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Blue swimming crab, broodstock, formulated diets, growth performance, amaranth extracts
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Efrizal E, Syam Z, Rusnam R and Suryati S. Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.12688/f1000research.20029.1)
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Research Article
Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts
[version 1; peer review: 2 approved with reservations]
PUBLISHED 19 Aug 2019
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Abstract
Corresponding author:
Efrizal Efrizal
Competing interests:
No competing interests were disclosed.
Grant information:
This study was supported by a research grant from the Faculty of Math and Science, Andalas University (No. 17/UN.16.03.D/PP/FMIPA/2019) and “Percepatan Guru Besar” from the Research and Community Service Institution, Andalas University (No. T/49./UN.16.17/PP.OK-KRP2GB/LPPM/2019).
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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© 2019 Efrizal E et al.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
How to cite: Efrizal E, Syam Z, Rusnam R and Suryati S. Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.12688/f1000research.20029.1)
First published: 19 Aug 2019, 8:1466 (https://doi.org/10.12688/f1000research.20029.1)
Latest published: 19 Aug 2019, 8:1466 (https://doi.org/10.12688/f1000research.20029.1)
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Introduction
The waters of the province of West Sumatra provide a water marine area that includes the Indonesian Exclusive Economic Zone, which encompasses approximately 186,580 km2, with a long coastline of 2420.387 km, and provides habitat for many biological natural resources1. This marine area, when used wisely, from planning to the administration, implementation, and supervision, will support the welfare of people along the coast in general and the coast of Indonesia in particular. The crab (Portunus pelagicus) belongs to the Portunidae family, is a marine biota resource. It has great potential to become an important fishery export commodity2–6, since in recent years, domestic and international demand has increased from year to year7,8. According to data from the last ten years for the period 1993–2002, the export volume of crabs increased by an average of 16.72% per year, from 6,081 tons in 1993 to 11,246 tons in 20021, whereas in the period 2007–2009 reports on the Indonesian market share of crab decreased from 17.6% to 16.3%9. The intensive harvest of crabs could cause a decline in natural populations of crabs10. Because little control exists in crab harvesting, populations of crabs are rare in Indonesian waters11. Until now the demand for crabs, for domestic consumption and for export, has still relied on the catch from the sea, so this concern will affect the crab population in nature12.
An increase in P. pelagicus production can be achieved in an intensive aquaculture system. Aquaculture is one of the ways to address the threat of crab population decline from overexploitation13–16. The business of crab farming is still in its early phase in Indonesia and in many countries in the world17. Some researchers have reported that a low growth performance and the survival rate remain as problems in culture of the blue swimming crab17, which is caused by various factors, such as disease18–20, molting syndrome21, cannibalism22, and feed3,7,8. Feed is the main component needed by the crab to survive and grow. The completeness of nutrients in the feed is absolutely necessary to ensure the normal growth of the crabs. Nutritional requirements for crab growth, including proteins, fats, carbohydrates, vitamins, and minerals, differ by crab type and size3,8,23, with advantages being provided from formulated feeds over the live feeds (fresh feed)24.
One important breakthrough in the cultivation of softshell crabs, which has been developed by Fujaya25, is the discovery of a molting stimulant derived from amaranth plant extract (Amaranthacea tricolor) called vitomolt. Amaranth extract containing ecdysteroids and application through injection proved to accelerate molting and did not cause death in the crabs; furthermore, the growth of crabs that received the application of amaranth extract was greater than that of the crabs that did not. Based on the description given above, an in-depth assessment of the effects of the feeding of amaranth extracts in varying doses on the quality of formulated diets for growth performance and survival rate of P. pelagicus (Linnaeus, 1758) was needed. Therefore, this study was conducted.
Methods
The study was conducted from January until June 2019 at Balai Benih Ikan Pantai (BBIP) Teluk Buo, Balai Benih Ikan (BBI) Bungus, in the city of Padang and at the Laboratory of Animal Physiology Department of Biology, Padang, West Sumatra.
