| Seahorses(Hippocampus spp.),a group of small fishes which are used a traditional Chinese medicine,are widely distributed in shallow waters along the coast of tropical,subtropical and warm temperate regions.The study on seahorse's biochemistry is important to understand its nutritional and functional value.Some factors(such as seahorse species,size,gender,diet,salinity,temperature,etc.)may affect the composition and content of biochemical components and nutritional value.In the present study,the biochemical composition and contents of two species(H.erectus and H.trimaculatus)in different genders,reared diet and growth stage(H.erectus)were comapred.1.A comparative analysis of functional components and nutritional value of female and male in two species(H.erectus and H.trimaculatus)To analyze the nutritional and functional components of seahorses,especially the differences between the females and males,we analyzed the contents of nutritional and functional ingredients of two popular species,H.erectus and H.trimaculatus.The nutritional value was evaluated as well.The results show that(1)the major component of the seahorses was crude protein(dry weight)which averaged at 60.61±2.83 %;the crude fat of seahorses was relative lower with the average content of 3.04±0.26 %,and there was no significant differences between the genders within a species.(2)The males and the females were similar in the amino acid compositions;within a species,the amino acids score,chemical score and essential amino acid index of the females were higher than the males.(3)The fatty acid compositions in the seahorses were consistent regardless of gender,and the total contents of saturated fatty acids,monounsaturated fatty acids and polyunsaturated fatty acids(PUFA)of the females were significantly higher than the males within a species;the ratio of n-6/n-3 PUFA of two species was 0.14-0.18,and these are n-3 PUFA-rich food.(4)The contents of cholesterol and hypoxanthine in the females were significantly higher than the males,while the uridine in the females was lower than the males.The results indicate that the gender difference in the contents of nutrients and main functional components(cholesterol and hypoxanthine),suggesting that mono-sex culture might be a good practice in seahorse aquaculture.2.Effect of diets on the biochemical composition of the lined seahorse(H.erectus)The effects of three diets(live adult Artemia spp,frozen Mysis spp.and live Mysis spp.)on the biochemical composition(including crude composition,cholesterol,amino acids,fatty acids,mineral elements and nucleoside)were investigated in H.erectus,and nutritional value of three diet groups were evaluated and compared.The results show that(1)contents of nutritional components in three groups were not significant.(2)The composition of amino acids and mineral elements were consistent in three groups,and the first limiting amino acid was tryptophan.The highest levels of constant and trace elements were Ca and Zn,respectively.Most abundant biochemical component of fatty acid and nucleotide were seahorses with Artemia spp.and live Mysis spp.as bait respectively.The essential amino acids(excepted phenylalanine),total amino acid(?AA),?SFA,?PUFA,EPA,DHA and the content of cholesterol in the live Mysis spp.group were significantly higher than the groups of Artemia spp.and frozen Mysis spp..The proportion of the essential amino acids(?EAA/?NEAA,?EAA/?AA)in live Mysis spp.group was better than the Artemia spp.and the frozen Mysis spp.groups.(3)The lined seahorse is rich in aroma-related substances such as arginine,n-3 PUFA,cholesterol,Zn and Se.The content of arginine,n-3 PUFA and cholesterol in the lined seahorse was the highest with live Mysis spp.as bait.The content of Zn and Se in the lined seahorse with frozen Mysis spp.as bait was the highest.(4)In terms of overall content,in addition to mineral elements,live bait(live Mysis spp.and Artemia spp.)is superior to frozen bait(frozen Mysis spp.),and live Mysis spp.is the most suitable bait.3.Effects of life stage,gender and pregnancy on biochemical composition of the lined seahorse(H.erectus)In the investigation,the chemical compositions(including cholesterol,amino acids,fatty acids,nucleoside,and mineral elements)of immatured(6-7 cm,sex undifferentiated)and matured(10-11 cm)of H.erectus(including female,non-pregnant and pregnant male)were compared.The results show that(1)the compositions of amino acids and mineral elements were consisitent in the four groups.The minimum content of amino acids was tryptophan,and the highest levels of constant and trace elements were Ca and Zn,respectively.The gender undifferentiated seahorse detected the most nucleosides,and pregnant seahorses detected the least nucleosides,and the two group fatty acids were the most abundant.(2)Among the substances related to aphrodisiac(arginine,n-3 PUFA,cholesterol,adenosine,Zn and Se),the content of n-3 PUFA,Zn and Se in female seahorse was the highest.The content of adenosine,arginine and cholesterol were the highest in male pregnancies seahorse,non-pregnancies seahorse and gender undifferentiated seahorse respectively.(3)Gender,growth stage and pregnancy have a greater impact on the content of biochemical components in hippocampus.In terms of overall content,female lined seahorse is higher than male;male non-pregnant seahorse is higher than pregnant seahorse;sex differentiated seahorse higher than sex undifferentiated seahorse.In the present study,we found that seahorses are Se-and Zn-enriched fishes.The elements collaborate with other bioactive materials may be the fundament functioning as the traditional Chinese medicine,and making them good healthy food as well. |
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