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1.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

2.
A series of laboratory experiments were conducted on the harpacticoid copepod, Euterpina acutifrons, to assess the influence of 10 different microalgal diets (four monoalgal and six mixed algal diets) on several parameters related to its productivity in culture. The four monoalgal diets were the Tahitian strain of Isochrysis sp. (T‐Iso), Pavlova salina (Pav), Tetraselmis chuii (Tet) and the diatom Chaetoceros muelleri (Chaet), the five binary diets were T‐Iso+Tet, Pav+Tet, T‐Iso+Pav, Tet+Chaet and Pav+Chaet, while the tri‐algal diet was T‐Iso+Tet+Pav. All diets were fed to copepods at 1500 μ gC L?1 and in the case of binary or trialgal diets, carbon concentration was divided equally between the two or three algae offered. Among monoalgal diets, the diatom Chaet was excellent for E. acutifrons. Out of the 10 diets tested, the binary diet Tet+Chaet, which contained the diatom Chaet, was the best for naupliar production of single pair E. acutifrons (19.5±1.7 nauplii female?1 day?1), significantly (P<0.05) higher than all other treatments except for the Chaet treatment (P>0.05). Similarly, in the group naupliar production trial (50 adult E. acutifrons per replicate), Tet+Chaet produced a significantly higher number of nauplii (405.8±18.6 nauplii day?1) than the other treatments (P<0.05). Tet+Chaet further supported the highest naupliar survival (82.0±2.8%) and copepodite survival (89.0±2.8%), while the mono‐algal diet Chaet produced the second highest naupliar (76.7±2.6%) and copepodite survival (83.5±2.6%). In contrast, Pav produced the lowest overall survival at the naupliar stage (30.0±2.9%), significantly lower than all other treatments (P<0.05). While development from newly hatched nauplii to copepodites was not significantly affected by diets, mean development time from nauplius to adult was significantly different among treatments. Mean development time from hatching (naupliar I stage; NI) to the adult stage was the fastest with Tet+Chaet and Chaet (6.8±0.0 days for both treatments), which was significantly faster than that of Pav, T‐Iso Pav+Tet and T‐Iso+Pav+Te treatment (P<0.05). E. acutifrons sex ratio was significantly affected by diets, and always skewed in favour of males. Feeding on Pav resulted in the lowest proportion of females (23.7±1.2%), significantly lower than for six of the other treatments (P<0.05). Adult females had longer average life expectancy than males for all treatments, and were the longest when fed Tet+Chaet (9.5±0.4 days), which was more than twice as long as the shortest lifespan recorded for the Pav treatment (4.2±0.6 days) (P<0.05). In summary, among 10 diets tested, the binary diet Tet+Chaet appeared to support the highest culture productivity of E. acutifrons while the diatom Chaet also performed well as a monoalgal diet.  相似文献   

3.
We examined the effects of 10 microalgal diets on a range of productivity‐related parameters of Bestiolina similis. The diets tested included four monoalgal diets: Tahitian strain Isochrysis sp. (T‐Iso), Pavlova salina (Pav), Tetraselmis chuii (Tet) and the diatom Chaetoceros muelleri (Chaet), five binary diets: Tet+Pav, T‐Iso+Tet, T‐Iso+Pav, Chaet+Tet and Chaet+Pav and a tri‐algal diet: T‐Iso+Tet+Pav. Except for sex ratio, microalgal diets significantly affected all parameters examined (P<0.05). The shortest egg incubation time was found for the tri‐algal diet treatment (1.91±0.04 days) while the longest (2.41±0.09 days) was from the monoalgal diet Tet. Survival at the naupliar stage ranged from the highest of 86.3±1.0% for the tri‐algal diet to a complete mortality for the Tet diet. Naupliar survival was consistently higher than that of copepodite stages for all diets examined and ranged from 86.3±1.0% for the tri‐algal diet to a complete mortality for the Tet diet. Copepodite survival was the highest for the T‐Iso treatment (69.0±4.3%) while Chaet+Tet produced the lowest survival (8.8±1.2%). Sex ratio of B. similis was strongly skewed towards females. Adult female life expectancy was highly dependent on diet. The shortest lifespan (3.1±0.3 days) of the Tet treatment was only about half of that of Pav (6.3±0.6 days) and the tri‐algal diet (5.9±0.4 days). Daily egg production during female lifespan was generally lower on the first day, but peaked over the subsequent days before decreasing towards the end of their lifespan. The highest total egg output over female lifespan was produced by the tri‐algal diet (156.0±11.5 eggs female?1), while the lowest output came from the diet Tet (20.7±2.8 eggs female?1).  相似文献   

