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1.
The role of dietary linolenic acid (LN), vitamin E (E) and vitamin C (C) in regulating fish growth and immune response was tested on juvenile darkbarbel catfish Pelteobagrus vachelli. Five dietary combinations were used (?E?LN, +E?LN, ?E+LN, +E+LN and ?C+E+LN; ‘+’ with addition and ‘?’ without addition) in triplicate. Weight gain was highest in the ?E+LN feeding group. Red blood cell in fish fed the +E+LN diet was highest. The haematocrit and haemoglobin of fish fed the ?E+LN diet was lowest. Superoxide dismutase, catalase, glutathione peroxidase and glucose‐6‐phosphate dehydrogenase activities in fish fed the ?E+LN diet were higher than those in fish fed other diets. Malondialdehyde in fish fed the ?C+E+LN diet was highest. Fish fed the +E+LN diet had higher levels of lysozyme activity, serum protein, complements C3 and C4, and immunoglobulin contents than fish fed other diets. Fish fed the +E+LN diet showed lower mortality and higher antibody titre than fish fed other diets after the fish were challenged with Aeromonas hydrophila for 14 day. This study suggests that the growth of darkbabel catfish is improved by increasing dietary linolenic acids. The diets with high linolenic acid, vitamin E and vitamin C can enhance the immune response and resistance in darkbarbel catfish challenged with A. hydrophila.  相似文献   

2.
To evaluate the effects of dietary linoleic (LA) and linolenic acids (LN) on growth, enzyme activities to lipid addition and antioxidant capacity of the Russian sturgeon, Acipenser gueldenstaedti, 10 diets with different sources of lipid were formulated. Coconut oil in the basal diet was replaced by sunflower oil to make three diets (LA0.5 + LN0, LA1.0 + LN0 and LA2.0 + LN0) with dietary LA at 0.5%, 1.0% and 2%, by perilla oil to obtain three diets (LA0 + LN0.5, LA0 + LN1.0 and LA0 + LN2.0) with dietary LN at 0.5%, 1.0% and 2%, and by the combination of sunflower oil and perilla oil to provide three diets (LA0.25 +LN0.25, LA0.5 + LN0.5 and LA1.0 + LN1.0) containing LA and LN at 0.25, 0.50 and 1.00%. Coconut oil was used as the control diet at 10%, but without LA and LN (LA0 + LN0). After feeding for 56 days, the fish whole body, the serum and the liver of sturgeon were sampled. Fish fed LA0 +  LN0 and LA0 + LN2.0 gained lowest weight but was not significantly different from the fish fed LA0 +  LN1.0. Fish fed LA1.0 + LN1.0 gained highest weight among all groups. Feed conversion ratio was the best in fish fed LA1.0 +  LN1.0. Survival, condition factor and viscerosomatic index did not differ among treatments. Total body n‐6 fatty acids increased with the levels of n‐6. Total body n‐3 fatty acids also increased with dietary n‐3, and fish fed 2.0% LN had the highest content of total body n‐3 fatty acids among all groups. Triglyceride and cholesterol in the serum of fish fed LA1.0 +  LN1.0 were lowest. Fish fed LA1.0 +  LN1.0 showed the highest lipoprotein lipase and lipase activities, but the lowest malate dehydrogenase activity. Fish fed LA1.0 +  LN1.0 showed higher catalase, superoxide dismutase activity and total antioxidant capacity than fish fed other diets. This study indicates that diets containing both LA and LN are best for the growth of Russian sturgeon. The level of LA1.0 + LN1.0 in the diet is most beneficial for growth performance and antioxidant capacity in juvenile Russian sturgeon.  相似文献   

