Zhiguo Liufu

Interaction of dietary Bacillus subtilis and fructooligosaccharide on the growth performance, non-specific immunity of sea cucumber, Apostichopus japonicus.

A feeding experiment was conducted to investigate the interaction of probiotic Bacillus subtilis and prebiotic fructooligosaccharide (FOS) on the growth performance, immunity, intestinal microflora and disease resistance of sea cucumber (Apostichopus japonicus). Five hundred and forty individuals (initial body weight: 5.06 +/- 0.10 g, mean +/- S.E) were fed nine practical diets according to a 3 x 3 factorial design: the basal diet as the control diet supplemented with three levels of B. subtilis (0, 1.82 x 10(7) or 4.95 x 10(7) CFU g(-1) diet), crossed with 0, 0.25% or 0.50% FOS. After 8 weeks, three sea cucumbers per tank were sampled for bacterial quantification and immunity determination. Then all the sea cucumbers left were challenged by Vibrio splendidus. The results showed that dietary B. subtilis significantly increased the specific growth rate (SGR), total coelomocytes counts (TCC), phagocytosis of sea cucumbers, the counts of total viable bacteria and disease resistance to V. splendidus (P < 0.05), whereas the counts of Vibrio decreased. However, dietary B. subtilis had no significant effect on phenoloxidase (PO) activity in coelomocyte lysate supernatant (CLS) (P > 0.05). The SGR, PO activity, total viable bacterial counts (TBC) and Vibrio counts (VBC) were significantly affected by dietary FOS. In the group with 0.50% FOS, TCC, phagocytosis and PO activity significantly increased compared to the group fed without FOS in diet (P < 0.05). In the groups with 1.82 x 10(7) CFU B. subtilis/g diet, FOS supplementation remarkably decreased VBC. And higher level of FOS (0.50%) resulted in significantly higher TCC and PO activity compared with 0.25% FOS (P < 0.05). Moreover, the animals fed with diets supplemented with 0.25% and 0.50% FOS at each B. subtilis level had notably lower cumulative mortality after 14 days following V. splendidus exposure (P < 0.05). Under the experimental conditions, dietary B. subtilis and FOS had a synergistic effect on enhancing immunity and disease resistance of sea cucumber (P < 0.05).

Effects of potential probiotic Bacillus subtilis T13 on growth, immunity and disease resistance against Vibrio splendidus infection in juvenile sea cucumber Apostichopus japonicus

A feeding experiment was conducted to determine influences of potential probiotic Bacillus subtilis T13 (isolated from intestine of healthy sea cucumbers) on growth, immunity and disease resistance against Vibrio splendidus infection in juvenile sea cucumbers Apostichopus japonicus. Animals were fed with diets containing B. subtilis T13 at 0, 10(5), 10(7) and 10(9) CFU/g for 30 days, respectively. At the end of the growth trial, fifteen sea cucumbers from each aquarium were sampled for immune indices measurement. Then twenty sea cucumbers from each replicate were challenged with V. splendidus. Results showed that administration of B. subtilis T13 had significant effect on the specific growth rates (SGR) of sea cucumbers (P < 0.05). Phagocytosis, respiratory burst activity and total nitric oxide synthase (T-NOS) activity were significantly improved in coelomocytes of sea cucumbers fed with T13 at 10(9) CFU/g diet (P < 0.05). The highest values of the total coelomocytes counts (TCC) and superoxide dismutase (SOD) activity were found in sea cucumbers fed diet containing T13 at 10(9) CFU/g. The cumulative mortality after V. splendidus challenge decreased significantly in sea cucumbers fed with T13 at dose of 10(9) CFU/g (P < 0.05). The present study confirmed the potential beneficial effects of B. subtilis T13 as dietary probiotic in juvenile A. japonicus.

