Southeast Asian Fisheries Development Center
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Effects of weaning on survival and growth of silver therapon (Leiopotherapon plumbeus) larvae fed live and artificial diet
No full textThis study examined the effects of early weaning strategies on growth and survival of the silver therapon Leiopotherapon plumbeus larvae. In Trial 1, four larval age groups (8, 14, 20 and 26 days post‐hatch (dph)) were abruptly weaned to commercial powdered tilapia diet and compared with wild copepod‐fed group as the control. In Trial 2, another batch of three weaning age groups were subjected to gradual weaning (8 dph larvae with 8 days co‐feeding, 14 dph larvae with 6 days co‐feeding and 20 dph larvae with 4 days co‐feeding) with Artemia nauplii prior to weaning on commercial powdered prawn diet and compared with a control group consisted of larvae fed exclusively on Artemia nauplii. Both weaning trials were conducted for 21 days. A gradual weaning strategy promoted better survival (22.2%–40.0%) among weaning age groups than the abrupt weaning strategy (2.2%–36.7%). Except for those weaned at 26 dph, abrupt weaning resulted in significantly poor growth and survival among all weaning age groups compared with the wild copepod‐fed control group. The highest survival and growth were observed in 20 dph larvae with 4 days live food co‐feeding, although the values were significantly lower than the Artemia‐fed control group. These results suggest that abrupt weaning at 26 dph, and gradual weaning for 4 days from 20 dph promote successful rearing of silver therapon larvae and that a microparticulate diet specifically formulated for this species needs to be developed.The study was conducted with funding support from SEAFDEC Aquaculture Department (Study code: Nr-01-F2013B)
Nutritional strategies for efficient reproductive performance of captive Indian white prawn, Penaeus indicus (H. Milne Edwards, 1837)
No full textBroodstock nutrition in penaeid is a vital component of a successful hatchery operation, however, there are still gaps in our present understanding of the nutrient requirements and strategies to optimize successful seed production. The first study determined the influence of different nutrient levels on the maturation of Indian white prawn, Penaeus indicus. Results showed maturation diet with 55/12 protein/lipid combination resulted in best reproductive performance of P. indicus in terms of maturation and offspring quality similar to that achieved in broodstock fed with fresh diet. Experimental maturation diet with the lowest nutritional inclusion resulted in poor maturation rates of broodstock, while treatments with high lipid supplementation resulted in higher lipid accumulation in the hepatopancreas and low survival. The second and third components of the dissertation determined the effect of polychaete extract supplementation on male and female broodstock maturation, respectively. Results showed inclusion (0.25% and 0.50%) of polar lipid fraction (PLF) in the diet resulted in best ovarian maturation with significantly increased ovarian vitellogenin (Vg) expression of female P. indicus. Neutral lipid fraction (NLF) and total soluble fraction (TSF) at 0.50% and 1.00% inclusion levels equally promoted ovarian maturation of female P. indicus broodstock but with lower ovarian Vg expression. All dietary treatments except for 0.25% NLF and TSF improved P. indicus ovarian maturation compared to those fed basal or fresh feed diets. Meanwhile, the lowest inclusion of TSF and NLF resulted in higher sperm counts while PLF did not improve sperm production. Polychaete extract supplementation in the maturation diet of male P. indicus broodstock did not significantly increase sperm count compared to those fed with the basal diet. Male and female broodstock have different reproductive responses to polychaete supplementation, suggesting differences in their requirements, hence, nutritional manipulation should be made sex-specific. Rearing broodstock, either monosex or mixed sex did not influence gonad maturation, sperm quantity and quality, and mating behavior and success. Overall these findings indicate that a sex-specific nutritional intervention is a practical approach to attain efficient gonad maturation and reproductive success in the breeding of P. indicus.Southeast Asian Fisheries Development Center/Aquaculture Department (SEAFDEC/AQD) funding support (FD-02-C0219T)
Acute toxicity of garlic (Allium sativum) extract to snubnose pompano (Trachinotus blochii) juvenile
