Effect of dietary phenylalanine on growth performance and intestinal health of triploid rainbow trout (Oncorhynchus mykiss) in low fishmeal diets

Shuze Zhang; Chang'an Wang; Siyuan Liu; Yaling Wang; Shaoxia Lu; Shicheng Han; Haibo Jiang; Hongbai Liu; Yuhong Yang

doi:10.3389/fnut.2023.1008822

Effect of dietary phenylalanine on growth performance and intestinal health of triploid rainbow trout (Oncorhynchus mykiss) in low fishmeal diets

Front Nutr. 2023 Mar 7:10:1008822. doi: 10.3389/fnut.2023.1008822. eCollection 2023.

Authors

Shuze Zhang^{1

2}, Chang'an Wang^{1

2}, Siyuan Liu^{1

3}, Yaling Wang^{1

4}, Shaoxia Lu¹, Shicheng Han¹, Haibo Jiang⁵, Hongbai Liu¹, Yuhong Yang²

Affiliations

¹ Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, China.
² College of Animal Science, Northeast Agricultural University, Harbin, China.
³ College of Life Science, Dalian Ocean University, Dalian, China.
⁴ College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
⁵ College of Animal Science, Guizhou University, Guiyang, China.

Abstract

This study aimed to investigate the effects of phenylalanine on the growth, digestive capacity, antioxidant capability, and intestinal health of triploid rainbow trout (Oncorhynchus mykiss) fed a low fish meal diet (15%). Five isonitrogenous and isoenergetic diets with different dietary phenylalanine levels (1.82, 2.03, 2.29, 2.64, and 3.01%) were fed to triplicate groups of 20 fish (initial mean body weight of 36.76 ± 3.13 g). The weight gain rate and specific growth rate were significantly lower (p < 0.05) in the 3.01% group. The trypsin activity in the 2.03% group was significantly higher than that in the control group (p < 0.05). Amylase activity peaked in the 2.64% treatment group. Serum superoxide dismutase, catalase, and lysozyme had the highest values in the 2.03% treatment group. Liver superoxide dismutase and catalase reached their maximum values in the 2.03% treatment group, and lysozyme had the highest value in the 2.29% treatment group. Malondialdehyde levels in both the liver and serum were at their lowest in the 2.29% treatment group. Interleukin factors IL-1β and IL-6 both reached a minimum in the 2.03% group and were significantly lower than in the control group, while IL-10 reached a maximum in the 2.03% group (p < 0.05). The tight junction protein-related genes occludin, claudin-1, and ZO-1 all attained their highest levels in the 2.03% treatment group and were significantly higher compared to the control group (p < 0.05). The intestinal villi length and muscle layer thickness were also improved in the 2.03% group (p < 0.05). In conclusion, dietary phenylalanine effectively improved the growth, digestion, absorption capacity, antioxidant capacity, and intestinal health of O. mykiss. Using a quadratic curve model analysis based on WGR, the dietary phenylalanine requirement of triploid O. mykiss fed a low fish meal diet (15%) was 2.13%.

Keywords: intestinal health; low fish meal diet; phenylalanine; requirement; triploid Oncorhynchus mykiss.

Grants and funding

This study was supported by the Central Public-Interest Scientific Institution Basal Research Fund, HRFRI (HSY202202M), the China Agriculture Research System of MOF and MARA (CARS-46), National Postdoctoral Fund (2022MD713817), the China Scholarship Council (202003260012), and the Key Scientific Research Project of Heilongjiang Province (JD22A017).