Although taurine has been identified as a required nutrient in several Seriola species, there are no available quantitative data on dietary taurine requirements for these commercially important species and recommendations are highly variable. Therefore, juvenile Seriola lalandi were fed one of eight practical diets supplemented with graded levels of taurine (0.11-1.08% of the dry diet, analyzed) to estimate their taurine requirement. Response in growth rate, feed efficiency, and nutrient deposition were evaluated using a broken-quadratic model and 4- and 5-parameter saturation kinetic models (4-SKM and 5-SKM) Blood serum composition was analyzed using linear models. Requirement estimates based on growth rates (thermal-unit growth coefficient) and protein deposition were similar at 0.26% (95% confidence interval [CI]: 0.23-0.28) and 0.29% (95% CI: 0.25-0.34) dietary taurine, respectively. Feed and protein deposition efficiencies were optimized at 0.26-1.02% and 0.26-1.00% dietary taurine, respectively. Taurine deposition in the animal was maximized at higher dietary levels (0.64%). Levels of serum taurine increased in response to dietary levels and peaked at around 0.80% dietary taurine. Concomitantly, serum urea and total amino acid levels decreased with increasing dietary taurine levels, suggesting a reduced amino acid catabolism relative to the aforementioned improvement in protein deposition efficiency.

Two trials were conducted to estimate the methionine (Met) requirement of juvenile white seabass, Atractoscion nobilis. Diets were formulated to contain 40% crude protein, 10% lipids, and 0.51% cysteine. Graded levels of dl‐Met were added to create seven diets with dietary Met levels ranging from 0.72 to 0.98%, and nine diets ranging from 0.64 to 1.28% Met in Trials A and B, respectively. Thermal‐unit growth coefficient was fitted to dietary Met levels to estimate the Met requirement using the saturation kinetic model (SKM), the quadratic model (QM), or the broken quadratic model (BQM). The 95% confidence interval (CI) was estimated through the iterative fitting process for the BQM and using a bootstrapping approach for the QM and SKM. In Trial A, the three models estimated the requirement between 0.88 and 1.08%, with wide CI. In Trial B, precisions of the requirement estimates by the SKM and BQM were significantly improved compared with Trial A, though BQM evidently overestimated the requirement. SKM provided the best fit; hence, we conclude that the Met requirement for juvenile white seabass is 0.88% (95% CI: 0.80–1.08%) in the presence of 0.51% cysteine. This estimate provides valuable basis for the formulation of practical diets for juvenile white seabass.

An 8-week feeding trial was conducted to determine the effectiveness of replacing fish meal (FM) with blends of alternative proteins in diets for white seabass (WSB, Atractoscion nobilis) at a starting weight of 5.6g. Five diets were formulated with 400-440gkg(-1) crude protein (380gkg(-1) digestible). These included a high 520gkg(-1) FM control diet, a series of three diets with a sequential replacement of FM containing 410gkg(-1), 510gkg(-1) and 630gkg(-1) of a soy-based protein blend (SPC) and 200gkg(-1), 100gkg(-1) and 0gkg(-1) FM, respectively and a fifth diet containing 550gkg(-1) of a corn-based protein blend (CGM) and 100gkg(-1) FM. Survival was highest in the FM control group at 99% but all other performance measures (weight gain, feed conversion ratio, specific growth rate and protein retention efficiency) were worse than the other treatment groups. Weight gain reached a maximum of 595% in the SPC 200gkg(-1) FM treatment group. Performance decreased as inclusion of the soy-based protein blend increased. The CGM treatment performed comparably to the SPC 100g kg(-1) FM treatment among all measures, except for survival, which was higher in the CGM 100gkg(-1) FM treatment. With nutrient levels and alternative protein blends used in this study, FM can be reduced to 100gkg(-1) of the diet for WSB without reductions in performance.