4.
Dietary enrichments with the arachidonic acid (ARA)‐rich microalga, Parietochloris incisa, on the survival of guppy (Poecilia reticulata) fry were examined. Diets were applied via Artemia enrichment to fish from two commercial farms for 34 and 36 days of experimental period (trials 1 and 2, respectively). In trial 1, Artemia nauplii were enriched with dry biomass of whole algal cells at 0 (control), 0.1, 0.2 and 0.4 mg mL?1. Fry fed with Artemia enriched with 0.4 mg mL?1 demonstrated the lowest mortality rates (24% and 1% in farms 1 and 2, respectively) compared with controls (36% and 13% in farms 1 and 2, respectively). In trial 2, fry were fed with Artemia, enriched with whole algal cells (0.4 mg ml?1), algal hexane extract (HE; containing primarily ARA‐rich triacylglycerols and β‐carotene; 0.19 mg ml?1) or the extraction residue (0.28 mg ml?1). Acute stress (5 min air exposure) was applied after 18 days. The lowest mortality was recorded in the whole alga‐fed group (av. 26% and 2.6% in farms 1 and 2, respectively), with a slightly, but not significantly higher mortality in the HE‐fed group (av. 29% and 6.2% in farms 1 and 2, respectively). Elevated lysozyme was associated with the reduced mortality. Overall, the use of P. incisa as a dietary supplement for guppy fry during their first month of life enhanced their survival and stress resistance.  相似文献   

5.
Two trials were conducted to evaluate the growth, survival and hepatopancreas histology of the Argentine red shrimp Pleoticus muelleri (Bate, 1888) fed different levels of vitamin E and butylated hydroxytoluene (BHT) in a semipurified diet. The diets contained 0, 100, 600 or 1500 mg vitamin E kg?1 and 16 mg BHT kg?1 diet (trial 1) and 0, 1250, 1500, 1750 or 2000 mg vitamin E kg?1 diet, squid mantle and vitamin‐free diet as a control (trial 2). After 30 days (trial 1), survival ranged between 43% and 64%, and the percentage weight gain of the shrimp varied from 22% to 31% with no significant differences among treatments (P<0.05). After 40 days (trial 2), survival of shrimp fed the diet with no vitamin E and squid mantle was significantly lower (62%) than the other treatment (86–90%). Shrimp fed diets containing vitamin E from 1250 to 1750 mg kg?1 exhibited increased weight gain (34–65%); however, a significant difference was observed for shrimp fed the diet containing 2000 mg kg?1. Histological results yielded differences among treatments. In shrimp fed 1750 mg kg?1 of vitamin E, the functional morphology of the organ was normal, with abundant secretion in the tubules. Signs of malnourishment such as cellular and nuclear retraction, desquamation of cells and hipertrofia, were evident in the hepatopancreas of shrimp fed the other diets. The results indicate that optimal vitamin E requirement for P. muelleri under the present experimental conditions appears to be approximately 1750 mg vitamin E kg?1 diet.  相似文献   