Ethical considerations
In recent years, the production of crabs has decreased both in number and size. While Blue Swimming crab (Portunus pelagicus) is classified as vulnerable to endangered in the Indonesian marine waters, the Government of the Republic of Indonesia does not require licenses to be obtain to capture and rear this species (Regulation of the Minister of Environment and Forestry of the Republic of Indonesia No: P.92/MENLHK/SETJEN/KUM.1/8/2018; https://www.jalaksuren.net/wp-content/uploads/2018/10/Permen-LHK-P.92-2018.pdf), hence no licenses are applicable to this study. No animals suffered as a result of the activities of this study. P. pelagicus was transported to the hatchery for rearing and at the end of the experiment P. pelagicus remained in good condition.
Crab collection and husbandry
In total 70 female crab samples were collected on January 2019; 20 were females at stage II of ovarian maturity, which were selected for this study2. The female crab samples were collected from the coastal region of Padang (100° 22’12” BT, 1° 0’ 54” LS dan 100° 25’58,8” BT, 1° 4’ 40,8” LS), West Sumatra, and the crabs were placed randomly in four concrete tanks (200 cm × 100 cm × 100 cm), each divided into five units, i.e., plastic boxes (45.5 cm × 32.5 cm × 16.5 cm), where the crabs were held at a maximum density of one crab per box. Tanks were provided with approximately a 15-cm-thick layer of sand for substrate and with adequate aeration2,7,8,26–28. The crabs were maintained in monitored water with a water depth of 25 to 30 cm, salinity of 30 to 32 ppt, pH 7.77 to 7.96, temperature 26 to 27°C, and dissolved oxygen (DO) 7.00 to 7.30 ppm. Each crab was provided with a shelter made of PVC pipe, 13 cm in diameter and 40 cm in length, to serve as a refuge during molting. Dietary Vitamin E was fed daily at 3% biomass (17.00 to 18.00 hours), and uneaten food was removed every morning.
Feed intervention
The method used in this study was a completely randomized design (CRD) with four treatments and five replications of amaranth extract-enriched diets, with treatments as follows: Fdiet 1, formulated diet without amaranth extract 0 ng/g crab; Fdiet 2, formulated diet enriched with amaranth extract at 250 ng/g crab; Fdiet 3, formulated diet enriched with amaranth extract at 500 ng/g crab; and Fdiet 4, formulated diet enriched with amaranth extract at 750 ng/g crab. The formulated diet3,7,29 was a modified formulation of one used for the broodstock of mud crab Scylla serrata16. Amaranth extract was dissolved in 80% ethanol in a ratio of 1:1 and then homogenized. Then, the 80% ethanol solution was added at a rate of 20 mL/kg of feed by even spraying of the solution onto the test feed, and the feed was then left to dry. The test feed was stored until it was ready for use30.
Prior to receiving artificial feed, the broodstock was first given a natural feed (fresh bivalve molluska + sardinella fish; 1: 1) and gradually acclimatized with artificial feed for 10 days. Feed was given at a dose of 8–10% of biomass per day for natural feed and 3–4% for artificial feed. The feed was given three times a day at 08.00, 13.00 and 17.00, with a percentage of 40% in the morning and the remainder being divided into two periods: the afternoon and evening. The remaining food was discarded every morning, and the amount of food was adjusted to the weight of the crab mother at the time of observation. The number of dead crabs were observed and recorded daily.
Variables assessed
Measured parameters (absolute weight gain, absolute carapace length, absolute carapace width and survival rate) and water quality refer to Efrizal et al.7. The absolute weight gain was calculated as follows: AWG = WGf – WGo, where AWG is weight gain (g), WGf is the weight of the crab at the end of experiment (g), and WGo is the weight of crab at the start of experiment (g). The absolute carapace length was calculated as follows: ACL = CLf – CLo, where ACL is carapace length gain (mm), CLf is the carapace length of the crab at the end of experiment (mm), and CLo is the carapace length of crab at the start of experiment (mm). The absolute carapace width was calculated as follows: ACW = CWf – CWo, where ACW is carapace width gain (mm), CWf is the carapace width of the crab at the end of experiment (mm), and CWo is the carapace width of crab at the start of experiment (mm). The carapace length, carapace width, and survival rates were measured as described previously2,3,31. Weights were measured to 0.01 g on the electronic balances (BL3200H-SHIMADZU).
