Avaliação do uso de diferentes fontes de carbono fermentadas com probiótico no cultivo do camarão marinho Penaeus vannamei infectado com o vírus da mionecrose infecciosa (IMNV)

Abstract

Several pathogenic agents hinder the development of shrimp farming, with viruses and bacteria being the most prominent. The objective of this study was to evaluate the effects of fermented products on zootechnical performance (survival, weight gain, and FCR) of shrimp; to assess the effects of fermented products with probiotics on the physical-chemical parameters of the culture water; and to analyze the growth of bacteria from the genera Bacillus, Lactobacillus, Vibrio, and yeasts. The study involved the evaluation of four probiotic fermented mixtures: BM (probiotics), FA (rice bran and probiotics), FM (sugarcane molasses and probiotics), and FMA (rice bran, sugarcane molasses, and probiotics), in addition to a control, CTL (sugarcane molasses). The mixtures were applied daily to the shrimp culture water over a continuous period of 65 days. Shrimp were stocked at a density of 117 animals/m² in 40 circular tanks with a volume of 1 m³. At harvest, final survival (%), growth (g/week), biomass gain (g), productivity gain (g/m²), and feed conversion ratio (FCR) were determined. Shrimp reached a final survival of 46.1 ± 8.8; 62.8 ± 16.4; 65.7 ± 19.7; 88.3 ± 8.0, and 49.8 ± 8.8 g/m² for the CTL, BM, FA, FM, and FMA treatments, respectively. Productivity was 515 g/m² for the FM treatment and 291, 382, 356, and 356 g/m² for the CTL, BM, FA, and FMA treatments, respectively. Vibrio spp. counts were quantified, with results of 3.21x10³±1.23x10³; 5.52x10³±1.10x10³; 3.24x10³±1.99x10³; 2.46x10³±1.15x10³, and 2.60x10³±1.27x10³ for the CTL, BM, FA, FM, and FMA treatments, respectively. The viral load of IMNV was also quantified, yielding results of 15,480.67 ± 508.13; 19,838 ± 214.11; 16,614 ± 747.81; 9,240 ± 699, and 10,996.67 ± 924.18 viral copies/μg of RNA for the CTL, BM, FA, FM, and FMA treatments, respectively. The FM treatment showed the lowest loads of Vibrio spp. and IMNV, which may have promoted the highest survival rates. Thus, it can be concluded that the fermented molasses and probiotics (FM) yield satisfactory results for the survival and productivity of P. vannamei culture, even under co-infection with Vibrio spp. and IMNV.