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1.
An 8 weeks growth experiment was conducted to determine the effects of dietary vitamin C on the survival, growth, tissue ascorbic acid contents and immunity of large yellow croaker (Pseudosciaena crocea) with initial weight of 17.82 ± 0.68 g. Seven practical diets were formulated to contain 0.1, 12.2, 23.8, 47.6, 89.7, 188.5 and 489.0 mg ascorbic acid equivalent kg− 1 diet, supplied as l-ascorbyl-2-polyphosphate (LAPP). Each diet was fed to triplicate groups of fish in seawater floating cages (1.5 × 1.5 × 2.0 m), and each cage was stocked with 120 fish. Fish were fed twice daily (05:00 and 17:00) to apparent satiation for 8 weeks. The water temperature fluctuated from 19.5 to 25.5 °C, the salinity from 25 to 28‰ and dissolved oxygen content was approximately 7 mg l− 1 during the experimental period. Results showed that the specific growth rate (SGR) (from 1.80 to 1.96% d− 1) had an increasing trend with the increase of dietary vitamin C, but no significant difference was observed among dietary treatments. No gross deficiency signs were observed in any of the experimental fish. Survival rate, however, significantly increased with increasing dietary vitamin C (P < 0.05). The vitamin C contents in liver and muscle correlated positively with the vitamin C in diets. The vitamin C requirement was estimated to be 28.2 mg kg− 1 based on survival, and 87.0 mg kg− 1 on liver content of vitamin C. The activities of serum lysozyme and alternative complement pathway (ACP), phagocytosis percentage (PP) and respiratory burst activity of head kidney significantly increased with increasing dietary vitamin C. The challenge experiment with Vibrio harveyi showed that fish fed the diets with supplementation of vitamin C had significantly lower cumulative mortality compared to the control group (66.7%), and the cumulative mortality (16.7%) in fish with 489.0 mg kg− 1 ascorbic acid was significantly lower than that (41.7%) in fish with 23.8 mg kg− 1 ascorbic acid. These results suggested that vitamin C significantly influenced the immune response and disease resistance of large yellow croaker.  相似文献   

2.
The effects of dietary α-lipoic acid (LA) and vitamin C on the fatty acid (FA) composition in the brain and muscle and vitamins E and C levels in the brain were studied in the fish Piaractus mesopotamicus. A two-factorial design, where diets were devoid or supplemented with ascorbate (500 mg AA kg− 1) and/or lipoic acid (1000 mg kg− 1), was used. The levels of eicosapentaenoic acid (20:5n − 3, EPA) increased (P < 0.01) in muscle polar lipids (PL) in LA groups (6.93% ± 0.43 vs. 5.83% ± 0.40 and 6.68% ± 0.53 vs. 6.00% ± 0.39), and the same trend was also seen in the brain, however not significant. These changes are suggested to be caused by a change in lipid metabolism rather than being a direct effect of protection by LA against lipid peroxidation. No interaction of vitamin C and LA neither effects of LA on vitamin E (15.1-19.2 mg α-tocopherol g− 1 tissue) or vitamin C (total AA, 41.7-89.8 μg g− 1 tissue) in brain was detected.  相似文献   

3.
The experiment was designed to investigate the dietary factors that might enhance or interfere with astaxanthin (Ax) absorption in salmon including potentially interfering factors such as certain carotenoids (zeaxanthin and lutein), plant sterols, fibre and enhancing compounds such as cholesterol and vitamin E. Two hundred and eighty‐eight salmon (778 ± 78 g) were reared in sea water under controlled conditions and fed practical experimental diets. The experimental diets were supplemented with 40 mg Ax kg?1, in addition to various dietary factors, including cholesterol (2%), vitamin E (450 IU kg?1), wheat bran (5%), lutein (40 mg kg?1), zeaxanthin (40 mg kg?1) and phytosterol (2%). After 26 days of feeding, blood was collected and plasma was separated to determine the plasma Ax concentration. Ax was not detected in the plasma of fish fed the non‐pigmented diet. Fish fed diet containing 2% cholesterol significantly improved Ax absorption, which was reflected in the higher Ax concentration in plasma of Atlantic salmon. Other supplements including vitamin E, wheat bran, lutein, zeaxanthin and phytosterols in diet had no significant effect on plasma Ax concentration . Fish fed diet containing 2% cholesterol significantly increased cholesterol concentration in fish plasma. Phytosterol had no benefit to lower cholesterol plasma level in fish fed 2% phytosterol‐supplemented diet.  相似文献   

