• 수산해양교육연구
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• 제26권4호
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• pp.915-922
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• 2014

This study was conducted to evaluate the optimum dietary protein level in juvenile river puffer. Five semi-purified diets were formulated by using casein to contain graded levels of protein levels of 35, 45, 50, 55 and 65%. Fish averaging $8.56{\pm}0.04g$ were randomly assigned to one of five experimental diets in triplicate groups for 8 weeks. After the 8-weeks of feeding trial, weight gain and feed efficiency of fish fed 45, 50 and 55% diets were significantly higher than those of fish fed 35 and 65% diets (P<0.05). Protein efficiency ratio of fish fed the 35% diet was significantly higher than those of fish fed 65% diet (P<0.05), but there were no significant difference among those of fish fed 45, 50 and 55% diets. Specific growth rate of fish fed 50% diet was significantly higher than those of fish fed 35 and 65% diets (P<0.05), but there was no significant difference among those of fish fed 45, 50 and 55% diets. No significant differences were observed in condition factor, hepatosomatic index, visceralsomatic index and survival among those of fish fed all the diets. Optimum dietary protein levels by using broken-line model and by using second order polynomial were estimated at 45.9% and 51.6% for the maximum growth of fish respectively. Therefore, these results suggested that the optimum dietary protein level could be greater than 45.9% but less than 51.6% for the maximum growth in juvenile river puffer.

• Fisheries and Aquatic Sciences
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• 제17권4호
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• pp.449-454
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• 2014

The effects of food deprivation and feeding ratio on the growth, feed utilization and body composition of juvenile olive flounder Paralichthys olivaceus were investigated in 810 juvenile fish averaging 6.4 g in weight randomly distributed in 27 400-L flow-through tanks. A 3 [food deprivation: 8-week feeding without food deprivation (8W), 7-week feeding after 1-week food deprivation (7W) and 6-week feeding after 2-week food deprivation (6W)]${\time}3$ (feeding ratio: 100%, 95% and 90% of satiation, hereafter denoted by 100, 95 and 90, respectively) factorial design was applied. The weight gain of the fish was significantly affected by both food deprivation and feeding ratio. The weight gain of the fish under the 8W-100 treatment was higher than that of those under the 7W-95, 7W-90, 6W-100, 6W-95 and 6W-90 treatments, but did not differ from those of fish under the 8W-95, 8W-90 and 7W-100 treatments. The specific growth rate (SGR) and the feed intake of the fish were affected by both food deprivation and feeding ratio. However, the feed conversion ratio (FCR) was unaffected by both food deprivation and feeding ratio. The protein efficiency ratio (PER) was affected by the feeding ratio, but not by food deprivation. The protein retention (PR) was affected by food deprivation, but not by feeding ratio. Juvenile olive flounder subjected to 1-week food deprivation at 100% satiation (7W-100 treatment) achieved full compensatory growth.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.632-637
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• 2000

This research was undertaken to restore the biological activity of cyclodextrin glucanotransferase (CGTase) of Bacillus macerans origin expressed as inclusion bodies in recombinant Escherichia coli. The optimum concentration of urea used as a denaturant was 8 M. The supplementation of 0.5 M urea into a dialysis buffer increased the refolding efficiency by preventing any protein aggregation. The influence of the protein concentration, temperature, and pH were also investigated. The protein concentration was found to be the most important factor in the refolding efficiency. The optimum temperature was 15-$25^{\circ}C$ and the optimum pH was 6.0. The maximum specific activity of the CGTase refolded under the optimum conditions was 92.2 U/mg, corresponding to 72% of the native CGTase. A comparison of the secondary structure between the native and the refolded CGTase showed that the relative ratio of the $\alpha$-helix content in the native to the refolded CGTase was 1:0.82.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.318-324
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• 1998

A ${\beta}$-galactosidase with high transgalactosylic activity was purified from a Bacillus species, registered as KFCC10855. The enzyme preparation showed a single protein band corresponding to a molecular mass of 150 kDa on SDS-PAGE and gave a single peak with the estimated molecular mass of 250 kDa on Sephacryl S-300 gel filtration, suggesting that the enzyme is a homodimeric protein. The amino acid and sugar analyses revealed that the enzyme is a glycoprotein, containing 19.2 weight percent of sugar moieties, and is much more abundant in hydrophilic amino acid residues than in hydrophobic residues, the mole ratio being about 2:1. The pI and optimum pH were determined to be 5.0 and 6.0, respectively. Having a temperature optimum at $70^{\circ}C$ for the hydrolysis of lactose, the enzyme showed good thermal stability. The activity of the enzyme preparation was markedly increased by the presence of exogenous Mg (II) and was decreased by the addition of EDTA. Among the metal ions examined, the most severely inhibitory effect was seen with Ag (I) and Hg (II). Further, results of protein modification by various chemical reagents implied that 1 cysteine, 1 histidine, and 2 methionine residues occur in certain critical sites of the enzyme, most likely including the active site. Enzyme kinetic parameters, measured for both hydrolysis and transgalactosylation of lactose, indicated that the enzyme has an excellent catalytic efficiency for formation of the transgalactosylic products in reaction mixtures containing high concentrations of the substrate.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.172-177
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• 2002

This study was conducted to investigate the utilization of Sargassum meal in the diet on juvenile ayu (Plecoglossus altivelis) reared in seawater. White fish meal and wheat flour were used as the dietary protein and carbohydrate sources in the control diet. Wheat flour in the control diet was replaced with $5\%$ and $10\%$ Sargassum meal. Three replicate groups of fish average weighing 4.0 g were fed one of three isonitrogenous$(45\%)$ and isocaloric (14.5 MJ /kg diet) diets for 7 weeks. Survival of all groups were above $80\%$. Weight gain, feed efficiency and protein efficiency ratio were not significantly affected by dietary Sargassum meal levels (P>0.05). There were no significant differences (P>0.05) in moisture, crude protein, crude lipid, crude ash and fatty acid compositions of whole-body fish among groups. It is concluded that Sargassum meal could be used as a dietary additive or alternative low-cost dietary ingredient up to $10\%$ for juvenile ayu reared in seawater.

