• International Journal of Industrial Entomology and Biomaterials
• /
• 제39권2호
• /
• pp.54-59
• /
• 2019

Yellow mealworms (Tenebrio molitor Linnaeus) are very promising insects for the food and feed industry. Because mealworms are in the spotlight as an alternative protein source in the future, it is necessary to develop efficient rearing techniques for mass production. To evaluate the effects of brewer's yeast (BY) on the growth of mealworms, Tenebrio molitor Linnaeus, the mealworms were fed with wheat bran (WB) diets containing different levels of BY (0, 10, 30, 50, and 70%). Larval survival, larval weight, development time, pupal weight and eclosion rate were monitored for 12 weeks. The results showed that mealworms fed on the diets containing 30% and 50% of BY have significantly higher weight gain, specific growth rate and daily weight gain, and lower larval duration than fed the control diet (100% WB) and other BY diets (10% and 70% BY). Larval survival on the diets containing 30% and 50% of BY was higher than on control diet. Pupal weight and eclosion rate were not significantly different among all diets. In conclusion, we suggest feeding the diet containing 30% of brewer's yeast with wheat bran in order to increase the production of mealworms.

• 한국초등과학교육학회지:초등과학교육
• /
• 제24권2호
• /
• pp.130-137
• /
• 2005

Elementary preservice teachers' understanding about the insect molt and metamorphosis was examined. Data were collected through the paper-pencil test of 448 junior students at a National University of Education. The instrument used was developed by Son(2003) and modified for the test. The results are as follows: First, Only 3.1$\%$ of students had a scientific concept on the molt periods in the insect life cycle. Students had an alternative conception that molt occurs either only in the larval period (29.9$\%$) or only in the period from pupa to adult (22.3$\%$). The percentage of the students thinking that molt occurs in the period from larva to pupa was low. Second, 98$\%$ of students stated that molt has to do with the larval growth, but 39.1$\%$ of students had an alternative conception that molt occurs after the larval growth at each instar. 25.1$\%$ had a conception that molt is related with the larval growth, but did not show any further understanding. Third, most students understood the correct meaning of metamorphosis. 34..2$\%$ of students had an alternative conception that metamorphosis occurs only in the period changing from pupa to adult, and only a few thought that it occurs in the period from larva to pupa. 24.8$\%$ of students had a scientific concept on the periods in which metamorphosis occurs. Fourth, some students understood the hatching process as molt in the sense that the egg shell is taken off (21.0$\%$), and as metamorphosis in terms of the appearance change from egg to larva (25.0$\%$). Fifth, 35.5$\%$ of students selected bees as an insect of incomplete metamorphosis, and 35.3$\%$ responded 'I have no idea', showing that they had poor understanding about the insect life cycle.

• 한국수산과학회지
• /
• 제37권6호
• /
• pp.485-491
• /
• 2004

Spawning induction, egg development and larval growth of ark shell (Tegillarca granosa) (L.) were investigated. The most effective method of spawning induction was steady temperature increasing from$4^{\circ}C\;to\;28^{\circ}C$ with irradiation of sea water by UV after T. granosa was exposed to air at $4^{\circ}C$ Optimum condition for larval roaring was under the 32.4 psu and two temperature $regimes:\;28{\pm}1^{\circ}C\;and \;25{\pm}1^{\circ}C$. Fertilized eggs was demersal isolated eggs, and egg diameter was $60{\mu}$. D-shaped larvae appear about 20 hr after hatching with $94.1{\mu}$ in shell length and $86.7{\mu}$ in shell height. Ten days were required from hatching to umbo larva stage, of a mean shell length $125.2{\mu}$. On 25th day, the larva grew to $450{\mu}$ in shell length and began to settle on the bottom. Effect of temperature between $25^{\circ}C$ (control group) and $28^{\circ}C$ on larval growth was not different. Survival rate of larvae settled on the bottom was about $19{\%}$ in both temperatures conditions $(25^{\circ}C\;and\;28^{\circ}C)$.