4.
A 9-week feeding experiment was conducted to evaluate the effects of dietary vitamin E supplementation on growth, lipid peroxidation and fatty acid composition of black sea bream fed oxidized oil. The FL and OL diets contained fresh fish oil and oxidized oil, respectively, without additional vitamin E supplementation. Another four α-tocopherol levels (150, 250, 450 and 800 mg kg−1 diet) were used within the OL diet, giving a total of six experimental diets. Fish were hand-fed to apparent satiation twice daily. At end of the trial, the weight gain and survival rate of fish were significantly reduced by diets with oxidized oil, whereas hepatosomatic index was remarkably high in fish fed oxidized oil diet. However, vitamin E supplementation to diet significantly improved growth performance and increased vitamin E content in the liver. Although, liver thiobarbituric acid reactive substances and docosahexaenoic acid were significantly increased by dietary oxidized oil, their levels were reduced by dietary vitamin E supplementation. Our results indicate that the fish were performing the best at intermediate concentrations of α-tocopherol and a dose of >150 mg α-tocopherol kg−1 diet could reduce lipid peroxidation and improve fish growth performance when oxidized oils exist in diet.  相似文献   

5.
A study was conducted to determine the effect of increasing dietary levels of fish oil on vitamin E requirement and their effect on growth performance, liver vitamin E status, and tissue proximate and fatty acid compositions of channel catfish. Basal purified diets (42% protein and 3,800 kcal DE/kg) supplemented with 6, 10, and 14% menhaden fish oil were each supplemented with 50, 100, and 200 mg vitamin E/kg (3 × 3 factorial experiment). Each diet was fed to juvenile channel catfish in three random aquaria to apparent satiation twice daily for 12 weeks. Weight gain, feed intake, and feed efficiency ratio were not affected by dietary levels of fish oil, vitamin E, or their interaction. Survival rate at the end of week 12 was significantly lower for fish fed diets containing 14% fish oil, regardless of vitamin E content. Whole-body moisture significantly decreased and lipid increased when dietary lipid levels were increased to 10 or 14%. Dietary vitamin E levels had no effect on body proximate composition. Lipid content of liver was not influenced by dietary levels of fish oil and vitamin E or their interaction. Hepatosomatic index significantly decreased with increasing lipid levels but was not affected by dietary levels of vitamin E. Liver vitamin E increased with increasing dietary vitamin E but decreased with increasing fish oil levels. Fatty acid composition of whole body and liver reflected that of dietary lipid but was not influenced by dietary levels of vitamin E. Whole-body saturates increased, whereas MUFA decreased with increasing dietary levels of fish oil. Liver saturates were not affected by fish oil levels, but MUFA and n-6 decreased and increased, respectively, with increasing fish oil levels. Total n-3 and n-3 HUFA in both tissues increased with increasing fish oil levels in diets, but liver stored much higher levels of these fatty acids.  相似文献   

