COMPREHENSIVE WELFARE ASSESSMENT OF RED KING CRAB (PARALITHODES CAMTSCHATICUS) DURING TRANSPORT AND STORAGE
Introduction
Long transportation of crustaceans naturally leads to the oppression of the organism. To optimize this process and improve the survival and viability requires a comprehensive assessment system for physiological state of animals, based on biochemical and behavioral indicators. All these parameters can be evaluated both in the laboratory and portable at any transport stage from the catch to delivery to the final consumer. To perform this assessment for the red king crab (Paralithodes camtschaticus) we selected biochemical parameters of hemolymph, such as glucose, lactate, urea, uric acid and total protein, as well as a number of motor reactions: moving mouthparts, antennas, scaphognathite and legs.
The purpose of this work was to compare two methods of red king crab's transportation by evaluating its physiological state with biochemical and behavioral indicators.
Methods and Materials
Commercial size red king crab males were transported during 30 hours from Bugoynes (Norway) to Moscow (Russia) with aircraft in foam boxes without water with wet foam filler and frozen gel. Within these commercial shipments several boxes were sent with dry foam filler. Contents of glucose, lactate, total protein, urea, and uric acid in hemolymph were determined spectrophotometrically using commercial reagent kits for clinical biochemistry.
To assess the behavioral indicators crabs were placed on a flat surface out of water. After that presence or absence of certain motor reactions were observed during 30 seconds, including attempts to move, motor activity of the limbs, antenna, mouthparts segments during stimulation and scaphognathite. Evaluation was carried out with 5-point scale. Each higher rating corresponded presence of one additional motor reaction (Table 1). The sample consisted 20 individuals for each type of transport and 50 control individuals.
Results and Discussion
Experiments showed that red king crabs may survive after transport in boxes with wet filler, and without it. However, the results do not allow any conclusions about crab's welfare and about the benefits of a particular transport options. Therefore, we carried out a comprehensive comparative evaluation. All crabs survived after transportation in both experimental groups. Table 2 shows the normal and critical values for selected biochemical parameters before and after transportation of red king crab.
During the experiments, in hemolymph of crab transported in boxes with wet material, the average content of glucose increased to 4,4±0,7 mmol/l, lactate to 2,89±0,53 mmol/l, total protein to 39,0±1.8 g/l, uric acid to 52,1±3,8 mmol/l. After transporting in boxes with dry material the concentration of glucose increased to 3,6±0,8 mmol/l, lactate to 2,78±0,47 mmol/l, total protein to 35,8±4,9 g/l, uric acid to 46,1±3,7 mmol/l. Urea content, which normally is 0,72±0,23 mmoles/l, after transportation with wet filler slightly increased to 0,83±0,14 mmol/l, and with dry filler decreased to 0,59±0 13 mmol/l. On average the accumulation of metabolic products was slower in crabs transported with dry filler.
Our developed method of estimating crab's welfare takes into account involuntary reflex reactions, such as the moving of scaphognathite and mouthparts segments in response to stimulation, as well as more complex motor responses like attempts to move. This method allows draw a conclusion on the conditions of transport by determining the activity of a small number of crabs from the party. The average activity score for crabs admitted to transportation shouldn't be less than 4 points. After experimental transportation with wet filler average score was 2,6±0,4, with dry filler 2,5±0,4.
Comparative evaluation of two types of transportation by both criteria showed no significant differences between them. On separate parameters transportation of red king crab in containers without water using dry filler has advantages over the traditional way of transportation in a wet environment.
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