Progress 05/15/01 to 05/14/04
Outputs
The culture potential of two species of dinoflagellates and their value as a first food for red snapper larvae were evaluated. The growth characteristics of Gyrodinium and Gymnodinium were evaluated under conditions of 13 hrs. light/11 hrs. dark in flasks of 250 mL to 1 L using L/1 nutrients. In general, Gymnodinium appeared to be the more robust species for culture and was the focus of additional studies. Healthy flasks of Gymnodinium have regular density increases of 40-55%/week, reaching a maximum density (~10000-14000 cells/mL). Eight 700 L tanks in a greenhouse were filled with filtered seas water. For the first 4-d after stocking snapper larvae, four tanks received Gymnodinium at 20/mL and copepod nauplii at 2/mL and four tanks rotifers at 2/ml along with copepod nauplii at 2/ml. After the first 4-d all tanks continued to receive nauplii but not Gymnodinium or rotifers. Larval survivals were similar for both treatments through day-5 post-stocking, with only one
tank producing juvenile fish. Thirty-four different bacteria were initially isolated from the intestine of adult red snapper. Five of the 30 isolates screened from red snapper or larval rearing water showed some probiotic inhibition of one or more of the Vibrio species evaluated. Three commercial diets (Biokyowa, INVE, Salt creek) were evaluated for weaning young snapper from live foods to formulated diets. All three diets resulted in fish being successfully weaned over to a dry formulated diet. Brood snapper were held in temperature /photoperiod controlled tanks to obtain natural spawning. Temperature and photoperiod was adjusted to follow the natural cycle for the area. Fish were held at less than 16 C for 31 days, 115 days at 16 to 19C, 71 days at 20 to 24C, and 90 days at 25C+. A total of 38 egg releases were obtained from three of the six tanks from May 12 to July 24. The majority of the egg releases were unfertilized. Eleven spawns contained fertilized eggs with the percent
fertilization ranging from less than 50% to greater than80%. The number of eggs collected per egg release ranged from under 25,000 to more than 130,000. There was no pattern is frequency of spawning. Total lipid content and fatty acid composition of red snapper ovaries from wild caught red snapper, red snapper fed an enriched diet, and red snapper fed a control diet were compared. Differences in total lipid and fatty acid composition were also examined between red snapper eggs from fish fed an enriched diet that spawned naturally in photoperiod tanks and wild caught fish that were induced to spawn with human chorionic gonadotropin. There were no significant differences in total lipid content among red snapper ovaries, or between red snapper eggs. The neutral lipids for wild red snapper ovaries contained significantly larger amounts of linoleic acid , linolenic acid , AA , and DHA . This same trend was seen in the polar lipids, while AA was the only fatty acid that was significantly
higher in wild fish. Neutral and polar fatty acids were not significantly different between wild caught fish that were induced to spawn and captive fish that were fed a diet enriched with menhaden oil.
Impacts
The improved understanding of the nutrient composition of red snapper ovaries and eggs will help facilitate its successful culture. Techniques for environmental control have been developed that will allow natural spawning to occur under a controlled setting. Development of alternative first foods for red snapper larvae will improve overall larval survival. Development of such foods will also facilitate the culture of other difficult to culture marine fish larvae. Egg quality can be improved by allowing natural vs. induced spawns. The isolation of probiotic bacteria that control the growth of Vibrio can help reduce the significance of Vibrio infections in red snapper. Continued effort will be required to understand the nutrient requirements of first feeding red snapper larvae to be able to improve its survival during the first few days after hatching.
Publications
- Bueno, Fabricio T. 2002. Fecundity estimation and induced spawning of red snapper Lutjanus campechanus. MS thesis, Auburn University.
- Williams, Kresimir, 2002. Development of yolk-sac larvae of red snapper, Lutjanus campechanus, and the effect of temperature. MS thesis, Auburn University.
- Maxwell, Vanessa J. 2003. Probiotic potential in red snapper Lutjanus campechnaus larviculture. MS thesis, Auburn University
- Papanikos, N., R.P. Phelps, K. Williams, A. Ferry and D. Maus. 2003. Egg and larval quality of natural and induced spawns of red snapper, Lutjanus campechnaus. Fish Physiology and Biochemistry 28:487-488.
