This study evaluated the ectoparasite distribution on the gill archs of pond-reared pacu (Piaractus mesopotamicus Holmberg, 1887), hybrid patinga (P. mesopotamicus female x P. brachypomus (Cuvier, 1817) male), hybrid tambacu (Colossoma macropomum (Cuvier, 1816) female x P. mesopotamicus male) and hybrid surubim (Pseudoplatystoma reticulatum female x P. corruscans Spix & Agassiz, 1829 male). A t...

Gas exchange across fish gills is reviewed and the respiratory and cardiovascular changes associated with exercise and hypoxia described. Heart rate is controlled by inhibitory vagal cholinergic activity which increases during hypoxia and decreases during exercise. Stimulation of receptors on the first gill arch during hypoxia initiates bradycardia. The increase in stroke volume during hypoxia ...

Artificial oscillation imposed onto the gill arches could modify the respiratory rhythm in the carp Cyprlnus carpio. The degree of modification depended upon the frequency and amplitude of the applied movement. Oscillation at frequencies close to the spontaneous respiratory rhythm and at amplitudes in the range of 2-3 mm resulted in a cyclic pattern of lengthening and shortening of the breathin...

In the aquatic environment, despite the presence of constitutive or enhanced antioxidant defence systems, increased levels of oxidative damage will occur in organisms exposed to contaminants that stimulate the production of reactive oxygen species. The increased ROS production and subsequent oxidative stress has been associated with a pollutant-mediated mechanism of toxicity in fish organs. The...

Gill disease of fry and fingerlings associated with extensive mortality in rainbow trout freshwater farms in Denmark have been observed on an increasing number of occasions in the latest years. Clinical symptoms of hyperventilation indicate respiratory distress. Gross-pathological observations of gills show pale nodules and patches on gill filaments. Histological and scanning electron microscop...

Structural differences were identified in gill DNA from two groups of English sole collected from Puget Sound, Washington, in October 2000. One group was from the industrialized Duwamish River (DR) in Seattle and the other from relatively clean Quartermaster Harbor (QMH). Chemical markers of sediment contamination [e.g., polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PC...

Neoparamoeba spp. are amphizoic amoebae with the capacity to colonize the gills of some marine fish, causing AGD. Here, the gill tissue transcriptome response of Atlantic salmon (Salmo salar L.) to AGD is described. Tanks housing Atlantic salmon were inoculated with Neoparamoeba spp. and fish sampled at time points up to 8 days postinoculation (pi.). Gill tissues were taken from AGD-affected fi...

Bacterial diseases in cultured fish are considered the main problem with aquaculture system in Iran. The gills are multifunctional organs responsible for respiration, osmoregulation, nitrogenous waste excretion, and acid-base balance. Moreover, they are very sensitive to water contamination. Aeromonas hydrophila (A. hydrophila) is an opportunist pathogen responsible for ...

In some clinical trials, repeated occurrences of the same type of event are the study endpoint. For example, numbers of adverse event of interest occurred during the study period. There are several standard statistical methods for the analysis of such data, including the Anderson-Gill model (Anderson and Gill, 1982) and the Poisson regression model (Frome et. al. 1973). Signorini (1991) has pro...

Myxosporeans are best known for the diseases they cause in commercially important fish species. Identification of myxosporeans at the species-level is mainly based on conventional methods. The 18S rRNA gene sequence of morphologically identified Myxobolus orissae infecting the gill lamellae of mrigal carp Cirrhinus mrigala was characterized in the present study. The plasmodia of M.orissae were ...