The Influence of Dietary Lysine on Yellow Perch Maturation and the Quality of Sperm

Abstract

AbstractThe objective of the present study was to determine whether lysine (Lys) supplementation influences the maturation and sperm quality of Yellow Perch Perca flavescens. Juveniles raised on a formulated commercial diet and weighing approximately 75 g each were randomly distributed into six 400‐L tanks. This experiment included two wheat‐gluten‐based diets in triplicate: (−) Lys (Lys‐deficient) and (+) Lys (Lys‐supplemented; 2.23% in dry feed) diets. In addition, 16 control fish were kept under identical conditions and fed a commercial diet. The weight of males was larger in the control group than in the (+) Lys and (−) Lys groups. The sperm concentration was significantly higher in the control and (+) Lys groups than in the (−) Lys group. Sperm motility was lower in the (−) Lys group than in the control and (+) Lys groups. The control group had significantly higher protein concentration in its seminal plasma than did the (+) Lys and (−) Lys groups. The seminal plasma trypsin inhibitor activity showed the same trend. The seminal plasma free amino acid concentrations of arginine, methionine, threonine, glutamine, alanine, and glycine differed significantly among treatments. This is the first report demonstrating the negative effect of dietary lysine level in plant‐protein‐based diets on reproduction in fish.