Sea Bass Fry Research Articles

Effect of dietary L-tryptophan on cannibalism, growth and survival of Asian seabass, Lates calcarifer (Bloch, 1790) fry

The effect of L-tryptophan (TRP) supplemented diets at levels of 0, 0.5, 1.0, 1.5 and 2% on cannibalism, survival and growth performance of Asian seabass, Lates calcarifer (Bloch, 1790) fry was evaluated. Thirty days old seabass fry (mean weight: 0.31±0.16 g) were reared for 45 days in a recirculating aquaculture system. Results of the present experiment showed that L - tryptophan (TRP) supplementation from 0.5 to 2% in diet significantly (p<0.05) reduced cannibalism compared to control diet and did not affect growth performance. The lowest survival percentage (14%) was noticed in control group, whereas a higher survival percentage (33.33 to 39.80) was observed in TRP supplemented groups. Coefficient of size variation (%) ranged from 21.50 to 91.61 and decreased with increased level of TRP supplementation, Similar results were also obtained in size heterogeneity. Based on the results of the study, it is recommended to supplement 0.5% of TRP in larval diet to reduce cannibalism and improve survival of seabass fry.

Effects of different carotenoid supplementation sources with or without sodium taurocholate on growth, feed utilization, carotenoid content and antioxidant status in fry of the European seabass,Dicentrarchus labrax

A total of 210 European seabass fry with an average body weight of 0.51 ± 0.03 g were divided into seven experimental treatments (three replicates per treatment). The seven experimental diets (45.64% CP) were formulated to contain synthetic astaxanthin (SA; 0.1 g kg−1), marigold flower meal (MFM; 0.2 g kg−1) or crab waste meal (CM; 10 g kg−1), with or without sodium taurocholate (ST; 0.4 g kg−1); the control diet contained no supplementation. The experiment was conducted for 8 weeks. The results show that seabass fry fed the diets containing different sources of carotenoids, especially with ST, demonstrated higher growth efficiency, survival (%), feed efficiency, protein and ether extract contents of fish body. The best results were found with DietMFM+ST. Whole-body carotenoid levels increased significantly with all supplementation treatments; the highest level was observed with SA, followed by fish fed DietMFM and DietCM, especially with ST co-supplementation. Moreover, thiobarbituric acid-reactive substances were significantly reduced in fish fed the diets containing different sources of carotenoids compared to the control diet. The total antioxidant status significantly increased in fish fed DietSA and DietCM alone or with ST compared to the control group. In conclusion, these results reveal that DietMFM+ST is the most suitable treatment for improving growth, feed efficiency, and the protein and ether extract contents of seabass fry compared to other sources of carotenoids. The best oxidant/antioxidant balance and carotenoid content were achieved using SA, CM and MFM with ST supplementation.

Length-weight relationship, condition factor and cannibalism in Asian seabass Lates calcarifer (Bloch, 1790) reared in nursery

The length-weight relationship of Asian seabass Lates calcarifer (Bloch, 1790) reared in net cage hapa was studied for a period of 45 days. A total of 22,500 nos. of seabass fry (mean length 1.76 ± 0.39 cm; mean weight 0.132 ± 0.10 g) were stocked in fifteen hapas @ 1500 nos. per hapa (2x1x1m) and fed twice daily with farm made feed @ 10% of the body weight initially and reduced to 8% later on. Sampling was done at an interval of 15 days to assess the growth, survival, cannibalism and performance. On termination of the experiment, survival was 25%. Cannibalism contributed 11–51% to the total mortality. K value >1 indicated healthy condition of fish. During the entire culture period, growth was negatively allometric (b<3). Growth showed an increasing trend from 150.5±13.4 to 732.6±7.7. The study concludes that the hapa system is one of the best option for carrying out the nursery rearing of seabass.

