Effects of Jerusalem Artichoke (Helianthus tuberosus) as a Prebiotic Supplement in the Diet of Red Tilapia (Oreochromis spp.)

SIMPLE SUMMARY: Factors such as changes in water quality, the transport and handling of the fish, the presence of pollutants, and the high densities used in intensive farming of red tilapia, among others, can cause oxidative stress in fish, which can lead to immune system suppression and increase the risk of opportunistic infections. The use of Jerusalem artichoke (JA) as an oligofructose-rich prebiotic dietary supplement in fish feed could enhance growth performance, hematological and immunological parameters, as well as disease resistance. However, the effect of JA in diets for red tilapia is poorly reported. In the present study, we evaluated the effects of a Jerusalem artichoke-supplemented diet on the blood chemistry, growth performance, intestinal morphology, expression of antioxidant-related genes, and disease resistance against Aeromonas veronii challenge in juvenile red tilapia. The results of JA-supplemented (JA5 and JA10) diets showed beneficial effects in terms of growth performance, blood chemistry, and intestinal morphology. Importantly, the prebiotic diets (JA5 and JA10) were associated with a significant increase in the expression of gpx1 and gst antioxidant-related genes and disease resistance against A. veronii. In conclusion, prebiotic diets have the potential to be employed as prospective supplements in sustainable red tilapia farming. ABSTRACT: The aim of the present study was to evaluate the effects of a Jerusalem artichoke-supplemented diet on the blood chemistry, growth performance, intestinal morphology, expression of antioxidant-related genes, and disease resistance against Aeromonas veronii challenge in juvenile red tilapia. A completely randomized design (CRD) was followed to feed red tilapias with three experimental diets: control, 5.0 g/kg JA-supplemented (JA5), or 10.0 g/kg JA-supplemented (JA10) diets in triplicates for 4 weeks. The results revealed that the growth performance, weight gain (WG), specific growth rate (SGR), and average daily gain (ADG) of fish fed diets JA5 and JA10 were significantly higher (p < 0.05) than those of fish fed the control diet. Fish fed the control diet had significantly higher T-bilirubin, D-bilirubin, and ALT in blood serum than fish fed JA5 and JA10, as well as higher BUN than fish fed JA5. The number of goblet cells in the proximal and distal parts of the intestine revealed that the number of acid, neutral, and double-staining mucous cells of fish fed diets JA5 and JA10 was significantly higher (p < 0.05) than in fish fed the control diet. The diets including the prebiotic (JA5 and JA10) were associated with a significant increase in the expression of gpx1 and gst antioxidant-related genes and disease resistance against A. veronii in juvenile red tilapia. Therefore, JA5 and JA10 can be employed as promising prebiotics for sustainable red tilapia farming.