3.
A 12‐wk experiment was conducted to determine the dietary biotin requirement of the fingerling Catla catla (7.9 ± 0.37 cm; 3.5 ± 0.12 g). Eight diets (35% crude protein, 16.72 kJ/g gross energy) with different levels of biotin (0, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, and 2.5 mg/kg diet) were fed to triplicate groups of fish to apparent satiation. Highest percent weight gain, protein retention efficiency, and best feed conversion ratio were observed in fish fed 0.5 mg biotin per kg diet. However, fish fed diets containing dietary biotin of 1.0, 1.5, 2.0, and 2.5 mg/kg did not show significant (P > 0.05) differences compared to those fed on dietary biotin of 0.5 mg/kg. Hematological indices, including hematocrit value, hemoglobin content, and red blood cell counts were found to be directly proportional (P < 0.05) to the dietary biotin levels up to 0.5 mg/kg, beyond which a plateau was recorded. Pyruvate carboxylase activity (PCA) was also found to increase with the incremental levels of dietary biotin up to 0.5 mg/kg and further increasing dietary biotin concentration led to stagnation in PCA of fish. Liver biotin concentrations responded positively (P < 0.05) until saturation, which occurred at 1.0 mg/kg diet. Broken‐line analysis of percent weight gain, protein retention efficiency, PCA, and liver biotin concentrations demonstrated that fingerling C. catla require biotin in the range of 0.41–0.87 mg/kg diet.  相似文献   

4.
The effects of dietary supplementation of graded level (0, 0.25, 0.5, 1.0, and 2.0 ml/kg diet) of Citrus aurantium essential oil (EOCA) on the growth, metabolic, and oxidative parameters of silver catfish (Rhamdia quelen) were investigated in a 60‐day growth trial. Fish fed with 2.0 ml EOCA per kg exhibited significantly better growth performance than those fed the control diet. Glucose, lactate, and protein levels in liver and muscle were altered significantly by dietary addition of EOCA. Hepatic lipid peroxidation levels, measured using thiobarbituric acid reactive substance and lipid hydroperoxides assays, were reduced in animals receiving the diet containing EOCA. Superoxide dismutase activity was higher, while glutathione S‐transferase activity was lower in the liver of fish receiving 0.5, 1.0, and 2.0 ml EOCA per kg of diet than in control. The nonprotein thiols content was higher in fish receiving the EOCA‐containing diet. Thus, dietary addition of EOCA improved growth, biochemical, and antioxidant parameters in silver catfish and could be useful as dietary supplement.  相似文献   

5.
A nutrition trial with striped catfish (Pangasianodon hypophthalmus) juveniles was undertaken to evaluate the effect of replacing dietary fishmeal (FM) protein with corn gluten meal (CGM). A diet with FM as the main protein source was used as the control diet (FM). Five experimental diets (approximately 320 g kg?1 crude protein) were formulated to progressively replace 20% (CGM20), 40% (CGM40), 60% (CGM60), 80% (CGM80) and 100% (CGM100) of FM protein. Fifteen fish per tank (initial weight 11.2 ± 0.6 g) were randomly distributed into 18 80‐litre fibreglass tanks connected to a closed recirculation system (temperature 30.3 ± 1.0 °C). The diets were tested in triplicate for 12 weeks. The final weight and specific growth rate (SGR) of fish fed diets CGM20, CGM40 and CGM60 were not significantly different compared to fish fed the FM diet. Feed intake (FI) tended to decrease with increasing dietary CGM level. Striped catfish fed FM, CGM20 and CGM40 had significantly lower feed conversion ratio (FCR) compared with fish fed CGM80 and CGM100 (P < 0.05). The protein efficiency ratio (PER) of fish fed the CGM80 and CGM100 diets was significantly lower than those of all other treatments (P < 0.05). Total ammonia‐nitrogen (TAN) excretion increased with elevated dietary CGM inclusion. The viscerosomatic index (VSI) of fish fed the CGM80 and CGM100 diets were significantly higher (P < 0.05) than those of fish fed the other treatments. The crude lipid content in the final body composition of the striped catfish was elevated significantly with increasing dietary CGM levels. Fish fed the CGM80 and CGM100 diets displayed haematocrit levels significantly lower (P < 0.05) than those fed the other diets. The haemoglobin content in fish was significantly higher in fish fed CGM20 and lower at CGM100 compared to fish fed the FM diet. The results of the present trial indicated that the optimum level of FM protein replacement with CGM determined by quadratic regression analysis was 25.1% on the basis of maximum SGR.  相似文献   