Get PDFGarlic (Allium sativum) is a well-known medicinal herb which has been shown to possess anti-microbial and anti-parasitic properties. This study was conducted to test the toxicity levels of snubnose pompano (Trachinotus blochii) juvenile to garlic (Allium sativum) extract by determining the cumulative mortality and median lethal concentration (LC50). Test fish were exposed to six concentrations of the extract (2.5, 5.0, 7.5, 10, 20 and 30 ppm) in a 96-hour static bioassay. Cumulative mortality was highest at 100 % for 30 ppm garlic extract, with mortalities found to increase with increasing concentration. Test fish exposed to 20 and 30 ppm exhibited weak and static behavior. The LC50 of garlic extract to T. blochii was found to be 7.48 ppm at 96 h. Findings of the present study suggest that aqueous garlic extract up to 5 ppm can be safely used in pompano for prophylactic purposes.The author expresses her gratitude to the Government of Japan Trust Fund (GoJTF6 (8400-T-RD-FH0215) for funding this work. Thanks are due to Ms. Haydee Dumaran-Paciente and Mr. Elvis Biñas for their technical assistance
Department of Animal Health (DAH) report of emergency diseases - prevention and control of shrimp diseases in from 2016 to 2018
No full textAcute Hepatopancreatic Necrosis Disease (AHPND), known as Early Mortality Syndrome (EMS) before 2013, was first reported in Vietnam from the Mekong River Delta without laboratory confirmation in the end of 2010. Vibrio parahaemolyticus was recognized as the causative agent of AHPND reported by Dr. Tran Loc in 2013. From 2010 to 2015, AHPND spread quickly to a wide range of shrimp production areas in Viet Nam. White Spot Disease (WSD), in dual infection with AHPND, cause serious disease, each year nearly 1 % in total culture area stopped operation. Although the diseases decreased significantly from 2013 to 2018, AHPND and WSD are still the most serious problem encountered by shrimp farmers in main shrimp production areas. Both tiger shrimp (Penaeus monodon) and whiteleg shrimp (Litopenaeus vannamei) have been infected with AHPND and WSD; most cases occur 15–60 days after stocking. AHPND and WSD occur year round; however, it is most frequently observed between March to September. Vietnam has alleviated the effect of AHPND and WSD effectively in the current year. This can be attributed to the application of multiple solutions to prevent and control AHPND and WSD such as (1) improve farmers’ production conditions, awareness, facilities and bio-security measures; (2) implement active surveillance in main shrimp production areas for early warning; (3) broodstock and postlarvae are not accepted if positive for any OIE listed diseases; (4) movement control to prevent spreading disease; (5) encourage developing disease-free farms; (6) improve capacities and complete aquatic animal health system
Single and mixed species of microalgae as larval food for the tropical sea cucumber Holothuria scabra
No full textDifferent microalgae as larval food for Holothuria scabra, a high-value sea cucumber species with hatchery technology continually being refined to improve production, were studied. Two experiments were conducted to determine the performance of the larvae—first, the use of single-algal diet of either Chaetoceros calcitrans, Rhodomonas sp., or Tetraselmis tetrathele as feed; and second, the use of a combination of two algal species, C. calcitrans + Rhodomonas sp., C. calcitrans + T. tetrathele, or Rhodomonas sp. + T. tetrathele as feed. For both experiments, hatched larvae at 2 days post-fertilization (DPF) were used for initial stocking at a density of 200 larvae L−1. Growth, development, and survival were monitored until more than 50% of the larval population were considered as competent larvae (late auricularia). In the first experiment, during the early stage of development (early aricularia), larvae fed Rhodomonas sp. were larger compared to other treatments. However, when the larvae reached middle and late auricularia, they performed better when fed with C. calcitrans. Those larvae fed with C. calcitrans were significantly larger and showed faster development to competent larvae. In the second experiment, larvae fed mixed C. calcitrans + Rhodomonas sp. showed better performance in growth, development, and survival. The present study showed that C. calcitrans, when used solely as feed or in combination with Rhodomonas sp., promoted better growth, development, and survival of H. scabra larvae
Comparative transcriptome profiling of heat stress response of the mangrove crab Scylla serrata across sites of varying climate profiles
No full textBackground: The fishery and aquaculture of the widely distributed mangrove crab Scylla serrata is a steadily growing, high-value, global industry. Climate change poses a risk to this industry as temperature elevations are expected to threaten the mangrove crab habitat and the supply of mangrove crab juveniles from the wild. It is therefore important to understand the genomic and molecular basis of how mangrove crab populations from sites with different climate profiles respond to heat stress. Towards this, we performed RNA-seq on the gill tissue of S. serrata individuals sampled from 3 sites (Cagayan, Bicol, and Bataan) in the Philippines, under normal and heat-stressed conditions. To compare the transcriptome expression profiles, we designed a 2-factor generalized linear model containing interaction terms, which allowed us to simultaneously analyze within-site response to heat-stress and across-site differences in the response.