6.
A feeding experiment was conducted to investigate the effects of high dietary intake of vitamin E (supplied as dl ‐α‐tocopheryl acetate) and n‐3 highly unsaturated fatty acid (n‐3 HUFA) on the non‐specific immune response and disease resistance in Japanese flounder Paralichthys olivaceus. Nine practical diets were formulated to contain one of three levels of vitamin E namely, 0, 80 or 200 mg kg?1 (the total α‐tocopherol contents in the diets were 21, 97 and 213 mg kg?1 based on analysis), and at each vitamin E level with one of three n‐3 HUFA levels i.e. 0.5%, 1.5% or 2.0%. Each diet was randomly assigned to triplicate groups of Japanese flounder (initial body weight: 40.5±1.0 g, mean±SD) in a re‐circulation rearing system. Fish were fed twice daily to apparent satiation at 07:00 and 18:00 hours for 12 weeks. During the experimental period, water temperature was maintained at 18±1°C, salinity 31–35 g L?1, and pH 7.8–8.2. Dissolved oxygen was not less than 6 mg L?1, and there were negligible levels of free ammonia and nitrite. The results showed that the increase in dietary n‐3 HUFA from 0.5% to 1.0% significantly decreased muscle α‐tocopherol contents in fish‐fed diets with 21 and 97 mg α‐tocopherol kg?1 diet (P<0.05). In 1.0% HUFA groups, alternative complement pathway activity (ACH50) of fish fed the diet containing the 213 mg α‐tocopherol kg?1 diet was significantly higher than noted for fish fed the diet containing 97 mg α‐tocopherol kg?1 diet (P<0.05). Fish fed the diet with 213 mg α‐tocopherol kg?1 and 2.0% n‐3 HUFA had the highest lysozyme activity (131.7 U mL?1) among all the dietary treatments. Fish fed the diets containing 97 and 213 mg α‐tocopherol kg?1 with 1.0% n‐3 HUFA had significantly higher respiratory burst activity than those fed the diets containing 21 mg α‐tocopherol kg?1 with 0.5 and 1.0% n‐3 HUFA (P<0.05). In the disease resistance experiment, high intake of dietary vitamin E with 213 mg α‐tocopherol kg?1 significantly decreased cumulative mortality and delayed the days to first mortality after a 7‐day Edwardsiella tarda challenge (P<0.05). In addition, under the experimental conditions, dietary vitamin E and n‐3 HUFA had a synergistic effect on the non‐specific immune responses and disease resistance in Japanese flounder (P<0.05).  相似文献   

7.
The effects of feeding guppy fry, Poecilia reticulata (Peters), different commercial diets from BernAqua [MeM (R = Regular, O = Ornamental and P = Premium) and experimental feed (EF] and Ocean Nutrition (ON) on growth was tested for 57 days. Health status and resistance to Tetrahymena infection were analysed at the end of the trial. The highest growth was obtained in fish fed MeM Regular and MeM Premium (mean final weights of 427 and 417 mg respectively). Fish fed EF had a significantly higher rate of spinal deformity (12.7%) than all other feeding groups (3.05% or less). Histological analysis revealed the accumulation of liver glycogen and/or lipid in fish from all feeding groups; fat accumulation in the abdomen was most pronounced in the EF and MeM Regular‐fed fish, and muscle dystrophy was observed in ca. 50% of the fish from all feeding groups except the MeM Ornamental‐fed group. The highest mortality following Tetrahymena infection occurred in fish fed EF (87%) and the lowest mortality in the MeM Ornamental‐fed fish (58%). Mortalities in all other feeding groups ranged between 69% and 76%. In summary, MeM Ornamental feed provided a moderate weight gain, no muscle dystrophy, negligible deformity and the greatest resistance to parasitic infection.  相似文献   

8.
As guppies are one of the commercially important fish in freshwater ornamental aquaculture industry, it is important to gain an understanding of guppy immune response for infectious disease control. Till now, the number of study that examined the immune response of guppies is limited and effective tools for monitoring guppy antibody have not been reported. In this study, we successfully isolated guppy IgM using mannan-binding protein (MBP) affinity chromatography and produced specific polyclonal antibodies against guppy IgM heavy and light chains, that showed a molecular weight of approximately 74 and 23 kDa respectively. The produced polyclonal antibodies were used to develop an enzyme-linked immunosorbent assay (ELISA) and have demonstrated to be an effective tool for the detection and quantification of antigen-specific antibody of guppies immunized with Pseudomonas fluorescens. In conclusion, the produced anti-guppy IgM polyclonal antibodies should prove its future implications for immunology and epidemiology studies in guppies.  相似文献   

9.
A feeding trial was conducted to determine the effect of dietary vitamin E supplementation on growth, liver lipid peroxidation and liver and muscle vitamin E level of soft‐shelled turtle, Pelodiscus sinensis. Eight experimental diets analysed to contain 0–457 IU vitamin E kg?1 were fed to juvenile soft‐shelled turtle of 4.8 g initial body weight for 12 weeks. Weight gain (WG) of the turtles fed the diet containing no vitamin E was significantly lower than those fed diets containing 83–457 IU vitamin E kg?1 (P<0.05). Feed conversion ratio and protein efficiency ratio showed similar trends to that of WG. No significant difference (P>0.05) was found in whole‐body composition among turtles fed the different diets. Dietary vitamin E requirement using WG as the response and estimated using the broken‐line regression model is approximately 88 IU kg?1. Liver and muscle vitamin E content increased when dietary vitamin E level increased. Ascorbate‐induced lipid peroxidation in liver tissue of turtles fed diets containing 0 and 17 IU vitamin E kg?1 was significantly (P<0.05) greater than those fed diets containing high vitamin E (≥35 IU kg?1).  相似文献   