6.
Abstract.— The effects of phytic acid on growth, protein efficiency, feed conversion, and carcass composition of mrigal Cirrhinus mrigala fry (2.5–3.5 cm) reared indoors at 18–22 C in 70-L flow-through (1-1.5 L/min) circular tanks were examined. Fish were fed isonitrogenous (40% crude protein) and isocaloric (4.32 kcal/g) purified test diets in the form of moist cake containing different levels (0.5, 1.0, 1.5, 2.0 and 2.5%) of phytic acid (dodecasodiurn salt) at a rate of 4% body weight twice daily (0800 and 1600 h). The highest weight gain (94.87%). specific growth rate (133%). protein efficiency ratio (2.02), and best feed conversion ratio (1.21) were observed in fish fed the control diet containing no phytic acid. Live weight gain and specific growth rate were significantly reduced by dietary phytic acid inclusion above 1%. Dietary inclusion of phytic acid markedly influenced the carcass composition of the fish. Whole body crude protein and fat content declined significantly ( P < 0.05) in fish fed diets containing phytic acid, while percentage of moisture and ash in these fish was significantly ( P ≤ 0.05) higher than fish in control diets.  相似文献   

7.
A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.  相似文献   

8.
The present study examines the effect of four semi‐purified diets (casein–gelatin based) where the source of fatty acids was free (esterified) oleic acid and linoleic acid (LA) (LOA diet), linseed and olive oil (predominantly LA and linolenic acid) (LO diet), cod liver oil (rich in highly unsaturated fatty acids) (CLO diet), and soybean lecithin (phospholipids; mostly LA) (LE diet) on the growth of juvenile South American catfish (surubim, Pseudoplatystoma fasciatum, Pimelodidae) (0.98 ± 0.04 g individual weight). Fish were fed at a restricted–readjusted feeding rate for 8 wk. At the end of the experiment, LE‐diet‐fed fish grew significantly larger than those of the other three groups (P < 0.05). Considerable cannibalism was observed in all the treatments. It is suggested that the quantitative growth performance may possibly change under other conditions, with less or no cannibalism. Survival did not differ significantly among the fish fed four different diets. Muscle and liver lipid contents did not vary among dietary treatments (P > 0.05), but whole‐body lipid concentrations were affected by dietary treatments. Fish fed LE diet contained significantly lower lipid level than those fed three other diets (P < 0.05). Muscle and liver fatty acid profiles reflected dietary fatty acid composition. Arachidonic acid level was significantly higher in muscle and liver of fish fed LOA and LE diets than in those fed LO and CLO diets. The results suggest that the efficiency of elongation and desaturation of 18C fatty acids depends on the dietary lipid source, and South American catfish has considerable capacity to transform linoleate to arachidonate.  相似文献   

9.
A feeding trial was performed to determine the effect of a commercial source of Yucca schidigera and Quillaja saponaria extracts (Nutrafito Plus®), in practical diets, on striped catfish Pangasianodon hypophthalmus growth, feed utilization, body composition, total ammonia‐nitrogen (TAN) excretion and haematological parameters. Four experimental diets were supplemented with Nutrafito Plus® at 0%, 0.01%, 0.02% and 0.03% (diets: control, N01, N02 and N03 respectively). Three replicate groups of striped catfish, with initial mean weight of 1.78 ± 0.05 g, were fed one of the four diets for 12 weeks. The specific growth rate (SGR) and final weight of fish fed diet N03 was significantly higher (P < 0.05) than fish fed the other dietary treatments. The growth performance of fish fed diets N01 and N02 were not significantly different compared to fish fed the control diet. Striped catfish fed diet N03 had improved feed conversion ratio (FCR), net protein utilization (NPU) and protein efficiency ratio (PER) than the control (P < 0.05). The inclusion of the high dietary level of Yucca schidigera and Quillaja saponaria, diet N03, reduced TAN compared to all groups. Dietary inclusion of Yucca schidigera and Quillaja saponaria at all levels investigated did not affect the whole body proximate composition of the striped catfish (P > 0.05). The packed cell volume (PCV) and haemoglobin level in fish fed diet N03 was significantly higher than in the fish fed the control diet. The present study demonstrates that dietary inclusion of Yucca schidigera and Quillaja saponaria induced positive effects on growth performance and haematological parameters and decreased TAN excretion in striped catfish.  相似文献   

