| In this study,iron cage culture technology was used to compare the cultivation traits,nutritional components and the effects of Bostrychus sinensis on the physical and chemical properties of basal soil in two species of mangrove and flats.The Bostrychus sinensis who's average body weight was(10.50±2.55)g was selected as the seedling.A total of 4 experimental groups were set up as follows:(1)the group of unfed in mudflat,(2)the group of feeding in mudflat,(3)the group of unfed under mangroves,(4)the group of feeding under mangroves.Each experimental group was designed three parallel repetitions.The eel fish meal and the NO.0 prawn feed were mixed with 3:1 to form a sticky food as feed.The specifications of the cage are(length x width x height)1m x 0.4 m x 0.8 m.The stocking density was 10/0.4 m~2.The period of culture is 60 days.At the end of the experiment,the experimental fish survived in the cage were counted,the body weight and body length were measured,and the nutritive composition of the muscles was analyzed.The physical and chemical properties of the ground base soil were analyzed before and after the culture.The main results were as follows:1.Beeding traits:The survival rate of the group of feeding under mangroves and the group of feeding in mudflat was 35%,the survival rate of the group of unfed under mangroves was 32.5%,the survival rate of the group of unfed in mudflat was 22.5%.The weight gain rate of the feeding group under mangroves was 55.82%which higher than the feeding group in mudflat(10.17%),and the weight gain rate of the unfed group under mangroves was 20.81%which higher than the unfed group in mudflat(1.65%).The growth rate of the body length of the feeding group under mangroves was 26.34%which higher than the feeding group in mudflat(17.91%),the growth rate of the body length of the unfed group under mangroves was 22.21%which higher than the unfed group in mudflat(10.24%).The specific growth rate of the feeding group under mangroves was 0.74%/t which higher than the feeding group in mudflat(0.16%/t),the specific growth rate of the unfed group under mangroves was 0.31%/t which higher than the unfed group in mudflat(0.03%/t).On the condition factor,the feeding group under mangroves(1.31 g/cm3)>the feeding group in mudflat(1.28 g/cm3)>the unfed group under mangroves(1.12 g/cm3)>the unfed group in mudflat(0.87 g/cm3).2.Muscle nutrient:The crude protein content of all the experimental groups was higher(74.65%-86.15%),the crude fat content was lower(0.89%-1.63%),which belonged to high protein and low fat fish,and the crude protein and crude fat content of the two experimental groups in the mangrove group were higher than that of the two groups of experimental fish cultured in the mudflat.The total amount of amino acid(71.72%-84.52%),total amino acid(29.03%-32.57%),total essential amino acid(27.47%-34.14%)and total amount of non essential amino acids(44.25%-50.37%)were the highest in pond culture fish,and the lowest in the group of unfed in mudflat,and the two groups of cultured under the mangroves were higher than the two groups of cultured in the mudflat.The essential amino acid index EAAI of the experimental fish muscles was higher in 66.83-79.96.The limiting amino acids were valine,isoleucine and(methionine+cystine),and the F value was higher in 2.17-2.24.The muscle protein was basically in line with the ideal protein requirements recommended by FAO/WHO,and had certain health function.The muscles of all the experimental fish were rich in unsaturated fatty acids,and polyunsaturated fatty acids were the major.The content of polyunsaturated fatty acids and(EPA+DHA)content in the two groups of experimental fish muscles which cultured under mangroves were higher than those of two groups of experimental fish cultured in the mudflat.3.Physicochemical properties of soil:The effect of artificial cage on the total organic matter,total nitrogen and total phosphorus in the basal soil under mangrove forest was influenced by the bait group,which had little influence on the pH value and salinity.To sum up,the Bostrychus sinensis which cultured under the mangroves has certain advantages inbreeding traits and nutrients compared with cultured in mudflat.The Bostrychus sinensis muscle which cultured under the mangroves is much more delicious than which cultured in mudflat,and has higher nutritional value and higher economic benefits.The research results can promote settlement of the contradiction between the protection of mangroves and the local fishermen uses the beach.It is of great significance to the protection of mangroves and the production of the fishermen's production. |
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