6.
Juvenile African catfish, Clarias gariepinus (Burchell), of mean initial weight 15 g, were fed practical diets containing fresh or rancid oil (1:1 cod liver:corn oil) supplemented with either 20 or 100 mg all-rac-α-tocopheryl acetate per kg dry diet, at 0.03 × body weight per day for 8 weeks. After this time, catfish had grown by at least four times in body weight. Significant ( P < 0.05) inter-treatment differences in final body weight were noted. Clarias fed low-tocopherol: oxidized-oil diets performed least well with regard to growth, though elevated dietary vitamin E partially abrogated this effect. Growth of fish fed fresh-oil diets did not benefit from increased dietary α-tocopherol content. Muscle, liver, plasma, heart and spleen all responded significantly ( P < 0.05) to dietary vitamin E dose. Inclusion of oxidized oil in catfish diets decreased tissue α-tocopherol concentration. Hepatic α-tocopherol concentration (μg α-tocopherol per g liver) was observed to be lowered by 90% by the rancid oil diets. When fish previously fed fresh-oil diets were switched to oxidized: low-tocopherol diets, hepatic α-tocopherol concentration was significantly ( P < 0.05) lowered within 2 weeks. The results highlight the importance of dietary oil quality in modulating tissue α-tocopherol concentrations in African catfish.  相似文献   

7.
An experiment was conducted to determine the effects of different levels of dietary vitamin C (VC) and E (VE) supplementation on fillet quality of red sea bream fed oxidized fish oil (OFO). Fish with an average body weight of 205.0 g were fed four test diets for 9 weeks. Control diet contained fresh fish oil (FFO) with 100 mg kg?1 of VE and 500 mg kg?1 of VC (FFO100E/500C). The other three diets contained OFO with varying levels of VE (mg kg?1) and VC (mg kg?1) (OFO100E/500C, OFO200E/500C and OFO200E/1000C). After feeding trial, two fillets from each fish by hand filleting were stored in a refrigerator at 4°C for 96 h during analyses. Results showed that fish fed OFO increased fillet thiobarbituric acid reactive substances (TBARS) and K‐value, and decreased fillet VC and VE concentrations during storage time. Supplementation of VC did not have any detectable effect on fillet quality. Increasing dietary VE supplementation increased fillet VE concentrations, reduced fillet TBARS and K‐value values of red sea bream. Therefore, we suggest that dietary supplementation of 200 mg kg?1 of vitamin E could improve fillet oxidative stability of red sea bream fed OFO.  相似文献   

8.
《Aquaculture Research》2017,48(4):1759-1766
A shrimp protein hydrolysate (SPH) containing 894.2 g kg−1 crude protein (CP) and 54.3 g kg−1 total lipids was tested as a partial replacement for fish meal (FM) in diets of juvenile cobia. The effects of increasing dietary levels of SPH on the survival, weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), nitrogen retention efficiency (NRE) and daily feed intake (DFI) of cobia with initial body weight of 11.9 g were evaluated. Four isoproteic (from 431.1 to 439.7 g kg−1) and isoenergetic (20 825–21 347 MJ kg−1) diets were formulated to contain 0 (Control), 120, 240 or 360 g kg−1 of dietary CP derived from SPH. Survival, WG, SGR, FCR, NRE and DFI ranged from 90 to 100%, 40.2–56.5 g, 4.7–6.1% day−1, 1.04–1.54, 26.3–44.0% and 4.7–6.0% fish−1 day−1 respectively. Survival and DFI were not affected by the dietary treatments. On the other hand, fish fed the control diet and the one containing 120 g kg−1 SPH had higher WG, SGR and FCR. Nitrogen retention efficiency was significantly higher for fish fed diets 0 and 120. It is concluded that up to 120 g kg−1 of SPH in cobia diets can be used with no significant effects on feed utilization and fish performance.  相似文献   

9.
A 3 × 3 factorial experiment was conducted on Labeo rohita fingerlings to evaluate the effect of dietary oxidized oil and vitamin E. Nine experimental diets were made, based on three degrees of oil oxidation (fresh oil, low oil oxidation and high oil oxidation), and each level of oxidation was further supplemented with three levels of vitamin E (0, 100 and 1,000 mg/kg). Weight gain% and specific growth rate (SGR) of fish fed fresh fish oil and low oil oxidation level were significantly higher than highly oxidized oil. Moreover, vitamin E supplemented fish also showed better growth performance. Oil oxidation caused a significant reduction in the concentrations of α‐tocopherol and increase in TBARS level and antioxidant enzyme activities in fish liver and muscles. However, increasing the dietary vitamin E abrogated these effects. Dietary vitamin E supplementation improved the fatty acid, more specifically polyunsaturated fatty acids profile of oxidized oil fed fish. In conclusion, dietary oxidized fish oil increased the oxidative stress condition of fish but supplementation of high dose of vitamin E prevented lipid oxidation, improved growth performance and fatty acid profile of L. rohita.  相似文献   

