After 45 and 60 days, the yeast and mold count was in the range of $1.0{\times}10^1-8.5{\times}10^1$, and the same in the control. Measurements of phenolic compounds in 60 days of storage showed that tomato sauce with different types and amounts of added herbs had the lowest amounts relative to the control for all storage periods. The more herbs that were added, the higher the phenolic compounds resulted. As storage times increase, the phenolic compounds showed a tendency to decline. The DPPH radical scavenging effects of the tomato sauce herbs added showed a tendency to increase antioxidant activity when more herbs were added. The microbiology results of the storage test of tomato sauce with added herbs showed that the amount of microorganisms in tomato sauce with added herbs did not increase much in 60 days of storage at $4^{\circ}C$. The amount of microorganisms was small, so tomato sauce with added herbs can be used for 2 months with refrigeration.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.2
• /
• pp.211-218
• /
• 2016

This study evaluated the effect of Candida norvegensis (C. norvegensis) viable yeast culture on in vitro ruminal fermentation of oat straw. Ruminal fluid was mixed with buffer solution (1:2) and anaerobically incubated with or without yeast at $39^{\circ}C$ for 0, 4, 8, 16, and 24 h. A fully randomized design was used. There was a decrease in lactic acid (quadratic, p = 0.01), pH, (quadratic, p = 0.02), and yeasts counts (linear, p<0.01) across fermentation times. However, in vitro dry matter disappearance (IVDMD) and ammonia-N increased across fermentation times (quadratic; p<0.01 and p<0.02, respectively). Addition of yeast cells caused a decrease in pH values compared over all fermentation times (p<0.01), and lactic acid decreased at 12 h (p = 0.05). Meanwhile, yeast counts increased (p = 0.01) at 12 h. C. norvegensis increased ammonia-N at 4, 8, 12, and 24 h (p<0.01), and IVDMD of oat straw increased at 8, 12, and 24 h (p<0.01) of fermentation. Yeast cells increased acetate (p<0.01), propionate (p<0.03), and butyrate (p<0.03) at 8 h, while valeriate and isovaleriate increased at 8, 12, and 24 h (p<0.01). The yeast did not affect cellulolytic bacteria (p = 0.05), but cellulolytic fungi increased at 4 and 8 h (p<0.01), whereas production of methane decreased (p<0.01) at 8 h. It is concluded that addition of C. norvegensis to in vitro oat straw fermentation increased ruminal fermentation parameters as well as microbial growth with reduction of methane production. Additionally, yeast inoculum also improved IVDMD.

• Korean Journal of Poultry Science
• /
• v.29 no.3
• /
• pp.205-211
• /
• 2002

A feeding trial was conducted to study the effects of a live yeast, Pichia farinosa culture(PF), on the production performance and intestinal microflora in laying hens. One hundred and sixty ISA Brown layers, 21 weeks of age, were randomly allotted to four dietary treatments, with four replicates per treatment. Dietary treatments consisted of four levels (0, 0.1, 0.3, and 0.5%) of PF added to a com-soybean meal based diet. Egg production, egg weight, feed intake and fred conversion ratio(FCR) were measured. Egg qualifies were examined at 25th and 29th weeks of age. A metabolism trial was conducted following the feeding trial, during which intestinal microflora, nutrient digestibility and fecal NH3 gas emission were measured. Egg production of birds fed 0.1 and 0.3% PF were significantly higher than those from birds fed 0 and 0.5% PF(P<0.05). Daily egg mass of 0.3% PF increased significantly compared to that of 0% PF. There was no difference in egg weight among all treatments. Feed conversion ratio was significantly improved as the PF level increased. No significant difference was found in eggshell quality and Haugh unit at both 25 and 29 weeks of age. Viable count of ileal Lactobacillus spp. increased significantly as the rf level increased. However, the total number of yeast and anaerobes in ileum were similar among all treatments. Cecal Lactobacillus spp. and yeast counts showed no difference among all treatments. Fecal NH$_{3}$ gas emission of layers fed PF decreased significantly by the PF supplementation. From the result of this experiment, it could be concluded that dietary supplementation of the live yeast Pichia farinosa improves the laying performance and decreases the fecal ammonia gas emission.