- Ross, Michael.2003. Lipid and fatty acid composition of red snapper, Lutjanus campechnaus, ovaries nad eggs. MS thesis, Auburn University
- Sumiarsa, Gede Suwarthama. 2003. Production And Fatty Acid Profiles Of Cyclopoid Copepod Nauplii Apocyclops panamensis. Doctoral dissertation, Auburn University
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Progress 01/01/03 to 12/31/03
Outputs
The culture potential of two species of dinoflagellates and their value as a first food for red snapper larvae were evaluated. The growth characteristics of Gyrodinium and Gymnodinium were evaluated under conditions of 13 hrs. light/11 hrs. dark in flasks of 250 mL to 1 L using L/1 nutrients. In general, Gymnodinium appeared to be the more robust species for culture and was the focus of additional studies. Healthy flasks of Gymnodinium have regular density increases of 40-55%/week, reaching a maximum density (10000-14000 cells/mL). Eight 700 L tanks in a greenhouse were filled with filtered seas water. For the first 4-d after stocking snapper larvae, four tanks received Gymnodinium at 20/mL and copepod nauplii at 2/mL and four tanks rotifers at 2/ml along with copepod nauplii at 2/ml. After the first 4-d all tanks continued to receive nauplii but not Gymnodinium or rotifers. Larval survivals were similar for both treatments through day-5 post-stocking, with only one
tank producing juvenile fish. Thirty-four different bacteria were initially isolated from the intestine of adult red snapper. Five of the 30 isolates screened from red snapper or larval rearing water showed some probiotic inhibition of one or more of the Vibrio species evaluated. Three commercial diets (Biokyowa, INVE, Salt creek) were evaluated for weaning young snapper from live foods to formulated diets. All three diets resulted in fish being successfully weaned over to a dry formulated diet. Brood snapper were held in temperature /photoperiod controlled tanks to obtain natural spawning. Temperature and photoperiod was adjusted to follow the natural cycle for the area. Fish were held at less than 16 C for 31 days, 115 days at 16 to 19C, 71 days at 20 to 24C, and 90 days at 25C+. A total of 38 egg releases were obtained from three of the six tanks from May 12 to July 24. The majority of the egg releases were unfertilized. Eleven spawns contained fertilized eggs with the percent
fertilization ranging from less than 50% to greater than80%. The number of eggs collected per egg release ranged from under 25,000 to more than 130,000. There was no pattern is frequency of spawning. Total lipid content and fatty acid composition of red snapper ovaries from wild caught red snapper, red snapper fed an enriched diet, and red snapper fed a control diet were compared. Differences in total lipid and fatty acid composition were also examined between red snapper eggs from fish fed an enriched diet that spawned naturally in photoperiod tanks and wild caught fish that were induced to spawn with human chorionic gonadotropin. There were no significant differences in total lipid content among red snapper ovaries, or between red snapper eggs. The neutral lipids for wild red snapper ovaries contained significantly larger amounts of linoleic acid , linolenic acid , AA , and DHA . This same trend was seen in the polar lipids, while AA was the only fatty acid that was significantly
higher in wild fish. Neutral and polar fatty acids were not significantly different between wild caught fish that were induced to spawn and captive fish that were fed a diet enriched with menhaden oil.
Impacts
The improved understanding of the nutrient composition of red snapper ovaries and eggs will help facilitate its successful culture. Techniques for environmental control have been developed that will allow natural spawning to occur under a controlled setting. The isolation of probiotic bacteria that control the growth of Vibrio can help reduce the significance of Vibrio infections in red snapper. Continued effort will be required to understand the nutrient requirements of first feeding red snapper larvae to be able to improve its survival during the first few days after hatching.
