Progress 10/01/04 to 09/30/08
Outputs
OUTPUTS: It was hypothesized that growth and survival of larvae could be affected by feeding larval diet with hydrolysate prepared by different degrees of hydrolysis. The degree of hydrolysis should be gradually lessened with the phase of larval growth as larvae develop a gut and are able to digest more complex proteins. As an one-year extension to our previous project - Innovative aquaculture feed development for fish meal replacement, we examined if the extent of hydrolysis will affect the feed performance of squid hydrolysate (SH)-based diet on cod larvae at the different phase of growth. Squid hydrolysates (SH) of two different degrees of hydrolysis were thus prepared from squid processing byproduct (SPB) at 1 and 2 h at 55 C and incorporated into microparticulate diets as a sole protein source (73% of the whole diet; 56.4% protein, 24.7% lipid, 7.3% carbohydrate and 19.97 MJ/kg, on a dry weight basis). Microdiets were prepared using drum and plate drying and micronized to 300 um and 500 um. Atlantic cod (Gadus morhua) larvae of 30 d.a.h. previously fed rotifer and Artemia were brought into aquaria at 10 C (20 fish each in triplicate) and acclimated for 2 wk with DHA-enriched Artemia. Thereafter, larvae were on 3 different microdiets for 6 wk including Artemia for initial 3 wk as a control. Based on the initial 3 wk feeding trial, the growth performance on microdiets was comparable to that on the Artemia control. After a 3 wk feeding period, Artemia was not able to support the normal growth as larvae passed the weaning phase. The growth performance was assessed in terms of body weight (BW), body length (BL), body condition factor (BCF) and specific growth rate (SGR). For 6 wk feeding, 63-68% of larvae survived through the weaning period. No significant differences (p > 0.05) in all parameters studied for growth performance among microdiets prepared with SH of different degrees of hydrolysate (1 h, 2 h hydrolysis and 2h hydrolysis diet followed by 1h hydrolysis diet). This suggests that 1h hydrolysis was sufficient for SH to be digestible to larvae and no added benefits are expected from extended hydrolysis. In addition, a two-stage feeding regimen with 2 h SH diet (more hydrolyzed and lower m.w. peptides) followed by 1 h SH diet (less hydrolyzed and higher m.w. peptides) did not demonstrate expected benefits as hypothesized. PARTICIPANTS: Chong Lee and David Bengtson, co-principal investigators, Barry Volson, Kate Lankin and Sebnem Tolasa are graduate students who worked on the project and therefore received training in conducting nutrition experiments. TARGET AUDIENCES: Fish feed manufacturers, the finfish aquaculture industry, and other scientists working on fish nutrition, as well as the United Soybean Board. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
When the protein-hydrolysate diet was used, the growth performance of larvae could be affected by different degrees of hydrolysis. It was suggested that the degree of hydrolysis should be gradually lessened with the phase of larval growth as larvae develop a gut and are able to digest more complex proteins. However, in our squid hydrolysate (SH)-based microdiet study, 1h hydrolysis was sufficient for SH to be digestible to larvae and no added benefits were observed from extended hydrolysis. In addition, a two-stage feeding regimen with 2 h SH diet (more hydrolyzed and lower m.w. peptides; less complex proteins) followed by 1 h SH diet (less hydrolyzed and higher m.w. peptides; more complex proteins) did not demonstrate expected benefits as hypothesized.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: We conducted a 12-week experiment to further investigate replacement of fish meal (FM) with soybean meal (SBM) in diets for summer flounder. The experiment consisted of nine treatments, using SBM at 40% or 70% replacement of FM: 1) FM (control), 2) 40% plus amino acids, 3) 40% plus taurine, 4) 40% plus phytase, 5) 40% plus taurine and phytase, 6) 70% plus amino acids, 7) 70% plus taurine, 8) 70% plus phytase, and 9) 70% plus taurine and phytase. Fish showed maximum growth on 40% plus taurine, significantly greater than all other diets except 40% plus amino acids and 40% plus taurine and phytase, while the FM diet was not significantly different from 40% plus amino acids, 40% plus phytase, or 40% plus taurine and phytase. Fish growth on all 70% replacement diets was significantly less than on all the FM or 40% replacement diets, but no significant differences existed within the suite of 70% replacement diets. Thus, better growth was achieved on 40% SBM plus taurine than on FM
alone, suggesting that summer flounder production costs can be reduced by partial replacement of FM with SBM. We presented results of this and previous research at Aquaculture 2007 in San Antonio, TX (26 Feb-2 Mar 2007) and at the 3rd International Sustainable Marine Fish Culture Conference in Ft. Pierce, FL (13-15 Oct 2007). The results presented in FL were reported by Fish Farming News, so they were widely disseminated to industry. We also provided the abstract for the FL meeting to the United Soybean Board, which is engaged in outreach to the aquaculture industry.
PARTICIPANTS: Barry Volson, Kate Lankin and Sebnem Tolasa are graduate students who worked on the project and therefore received training in conducting nutrition experiments.
TARGET AUDIENCES: Fish feed manufacturers, the finfish aquaculture industry, and other scientists working on fish nutrition, as well as the United Soybean Board.
