Desenvolvimento de protocolo para indução de triploidia em tambaqui (Colossoma macropomum) e avaliação dos efeitos sobre a puberdade, bem-estar e recria

Abstract

Tambaqui (Colossoma macropomum) is the most important native species in Amazonian and Brazilian aquaculture, standing out for its high economic value and potential for insertion into international markets. However, its production still relies predominantly on conventional practices, with a reduction in the availability of pure stocks and a lack of species-specific technologies, highlighting the need for innovative and sustainable strategies. In this context, triploidy induction emerges as a promising alternative for reproductive control, environmental biosafety, and production intensification. The present study aimed to establish an efficient protocol for triploidy induction in C. macropomum using hydrostatic pressure shock and to evaluate its effects on early growth, gonadal maturation, welfare, and physiological condition. Two experimental trials were conducted using a hydrostatic pressure shock of 8000 psi. In the first trial, newly fertilized eggs were subjected to pressure shock at different post-fertilization times to identify the most efficient window for triploidy induction. In the second trial, different shock durations were tested at the previously selected times. All treatments resulted in high triploidization rates (>93%), with higher embryonic survival and final gastrula survival observed when shocks were applied between 65 and 95 seconds post-fertilization. Monthly growth assessments performed during the first six months of life indicated superior performance of triploid fish compared to diploids in terms of body weight, body height, and total and standard lengths. Histological analyses of gonads at 20 months of age demonstrated infertility in triploid fish, whereas diploid individuals exhibited advanced gonadal development. Physiological condition and health status were assessed through hematological and biochemical parameters, showing that triploids presented larger erythrocytes, lower erythrocyte counts, and higher mean corpuscular volume and mean corpuscular hemoglobin values, without impairment of mean corpuscular hemoglobin concentration or plasma biochemical homeostasis. These results indicate the occurrence of compensatory physiological adjustments associated with increased genomic content, ensuring efficient oxygen transport and maintenance of metabolic functions. In conclusion, triploidy represents a viable and sustainable tool for tambaqui aquaculture, contributing to the strengthening of native fish farming in Brazil.