title: Morphometric characterization of the first blastomeres of rainbow trout (Oncorhynchus mykiss).
abstract: In the following investigation the morphometric characteristics of the first two blastomeres of rainbow trout (Oncorhynchus mykiss) were determined. Embryos were incubated at 9°C and then fixed in a Stockard solution every 30 min starting from 8.5 to 12.5 h of incubation post fertilization. Embryonic discs were extracted and microphotographs were taken with Q Capture Pro 5.0 software using a stereomicroscope Olympus SZX7. The average size of the blastodiscs was 941.22 ± 160.42 μm. The first cleavage finished after approximately 12 h of incubation. The first two blastomeres were regularly symmetrical in their morphology. Blastomere 1 had an average length (L) of 942.68 ± 105.56 μm and width (W) of 467.34 ± 64.33 μm. Blastomere 2 had an average length of 887.60 ± 101.65 and width of 454.49 ± 47.25 μm (n = 91). Significant differences were found between the length and width of blastomeres 1 and 2. The proportion between the length of blastomeres 1 and 2 was 0.94 ± 0.07 (n = 91); between the width of blastomeres 1 and 2 it was 0.88 ± 0.11 (n = 91); and the width/length ratio was 0.51 ± 0.09 (n = 182). It was concluded that rainbow trout blastomeres tend to be asymmetrical in length with a higher dispersion of widths.
authors.affiliation: Universidad Católica de Temuco, Facultad de Recursos Naturales, Escuela de Acuicultura, Temuco, Chile. ivisler@uct.cl
authors.forename: Iván I
authors.initials: II
authors.lastname: Valdebenito
authors.forename: Rubén R
authors.initials: RR
authors.lastname: Sánchez
authors.forename: Brian R
authors.initials: BR
authors.lastname: Effer
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Ubilla
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian / Q000378:metabolism* / Q000648:ultrastructure; D017686:Oncorhynchus mykiss / Q000196:embryology*