10.
An experiment was conducted in aquaria with channel catfish (Ictalurus punctatus) to determine the efficacy of augmenting fillets with conjugated linoleic acid (CLA) and omega-3 highly unsaturated fatty acids (n − 3 HUFA) by feeding diets amended with products containing high levels of these nutrients. Refined menhaden fish oil at 1.5% of diet supplied the n − 3 HUFA. CLA was used at dietary levels of 0.5% and 1% with a preparation that contained approximately 65% isomers of CLA. Corn oil was added to the basal diet at maximum inclusion level for added lipids of 3% for the control diet and to adjust total added lipid content of the other diets to 3%. Average initial body weight was 57.39 ± 0.25 g/fish. Six experimental diets were fed twice daily to four replicate aquaria for six weeks. At that time, fish were group weighed for determination of weight gain and feed conversion. Fillets of six fish per aquarium were recovered and stored at − 80 °C for moisture and total lipid analyses, fatty acid analysis, and sensory evaluation. Results showed feed consumption and feed conversion did not differ (P > 0.05). Significantly (P < 0.05) greater body weight gains were observed only for fish fed the diets with two combinations of CLA and 1.5% fish oil compared to fish fed the diet containing 0.5% CLA and corn oil. Fillet n − 3 HUFA levels were significantly (P < 0.05) elevated for fish fed diets containing fish oil when compared to n − 3 HUFA of fillets of fish fed diets containing either corn oil or CLA and corn oil. Similarly, fillets from fish fed diets amended with CLA contained substantial amounts of CLA of up to 6.4% of total lipids. Fillets from fish fed corn oil or fish oil diets had no CLA. Taste panel evaluation indicated that fillets containing n − 3 HUFA and CLA were essentially without fishy off-flavor and had excellent sensory qualities. Catfish fillets produced by amending diets with sources of n − 3 HUFA and CLA at the levels used in this study would contain elevated levels of these nutraceuticals and could be an important human food source for these healthful fatty acids.  相似文献   

11.
A 10‐week feeding trial was conducted to evaluate the effect of dietary vitamin E and astaxanthin on growth performance, skin colour and antioxidative capacity of large yellow croaker Larimichthys crocea. Six practical diets were formulated in a 2 × 3 factorial design to supplement with two levels of astaxanthin (25 and 50 mg/kg) and three levels of vitamin E (0, 120 and 800 mg/kg). The results showed that both the highest final body weight and specific growth rate were found in fish fed diets with 120 mg/kg vitamin E supplementation. No significant differences were found in survival rate, feed conversion ratio and protein efficiency ratio among all the treatments (p > .05). Skin lightness (L*) was not significantly affected by dietary treatments (p > .05). Ventral skin redness (a*) of fish fed diet with 25 mg/kg astaxanthin and 0 mg/kg vitamin E supplementation was significantly lower than that of fish fed with other diets. Yellowness (b*) and carotenoid contents both in the dorsal and in the ventral skin were found to be significantly increased with increasing dietary astaxanthin or vitamin E (p < .05), but no significant interactions were found (p > .05). The vitamin E content in liver reflected the dietary vitamin E content. Level of vitamin E content in fish fed diets with 800 mg/kg vitamin E supplementation was significantly higher than that in fish fed with the other diets (p < .05). Liver superoxide dismutase activity and thiobarbituric acid reactive substance levels were found to be decreased with increasing dietary astaxanthin and vitamin E levels, respectively. Levels of reduced glutathione in the liver were found to be increased with increasing dietary vitamin E contents. The total antioxidative capacity in the liver was found to be decreased with increasing dietary vitamin E or astaxanthin contents. In conclusion, adequate dietary vitamin E can improve the growth of large yellow croaker, and the supplementation of astaxanthin and vitamin E benefited the skin coloration and antioxidative capacity of large yellow croaker.  相似文献   

