RESUMEN
Ichthyophthirius multifiliis is a parasite that poses a considerable threat to aquaculture and the ornamental fish industry, but with limited effective treatment options available. This study employed RT-qPCR to detect and analyze the expression changes of partial toll-like receptor (TLR) genes (TLR1 and TLR21), adapter protein and signal transduction molecule genes (MyD88, TRIF, NF-κB, IRAK4, and IRF3), and cytokines (IL-6, IL-8, IL-13, CXC-α and CXCR1), as well as complement C3, in the skin, gill, fin, liver, head kidney and spleen of Rhinogobio ventralis under different infection conditions. Additionally, tissue sections and scanning electron microscopy were utilized to observe the pathological changes in the gills and fins of R. ventralis after infection with I. multifiliis. The expression patterns of TLR-related DEGs (differentially expressed genes) in diseased wild fish were analyzed, revealing upregulation of TLR1, TLR21, MyD88, NF-κB, IRAK4, TRIF, IRF3, IL-6, IL-8, IL-13, CXC-α, CXCR1, and C3 genes in various tissues, indicating that these genes may be involved in the immune response of R. ventralis to I. multifiliis infection. To further analyze the gene expression of sampled from the field, an artificial infection model of R. ventralis was established under laboratory conditions, with additional sampling from the skin and fins. These genes continued to show varying degrees of upregulation, but the results were not entirely consistent with those from Wudongde samples, which may be due to the more complex environment in the wild or differences in the degree of I. multifiliis infection in wild fish. The infection of I. multifiliis caused severe damage to the gills and fins of R. ventralis, characterized by extensive secretions on the gill and fin surfaces, with the presence of attached I. multifiliis trophonts, including damage and loss of gill filaments, swollen gill lamellae, and deformed gill plates, as well as cell proliferation and necrosis of gill epithelial cells. This study sheds light on the role of the TLR signaling pathway in resisting I. multifiliis infection and its associated histopathological changes in R. ventralis, providing valuable insights for the prevention and treatment of I. multifiliis infection in R. ventralis.
Asunto(s)
Infecciones por Cilióforos , Enfermedades de los Peces , Proteínas de Peces , Hymenostomatida , Inmunidad Innata , Animales , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/parasitología , Hymenostomatida/fisiología , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Infecciones por Cilióforos/veterinaria , Infecciones por Cilióforos/inmunología , Inmunidad Innata/genética , Perfilación de la Expresión Génica/veterinaria , Receptores Toll-Like/genética , Receptores Toll-Like/inmunologíaRESUMEN
The aim of this study is to evaluate the application of magnetic resonance imaging (MRI) to assess ovarian maturation in live female Rhinogobio ventralis (Sauvage & Dabry de Thiersant, 1874). The fish were randomly collected from the Jiangjin area of the Yangtze River between January and April 2014. Magnetic resonance imaging was performed using a 3.0 T clinical MRI scanner with a brain coil and two pulse sequences (IDEAL and 3D CUBE) were employed. Magnetic resonance and histologic images at different stages of ovarian maturation (I-IV) were acquired. An empirical equation (y = -0.1 + 1.56 × x) was derived by traditional method to describe the relationship between the gonadosomatic index (y) and the percentage volume of the ovary (x). A significant correlation (R(2) = 0.977, P < 0.01, N = 53) was found between measurements of the percentage volume of the ovary by MRI and traditional methods. The research findings suggested that MRI was a reliable, rapid, and noninvasive method to assess stages of ovarian maturity in female R. ventralis.
Asunto(s)
Peces/fisiología , Imagen por Resonancia Magnética/veterinaria , Ovario/diagnóstico por imagen , Ovario/fisiología , Maduración Sexual/fisiología , Animales , Femenino , Peces/anatomía & histologíaRESUMEN
Rhinogobio ventralis, a small-sized economic fish living in the bottom of the fast-flowing water, has a limited geographical distribution in the upper reaches of Yangtze River in China. The complete mito-genome of R. ventralis is 16,607 bp in length, containing 37 genes of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and a control region (D-loop). The gene order and composition of R. ventralis is similar to that of most other fishes, and its nucleotide composition is 31.10% A, 26.64% T, 26.28% C and 15.98% G, with a slight AT bias of 57.74%. It is first report of the complete mitochondrial genome in the bottom dwelling Rhinogobio species.