10.
为研究饲料中添加氧化鱼油对黄颡鱼幼鱼肠道免疫、抗氧化和其他功能指标、组织结构的影响及添加精氨酸对其的干预作用,采用2×3设计方式,在饲料中分别添加新鲜鱼油(FF)∶氧化鱼油(OF)按照(m/m)2.5∶0、1.5∶1.0和0.5∶2.0的比例配制3种基础饲料(FF,OF1,OF2),在基础饲料中分别添加0.48%精氨酸(Arg)盐酸盐配制3种精氨酸饲料(FFA,OFA1,OFA2),选取初始体质量为(4.41±0.05)g的黄颡鱼600尾,随机分为6组,每组4个重复,分别投喂6种实验饲料,饲养56 d。结果显示,在OF2组中,黄颡鱼肠道酸性磷酸酶(ACP)、碱性磷酸酶(AKP)活性和白细胞介素-6(IL-6)含量显著升高;与OF2组相比,OFA2组AKP活性和IL-6含量均显著下降。在FF、OF1、OF2三组中,肠道超氧化物歧化酶(SOD)活性呈下降趋势,谷胱甘肽过氧化物酶(GSH-PX)和过氧化氢酶(CAT)活性呈现上升趋势,总抗氧化能力(T-AOC)呈现先下降后上升的趋势,但差异均不显著;在OF2组中,丙二醛(MDA)含量显著升高;添加精氨酸后,除SOD活性有显著升高外,其他抗氧化指标的组间均无显著性差异。双因素方差分析显示,精氨酸对黄颡鱼肠道CAT活性的影响达到显著水平,饲料中氧化鱼油和精氨酸对黄颡鱼肠道GSH-PX活性的影响存在交互作用。在FF、OF1、OF2三组中,肠道二胺氧化酶(DAO)活性呈现下降趋势,一氧化氮合酶(i NOS)活性呈现上升趋势,但差异均不显著;与OF2组相比,OFA2组的DAO和i NOS活性分别显著升高和下降;双因素方差分析显示,精氨酸(Arg)对黄颡鱼肠道DAO、i NOS活性的影响分别达到显著水平。在OF1组中,肠道皱壁高度、肌层厚度和杯状细胞数量均明显升高;与OF2组相比,OFA2组皱壁高度和杯状细胞数量明显升高;与FF组相比,FFA组肌层厚度明显增加。双因素方差分析显示,氧化鱼油对黄颡鱼肠道皱壁高度的影响达到显著水平。研究表明,在饲料中添加一定水平的氧化鱼油会抑制黄颡鱼幼鱼肠道免疫及抗氧化指标,损伤肠道组织结构,但添加一定量的精氨酸可以缓解氧化鱼油对黄颡鱼幼鱼肠道免疫、抗氧化和组织结构的抑制作用。  相似文献   

11.
A 20‐week feeding trial was conducted to measure growth, nutrient utilization and faecal/gut bacterial counts in triplicate groups of red hybrid tilapia, Oreochromis sp., when fed diets supplemented with 0.5% organic acids blend (OAB), 1.0% OAB, 0.5% oxytetracycline (OTC) or a control diet (no additives). At the end of the feeding trial, tilapia were challenged with Streptococcus agalactiae for 22 days. Fish fed the OTC diet had significantly higher (P < 0.05) growth than the control treatment, while growth between fish fed the OTC or OAB diets was not significantly different (P > 0.05). Phosphorus, dry matter and ash digestibility were significantly higher in the 1.0% OAB diet than the control diet. Fish fed the OAB diets had significantly lower colony‐forming units of adherent gut bacteria compared to the control or OTC treatments while those fed the 1.0% OAB diet had the lowest total faecal bacterial counts. Tilapia fed the 0.5% OTC or OAB diet had significantly higher resistance to S. agalactiae than those fed the control diet. This study indicates that dietary organic acids can potentially replace OTC as a growth promoter and antimicrobial in tilapia feeds.  相似文献   