EFFECTS OF VITAMIN E ON ANTIOXIDANT ENZYME ACTIVITIES AND FATTY ACID COMPOSITIONS IN JUVENILE ABALONE HALIOTIS DISCUS HANNAI INO

Abstract A 240-day feeding trial was conducted in a recirculated water system to investigate the effects of dietary vitamin E on the activities of antioxidant enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidase, GPX) and the composition of fatty acids in abalone, Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 0.71 ± 0.00 g; initial shell length: 15.49 ± 0.04 mm) were fed to satiation one of three semipurified diets containing 0, 50, and 5,000-mg/kg vitamin E, respectively. Abalone were sampled on the 120th day and the 240th day, respectively. There were no significant differences in activities of CAT and SOD in soft body of abalone fed with different levels of dietary vitamin E for 120 days (P > 0.05), but significantly higher activity of GPX was found with 5,000-mg/kg dietary vitamin E (P < 0.05). Activities of CAT and GPX were significantly elevated by dietary vitamin E on the 240th day. The lowest value of 18:1n-9, 18:2n-6 and the highest value of 22:6n-3 in soft body were found with 50 mg/kg dietary vitamin E supplement on the 120th day. On the 240th day, the content of monounsaturated fatty acids (MUFA) in abalone with 50-mg/kg dietary vitamin E supplement was significantly higher than those in the other two treatments (P < 0.05). There were no significant effects of dietary vitamin E on the content of polyunsaturated fatty acids (PUFA) in abalone during the two sampling periods (P > 0.05). In conclusion, 50-mg/kg dietary vitamin E supplement elevated the activities of antioxidant enzymes and could protect MUFA from peroxidation damage. Excessive dietary vitamin E (5,000 mg/kg) did not serve as an antioxidant any more, but tended to be a pro-oxidant in the soft body of abalone.

INTERACTION BETWEEN VITAMINS A AND D ON GROWTH AND METABOLIC RESPONSES OF ABALONE HALIOTIS DISCUS HANNAI, INO

Abstract A 152-day growth experiment was conducted in a recirculated water system to investigate the interaction between vitamins A (retinol) and D (cholecalciferol) on growth and metabolic responses in abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 0.35 ± 0.03 g; initial shell length: 11.31 ± 0.25 mm) were fed to satiation one of 16 semipurified diets containing 0, 1 × 103, 1 × 105, 1 × 106 IU/kg vitamin A and 0, 500, 1 × 103, 5 × 103 IU/kg vitamin D in a 4 ×4 factorial design. Abalone were weighed and shell-length measured on the 76th day and the 152nd day, respectively. The total specific growth rate (SGR) during the 152 days, neither the SGR in the first 76 days nor in the second 76 days, was significantly influenced by the interaction between vitamins A and D. Dietary vitamins A and D significantly stimulated viscera 25-hydroxyvitamin D3 [25(OH)D3] and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] contents in a cooperative fashion. Dietary vitamin A generally increased the alkaline phosphatase (AKP) activity in viscera except the excessive supplement (1 × 106 IU/kg), which significantly decreased AKP activity. Dietary vitamin D significantly increased AKP activity. Contents of P, not Ca and Mg, in soft body increased with dietary vitamin D supplement. Dietary vitamin A significantly improved contents of lipid and retinol in soft body and viscera, respectively. Meanwhile, dietary vitamin D significantly increased contents of ash and cholecalciferol in soft body and viscera, respectively. Based on these results, interaction between vitamins A and D was expressed in various manners as different indicators were considered, though there was potential antagonism mechanism at molecular level between the two fat-soluble vitamins.

Effects of dietary corn gluten meal on growth performance and protein metabolism in relation to IGF-I and TOR gene expression of juvenile cobia (Rachycentron canadum)

A growth experiment was conducted on cobia (Rachycentron canadum, initial weight 108.2 g ± 3.0 g) to investigate the effects of dietary corn gluten meal (CGM) levels on the fish growth, whole body composition and protein metabolism in relation to specific gene expression. Five isonitrogenous (crude protein 45%) and isoenergetic (gross energy 20 kJ g−1) practical diets were formulated by replacing 0% (the control), 17.5%, 35.0%, 52.5%, and 70.0% of fish meal (FM) protein with CGM protein. No significant differences were observed in the survival, feed intake (FI), specific growth rate (SGR), feed efficiency (FE) and protein productive value (PPV) among fish fed diets with 0%, 17.5%, 35.0%, and 52.5% of CGM protein. However, these indices were significantly lower in fish fed the diet with 70.0% of CGM protein than those in fish fed the control diet (P < 0.05). The whole-body crude protein and lipid contents were significantly lower while the whole-body moisture content was significantly higher in fish fed the diet with 70.0% of CGM protein compared with the control group (P < 0.05). When 70.0% of FM protein was replaced by CGM, plasma total protein and cholesterol contents were significantly lower than those in the control group (P < 0.05). Fish fed the diet with 70.0% of CGM protein had significantly lower hepatic insulin-like growth factor I (IGF-I) expression levels than those in the control group (P < 0.05). However, no significant differences were observed in hepatic target of rapamycin (TOR), dorsal muscle IGF-I and TOR expression levels among dietary treatments. Results of the present study indicated that 52.5% of FM protein could be replaced by CGM in the diets without significant influences on the growth, feed utilization and protein metabolism of juvenile cobia. The present results might be useful for developing cost effective and sustainable cobia dietary formulations.

Effects of antinutritional factors on plasma lipoprotein levels in Japanese flounder Paralichthys olivaceus

This study examined the effects of four types of antinutritional factor (phytic acid, stachyose, soy saponins and soy isoflavones) on lipoprotein levels in plasma of Japanese flounder Paralichthys olivaceus. A basal diet was prepared with fish meal as primary protein source, the other diets were supplemented with 0·2, 0·4 or 0·8% phytic acid, 0·4, 0·8 or 1·5% stachyose, 0·1, 0·35 or 0·7% soy saponins and 0·10, 0·35 or 0·70% soy isoflavones, by dry mass, in place of white flour in the basal diet. Total cholesterol (TC) and triglyceride (TG) levels in plasma of P. olivaceus were not affected by phytic acid or stachyose. In general, addition of 0·2-0·8% phytic acid or 0·4-1·5% stachyose decreased plasma high-density lipoprotein cholesterol (HDL-C) levels, increased plasma low-density lipoprotein cholesterol (LDL-C) levels, thereby increasing the LDL-C:HDL-C ratio. By contrast, supplementation with 0·35-0·7% soy saponins generally depressed plasma TC levels and the LDL-C:HDL-C ratio. Supplementation with 0·35-0·7% soy isoflavones, however, increased plasma TC and TG levels. These results indicate that soy saponins may be partly responsible for the cholesterol-lowering effects of soybean meal.

Dietary protein requirement of juvenile turbot (Scophthalmus maximus Linnaeus)

The dietary protein requirement of juvenile turbot (initial average weight, 38.2 g ± 0.1 g) reared indoor in aerated aquaria was determined in this study. Five energy equal experimental diets were formulated with fish meal as protein source, which contained different concentrations of protein (47.2%, 51.0%, 54.6%, 59.3% and 63.6% of dry diet). Three groups of fish with 18 individuals in each, were cultured in 300-L tanks and fed twice a day for 8 weeks. During culture, temperature was controlled between 15.0 and 18.0°C, salinity was controlled between 28.5 and 32.0, acidity was controlled between pH7.8 and pH8.5, and ammonia nitrogen was maintained below 0.03 mg L−1 and dissolved oxygen was maintained about 7 mg L−1. Results showed that the growth of fish was significantly affected by dietary protein content (P < 0.05). Specific growth rate (SGR) of turbot increased when dietary protein content varied between 47.2% and 51.0% (P < 0.05), and then kept stable when dietary protein content was higher than 51.0%. Fish which were fed the diet containing 63.6% protein showed the highest SGR while those fed the diet containing 59.3% protein showed the highest feed efficiency rate. No significant difference of feed intake and protein efficiency ratio was found among experimental diets (P > 0.05). Broken-line regression analysis of SGR showed that the optimal dietary protein requirement of turbot was about 57.0%.

Effect of dietary lipid on the growth, fatty acid composition and Δ5 Fads expression of abalone (Haliotis discus hannai Ino) hepatopancreas

This study investigated the effect of dietary lipid on the growth, fatty acid composition and Δ5 fatty acyl desaturase genes (Fads) expression of juvenile abalone (Haliotis discus hannai Ino) hepatopancreas. Six purified diets were formulated to contain tripalmitin (TP), olive oil (OO, 72.87% 18:1n-9), grape seed oil (GO, 68.67% 18:2n-6), linseed oil (LO, 70.48% 18:3n-3), ARA oil (AO, 41.81% ARA) or EPA oil (EO, 44.09% EPA and 23.67% DAH). No significant difference in survival rate was observed among abalone fed with different diets. Weight gain rate (WGR) and daily growth rate of shell length (DGRSL) were significantly increased in abalone fed with diets containing OO, AO and EO, but decreased in abalone fed with LO diet (P < 0.05) in comparison with those fed with TP. High level of dietary 18:2n-6 resulted in higher content of n-6 polyunsaturated fatty acids (PUFAs) in abalone fed with GO than those fed with TP, OO, LO and EO (P < 0.05). n-3 PUFAs in abalone fed with LO was significantly higher than those in abalone fed with TP, OO, GO and AO (P < 0.05). The highest contents of 20:1n-9 and 22:1n-9 were observed in abalone fed with OO. The expression of Δ5 Fads in hepatopancreas of abalone was enhanced by high concentration of 18:3n-3 and suppressed by dietary LC-PUFAs; however it was not affected by dietary high concentration of 18:1n-9 or 18:2n-6. These results provided valuable information for understanding the synthesis of LC-PUFAs and nutritional regulation of Δ5 Fads expression in abalone.

EFFECTS OF DIETARY POTASSIUM ON GROWTH PERFORMANCE OF JUVENILE ABALONE (HALIOTIS DISCUS HANNAI INO) AND ITS PHYSIOLOGICAL RESPONSES: EFFECTS OF DIETARY POTASSIUM ON GROWTH PERFORMANCE OF JUVENILE ABALONE (HALIOTIS DISCUS HANNAI INO) AND ITS PHYSIOLOGICAL RESPONSES

A 15-week feeding trial was conducted to study the effects of dietary potassium on growth and physiological responses of juvenile abalone,Haliotis discus hannai Ino.Six casein-gelatin based semi-purified diets containing graded levels of dietary potassium(KCl,0.10,2.12,4.39,9.79,20.08 and 27.26 g/kg dry diet,respectively) were fed to juvenile abalone [initial weight:(0.24 ± 0.00) g;initial shell length:(12.24 ± 0.04) mm] in triplicate groups in a flow-through system.During the experimental period,the water temperature ranged from 12 to 23℃ and potassium concentration was(472.94 ± 3.59) mg/L in the seawater.The results showed that there were no significant(P 0.05) differences in the weight gain ratio(WGR,%),daily increment in shell length(DISL,μm/d) and the survival of abalone among treatments.There were also no significant(P 0.05) differences in lipid,moisture contents in soft body and ash content in shell among the six dietary treatments.Compared with that in the treatment of 0.10 g/kg diet,the protein content in soft body increased significantly(P 0.05) when dietary potassium was more than 4.39 g/kg diet.The content of potassium in the soft body and potassium,sodium in the shell was maintained relatively constant regardless of dietary treatment.The soft body sodium content was significantly(P 0.05) lower in 20.08 and 27.26 g/kg of dietary treatment than any other treatments.The activity of gill Na+-K+ ATPase decreased steadily with the increasing of dietary potassium.Data from the growth parameters(WGR and DISL) showed that it was unnecessary to add potassium to the diets,and the potassium from diet sources and seawater was sufficient for the optimal growth of juvenile abalone.Based on the physical index(protein and sodium contents in soft body and Na+-K+ ATPase activity in gill),the optimal concentration of dietary potassium was 2.12 g/kg.

Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.