Melanie A. Rhodes

Soy Protein Concentrate as an Alternative Ingredient in Florida Pompano (Trachinotus carolinus) Diets

Current research is intended to develop cost-effective, plant-based diets for intensive production of Florida pompano (Trachinotus carolinus). Three growth trials were conducted with juvenile pompano over a 106- to 115-day period. The trials evaluated the systematic substitution on an equal protein basis of (1) menhaden fish meal, FM with soy protein concentrate (SPC), and (2) solvent extracted soybean meal (SBM) with SPC. This confirmed the reduction of FM and evaluated the possible nutrient restrictions of methionine (M) and phosphorus (P) in low FM, high SPC diets. There was no significant reduction in growth parameters when FM was reduced from 300 to 150 g/kg. There was a significant improvement in fish performance with increased SPC concentrations substituted for SBM in diets containing 150 g/kg of FM. All growth parameters indicated a favorable response for inclusion of SPC up to 240 g/kg. The addition of P and M did not significantly improve growth.

Evaluation of the Ciliated Protozoa, Fabrea salina as a First Food for Larval Red Snapper, Lutjanus campechanus in a Large Scale Rearing Experiment

ABSTRACT One of the major challenges of culturing of red snapper, Lutjanus campechanus, is providing an appropriate food source at onset of feeding. Ciliates are abundant in marine waters but their significance as a first food for fish larvae is poorly understood as many have no lorica to facilitate their identification in the gut of a larval fish. Fabrea salina is a naked heterotrich ciliate that can be mass cultured at densities up to 84 ± 10 ciliates/mL in 7 days. Its appropriateness as a first food for red snapper larvae was evaluated in a green-water setting using 1-m3 tanks. Larvae were stocked at 10/L, 36 h post-hatch, before first-feeding commenced. Larvae were fed either (1) copepod nauplii, 20–75 μm, only from days 1 to 10; (2) copepod nauplii from days 1 to 10 plus F. salina from days 1 to 5; or, (3) F. salina only from days 1 to 3 plus copepod nauplii from days 4 to 10. Copepod nauplii were added at 2/mL and ciliates were added at 5/mL. Survival after 28 days was 0.28 ± 0.15% for larvae given only copepod nauplii and 2.39 ± 2.75% for those given F. salina and copepod nauplii. Larvae given only F. salina did not survive past 4 days post-stocking. Larvae were more actively feeding in the tanks given F. salina and copepods as first foods with 34.6 ± 8.5% mean daily reduction in copepod nauplii compared to 15.8 ± 16.2% reduction when only nauplii were provided.

Use of Dried Fermented Biomass as a Fish Meal Replacement in Practical Diets of Florida Pompano, Trachinotus carolinus

Substitution of fish meal (FM) as a protein source in aquaculture diets is required to reduce cost and promote a sustainable industry. Potential protein sources include a range of traditional products from agricultural production such as plant or animal proteins. However, there are also a number of manufacturing coproducts, including bacterial dried fermented biomass (DFB,) for which there is an increased interest. Hence, the objective of this study was to evaluate DFB as a replacement for FM in practical diets for Florida pompano, Trachinotus carolinus. Four diets were prepared in which different levels of FM (15%, 10%, 5%, and 0% of the diet) were replaced with DFB (0%, 4.27%, 8.54%, and 12.82%) on an iso-nitrogenous and iso-lipidic basis, to contain 40% crude protein and 10% lipid. A 10-week growth trial was conducted in a recirculating system consisting of 12 indoor 1.0 m3 tanks, stocked with 20 juvenile pompano (mean initial weight 8.1 g) per tank. There were no significant differences in final weight (64.5 g−79.5 g), survival (81.7%–96.7%), percent weight gain (711.6%–879.0%), FCR (2.1–2.0), or thermal-unit growth coefficient (0.1013−0.1149), regardless of the levels of dietary FM or DFB tested. Based on these results, it is recommended that DFB can be included up to 12.8% in practical diets for Florida pompano without significantly reducing growth performance. The response to higher levels of DFB inclusion should be evaluated.

Use of Lipid-Extracted Distillers Dried Grain with Solubles (DDGS) in Diets for Pacific White Shrimp

AbstractA series of trials (one growth trial and two digestibility trials) were conducted to evaluate the response of Pacific white shrimp Litopenaeus vannamei to the inclusion of lipid-extracted distillers dried grain with solubles (LE-DDGS). In the growth trial, a practical basal diet was developed for shrimp using soybean meal (56.76% diet) and fish meal (6% diet) as the primary protein sources. The LE-DDGS was substituted for soybean meal on an isonitrogenous basis at five levels of inclusion (0, 10, 20, 30, and 40%) with lysine supplemented to diets containing 30% and 40% LE-DDGS. A sixth diet containing 40% LE-DDGS but without a lysine supplement was also evaluated. The diets were offered to four replicate (15 shrimp/tank) groups of shrimp per treatment over an 8-week growth trial. At the end of the growth trial shrimp offered diets containing from 0% to 20% LE-DDGS performed similarly. Performance of shrimp fed higher levels of LE-DDGS was reduced but similar to each other. Removing the lysine supp...