The water quality parameters that were monitored daily were temperature (°C), salinity (ppt), pH, and water depth (cm) while dissolved oxygen (ppm) and CO2 (ppm) thrice weekly using a maximum-minimum thermometer, hand-held Atago refractometer model 8808, Thermo Orion Benctop pH meter models 410 A plus, weighted line, YSI oxygen meter model 57, and APHA32, respectively.
Statistical analysis
The data for growth performance (absolute weight gain, absolute carapace length, and absolute carapace width) and survival rate7 were analyzed using one-way ANOVA and Duncan’s Multiple Range test to compare the differences among the means of the different treatments33 were performed using SPSS software (version 19.0 for Windows; SPSS Inc., Chicago, II. Arcsine transformation was performed before the data, in percentages, was analyzed.
Results
Absolute weight gain
The growth measure of absolute weight is a measure of the weight difference observed in a female crab for a certain time when weighed at the beginning and end of the period. The observation of the average weight and absolute weight gain in the female parent crab P. pelagicus (Linnaeus, 1758) with different dietary treatments is presented in Table 1. Table 1 shows that the growth tends to increase the absolute weight of the maintenance period for 0 to 40 days. From the weighing results (Table 1), the highest absolute value of the average weight obtained in the administration was achieved with Fdiet 3 (55.03 g), followed by Fdiet 4 (18.05 g), Fdiet 1 (32.49 g), and Fdiet 2 (42.49 g); analysis of variance showed significant differences (P < 0.05). Duncan's test showed further significant differences (P < 0.05), which can be observed between the treatments Fdiet 3 and Fdiet 1 and between Fdiet 3 and Fdiet 4, whereas no significant differences (P > 0.05) were observed between Fdiet 3 and Fdiet 2, and between Fdiet 1 and Fdiet 4. The relationship between the amaranth-extract doses in the formulated diet and the absolute weight gain is presented in Figure 1. The regression equation is AWG = -0.0002DAE + 0.1274DAE + 29.816 (R² = 0.4155; P < 0.05).
Table 1. Average weight (g) and absolute weight gain (g) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock fed a formulated diet containing amaranth extracts at different doses.
Values are means ± standard errors (SE). AWG, absolute weight gain; Fdiet 1, formulated diet without amaranth extract 0 ng/g crab; Fdiet 2, formulated diet enriched with amaranth extract 250 ng/g crab; Fdiet 3, formulated diet enriched with amaranth extract 500 ng/g crab; and Fdiet 4, formulated diet enriched with amaranth extract 750 ng/g crab.
Figure 1. The relationship between the dose of amaranth extracts (DAE) in a formulated diet and the absolute weight gain (g) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock.
Absolute carapace length
Absolute carapace length is calculated from the difference in the size of the parent crab carapace length achieved within a certain time, when the carapace length is measured at the beginning and end of the period. Treatment with the different diets caused relatively large changes in the growth of the absolute carapace length during the maintenance period for the 40 days, ranging from 1.22 to 7.09 mm (Table 2), with analysis of variance showing significant differences (P < 0.05). Based on the data in Table 2, the accretion of the greatest absolute carapace length was obtained with the treatment Fdiet 3 (7.09 mm) in comparison with the treatment Fdiet 4 (1.22 mm), Fdiet 1 (3.60 mm) and Fdiet 2 (4.61 mm). Similarly, the results of a further test for significant differences (P < 0.05) with Duncan’s Test showing that treatment Fdiet 3 differs from Fdiet 4, whereas the treatment Fdiet 3 does differ significantly from Fdiet 1 and Fdiet 2 (P < 0.05), and Fdiet 4 is not significantly different from Fdiet 1 and Fdiet 2 (P > 0.05). The relationship between the dose of the amaranth extracts in the formulated diet and absolute carapace length (mm) of the blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock was quadratic (ACL = -2 x 10-5DAE2+ 0.0166DAE+3.1695; R² = 0.2212; P < 0.05; Figure 2).
Table 2. Average carapace length (mm) and absolute carapace length (mm) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock fed a formulated diet with amaranth extracts at different doses.