Impacts
Our findings add to the body of knowledge that taurine can be a major additive factor in improving diets in which fish meal has been replaced, in whole or in part. The results allow us to plan new experiments and generate new proposals for funding to see if we can replace more fish meal with higher levels of taurine added. Comparison of our results to those of other studies suggests that there are likely to be species-specific differences (among fish species fed the diets) in the ultimate amount of fish meal replacement with soybean meal that can be accomplished.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
The objectives of our work were to develop plant protein-based aquaculture feeds prepared with soy, corn gluten and canola protein concentrate and evaluate their feeding performance using regionally important aquaculture species, summer flounder and Atlantic cod. The 1st study involved the comparison of three major plant protein sources for fish meal replacement on juvenile summer flounder (15 g, 10 cm; 8-week feeding). Soybean meal (SBM), corn gluten meal (CGM) and canola protein concentrate (CPC) were substituted at 0, 20, 30, 40 and 50% levels with essential amino acids supplemented and 1% betaine as feed attractant. The fish meal diet showed significantly lower feed conversion ratio (FCR) and higher specific growth rate (SGR) and protein efficiency ratio (PER) than all plant proteins even at 20% replacement level. Results indicate that feed attractant and amino acid supplementation may not be enough to overcome the poor performance of plant proteins when used
singly. In the 2nd study, we assessed the feeding performance of plant proteins at 40% replacement level in the form of multi-protein combination (SBM, CGM and CPC) with and without amino acids (AA), phytase and taurine supplementation using juvenile summer flounder (33.81 g; 11.73 cm; 8-week feeding), 10 fish each in triplicate. Diets (48-50% protein; 11-13% lipid) included fish meal (FM 75% level), SBM (45% FM-30% SBM) with AA (Arg, Lys, Met, Thr), SBM-CGM-CPC blend (SCC) (45% FM-15% SBM-11.3% CGM-3.8% CPC on a feed weight basis or 60% FM-20% SBM-15% CGM-5% CPC on a protein ingredient weight basis) with and without AA. SCC with phytase (0.2%) or taurine (1%) without AA supplemented, and SCC with AA, phytase and taurine. The body composition analysis revealed that there was no appreciable variation in protein (14.6-15.0 %; 1.1% variability). Results suggest that the multi-plant protein blend outperformed SBM, and its performance can be further improved with AA, phytase and taurine
supplementation. Taurine appears to be most effective in enhancing feed consumption and growth when used with a multi-plant protein blend. The cost of taurine supplementation is estimated to be lower ($30/ton feed) than $36 for SBM and $45 for SCC. In the 3rd study, we evaluated the feeding stimulant effect of squid hydrolysate (SH) in view of its known feed attractant properties and potential commercial availability from the abundant source of raw material. Diets studied included FM, SBM (40% FM replacement) and SBM-SH (40%-5% FM replacement) with AA supplemented, but without betaine using juvenile summer flounder (7.15 g; 9.22 cm; 5-week feeding). SH at 5% addition resulted in FCR (0.99 wet feed; 0.29 dry feed), PER (2.52) and SGR (2.66) comparable to FCR (0.90 wet feed; 0.28 dry feed), PER (2.59) and SGR (2.64) of FM. SBM, on the other hand, showed a higher FCR (1.07 wet feed; 0.32 dry feed) and lower PER (2.37) and SGR (2.50). These results suggest that addition of SH could
improve the overall performance of SBM-based feed for juvenile summer flounder. SH showed a good feeding performance on summer flounder larvae of 17 DAH.
Impacts
The aquaculture feed formulation strategy with a multi-plant protein blend approach with amino acids, phytase, taurine and squid hydrolysate supplementation will help enhance the economic opportunities for the U.S. aquaculture industry by reducing production cost with a better access to alternative ingredients to fish meal. The Northeast aquaculture industry is currently using squid hydrolysate as a broodstock nutrition enhancer for cod and barramundi with positive results.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Fish meal is the primary protein source used in diets for piscivorous fish in aquaculture, but it is expensive and its use has been criticized by environmental groups, because it relies on removal of fish from the sea to feed other fish in captivity. We are trying to replace fish meal in diets for summer flounder with plant proteins and a hydrolysate made from waste materials from squid processing plants. We report here on the first year of this project. We first constructed a facility for testing the diets with juvenile summer flounder; it includes temperature-controlled, flow-through filtered seawater to a system of forty-five 75-L glass aquaria, so that multiple diet trials can be run simultaneously with adequate replication. We then formulated and manufactured diets based on replacement of fish meal with soybean meal, canola protein concentrate and corn gluten meal, each of which was used to replace fish meal at levels of 0, 20, 30, 40, or 50% replacement. Diets
were formulated to be 50% protein and 10% lipid. The experiment was run as a 3 x 5 factorial design with protein type (soy, canola, corn) and replacement level (0, 20, 30, 40, 50) as the main factors. Experiment duration was 8 weeks and fish were measured and weighed every 4 weeks. With the exception of one replicate that was lost due to system failure, no mortalities were observed during the experiment. No significant differences in growth were found among protein types (i.e., soy, canola and corn all produced similar results). The control diet (0% replacement of fish meal) yielded significantly better growth of fish than any of the diets with plant protein included and the diets with 50% replacement of fish meal yielded significantly worse growth than those with 20, 30 or 40% replacement. There was no significant interaction between protein type and replacement level. At the end of the experiment, fish from each replicate aquarium were pooled, homogenized and analyzed for content of
moisture, ash, lipid and (by subtraction) protein. While some statistically significant differences were observed, they were not considered to be biologically or chemically significant, especially since no consistent trends were observed in the data. Interestingly, despite the lower growth rate of fish fed plant protein, the 30% and 40% soy replacement diets provided growth at an 11% lower cost per kg of fish produced. The next step in the research (year 2) is to try to improve the performance of plant protein replacement diets by adding squid hydrolysate to them.
Impacts
We expect that our research will lead to lower production costs for summer flounder in aquaculture. The development of this industry in the U.S. has been hampered by high production costs and improvements in a number of areas, including feed costs, are necessary for the industry to develop.
Publications
- Lian, P.Z., C.M. Lee and E. Park. 2005. Characterization of squid-processing byproduct hydrolysate and its potential as aquaculture feed ingredient. J. Agric. Food Chem. 53: 5587-5592.
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