12.
An 8‐week feeding trial was conducted to establish the dietary vitamin E requirement of juvenile cobia. The basal diet was supplemented with 10, 20, 30, 40, 60, 120 mg vitamin E kg?1 as all‐rac‐α‐tocopheryl acetate. The results indicated that fish fed the diets supplemented vitamin E had significantly higher specific growth rate, protein efficiency ratio, feed efficiency and survival rate than those fed the basal diet. It was further observed that vitamin E concentrations in liver increased significantly when the dietary vitamin E level increased from 13.2 to 124 mg kg?1. Fish fed the basal diet had significantly higher thiobarbituric acid‐reactive substances concentrations in liver than those fed the diets supplemented vitamin E. Fish fed the diets supplemented with 45.7 and 61.2 mg kg?1 vitamin E had significantly higher red blood cell and haemoglobin than those fed the basal diet, while fish fed the diets supplemented with 61.2 and 124 mg kg?1 vitamin E had higher immunoglobulin concentration than those fish fed the basal diet. Lysozyme and superoxide dismutase were significantly influenced by the dietary vitamin E level. The dietary vitamin E requirement of juvenile cobia was established based on second‐order polynomial regression of weight gain and lysozyme to be 78 or 111 mg all‐rac‐α‐tocopheryl acetate kg?1 diet, respectively.  相似文献   

13.
Bioavailability of the succinate ester of α-tocopherol has never been investigated with aquatic animals to date. Therefore, a 12-week feeding trial was conducted to compare bioavailability of α-tocopheryl acetate and α-tocopheryl succinate by slope ratio analysis. The semi-purified diets were supplemented with either 0 (basal), 10, 20 and 40 IU vitamin E/kg as all-rac-α-tocopheryl acetate or 10, 20, or 40 IU vitamin E/kg as RRR-α-tocopheryl succinate. Red drum juveniles were conditioned by feeding the basal diet for 8 weeks prior to the experimental period to reduce whole-body tocopherols. Fish initially averaging 12.2 ± 0.4 g/fish (mean ± SD) were fed experimental diets at a rate approaching apparent satiation for 12 weeks. Weight gain and feed efficiency responses of fish fed diets were not significantly altered by the type or level of vitamin E supplemented. However, α-tocopherol levels in liver and plasma were significantly (P < 0.01) influenced by dietary vitamin E level and ester form. The liver retention of α-tocopheryl acetate was 14 times higher than α-tocopheryl succinate, while thiobarbituric acid reactive substances (TBARS) in liver of fish fed α-tocopheryl acetate tended to be (P < 0.1) lower than that of fish fed α-tocopheryl succinate. In addition, plasma ascorbic acid in fish fed graded levels of α-tocopheryl acetate was significantly higher than fish fed graded levels of α-tocopheryl succinate. Fish fed the basal diet and 10 IU α-tocopheryl succinate/kg showed edema in the heart, while fish fed all other diets did not exhibit this pathology. Within the dose range of 0–40 IU/kg diet, hematocrit, neutrophil oxidative radical production and intracellular superoxide anion production of head kidney macrophages were not significantly influenced by α-tocopherol ester or dietary supplementation level. In conclusion, α-tocopheryl succinate is not readily available to juvenile red drum compared to the widely used α-tocopheryl acetate.  相似文献   