Publications
- Maxwell, Vanessa J. 2003. Probiotic potential in red snapper Lutjanus campechnaus larviculture. MS thesis, Auburn University
- Sumiarsa, Gede Suwarthama. 2003. Production and fatty acid profiles of cyclopoid copepod nauplii Apocyclops panamensis. Doctoral dissertation, Auburn University
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Progress 01/01/02 to 12/31/02
Outputs
Differences in total lipid content and fatty acid composition of red snapper ovaries from wild caught red snapper, red snapper fed an enriched diet, and red snapper fed a control diet were studied. Differences in total lipid and fatty acid composition were also examined between red snapper eggs from fish fed an enriched diet that spawned naturally in photoperiod tanks and wild caught fish that were induced to spawn with human chorionic gonadotropin. There were no significant differences in total lipid content among red snapper ovaries, or between red snapper eggs. The neutral lipids for wild red snapper ovaries contained significantly larger amounts of linoleic acid (18:2n - 6), linolenic acid (18:3n - 3), AA (20:4n - 6), and DHA (22:6n - 3). This same trend was seen in the polar lipids, while AA was the only fatty acid that was significantly higher in wild fish. Neutral and polar fatty acids were not significantly different between wild caught fish that were induced
to spawn and captive fish that were fed a diet enriched with menhaden oil. Red snapper brooders were fed a control diet consisted of the raw ingredients that were ground and mixed with hot water and gelatin as a binder. The enriched diet was similar to control plus menhaden oil and a vitamin and mineral premix.. The control diet group had better reproductive performance. The control diet group gave 63 spawns while the enriched diet group gave 22 spawns. Mean egg production was 4.2 and 0.4 million eggs for the control and the enriched diet groups respectively (Fig 1). Fertilized spawns, larger than 50,000 eggs, were received from both treatments, 22 from the control and just one from the enriched treatment. The mean fertilization rate, the hatch rate and the survival at 36-40 hph were 90.5%, 83% and 49% respectively for the control treatment. The above parameters for the one fertilized spawn of the enriched diet group were 99%, 87% and 70. Thirty-four different bacteria were isolated
from the adult red snapper representing various species including the pathogen Vibrio parahemalyticus. Fourteen isolates of gram positive bacteria were obtained from the water source along with an additional fourteen Vibrio sp. Four of the isolates showed a probiotic effect with some measurable inhibition to one or more of the Vibrio species. The addition of rotifers in the diet of first feeding red snapper did not improve larval survival. Critical development of red snapper larvae from hatching to first feeding was monitored using three temperature treatments. 24, 26 and 28 C until mouth part articulation. Oil globule utilization appears to be most efficient relative to growth at 28 C, with the largest percentage of oil globule remaining at the time of mouth part articulation.
Impacts
The combination of first feeds and larval rearing conditions is essential to establishing protocols that will lead to the reliable, repeatable production of red snapper
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
A series of trials were conducted to determine the culture potential of two species of dinoflagellates and their value as a first food for red snapper larvae. In general, Gymnodinium appeared to be the more robust species for culture and was the focus of additional studies. Healthy flasks of Gymnodinium have regular density increases of 40-55%/week. Contamination is not a major problem with Gymnodinium although once a culture has reached a maximum density (10000-14000 cells/mL) they begin to die off. Gyrodinium growth rates were much lower, with typical density increases from 0-30%/week. Gyrodinium flasks always have dark matter collected on the bottom or flask (presumably dead cells) and this becomes contaminated after a week if the culture is not transferred to a clean flask. Healthy Gymnodinium can be expected to double in density in one week's time. Temperatures in the stock culture room have ranged from 23-30 C with no apparent effect on growth rates, although
optimum temperature is likely less then 28 C. A photoperiod is necessary for Gymnodinium to thrive. A cycle with 13 hours of light has produced high growth rates with densities doubling in one week's time. Initial stocking densities should not be lower then 2000 cells/mL. The maximum density that a flask or bag of Gymnodinium reaches before they begin to die off is between 10,000-14,000 cells/mL. At that point the culture needs to be transferred to a clean flask and diluted with fresh media. The role of bacteria in influencing the survival of red snapper larvae was considered from several perspectives. Two trials were conduced to determine the typical aquatic bacterial flora that might be associated with larval rearing tanks and their relationship to fish survival. Snapper larval survival was poor, with the vast majority dying before the end of the five-day trial. The level of colony forming units/mL (bacterial cells in sample) varied between the tanks and within the tanks over time.
A second study was conducted to compare the impact of three different tank management methods on microbial levels using four replicate tanks per treatment. No manage practice gave a significant difference in bacterial counts, Larval mortality was rapid and only one tank had fish survival on day-5. No correlation of bacterial counts or water quality to fish survival was observed. Wild snapper were captured and 34 aerobic and anaerobic bacteria were isolated from the intestinal tract. These bacterial isolates have been held in culture and will be evaluated as to their potential as probiotics.
Impacts
The combination of first feeds and larval rearing conditions is essential to establishing protocols that will lead to the reliable, repeatable production of red snapper
Publications
- No publications reported this period
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