The Immunostimulatory Effects of Commercial Feed Additives on Growth Performance, Non-specific Immune Response, Antioxidants Assay, and Intestinal Morphometry of Nile tilapia, Oreochromis niloticus

Mohamed Ibrahim Kord; Tarek Mohamed Srour; Eglal Ali Omar; Ahmed Awny Farag; Abdel Aziz Moussa Nour; Hala Saber Khalil

doi:10.3389/fphys.2021.627499

The Immunostimulatory Effects of Commercial Feed Additives on Growth Performance, Non-specific Immune Response, Antioxidants Assay, and Intestinal Morphometry of Nile tilapia, Oreochromis niloticus

Front Physiol. 2021 Feb 25:12:627499. doi: 10.3389/fphys.2021.627499. eCollection 2021.

Authors

Mohamed Ibrahim Kord^{1

2}, Tarek Mohamed Srour², Eglal Ali Omar², Ahmed Awny Farag¹, Abdel Aziz Moussa Nour², Hala Saber Khalil^{3

4}

Affiliations

¹ Central Laboratory for Agricultural Climate, ARC, Giza, Egypt.
² Department of Animal and Fish Production, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt.
³ WorldFish, Africa Aquaculture Research and Training Center, Abbassa, Egypt.
⁴ National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt.

Abstract

The main objective of the present research was to investigate the impacts of commercial immunostimulants on growth, non-specific immune response, antioxidant enzymes, and intestinal morphometry of Nile tilapia, Oreochromis niloticus. Fish (100 ± 6.5 g) were randomly divided into five groups in triplicates (150 fish in each replicate), stocked in 20 m² of aerated concrete ponds. The fish were fed on a control diet (30.0% crude protein) (control), and four experimental diets supplemented with Yeast Plus^®, Digestarom^®, and Biotronic^® Top³ at 1 kg ton^-1, and Sanolife PRO-F^® at 0.5 kg ton^-1. After the experimental period, the highest significant yield (kg m^-3), mean final weight (g fish^-1), average weight gain (g fish^-1), and specific growth rate (% body weight day^-1), were recorded in fish fed on the diet supplemented by Sanolife PRO-F, followed by Yeast Plus ponds. The lowest yield was recorded in the control group. However, the feed conversion ratio was significantly decreased with Sanolife PRO-F diet. Furthermore, the hematological analysis increased in the following ascending order: Sanolife PRO-F^®; Yeast Plus^®; Biotronic^® Top3 and finally Digestarom^® groups. The lowest concentrations of white blood cells, red blood cells, hematocrite, and hemoglobin (P ≤ 0.05) were observed in the control group. The levels of phagocytic activity and phagocytic index were significantly higher in fish fed with Sanolife PRO-F^® group (P ≤ 0.05). Likewise, serum lysozyme activity was significantly highest in Sanolife PRO-F (0.63 and 0.68 U/mL, after 0.5 min and 3 min, respectively). Levels of total serum proteins, globulin, Immunoglobulin M, catalase, and super oxide dismutase were significantly higher in fish fed with Sanolife PRO-F^® supplement. On the contrary, length measurement of the intestinal villus height/width, absorption area, crypt depth, and goblet cells, were significantly lower in the control group, whereas their highest values was observed in fish fed Sanolife PRO-F (P ≤ 0.05). Consequently, Sanolife PRO-F^® is recommended at a level of 0.5 kg ton^-1, to improve the growth performance, antioxidative capacity, and immune response of Nile tilapia.

Keywords: antioxidant enzyme; immunostimulants; intestinal morphology; lysozyme; phagocytic index.