• 한국수산과학회지
• /
• 제33권2호
• /
• pp.93-97
• /
• 2000

본 연구는 먹이종류에 따라 고밀도로 배양한 rotifer를 넙치 자어에게 공급하였을 때 이들의 먹이효율을 조사하였다. Rotifer 고밀도 배양의 실험구 먹이는 18 시간 동안 담수산 Chlorella를 공급한 후 6시간 유지효모 및 $Marine\;{\alpha}$를 공급한 것과 24시간 동안 담수산 농축 Chlorella 및 해수산 농축 Chlorella를 공급한 것으로 하였다. 배양수조는 $2l$를 이용하였고 수온 $28{\circ}C$를 유지하였다. $Marine {\alpha}$와 해수산 농축 Chlorella를 공급한 실험구의 n-3 HUFA 함량이 유지효모와 담수산 농축 Chlorella를 공급한 실험구보다 높게 나타났다. 따라서 $Marine\;{\alpha}$와 해수산 농축 Chlorella를 공급한 실험구가 유지효모와 담수산 농축 Chlorella를 공급한 실험구보다 넙치 자어의 성장과 생존률이 높게 나타났다. 또한 $Marine\;{\alpha}$로 배양된 rotifer를 섭취한 넙치 자어 자체의 지방산 중 n-3 HUFA비율이 다른 먹이보다 높게 나타났지만 안정적 배양은 이루어지지 않았다. 따라서 본 실험을 통해서 rotifer 고밀도 배양시 안정적인 rotifer 성장과 rotifer의 질적 개선을 위해서는 24시간 해수산 농축 Chlorella를 공급하는 것이 효율적이며 이들을 넙치 자어에게 공급하였을 때 가장 적절한 먹이일 것으로 판단된다.

• 한국수산과학회지
• /
• 제46권6호
• /
• pp.801-806
• /
• 2013

Spiny lebbeid shrimp Lebbeus groenlandicus larvae were reared in the laboratory to estimate the energy budget from the zoeal to the post-larval stage. Energy expended by larvae on growth and respiration was determined from values for feeding, growth, molting, and metabolism. We calculated that 16.22 J were used for growth throughout all larval stages. Energy loss during molting was estimated as 1.03 J, and energy used for respiration was estimated as 1.31 J. Energy taken in by feeding was estimated as 77.16 J, while the sum of energies expended in excretion and egestion was 58.61 J. Larvae were estimated to assimilate 24.6% of ingested food as energy and to use ~85% of the assimilated energy for somatic growth. Gross growth efficiency ($K_1$) and net growth efficiency ($K_2$) were shown to be ~22% and 93%, respectively. Maintenance costs of respiration were estimated as ~9.7% of assimilated energy.

• 한국수산과학회지
• /
• 제55권5호
• /
• pp.524-532
• /
• 2022

We investigated the effects of taurine-enriched rotifers on larval growth and swim bladder inflation of yellowtail Seriola quinqueradiata. Rotifers were enriched with a commercial taurine supplement at two levels (0 and 800 mg/L). The larvae (initial notochord length=3.98±0.24 mm) were fed the enriched rotifers in triplicate from two days post-hatch for five days. The average taurine contents of the taurine non-enriched and enriched rotifers were 0.35±0.01 and 4.77±0.05 mg/g dry matter, respectively. The weight gain and specific growth rate of the fish fed enriched rotifers with the taurine supplement at 800 mg/L significantly improved compared with those of fish fed rotifers without taurine enrichment (P<0.05). The swim bladder inflation rate of larvae fed taurine enriched rotifers significantly (P<0.05). The results of the present study indicate that yellowtail larvae benefit from taurine concentrations compared with those typically reported to feed on non-taurine supplemented rotifers. Furthermore, taurine-enriched food for fish larval effectively improved the growth performance and swim bladder inflation of yellowtail larvae.

