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1.
Broodstock of Atlantic cod were fed with three diets; astaxanthin supplemented (100 ppm kg?1) hydrated diet (30% water) (HWHAs), no additional astaxanthin supplemented (50 ppm kg?1) hydrated diet (30% water) (HWLAs) and a control diet (50 ppm kg?1 astaxanthin and 10% water). Throughout the spawning period, eggs were collected daily and fertilization success and proportion of embryos with normal cleavage were recorded. Larvae were reared using standard culture methods. Larval growth was recorded every 10 days and larval survival was recorded at 50 days post hatch. In general, broodstock fed with diets containing higher water content (HWHAs and HWLAs) and higher astaxanthin (HWHAs) had higher egg production and efficiency of egg output, lower egg incubation mortality and higher larval growth and survival. Broodstock fed with higher water content diets consumed less feed compared to control group. Also, broodstock fed with HWHAs and HWLAs recovered faster in terms of body condition than the control group. The egg bound mortality of female fish was significantly higher in control broodstock compared to broodstock fed with HWHAs and HWLAs. Broodstock fed with higher astaxanthin (HWHAs) had significantly higher fertilization success than other two groups however; no differences were found in proportion embryos with normal cleavage among different groups. Larval survival was significantly higher in HWHAs broodstock compared to other two groups. Our results showed that increased water content and astaxanthin levels in the diet could improve the condition and fecundity of Atlantic cod broodstock.  相似文献   

2.
Aquaculture production of the cleaner shrimp Lysmata amboinensis, a high‐valued marine ornamental, has been problematic because of prolonged larval development punctuated by periods of mortality. Broodstock maturation diets have been shown to affect fecundity and offspring quality and early survival. The common practice in shrimp culture is the use of fresh frozen foods supplemented with artificial diets. The objective of the study was to identify a suitable maturation diet (natural or artificial) for L. amboinensis. Six diets, comprised of squid, mussel, adult Artemia, a commercial feed, and combinations of the aforementioned, were fed to L. amboinensis for four reproductive cycles. Broodstock fed the squid–mussel diet lost a large proportion of the eggs during incubation, with decreased larval production (P < 0.05). In contrast, broodstock fed Artemia retained the highest proportion of the egg mass; however, hatchability was poor, resulting in low larval numbers per hatch. The Artemia and squid–mussel diets produced significantly fewer larvae than the combination or commercial diets (P < 0.05). In L. amboinensis, a maturation diet consisting of natural feeds alone resulted in poor reproductive performance and partial or complete replacement with an artificial diet was feasible.  相似文献   

3.
Cultivated Atlantic cod (Gadus morhua) entering their first year of gamete maturation were fed diets with different levels of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) for 6.5 months prior to commencement of spawning. Gravid females were stripped three times: at the beginning, peak and end of spawning. Lipid composition and egg and larval quality of 34 family crosses were investigated. Results indicated that ARA uptake into eggs from broodstock diet was highly efficient achieving proportions of ARA up to 84% higher in eggs than in the diet. EPA was 42–76% higher, and DHA was 155–173% higher in eggs than in diets. Cod fed the diet with the lowest EPA/ARA ratio had the greatest egg production. Eggs from fish on a diet with high ARA level had significantly higher fertilization and hatching success than those fed low levels of ARA. This diet produced on average 71 viable eggs g?1 female compared with 32.5 and 4 eggs in diet B and C, respectively. Furthermore, larval survival until 8 days posthatch was higher in diets with lower ARA levels. The combined results showed that ARA dietary supplementation and low EPA/ARA ratio yielded a greater number of viable larvae kg?1 female.  相似文献   

