The lysozyme of the plaice Pleuronectes platessa L

Variations of serum and mucus lysozyme activity and total protein content in the male and female Caspian kutum (Rutilus frisii kutum, Kamensky 1901) during reproductive period

Serum and mucus lysozyme were measured in male and female Caspian kutum (Rutilus frisii kutum) under seasonal temperature, gonadal growth and reproductive migration. Significant difference with almost similar trend in serum and mucus lysozyme of the female Caspian kutum in sampling time and ovarian growth was observed. However, while there was no significant difference in serum lysozyme of the male specimen in sampling time and testicular growth, significant variations was observed in mucus lysozyme. In addition, there was significant difference in mucus total protein both for male and female specimens. The effectiveness ratio of factors on lysozyme variations followed in descending order by seasonal temperature (main factor), reproductive activity and migration with negligible effect and the lysozyme level was not significantly different in male and female Caspian kutum.

Influence of melatonin on the immune system of fish: a review

Endocrine-immune system interactions have been widely demonstrated in mammals, whereas in fish, these relationships remain unclear. Of the organs that constitute the endocrine system, the pineal gland and its secretory product melatonin act in the synchronization of daily and seasonal rhythms in most vertebrates, including fish. Seasonal differences in immunocompetence and disease prevalence have been well documented in humans. Seasonality also strongly influences the life history of fish by controlling the timing of physiological events, such as reproduction, food intake, locomotor activity, and growth performance. Apart from its synchronizing capabilities, the role of melatonin in physiological processes in fish is not thoroughly understood. The purpose of this review is to summarize current studies on the effects of melatonin on the fish immune system. These studies suggest that melatonin represents an important component of fish endocrine-immune system interactions. The elucidation of the defense mechanisms of fish will facilitate the development of health management tools to support the growing finfish aquaculture industry as well as address questions concerning the origins and evolution of the immune system in vertebrates.

Seasonal effects on hematological and innate immune parameters in sea bass Dicentrarchus labrax

The temperate aquatic environment is affected by two primary components of season, temperature and photoperiod, during the annual cycle. Many organisms respond to seasonal change physiologically, behaviorally or both. The aim of this study was to investigate the effect of seasonality on cortisol, hematological and innate immune parameters in European sea bass reared under traditional semi-intensive aquaculture. Sea bass (Dicentrarchus labrax) were reared in an outdoor pond and serum cortisol, hematocrit, leucocrit, serum lysozyme activity and total glutathione were bimonthly monitored over a 14-months period. The effect of seasonality was observed for all parameters carried out, with generally higher values in summer and lower in winter. These results could improve the understanding of the influence of seasonal cues on the immune system and hematological parameters in fish in order to optimize the husbandry practices.

The effect of seasonality on normal haematological and innate immune parameters of rainbow trout Oncorhynchus mykiss L

It is well established that seasonality dominates the life history of fish by controlling the timing of physiological events such as reproduction, food intake, locomotor activity and growth performance. Seasonal differences in immune competence and prevalence of disease have been well documented in humans. The aim of this study was to determine if season influences the immune response of rainbow trout (Oncorhynchus mykiss L.). Thus, a 12-month trial was carried out in which plasma lysozyme activity and respiratory burst of head kidney macrophages (two innate immune parameters) and total red and white blood cell counts (two haematological parameters) were monitored at monthly intervals. Since photoperiodic information is thought to be conveyed via melatonin secretion, plasma melatonin levels were also measured at four seasonal points (day and night). A general seasonal influence was observed in the parameters measured in these fish, with the exception of respiratory burst activity of head kidney macrophages, with the parameters highest in summer and lowest in winter for total white blood cell counts and lysozyme activity.

Seasonal variation and the immune response: a fish perspective

The environment in which an animal lives affects the physiology and psychology of that animal. The greater the distance from the equator the more profound this influence becomes, as the environment becomes more variable over the years. Temperature, photoperiod, precipitation and other environmental conditions, which are directly or indirectly controlled by the season, can affect an animal. It is becoming apparent that these conditions may impact on the immune system, and this can affect animal health. This review looks at the known mechanisms for transducing environmental cues and how these can affect immune parameters and function. The main focus is fish, especially in relation to aquaculture and the associated disease risks. Work on other animal classes is included for comparison.

Biochemical effects of long-term exposure to cadmium and copper on rainbow trout (Salmo gairdneri): validation of water quality criteria

Salmo gairdneri specimens were exposed for 4 months to 1-10 micrograms/liter of Cd and 30-100 micrograms/liter of Cu. At different times from the beginning of the experiment the activity of some metal-sensitive enzymes was assayed (blood catalase and carbonic anhydrase; liver aminolevulinate dehydrase and total leucylaminopeptidase ). Biochemical indices of mitochondrial (respiratory control ratio; O2 consumption) and lysosomal function (percentage free leucylaminopeptidase activity), gill sialic acid content, and mucus lysozyme concentration were also detected. Cu (at both the levels tested) and Cd (only at the highest concentration) cause a remarkable alteration in various biochemical/physiological parameters under study. Considerations about the water quality criteria levels proposed by EIFAC /FAO for the two metals are reported.