Interest in the commercial culture of White Seabass Atractoscion nobilis on the western coast of the United States has been increasing in recent years. Despite this interest, there is a scarcity of knowledge on the dietary requirements of this species, particularly as it relates to basic nutrient requirements and selection of feeds. Hence, we evaluated a wide range of protein levels (31, 34, 37, 40, 43, and 46%) with practical lipid levels (5.75, 7, 8.25, 9.5, 10.75, and 12%) to initiate the development of a species-specific commercial diet for White Seabass. A 56-d trial was conducted in a recirculating system at Hubbs-SeaWorld Research Institute's marine fish hatchery in Carlsbad, California. Diets were formulated to contain 20-30% fish meal and offered to juvenile White Seabass (3.6g mean initial weight). At the conclusion of the growth trial final weights ranged from 13.9 to 15.9g, and percent weight gain ranged from 278.2% to 345.6% and generally increased with protein level. Protein retention ranged from 25.2% to 33.7% and was significantly lower for fish offered the diets containing 43% and 46% protein. Based on growth and protein retention, the use of a diet incorporating 40% protein and 10% lipid is recommended for juvenile White Seabass. Received March 11, 2013; accepted August 17, 2013

A study was undertaken to examine the potential of two non-genetically modified (non-GM) soy products, differentially processed, as fishmeal (FM) replacements. Dietary protein (DP) was replaced at 50, 60 and 70% using the 3011 meal or 40, 50 and 60% with the 3032 meal. Ingredient 3011 was a cooked and solvent-extracted meal from a high protein and low oligosaccharide soy cultivar; whereas, ingredient 3032 was a cold-pressed, low fat cake ground to a meal that originated from a medium protein, low oligosaccharide, low protease inhibitor soy cultivar. Experimental diets were isonitrogenous (45% crude protein, CP), isolipidic (13% lipid), isocaloric (12.6kJ energy kg−1 of diet) and were balanced for lysine (3.2%) and methionine+cysteine (2%). Taurine was supplemented at 1.5% in all diets. A commercial control diet (52% CP and 13% lipid) was included for a total of eight test diets. Twenty four round tanks (330L) were each stocked with 20, 4g yellowtail (Seriola lalandi). Tanks were supplied with recirculated seawater and each diet was randomly assigned to three replicate tanks. After a 10-week feeding trial, growth, survival, feed conversion ratio, protein efficiency ratio, protein retention, condition factor and carcass proximate composition were contrasted among dietary treatments. Results indicate that juvenile yellowtail fed diets in which the 3032 meal provided 50 and 60% of DP grew significantly (P<0.001) better than those fed all other diets, including the FM-based (menhaden FM) and commercial control diets. Fish fed with the 3011 meal providing 50% of DP and those fed with the 3032 meal providing 40% of DP had similar growth performance which was slightly greater than the fish fed the FM reference diet. Minor intestinal histology differences were found among fish fed the 8 diets. Taken together these data indicates that the improved non-GM soybean meals supported better performance of juvenile yellowtail than fish fed the FM reference diet. No enteritis was detected even at high dietary inclusion levels.

Three trials were run to identify the limiting dietary amino acids in practical, soy-based formulations for California yellowtail juveniles. In the first trial, four diets were formulated with 20% fish meal and 43% soy protein concentrate. The basal diet was supplemented with methionine, lysine, and taurine (MLT), and each supplement was then individually deleted in three additional diets (LT, MT, and ML). A significant decrease in growth was only seen in fish fed the ML diet. The second and third trials were designed to test graded levels of dietary taurine and methionine, respectively. Dietary taurine ranged from 0.32 to 1.5%, and methionine levels ranged from 0.95 to 1.19% of the diet with constant levels of cysteine (0.73%). While weight gains were considered adequate to detect a dietary amino acid deficiency, there was no significant effect of graded levels of either taurine or methionine on final weights, growth rates, survival, or feed efficiency. In conclusion, the practical diets tested required taurine supplementations, but did not require lysine or methionine supplementation. While these data are insufficient to determine the taurine or methionine requirement of California yellowtail, it provides minimum levels likely to meet these requirements. Additional research is necessary to determine taurine and methionine requirements precisely in this species.

Two growth trials were designed to evaluate varying levels of taurine in diets for white seabass (WSB), Atractoscion nobilis. All diets were formulated to contain 40% protein and 10% lipid with a fixed level of fish meal (FM) and soybean meal (SBM). Trial A tested a series of six practical diets with 0.0, 0.1, 0.2, 0.3, 0.4, 0.5% taurine supplementation at the expense of glutamic acid, and a seventh diet with 0.5% cystine supplementation instead of taurine. Trial B was designed to test higher inclusion levels (0.2–1.6%) of taurine over six diets, while a seventh diet contained 1.6% taurine but no methionine supplement. In Trial A, the increased inclusion of taurine resulted in significantly improved final weight ranging from 14.6 to 26.6 g, TGC ranging from 0.074 to 0.120, and feed efficiency from 68.2 to 111.9%. The supplementation of cystine to the diet did not result in an improvement in growth, indicating the synthesis of taurine from cysteine decarboxylation is inadequate in WSB. Similarly, in Trial B significant improvements in performance were observed with increasing taurine supplements, albeit variation in the data was higher. Final weight ranged from 23.6 to 29.7 g, TGC ranging from 0.111 to 0.130 and feed efficiency from 75.6 to 81.4%. The diet with taurine supplement but without methionine showed a decrease in growth, suggesting that methionine was then limiting. Datasets from both trials were combined, and a saturation kinetics model was used to determine a dietary requirement of 0.99% of the diet (R2 = 0.8770). Based on these results, white seabass have a dietary requirement for taurine presumably due to a limited ability to synthesize it.

