The Effect of Temperature on the Physiological Condition and Immune-Capacity of European Lobsters (Homarus gammarus) During Long-Term Starvation

Abstract

Decapod crustaceans, such as those from the Homarus genus, are key benthic representatives that support very valuable fishing and aquaculture industries. Those commercially caught, such as the European lobster (H. gammarus) can be stored in live facilities for short (a few days) to long periods (up to 6 months) before being traded. Conditions in captivity are not standardized, including holding temperatures or feeding regimes. Herein, the physiological condition during long-term starvation (24 weeks) in H. gammarus was assessed at three temperatures (4, 8, and 12 • C). Our results indicate that, H. gammarus have the capacity to endure long-term starvation. Principal component analysis (PCA) of measured parameters showed two main components (Eigen value >1). Fasted animals kept at 12 • C, separated from all other experimental groups due to higher total phenoloxidase (PO) activity in the hemolymph and water content in the muscle, suggesting that keeping H. gammarus un-fed at this higher temperature is physiologically more demanding and detrimental. This was later confirmed by significant changes, particularly in this group, in the histology and lipid class composition of the hepatopancreas. These data call into question the suitability of current accepted in vivo condition markers (e.g., hemolymph protein concentration) to determine the physiological condition and welfare of decapods such as H. gammarus.

Welfare in Farmed Decapod Crustaceans, With Particular Reference to Penaeus vannamei

“…Decapod species, like any other organism, respond to stressors by mounting a stress response that involves behavioural and physiological changes at multiple biological levels. The concept of finding suitable biomarkers that can be applied in the context of decapod welfare has been mentioned in few studies (Rosas et al, 2004;Ciaramella et al, 2014;D'Agaro et al, 2014;Albalat et al, 2019). However, there is little evidence that a concerted effort has been made to establish haematologic biomarkers or reference intervals for decapods, more specifically Penaeus spp., in captivity or under cultivation.…”

“…These procedures are invasive, but not lethal, in the right hands. Some such measures have been used in an attempt to disentangle 'captivity-associated stress' in crabs (e.g., Cancer pagurus; Johnson et al, 2016) and lobsters (e.g., Homarus gammarus, Basti et al, 2010;Albalat et al, 2019). Haemolymph biochemical parameter assessment has been trialled with autoanalyzers (haemocytes) and handheld refractometers, e.g., crayfish (Astacus leptodactylus) and lobsters (H. americanus) (Sepici-Dincȩl et al, 2013;Wang and McGaw, 2014).…”

Metabolic reprogramming in crustaceans: A vital immune and environmental response strategy

“…66 Generally, diseases result from an organism's inability to cope with changes in the internal and external environments. 81 Moreover, changes in the external environment such as salinity, 63,[82][83][84] dissolved oxygen (DO), [85][86][87][88] temperature, [89][90][91][92] ammonia nitrogen, 93 nitrites, 94 heavy metals, 95,96 toxic chemicals 97 and biological pollutants 98 have an influence metabolism, which consequently affects immune response (Table 2).…”

“…japonicus ) changed significantly, downregulation of genes involved in energy metabolism pathways in hepatopancreas 91 . When European lobster ( Homarus gammarus ) were starved and/or subjected to low thermal stress (4, 8 and 12℃), cumulative mortality and total haemolymph phenol oxidase (PO) activity of the 12℃ fasted group increased significantly, whereas fat content (especially triacylglycerols) was significantly decreased 92 . Thus, thermal stress has both beneficial and adverse effects on crustaceans, depending on the physiological state.…”

Replacement of Antarctic krill (Euphausia superba) by extruded feeds with different proximate compositions: effects on growth, nutritional condition and digestive capacity of juvenile European lobsters (Homarus gammarus, L.)

“…However, maximum size per se does not necessarily imply the best condition. This is particularly relevant in decapod crustacean species since their body weight is highly influenced by the water content and moulting stage (30) . The use of biochemical indicators can aid in a more comprehensive evaluation of the nutritional status of the reared animals.…”