Investigation of the mechanisms involved in the transport and deposition astaxanthin in Atlantic salmon (Salmo salar) and cod (Gadus morhua)
Astaxantin (Ax) is a xanthophyll carotenoid naturally produced from microalgae, phytoplankton, and yeast. The accumulation of this pigment in the muscle of Atlantic salmon and other salmonids species is the reason of their characteristic red/pink flesh. The effect of Ax on muscle coloration assume a noteworthy importance in the fish industry, since the color intensity of the fillet, together with fat content and texture are the major parameters that determine the satisfaction of the costumer and thus the fish value on the market. Furthermore, in fish xanthophylls act as precursor for vitamin A production. Ax is also one of the most powerful natural antioxidant and researches have already proved its positive effect on stress and disease resistance in both aquatic and non-aquatic species.
Fish cannot produce carotenoids de novo and in farmed conditions diet supply is the only source of carotenoids. However, despite fed with Ax enriched feeds, salmonids approximately retain only between 2 and 22 % of the pigment in the flesh (12% A. salmon). Intestinal absorption, transport and metabolism of Ax are the main factors responsible for the pigments retention in the muscle. Nevertheless, the mechanism involved in these processes are jet far to be clear.
Salmonids are unique to accumulate carotenoids in the muscle. Unfortunately, the mechanisms behind the deposition differences between white and pink-flesh fish are not clear.
In this experiment, by a comparative approach, seawater Atlantic salmon, will be studied together with cod. A number of 90 salmon and 90 cod (1kg each) will be divided in 12 thanks (15fish/tank, 6 tank per species) acclimatized for two weeks and then treated as follow: Two tanks fed with low lipid diet pellet; Two tanks fed with low lipid diet pellet coated with oil and Ax; Two tanks fed with low lipid diet pellet and fish injected intraperitoneally with Cartophily Pink (Ax). The intraperitoneal injection will be performed by injecting in the fish abdominal cavity 50 mg of pigment dissolved in buffered saline solution. The first, the third week and one month after the injection it will be sampled 5 fish per tank. For each fish there will be collected blood and muscle tissue samples.
This experiment will attempt to clear mechanisms and differences, like timing of absorption, transport, up-take and/or Ax conversion in other metabolites between the two species.
REFINEMENT: Animals’ distress will be reduced to the minimum and unnecessary pain will be avoided. Therefore, when transported in the experimental tanks and before the procedure of intraperitoneal injection fish will be slightly anesthetized. Instead, during sampling, fish will be netted and sacrificed by an overdose of anesthetic.
REPLACEMENT: The experimental models were chosen in order to use farmed instead of wild stocks. Furthermore, understanding the physiology involved in the transport and deposition of astaxanthin in salmon muscle is critical to improve the fish welfare, the quality of the product and the farmers’ economic benefits.
REDUCTION: The number/biomass of fish is chosen in order to have stable behavior in the tanks and strong analytical results.
Fish cannot produce carotenoids de novo and in farmed conditions diet supply is the only source of carotenoids. However, despite fed with Ax enriched feeds, salmonids approximately retain only between 2 and 22 % of the pigment in the flesh (12% A. salmon). Intestinal absorption, transport and metabolism of Ax are the main factors responsible for the pigments retention in the muscle. Nevertheless, the mechanism involved in these processes are jet far to be clear.
Salmonids are unique to accumulate carotenoids in the muscle. Unfortunately, the mechanisms behind the deposition differences between white and pink-flesh fish are not clear.
In this experiment, by a comparative approach, seawater Atlantic salmon, will be studied together with cod. A number of 90 salmon and 90 cod (1kg each) will be divided in 12 thanks (15fish/tank, 6 tank per species) acclimatized for two weeks and then treated as follow: Two tanks fed with low lipid diet pellet; Two tanks fed with low lipid diet pellet coated with oil and Ax; Two tanks fed with low lipid diet pellet and fish injected intraperitoneally with Cartophily Pink (Ax). The intraperitoneal injection will be performed by injecting in the fish abdominal cavity 50 mg of pigment dissolved in buffered saline solution. The first, the third week and one month after the injection it will be sampled 5 fish per tank. For each fish there will be collected blood and muscle tissue samples.
This experiment will attempt to clear mechanisms and differences, like timing of absorption, transport, up-take and/or Ax conversion in other metabolites between the two species.
REFINEMENT: Animals’ distress will be reduced to the minimum and unnecessary pain will be avoided. Therefore, when transported in the experimental tanks and before the procedure of intraperitoneal injection fish will be slightly anesthetized. Instead, during sampling, fish will be netted and sacrificed by an overdose of anesthetic.
REPLACEMENT: The experimental models were chosen in order to use farmed instead of wild stocks. Furthermore, understanding the physiology involved in the transport and deposition of astaxanthin in salmon muscle is critical to improve the fish welfare, the quality of the product and the farmers’ economic benefits.
REDUCTION: The number/biomass of fish is chosen in order to have stable behavior in the tanks and strong analytical results.