A feeding trial was conducted to study the effect of dietary lipid on growth performance and heat-shock protein (HSP70 and HSP60) response of white seabass (WSB), Atractoscion nobilis. Five diets were formulated to contain 440gkg1 protein from 300gkg1 fish meal, 240gkg1 soybean meal and 100gkg1 soy protein concentrate with different levels of lipid: 100, 120, 140, 160 or 180gkg1. At the end of the trial, heat shock response based on HSP70 and HSP60 was measured in liver and white muscle from fish at ambient temperature and temperature shock conditions. Final weight and percent gain were significantly higher for fish fed the 100gkg1 lipid diet than for fish fed the rest of the diets (P0.05). Feed conversion ratio was lowest for fish fed the 100gkg1 lipid diet. The HSP70 and HSP60 responses were positively correlated to dietary lipid levels following temperature shock. At ambient temperature, HSP60 and HSP70 responses in muscle and HSP60 response in liver increased with dietary lipid level. Temperature shock significantly increased the HSP response of fish in all treatments. Results of this study demonstrated that a moderate (110120gkg1) level of dietary lipids would be recommended for production diets but a higher dietary lipid level may be required for optimal stress tolerance.

The present study aims to identify the limiting amino acids in low fish meal, soy-based diets in juvenile white seabass. Two 8-week trials were conducted. The first trial evaluated three diets containing 36, 18 and 9% fish meal in the diet (FM36, FM18, FM9, respectively), with the last two diets being supplemented with methionine and taurine. In the second trial, seven diets were formulated, including a high (36%) fish meal diet (HFM, similar to FM36) and five diets with medium (18%) fishmeal levels. These included an unsupplemented diet (MFM) and four with increasing levels of methionine (+M, +2M) and taurine (+2MT and +2M2T) supplementation. An additional diet was formulated with soy protein and poultry by-product meal to completely replace fish meal (PM). In trial 1, fish fed the FM18 diet grew significantly faster than fish fed the FM36 and FM9 diets. In trial 2, fish fed the +2M2T diet grew better than fish fed any other diets, and feed efficiency was highest in fish fed the +2M2T and PM diets. Fish fed the unsupplemented MFM diet had the lowest growth and feed efficiency. Methionine supplementation (+M and +2M) had a limited but significant effect on growth performance compared to MFM-fed fish. Fish fed the PM diet showed similar growth as those fed the +2MT and commercial diets, but was lower than +2M2T diet. Across both trials, growth rate was highly correlated with dietary taurine, except in diets containing less than 18% fish meal, i.e., diets PM and FM9. Both of these diets had equivalent or superior dietary taurine levels compared to diets +2M2T and FM18, but resulted in significantly poorer growth. This suggests that taurine is the first-limiting nutrient in feeds containing at least 18% fish meal while methionine was marginally deficient. In diets containing lower levels of fish meal however, methionine and taurine supplementation is ineffective; hence another (undetermined) nutrient became first-limiting. Additional research is necessary to identify this limiting nutrient, as well as determine the specific taurine requirement of WSB.

Two feeding trials were conducted to initiate the development of a practical soy-based diet for California yellowtail (YT), Seriola lalandi. The first trial evaluated fish meal (FM), FM + solvent-extracted soybean meal (SBM) or FM + soy protein concentrate (SPC)-based diets and a commercial reference diet (Skretting Marine Grower). Final weights (31.8-67.6 g), per cent gain (492.8-1059.9%) and feed conversion ratio (1.11-1.59) all followed a similar response in that fish offered the commercial diet performed significantly better than fish maintained on the other diets. The second trial was designed to evaluate the replacement of FM with increasing levels of soy protein. The basal diet contained 400 g kg(-1) FM and 240 g kg(-1) SBM. The FM was then reduced to 300 g kg(-1), 200 g kg(-1) and 150 g kg(-1) of the diet using SPC as the replacement protein. Final weight (41.2-64.1 g) and per cent gain (110.5-226.5%) followed similar trends with decreases in performance as the FM level was reduced. No gross signs of enteritis were noted, indicating that reduced performance was likely due to nutrient deficiencies or palatability problems rather than an allergic response. Results demonstrate that there is potential to develop reduced FM diets for this species using soy protein.