4.
This study investigated the effect of dietary astaxanthin supplementation on egg quality and juvenile growth of long snout seahorse (Hippocampus guttulatus). Captive breed seahorse broodstock were fed four diets composed of frozen shrimp [Atlantic ditch shrimp, Palaemonetes varians) used as a vector to deliver artificial diets with increasing levels of astaxanthin (0, 75, 100 and 125 mg kg?1 dry weight)]. The results indicated that the astaxanthin uptake into eggs from the enriched shrimp diets was highly efficient. Females fed unsupplemented astaxanthin diet produced similar‐sized eggs with lower concentration of astaxanthin than females fed diets with astaxanthin. The lower concentration of astaxanthin in the eggs was correlated with the production of smaller juveniles in comparison with the juveniles hatched from parents fed supplemented astaxanthin diets. Juvenile growth and survival was limited by their size on release from the male's pouch as at the end of 28‐day postparturition juveniles produced with the diet with no astaxanthin were still significantly smaller (P < 0.05) than those produced from parents fed astaxanthin‐supplemented diets. These results demonstrate a significant benefit of dietary astaxanthin supplementation in long snout seahorse diets in terms of improved egg quality and juvenile growth and survival.  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 360‐day feeding trial was conducted to observe the influence of varying levels of dietary protein on growth, reproductive performance, body and egg composition of rohu, Labeo rohita. Twenty fish (40.4 ± 0.24 cm; 852 ± 4.9 g), stocked in outdoor concrete tanks (200 m2), in duplicate, were fed diets with varying levels (200, 250, 300, 350 and 400 g kg?1) of crude protein exchanged with carbohydrate to apparent satiation, twice daily, at 09:00 and 17:00 h. Higher (P < 0.05) weight increment was discernible in fish fed dietary protein ≥300 g kg?1. Gonadosomatic index was comparable (P > 0.05) among fish of different dietary groups except those fed 200 g kg?1 protein diet which produced least values. Egg diameter remained unaffected (P > 0.05) by variations in levels of dietary protein. Relative fecundity was maximum (P < 0.05) in fish fed 250 and 300 g kg?1 protein diets. With the exception of fish fed 200 g kg?1 protein diet, fertilizability (%) remained unaffected (P > 0.05) by variations in dietary protein level. Hatchability (%) followed the trend of variations almost similar to that of fertilizability. Proximate composition of muscle and eggs varied significantly (P < 0.05) with dietary protein levels. For broodstock L. rohita, a dietary protein level of 250 g kg?1 was found optimum with regard to its reproductive performance, egg quality and composition.  相似文献   

7.
Five diets that contained fresh squid meat as the basic constituent and were supplemented with different amounts of highly unsaturated fatty acids (HUFA) and astaxanthin were fed to pond‐reared Penaeus monodon broodstock. Diet A was sole squid meat. Diets B and C were supplemented with astaxanthin 50 and 100 mg kg?1 respectively. Diets D and E were supplemented with HUFA 5 and 10 g kg?1 and astaxanthin 50 mg kg?1 respectively. The result showed that the group fed diet E had the best reproductive performance in all experimental groups. It had a higher proportion of spawns (71.5%), spawning rate (0.047), a shorter latency period (7.7±0.3 d), higher absolute fecundity (× 103) (361.6±5.5) and egg production/female (× 103) (597.0±18.0) than all the other experimental groups. The fatty acid composition in broodstock diets strongly affected the tissue and fecundity of broodstock. Good correlations between the content of 20:4n‐6 in eggs and the fecundity (r2=0.6109) and egg production (r2=0.9876) of broodstock were found. On the other hand, 22:6n‐3 and DHA/EPA ratio was negatively correlated with the fecundity of broodstock (r2=0.5362, 0.8702 respectively). The result also showed that the balance between n‐3 and n‐6 fatty acid families, total polyunsaturated fatty acids and total saturated fatty acid and 20:5n‐3 (EPA) and 22:6n‐3 (DHA) may play vital roles in maturation and reproductive performance of P. monodon broodstock.  相似文献   