12.
Two experiments were conducted to investigate the effect of dietary taurine and cystine on growth and body composition of juvenile red sea bream Pagrus major. In Experiment I, a casein-based semi-purified diet included a small amount of fish meal were supplemented with taurine at the levels of 0 (control) and 1.0%. The experimental diets in Experiment II were without fishmeal and supplemented with taurine at 0 (control), 0.5, 1.0 and 2.0% or cystine at 1.0 and 2.0%. These diets were fed three times a day for 6 weeks to fish (average body weight: 2.3 g in Experiment I and 2.5 g in Experiment II). In Experiment I, fish fed the taurine-supplemented diet showed significantly (P < 0.05) improved growth, feed efficiency and feed consumption relative to fish fed the unsupplemental diet. The whole body taurine content increased, whereas the non-essential amino acid contents decreased, in fish fed the taurine-supplemental diet compared to fish fed the unsupplemented diet. In Experiment II, the growth, feed efficiency and feed consumption of fish fed the taurine-supplemented diets, irrespective of the dietary taurine levels, were significantly higher than those of fish fed the control diet and the cystine-supplemented diets. Taurine content in the whole body increased with the dietary taurine level, while the taurine contents did not increase by the supplemental cystine. Other free amino acid contents in the taurine-supplemented diet groups followed similar trends to those in Experiment I. These results indicate that supplemental taurine to a casein-based semi-purified diet at more than 0.5% improved the growth and feed performance of juvenile red sea bream. It is also suggested that juvenile red sea bream cannot metabolize cystine into taurine.  相似文献   

13.
A nutrition trial with meagre, Argyrosomus regius was assessed to determine the effect of dietary replacement of fish oil (FO) by soybean oil (SO) on the growth, feed utilization, body composition, fatty acid composition and basic haematological parameters. Six isonitrogenous (47% crude protein) and isoenergetic (gross energy 22 kJ/g) experimental diets were formulated by replacing 0 (FO), 20 (S20), 40 (S40), 60 (S60), 80 (S80) and 100 (S100) % of the FO with SO. Fish were fed three times daily to near satiation for 14 weeks. The specific growth rate (SGR) of fish fed S100 diet was significantly lower than the other treatments, except SO80 diet. The fish fed SO100 diet displayed significantly higher feed conversion ratio than that of other diets (P < 0.05). It was observed that fish fed the SO100 and SO80 diets displayed haemoglobin (HGB) levels significantly lower (P < 0.05) than fish fed the SO20 diet. Packed cell volume (PCV) of fish fed SO20 diet was significantly higher compared to SO100. The white blood cell (WBC) and red blood cell (RBC) remained unaffected by dietary treatment. The docosahexaenoic acid (22:6n‐3, DHA) and eicosapentaenoic acid (20:5n‐3, EPA) levels of meagre were significantly reduced by the substituting of dietary SO by FO at the end of the feeding period. The level of linoleic acid (18:2n‐6, LA) and linolenic acid (18:3n‐3, LNA) significantly raised in fish fed with SO diets (P < 0.05). The results of this study showed that SO could be replaced FO up to 80% in meagre diet without negative effect on growth performance and basic haematological parameters. Furthermore, the maximum level of FO replacement with SO determined by second order polynomial regression analysis, was 30.1% on the basis of maximum SGR.  相似文献   

