Spatio-temporal variation in serum chemistry of the lobster, Homarus americanus Milne-Edwards

The effects of claw ligatures in American lobster (Homarus americanus) storage: a preliminary study of haemolymph parameters

American lobsters are crustaceans that are offered for sale live and are stored in controlled temperature recirculating aquaria. During marketing, they are subjected to stressors that can affect their welfare, such as air exposure, confinement, and handling. European legislation does not provide specific criteria or retention requirements, and so their management depends largely on the common sense of food business operators. Claw ligatures before and during storage are not legally required but are recommended because they prevent lobsters from damaging each other and ensure workers’ safety. The aim of the present study is to evaluate the effect of claw ligatures on the lobsters’ welfare by analysing eight different haemolymph stress indicators, vitality, and weight. The calcium level showed significant differences in the two experimental groups (P < 0.05). Our results suggested that the absence of rubber bands did not offer any significant contribution to the lobsters’ welfare.

Differential metabolite levels in response to spawning-induced inappetence in Atlantic salmon Salmo salar

Atlantic salmon Salmo salar undergo months-long inappetence during spawning, but it is not known whether this inappetence is a pathological state or one for which the fish are adapted. Recent work has shown that inappetent whale sharks can exhibit circulating metabolite profiles similar to ketosis known to occur in humans during starvation. In this work, metabolite profiling was used to explore differences in analyte profiles between a cohort of inappetent spawning run Atlantic salmon and captively reared animals that were fed up to and through the time of sampling. The two classes of animals were easily distinguished by their metabolite profiles. The sea-run fish had elevated ɷ-9 fatty acids relative to the domestic feeding animals, while other fatty acid concentrations were reduced. Sugar alcohols were generally elevated in inappetent animals, suggesting potentially novel metabolic responses or pathways in fish that feature these compounds. Compounds expected to indicate a pathological catabolic state were not more abundant in the sea-run fish, suggesting that the animals, while inappetent, were not stressed in an unnatural way. These findings demonstrate the power of discovery-based metabolomics for exploring biochemistry in poorly understood animal models.

Effects of short time UV-A exposures on compound eyes and haematological parameters in Procambarus clarkii (Girad, 1852)

The amount of ultraviolet radiation (UVR) reaching the Earth's surface has been increasing as a result of an increasingly thinner ozone layer. The UV-A component of the UVR is able to generate oxidative stress in the compound eye and haemolymph of Procambarus clarkii when the latter was exposed for as little as 15 min daily for one week to UV-A. Changes in the eye involved corneal material, crystalline cones, pigments in cone stalks and retinula cells, rhabdom integrity, haemocyte infiltration, and haemal spaces. UV-A had significant impacts on haemolymph iron and glucose, whereas Ca ions were unaffected. Total protein and Cu-ions showed only insignificant changes following UV-A radiation. Involvement of lipid peroxidation and DNA fragmentation was significant with regard to the tissue damage cause by the UV-A. UV-A furthermore induced biological effects on serum electrophoretic patterns: some fractions either increased in size or others decreased. The described changes can be used as reference guidelines in evaluations of UV-A induced stress effects in P. clarkii.

Naturally occurring bacteraemia in American lobsters, Homarus americanus Milne-Edwards, in Long Island Sound

The health status of the American lobster, Homarus americanus Milne-Edwards, in Long Island Sound (LIS) has been in decline, with seasonal mortality events occurring since 1998. In order to assess the potential effects of environmental conditions on lobster health via haemolymph analysis, lobsters collected from various sites in LIS were examined and sampled while concurrent environmental data (water temperature, salinity and dissolved oxygen) were recorded. The pH of the haemolymph of each lobster was tested, followed by a collection of haemolymph for serum biochemistry analysis and bacterial culture. This report focuses on the results of the bacterial sampling. The majority of bacteria cultured were opportunistic pathogens commonly found in the environment, including some that are associated with sewage and pollution. The prevalence of bacteraemia was correlated with the site of collection, the month in which the lobsters were sampled, and water temperature.