8.
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   

9.
Twelve pelleted diets containing a range of protein and energy levels from 30% protein, 400 kcal gross energy per 100 g diet to 40% protein and 520 kcal gross energy per 100 g diet were formulated. A least-cost linear programming package was applied to determine the optimum inclusion levels of some locally available ingredients. The essential amino acid constraints applied to the diets were based on the essential amino acid content of the eggs of broodstock Macrobrachium rosenbergii (de Man). The study was undertaken using 13 one-tonne capacity fibreglass tanks, each with a water recycling system. Each tank was partitioned into three equal compartments by nylon netting; each compartment was stocked with six female and one male prawn which were fed with the various diets at 2% body weight daily split into three feedings at 0800, 1200 and 1800 h. The results indicated that prawn fed the 40% protein diet with an energy level of 400 kcal per 100 g diet attained the highest fecundity, producing 1355 eggs per gram body weight, followed by those fed P40 with a gross energy level of 440 kcal 100 g-1 (1354 eggs per gram body weight), and prawns fed control diet (30% protein with an energy level of 442 kcal 100 g diet-1) attained the lowest fecundity (1080 eggs per gram body weight). However, statistically, no significant differences in fecundity were observed among prawn fed 35% protein diet with an energy level of 473 kcal 100 g-1, 40 with energy levels of 400 or 440 kcal 100 g diet-1. The essential amino acids index (EAAI) were calculated and were found to be a possible method of evaluating the broodstock diet of M. rosenbergii as a higher index indicates higher egg production. Therefore, a diet containing 40% protein, with an energy level of 400 kcal 100 g diet-1 is recommended as a broodstock feed for M. rosenbergii in view of its superior performance and cost.  相似文献   

10.
A 8‐week feeding experiment was conducted to evaluate the effect of different dietary protein and lipid levels on growth and energy productive value of juvenile Litopenaeus vannamei, at 30 and 2 ppt, respectively. Nine practical diets were formulated to contain three protein levels (380, 410 and 440 g kg?1) and three lipid levels (60, 80 and 100 g kg?1). Each diet was randomly fed to triplicate groups of 30 shrimps per tank (260 L). The effects of salinity and an interaction between dietary protein level and lipid level on growth and energy productive value of shrimp were observed under the experimental conditions of this study. At 30 ppt seawater, shrimp fed with 440 g kg?1protein diets had significantly higher weight gain (WG) than those fed with 380 g kg?1 protein diets at the same dietary lipid level, and the 60 g kg?1 lipid group showed higher growth than 80 g kg?1and 100 g kg?1 lipid groups at the same dietary protein level. At 2 ppt seawater, the growth of shrimp was little affected by dietary protein treatments when shrimp fed the 80 and 100 g kg?1 lipid, shrimp fed the 80 g kg?1 lipid diets had only slightly higher growth than that fed 60and 100 g kg?1 lipid diets when fed 380 and 410 g kg?1 dietary protein diets. A significant effect of salinity on growth of shrimp was detected with the growth responses at 30 ppt > 2ppt (P < 0.05). Final body lipid content, body protein content and energy productive value of shrimp was significantly higher in animals exposed to 30 ppt than in shrimp held at 2 ppt.  相似文献   

11.
Despite carotenoids and essential fatty acids seem to play important roles in fish reproduction, no studies have yet been conducted to determine the effect of dietary carotenoids on gilthead seabream broodstock performance and their relation as antioxidants with dietary n‐3 highly unsaturated fatty acid (HUFA) levels. In addition, the high cost of synthetic sources of carotenoids is leading to the search for new natural carotenoid sources such as paprika oleoresin. Four experimental diets containing two combined levels of carotenoids from paprika oleoresin (40 and 60 mg kg?1) and n‐3 HUFA (25 and 40 g kg?1) were respectively fed to triplicate groups of gilthead seabream (Sparus aurata) broodfish. Elevation of n‐3 HUFA dietary levels from 25 to 40 g kg?1 significantly improved gilthead seabream broodstock performance in terms of egg viability, hatching rates and fecundity. Besides, it markedly increased egg contents in HUFAs which play important energetic and structural roles and improve embryo development. Both arachidonic acid and eicosapentaenoic acid (20:5n‐3) egg contents were more readily affected by dietary n‐3 HUFA than docosahexaenoic acid. HUFA levels did not caused any negative effect suggesting an optimized content of antioxidants in broodstock diets. Increase in dietary carotenoids from 40 to 60 mg kg?1 increased carotenoid contents in eggs and significantly improved egg fertilization rates suggesting an important sperm cell’s protective role by reducing the risk of lipid peroxidation which is detrimental for sperm motility. The increased inclusion of dietary paprika oleoresin enhanced egg carotenoid deposition and improved fish reproductive performance, denoting the high nutritional value of this product as a source of carotenoids for broodstock of this species.  相似文献   

