News & Views Nutrition & Feed products Research
Feed for juvenile leopard coral grouper gets a lift from China lysine study

Optimal lysine requirement in juvenile leopard coral grouper was identified by a research team in China. Compared to other ratio in diets used, inclusion of 2.60 to 2.97 per cent, with 4.9 to 5.60 of dietary protein) improved WGR, FCR and lysine deposition.

The breakthrough is expected to contribute to the production of specialized compound feed for leopard coral grouper, which, prior to study was not possible because of limited information on animal nutritional requirements.

“Effects of Dietary Lysine Level on Growth Performance and Protein Metabolism in Juvenile Leopard Coral Grouper (Plectropomus leopardus)”, published on Aquaculture Nutrition, is the first study to research on the lysine requirement in the animal, said authors, Xiaomei Dou et al.

Leopard coral grouper feed formulation is much needed in China, where the species is in high demand. “Due to its good flavour and bright body colour, P. leopardus is popular and marketable in China. The decline of wild resources and relatively slow growth rate have led to the increasing price of P. leopardus,” they said.

Lysine inclusion in juvenile grouper diet is a tight rope act.

This alkaline amino acid plays an important role in the normal growth and development of fish. Too little a dosage causes decrease in appetite and feed intake, hampering growth and development in animals.

Too much also has its repercussions. Growth and health are compromised “as it disrupts the balance of amino acids and prevents the absorption and utilization of other amino acids.”

The National Research Council of the National Academies, based in the US, lysine requirements of freshwater and marine fishes are 1.6 to 2.4 per cent and 1.7 to 2.8 per cent, respectively.

Referring to this data, the authors said, “In this study, dietary insufficient (1.10 and 1.69 per cent) or excessive (3.56 and 4.36 per cent) lysine retarded the growth rate and feed utilization, which reached the highest values in the 2.30 to 3.08 per cent lysine groups.”