Effect of dietary phosphorus level on defense system parameters and liver HSP70 concentration in juvenile Japanese flounder, Paralichthys olivaceus
Year: 2022
Type: article
Abstract: A feeding trail was performed to investigate the effect of dietary phosphorus (P) level on defense system in juvenile Japanese flounder. Calcium mono phosphate was used as dietary inorganic-P source. Three semi-purified diets with 3 levels of P (6, 10 and 18 g/kg diet, respectively) were prepared and fed to juveniles (average initial body weight, means ± S.E., 7.3 ± 0.3 g) for 30 days. After termination of the feeding trail, growth parameters were calculated, and mucus lysozyme activity, mucus bactericidal activity and the levels of heat shock protein 70 family (HSP70s) in liver were measured. Results indicated that final weight, weight gain and feed efficiency significantly improved with increasing dietary P level, and the highest growth parameters were obtained from the fish fed diet containing 18 g/kg P. Mucus lysozyme activity and mucus bactericidal activity were significantly improved with the increasing dietary P level. The highest level of HSP70s in liver (35.97 ng/mg protein) was observed on fish fed the diet containing 18g/kg P, and it was 2 and 2.6 folds higher (P<0.05) than those fish fed the diet with 10 and 6 g/kg P, respectively. In conclusion, P deficiency has significant effect on growth and measured defense system parameters, therefore, the dietary inclusion of P might affect the defense system and stress tolerance of juvenile Japanese flounder. Highest level of mucus lysozyme activity, HSP70s in liver, and bactericidal activities with reduced survival rate of E. coli was observed in fish fed diets incorporated with 1.8% P, that also maintained best growth performance in Japanese flounder.
Source: MARINE REPORTS (MAREP)
Institution: Kagoshima University
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W4310661007