Recipient Organization
KENTUCKY STATE UNIVERSITY
(N/A)
FRANKFORT,KY 40601
Performing Department
Aquaculture
Non Technical Summary
It is now widely accepted that nutritional approaches are important to produce nutritionally balanced, cost-effective and environmentally friendly feeds for farmed aquatic animals. Largemouth bass (LMB; Micropterus salmoides) is a freshwater carnivorous teleost native to North America where its production as food fish has increased in recent years mainly due to increased output form U.S. farms. Because most of the nutritional requirements of LMB are still unknown, grow-out feeds for this species have consisted largely of high protein feeds formulated for salmonids, including rainbow trout and Atlantic salmon. Protein is the costliest component of aquaculture feeds and the increased utilization of protein feedstuffs with unbalanced amino acid profiles can lead to reduced protein utilization and increased nitrogen excretion to receiving waters as well as poor growth and feed efficiency of farmed fish. Amino acids (AAs) are the building blocks of protein and among the indispensable AAs (IAAs) required by fish, lysine (LYS), methionine, and threonine (THR) typically comprise the first three limiting IAAs in modern aquafeed formulations. Knowledge of the AA requirements of LMB is a premise to formulating AA-balanced feeds for this species, but information on its LYS requirement is limited and the THR requirement is lacking. Therefore, the objective of this project is twofold: (1) to refine the dietary LYS requirement of juvenile LMB and (2) to determine the dietary THR requirement of juvenile LMB.
Animal Health Component
30%
Research Effort Categories
Basic
60%
Applied
30%
Developmental
10%
Goals / Objectives
Our overall goal in this project is to increase aquaculture sustainability by providing the means by which aquaculture feeds are formulated with sustainable ingredients and are optimized to meet all nutritional requirements of farmed aquatic animals on a species-specific basis. To this end, our specific goals in this project are (1) to refine the dietary lysine requirement and (2) to determine the dietary threonine requirement of juvenile largemouth bass, Micropterus salmoides.If successful, this project will supply aquaculturists and the aquaculture feed industry with updated information on lysine and threonine requirements for optimum production performance of largemouth bass, a carnivorous fish species with increasing commercial importance in the United States as a food fish. Because both lysine and threonine are, typically, two limiting amino acids in modern aquaculture feed formulations, the estimated requirements will allow largemouth bass feeds to be optimized for limiting amino acids, thereby increasing feed efficiency and reducing the output of nutrients to receiving waters.
Project Methods
Standard procedures for amino acid requirement evaluations in fish will be used in this study. Two independent feeding trials will be conducted to assess the dietary lysine (LYS) and threonine (THR) requirements of juvenile largemouth bass (LMB). Each evaluation will follow a completely randomized design with six dietary treatments and three replicates per treatment.For each objective, a set of six semi-purified diets will be formulated and manufactured. These diets, originally deficient in LYS (Objective 1) or THR (Objective 2), will be gradually supplemented with crystalline LYS or THR so that the final concentration of these amino acids in the diets will range from deficient (below requirement) to excess (above requirement). Diets will be fed to groups of fish stocked in an aquaculture recirculating system for a period up to 12 weeks followed by data collection and computation, and statistical analyses to define specific requirements for LYS and THR. In order to express the dietary requirements on an availability basis, the digestibility of the basal diet (the diet not supplemented with crystalline sources of each amino acid in study) will be assessed in two separate evaluations. A detailed description of the methodology is provided in the proposal.