• 한국식품과학회지
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• 제2권2호
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• pp.1-7
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• 1970

1) 고구마의 경제적 활용과 이유식품의 개발을 목적을 고구마 대두분 및 기타 영양소를 사용하여 단백함량이 20%되는 이유식품을 드럼건조법에 의하여 제조하는 방법을 설정하였다. 2) 이 제품의 단백효율(PER)은 2.63 으로서 고구마 대신 옥수수전분을 사용한 제품의 PER(3.30)보다 낮았는데, 이는 드럼건조중 가용태 라이신의 파괴에 의함을 알았다. 3) 본 이유식품의 전체영양가 (사료효율, 체성분의 조성, 단백질보유율)는 우유식품이나 고구마 대신 옥수수전분을 사용한 이유식품과 비슷하였다.

• 한국수산과학회지
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• 제7권4호
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• pp.209-214
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• 1974

Casein을 단백원으로 하고 조단백질과 지질의 함량을 조사한 사료로서 치무지개송어를 19일간 사육하여 다음과 같은 결과를 얻었다. 1) 무지개송어의 체중은 사료중의 단백질 함량이 많을수록 증가하며 단백질의 함량 $40\%$ 부근에서 최대치에 달하고 그 이상 단백질이 증가하여도 체중은 증가하지 않았다. 체단백질의 증가도 사료중의 단백질 함량이 $40\%$ 부근에서 최대치에 가까워지며 그 이상 단백질이 증가하여 도 변화는 적었다. 2) 단백질의 이용치는 사료중의 단백질 함양이 많을 수록 증가하였으나 체단백질의 축적률은 단백질의 함량 $40\%$ 부근에서 최대치에 달했다. 3) 이상의 결과에서 Casein을 단백원으로 하는 경우 치무지개송어의 단백질 요구량은 사료중 $40\%$라고 생각했다. 4) 사료의 단백효율(y)은 단백질의 함양(x)이 많을 수록 감소하고 그 관계는 y=4.91-0.034x의 방정식으로 표시 할 수 있었다. 5) 사료의 단백질 함량과 사료효율 및 사료계수와의 관계를 검토하였다. 끝으로 시종 실험을 지도하여 주신 동경수산대학에 야진길 교수에게 사의를 표한다.

• 한국식품영양과학회지
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• 제30권3호
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• pp.482-487
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• 2001

To find the possibility in utilizing the fish meat processing by-products, protein nutritional quality and textural properties of crucian carp extraction residue (CCER, feeze dired) incorporated into cookies were investigated. Moisture, ash and protein contents in cookies were increased with the higher residue treatments, but lipid contents were similar within all levels (3%, 9% and 15%). Major constitutional amino acids were revealed as glutamic acid, proline, leucine and arginine, and the sum of those amino acids was about 50% of total amino acid contents. Cookies with residue (CCER) had higher (80.74~84.50%) in vitro protein digestibility than standard cookies (83.32%), while slightly lower trypsin indigestible substrate (TIS) contents were showed in CCER containing cookies than control. CCER treatments resulted the decreased protein nutritional quality in C-PER (computed protein efficiency ratio) value from 2.41 (standard) to 1.15 (cinnamon flavored. 9% CCER), and those C-PER of all cookies were lower than ANRC casein (2.50). Lipophilic browning was developed steadily till 60 days storage and a significant (p<0.05) changes of browning ws not noteed between 60 days and 90 days storage. Color of cookies, expressed as L, a and b value, was significantly (p<0.05) lightened with the increased CCER. Similar trends by treatments were noted for hardness. Cookies containing 9% CCER were similar to control regarding textual and sensory properties.

• Fisheries and Aquatic Sciences
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• 제21권10호
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• pp.30.1-30.6
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• 2018

A study of three feeding trials was conducted to investigate the dietary protein requirements of Pacific white shrimp (Litopenaeus vannamei) at three different growth stages. Six experimental diets were formulated to include increasing protein levels of 25, 30, 35, 40, 45, and 50% (designated as P25, P30, P35, P40, P45, and P50, respectively) for three feeding trials. The three feeding trials were conducted in different-sized shrimp at 0.65 g (trial 1), 4.80 g (trial 2), and 10.5 g (trial 3). Triplicate groups of shrimp were fed one of the experimental diets for 36, 42, and 48 days in trials 1, 2, and 3, respectively. In trial 1, the growth performance was not affected by the dietary protein levels. However, protein efficiency ratio was significantly higher in P30 diet compared to P40, P45, and P50 diets. In trial 2, growth rate was significantly higher in P35 diet than in P25 diet. In trial 3, the lowest growth performance was obtained in P25 diet which significantly differed from that of other experimental diets. Broken line analysis of growth data indicates that the optimal dietary level of crude protein is 34.5, 35.6, and 32.2% for small-, medium-, and large-sized (juvenile, sub-adult, and adult stages) Pacific white shrimp, respectively.

• Fisheries and Aquatic Sciences
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• 제19권5호
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• pp.24.1-24.6
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• 2016

We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of $7.1{\pm}0.06g$ ($mean{\pm}SD$) were randomly distributed into 15 net cages (each size: $60cm{\times}40cm{\times}90cm$, $W{\times}L{\times}H$) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw.