中华鳖俗称甲鱼,自20世纪90年代以来,甲鱼人工养殖得到快速发展,主要养殖品系包括台湾鳖、泰国鳖、日本鳖、黄河鳖和黄沙鳖等.根据不完全统计,10余年间甲鱼产量增长了将近10倍.然而,在产量激增的背后,是产业发展的严重失序.养殖业严重过剩,大量甲鱼滞销,其中温室甲鱼有40％左右,外塘甲鱼有20％～30％,未来可能将有20％甲鱼养殖户遭淘汰,不利于甲鱼养殖产业的稳定.此外,病害和养殖过程中的污染也成为制约甲鱼今后发展的严重瓶颈.

Juvenile abalone, Haliotis discus hannai Ino. of 0.55 +/- 0.02 g in body weight. and 15.48 +/- 0.31 mm in shell length, were fed with six purified diets containing 0, 9.8. 19.8, 39.7, 79.4. 158.5 in,, Ca-pantothenic acid/kg diet for 16 wk. The Ca-pantothenic acid was microbound with sodium alginate. and other water-soluble vitamins were encapsulated with sodium alginate, by an emulsion coacervation process, prior to supplementation in experimental diets. The dietary Ca-pantothenic acid concentration did not affect the body composition of abalone. Weight gain (WG), daily increment in shell length (DISL), and tissue pantothenic acid were significantly affected by dietary pantothenic acid. According to broken-line regression analysis, 21 mg Ca-pantothenic acid/kg diet was found to satisfy the maximum growth of abalone. whereas on the basis of the pantothenic acid concentration in the viscera and muscle of the experimental abalone, 24 and 26 mg Ca-pantothenic acid/kg diet were required, respectively. Hence, the optimum dietary Ca-pantothenic acid requirement for H. discus hannai Ino is estimated to be 26 mg/kg diet.

The experiment was conducted to quantify the biotin requirement of juvenile abalone, Haliotis discus hannai Ino. The possible biotin-synthesizing capacity of: intestinal microflora was also examined. Seven purified dicis were formulated to provide a series of biotin (0, 0.5, 1.0. 3.0, 6.0, 12.0, 20.0 mg/kg diet). An antibiotic diet was Supplemented with tretracycline hydrochloride (4-g/kg diet) in basal diet to suppress possible intestinal bacteria synthesis. To reduce leaching. dietary biotin and other water-soluble vitamins were encapsulated by calcium alginate. Abalone juveniles of similar size (initial mean weight 175.1 +/- 3.6 mg mean shell length 11.66 +/- 0.14 mm) were distributed in a flowing-through system using it completely randomized design with eight treatments and three replicates per treatment. They were fed the appropriate diet once every day for a 110-day period. Results of this Study clearly showed the necessity of dietary biotin for juvenile abalone as the daily increment in shell length (DISL). visceral pyruvate carboxylase and acetyl-CoA carboxylase activities were significantly influenced by the dietary biotin levels (ANOVA, P < 0.05). However. the survival, specific growth rate (SGR) and carcass proximate compositions were not significantly influenced by dietary biotin at the end of the experimental period. The viscera biotin concentration (VBC) of abalone increased as the biotin supplementation level increased (r = 0.91). Compared to those of other groups, SGR, DISL, VBC and two carboxylase activities of antibiotic group were obviously depressed. It indicated that the intestinal microflora probably contribute to biotin nutrition for juvenile abalone. Based on measurements of DISL and two carboxylase activities, the optimum biotin requirement was estimated to be 0.42 mg/kg and 0.67-0.70 mg/kg for maximum growth and carboxylase activities, respectively.

Juvenile abalone, Haliotis discus hannai Ino, of initial weight 0.55±0.02 g, were fed with experimental diets with graded levels of thiamin–HCl (0, 9.8, 18.9, 37.2, 75.9, 150.4 and 309.5 mg/kg diet) for 16 weeks. Thiamin–HCl and other water-soluble vitamins were microencapsulated with sodium alginate by an emulsion coacervation process prior to supplementation. To estimate the thiamin requirement of abalone and to evaluate the thiamin status in this animal, weight gain (WG), daily increment in shell length (DISL), tissue thiamin, thiamin pyrophosphate (TPP), thiamin monophosphate (TMP), transketolase (TKA) and thiamin pyrophosphate effect (TPP-effect) both in viscera and muscle were measured. Except for TMP, all parameters mentioned above responded significantly to the change of dietary thiamin levels in a broken line model. However, growth (WG and DISL), TPP concentrations and TPP-effect both in viscera and muscle were found to be the most sensitive indicators. Based on broken line analyses, the thiamin requirement to satisfy maximum growth was estimated to be 51 mg/kg diet, and the dietary thiamin levels to maximize visceral TPP content and TPP-effect of H. discus hannai were estimated to be 61 and 58 mg/kg diet, respectively.

With an aim to reduce leaching of water-soluble vitamins, the leaching properties of five kinds of microparticulate forms of vitamin B1 are investigated by means of dynamic system. These microparticles include: alginate and alginate-CMC microcapsules prepared by emulsion coacervation process (ECP), alginate and gelatin microcapsules prepared by spray-drying process (SDP), and alginate microbound. The results show these five microparticulate forms of VB1 can reduce leaching significantly compared to crystalline form VB1, and the leaching rates at different intervals, diameters and encapsulation efficiencies (EE) are significantly different among all kinds of microparticles (ANOVA, P<0.05). The leaching properties of the five microparticles are in accord with Higuchi equation. Based on the regression equation, the half loss time (T50) is determined.In conclusion, the alginate-CMC microencapsule is a potential tool to reduce leaching of water-soluble vitamins.

The experiments were conducted to investigate the effects of dietary myo-inositol on the survival, growth, proximate composition and de novo synthesis of myo-inositol in abalone, Haliotis discus hannai Ino. The possible inositol-synthesizing capacity of intestinal microflora was also examined. Seven semipurified diets were formulated to provide graded levels of myo-inositol (28.7-1020.1 mg/kg diet). A control diet, the basal diet supplemented with 4 g/kg tetracycline hydrochloride, was employed to suppress synthesis of myo-inositol by intestinal bacteria. Abalone juveniles of similar size (weight, 144.6 +/- 0.8 mg; shell length, 10.92 +/- 0.10 mm) were distributed in a flow-through system using a completely randomized design with eight treatments and three replicates per treatment. They were fed the appropriate diets once daily for 16 wk. Survival, growth, crude protein, lipid, moisture of whole soft body and visceral inositol content were independent of myo-inositol supplementation (P > 0.05). The addition of the antibiotic also did not affect the survival, growth and whole soft body composition. It indicated that intestinal microflora contributed little to the myo-inositol nutrition in abalone. The present study, for the first time, demonstrated de novo synthesis of myo-inositol in mollusks because the visceral tissue of abalone showed high levels of myo-inositol synthetase activities (combined activities of myo-inositol-1-phosphate synthetase and inositol-1-phosphatase), ranging from 74.0 to 98.2 micromol/(h x g protein). The enzyme activity significantly and negatively correlated with dietary myo-inositol level (r = -0.81). Hence, dietary myo-inositol is not essential for abalone because tissue synthesis of the vitamin appears to be sufficient to support normal growth and health of this mollusk.

The experiments were conducted to investigate the effects of dietary myo-inositol on the survival, growth, proximate composition and de novo synthesis of myo-inositol in abalone, Haliotis discus hannai Ino. The possible inositol-synthesizing capacity of intestinal microflora was also examined. Seven semipurified diets were formulated to provide graded levels of myo-inositol (28.7–1020.1 mg/kg diet). A control diet, the basal diet supplemented with 4 g/kg tetracycline hydrochloride, was employed to suppress synthesis of myo-inositol by intestinal bacteria. Abalone juveniles of similar size (weight, 144.6 6 0.8 mg; shell length, 10.92 6 0.10 mm) were distributed in a flow-through system using a completely randomized design with eight treatments and three replicates per treatment. They were fed the appropriate diets once daily for 16 wk. Survival, growth, crude protein, lipid, moisture of whole soft body and visceral inositol content were independent of myo-inositol supplementation (P . 0.05). The addition of the antibiotic also did not affect the survival, growth and whole soft body composition. It indicated that intestinal microflora contributed little to the myo-inositol nutrition in abalone. The present study, for the first time, demonstrated de novo synthesis of myo-inositol in mollusks because the visceral tissue of abalone showed high levels of myo-inositol synthetase activities (combined activities of myo-inositol-1-phosphate synthetase and inositol-1-phosphatase), ranging from 74.0 to 98.2 mmol/(hzg protein). The enzyme activity significantly and negatively correlated with dietary myo-inositol level (r 5 20.81). Hence, dietary myo-inositol is not essential for abalone because tissue synthesis of the vitamin appears to be sufficient to support normal growth and health of this mollusk. J. Nutr. 131: 2898–2903, 2001.