Rearing Monosex Tilapia at Low Salinity Levels Using Locally Available Protein Sources
Nour Albahri *
Department of Fisheries Resources, High Institute of Marine Research, Latakia University (formerly Tishreen university), Lattakia, Syria.
Amir Ibrahim
Department of Fisheries Resources, High Institute of Marine Research, Latakia University (formerly Tishreen university), Lattakia, Syria.
Cathrine Mansour
Department of Zoology, Faculty of Science, Latakia University (Formerly Tishreen University), Lattakia, Syria.
*Author to whom correspondence should be addressed.
Abstract
This study focused on several essential elements of fish farming. Such as developing diets from locally available and cheap protein sources, comparing plant/animal protein sources in diets, identifying the most effective source for increasing fingerling weight and protein content, achieving the best feed conversion efficiency, and clarifying the effect of these sources on behavior and growth of monosex tilapia fingerlings, which are being cultured for the first time in Syria under low-salinity waters. This will positively affect the future of fish farming projects and their investments.
This study was designed as an experimental research conducted at the Department of Fisheries Resources, High Institute of Marine Research, and Department of Zoology, Faculty of Science, Latakia University/Lattakia /Syria, from May to August 2023.
Four diets were prepared, all with equal protein content (35%), but differing in protein source (plant/animal); M1: soybean meal, M2: cottonseed meal, M3: poultry slaughterhouse waste, and M4: a mixture of (soybean meal + cottonseed meal + poultry slaughterhouse waste). Monosex tilapia fingerlings were obtained during May 2023 from the nearby Al-Sin fishery research field station (Banyas/Syria). They were distributed in the laboratory glass tanks of Lattakia University and fed till satiation, twice a day for 63 days. Hydrological factors, individual behavior and mortality rates were monitored daily.
The results showed that fingerlings fed on M1 and M3 diets had good feed conversion rates, high daily growth rate, good protein content, and low mortality compared to the undesirable M2 diet, which resulted in lower feed consumption, slight weight gain, bad feed conversion ratio and increased mortality. Fingerlings feeding on M4 diet achieved the best results in terms of feed conversion ratio and weight gain with high protein content.
These results indicate that some local protein sources can be added to diets as a primary protein source that positively affect growth, providing economic and environmental benefits for monosex tilapia fingerlings in low salinity water. This confirms the adaptability and successful culture of monosex tilapia in low-salinity water environments.
The study recommends rearing of monosex tilapia in low-salinity waters, adopting soybean meal and poultry slaughterhouse waste as the main ingredients in monosex tilapia diets. Conversely, Cottonseed meal is not recommended as the main source of plant protein in feed without pretreatment, due to its negative effect on growth rate.
Keywords: Monosex tilapia, fish farming, low salinity, alternative protein, diet compositions