The Applicability of Activated Carbon, Natural Zeolites, and Probiotics (EM®) and Its Effects on Ammonia Removal Efficiency and Fry Performance of European Seabass Dicentrarchus labrax

Ammonia is toxic to fish if allowed to accumulate and not-properly managed in fish production systems. Six treatments were studied to evaluate the effectiveness of applying three commercial Ammonia Removal Products (Activated Carbon, Natural Zeolite and Effective Micro-organisms (EM®)). These treatments are: (1) C, Control, (2) AC5, activated carbon at 5ppt, (3) AC10, activated carbon at 10 ppt, (4) Z5, Zeolite at 5 ppt, (5) Z10, zeolite at 10 ppt, and (6) EM400, EM at 400 ppm. European Seabass fry (240.74 mg/fish IW) were stocked into glass aquaria (50 litres each) at density of 20 fry/aquarium. Water exchange rate was 20% daily and the experiment continued for 35 days. Fish were fed on experimental diet contained 51.37% crude protein, three meals daily, and six days weekly. Data of water quality, survival and growth performance were recorded weekly. The results revealed that, ammonia removal efficiency of the tested products was significantly (P ≤ 0.05) better than control, with no significant differences (P>0.05) between the evaluated products. The best ammonia removal rate (76.60%) was obtained at Z10 treatment. Fish survival (%) ranged between 37.78% to 90% with highly significant (P ≤ 0.05) differences between treatments. The best survival (%) was obtained at EM400 (90%), while the lowest (37.78%) was obtained at AC5 and AC10 treatments. Growth performance was significantly (P ≤ 0.05) higher at (EM400, Z10, and Z5), compared with treatments (AC10, AC5, and C). It could be clearly concluded that, using Probiotics (EM®) and Zeolite for ammonia removal might be a good potential alternative choice, while activated carbon cannot be recommended for marine fish rearing tanks in terms of low survival and growth performance and also the higher expected production cost.

Effects of Stocking Density and Green Water on Some Performance of European Sea Bass Fry (Dicentrarchus labrax L.) During Post – weaning Period

Effects of Stocking Density and Green Water on Some Performance of European Sea Bass Fry (Dicentrarchus labrax L.) During Post – weaning Period

Evaluation of garlic and onion powder as phyto-additives in the diet of sea bass (Dicentrarcus labrax)

The present study is a preliminary work which was conducted to evaluate the impact of adding 3 levels of garlic (10, 20 and 30g/kg diet) as well as onion powder (5, 10 and 20g/kg diet) in a basal diet of sea bass (Dicentrarcus labrax) fry (initial weight=0.4±0.05g/fish) on growth performance, feed utilization, body composition, survival rate and some hematological parameters. The present results suggested that dietary garlic or onion powder administrated separately at levels of 30 or 10g/kg respectively could improve survival, growth and feed utilization of sea bass fry. Administration of garlic and onion indicates a slide edge for garlic to onion in growth, feed utilization and fish protein content. It will also induce a significant increase in some blood variables (hemoglobin content, hematocrit value, mean corpuscular volume, mean corpuscular hemoglobin and leukocytes count) in treated fish when compared to the control fish group.

Nursery Culture of Grouper (Epinephelus fuscoguttatus Forsskal) and Sea Bass (Lates calcarifer Bloch) in Brackish Water Ponds: Co-Feeding of Zooplankton and Formulated Diets Containing L-Tryptophan

This study compared co-feeding zooplankton (ZP, mixed copepods and mysids) and formulated diets (FD) supplemented with L-tryptophan (TRP) on the survival and growth of grouper and sea bass fry nursed in brackish water ponds. Grouper (84 fry m−3) and sea bass (150 fry m−3) were reared for 30 days and 60 days, respectively, in net cages within two separate 743 m2 nursery ponds. Five treatments (with three replicates each) were compared (P < 0.05): FD-1 = ZP + basal FD (no added TRP, but containing 0.29% endogenous TRP); FD-2 = ZP + (FD 0.58% TRP); FD-3 = ZP + (FD 1.22% TRP); FD-4 = ZP + (FD 2.50% TRP); and FD-5 = minced fish (Sardinella sp.) + basal FD (no additional TRP). TRP supplementation in grouper diets produced no significant affect on growth but increased survival at rates of 0.58% and above. TRP supplementation at 2.5% (FD-4) produced significantly better sea bass growth than other diets but had no affect on survival. Zooplankton improved both survival and growth in both grouper and sea bass juveniles compared to the minced fish diet, and may be a practical and lower cost alternative to indoor nursing.

