title: The effect of environmental colour on the growth, metabolism, physiology and skin pigmentation of the carnivorous freshwater catfish Lophiosilurus alexandri.
abstract: The growth, physiology and skin pigmentation of pacamã Lophiosilurus alexandri juveniles were evaluated in an experiment using different tank colours (white, yellow, green, blue, brown and black) over an 80 day period. The tank colours did not cause significant differences to final body mass, total length, survival rate, carcass composition (moisture, crude protein, ash, ether extract, calcium, phosphorus, energy), or to plasma protein, triglyceride and cholesterol values. Haematocrit values, however, were highest for fish kept in white tanks (ANOVA P < 0·05), while the greatest haemoglobin levels were recorded for fish kept in blue and brown tanks (P < 0·01). The concentrations of cortisol (P < 0·001) and glucose (P < 0·01) were the most in fish in the black tanks. Tank colour affected skin pigmentation significantly, with fish in white tanks having the highest values of L* (brightness) and the lowest values in blue and black tanks. L*, however, decreased in all treatments throughout the experiment. C*abincreased significantly over the course of the experiment in fish kept in white tanks. Similar increases of C*abwere recorded in the other treatments but to a lesser extent. The use of black tanks during the cultivation of L. alexandri caused stress and should be avoided. Cultivation in white and yellow tanks produced individuals with a pale skin colour, while cultivation in blue and black tanks resulted in juveniles with a darker and more pigmented skin.
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: D C
authors.initials: DC
authors.lastname: Costa
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: C C
authors.initials: CC
authors.lastname: Mattioli
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: W S
authors.initials: WS
authors.lastname: Silva
authors.affiliation: Fundação Instituto de Pesca do Estado do Rio de Janeiro, Unidade de Pesquisa e Reprodução de Peixes, Av. Presidente Vargas, 197, Parque de Exposições, CEP 28540-000, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Takata
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: F O P
authors.initials: FO
authors.lastname: Leme
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: A L
authors.initials: AL
authors.lastname: Oliveira
authors.affiliation: Universidade Federal de Minas Gerais, Escola de Veterinária, Avenida Antônio Carlos, n° 6627, CEP 30161-970, Brazil.
authors.forename: R K
authors.initials: RK
authors.lastname: Luz
mesh_terms: D000818:Animals; D002397:Catfishes / Q000254:growth & development*; D004777:Environment; D005618:Fresh Water; D006854:Hydrocortisone / Q000097:blood; D012880:Skin Pigmentation / Q000502:physiology*
chemical_list: D006854:Hydrocortisone
keywords: behaviour; cortisol; skin pigmentation; tank colour