12.
维生素E、C和HUFA交互作用对中华绒螯蟹生殖性能的影响   总被引：10，自引：3，他引：10  
艾春香 《水产学报》2002,26(6):533-541
通过投喂添加或不添加VE、VC和HUFA的四组实验饲料,经198d饲养实验,以雌蟹的性腺系数、产卵力、孵化率、各组织超氧化物歧化酶(SOD)活性和过氧化产物丙二醛(MDA)含量等为指标,研究这两类营养素交互作用对其生殖性能的影响。结果表明,VE、VC和HUFA对雌蟹生殖性能有显著的影响(P<0.05):在产卵力方面,1组为3790个卵细胞·g-1体重,极显著高于2组(为2317个卵细胞·g-1体重)和3组(为2129个卵细胞·g-1体重)(P<0.01),显著高于4组(为3050个卵细胞·g-1体重)和5组(对照组)(为3010个卵细胞·g-1体重)(P<0.05);而孵化率方面,1组(86.17%)极显著高于2组(36.06%)、3组(29.18%)和4组(25.73%)(P<0.01),也显著高于5组(71.12%)(P<0.05)。1组和2组雌蟹性腺中SOD活性分别为40.09Nu·mL-1和39.87Nu·mL-1,相应地,MDA含量分别为6.87nmol·mL-1和3.33nmol·mL-1;而3组和4组雌蟹,尽管其性腺中SOD活性较高,分别为79.21Nu·mL-1和85.2Nu·mL-1,但由于饲料中抗氧化性VE、VC的缺乏,导致脂质过氧化发生,其MDA含量显著增加(P<0.05),分别为12.65nmol·mL-1和25.18nmol·mL-1。4组雌蟹的产卵力较大,但因VE、VC的缺乏发生脂质过氧化,导致所产的卵质低下,从而影响了卵子的孵化率。结果表明,VE、VC和HUFA都是河蟹保持良好的生殖性能的必需营  相似文献   

13.
A study was conducted to determine the effect of essential fatty acid in striped catfish (Pangasianodon hypophthalmus) broodstock diets on a level of oestradiol‐17β and vitellogenin, reproductive performance and larval quality in out‐of‐spawning season. Five female and five male broodstock were stocked into a net cage (3 × 5 × 1.5 m3) and fed with pelleted diets containing 1.5% fish oil and different amounts of corn oil (CO) in diet formulation, that is 0%, 1%, 2% and 3% respectively. Gonadal development, oestradiol‐17ß and vitellogenin concentrations were examined every 2 weeks. Oestradiol‐17ß and vitellogenin concentrations showed an increase during the maturation process. The significantly highest percentage of female mature, fecundity, hatching rate, larval production and larval survival rate were obtained from fish fed with 2% corn oil in the diet. This result revealed that the administration of 2% corn oil in the diet as a source of n‐6 (linoleic acid) and 1.5% fish oil as a source of n‐3 (linolenic acid) can improve the reproductive performance of striped catfish broodstock in out‐of‐spawning season.  相似文献   