Optimization of feeding frequency of Asian seabass ( Lates calcarifer) fry reared in net cages under brackishwater environment

An experiment was conducted in brackishwater environment to determine the optimal feeding frequency for growth, effective feed conversion, survival, shooters emergence and size variation in Asian seabass fry reared in the net cages. Four feeding frequencies of one (T1), two (T2), three (T3) and four (T4) times a day were evaluated as treatments in triplicate for a period of 5 weeks. Hatchery produced weaned seabass fry (25.9 ± 0.3 mm/203.8 ± 4.6 mg size) stocked at 120 numbers per cage were fed with a commercial marine fish larval diet containing 55% crude protein at 10% of the biomass daily for the first 3 weeks, followed by 8% for the remaining 2 weeks. Although, the highest growth was recorded in T3, the final length (45.9 ± 0.3 mm) and weight (1203.8 ± 4.6 mg) did not differ significantly ( P > 0.05) from that of T4. Whereas, fish with one or two times feeding exhibited significantly lower growth ( P < 0.05). Daily weight gain, percentage weight gain and specific growth rate were significantly higher in T3 ( P < 0.05), while there was no significant variation ( P > 0.05) between T3 and T4. Significantly higher survival of 75.89 ± 4.17% was recorded in T3 than those of one and two times fed fish ( P < 0.05). The fish in T3 had significantly improved feed conversion ratio ( P < 0.05). No significant differences were recorded among treatments for the cumulative number of shooters separated and coefficient of variation in the harvest weight, which were ranging from 9.67 to 12.00 and 0.113 to 0.124, respectively. This study infers that the Asian seabass fry can achieve maximum growth, survival and better feed conversion when they are fed a given ration with three times feeding daily in brackishwater net cage rearing. The findings also have practical significance towards establishing Asian seabass seed rearing package and will directly benefit the nursery operators.

Effects of Live Food Organisms and Formulated Diets on Growth, Survival, and Body Protein of Asian Sea Bass Fry (Lates calcarifer, Bloch)

The effects of the live feeds, Artemia, Moina, and Tubifex, and a formulated diet on the survival, growth, and body composition of fry (0.05±0.001 g) of the Asian sea bass, Lates calcarifer (also called barramundi), were evaluat- ed. The formulated diet was supplemented with dry Bombay duck fishmeal (10%) as an attractant. The experiment was conducted for 30 days in 40-l glass aquaria containing 30 l fresh water. The fry fed Artemia had the best survival (70%) and growth rate (6.48±0.10%). Fry fed Moina and formu- lated diet had 60% survival, not significantly different from fry fed Artemia. Survival was poor (30%) in fry fed Tubifex. Body protein and lipid contents differed significantly among treatments. The present study suggests that Artemia nauplii is the better feed for Asian sea bass fry but formulated diet can be used as a substitute since growth and survival were similar.

Evaluation of Fish Meals as Natural Feed Stimulants on the Feeding Behaviour of Fry and Juveniles of Lates calcarifer (Bloch)

Six purified diets were prepared for this experiment. Five of these six diets contained fish meals of five different fishes namely Bombay duck, Anchovy, Lesser sardine, Ribbon fish and shrimp head as natural stimulants for sea bass fry and juveniles. These five diets were prepared by adding 10% of each stimulant by weight in the purified diet. The sixth diet (F) was without stimulant and considered as control. The experiment was conducted on sea bass fry, 20 (+0.02) mm total length and juvenile, 217 (+0.15) mm total length by using one fish and two fish per tank respectively. The results indicated that Bombay duck meal containing diet i.e. diet ‘A’ has significant stimulating effect on the feeding behaviour of fry and also in juveniles of sea bass although the positive responses were higher in the case of juveniles (30 in case of fry and 34 in case of juveniles). Further, there were 34 positive responses in the case of two juvenile sea bass per tank experiment where as it was 30 in the case of two fry per tank experiment. The feeding responses were significantly different with two fish per tank as compared to one fish per tank showing that the number of fish had an influence on the feeding behaviour of both fry and juveniles. However, no feeding response was observed in the control diet. The study also revealed that Bombay duck meal is better and superior as feeding stimulant over the other fish meals for the Sea bass fry and juveniles.