Results: We present the first ever transcriptome assembly of S. serrata obtained from a data set containing 66 Gbases of cleaned RNA-seq reads. With lowly-expressed and short contigs excluded, the assembly contains roughly 17,000 genes with an N50 length of 2,366 bp. Our assembly contains many almost full-length transcripts – 5229 shrimp and 3049 fruit fly proteins have alignments that cover >80% of their sequence lengths to a contig. Differential expression analysis found population-specific differences in heat-stress response. Within-site analysis of heat-stress response showed 177, 755, and 221 differentially expressed (DE) genes in the Cagayan, Bataan, and Bicol group, respectively. Across-site analysis showed that between Cagayan and Bataan, there were 389 genes associated with 48 signaling and stress-response pathways, for which there was an effect of site in the response to heat; and between Cagayan and Bicol, there were 101 such genes affecting 8 pathways.
Conclusion: In light of previous work on climate profiling and on population genetics of marine species in the Philippines, our findings suggest that the variation in thermal response among populations might be derived from acclimatory plasticity due to pre-exposure to extreme temperature variations or from population structure shaped by connectivity which leads to adaptive genetic differences among populations.This work was funded by the Department of Science and Technology Philippine Council for Agriculture and Aquatic Resources Research and Development (DOST-PCARRD) Mangrove Crab Program to De La Salle University-Manila through MCAL. AMSS was partially funded by University Research Coordination Office, De La Salle University-Manila. The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript
Interaction effect of light intensity and photoperiod on egg hatchability, survival and growth of polychaete Marphysa iloiloensis from larva to juvenile
No full textPolychaetes are of high commercial interest as potential feed in aquaculture industry. Despite this, knowledge of polychaete culture is limited. The goal of this study is to develop a protocol that maximizes survival and growth of polychaetes from embryonic to juvenile stages. To determine the effect of light intensity and photoperiod on Marphysa iloiloensis, two experiments were conducted; 1 - hatchability (embryo-larva; 24 h duration) and 2 - survival and growth (larva-juvenile; 29 d duration). Both experiments followed a 3 × 3 factorial design using three light intensities (3.4, 64.4, and 157 μmol m−2 s−1) and three photoperiods (1 L: 23D, 3 L: 21D, and 6 L: 18D) with four replicates each. The best light regime was compared to the control (0 μmol m−2 s−1). Hatching success was significantly lower in treatments exposed to 157 μmol m−2 s−1 regardless of photoperiod (P < 0.05). Survival at juvenile stage was significantly dependent on the interaction between light intensity and photoperiod (P < 0.01). Survival was higher in both 0 μmol m−2 s−1 and 3.4 μmol m−2 s−1 (all photoperiods). Survival decreased significantly in 64.4 μmol m−2 s−1 and 157 μmol m−2 s−1 under both 3 L: 21D and 6 L: 18D photoperiods. Prolonged exposure to higher light intensity compromised the survival of the polychaete from larval to juvenile stage while growth was not affected. These findings suggest that either continuous darkness or a light intensity of 3.4 μmol m−2 s−1 is the best culture condition from embryonic to juvenile stage of mud polychaete M. iloiloensis to optimize production.This study was funded by the Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD) under the study code Br-02-Y2016T
Optimum stocking density and feeding level for laboratory‐reared early‐stage silver therapon (Leiopotherapon plumbeus) larvae
