Resumo O objetivo deste trabalho foi avaliar a termonarcose como método de insensibilização em tilápia-do-nilo (Oreochromis niloticus) e seu efeito sobre o pH e as bases nitrogenadas voláteis totais no filé congelado. Para avaliação, 60 animais foram divididos em seis faixas de temperatura: 0‒1ºC, 1‒2ºC, 2‒3ºC, 3‒4ºC, 4‒5ºC e 5‒6ºC. Utilizou-se um tanque de insensibilização com uma mistura de água e gelo (1:1). A temperatura foi monitorada constantemente, e gelo foi adicionado sempre que necessário para manter as diferentes faixas de temperatura. Os peixes submetidos à 0-3ºC perderam os sinais de sensibilidade mais rapidamente, em 270,3 s. Não houve alteração das características dos filés quanto aos valores de pH (6,86 a 7,00) e das bases nitrogenadas voláteis totais (6,36 a 8,61 mg 100 g-1 de N), ambos de acordo com o estipulado pela legislação vigente no Brasil. Como método de insensibilização, a termonarcose é eficaz à temperatura de 0-3ºC e não afeta a qualidade do filé congelado de tilápia-do-nilo. tilápiadonilo tilápia nilo Oreochromis niloticus avaliação 6 01ºC ºC 0 1ºC 0‒1ºC 12ºC 1 2ºC 1‒2ºC 23ºC 2 3ºC 2‒3ºC 34ºC 3 4ºC 3‒4ºC 45ºC 4 5ºC 56ºC 5 6ºC 5‒6ºC Utilizouse Utilizou se 11. 11 . (1:1) constantemente 03ºC rapidamente 2703 270 270, s 6,86 686 86 (6,8 7,00 700 7 00 6,36 636 36 (6,3 861 8 61 8,6 10 g1 g g- N, N , N) Brasil tilápiadonilo. nilo. (1:1 27 6,8 68 (6, 7,0 70 6,3 63 8, (1: 6, (6 7, (1 (

Abstract The objective of this work was to evaluate thermonarcosis as a stunning method for Nile tilapia (Oreochromis niloticus) and its effect on the pH and total volatile basic nitrogen in the frozen fillets. For evaluation, 60 animals were divided into six temperature ranges: 0‒1ºC, 1‒2ºC, 2‒3ºC, 3‒4ºC, 4‒5ºC, and 5‒6ºC. A stunning tank with a mixture of water and ice (1:1) was used. The temperature was monitored constantly, and ice was added as needed to maintain the different temperature ranges. The fish subjected to 0‒3ºC were desensitized more quickly, in 270.3 s. There was no change in the characteristics of the fillets regarding the values of pH (6.86 to 7.00) and total volatile nitrogen bases (6.36 to 8.61 mg 100 g-1 N), both in accordance with the stipulated by the current Brazilian legislation. As a stunning method, thermonarcosis is efficient at a temperature from 0-3ºC and does not affect the quality of the frozen fillets of Nile tilapia. Oreochromis niloticus evaluation 6 ranges 01ºC ºC 0 1ºC 0‒1ºC 12ºC 1 2ºC 1‒2ºC 23ºC 2 3ºC 2‒3ºC 34ºC 3 4ºC 3‒4ºC 45ºC 4 5ºC 4‒5ºC 56ºC 5 6ºC 5‒6ºC 11 (1:1 used constantly 03ºC quickly 2703 270 270. s 6.86 686 86 (6.8 7.00 700 7 00 6.36 636 36 (6.3 861 8 61 8.6 10 g1 g g- N, N , N) legislation (1: 27 6.8 68 (6. 7.0 70 6.3 63 8. (1 6. (6 7. (

Abstract The objective of this study was to evaluate the genetic diversity of Moraxella bovis and Moraxella bovoculi bacteria isolated from infectious bovine keratoconjunctivitis (IBK) outbreaks in the state of Rio Grande do Sul, Brazil. The genetic diversity among Moraxella spp. was evaluated by RAPD-PCR, JWP1-JWOPA07-PCR, ERIC-PCR and by sequencing the 16S-23S intergenic regions. Based on the dendrogram, two genetically differentiated clades were observed; 14 isolates were classified as M. bovis and 17 as M. bovoculi. Genetic distances between the M. bovis samples ranged from 0.0379 to 0.4285, while for M. bovoculi the dissimilarities ranged from zero to 0.7297. Alternatively, based on sequencing analyses of the 16S-23S intergenic region, M. bovis and M. bovoculi isolates were grouped into the same two different clades, but it was not possible to differentiate between isolates within clades. PCR techniques were demonstrated to be a satisfactory tool to unravel the genetic variability among Moraxella spp., while sequencing of the 16S-23S intergenic region was only able to differentiate two species of the Moraxella genus. Despite sampling geographically close regions, we demonstrate considerable genetic diversity in M. bovis and M. bovoculi strains and genetically distinct M. bovis strains co-infecting the same animal.