14.
Over a 56-day feeding period, during which juvenile African catfish, Clarias gariepinus (Burchell) increased in body weight at least threefold, diets containing fresh or rancid oils (0.352 and 9.133 mmol MDA equivalents per g oil, respectively) at two levels of supplemental vitamin E (20 or 100 mg all-rac-α-tocopheryl acetate kg-1 dry diet) were fed at 3% body weight per day. On termination of the feeding trial, growth performance and food utilization were assessed. Additionally, health criteria such as hepatosomatic index (HSI), haematocrit, plasma haemoglobin and plasma α-tocopherol concentration were determined. Plasma α-tocopherol was seen to increase significantly (P < 0.05) concomitant with dietary dose of the vitamin. Oxidation of dietary lipid source was observed to cause significant depletion (P < 0.05) of α-tocopherol from the plasma pool on consumption of the rancid test-diets. Final body weights of the catfish revealed that vitamin E supplementation in rancid diets significantly improved growth (P < 0.05), although supplementation into fresh-oil diets did not result in appreciable benefits in terms of final attained weight (P > 0.05). Values of other growth parameters and nutrient utilization indices were seen to respond positively to increased vitamin E levels and fresher dietary oils. With respect to other health indices, HSI was strongly correlated (P < 0.05) to dietary vitamin E dose and not oil oxidation state, with catfish fed lower α-tocopherol doses exhibiting larger livers proportional to somatic mass. Haematocrit values were significantly (P < 0.05) lower in fish fed low-tocopherol/fresh-oil diets. Although no measurably significant differences were found between treatments with respect to plasma-haemoglobin concentration, higher mean values for the fish fed rancid oils at the lower α-tocopherol inclusion level may indicate heightened Spontaneous haemolysis in this group. Mechanisms to account for dietary modulation of health indices in catfish under the present dietary regime are postulated. It was concluded that supplemental α-tocopheryl acetate in diets likely to undergo oxidation, would protect catfish from the nutritional stress imposed by rancid oils and increase growth above levels associated with unsupplemented dietary treatments.  相似文献   

15.
Vitamin E supplement is important in protecting lipid oxidation and enhancing immunity of aquatic animals. A 10‐week feeding trial was conducted to evaluate the effect of dietary lipid and vitamin E on juvenile Chinese mitten crab Eriocheir sinensis. The experimental diets included three levels of vitamin E (0, 100 and 300 mg kg?1) and two levels of lipid (6% and 9%). The 9% lipid diet significantly enhanced the body lipid of crabs compared with the 6% lipid diet. The vitamin E concentration of hepatopancreas increased with the increase in vitamin E in the diets regardless of dietary lipid levels. The hepatopancreas fatty acids, especially polyunsaturated fatty acid and highly unsaturated fatty acid, were significantly enhanced by vitamin E supplement or 9% dietary lipid. Vitamin E supplement significantly increased the total antioxidant capacity, superoxide dismutase, lysozyme and phenoloxidase activities of crabs compared with those fed the diets without vitamin E supplement. The hepatopancreas malondialdehyde of crabs fed 100 mg vitamin E kg?1 was significantly lower than those fed 0 or 300 mg vitamin E kg?1. The phenoloxidase activity of crabs fed the 9% lipid diet was significantly higher than those fed 6% lipid, irrespective of vitamin E levels. Vitamin E supplementation increased the bacterial resistance of juvenile crab. This study indicates that dietary lipid and vitamin E supplement do not affect crab growth and survival, but vitatmin E supplement at 100 mg kg?1 can enhance immunity and antioxidant capacity of crab fed 6% or 9% dietary lipids.  相似文献   

16.
Six dietary treatments were prepared in a 3 × 2 factorial design (unsupplemented or supplemented with Se at 1 or 2 mg kg?1 × supplemented with vitamin E at 40 or 180 mg kg?1) and fed to yellowtail kingfish (Seriola lalandi) for 6 weeks to evaluate the effects of dietary Se and vitamin E on growth performance, immune and antioxidant responses and to investigate the potential interaction between these two micronutrients in this species. The results have revealed significantly interactive effects with positive physiological responses. Se significantly increased weight gain of fish fed diets low in vitamin E, but not high in vitamin E, whereas serum lysozyme activity was significantly improved by Se in diets high in vitamin E, but not low in vitamin E. Moreover, there was evidence of myopathy in fish deficient in both Se and vitamin E, but not single deficiency. There was no significant effect of dietary Se, vitamin E or their interaction on survival, antibody titre, feed intake, feed conversion ratio and fillet proximate composition; however, fillet Se and vitamin E were significantly responsive to dietary Se and vitamin E, respectively, and higher dietary Se intakes produced significantly higher red blood cell glutathione peroxidase activity.  相似文献   

