Comparative study on the utilization of different lysine sources by channel catfish (Ictalurus punctatus)

In this study, five diets were formulated, namely positive control, negative control (lysine deficient) without or with the addition of crystalline l-Lys·HCl, l-Lys·H2SO4 and microcapsulated l-lysine·HCl (M-Lys), and then fed to channel catfish with an initial body weight of 76.0 ± 0.3 g to investigate the effects of various lysine sources on the growth. After 8-week feeding, the fish fed M-Lys diet, but not Lys·HCl or Lys·H2SO4 diet, had a higher weight gain, a higher protein retention ratio and a lower feed conversion ratio than that fed negative control (P