14.
The influence of dietary supplementation of Lactobacillus acidophilus, on growth performance, digestive enzyme activities, gut histomorphology and gut microflora were evaluated in juveniles striped catfish (Pangasianodon hypophthalmus). Five experimental diets were formulated by supplementing 0, 103, 105, 107 and 109 CFU/g L. acidophilus in fishmeal and casein‐based semi‐purified diet. Triplicate groups of striped catfish (21.69 ± 0.18 g) were stocked in 15 fiberglass tanks with stocking density of 25 individuals per tank and fed twice daily at 2.5% of the fish body weight for 12 weeks. Weight gain, specific growth rate, feed conversion ratio and the protein efficiency ratio were significantly higher in fish fed with 105 and 107CFU/g L. acidophilussupplemented diets compared with the other treatment groups. Compared with the control and fish fed low (103 CFU/g) L. acidophilus supplementation, those fed with 105 and 107 CFU/g had significantly higher (p < 0.05) apparent protein digestibility. Inclusion of L. acidophilus at 107 CFU/g diet significantly increased amylase, protease and lipase activities. Microscopic analysis showed that the villi length in both the anterior and posterior gut and microvilli length in the posterior gut increased significantly in fish fed L. acidophilus supplementation at 105 and 107 CFU/g of diet. The fish fed L. acidophilus supplemented diets significantly increased the total lactic acid bacteria counts in the gut of striped catfish compared with the control‐fed group. Based on gut histomorphology and growth performance, inclusion of L. acidophilus at 105 CFU/g appears to have the most positive effect on striped catfish farming.  相似文献   

15.
We evaluated the effect of different concentrations of 5′‐inosine monophosphate (IMP) and 5′‐guanosine monophosphate (GMP) on the growth, immunity and muscle composition of turbot Scophthalmus maximus. Eight diets (containing no IMP or GMP, or 0.5 g/kg IMP, 1.0 g/kg IMP, 2.0 g/kg IMP, 0.5 g/kg GMP, 1.0 g/kg GMP, 2.0 g/kg GMP, or 0.5 g/kg IMP plus 0.5 g/kg GMP) were prepared. A total of 360 fish (average body weight of 105 g) were randomly selected and placed in groups into 24 plastic aquaria (8 treatments × 3 replicates × 15 individuals per plastic aquaria). The tanks were maintained at the temperature of 15 ± 2°C. The experimental diets were fed for 60 days. The specific growth rate (SGR) was significantly higher in S. maximus fed with IMP or GMP compared with fish fed neither IMP nor GMP. The highest SGR was observed in fish fed with 1.0 g/kg IMP. Supplementation with these dietary nucleotides had a positive, but not significant effect on the activity of superoxide dismutase, alkaline phosphatase and acid phosphatase. There was a significant difference in the moisture and crude lipid content of muscle from S. maximus fed the different diets compared with control fish. The highest moisture content was 83.44 for a diet of 0.5 g/kg IMP plus 0.5 g/kg GMP, which was also significantly higher when compared to fish fed alternative diets. The crude lipid content of S. maximus fed diets containing either IMP or GMP was significantly higher than those fed diets without IMP or GMP. Thus, according to these results, the optimal level of dietary IMP is 1.0 g/kg, which correlates with the largest increase in growth performance of S. maximus.  相似文献   

