title: Effect of guava leaves on the growth performance and cytokine gene expression of Labeo rohita and its susceptibility to Aeromonas hydrophila infection.
abstract: The present study aimed to evaluate the effects of Psidium guajava L. (guava) leaves on the growth and immune response of the fish species Labeo rohita and its susceptibility to Aeromonas hydrophila infection. Diets containing five different concentrations of guava leaves (0% [basal diet], 0.1% [G1], 0.5% [G2], 1% [G3], and 1.5% [G4]) were fed to fish (average weight: 11.1 g) for 60 days. Various growth and immune parameters were examined 60 days post-feeding. Fish were challenged with A. hydrophila at the end of the trial, and mortalities were recorded over 15 days post-infection. We found that growth parameters such as percent weight gain (657.61 ± 9.74) and specific growth rate (3.37 ± 0.021) were significantly higher in G2 group than in the control (P < 0.05). Among the immune parameters examined, lysozyme levels (79.5 ± 5.1 U mL(-1)), leukocyte phagocytic activity (52 ± 4.3%), and alternative complement pathway activity (ACP) (186.1 ± 8.3 U mL(-1)) were significantly high (P < 0.05) in G2 fed group; there was, however, no significant effect of guava leaves at any concentration on plasma IgM level. Of the cytokine-related genes examined, interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) were up-regulated in the head-kidney, intestine, and hepatopancreas of fish fed experimental diets, and expression was significantly higher in G2 and G3 than in the control group. In contrast, gene expression of IL-10, transforming growth factor-beta (TGF-β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and transcription factor nuclear factor-κB (NF-κB) were down-regulated in the treatment groups. Moreover, fish fed the G2 diet exhibited a significantly higher post-challenge survival rate (66.66%). Collectively, these results suggest that dietary supplementation with guava leaves (at 0.5% concentration) could promote growth performance and strengthen immunity of L. rohita. Guava leaves therefore represent a promising feed additive for carps in aquaculture.
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Giri
authors.affiliation: School of Life Sciences, Jawharlal Nehru University, New Delhi 110067, India.
authors.forename: Shib Sankar
authors.initials: SS
authors.lastname: Sen
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chi
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Hyoun Joong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Saekil
authors.initials: S
authors.lastname: Yun
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea. Electronic address: parksec@snu.ac.kr.
authors.forename: Se Chang
authors.initials: SC
authors.lastname: Park
authors.affiliation: Dept. of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Sukumaran
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D016980:Aeromonas hydrophila / Q000502:physiology; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D017756:Aquaculture; D003530:Cyprinidae / Q000235:genetics / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis*; D004198:Disease Susceptibility / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D005786:Gene Expression Regulation / Q000187:drug effects; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D031647:Psidium / Q000737:chemistry*
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D010936:Plant Extracts
keywords: Aeromonas hydrophila; Cytokine-related genes; Growth performance; Labeo rohita; Psidium guajava