Desempenho zootécnico e desenvolvimento gonadal de machos e fêmeas de matrinxã (Brycon amazonicus)

Abstract

The matrinxã Brycon amazonicus is a commercially valuable Amazonian species, the second most produced in the North region due to its rapid weight gain, omnivorous diet, and good acceptance in the local market. The growing demand for its meat has driven the expansion of fish farming for this species, although specific studies to support the development of technologies aimed at increasing productivity are still lacking. In this context, the sexual categories of B. amazonicus (females, primary males, and secondary males) were analyzed to compare their productive performance and morphologically characterize gonadal development under semi-intensive farming during a fattening cycle. Samples were collected monthly between 5 and 12 months of age (n = 16), with a final sample taken at 17 months during harvest (n = 40). Biometric, histological, and hormonal analyses were conducted, including 17β-estradiol and testosterone levels. The results revealed that the sex ratio between functional females and males (males + secondary males) was 1:1 by the chi-square test. Among the biometric variables analyzed, only body height showed a significant difference, being greater in females. Regarding gonadal maturation up to 17 months of age, females were in the primary development phase, while primary and secondary males were in the regeneration and regression phases, respectively. These results indicate that mixed culture remains the most viable option, since B. amazonicus did not show significant differences in length and weight between the different sex categories.