17.
Duplicate groups of Atlantic salmon (Salmo salar), kept in saltwater, were fed fish meal based cold-pelleted diets where graded levels of native or extruded non-starch polysaccharides (NSP) from soybeans replaced cellulose, at a total NSP level of 100 g kg− 1 for 28 days. The study also included a diet where defatted soybean meal (SBM) constituted the NSP at a level of 100 g kg− 1 and a reference diet without NSP supplementation.The SBM diet resulted in a significant reduction in faecal dry matter content, apparent digestibilities of starch and organic material, and growth, and an increased faecal output of several elements (K, Na, Zn), compared to all the other diets. Morphological changes were only seen in the intestine of the fish fed the SBM, i.e. the diets holding purified soy-NSP did not induce enteritis. When compared to the diet without NSP, cellulose addition increased faecal dry matter, while inclusion of native soy-NSP reduced it. Dry matter in faeces and apparent digestibility of crude protein decreased in a linear manner, while the digestibility of starch and faecal output of K and Na increased linearly when native soy-NSP replaced graded levels of cellulose from 0 to 100 g kg− 1 feed. When diets with 75 or 100 g kg− 1 of native NSP and extruded soy-NSP were compared, fish fed native soy-NSP had reduced faecal dry matter, higher digestibility of starch, and increased faecal output of Cu, Fe, and K. Dry matter in faeces and faecal output of Cu was lower for the highest inclusion level, while digestibility of starch and faecal output of Mn and K were higher.In conclusion, soy-NSP was inert compared to the fish meal reference, with respect to nutrient digestibilities and intestinal pathologies, but affected faecal mineral excretion in Atlantic salmon.  相似文献   

18.
The effects of oxidized dietary lipid and the role of vitamin E on the growth performance, blood parameters and body composition of juvenile Atlantic cod (Gadus morhua) were evaluated over a 9‐week feeding period. Four isonitrogenous experimental diets containing fresh or oxidized fish oil with or without added vitamin E (α‐tocopherol or mixed tocopherols) were fed to juvenile cod. The oxidized lipid used had a peroxide value of 94 mEq kg?1 oil. No significant (P>0.05) differences in growth performance (weight gain and specific growth rate) or feed utilization (feed consumption and feed efficiency ratio) were observed when oxidized dietary lipid was used. The hepatosomatic index (HSI), viscerosomatic index (VSI) and haematocrit did not show any significant (P>0.05) differences among the treatments. However, erythrocyte osmotic fragility (EOF), referred to as susceptibility to haemolysis, of fish fed oxidized oil without added vitamin E was high in comparison with those fed unoxidized oil. Supplementation with α‐tocopherol appeared to decrease haemolysis, but mixed tocopherols had no significant (P>0.05) effect on EOF. The proximate composition of fish whole body was also affected by diet treatment. Fatty acid composition of liver total lipid reflected that of dietary lipid. Variations in tissue (liver and muscle) fatty acid composition among the treatments followed the same trend as those of the dietary fatty acids. Fish fed fresh oil had a higher proportion of polyunsaturated fatty acids (PUFA) in muscle and liver lipid than those fed oxidized oil. The results suggest that oxidized dietary oil affected juvenile Atlantic cod in certain tissues and that these effects could be alleviated by supplementation of sufficient amounts of vitamin E in the diet.  相似文献   

