# Effects of Dietary Melissa officinalis and Feeding Strategy on Growth and Physiological Responses in Hybrid Red Tilapia

## TL;DR

This study finds that feeding hybrid red tilapia with lemon balm leaves on alternate days improves growth and health while reducing feed costs.

## Contribution

The study introduces a novel combination of alternate-day feeding and lemon balm supplementation to enhance tilapia growth and physiological responses.

## Key findings

- Alternate-day feeding improved feed conversion ratio (FCR) to 1.68 without affecting growth.
- LBL1 supplementation increased final body weight, weight gain, and growth rate significantly.
- LBL2 supplementation improved blood parameters like hemoglobin and white blood cell count.

## Abstract

Generally, the inadequate feeding of aquatic organisms can mitigate stress and disease vulnerability. In contrast, overfeeding has worsened the water quality in addition to the high feeding cost. Hence, the present study was performed to evaluate two feeding regimes (alternate-day feeding [ADF] and daily feeding [DF]), plus dietary supplementation with Melissa officinalis (lemon balm leaves [LBL]) on growth, body composition, digestion, and hemato-physiological status of hybrid red tilapia (Oreochromis spp.). Fish (n = 180) with an average weight of 18.14 ± 0.48 g were distributed into six groups (30 fish/group; 3 replicates/group; 10 fish/replicate) in a 2 × 3 factorial feeding trial for 60 days. The groups were ADF + LBL0, ADF + LBL1, ADF + LBL2, DF + LBL0, DF + LBL1, and DF + LBL2. The LBL was added to the basal diet at the doses of 0%, 1%, and 2% (LBL0, LBL1, and LBL2), respectively. The outcomes revealed that ADF achieved the best feed conversion ratio (FCR) (1.68), but the growth did not show substantial variation between ADF and DF. The LBL1 supplementation enhanced final body weight (FBW) (33.16 g), total weight gain (TWG) (14.20 g/fish), and specific growth rate (SGR) (0.93 %/day). The interaction between LBL and feeding strategies showed that the ADF + LBL1 had the best FCR (1.31). Crude lipid and ash content substantially changed (p < 0.05) by feeding regimes and LBL addition. The DF + LBL0 group had the highest lipid (32.08%) and the lowest ash content (18.28%). Dietary LBL2 significantly increased (p < 0.05) hemoglobin (Hb) (8.30 g/dL), hematocrit (Hct) (26.25%), and white blood cell (WBC) count (419.44 × 103/mm3). Moreover, the ADF regime significantly decreased (p < 0.05) glucose level (47.83 ng/L); meanwhile, the DF regime notably increased amylase activity (47.66 U/g protein). Our conclusion suggested that feeding hybrid red tilapia with an ADF schedule with a diet enriched with LBL can improve growth, feed utilization, and physiological response. This offers an avenue to assist the aquaculture sector and lower feed expenses.