title: Δ6-fatty acid desaturase and fatty acid elongase mRNA expression, phagocytic activity and weight-to-length relationships in channel catfish (Ictalurus punctatus) fed alternative diets with soy oil and a probiotic.
abstract: A time-course feeding trial was conducted for 120 days on juvenile channel catfish (Ictalurus punctatus) to study the effects of diets differing in oil source (fish oil or soy oil) and supplementation with a commercial probiotic. Relative levels of Δ6-fatty acid desaturase (Δ6-FAD) and fatty acid elongase (FAE) expression were assessed in brain and liver tissues. Both genes showed similar expression levels in all groups studied. Fish weight-to-length relationships were evaluated using polynomial regression analyses, which identified a burst in weight and length in the channel catfish on day 105 of treatment; this increase was related to an increase in gene expression. Mid-intestinal lactic acid bacterium (LAB) count was determined according to morphological and biochemical criteria using API strips. There was no indication that intestinal LAB count was affected by the modified diets. The Cunningham glass adherence method was applied to evaluate phagocytic cell activity in peripheral blood. Reactive oxygen species (ROS) generation was assessed through the respiratory burst activity of spleen macrophages by the NBT reduction test. Probiotic-supplemented diets provided a good substrate for innate immune system function; the phagocytic index was significantly enhanced in fish fed soy oil and the probiotic, and at the end of the experimental period, ROS production increased in fish fed soy oil. The substitution of fish oil by soy oil is recommended for food formulation and will contribute to promoting sustainable aquaculture. Probiotics are also recommended for channel catfish farming as they may act as immunonutrients.
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: A
authors.initials: A
authors.lastname: Santerre
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México ceciliat@prodigy.net.mx.
authors.forename: M C
authors.initials: MC
authors.lastname: Téllez-Bañuelos
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: J
authors.initials: J
authors.lastname: Casas-Solís
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: P
authors.initials: P
authors.lastname: Castro-Félix
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: M R
authors.initials: MR
authors.lastname: Huízar-López
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: G P
authors.initials: GP
authors.lastname: Zaitseva
authors.affiliation: Departamento de Ecología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: J L
authors.initials: JL
authors.lastname: Horta-Fernández
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: E A
authors.initials: EA
authors.lastname: Trujillo-García
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: D
authors.initials: D
authors.lastname: de la Mora-Sherer
authors.affiliation: Departamento de Biología Celular y Molecular, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: J A
authors.initials: JA
authors.lastname: Palafox-Luna
authors.affiliation: Departamento de Ecología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México.
authors.forename: E
authors.initials: E
authors.lastname: Juárez-Carrillo
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D017756:Aquaculture; D001835:Body Weight; D001921:Brain / Q000201:enzymology; D004032:Diet; D000081031:Fatty Acid Elongases; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D000069196:Gastrointestinal Microbiome; D015870:Gene Expression; D007059:Ictaluridae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D050602:Linoleoyl-CoA Desaturase / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008264:Macrophages / Q000502:physiology; D010587:Phagocytosis; D019936:Probiotics / Q000008:administration & dosage; D016897:Respiratory Burst; D013024:Soybean Oil / Q000008:administration & dosage
chemical_list: D029941:Fish Proteins; D013024:Soybean Oil; D050602:Linoleoyl-CoA Desaturase; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases