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

Abstract

In this study, five diets were formulated, namely positive control, negative control (lysine deficient) without or with the addition of crystalline L-LysÁHCl, L-LysÁH 2 SO 4 and microcapsulated L-lysineÁHCl (M-Lys), and then fed to channel catfish with an initial body weight of 76.0 AE 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 LysÁHCl or LysÁH 2 SO 4 diet, had a higher weight gain, a higher protein retention ratio and a lower feed conversion ratio than that fed negative control (P < 0.05), and showed a similar growth as positive control. The serum free amino acid level of LysÁHCl and LysÁH 2 SO 4 group reached the plateau at the 2nd h after feeding, while the other three groups peaked at the 4th h. In LysÁHCl and LysÁH 2 SO 4 groups, the activities of liver aspartate aminotransferase and alanine aminotransferase peaked at the 2nd h, but M-Lys group peaked at the 6th and 4th h after feeding, respectively. The above results indicated that the supplementation of M-Lys rather than LysÁHCl or LysÁH 2 SO 4 in lysine-deficient diet could improve the growth performance of channel catfish, due to the delayed absorption of supplemental lysine.

Lysine requirements of tambatinga (♀ Colossoma macropomum × ♂ Piaractus brachypomus ) fingerlings using different diet formulation techniques

“…The ideal protein concept has been proposed for the formulation of experimental diets. This consists of using a balance of essential amino acids in ideal proportions or in function on a reference amino acid, the lysine (Abimorad et al, 2014;Hua et al, 2019;Rahimnejad & Lee, 2014;Zhao et al, 2016). Lysine is the essential amino acid found in the greatest proportion in the muscle tissues of fish, serves as the precursor of carnitine, which acts as a carrier of long-chain fatty acids into the mitochondria for β-oxidation, and is one of the most limiting amino acids in diets based in ingredients plant origin.…”