Effect of Different Protein-To-Energy Levels On Growth Performance, Blood Parameters and Liver Enzymes of Grass Carp (Ctenopharyngodon idella)

Khezri, Mostafa; Javaheri Baboli, Mehran; Chelemal Dezfulnezhad, Mojdeh; Askary Sary, Aboalfazl; Ghotbeddin, Negar

Volume 18, Issue 2 (Summer 2026) 3 2026, 18(2): 30-44 | Back to browse issues page

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Khezri M, Javaheri Baboli M, Chelemal Dezfulnezhad M, Askary Sary A, Ghotbeddin N. Effect of Different Protein-To-Energy Levels On Growth Performance, Blood Parameters and Liver Enzymes of Grass Carp (Ctenopharyngodon idella). 3 2026; 18 (2) :30-44
URL: http://jmb.ahvaz.iau.ir/article-1-1117-en.html

Effect of Different Protein-To-Energy Levels On Growth Performance, Blood Parameters and Liver Enzymes of Grass Carp (Ctenopharyngodon idella)

Mostafa Khezri

, Mehran Javaheri Baboli

, Mojdeh Chelemal Dezfulnezhad

, Aboalfazl Askary Sary

, Negar Ghotbeddin

Abstract: (11 Views)

This study aimed to investigate the effect of different levels of dietary protein to energy, along with different stocking densities, on growth performance, feed efficiency, apparent digestibility, blood biochemical indices, and liver enzyme activities of grass carp (Ctenopharyngodon idella). Fish with an average initial weight of 8.4 g were fed six experimental diets for 70 days, including three levels of crude protein of 30, 35, and 40% and two levels of digestible energy of 2700 and 3400 kcal/kg, and were stocked at three densities of 10, 20, and 40 fish per tank. At the end of the experimental period, growth and feed efficiency indices including weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), and survival rate (SR) were calculated. Also, apparent digestibility, protein and energy reserves, blood biochemical indices including total protein, glucose, urea, total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and liver enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were measured. The results showed that the diet composition containing 35% protein and 3400 kcal energy at a density of 20 fish per tank, compared to other treatments, improved growth performance, increased feed efficiency, reduced FCR by 1.19 and increased apparent digestibility, protein and energy reserves. In contrast, increasing the dietary protein level to 40%, especially at a density of 40 fish per tank, did not improve growth performance and was associated with a decrease in feed utilization efficiency (P< 0.05). Blood biochemical indices and liver enzyme activities were also affected by diet composition and stocking density, indicating changes in the metabolic and physiological status of fish in response to different nutritional and rearing conditions. Overall, the results of this study indicate that a diet containing 35% protein and 3400 kcal of energy, at an average stocking density of 20 fish per tank, can be a suitable option for improving growth performance and physiological status of grass carp. However, a detailed evaluation of the economic aspect of using different levels of dietary protein requires an analysis of feed cost and production efficiency in complementary studies

Keywords: Feed use efficiency, Growth performance, Ctenopharyngodon idella, Protein to energy ratio.

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Type of Study: Research | Subject: Fisheries
Received: 2026/06/26 | Accepted: 2026/08/16 | Published: 2026/08/16