10.
The aim of this study was to examine the effects of the immunostimulant combination (IC) containing β‐glucan, A3α‐peptidoglycan, vitamin C and vitamin E on the growth performance, non‐specific immunity and protection against Vibrio harveyi infection in cobia (Rachycentron canadum). Fish were fed diets containing six graded levels of IC (0, 1, 2, 3, 4 and 5 g kg?1 diet) for 8 weeks. The results showed that the survival rate ranged from 81.1 to 84.4% with no significant difference among all the groups (P > 0.05) after the feeding experiment. Dietary IC significantly increased the specific growth rate (SGR), serum lysozyme, alternative complement pathway (ACH50) activity, phagocytosis percentage (PP) and respiratory burst activity of head kidney macrophages of cobia. Moreover, feeding of supplemented diets containing 3.0 g kg?1 IC resulted in significantly lower mortality against the pathogens, V. harveyi compared with the control group. To elevate the growth and immune resistance ability of cobia, the optimal dose of dietary IC administration, determined by second‐order polynomial regression analysis was 3.43 and 2.71 g kg?1 diet, respectively, on the basis of the SGR and mortality after challenge with V. harveyi.  相似文献   

11.
Juvenile barramundi (～220–280 g start weight) were fed extruded dry‐pelleted diets containing varying amounts of fish meal and meat meal in three experiments (E). E1 and E2 were each 66‐day farm studies utilizing 16 floating cages (400 fish per cage) in an aerated freshwater pond. E3 examined the same diets as fed in E2 but under controlled water temperature (28 ± 0.7 °C) and photoperiod (12:12) laboratory conditions in a 42‐day study involving 24 aquaria (eight fish per aquarium). In all studies, the same 430 g kg?1 crude protein (CP), 15 kJ g?1 digestible energy (DE) control (Ctl) diet (containing 35% Chilean anchovy fish meal) was compared with two high‐inclusion meat meal diets and a proprietary diet. The meat meal diets evaluated in E1 were a high‐ash (260 g kg?1) meat meal that contained 520 g kg?1 CP and a low‐ash (140 g kg?1) meat meal that contained 600 g kg?1 CP when included at either 450 or 400 g kg?1, respectively, in combination with 100 g kg?1 Chilean fish meal in diets that were isonitrogenous and isoenergetic with the Ctl diet. Growth rates and feed conversions were similar (P > 0.05) for all diets. In E2 and E3, the 520 g kg?1 CP meat meal was included at 500 g kg?1 without any marine protein source in diets formulated to provide either 15 or 16.2 kJ g?1 DE and the same CP/DE ratio (29 mg kJ?1) as the Ctl diet. Fish performance ranking of diets was similar in both experiments, with the 16.2 kJ g?1 DE diet supporting better (P < 0.05) growth rates than the Ctl diet and feed conversion ratios equivalent to the Ctl diet but better (P < 0.05) than all other diets.  相似文献   

