Publication Date

2016-07-25

Availability

Open access

Embargo Period

2016-07-25

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Marine Affairs and Policy (Marine)

Date of Defense

2016-07-01

First Committee Member

Daniel D. Benetti

Second Committee Member

Jorge A. Suarez

Third Committee Member

Delbert M. Gatlin III

Abstract

Replacement of fishmeal with soy-based protein alternatives has produced the need to determine nutritional requirements of aquaculture species to appropriately formulate and supplement aquafeeds. Compared to fishmeal, soybean meal is deficient in methionine, an essential amino acid. Thus, the methionine requirement of a high-value and soy-tolerant species, the Florida pompano (Trachinotus carolinus) at a near harvestable size (>200 g) was evaluated. Six semi-purified, isonitrogenous and isocaloric, experimental diets were formulated based on the whole-body amino acid (AA) profile of the Florida pompano with incremental inclusions of methionine (0.5, 0.7, 0.9, 1.1, 1.3, and 1.5 g 100 g diet–1). Three tanks were randomly assigned per diet and stocked with 11 fish per tank averaging a total of 2290.3 ± 13.86 g initial biomass. Fish were fed twice daily at 900 h and 1500 h to satiation for 58 days. Pompano from all treatments, including the lowest and highest inclusions of methionine exhibited normal behavior, appearance, and weight gain throughout the duration of the experiment. There were no discernible trends (neither increasing nor decreasing) among growth parameters across all methionine inclusion levels. No significant differences (p > 0.05) were observed among treatments for mean daily intake (MDI), weight gain ratio (WGR), specific growth rate (SGR), energy intake (EI), protein intake (PI), feed efficiency (FE), and hepatosomatic index (HSI). Significant differences were apparent (p < 0.05) for average weight gain (AWG), average daily gain (ADG), protein efficiency ratio (PER), and feed conversion ratio (FCR) with substandard values for fish fed Diet 4 (1.1 g 100 g diet–1) compared to the other diets. These results suggest that near-harvestable size Florida pompano perform well with respect to growth at the lowest methionine inclusion of 0.5 g / 100 g diet. Further research is required to confirm these findings.

Keywords

Florida pompano; methionine; requirement; fishmeal replacement; soybean meal

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