Values are means ± standard errors (SE). ACL, absolute carapace length; Fdiet 1, formulated diet without amaranth extract 0 ng/g crab; Fdiet 2, formulated diet enriched with amaranth extract 250 ng/g crab; Fdiet 3, formulated diet enriched with amaranth extract 500 ng/g crab; and Fdiet 4, formulated diet enriched with amaranth extract 750 ng/g crab.
Figure 2. The relationship between the dose of amaranth extracts (DAE) in a formulated diet and the absolute carapace length (mm) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock.
Absolute carapace width
The growth of the absolute carapace width is also calculated from the difference in the size of the parent crab carapace width achieved in a specific time, when the carapace width is measured at the beginning and end of the period. From the measurement results (Table 3), artificial feeding at Fdiet 3, a dose of 500 ng of amaranth extracts/g crab provides relatively high added value to the mean carapace width (13.14 mm) compared to artificial feeding at Fdiet 1, an amaranth extract dose of 0 ng/g crab (6.25 mm); Fdiet 2, 250 ng/g crab (8.98 mm); and Fdiet 3, 750 ng/g crab (1.92 mm), with analysis of variance showing a significant difference (P < 0.05). Similarly, Duncan's test results showed significant differences (P < 0.05), as seen between the treatment Fdiet 3 with Fdiet 1 and Fdiet 4, whereas the treatment Fdiet 2 with Fdiet 3 and the treatment Fdiet 1 with Fdiet 4 did not show significant differences (P > 0.05). The relationship between the amaranth-extract dose in the formulated diet and absolute carapace width was found to be quadratic (ACW = -5 x 10-5 DAE2- 0.0349DAE+5.502; R² = 0.1724; P > 0.05; Figure 3).
Table 3. Average carapace width (mm) and absolute carapace width (mm) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock fed a formulated diet with amaranth extracts at different doses.
Values are means ± standard errors (SE). ACW, absolute carapace width; Fdiet 1, formulated diet without amaranth extract 0 ng/g crab; Fdiet 2, formulated diet enriched with amaranth extract 250 ng/g crab; Fdiet 3, formulated diet enriched with amaranth extract 500 ng/g crab; and Fdiet 4, formulated diet enriched with amaranth extract 750 ng/g crab.
Figure 3. The relationship between the dose of amaranth extracts (DAE) in a formulated diet and the absolute carapace width (mm) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock.
Survival rate
The results show that the different dietary treatments for the female parent crabs during the maintenance period of 40 days in controlled cultivation containers provided a high survival rate (100%) for all treatments (Table 4). The high survival rate value is due to the maintenance in a controlled container cultivation, where no deaths occurred in the female parent crabs. This happens because the water quality (physical and chemical factors) during the study remained in the range conducive for crabs (Table 5).
Table 4. Percentage of average survival rate (%) of blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock fed a formulated diet with amaranth extracts at different doses.
Values are means ± standard errors (SE). H, survival rate; Fdiet 1, formulated diet without amaranth extract 0 ng/g crab; Fdiet 2, formulated diet enriched with amaranth extract 250 ng/g crab; Fdiet 3, formulated diet enriched with amaranth extract 500 ng/g crab; and Fdiet 4, formulated diet enriched with amaranth extract 750 ng/g crab.
Discussion
The growth responses of the crab to the four formulated diets with amaranth extract occurred because of the varied composition of the raw materials used in formulations. Our results demonstrate that the different nutrient levels in the feed, which are especially caused by the levels of amaranth extract. The blue swimming crab needs to maintain the existence of life and its growth, and it will grow well if the available feed contains all the nutrients needed at optimal levels. According to Gutierrez-Yurrita and Montes34, the nutrient composition of essential feed will determine the growth and efficiency of the organisms being fed.