12.
A feeding trial was conducted for 60 days to delineate the effect of both gelatinized and non‐gelatinized corn with or without supplementation of exogenous α‐amylase at two level of protein 35% (optimum) and 27% (sub‐optimum) on growth, tissue composition and protein sparing effect of carbohydrate in the diet of Labeo rohita fingerlings. Three hundred and sixty fingerlings (average weight 10.00±0.15 g) were randomly distributed in 12 treatment groups with two replicates for each. Twelve semi‐purified diets containing either 35% or 27% CP were prepared with different levels of α‐amylase (0, 50, 100 and 150 mg kg?1) and starch type [gelatinized (G)/non‐gelatinized, (NG)] viz. T1 (NG, 35% CP, 0 mg kg?1α‐amylase), T2 (G, 35% CP, 0 mg kg?1α‐amylase), T3 (NG, 27% CP, 50 mg kg?1α‐amylase), T4 (NG, 35% CP, 50 mg kg?1α‐amylase), T5 (G, 27% CP, 50 mg kg?1α‐amylase), T6 (G, 35% CP, 50 mg kg?1α‐amylase), T7 (NG, 27% CP, 100 mg kg?1α‐amylase), T8 (NG, 35% CP, 100 mg kg?1α‐amylase), T9 (G, 27% CP, 100 mg kg?1α‐amylase), T10 (G, 35% CP, 100 mg kg?1α‐amylase), T11 (NG, 27% CP, 150 mg kg?1α‐amylase) and T12 (NG, 35% CP, 150 mg kg?1α‐amylase). The fish were acclimatized to the experimental condition for 24 days during which control diet (NG, 35% CP) was fed. Weight gain percentage, specific growth rate, protein efficiency ratio and apparent net protein utilization of NG corn‐fed groups at 42.43% were significantly higher (P<0.05) than the same level of G corn‐fed groups. We conclude that 42.43% NG corn supplemented with 50 mg α‐amylase kg?1 feed at sub‐optimum level of CP (27%) significantly enhanced the growth and protein in L. rohita fingerling. Addition of dietary α‐amylase to G corn had no added advantage on growth of L. rohita fingerling.  相似文献   

13.
Two feeding trials were carried out to evaluate the efficiency of probiotics and maslinic acid, on growth and survival of juvenile dentex; liver proteolytic activities were also investigated in the second trial. For experiment 1, triplicate groups were fed six diets with two probiotics (Bacillus toyoi, T, and B. cereus, E) at increasing levels (0.5, 1 and 2 g kg?1 diet) and a control diet. Growth and feed conversion were not significantly influenced by the probiotics. The diet T1 produced the lower mortality, whereas diet E1 rendered the higher mortality. It was concluded that no significant effects on growth and survival were found following the addition of two kinds of probiotics to dentex diets. However, the diet E0.5 showed a tendency to ameliorate the growth and feed utilization of the diet. In a second trial, triplicate groups were fed four diets with increasing levels of maslinic acid (0, 20, 40 and 80 mg kg?1 diet). Growth of fish given diets with the highest level of maslinic acid (D80) was slightly but not significantly lower than those from the other groups. Furthemore, mortality of fish fed diet D40 was the lowest. Changes in liver proteasome and endoprotease activities measured on sodium dodecyl sulphate (SDS)/gelatin gels were also detected in a dose‐dependent manner. It was concluded that a dietary maslinic acid at a level of 80 mg kg?1 diet seems to be too high for juvenile dentex to maintain a maximal growth and survival rate.  相似文献   

14.
Toxicity of aflatoxin B1 (AFB1) was investigated in juvenile hybrid sturgeon Acipenser ruthenus ♂ × A. baeri♀, an important coldwater finfish farmed in China and other countries. Seven experimental diets (Diet A–G) containing different levels of AFB1 (0, 1, 5, 10, 20, 40 and 80 μg kg?1 diet) were fed to juvenile sturgeon weighing 10.53 ± 0.17 g kg?1 to determine its effect on survival, growth, feed consumption, hematocrit, liver histology as well as muscular and hepatic toxin accumulation. The experiment lasted for 35 days and was conducted in two periods of 25 and 10 days each. No external changes or unusual behaviour was observed in the fish fed diets with AFB1. Mortality was observed in fish fed with highest levels of AFB1 (80 μg kg?1– Diet G) from day 12 onwards. After 25 days, fish fed the diet of 80 μg AFB1 kg?1 showed significant lower survival (50 ± 5.77%) followed by those fed 40 μg AFB1 kg?1 diet (80 ± 5.77%) and 20 μg AFB1 kg?1 diet (86.66 ± 3.33%). No significant difference was observed in specific growth rate (SGR) or hepatosomatic index (HSI) between groups. Hematocrit was significantly higher in the fish fed the diet of highest AFB1. The fish were weighed at day 25 in some treatments (Diets F and G) because of high mortality. However, feeding was continued for another 10 days to observe mortality or behavioural changes if any in the other groups. After 35 days, survival in the fish fed Diet F (40 μg AFB1 kg?1) was 40% and those fed Diet E (20 μg AFB1 kg?1) was 36.2%. Significant histopathological changes including nuclear hypertrophy, hyperchromasia, extensive biliary hyperplasia, focal hepatocyte necrosis and presence of inflammatory cells were observed in the liver of fish fed high levels of aflatoxin (40 and 80 μg kg?1). AFB1 accumulation in fish muscle and liver increased with increased dietary AFB1 levels. It could be confirmed that 10 μg AFB1 kg?1 diet was the maximum allowable level in hybrid sturgeon diet.  相似文献   