Two feeding trials were conducted to begin development of a practical soy-based diet for white seabass Atractoscion nobilis. The first trial was designed to provide initial data on the efficacy of practical soy-based diets. Three diets and a commercial reference diet were evaluated. Research diets were 42% protein and 12% lipid, with varying protein sources: fish meal (FM), FM plus solvent-extracted soybean meal (SBM), or FM plus soy protein concentrate (SPC). Final weight (14.1-17.2 g), percent weight gain (307.2-401.8%), and feed conversion ratio (FCR; 1.0-1.2) followed similar trends, with fish offered the FM-based diet significantly outperforming the other dietary treatment groups. There was no significant difference between soy-based diets and the commercial reference diet, and no significant differences in survival due to dietary treatments were observed. The second trial was designed to evaluate varying levels of FM replacement with SPC in a series of four diets containing 42% protein and 12% lipid. The basal diet contained 40% FM and 24.6% SBM as primary protein sources. The FM was then reduced to 30, 20, and 15% of the diet using SPC as the replacement protein. Final weight (27.1-36.5 g), percent weight gain (69.0-116.6%), and FCR (1.5-2.4) followed similar trends, with performance decreasing as FM level was reduced. In general, each incremental reduction in FM resulted in significant reductions in final weight and percent weight gain and significant increases in FCR. Results from these initial trials on white seabass are encouraging because the poor response was most likely due to a nutrient imbalance or palatability problem, which can be corrected, as opposed to an allergic response. Given that the open formulations performed similarly to the commercial feed, these simple formulations can be used as a starting point for the development of practical diets for white seabass.

White seabass, Atractoscion nobilis, are important commercial and sport fish commonly found in Magdalena Bay, Baja California, Mexico to San Francisco Bay, California, USA (Thomas 1968). Adult white seabass inhabit the nearshore zone over rocky bottoms and kelp beds (Young 1973). White seabass can reach a size of 1.5 m and 38 kg (Miller and Lea 1972). Juveniles and young of the year are found in embayments and shallow water along the open coast (Allen and Franklin 1988a, b). White seabass are batch spawners typically spawning from April to August and congregate in rocky reef and kelp bed areas in the nearshore zone at this time (Thomas 1968). Eggs are approximately 1.3 mm in diameter and pelagic. Larvae are pelagic and are typical marine finfish larvae (Moser et al. 1983). Vision is important for feeding in most marine finfish larvae (Hunter 1980; Blaxter 1986). However, the eyes of marine finfish larvae at first feeding do not have illumination adaptation capability (Blaxter and Staines 1970; Neave 1984) and the development of the eye and visual acuity of white seabass, A. nobilis, is specifically known to be poor at first feeding (Margulies 1989). It is important to optimize environmental conditions in larviculture to facilitate feeding behavior (Tamazouzt et al. 2000). Maximization of feeding behavior should result in improved growth and survival (Downing and Litvak 1999b). Visually, this means maximizing contrast between food items and the environment making illumination in the larval rearing environment of primary importance. Illumination within a larval rearing tank can be affected by light source and intensity as well as tank color (Naas et al.

California sheephead are an important commercial and sport fish species in southern California. This study represents the first detailed description of spawning and patterns of egg production in a captive population of California sheephead. In March 2004, females ranged in size from 369 to 430 mm total length (TL) and weighed 0.8-1.5 kg. Males ranged in size from 475 to 510 mm TL and weighed 1.7-2.3 kg. Spawning began in April and continued daily through September and then sporadically through October. Egg production ranged from 1000 to 375,000 eggs/d, with an average of 130,000 eggs/d. Egg production peaked in May at 222,000 eggs/d and decreased throughout the remainder of the season. Total annual fecundity from this group was 1,942,000 eggs/kg female body weight. Egg viability ranged from 0 to 80% with an average of 50%. Viability showed a general increase at the beginning of the season and a decrease at the end of the season. Eggs were 0.9-1.0 mm in diameter and hatched in approximately 48 h at 18-19 C. Hatch rates showed a general decline throughout the season. This study shows that California sheephead will spawn readily in captivity providing thousands of viable eggs daily and lays the groundwork for culture of this species.

