Nutritional programming improves dietary plant protein utilization in zebrafish Danio rerio

Area of Science:

• Aquaculture Nutrition
• Zebrafish Models
• Nutritional Programming

Background:

• Dietary plant protein (PP) presents utilization challenges in aquaculture.
• Nutritional Programming (NP) can mitigate negative effects of PP by early-life dietary exposure.
• Understanding the timing of NP is crucial for optimizing PP utilization.

Purpose of the Study:

• To investigate the impact of NP timing on zebrafish growth, appetite hormone expression, and gut morphology.
• To determine if early-life NP enhances the utilization of dietary plant protein (PP) in later life stages.
• To identify potential morphological adaptations in the gut responsible for improved PP utilization.

Main Methods:

• Zebrafish larvae were divided into four groups with varying dietary regimens: control (fishmeal-based), NP with PP enrichment, timed NP (T-NP) with PP, and a PP-only diet.
• Growth performance, including weight gain, was monitored during the plant protein (PP) challenge phase.
• Gene expression of appetite-stimulating hormones (ghrelin, cholecystokinin, neuropeptide Y) and intestinal villus morphology were analyzed.

Main Results:

• The timed NP (T-NP) group exhibited the highest weight gain during the PP challenge compared to control and PP-only groups.
• Ghrelin expression in the brain was elevated in T-NP, while gut ghrelin was reduced in NP groups. Cholecystokinin showed an inverse pattern.
• T-NP group displayed the largest villus length to width ratio in the middle intestine, indicating enhanced gut morphology.

Conclusions:

• Nutritional programming (NP) induced during juvenile stages significantly improves zebrafish growth.
• Early-life NP influences the regulation of digestive hormones and intestinal morphology, contributing to better plant protein (PP) utilization.
• The timing of NP is a critical factor in enhancing PP utilization and overall fish performance.