The aim of the present study was to explore the effects of four kinds of non-nutritive additives on the activity of digestive enzymes, immune function and in vitro digestibility of liver and pancreas of Australian freshwater lobster (Cherax quadricarinatus), and to screen out the appropriate feed additives, so as to provide a theoretical basis for the application and research of non-nutritive additives in feed. Citric acid (S-Ⅰ), complex enzyme preparation (S-Ⅱ), Lactobacillus plantarum plus Bacillus subtilis (S-Ⅲ), and rhizobium plus B.subtilis (S-IV) were used as the non-nutritive additives to feed Australian freshwater lobster for 14 days. Then, activities of enzymes [alkaline phosphatase(AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC)] as well as in vitro digestibility of feed (dry matter digestibility, protein digestibility and amino acid production rate) were detected. S-Ⅰ could significantly increase (P<0.05) the activities of amylase, AKP and SOD in the hepatopancreas of Australian freshwater lobster, and S-Ⅱ could significantly increase (P<0.05) the activities of amylase, trypsin and immune function. The digestive enzyme and immune function of S-Ⅲ and S-Ⅳ were significantly improved (P<0.05). Among the four non-nutritive feed additives, S-IV had the highest dry matter digestibility, protein digestibility and amino acid production rate in vitro. The digestive enzyme activity, immune function and in vitro digestibility of S-Ⅲ and S-Ⅳ were higher than those of S-Ⅰ or S-Ⅱ, and in vitro digestibility of S-Ⅳ was higher than that of S-Ⅲ, so S-Ⅳ was preferred among the four non-nutritive additives.

Methods of cleaning the fouling organisms in the process of aquaculture is related to production benefit, because of the aquaculture facilities, mariculture objects or aquaculture process can be affected by fouling organisms.The present paper investigated the treatment methods for fouling organisms of marine aquaculture facilities in the main aquaculture areas of Fujian Province.According to the survey, there was a lack of effective preventive measures while manual removal was the main way.Actually, the fish farmers usually ignored it, even if needed to clean, dry or manual removal were the preferred methods.Only a few were treated with a screen washer or sprayed with formalin.The survey showed that the main treatment methods for fouling organisms in Fujian province were traditional, time-consuming, inefficient, and labor intensive, even more, advanced technique and equipment were difficult to adapt to actual production.

The best extracting process of gelatin from ballomfish skin was studied. To observe the effect of sodium hydroxide and vitriol and their action time to the extracting efficiency and quality.The results showed that the ballomfish skin was marinate with 8 times volume of 0.2%sodium hydroxide and 0.3%vitriol successively. Then the factors of the volume of water, the time and the temperature of extracting to the influence of the extracting rate were observed. The results showed that the best extracting technology was 4 times volume,the temperature was 60℃,and two hours one time.