In this experiment (Table 1), the formulated diet that included a dose of amaranth extract influenced the physiological processes of the experimental crab known as absolute weight gain. The highest weight gain was shown by the test crabs receiving the Fdiet 3 treatment (55.03 ± 2.06 g) compared to other feed treatments. The absolute weight gain decreased dramatically with an increase in the amaranth extract dose of 750 ng/g crab (18.05 ± 8.27 g). This dose (Fdiet 3, 500 ng/g crab) performed well, giving good results. In contrast to the findings of the Fdiet 3 treatment, a decrease occurred in the absolute weight of crabs receiving the Fdiet 4 treatment, apparently because of a treatment overdose effect, which causes hormonal imbalances in the body, thereby affecting the absolute weight gain.
Amaranth extract is a molting stimulant containing molting hormone (phytoecdysteroid). Ecdysteroids are the main steroid hormone in arthropods, which functions as a molting hormone and regulate physiological functions, such as growth, metamorphosis and reproduction35. This hormone is secreted by Y-organs in the form of ecdysone. The hemolymph then converts ecdysone into a 20-hydroxyecdysone (20E) active hormone, which is the enzyme 20-hydroxylase found in the epidermis of other organs and tissues. The titers of 20-hydroxyecdysone (20E) in circulation vary throughout the molting phase. Shortly after the ecdysis (molting), the titers are very low, where they remain throughout the intermolt phase.
Our results cast a new light on the administration of amaranth extract at 0-500 ng/g crab, which caused an increase in absolute carapace length (3.60 ± 1.64 - 7.09 ± 0.12 mm) and contributed to relatively large absolute carapace widths (6.25 ± 2.97- 13.14 ± 0.65 mm); at higher doses (750 mg/g crab), a drastic decrease occurred, with successive values of 1.22 ± 1.37 and 1.92 ± 2.15 mm. The increase in absolute carapace length and absolute carapace width was apparently attributable to the synergistic cooperation of the hormones contained in amaranth extract with natural hormones in the body of the crab. This is supported by Fujaya et al.17, who reported that amaranth plants (Amaranthaceae tricolor) contain phytoecdysteroid, which acts as a stimulant for molting and the production of softshell crabs. Kuballa et al.36 noted that molting is physiologically controlled by the molting hormone. Wahyuningsih37 reported an increase in molting percentage by 54% in crabs that received vitomolt supplementation (phytoecdysteroid) at 250 ng/g crabs compared to controls that only showed a 15% increase. Meanwhile, in the study by Susanti38, a molting percentage of 90% was obtained after the vitomolt treatment in formulated diet (933 ng/g feed) compared to only 20%. A dramatic decrease at the higher doses in this study (Fdiet 4) is attributed to the threshold of phytoecdysteroid hormone levels in the blood that affects the molting process in the crab. In addition, a decrease in protein synthesis as a result of the disruption of the physiology of the molting hormone produced was also suspected. Techa and Chung39 suggested the most prominent metabolic action of steroids is activated protein metabolism. Preston and Dinan40 suggest that ecdysteroids also play a role in increasing protein formation by increasing the mRNA synthesis. According to Lafont and Dinan41, ecdysteroid also stimulates carbohydrate metabolism and lipid biosynthesis and acts as an immunostimulant and antioxidant.
It is important to note that the water quality is critical to the survival, health and growth of crabs, especially in semi-intensive and intensive culture. The physical and chemical properties of water should be kept within certain levels. According to Habashy and Hassan42, the required water quality for the maintenance of crustaceans includes salinity, temperature and pH43. Moreover, salinity affects other physiological processes of crustaceans, and various indices exist to evaluate their physiological responses and metabolism, which include glucose, superoxide dismutase and acid phosphatase44,45. Table 5 shows that water salinity between 30.0 to 32.0 ppt was observed in the present study. Salinity is therefore within the range that is highly favorable to the survival of the crab46–48. Mud crabs are highly tolerant to varying salinity conditions ranging between salinity of 10 ppt to 34 ppt49. Water temperature and changes in water temperatures have considerable influence on the rate of growth and survival of aquatic organisms. In this study, temperature during the observation ranged from 26.0 to 27.0°C; therefore, the temperature was in the range of support for the activities of life, growth and reproduction of crab50,51. The pH is a variable that is known to affect survival and development in many brachyuran species. In this study, the range of pH for survival was 7.77–7.96. The optimal pH for growth is from 8–8.552. Low pH can stress crustaceans and cause soft shell and poor survival. At a pH between 7.26 and 8.00, mortality is not usually observed7.
