ABSTRACT This study aimed to evaluate the hematological profile and relative condition factor of naturally parasitized Nile tilapia from 12 fish farms in southern Brazil. A total of 240 fish were collected from four regions of the state of Santa Catarina. They were anesthetized, and the blood was collected by puncturing the caudal vein. Subsequently, the fish were necropsied for parasitological analysis. The results were compared with the Kruskal-Wallis test, and the correlations were verified with the Spearman test (P ˂ 0.05). The parasitological analysis revealed high infestations by Ichthyophthirius multifiliis on the fish gills of the south and west regions. The presence of Trichodina magna and Trichodina compacta was observed in low intensity on the body surface of fish from all facilities. Trichodina spp. was found in high intensity parasitizing the fish gills of northern, Itajaí valley and western regions, nonetheless, in those regions, the presence of Monogenea, Cichlidogyrus sclerosus, and Cichlidogyrus halli, on fish gills was observed. The hematological profile presented altered parameters, featuring monocytosis and thrombocytopenia, possibly associated with high parasitic intensities. The observed correlations suggest that neutrophils and monocytes are directly involved in an organic defense against parasites. Monocytes are mainly targeted in the defense against I. multifiliis.

RESUMO: A dieta suplementada com a bactéria probiótica Weissella cibaria sobre a eficácia da imunização de surubim híbrido contra a septicemia hemorrágica específica, causada por Aeromonas hydrophila, foi avaliada nos seguintes tratamentos: peixes alimentados com a dieta suplementada com probiótico, peixes vacinados, peixe vacinadas que receberam um probiótico na dieta e peixes não tratados (controle). Peixes dos tratamentos probióticos foram alimentados com uma dieta contendo W. cibaria por 41 dias. No 15o dia do experimento, os peixes dos tratamentos de vacinas foram vacinados intraperitonealmente, com posterior reforço oral por quatro dias. Uma semana após o reforço oral, três peixes de cada unidade experimental foram amostrados. A suplementação de probiótico aumentou o número de trombócitos e concentração lisozima em comparação com surubins que não receberam W. cibaria na dieta. Por outro lado, a vacinação influenciou no aumento do título de aglutinação, a concentração de lisozima e a atividade antimicrobiana, em comparação com os surubins que não foram vacinados. No entanto, não houve interação entre a dieta com probióticos e vacinação no híbrido surubim nos parâmetros analisados.

ABSTRACT: A supplementary diet with the probiotic bacteria Weissella cibaria on the efficacy of surubim hybrid immunization against a specific hemorrhagic septicemia caused by Aeromonas hydrophila was evaluated on the following treatments: fish fed a supplemented probiotic diet, vaccinated fish and vaccinated fish fed a supplemented probiotic diet, and untreated fish (control). Fish from the probiotic treatments were fed a diet containing W. cibaria for 41 days. On the 15th day of the experiment, fish from vaccine treatments were intraperitoneally vaccinated, with posterior oral booster for four days. One week after the oral booster, three fish from each experimental unit were sampled. The probiotic supplementation increased the number of thrombocytes and lysozyme concentration compared with surubim that did not receive W. cibaria in the diet. On the other hand, the vaccination increased agglutination titer, lysozyme concentration, and antimicrobial activity compared with surubim that were not vaccinated. However, there was no interaction between diet with probiotics and vaccination in the surubim hybrid in the analysed parameters.