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This study assessed the use of increasing levels of brown propolis extract (BPE) as a growth promoter in Nile tilapia ¢ngerling feeds. In a complete randomized design,75 Nile tilapia ¢ngerlings with 60 days on average and weighing 4.1 AE 0.1g were assigned to 25 aquaria (60 L) and subjected to 5 treatments in 5 repetitions for 30 days. Propolis from Serra do Araripe, Cariri Region, South Ceara Ł State^Brazil was used to produce the BPE. The treatments involved the addition of BPE to feed samples (0.91, 1.83, 2.74 and 3.65 g kg À 1 ) and feed control (without BPE). The ¢nal mean weight and the percentage of weight gain varied quadratically with the increase in BPE (Po0.01), with a maximum of 2.22 g kg À 1 . The other evaluated parameters were not a¡ected by the treatments (P40.05). The level of best performance parameters was 2.22 g kg À 1 , between the levels of 1.83 and 2.74 g BPE kg À 1 feed inclusion. These results indicate the potential to use the brown propolis extract as a growth promoter to Nile tilapia ¢ngerlings.

Pesq. Vet. Bras. 32(8) Multiple factors can be involved in the virulence processes of Aeromonas hydrophila. The objective of the present paper was to verify the presence of aerolysin, hidrolipase, elastase and lipase virulence genes through the polymerase chain reaction (PCR) in A. hydrophila isolates obtained from ϐish of the São Francisco River Valley, and to evaluate virulence according to the presence of these genes in Nile tilapia ϐingerlings. One hundred and fourteen isolates from the bacteria were used. DNA was heat extracted and PCR undertaken using speciϐic primers described in the literature. For in vivo tests Nile tilapia ϐingerlings were used. From the PCR tests, negative isolates for all genes tested were selected, positive isolates for two genes (aerolysin and elastase) and positive for the four genes tested. These were inoculated at a concentration of 10 8 UFC/ml into the tilapias, considered as treatments; another group of animals was used as control (with inoculation of saline solution). In all, 12 distinct standards regarding the presence of virulence factors in isolates from A. hydrophila, were observed. Of the 114 isolates analyzed, 100 (87.72%) presented at least one of the virulence factors under study. The virulence factors were widely distributed among the A. hydrophila isolates. Aerolysin was the most frequent virulence factor present in the isolates analyzed. A. hydrophila led to the mortality of the Nile tilapia ϐingerlings, regardless of the absence or quantity of virulence genes tested.INDEX TERMS: Aeromonas hydrophila, virulence factors, aerolysin, elastase, hidrolipase, lipase, Oreochromis niloticus.

Pythium insidiosum is a fungus-like organism present in subtropical and tropical areas, such as Brazil, known to infect humans and various animal species. P. insidiosum is the etiological agent of pythiosis, an emerging and granulomatous disease characterized mainly by cutaneous and subcutaneous lesions in horses, the principal species affected. Accurate diagnosis of pythiosis and identification of its causal agent by microbiological and serological tests can be often difficult and inconclusive principally for horses and humans. The aim of this study was to evaluate the application of the previously described P. insidiosum-specific nested polymerase chain reaction (PCR) assay to directly detect P. insidiosum DNA in clinical and experimental lesions. Universal fungal primers (ITS1 and ITS4) were used during the first-round of PCR to amplify ITS1, 5.8s, and ITS2. A second-round of PCR was conducted with P. insidiosum-specific primers (PI1 and PI2) to amplify a variable region within this ITS1. In this study, a total of 21 equine clinical samples (kunkers) and 28 specimens from experimentally infected rabbits were analyzed by nested PCR. The first-round of PCR generated 800-base pair products, and the second-round produced 105-base pair amplicons for each P. insidiosum-specific sample; no amplicons were generated in negative control samples. Our results suggest that nested PCR is an important and efficient tool for diagnosis of both endemic (horse samples) and experimental (rabbit samples) pythiosis.

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