APLIKASI MINYAK CENGKEH SEBAGAI OBAT BIUS PADA KAKAP PUTIH (Lates calcarifer Bloch)

The objective of this study was to determine the safety and efficacy of clove oil as an anesthetic in sea bass (Lates calcarifer) and the potential application of clove oil as anesthetic to facilitate the sea bass fry transportation. Acute toxicity test indicated the 24-hr LC50 value of clove oil in sea bass fry as 30 ppm with slope function of 1.079 (1.05 to 1.107). In efficacy test, fish were exposed to 5, 10, 15, 20 and 25 ppm of clove oil for 15 minutes. At 5 ppm, clove oil caused only sedation effect (partial loss of reaction to external stimuli) while at 20 ppm, fish entered anesthesia stage (failure to respond to external stimuli) within about 3 minutes. Fish recovered from a 15-min period of exposure in 20 ppm clove oil within less than 10 minutes following removal from the anesthetic solution. There was neither mortality nor abnormal behavior of fish during 15-min exposure of clove oil as well as during 7 days post recovery from anesthesia. The potential application of clove oil as an aid in the transport of sea bass fry in plastic bag was also investigated. At 5 ppm, clove oil could reduce activities of the fish without loss of equilibrium (sedation stage) during the 4 hour simulated transport at 50 fish per 1,000 ml sea water (15 ppt). At 20 ppm, clove oil caused loss of equilibrium in fish resulting in the anesthesia stage throughout the 4 hour period. However, there was no improvement on survival rate and fish behavior with the use of clove oil during and after this 4 hour transport. Simulated transport at 50 fish per 500 ml sea water (15 ppt) for 8 hour did show better significant survival rate with additional of 5 and 20 ppm clove oil. In both short and long term transport study, clove oil did show the benefit by reducing the fish activities judging from the reduction of oxygen consumption, ammonia and carbon dioxide levels. Addition of appropriate concentration of clove oil in transport water ensured that the fish would stay calm by reducing fish activity and therefore, prevented any drastic changes of water qualities.

Temperature-dependency of Betanodavirus infection in SSN-1 cell line

This study examined the in vitro effects of temperature on Betanodavirus infection in the SSN-1 cell line. A Betanodavirus isolated from moribund sea bass fry Dicentrarchus labrax farmed in the Adriatic Sea and characterised as a RGNNV (Redspotted Grouper Nervous Necrosis Virus) genotype was used. Virus-infected SSN-1 cells were incubated at temperatures between 10 and 30 degrees C and observed for cytopathic effects daily for 15 d. Cell-free and cell-associated viral growth were evaluated by 50% tissue culture infectious dose (TCID50) titration at 0, 24, 48, 72, 96, 144, 192, 240, 312 and 360 h post-infection. Virus replication was observed at all temperatures from 15 to 30 degrees C. The optimal temperature for virus growth was 25 degrees C. A temperature of 10 degrees C was detrimental to the growth of the SSN-1 cells and cell death interfered with interpretations of viral growth. The isolate of Betanodavirus from Italian sea bass in this study demonstrates a different temperature range for growth compared to previous reports for related Betanodavirus strains, most likely due to an adaptation to the normal environmental temperatures of the host fish species of origin.

