Researches On Selecting Feedstuff And Dietary Protein Requirement Of Juvenil Apostichopus Japonicus

In recent years, the Apostichopus japonicus aquaculture industry rised and developed rapidly in China, but the research on nutrition and feed science about Apostichopus japonicus was relative behind of the requirement of this aquaculture industry. In this paper, aiming at the shortage of research on nutrition and artificial feed for Apostichopus japonicus, we studied and discussed the selection of suitable feedstuff and dietary protein requirement for juvenil Apostichopus japonicus according to the growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus. Wish that this study could provide theory parameters for the research and development of reasonable nutrition and high economic benefit artificial compound feed in future. The main results were as follows:1. Research on selecting feedstuff of juvenil Apostichopus japonicusThe experiment determined which kind of feedstuff was suitablely used as main component of artificial compound feed for Apostichopus japonicus, according to the studies and analysis about the influence of Laminaria japonica, Degummed Kelp, Alfalfa and Ulva lactuca on the growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus.The results showed that the growth performance of juvenil Apostichopus japonicus fed with diet of Degummed Kelp was best of all (P<0.05), which could meet the nutrition requirement of juvenil Apostichopus japonicus better. The growth performance of Laminaria japonica and Ulva lactuca powder group were equal, and a little better than Alfalfa powder group, but they were not significantly different from each orther (P>0.05). The content of crud protein and fat in body wall of Apostichopus japonicus fed with diet of Ulva lactuca powder was significantly higher than others (P<0.05), the Ulva lactuca powder could contribute to improving the nutrition content of Apostichopus japonicus. The Laminaria japonica powder could improve the length of digestive tract and the activity of amylase and lipase in the digestive tract than others (P<0.05), Conduciving to the digestion and absorption of feed nutrition. In the Degummed Kelp powder group, The activity of GOT in the digestive tract of Apostichopus japonicus was a little higher, and GOT/GPT was highest in four groups, so the amino acid metabolism and protein synthesis were active in the body of Apostichopus japonicus, contributing to the nitrogen deposition in the body. The Laminaria japonica and Degummed Kelp powder could improve the immune function of juvenil Apostichopus japonicus.Take the influence of four kinds of feedstuff on growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus into consideration. It could be seen that the four kinds of raw materials can be effectively utilized by juvenil Apostichopus japonicus, showing a good growth effect. So they can be used in compound feed of Apostichopus japonicus. The Degummed Kelp powder could be used as the main ingredient of diets to meet the nutritional requirement of juvenil Apostichopus japonicus, and could keep higher immune function in the digestive tract of Apostichopus japonicus. The Laminaria japonica, Ulva lactuca and Alfalfa powder could be used as auxiliary ingredient of diets to enrich feed nutrient composition, improve the digestive ability and nutritional value of Apostichopus japonicus, and also could supply more feed resources.2. Researches on dietary protein requirement of juvenil Apostichopus japonicusIn order to obtain more accurate data, the juvenil Apostichopus japonicus were successively fed in the preliminary experiment (CP1) and accurate experiment (CP2) with different dietary protein level experimental diets, which were mainly composed of Degummed Kelp powder and casein. And the dietary protein level of CP1experimental diets was15.55%、18.08%、20.47%、22.72%、25.25%、27.79%, the dietary protein level of CP2experimental diets was16.82%、17.91%、18.90%、19.87%、20.99%. We have studied and ascertained the dietary protein requirement of juvenil Apostichopus japonicus by means of analysing the effects of dietary protein level on the growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus.The results showed that with the increase of dietary protein, the weight growth rate, specific growth rate, feed conversion rate and protein efficiency ratio increased significantly firstly, and then decreased. The growth performance of Apostichopus japonicus were better than others when the dietary protein level was18.08%～20.47%in the experiment of CP1. A better growth effect was got when the dietary protein level was18.90%～19.87%in the experiment of CP2, reached best at19.44%dietary protein level, and was within the experimental result of CP1.The content of crud protein in body wall increased gradually, and the content of crud fat decreased with the dietary protein level improvement, but the content of moisture and crude ash in body wall were not influenced by dietary protein level (P>0.05). The activity of stomach protease in the foregut and midgut increased significantly firstly, then decreased, and respectively reached maximum at20.47%and18.08%protein level diet, the activity of amylase raised gradually(P<0.05), and the activity of lipase in foregut raised gradually(P>0.05), but the activity of lipase in midgut changed not obviously. The activity of GOT in digestive tract increased significantly firstly, then decreased, and reached maximum at20.47%, The activity of GPT in digestive tract increased gradually, but the variation tendency of GOT/GPT was the same as GOT, reached maximum at20.47%. When the dietary protein level was nearby comfort zone of18.08%, the activity of SOD、CAT、LZM and ACP in the digestive tract was higher level, appeared stronger immunity.Take the effects of different dietary protein level on growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus into consideration. It could be seen that when the dietary protein level was nearby comfort zone of18.90%～19.87%, the growth performance, digestive physiological characteristics and immune function of juvenil Apostichopus japonicus was higher level, reached best at19.44%dietary protein level.