Dietary Valine Requirement of Juvenile Olive Flounder ( Paralichthys olivaceus )

• Published in: Aquaculture nutrition Vol. 2024; no. 1
• Main Authors: Shin, Jaehyeong, Ko, Deahyun, Hasanthi, Mirasha, Eom, Gunho, Lee, Kyeong–Jun
• Format: Journal Article
• Language: English
• Published: Oxford Hindawi Limited 01.01.2024; Wiley
• Subjects: Amino acids; Body weight; Condition factor; Cytokines; Diet; Dry matter; Efficiency; Feed conversion; Feeding experiments; Fish; Flounder; Immune system; Lipids; Marine fishes; Nitrogen; Paralichthys olivaceus; Proteins; Regression analysis; Salinity; Tanks; Valine; Water temperature; South Korea; Chile; United States > US; China
• ISSN: 1353-5773; 1365-2095
• DOI: 10.1155/2024/3643845

This study was conducted to estimate dietary valine (Val) requirement for juvenile olive flounder ( Paralichthys olivaceus ). In a feeding trial, a total of 540 fish (initial body weight: 23.0 ± 0.2 g) were stocked into 18 tanks (210 L). Six experimental diets containing graded levels of Val (4, 8, 12, 16, 20, and 24 g/kg, dry matter basis) were fed to the fish in triplicate groups for 13 weeks. The lowest growth, feed utilization, and survival were observed in 4 g/kg Val group ( P < 0.05). Dietary Val deficiency resulted in significant decreases ( P < 0.05) in whole‐body protein and Val concentrations, hepatosomatic index, condition factor and plasma protein and cholesterol levels. Nonspecific immunity and antioxidant activities were significantly lower ( P < 0.05) in 4 g/kg Val group than in other groups. Dietary Val deficiency upregulated the expression of proinflammatory cytokines and downregulated the expression of anti‐inflammatory cytokines and intestinal tight junction protein ( occludin ) ( P < 0.05). Mucosal fold height and submucosa and muscularis thickness of fish intestine were significantly lower ( P < 0.05) in fish fed 4 g/kg Val diet. Relatively lower lipid droplet in hepatic cell was observed in 4 g/kg Val group. Our findings suggested that dietary Val requirements for juvenile olive flounder would be 17.7–18.9 g Val/kg (35.4–37.8 g/kg on the basis of crude protein), estimated by quadratic regression analysis based on the weight gain, protein efficiency ratio, and protein retention efficiency.