15.
A 35 days feeding trial was conducted to assess the haemato‐immunological response of Labeo rohita fingerlings fed ethanolic leaf extracts of Psidium guajava and Mangifera indica, and infected with Aeromonas hydrophila. Six iso‐nitrogenous (354.6–361.6 g kg?1) purified diets were prepared with graded level of leaf extracts viz., control (basal feed without any extract); TG‐5 (5 g kg?1 guava extract); TG‐10 (10 g kg?1 guava extract); TM‐5 (5 g kg?1 mango extract); TM‐10 (10 g kg?1 mango extract); and TGM (5 g kg?1 guava extract +5 g kg?1 mango extract). Haematological, immunological, biochemical, along with antioxidant enzyme activities were examined after a 35 day‐feeding trial and following a 7 day challenge with A. hydrophila. The haemoglobin, total leucocyte and erythrocyte counts, respiratory burst activity, lysozyme, total protein, albumin and globulin contents increased significantly (P < 0.05) in leaf extracts fed groups compared with the control in pre‐ and post‐challenge conditions. A significant (P < 0.05) decrease was observed in SOD (superoxide dismutase) and catalase activities of the treatment groups compared with the higher value in control. The trends in mortality indicated that groups of fish showing significantly elevated haemato‐immunological responses had the lowest mortality following challenge with A. hydrophila. The results showed that extracts of P. guajava and M. indica appear to be potential immunostimulant at an inclusion level of 5 g kg?1 in the diet of rohu. But, mixing of both the extract at similar level did not show any synergistic effect, which needs to be tested at its lower level of inclusion.  相似文献   

16.
The effects of a dietary protease‐complex on growth performance, body composition, digestive and immune enzyme activity of Litopenaeus vannamei and its resistance to a pathogenic Vibrio parahaemolyticus were assessed in a 9‐week trial. A high fish meal diet (HF) containing 200 g kg?1 fish meal and a low fish meal diet (LF) containing 100 g kg?1 fish meal were designed as a positive and negative control respectively. Three other diets (LF+125P, LF+150P, and LF+175P) were manufactured by supplementing graded level of a protease‐complex (125, 150 and 175 mg kg?1, respectively) to the LF diet. All diets were formulated to be iso‐proteic and iso‐energetic. Most performance indices of shrimp fed the LF+175P diets were similar to the HF diet. Among the digestive enzymes, trypsin, lipase and amylase activity in hepatopancreas of shrimp fed LF+175P diets (4576 U mg?1 protein and 16, 32 U g?1 protein, respectively) were higher than those fed the LF diets but lower than the HF diets (P < 0.05). Total superoxide dismutase and polyphenol oxidase contents in both serum and hepatopancreas were higher and serum malondialdehyde content and the cumulative mortality during disease challenge tests were lower for the diets containing the protease‐complex than those fed the LF diets (P < 0.05) with no difference with those fed the HF diets.  相似文献   

17.
l ‐ascorbyl‐2‐monophosphate‐Na/Ca (AMP‐Na/Ca) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the post‐larval kuruma shrimp, Marsupenaeus japonicus. Purified carrageenan‐microbound diets with six levels of AMP‐Na/Ca, AsA equivalent to 0, 20, 56, 87, 759 and 1697 mg kg?1 diet were fed to triplicate groups of M. japonicus (mean initial weight 16±0.3 mg) for 30 days. The diets with AsA 0, 20 and 56 mg kg?1 showed high cumulative mortality after 10 days of feeding. After the 30‐day trial, the shrimp fed these diets had significantly lower survival and weight gain (WG, %) than those fed the 87, 759 and 1697 mg AsA kg?1 diets. Specific growth rate and individual dry weight showed the same pattern as WG (%). There were no significant differences in growth performance among the groups fed the AsA levels at 87, 759 and 1697 mg kg?1 at the termination of feeding trial. Broken‐line regression analysis indicated that 91.8 mg AsA kg?1 in the diet was the optimum for post‐larval shrimp. On the other hand, dietary level of more than 800 mg AsA kg?1 was needed to ensure high resistance to stressful conditions such as osmotic and formalin stressors.  相似文献   