• Journal of Microbiology
• /
• v.44 no.4
• /
• pp.439-446
• /
• 2006

In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates $(0.05 h^{-1}\;to\;0.40h^{-1})$ using a 2L stirred tank fermenter with a working volume of 600ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, ${\mu}_{max}$, was estimated at $0.40h^{-1}$I, and the Monod cell growth saturation constant, Ks, at approximately 0.25g/L. Maximum cell viability $(1.3{\times}10^{10}CFU/ml)$ was achieved in the dilution rate range of $D=0.28h^{-1}\;to\;0.35h^{-1}$. Both maximum viable cell yield and productivity were achieved at $D=0.35h^{-1}$. The continuous cultivation of L. rhamnosus at $D=0.35h^{-1}$ resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.2
• /
• pp.164-170
• /
• 2000

This study was carried out to investigate the effect of photosynthetic bacteria to chlorella or ${\omega}-yeast$ on Browth of the rotifer and its dietary value for flounder, Paralicbthys oliraceus. The rotifer fed the chlorella (200,000 cells/ind./day) with the addition of 20 times the photosynthetic bacteria of the chlorella concentration showed the highest growth. But the specific growth rate of 100,000 chlorella/ind./day with the addition of 30 times the photosynthetic bacteria was the most economical feeding regime for mass culture of the rotifer. The rotifer frd ${\omega}-yeast$ with 200,000 cells/ind./days with the addition of 20 times the photosynthetic bacteria of the chlorella conecentration showed the highest growth. Growth and survial rate of the larvae of Paralichithys oiivaceus fed the rotifer reared on both chlorella and ${\omega}-yeast$ with the addition of photosynthetic bacteria were higher than those without the bacteria, and the chlorella had better dietary value than the ${\omega}-yeast$ for the larvae. The larvae fed the rotifer which was cultured with the chlorella of 200,000 cells/ind./day and the photosynthetic bacteria of $4{\times}10^6$ cells/ind./day showed the highest survial rate and growth. The larvae reared with the addition of the photosynthetic bacteris had higher total lipid and the total content of EPA and DHA than those reared without the bacteria. The larvae fed the enriched artemia nauplius with the photosynthetic bacteria also showed higher suurval rate and growth than those fed the nauplius without the enrichment. The optimum enrichment concentration of the photosynthetic bacteria for artemia nauplius was $2{\times}1^7\;cells/ml$. The addition of the photosynthetic bacteria to the chlorella and the ${\omega}-yeast$ was effective to growth of the rotifer and dietary value for the flounder larvae. However, an excessive addition of the bacteria decreased both the growth of the rotifer and the dietary of the larvae.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.1
• /
• pp.30-37
• /
• 2016

Microalgae are functional foods because they contain special anti-aging inhibitors and other functional components, such as ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and omega-3 polyunsaturated fatty acids. Many of these functional dietary components are absent in animals and terrestrial plants. Thus, microalgae are widely utilized in human functional foods and in the feed provided to farmed fish and terrestrial livestock. Many marine organisms consume microalgae, often because they are in an appropriate portion of the cell size spectrum, but also because of their nutritional content. The nutritional requirements of marine organisms differ from those of terrestrial animals. After hatching, marine animals need small live forage species that have high omega-3 polyunsaturated fatty acid contents, including EPA and DHA. Euglena cells have both plant and animal characteristics; they are motile, elliptical in shape, 15-500 μm in diameter, and have a valuable nutritional content. Mixotrophic cell cultivation provided the best growth rates and nutritional content. Diverse carbon (fructose, lactose, glucose, maltose and sucrose) and nitrogen (tryptone, peptone, yeast extract, urea and sodium glutamate) supported the growth of microalgae with high lipid contents. We found that the best carbon and nitrogen sources for the production of high quality Euglena cells were glucose (10 g L^–1) and sodium glutamate (1.0 g L^–1), respectively.

• Journal of Aquaculture
• /
• v.18 no.1
• /
• pp.52-59
• /
• 2005

The productivity of cyclopoid copepod, Apocyclops royi fed by various diets (Isochrysis galbana, Tetraselmis suecica, Phaeodactylum tricornutum, concentrated freshwater Chlorella and baker's yeast) was investigated at tile different temperatures ($16-36^{\circ}C$) with different salinities (5-34 ppt). A. royi was cultured in 6 ml vessels (12 wells culture plate). Total production (188 inds.) and daily production (13.4 inds.) of nauplii by A. royi female at $32^{\circ}C$ were significantly higher than those of nauplii at the different temperatures (P<0.05). Development time from nauplii to copepodite and from nauplii to adult tended to increase with increasing water temperature up to 32. And total production (169 inds.) and daily production (9 inds.) of nauplii by A. royi female at 10 ppt were significantly higher than those of nauplii at the different salinities (P<0.05). The fastest development time from nauplii to copepodite and from nauplii to adult was observed at 10 ppt and 15 ppt, respectively (P<0.05). The highest total production of A. royi nauplii and fastest development time from nauplii to adult were obtained in females fed Isochrysis galbana (P<0.05). These results may indicate that the optimum culture temperature and salinity for A. royi are $32^{\circ}C$ and 10 ppt, respectively, and Isochrysis galbana is one of the suitable diets for this copepod.