Lysine Requirements of Largemouth Bass, Micropterus salmoides: A Comparison of Methods of Analysis of Dose-Response Trials Data

ABSTRACT

Lysine is a strictly essential amino acid, the reference for dose-response trials to determine dietary amino acids requirements of fish. This study compares estimation of amino acids requirements of largemouth bass, Micropterus salmoides, from data of lysine dose-response trials, analyzed through different statistical methods: Polynomial regression analysis, broken-line regression analysis, and specific mathematical modeling. Amino acids requirements were estimated through the A/E relationship [A/E = (essential amino acid ÷ total essential amino acids + cystine + tyrosine) × 1.000]. Groups of 25 feed-conditioned largemouth bass fingerlings (1.29 ± 0.03 g; 4.35 ± 0.17 cm) were stocked in 60-L cages (5 mm mesh) housed in 1,000-L plastic, indoor tanks, closed circulation system, and fed diets containing 1.0, 1.5, 2.0, 2.5, 3.0, or 3.5% lysine, in a totally randomized experimental design trial (n = 4). The broken-line analysis method yielded more reliable and precise estimations of lysine requirements–2.1% of diet or 4.9% dietary protein–for final weight, weight gain, and specific growth rate. Best-feed conversion ratio was attained with 1.69% lysine in the diet or 3.9% lysine in dietary protein. Body amino acids profile was an adequate reference for estimation of largemouth bass amino acids requirements.

KEYWORDS:

• Lysine
• requirement
• largemouth bass
• Micropterus salmoides
• polynomial regression
• broken-line regression
• dose-response trial