• 한국패류학회지
• /
• 제19권1호
• /
• pp.33-40
• /
• 2003

To obtain the basic information on culture conditions for the larvae of Saxidomus purpuratus, experiments were conducted on the population from southern coast for (1) the success in fertilization and development from artificial fertilization among different months of a year, (2) the viability of sperms after exposure to seawater, (3) and the effects of temperature, salinity, and food organism on the survival and growth of larvae. Gametes obtained from dissection showed high rate of fertilization at all months. But the rate of development was higher only May-July. Developmental success seemed to be related with the quality of eggs at the time of fertilization. Developmental times for 2-cell, 4-cell, 8-cell, blastula, trochophore larva, and veliger larva at 20$^{\circ}C$ were 1.5, 2, 4, 18, 24, and 32 hr, respectively. Sperms could survive for more than 8 hr, however, actively swimming sperms could be found within 1 hr after exposure to seawater. It is recommended that sperms should be used for fertilization as soon as possible when they are exposed to seawater. At temperature of 35$^{\circ}C$, all the larvae died during 48 hr. Larval survival decreased when salinity was either lower than 20 psu or higher than 40 psu, and was 0% when salinity was 10 psu. Optimal range of temperature and salinity for rearing larvae of S. purpuratus were 20-25$^{\circ}C$ and 20-40 psu, respectively. Larvae grew from 111.5 to 235.3 ${\mu}$m during 21 days. Larvae fed mixed diets grew faster than unialgal diets. The fastest growth was observed when larvae were fed on the mixture of Isochrysis galbana and Nannochloris oculata.

• 한국수산과학회지
• /
• 제53권4호
• /
• pp.530-537
• /
• 2020

This study compared the survival rates, growth, and fatty acid content of larval Pacific cod Gadus macrocephalus fed with rotifers raised on different enrichment diets. We used four commercial rotifer enrichment products (one domestic, ER1, and three imported, ER2, ER3 and ER4). Twelve 200-L tanks were used, with three replicates per treatment. Larvae were fed rotifers 3 times daily at a rate of 5 rotifers/ml/feeding from 7 to 21 days post-hatch. At the end of the feeding trial, the survival rate and total length of larvae fed ER3 were greater than those of larvae fed ER1, ER2, or ER4. ER3 had the highest proportions of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and polyunsaturated acid (PUFA). Partially reflecting this composition, larvae fed ER3 had the highest proportions of DHA and PUFA. These results show a positive effect of rotifer DHA and PUFA proportions on the survival and growth rates of Pacific cod larvae.

• 한국양식학회지
• /
• 제8권1호
• /
• pp.69-76
• /
• 1995

넙치(Paralichthys olivaceus) 암컷과 범가자미(Verasper variegatus) 수컷간의 잡종을 유도하여 넙치, 범가자미 및 잡종을 대상으로 변태기 전인 부화후 25일째까지 자어의 생존율 및 성장을 비교 조사하였다. 실험 종료시 잡종의 생존율과 성장은 양친으로 사용된 두 종 중 넙치와 유사하였다(P>0.05). 부화자어의 형태에서 잡종은 난황의 길이 대 폭의 비에서 넙치와 좀 더 많이 닮았고, 수온 $17\pm1^{\circ}C$에서 유구가 완전히 소실되는 기간은 잡종이 18일, 넙치가 14일이었으며 범가자미에서는 유구가 관찰되지 않았다. 조사 결과 변태기전까지의 잡종은 그의 생존율 및 성장에서 범가자미 보다 넙치와 더 유사한 경향을 나타내었다(P>0.05).

• International Journal of Industrial Entomology and Biomaterials
• /
• 제32권1호
• /
• pp.41-48
• /
• 2016

Mealworms, Tenebrio molitor (Coleoptera: Tenebrionidae), are widely used as food sourcefor animal rearing as well as human diet. Conventionally, mealworms raised on wheat bran. In this study, we investigated the effects of brewer's spent grain (BSG) on the growth of mealworm larvae to reduce the rearing cost. We prepared five different diets with various BSG content, 0, 10, 30, 50, and 70% of heated air dried BSG with wheat bran. We compared survivorship, larval weight, developmental duration, pupation rate, and pupal weight of five different groups of T. molitor raised on these five diets. The larval survivorships were almost similar with the control group except a group with 70% of BSG. For the larval weight, groups with 30% and 50% of BSG gained more weight than that with control treatment, 0% of BSG. For the developmental period, the groups with 30% of BSG took less time compared to the control group. In all treatment groups, more than 90% of pupation rate were observed. Especially, the group with 30% of BSG showed highest pupation rate among the five groups. Wheat bran with 30~50% of BSG was the optimal diet for successive insect rearing among the five diet treatments. Based on this study, we concluded that adding BSG to wheat bran helps to improve the quality of T. molitor and to reduce the rearing period.