Effect Of Stimulants On Feeding Response, Feeding Behavior, And Growth Of Fry Of Sea Bass, Lates Calcarifer (Bloch, 1790)

The influence of four stimulants (glycine, proline, L-lysine, and Bombay duck fishmeal) on the feeding behavior of sea bass fry was studied. The substances were added at a level of 1% of the weight of moist pellets made from purified diets. Feeding responses were observed in glass tanks containing one or two fish.The fishmeal had significantly greater stimulating effect on the feeding behavior than the chemical substances. Feeding responses were significantly different when there were two fish in the tank. Inclusion of fishmeal at a 10% level (compared to 1%, 5%, 7.5%) produced the greatest ingestion response (50%). Compared to 7.5%, inclusion at 10% produced a significantly higher weight gain (0.54±0.03 g), FCR (1.79), and PER (1.20). The pre- sent investigation revealed that Bombay duck meal is a better natural fish feed stimulant than the tested chemicals.

A novel ‘skinny pot‐belly’ disease in Asian seabass fry, Lates calcarifer (Bloch)

In Singapore, viral nervous necrosis (VNN) is considered to be the most serious disease of farmed Asian seabass fry, Lates calcarifer (Bloch) (barramundi), causing mortalities of 80–100% and heavy economic loss (Lim, Chong & Kueh 1997; Kasornchandra 2002). When some ‘skinny pot-bellied’ seabass fry were presented to the Aquatic Animal Health Laboratory early in 2004, with a history that the disease was usually first observed at around 3 weeks of age, VNN was the prime suspect. Instead of central nervous lesions, however (Munday, Langdon, Hyatt & Humphrey 1992), histopathological examination showed the presence of a severe necrotizing and ulcerative enteritis, progressing to perforation and peritonitis, with disseminated multifocal granulomas. Associated with these lesions were numerous bacterial colonies. This preliminary report presents a description of this novel systemic bacterial disease of young seabass, typified by emaciation and abdominal distension, and associated with high mortality. Immunohistochemistry suggests an association with Edwardsiella ictaluri.

Vaccine development in sea bass fry (Dicentrarchus labrax L., 1758) against vibriosis.

Vaccine development in sea bass fry (Dicentrarchus labrax L., 1758) against vibriosis.

Effect of dietary taurine supplementation on growth performance and feed selection of sea bass Dicentrarchus labrax fry fed with demand-feeders

: Two series of experiments were conducted for the evaluation of the effect of dietary taurine supplementation on survival, growth performance and feed preference of sea bass Dicentrarchus labrax fry when fed with demand-feeders a fish/soybean meal-based diet. In the first experiment, fish were imposed one of four diets supplemented with taurine (0, 0.1, 0.2 or 0.3% taurine on a dry weight basis), while in the second they had simultaneous free access to the four diets supplemented with taurine. When not allowed to choose, fish exhibited better specific growth rate of 3.2 and 3.2% per day with diets supplemented with 0.2 and 0.3% taurine than those of 2.3 and 2.2% per day of 0 and 0.1% taurine, respectively. When fish were free to access the diets, they selected more actively the 0.2 and 0.3% taurine-supplemented diets than the 0 and 0.1% taurine. As survival was not significantly different among trials, the results indicate that sea bass fry require a 0.2% taurine in the diet for better growth when fish meal and soybean meal are the primary sources of protein. The positive correlation between growth performance and nutrient preference is discussed as a method for improvement of fry food formulation.

Use of Juvenile Instar Diaphanosoma Celebensis (Stingelin) In Hatchery Rearing Of Asian Sea Bass Lates Calcarifer (Bloch)

The effects of size, dry mass intake and nutritional value of the brackishwater cladoceran, Diaphanosoma celebensis, on the growth and survival of 15-30 day sea bass (Lates calcarifer) lar- vae reared in a static green water system were determined. The highest specific growth rate (29.4%/day) was attained in larvae fed a 1:1 combination of Artemia nauplii and adult Diaphanosoma but it was not significantly different (p&gt;0.05) from fish fed only adult Diaphanosoma (28.8%/day) or only juvenile instar Diaphanosoma (28.6%/day). Survival rates of larvae (92.4- 99.0%) fed the different live diets did not significantly differ (p&gt;0.05). Larvae markedly prefered juve- nile instar Diaphanosoma over Artemia nauplii and adult Diaphanosoma. The crude protein con- tents of juvenile Diaphanosoma (58.7%), adult Diaphanosoma (58.3%) and Artemia (56.7%) were substantially high and satisfied the dietary protein requirements of larvae. The fatty acid profile of the sea bass fry reflected the lipid composition of the live diet. Improved growth, survival and dry mass intake in larvae indicate the potential of juvenile Diaphanosoma in the hatchery rearing of sea bass larvae.