14.
This study was conducted to evaluate the effects of supplemental taurine on reproductive performance of Nile tilapia (Oreochromis niloticus) broodstock fed soybean meal‐based diets. Four isonitrogenous (350 g kg?1 protein), isocaloric (18 MJ kg?1) diets were formulated to contain 0, 5, 10 and 15 g kg?1 taurine. The diets were fed to triplicate groups of juvenile Nile tilapia (10–15 g average body weight) at a female: male ratio of 3 : 1, to apparent satiation, three times per day for 130 days. The size at first maturation decreased with increasing dietary taurine to 10 g kg?1 and levelled off with further taurine supplementation. The time to first spawning was also significantly shorter at 10 g kg?1 taurine level. Spawning performances, including spawning frequencies, total number of spawnings per tank, number of spawnings per female and absolute fecundity, were all significantly improved with increasing dietary taurine up to 10 g kg?1. However, the quadratic regression analyses indicated that the maximum spawning performance occurred at 8 g kg?1 of supplemental taurine. Eggs produced from broodstock fed 10 g kg?1 taurine exhibited significantly higher hatchability and required shorter time for hatching and yolk‐sac absorption and also resulted in higher larval weight than at other dietary taurine levels. The highest egg protein, total amino acids and taurine were also obtained at 10 g kg?1 taurine. These results suggest that 8 g kg?1 dietary taurine is required for optimum reproductive outputs of Nile tilapia broodstock.  相似文献   

15.
A growth trial was conducted to determine the effects of inclusion of whole shrimp floc or floc fractions to a control diet on growth and survival of shrimp (Litopenaeus vannamei). The floc sample was collected from marine shrimp culture tanks and partially fractionated by extraction with water, acetone and hexane. A series of diets was manufactured by inclusion of whole floc (intact or ground), each of the fractions or their combination to a control diet. These diets were fed to shrimp (approximately 1.0 g) in an indoor laboratory under flow‐through conditions for 8 weeks. It was found that addition of whole floc (200 g kg?1) or floc fractions (24–200 g kg?1) to the control diet improved (P < 0.05) shrimp growth rate without affecting (P > 0.05) shrimp survival (>81.3%). Although inclusion of whole floc reduced the crude protein and crude fat contents and gross energy of the control diet, shrimp fed the whole floc‐supplemented diets obtained the highest (P < 0.05) growth rates (1.01 and 1.03 g week?1) among the shrimp fed the 11 tested diets including two control (0.81 and 0.85 g week?1), two commercial (0.45 and 0.71 g week?1) and five floc‐fraction‐added (0.91–1.00 g week?1) diets. Many bioactive compounds in the floc that possibly affected shrimp growth were also analysed and quantified.  相似文献   

16.
The present study investigated the effects of propolis and vitamin E supplementation in diets of juvenile rainbow trout subjected to two different flow rates (0.9 and 2.1 L min?1) on growth performance, and vitamin A, C and E concentrations in tissues as well as malondialdehyde (MDA) levels. Juvenile rainbow trout were fed with diets containing 10 and 30 g propolis kg?1, 60 mg kg?1 vitamin E (Rovimix E‐50 adsorbate; min.%50 dl‐α‐tokopherly acetate) and without supplemented basal diet for 12 weeks. Weight gain (WG) in the C group was significantly lower (P < 0.05) than P10, P30 and E60 groups at both flow rate treatments. At 2.1 L min?1, specific growth rate (SGR) in the C group was significantly lower (P < 0.05) than other groups, but at 0.9 L min?1, SGR of fish did not differ among the diets groups (P > 0.05). Survival rate (SUR) was higher in propolis and vitamin E supplemented diet groups (P < 0.05) than control diet group at 0.9 L min?1. Fish fed on diet E60 had higher (P < 0.05) tissue vitamin E concentration than fishes fed on other diets groups. Vitamin C concentration in rainbow trout tissues was significantly affected by the 30 g propolis supplemented diet group (P < 0.05), followed by the 10 g propolis supplemented diet group (P < 0.05). MDA level of E60 group was found significantly decreased instead of different than other groups (P < 0.05). The results of Student's t‐test revealed that WG, SGR, SUR values, vitamin (A, C, E) concentrations and MDA levels of tissues were negatively affected by 0.9 L min?1flow rate treatment in juvenile rainbow trout.  相似文献   

