Age-related oxidative stress and antioxidant capacity in heat-stressed broilers.

We aimed to evaluate the effects of acute heat stress (HS) and age on the redox state in broilers aged 21 and 42 days. We evaluated the expression of genes related to antioxidant capacity, the production of hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the liver, as well as oxidative stress markers in the liver and plasma. The experiment had a completely randomized factorial design with two thermal environments (thermoneutral and HS, 38°C for 24 h) and two ages (21 and 42 days). Twenty-one-day-old animals exposed to HS showed the highest thioredoxin reductase 1 (TrxR1) (P<0.0001) and glutathione synthetase (GSS) (P<0.0001) gene expression levels. Age influenced the expression of the thioredoxin (Trx) (P=0.0090), superoxide dismutase (SOD) (P=0.0194), glutathione reductase (GSR) (P<0.0001) and glutathione peroxidase 7 (GPx7) (P<0.0001) genes; we observed greater expression in birds at 21 days than at 42 days. Forty-two-day-old HS birds showed the highest H2O2 production (222.31 pmol dichlorofluorescein produced/min×mg mitochondrial protein). We also verified the effects of age and environment on the liver content of Glutathione (GSH) (P<0.0001 and P=0.0039, respectively) and catalase (CAT) enzyme activity (P=0.0007 and P=0.0004, respectively). Higher GSH content and lower CAT activity were observed in animals from the thermoneutral environment compared with the HS environment and in animals at 21 days compared with 42 days. Broilers at 42 days of age had higher plasma creatinine content (0.05 v. 0.01 mg/dl) and higher aspartate aminotransferase activity (546.50 v. 230.67 U/l) than chickens at 21 days of age. Our results suggest that under HS conditions, in which there is higher H2O2 production, 21-day-old broilers have greater antioxidant capacity than 42-day-old animals.

Monitoramento e conservação genética de populações naturais de Prochilodus lineatus dos rios Pardo, Mogi-Guaçu e Tietê, São Paulo / Monitoring and conservation genetics of Prochilodus lineatus wild populations of Pardo, Mogi Guaçu and Tiete rivers, São Paulo

O objetivo do presente estudo foi determinar a diversidade e a estrutura genética de seis populações naturais de Prochilodus lineatus em usinas hidrelétricas (UHE) dos rios Pardo (UHE Limoeiro - LMO), Mogi-Guaçu (UHE Mogi-Guaçu - MOG) e Tietê (UHE Promissão - PRO, UHE Barra Bonita - BAB, UHE Nova Avanhandava - NAV e UHE Bariri - BAR). Foi encontrado um total de 47 alelos, com tamanhos entre 118pb e 330pb. Os resultados de heterozigosidade média observada (0,490 a 0,625) refletiram uma alta variabilidade genética intrapopulacional. Os valores de distância genética (0,149 a 0,773), Fst (0,006 a 0,218) e Nm (1,2 a 4,2) mostraram a presença de similaridade genética entre as populações. De acordo com a AMOVA, houve maior variação dentro das populações do que entre elas. O dendograma mostrou a formação de dois agrupamentos (LMO-PRO-MOG e BAR-BAB-NAV). Concluiu-se que as populações naturais apresentaram alta variabilidade genética, com similaridade genética entre elas, possivelmente causada pelo programa de repovoamento realizado nesses rios.(AU)

The aim of this study was to determine the genetic diversity and structure of six wild populations of Prochilodus lineatus in Hydroelectric Power Plants (HPP) of the Pardo (HPP Limoeiro - LMO), Mogi Guacu (HPP Mogi-Guaçu - MOG), and Tiete (HPP Promissão - PRO, HPP Barra Bonita - BAB, HPP Nova Avanhandava - NAV and HPP Bariri - BAR) rivers. A total of 47 alleles, ranging in size from 118bp to 330bp were found. The results of observed heterozygosity average (0.490 to 0.625) reflected a high intra-population genetic variability. The values of genetic distance (0.149 to 0.773), Fst (0.006 to 0.218), and Nm (1.2 to 4.2) showed that between the populations there is genetic similarity. According to AMOVA there was higher variation within populations than between them. The dendrogram demonstrated the formation of two groups (LMO-PRO-MOG and BAR-BAB-NAV). It was concluded that wild populations had high genetic variability with genetic similarity between them, possibly caused by the restocking program performed in these rivers.(AU)