This study aimed to evaluate the liquid seaweed extract (TAM®) as a functional feed additive for Nile tilapia (Oreochromis niloticus) to assess its effects on growth performance, blood parameters, tissue histology, immune responses, and related gene expressions under several feeding regimes. Nile tilapia fingerlings (initial weight 12.64 g) were reared for 70 days with 360 fish per group (three replicates) in semi-intensive earthen pond aquaculture, using 15 net-enclosure replicates (18 m3 each) within an 8,400 m2 commercial fish pond at Shader Azzam farm. The water was exchanged at 10% daily from Al-Salam Channel irrigation water, maintaining a stocking density of 20 fish m⁻3. Four diet groups were implemented in this study. Fish were fed diets supplemented with constant TAM® supplementation (200 mL kg⁻1 diet) at feeding rates of 1%, 2%, and 3% body weight day⁻1 (TAM-D1%, TAM-D2%, and TAM-D3%, respectively). The 4th group is a control group (C-D3%), with no TAM® supplementation, with a constant feeding rate of 3% BW day⁻1. Feeding rates have been adjusted weekly based on body weight. The daily diet levels were manually offered three times a day. The TAM-D3% group showed superior feed utilization and growth performance than the other feeding groups (p < 0.05). Red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), white blood cells (WBC), total albumin (TA), and total protein (TP) increased with higher feeding rates, but the TAM-D3% group showed the highest values. The increase in immune response values and gene expressions of growth (insulin-growth factor 1, IGF-I, and growth hormone, GH) and immunity (interleukin 1 beta, IL-1β, and tumor necrosis factor alpha, TNF-α) associated genes tended to increase with the increase in feeding rates, and the highest values were recorded in the TAM-D3% group. Notably, Nile tilapia fed TAM-D2% exhibited growth performance and physiological stability comparable to the unsupplemented control group fed at C-D3%, under the same conditions. These findings suggest that TAM® supplementation may support efficient growth even at adjusted feeding rates. In the future, research should focus on identifying the specific active compounds in TAM® and optimizing its effectiveness.

Seaweed Liquid Extract Improves Growth, Immunity, and Gene Expression in Nile Tilapia (Oreochromis niloticus)

期刊论文
发表日期：

2026年6月1日

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Mohamed Ashour,
Einar Ringø,
Fawzia S. Ali,
Ahmed Mamoon,
Othman F. Abdelzaher,
Roshmon Thomas Mathew,
Abdallah Tageldein Mansour,
Yousef Ahmed Alkhamis,
Elsayed S. I. Mohammed,
Hesham S. Hassanien,
Mohamed A. Elokaby,
Mohamed M. Mabrouk

摘要

This study aimed to evaluate the liquid seaweed extract (TAM^®) as a functional feed additive for Nile tilapia (Oreochromis niloticus) to assess its effects on growth performance, blood parameters, tissue histology, immune responses, and related gene expressions under several feeding regimes. Nile tilapia fingerlings (initial weight 12.64 g) were reared for 70 days with 360 fish per group (three replicates) in semi-intensive earthen pond aquaculture, using 15 net-enclosure replicates (18 m³ each) within an 8,400 m² commercial fish pond at Shader Azzam farm. The water was exchanged at 10% daily from Al-Salam Channel irrigation water, maintaining a stocking density of 20 fish m⁻³. Four diet groups were implemented in this study. Fish were fed diets supplemented with constant TAM^® supplementation (200 mL kg⁻¹ diet) at feeding rates of 1%, 2%, and 3% body weight day⁻¹ (TAM-D_1%, TAM-D_2%, and TAM-D_3%, respectively). The 4^th group is a control group (C-D_3%), with no TAM^® supplementation, with a constant feeding rate of 3% BW day⁻¹. Feeding rates have been adjusted weekly based on body weight. The daily diet levels were manually offered three times a day. The TAM-D_3% group showed superior feed utilization and growth performance than the other feeding groups (p < 0.05)_. Red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), white blood cells (WBC), total albumin (TA), and total protein (TP) increased with higher feeding rates, but the TAM-D_3% group showed the highest values. The increase in immune response values and gene expressions of growth (insulin-growth factor 1, IGF-I, and growth hormone, GH) and immunity (interleukin 1 beta, IL-1β, and tumor necrosis factor alpha, TNF-α) associated genes tended to increase with the increase in feeding rates, and the highest values were recorded in the TAM-D_3% group. Notably, Nile tilapia fed TAM-D_2% exhibited growth performance and physiological stability comparable to the unsupplemented control group fed at C-D_3%, under the same conditions. These findings suggest that TAM_® supplementation may support efficient growth even at adjusted feeding rates. In the future, research should focus on identifying the specific active compounds in TAM^® and optimizing its effectiveness.