18.
An 8‐week feeding trial was conducted to evaluate the efficacy of dietary l ‐ascorbic acid (AA) dosages on immunity, growth and survival of the fingerlings of Labeo rohita. AA was supplemented at 0, 100, 200 and 500 mg kg−1 basal diets. Each diet was fed for 8 weeks to duplicate groups of fingerlings of rohu with initial body weight of 35 ± 5 g. Selected biochemical and haematological analyses were evaluated every second week. At the end of the feeding trial of 56 days, fish were divided into two subgroups under each major treatment group for challenge with two pathogens, Aeromonas hydrophila and Edwardsiella tarda. The mortality (%) and agglutinating antibody titre were recorded on 28th day postchallenge. Non‐specific immune parameters like superoxide anion production, lysozyme activity and complement activity increased independently of the levels of AA in the diet. Whereas phagocytic ratio, phagocytic indices, lymphokine production indices and serum bactericidal activity were better in the group of fish fed with 200 mg AA kg−1 feed for 42 days. However, growth parameters such as specific growth rate, feed conversion ratio and survival were better in the group of fish fed with the highest level of AA through feed for 56 days. These data indicated that elevated levels of dietary AA could be recommended for optimum immunity, growth and survival of fingerlings of L. rohita.  相似文献   

19.
Jatroha protein concentrate (JPC) was prepared by iso‐electric precipitation method. A 45‐day feeding trial was conducted for the nutritional evaluation of JPC and fermented Jatropha protein concentrate (FJPC) in Labeo rohita fingerlings. Seven iso‐nitrogenous (340 g kg?1 CP) and iso‐energetic (17 MJ kg?1) diets such as C (soy protein concentrate), T1 (50 g kg?1 JPC), T2 (100 g kg?1 JPC), T3 (200 g kg?1 JPC), T4 (50 g kg?1 FJPC), T5 (100 g kg?1 FJPC) and T6 (200 g kg?1 FJPC) were fed to respective groups. The weight gain % and protein effciency ratio showed a decreasing trend with higher inclusion of JPC whereas these parameters increased gradually on higher inclusion of FJPC. FCR showed the reverse trend. The protease, GOTand GPT activities of FJPC fed groups were significantly higher than their non‐fermented counterparts whereas a reverse trend was observed for LDH and MDH enzyme activities in muscle and liver. The survival rate was 100% in all the treatment groups except for T2 and T3. Phorbol esters (PEs) in FJPC was non‐detectable. Results suggested that solid state fermentation with Aspergillus niger is an effective method for removal of PEs and FJPC is a promising protein source in aquafeed.  相似文献   

20.
This study was conducted to evaluate effects of dietary Azomite, a natural mineral of volcanic ash, on growth performance, digestive enzyme activities, serum non‐specific immunity and disease resistance of white shrimp (Litopenaeus vannamei). Graded levels of 0.0 g kg?1 (control group), 2.0, 4.0, 6.0 and 8.0 g kg?1 Azomite were supplemented in basal diet to feed shrimps. After 6 weeks feeding, weight gains of the 2.0 and 4.0 g kg?1 Azomite groups were significantly higher than that of the control group (P < 0.05). Compared with control group, the activities of stomach protease, hepatopancreas lipase, and serum alkaline phosphatase, lysozyme and phenoloxidase were significantly increased by the 4.0 g kg?1 Azomite addition (P < 0.05). When subjected to hypoxia stress, the lethal times of the first shrimp and all shrimps were both delayed by the addition of 2.0–6.0 g kg?1 Azomite to diets, compared with the lethal time of control group. At the 96th hour after the injection of bacterium (Vibrio alginolyticus), the accumulated mortality of 4.0 g kg?1 Azomite addition group was 34.6% lower than that of control group (P < 0.05). The results showed that dietary levels of 2.0 and 4.0 g kg?1 Azomite can improve the growth performance, digestive enzyme activities, serum non‐specific immune function and disease resistance of white shrimp.  相似文献   

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