De la misma manera que la fuente inicial de nutrientes, la manipulacion del alimento es el medio mas directo y efectivo para reducir la carga de estos en los sistemas de cultivo intensivo. La eficiencia en la utilizacion alimenticia y el manejo no solo reducen la carga de nutrientes, sino ademas disminuyen el costo de produccion total al diminuir los gastos de nutrientes por unidad de produccion. Se han venido disenando investigaciones para desarrollar y evaluar dietas densas en nutrientes como un mecanismo para aumentar la produccion y reducir el desperdicio de productos. El efecto de las dietas nutricionalmente densas (proteina y energia) sobre el crecimiento de la curvina Scianus ocellatus y sobre la calidad del agua en sistemas de recirculacion cerrados han sido evaluados. Basandonos en los resultados observados, la manipulacion de la densidad dietaria de nutrientes puede reducir la carga de estos en los sistemas de cultivo, y al mismo tiempo mejorar el crecimiento de los peces. Estudios adicionales han evaluado los efectos de varios niveles de aceite de menhaden (MFO) y de trigliceridos de cadena mediana (MCT) como fuentes de energia en las dietas nutricionalmente densas. El mayor crecimiento y la mejor tasa de conversion alimenticia fueron observados en peces alimentados con dietas que no contenian MCT, y no se encontraron diferencias significativas entre la dieta basal que contenia 5.7% de lipidos y las dietas suplementadas con MFO adicional. La incorporacion de MCT en las dietas resulto en la reduccion de depositos de lipidos intraperitoniales, pero tambien redujo el desempeno del pez en terminos de ganancia en peso y de eficiencia de conversion alimenticia. En base a estos resultados la incorporacion de MCT puede contribuir a reducir el deposito intraperitonial de lipidos, y puede resultar apropiada para la evaluacion de dietas finalizadas. En funcion de los resultados presentes, el desarrollo de los alimentos nutricionalmente densos puede ayudar a reducir la carga de nutrientes en los sistemas de cultivo intensivo sin afectar adversamente los costos de produccion.

AbstractA series of growth trials was conducted to evaluate the use of soy protein as a replacement for fish protein in isonitrogenous practical diets for juvenile red drum Sciacnops ocellatus. Feeds were offered at or in excess of satiation to juvenile red drum maintained at 26–28 C and a salinity of 25–35 ppt. In the first growth trial, red drum were offered one of four diets containing graded levels of menhaden fish meal, replacing solvent‐extracted soybean meal and soy‐protein isolates. Differences in weight gain, survival and feed efficiency ratios of the fish corresponded to increases in fish meal content of the diets. Due to poor performance of the fish maintained on the low (15%) fish meal diet, a methionine supplement was introduced into this diet at the midpoint of the growth trial. A positive increase in growth indicated a dietary deficiency of methionine and/or total sulfur amino acids in the unsupplemented diet. A positive response to dietary fish meal also occurred in the second growth trial despite the supplementation of L‐methionine in the test diets. In low fish meal diets the utilization of solvent extracted soybean meal or a soy‐protein isolate resulted in similar growth responses. Hence, the presence of an antinutrient did not likely cause reduced growth rates. In the third feeding trial, weight gain also increased with increasing fish meal content of the diet despite the equalization of digestible protein and selected amino acids. There were no significant differences in whole‐body compositions which indicated similar biological value of the diets (protein digestibility, amino acid balance and energy availability). The singular deletion of fish‐solubles, glycine, lysine and methionine from the diet containing the lowest level of fish meal (10 g/100 g diet) did not result in significant changes in weight gain. This indicated that these components did not add to the nutritive value and/or palatability of this formulation. The final experiment was designed to evaluate the response of red drum to a control diet (high fish meal) as compared to a low fish meal diet with and without potential attractants/palatability enhancers. Weight gain and feed efficiency ratios of fish offered the low fish meal diet supplemented with seafood flavor or fish flavor #2 were not significantly different from the control (high fish meal diet). Based on the results of this study, with suitable formulation restrictions, soy protein is acceptable for inclusion in practical diet formulations for red drum. However, soy protein itself does not appear replete in sulfur‐containing amino acids and does not have acceptable palatability properties. Consequently, feeds containing reduced levels of marine proteins could require suitable attractants and/or amino acid supplements.