19.
As has been demonstrated in previous studies, Octopus maya can be fed on artificial diets. In the present study six different diets were assayed. Five diets were designed to test the effect of percentage of inclusion of fish protein concentrate (CPSP: 0, 5, 10, 15, and 20%) and were offered to octopuses as a specifically designed artificial diet. The sixth diet consisted of frozen crab (Callinectes spp) and was used as control diet. Blood metabolites and energy budget of octopuses were evaluated to determine how CPSP levels modulate the digestive capacity and allow retaining energy for growth. Wild animals (316.4 ± 9.8 g) were used in the study. Results showed that CPSP produced a positive specific growth rate (SGR, % day− 1) with high value in octopuses fed 15% CPSP level. A maximum growth rate of 0.86% day− 1 was recorded in these animals, a value that is extremely low when compared with the SGR obtained when animals were fed fresh crab (3.7% day− 1). In general, blood metabolites were affected by diet composition, indicating that some metabolites could reflect the nutritional and/or physiological status of octopus. Preliminary reference values for O. maya fed crab were found for glucose (0.09 ±0.02 mg/ml), lactate (0.004 ± 0.002 mg/ml), cholesterol (0.16 ± 0.02 mg/ml), acylglycerol (0.14 ± 0.01 mg/ml), protein (0.37 ± 0.04 mg/ml), hemocyanin (1.85 ± 0.04 mmol/l), and digestive gland glycogen (1.86 ± 0.3 mg/g). Total energy content can be used as an indicator of tissue metabolic reserves. In the present study, higher energy content in the digestive gland and muscle was observed in octopuses fed crab, followed by animals fed 15% CPSP. Results from the digestive gland indicated that the retained energy derived from glycogen, suggesting that lipids and protein were the main sources of variation linked with energy content. In general, digestive gland proteases activity and trypsin were induced in octopuses fed 15% CPSP. The capacity of O. maya juveniles to adjust their digestive enzymes to different types of food was evidenced. Essential amino acid content (EAA) of the diet was not a limiting factor. When dietary EAA profiles were compared with O. maya EAA profiles, all dietary EAA resulted in a higher concentration than whole body octopus composition. In the present study, all experimental groups ingested between 3300 and 4106 kJ wk− 1 kg− 1 without statistical differences among treatments, indicating that experimental diets were as attractive as crab. Differences were recorded in the proportion of absorbed energy (Ab, %) between CPSP-based and crab meat diets, suggesting digestion limitations associated with artificial diets. The present results indicate that the 15% CPSP diet had characteristics that stimulate digestive enzymes and reduce energetic costs associated with its digestion (HiE or SDA), channeling more biomass production than the other experimental diets.  相似文献   

20.
Two feeding trials were conducted to determine the minimum dietary protein level producing maximum growth, and the optimum protein to energy ratio in diets for red porgy (Pagrus pagrus) fingerlings, respectively. In the first trial, six isoenergetic diets were formulated with protein levels ranging from 400 to 650 g kg?1 in increments of 50 g kg?1, and fed for 11 weeks to 2.8 g average initial weight fish. Weight gain, specific growth rate and feed efficiency were significantly higher with diets containing higher protein levels, when compared with dietary levels below 500 g kg?1. The highest protein efficiency ratios were obtained in fish fed 500 g kg?1 dietary protein. The minimum dietary protein level producing maximum fish growth was found to be 500 g kg?1. In the second trial, 15 g average initial weight fish were fed for 12 weeks, six diets containing three different lipid levels (100, 150 and 200 g kg?1) combined with two protein levels (450 and 500 g kg?1). Weight gain values increased when dietary lipids increased from 100 to 150 g kg?1, with a further decrease for 200 g kg?1 lipids in diets; the lowest fish growth being supported by 200 g kg?1 dietary lipids. Fish growth was significantly higher when dietary protein increased from 450 to 500 g kg?1. There was no evidence of a protein‐sparing effect of dietary lipids. Liver protein and lipid contents were low when compared with other fish species. All diet assayed produced high liver glycogen accumulation. The recommended protein and lipid levels in diets for red porgy fingerlings were 500 and 150 g kg?1, respectively.  相似文献   

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