The gill is a major organ for antibody secreting cell production following direct immersion of sea bass (Dicentrarchus labrax, L.) in a Photobacterium damselae ssp. piscicida bacterin: an ontogenetic study

Extremely high numbers of antibody secreting cells (ASC) were observed in the gills of sea bass fry immunised at three different age/sizes (initial weight of 0·1, 2 and 5g) by direct immersion in a Photobacterium damselae spp. piscicida bacterin. The relatively low ASC production in the head kidney and spleen suggests that the systemic compartment was only slightly stimulated upon immersion vaccination. There was no response of corresponding magnitude in the gut as the one observed in the gills. A clear age effect was observed in the ASC response of the different groups, especially visible in the gills. Significantly higher numbers of specific ASC were observed in the gills of the two oldest groups (initial weight of 2 and 5g) compared with the youngest fish (initial weight of 0·1g), but the oldest groups were not significantly different from each other. Additionally, a more rapid response was observed with the ageing of the fish, with peak responses in all the organs at day 18, 16 and 8 post-immunisation in the smallest to largest fish, respectively. There was no evidence that direct immersion exposure to P. damselae ssp. piscicida at the earliest stages used in the present study (0·1g) was tolerogenic. In the context of present knowledge, this study strongly supports the importance of the route of immunisation to locally stimulate ASC and the importance that the gills might have in specific responses.

Development of a tropical marine fish cell line from Asian seabass ( Lates calcarifer) for virus isolation

A tropical marine fish cell line (SF) was established from Asian seabass ( Lates calcarifer) fry. The cell line was maintained in Earle's minimum essential medium (EMEM) supplemented with foetal calf serum and incubated at 25°C. The susceptibility of the cell-line at the 16th, 35th and 46th subculture to several iridoviruses, birnaviruses, reoviruses, a rhabdovirus, and a nodavirus was studied. Cytopathic effect (CPE) was observed daily after virus inoculation and viral replication efficiency was determined for six viruses. SF cell cultures infected with an iridovirus, a nodavirus and a reovirus were further elucidated by electron microscopy. All the viruses tested were shown to induce CPE on SF cells. This suggests that the SF cell line has good potential for the isolation of various fish viruses. The SF cell line consists predominantly of epithelial-like cells and has been subcultured 85 times over a period of 24 months.

Drug assimilation in the tissue of European sea bass (Dicentrarchus labrax) fry delivered orally through bioencapsulation

Assimilation levels of the antibacterials trimethoprim (TMP) and sulfamethoxazole (SMX) in sea bass (Dicentrarchus labrax) fry tissue administered orally were investigated. A 1:5 TMP and SMX combination incorporated in an oil emulsion (Selco) at 20 % and 40 % concentrations (w/w) were bioencapsulated in Artemia (Instar II) nauplii. Chemotherapeutics-loaded ('medicated') nauplii were fed to the sea bass fry and drug concentrations in the tissue were analysed by high-performance liquid chromatrography (HPLC). Fish fed 40 % 'medicated' Artemia assimilated significantly higher levels of chemotherapeutics compared with those fed 20 % 'medicated' Artemia. Chemotherapeutics given at 40 % reached peak levels (19.3 mu g TMP/g DW and 23.31 mu g SMX/g DW) within 2 h while those at 20 % peaked (8.74 mu g TMP/g DW and 6.73 mu g SMX/g DW) after 5 h. TMP persisted in the tissues longer (up to 72 h) than SMX (12-16 h), suggesting a more efficient uptake and retention of the former and/or faster metabolism and elimination of the latter.