Este estudo buscou relacionar e identificar a influência dos fenômenos ENOS nos índices de precipitação da série histórica (1910 a 2014) da estação pluviométrica de Boa Vista, Capital do Estado de Roraima, Brasil. Os procedimentos metodológicos compreenderam: a) análises estatísticas dos dados diários, mensais e anuais para definição da série pluviométrica identificação de diferentes ciclos pluviométricos; b) identificação e confrontação dos dados pluviométricos com os períodos de vigência dos fenômenos ENOS (El Niño e La Niña) a fim de identificar relações destes com anomalias observadas na série histórica. A análise da série histórica permitiu a identificação de quatro ciclos pluviométricos, representados por dois ciclos secos e outros dois úmidos. Os eventos ENOS (El Niño e La Niña) apresentaram grande compatibilidade com as variações pluviométricas da série. Os resultados apontam para a necessidade do estado e da sociedade civil se organizar aos efeitos dos ciclos de El Niño, em especial a retração do volume superficial de água disponível, estações secas mais fortes e ampliação de eventos de queimadas e, no caso dos ciclos de La Niña, recorrência de cheias e eventos associados.

The present study investigated how dietary inclusion of solubilized mannan oligosaccharide (MOS) influences growth performance, digestive health, stress resilience, and production profitability in Pacific white shrimp (Penaeus vannamei) reared under intensive synbiotic conditions. Juveniles averaging 3.00 ± 0.04 g were stocked at 100 shrimp m⁻² and fed experimental diets containing 0 (control), 1.0, 2.0, or 4.0 g kg⁻¹ MOS for 60 days. Shrimp receiving 1.0 g kg⁻¹ MOS showed higher growth rate, improved feed conversion, and greater final body weight than the control (p < 0.05), indicating enhanced feed utilization efficiency and better overall performance. Gut morphology improved in MOS-fed treatments, with increased mucosal fold height and enterocyte height, suggesting increased nutrient absorption and improved gut functionality. Gut presumptive total count remained relatively stable among treatments, although Bacillus counts tended to increase with solubilized MOS supplementation. Under ammonia and nitrite stress, supplemented groups showed higher survival and reduced gill damage, indicating improved physiological tolerance and health status. Economic analysis demonstrated that 1.0 and 2.0 g kg⁻¹ MOS achieved the best cost–benefit ratios under intensive conditions. Overall, moderate MOS supplementation enhanced growth, gut morphology, stress resistance, and economic efficiency. Polynomial regression analysis, based on the four dietary inclusion levels evaluated, suggested that approximately 1.5 g kg⁻¹ MOS may represent an estimated optimal inclusion level.

The use of functional feeds in aquaculture has increased due to the reduction in fishmeal and the need to improve the gut health of farmed organisms. This study evaluated the effects of supplementing nucleotides (NT) and mannan oligosaccharide (MOS) in the diet of juvenile Penaeus vannamei reared in a synbiotic system for 60 days. Four treatments were tested: a control diet without additives (RC); a diet supplemented with 2 g NT kg⁻¹ (NT); a diet supplemented with 2 g MOS kg⁻¹ (MOS); and a diet supplemented with 1 g NT kg⁻¹ and 1 g MOS kg⁻¹ (NT/MOS). Water quality, zootechnical performance, gut morphology, microbiota indicators, and economic benefits were evaluated. There were no significant differences in water quality or production performance among treatments. However, additive supplementation improved economic efficiency and net revenue, with the NT/MOS treatment showing a 7.06% economic gain relative to the control. MOS supplementation increased the proportion of Bacillus spp. to 13.9 × 10⁷ CFU g⁻¹, suggesting a prebiotic effect and potential control of Vibrio spp. Morphologically, supplemented shrimp exhibited shorter mucosal folds and thicker gut walls. NT and MOS supplementation appeared to be an economically promising strategy for shrimp production in synbiotic systems.