Evaluating Distiller's Dried Grains with Solubles as a Partial Substitute for Soybean Meal in the Nile Tilapia (Oreochromis niloticus) Diets: Growth Performance, Physiological Induces, and Intestinal Histomorphometry

Matter, Ali; Hussein, Mohsen Saleh; Gewida, Ahmed G. A.; Wafa, Mahmoud Elsadek; Goda, Ashraf Abd EL Samea

doi:10.21608/ejabf.2025.441666.6983

Evaluating Distiller's Dried Grains with Solubles as a Partial Substitute for Soybean Meal in the Nile Tilapia (Oreochromis niloticus) Diets: Growth Performance, Physiological Induces, and Intestinal Histomorphometry

Document Type : Original Article

Authors

¹ El-Azhar university, Faculty of Agriculture, Fish Production Department

² Fish Production Department, Faculty of Agriculture, Al-Azhar University, Cairo, 11884, Egypt.

³ Department of Fish production, Faculty of Agriculture in Cairo, Al-Azhar University, Egypt.

⁴ Fish Production, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt

⁵ National Institute of Oceanography and Fisheries

10.21608/ejabf.2025.441666.6983

Abstract

Feed costs constitute over 60% of aquaculture production expenses, driving the need for economical protein alternatives. This study evaluated the partial replacement of dietary soybean meal with distiller's dried grains with solubles (DDGS) on growth performance, physiological parameters, and intestinal histomorphometry of the Nile tilapia (Oreochromis niloticus). Over 90 days fish (3.56±0.5 g) were fed one of five isonitrogenous (25.7% CP) and isolipidic (7.9%) diets: a soybean-based control or diets replacing 10, 20, 30, and 40% of its protein with DDGS. The 10% DDGS replacement diet yielded optimal final body weight (19.87±0.31 g), specific growth rate (1.92±0.02% day⁻¹), feed conversion ratio (1.05±0.02) and protein efficiency ratio (3.70±0.06) compared to all other treatments (P<0.05). This group also demonstrated enhanced health, indicated by significantly improved immune markers (elevated white blood cells and globulins) and superior intestinal morphology (longer villi, higher goblet cell density), which facilitated superior nutrient absorption. While higher DDGS inclusions (20-40%) maintained growth comparable to the control, the 30% level emerged as the most economically efficient, reducing feed cost per kg of fish gain by 6.36%. In conclusion, a 10% DDGS replacement is recommended to maximize tilapia health and growth, whereas a 30% replacement offers the best economic return, providing flexible strategies for sustainable and cost-effective aquaculture.

Keywords