17.
The study was conducted to determine the effect of dietary supplementation of vitamin C on anti‐acid stress ability in juvenile soft‐shelled turtle. The soft‐shelled turtles were fed vitamin C supplemented diets at levels of 0, 250, 500, 2500, 5000 and 10 000 mg kg?1 for 4 weeks. The results showed that the phagocytic rate of blood cell in the group fed vitamin C deficient diets, the serum bacteriolytic activity in the two groups fed vitamin C supplemented diet at 0 and 250 mg kg?1 and the serum bactericidal activity in all groups after acid stress significantly decreased compared with those of before stress (P < 0.1). The phagocytic rate of blood cells in the two groups fed vitamin C supplemented diet at 2500 and 5000 mg kg?1 were significantly higher than those of the four groups fed at 0, 250, 500 and 10 000 mg kg?1 (P < 0.01). The serum bacteriolytic activity in the groups fed vitamin C supplemented diet at 500, 2500, 5000 and 10 000 mg kg?1 were significantly higher than that of the group fed vitamin C deficient diets (P < 0.05), and the two groups fed vitamin C at 2500 and 5000 mg kg?1 were significantly higher than those of the groups fed at 250 and 10 000 mg kg?1 (P < 0.05). The serum bactericidal activities in the four groups fed vitamin C supplemented diet at 500, 2500, 5000 and 10 000 mg kg?1 were significantly higher than those of the two groups fed at 0 and 250 mg kg?1 diet (P < 0.01), and the two groups fed vitamin C at 2500 and 5000 mg kg?1 were significantly higher than those of the two groups fed at 500 and 10 000 mg kg?1 (P < 0.1). These results suggest that supplementation of vitamin C higher than 250 mg kg?1 is necessary to reduce the adverse effects of acid stress.  相似文献   

18.
The ability of Litopenaeus vannamei (initial mean weight: 0.96 ± 0.02 g) to utilize different levels of cornstarch was examined in terms of growth indices, body composition, digestibility and microscopic structure of the hepatopancreas. Six isonitrogenous semipurified diets were fed to satiation to shrimp for 8 weeks in triplicate tanks (30 shrimps per tank) connected to a natural brackish water (6–8 g L?1) recirculating system. Diets contained different levels of cornstarch (100, 150, 200, 250, 300 and 350 g kg?1) as the source of carbohydrate and were balanced using cellulose. Weight gain (WG), survival rate and feed conversion rate (FCR) were considerably affected by cornstarch levels of diets. The highest WG (453.6 g kg?1) and best FCR was observed in shrimp fed the 150 g kg?1 (cornstarch level) diet and was significantly (P < 0.05) higher than those fed diets containing 250–350 g kg?1 cornstarch. However, the survival rate reached maximum in shrimp fed the 100 g kg?1 diet (96.7), some 30% higher than the lowest rate, which was found in shrimp fed the 250 g kg?1 diet. Body lipid tended to be higher in shrimp fed diets with higher cornstarch levels. The apparent digestibility of dry matter and crude fat increased with increasing levels of cornstarch and, hence, decreasing levels of cellulose. In addition, histological study on shrimp fed 10–350 g kg?1 diets exhibited histological changes. The overall conclusion was that the optimum cornstarch level may be set at 100–200 g kg?1 when the diets contain 380 g kg?1 protein.  相似文献   

19.
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   

20.
Knowledge on the biochemistry of proteins and amino acids (AA) of eggs and larvae of echinoids is scarce and the possibility to modify their profiles by diet manipulations is unknown. The protein content of eggs, prisms and pre‐plutei and the amino acid composition of eggs of Paracentrotus lividus from captive broodstock fed prepared diets were analysed and compared with the ones obtained from wild broodstock. Diets differed on protein source (fish or soy meals) and on protein content (10–40% dry weight – DW). Total and soluble protein content of both eggs and larvae was higher than 400 g kg?1 DW and 200 g kg?1 DW respectively. Glycine was the most abundant free AA. Very few differences were found among P. lividus eggs and larvae biochemical parameters, suggesting that their AA composition can hardly be changed by broodstock diet manipulations.  相似文献   

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