Table 5. The water quality of maintenance media for blue swimming crab P. pelagicus (Linnaeus, 1758) female broodstock fed a formulated diet with amaranth extracts at different doses.
| Water quality parameter | Range |
|---|---|
| Temperature (oC) | 26.0 – 27.0 |
| pH | 7.77 – 7.96 |
| O2 (ppm) | 7.00 – 7.30 |
| CO2 (ppm) | 3.85 – 6.30 |
| Water depth (cm) | 25.0 – 30.0 |
Many studies have been conducted on the oxygen requirements of crustaceans52–54. Liao and Murai53 reported that the oxygen respiration of P. monodon remained constant at dissolved oxygen levels above 3.00 to 4.00 ppm at salinity 5–45 ppt and temperature 20-30°C. In the present study, dissolved oxygen was relatively high, ranging from 7.00–7.30 ppm. In heavily stocked crab ponds, the carbon dioxide can become high as a result of respiration. Boyd and Tucker55 explain that free carbon dioxide is good for the crustacean at no more than 12 ppm and must not be less than 2 ppm. In the present experiments, carbon dioxide levels ranged from 3.85–6.30 ppm (Table 5).
Conclusion
The present study demonstrated that the enrichment of formulated diet with amaranth extracts had a significant effect on the absolute weight gain (AWG), carapace length (ACL), and carapace width (ACW) of Portunus pelagicus (Linnaeus, 1758) broodstock females. The enrichment of amaranth extracts in formulated diets causes an increase in the AWG (18.05-55.03 g), ACL (1.22-7.09 mm) and ACW (1.92-13.14 mm) and yielded a 100% survival rate for all treatments during the 40-day maintenance period. Based on regression analysis, a quadratic relationship was observed between the dose of amaranth extracts found in the formulated diets and the AWG, ACL and ACW.
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Efrizal E, Syam Z, Rusnam R and Suryati S. Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.12688/f1000research.20029.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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Version 1
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PUBLISHED 19 Aug 2019
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How to cite this report:
Saetan J. Reviewer Report For: Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.5256/f1000research.21988.r55042)
The direct URL for this report is:
https://f1000research.com/articles/8-1466/v1#referee-response-55042
https://f1000research.com/articles/8-1466/v1#referee-response-55042
NOTE: it is important to ensure the information in square brackets after the title is included in this citation.
Reviewer Report 21 Oct 2019
Jirawat Saetan,
Department of Anatomy, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
Approved with Reservations
VIEWS 10
Comment to the authors and editor:
Abstract:-
Introduction:
Abstract:-
Introduction:
- Authors should give more information on the vitomolt and also any other plants that contain natural active molting compounds. Examples
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HOW TO CITE THIS REPORT
Saetan J. Reviewer Report For: Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.5256/f1000research.21988.r55042)
The direct URL for this report is:
https://f1000research.com/articles/8-1466/v1#referee-response-55042
https://f1000research.com/articles/8-1466/v1#referee-response-55042
NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article.
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How to cite this report:
Nugroho RA. Reviewer Report For: Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.5256/f1000research.21988.r52710)
The direct URL for this report is:
https://f1000research.com/articles/8-1466/v1#referee-response-52710
https://f1000research.com/articles/8-1466/v1#referee-response-52710
NOTE: it is important to ensure the information in square brackets after the title is included in this citation.
Reviewer Report 24 Sep 2019
Approved with Reservations
VIEWS 13
The manuscripts is quite interesting but need more improvement in some parts, as shown in the annotated manuscript, and with the comments below:
Abstract:
Abstract:
- Methods should be more details, results and
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Nugroho RA. Reviewer Report For: Growth performance and survival rate of Portunus pelagicus (Linnaeus, 1758) broodstock females fed varying doses of amaranth extracts [version 1; peer review: 2 approved with reservations]. F1000Research 2019, 8:1466 (https://doi.org/10.5256/f1000research.21988.r52710)
The direct URL for this report is:
https://f1000research.com/articles/8-1466/v1#referee-response-52710
https://f1000research.com/articles/8-1466/v1#referee-response-52710
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