No full textGrowth, survival and feeding of early‐stage silver therapon Leiopotherapon plumbeus larvae reared at different stocking densities and feeding levels were examined. Larvae (8 days post hatch (dph); 0.38–0.50 mg body weight (BW); 5.33–6.90 mm in total length (TL)) were stocked at densities of 5, 15, 25 and 35 larvae/L and co‐fed with live food (Brachionus rotundiformis and Artemia nauplii) and formulated microdiet or fed Artemia alone for 28 days. Another batch of 8 dph silver therapon larvae (0.65 mg BW; 9.47 mm TL) were stocked at 15 larvae/L and were fed 1, 2 or 5 Artemia nauplii/mL for 28 days. Survival at lower densities (5 and 15 larvae/L) was significantly improved than in high‐density reared larvae. Furthermore, larvae fed Artemia alone showed higher survival (20.4%–81.4%) than those offered live food and formulated microdiet combined (3.5%–32.9%) in each stocking density, indicating the suitability of Artemia for early‐stage silver therapon larvae. Growth parameters were significantly affected by stocking density in larvae fed Artemia alone but not in the live food and formulated microdiet co‐fed group. No significant differences in growth and survival were observed in silver therapon larvae reared on three feeding levels. However, higher feed intake at 5 nauplii/mL resulted in significantly higher body lipid contents than those fed 1 or 2 nauplii/mL. The results suggest that larvae held at stocking densities of 5 and 15 larvae/L and fed 5 Artemia nauplii/mL promote maximum growth, survival and higher feed intake of early‐stage silver therapon larvae under laboratory conditions.This study was supported by SEAFDEC Aquaculture Department under the Study Code: Nr-01-F2013B
Growth and survival of oyster Crassostrea iredalei (Faustino, 1932): A comparison of wild and hatchery-bred spat in grow-out culture
No full textOyster farming is an important industry both in developed and developing countries. The high demand for oysters has caused overexploitation of natural stocks. This led to dwindling spat fall and unstable production. This study was conducted to compare growth and survival of wild and hatchery-bred spat of the oyster Crassostrea iredalei in grow-out culture. Results of the experiment revealed that both wild (n = 1450) and hatchery-bred spat (n = 1450) had comparable growth rates in grow-out culture. Growth rates of wild and hatchery-bred oysters did not differ significantly at 5.69 ± 0.88 mm shell length (SL) and 8.85 ± 1.07 g body weight (BW) mo−1 and 6.88 ± 1.33 mm SL and 8.26 ± 1.15 g BW mo−1, respectively. Growth rates, in terms of shell length, both for wild (p < 0.05, r = 0.74) and hatchery-bred oysters (p < 0.05, r = 0.76), showed strong positive correlation with salinity. Meat yield was almost the same at 16.41 ± 0.57% for wild oysters and 15.59 ± 0.37% for the hatchery-bred ones. Proximate composition of dried whole flesh oyster samples also showed the same amounts of crude protein, crude fat, crude fiber, nitrogen free extract, and ash in both wild and hatchery-bred oysters. The length-weight relationships of wild [W = 0.000492 L2.6512 (R2 = 86.8%, p < 0.001)] and hatchery-bred [W = 0.000052 L3.1779 (R2 = 92.6%, p < 0.001)] C. iredalei were also calculated from the length and weight data obtained during the duration of culture and revealed higher b for the smaller hatchery-bred oysters. Moreover, mean survival at harvest did not significantly differ at 85.03 ± 1.09% for wild oysters and 85.31 ± 1.40% for the hatchery-bred ones (Two-sample t-test, p > 0.05). The results of this study showed the potential of hatchery-bred oyster spat as seeds for grow-out culture to address the declining number of spat fall in natural oyster beds. Producing the same quality of oysters, it can be inferred that the hatchery-bred spat are just as competent as their wild conspecifics.The Project Team greatly appreciates the Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD) for funding this three-year project (Project Code 6286-TRD-DOST-O4); Dr. Mari-Ann M. Acedera, Ms. Ester C. Zaragoza, Ms. Adela C. Corpuz and all the staff of the Marine Resources Research Division of DOST-PCAARRD for their assistance and support from proposal submission to project termination; the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) for personnel support (Budget Code 5106-T-RD) and for facilitating the smooth implementation of the project; Mr. Patrick Frances Alicante, Mr. Silverio Tibudan and Mr. Winnie Tibudan for their kind assistance in the field; the Oyster Hatchery Team for providing the hatchery-bred spat; the Local Government Unit and the people of New Washington, Aklan for welcoming the team and allowing the conduct of the experiment in their locality; and the four anonymous journal reviewers for painstakingly reviewing the manuscript