Growth performance, survival, body composition, hematological parameters, intestinal histomorphology, and digestive enzymes’ activity in juvenile rainbow trout (Oncorhynchus mykiss) fed dietary Immunogen®

ABSTRACT

The aim of present study was to evaluate the effects of dietary Immunogen® supplementation on juvenile rainbow trout, where 120 fish (81.7 ± 2.23 g) were fed diets supplemented with either 0.0 (control) or 2 g Immunogen® kg⁻¹ for 7 weeks. The fish fed the Immunogen®-supplemented diet showed an improvement in growth performance, feed utilization, and protein efficiency ratio and a decrease in feed conversion ratio. The fish fed the Immunogen®-supplemented diet showed higher body protein content. There were no significant differences in red blood cell count, eosinophil, or lymphocyte between the treatments. However, white blood cells, neutrophil, and monocyte were higher in the fish fed fish with the Immunogen®-supplemented diet. Supplementation of Immunogen® has increased villi height and tunica muscularis thickness as well as gut protease and lipase activities. The present study revealed that supplementation of Immunogen® can improve intestinal morphology and increase digestive enzyme activity and consequently increase trout growth and feed efficiency.

KEYWORDS:

• Prebiotic
• growth performance
• intestinal morphology
• blood parameters

Acknowledgment

The authors would like to thank the staff at the Department of Fisheries, University of Tehran, for providing facilities and cooperation in this research project.

Conflicts of interest

The authors report no conflict of interest for the publication of the present work.