16.
A feeding trial with striped catfish, Pangasianodon hypophthalmus was performed to determine the effect of Yucca schidigera in practical diet on the growth, feed utilization, body composition, total ammonia–nitrogen (TAN) excretion and haematological parameters. A diet with fish meal as the main protein source without yucca extract was used as the control diet (Diet 1). Four diets were formulated with 0.075 (Diet 2), 0.1 (Diet 3) and 0.15 (Diet 4)% of yucca extract respectively. Fifteen fish per tank (initial mean weight 1.78 ± 0.05 g) were randomly allocated to 15 fibreglass tanks (80‐L) connected to a freshwater closed recirculation system (temperature 29.7 ± 1.0°C). The experimental diets were tested in triplicates for 12 weeks. The specific growth rate of fish fed Diet 4 was significantly higher when compared with fish fed Diet 1. The growth of fish fed diets Diet 2 and Diet 3 were not significantly different compared with fish fed the Diet 1. Striped catfish fed Diet 4 had significantly lower feed conversion ratio compared with fish fed Diet 1 and Diet 2 (P < 0.05).The incorporation of high level Yucca schidigera extract in the diets reduced TAN compared with Diet 1. Dietary inclusion of Yucca extract levels did not significantly affect the biometric parameters or whole body proximate composition of the striped catfish (P > 0.05). The PCV (%) in fish significantly increased with high levels of Yucca inclusion (Diet 4) compared with control diet. Fish fed Diet 4 showed significantly higher haemoglobin levels than Diet 1 (P < 0.05). The results indicate that dietary inclusion of Yucca schidigera extract is promising as a feed additive that could improve growth performance and some haematological parameters and the best Yucca schidigera level was 0.15%.  相似文献   

17.
Nile tilapia juveniles (8.35 ± 0.80 g) were fed on four levels (0.0%; 0.5%; 1.0%; 2.0%, 4.0%) of Aurantiochytrium sp. meal (ALL‐G‐RICH?), a source of docosahexaenoic acid (DHA). The 1% Aurantiochytrium sp. meal diet was compared to a control diet, which contained the same amount of DHA as cod liver oil (CLO) at 1.7% diet. Groups of 25 fish were stocked in 100 L tanks and fed twice daily until apparent satiation, for 57 days, at 28°C. Increasing dietary Aurantiochytrium sp. meal reduced the body retention of DHA and n‐3 polyunsaturated fatty acids (n‐3 PUFA) but increased the body retention of alpha‐linolenic (α‐LNA), linoleic (LOA) and n‐6 polyunsaturated fatty acids (n‐6 PUFA). Fatty acid profile in tilapia muscle was affected by increasing dietary inclusions of Aurantiochytrium sp. meal, with an increase in DHA, α‐LNA, n‐3 PUFA and n‐3 long chain‐polyunsaturated fatty acids (n‐3 LC‐PUFA) but a decrease in monounsaturated fatty acids (MUFA), n‐6 PUFA and n‐6 long‐chain polyunsaturated fatty acids (n‐6 LC‐PUFA). There was a larger body retention of DHA, α‐LNA, LOA, n‐3 PUFA and n‐6 PUFA fatty acids and a higher percentage of DHA, n‐3 PUFA and n‐3 LC‐PUFA in muscle fatty acid profile in fish fed on CLO diets than in those fed on 1% Aurantiochytrium sp. Therefore, Aurantiochytrium sp. meal is an alternative source of DHA for Nile tilapia diets.  相似文献   

18.
Growth performance, immune responses and disease resistance were studied in juvenile channel catfish, Ictalurus punctatus, fed a commercial diet (35.3% crude protein and 5.6% lipid) supplemented with menhaden fish oil at levels of 0, 3, 6, and 9% for 15 wk. Dietary fish oil levels did not significantly influence growth performance of catfish. Fatty acid compositions of whole‐body and liver reflected dietary fatty acid composition. No differences were found in hematological values, except that fish fed the 9% fish oil diet had significantly lower hematocrit. The resistance of erythrocytes to hemolysis in hypotonic solutions increased with increasing fish oil levels and the highest resistance was seen with the 9% fish oil diet. Fish fed 6 and 9% added fish oil diets had significantly higher serum protein levels than that of control fish. Serum lysozyme activity of fish fed 3 and 6% added fish oil diet was significantly higher than that of the control. Complement activity and chemotaxis ratio significantly decreased in fish fed diets with 6 or 9% added fish oil. The 3% added fish oil diet, however, had significantly highest natural hemolytic complement activity. Mortality from Edwardsiella ictaluri 14 d postchallenge and antibody titers to E. ictaluri did not differ among treatments.  相似文献   

19.
This study evaluated the effects of dietary Aloe vera polysaccharides on growth performance, feed utilization, hemato-biochemical parameters, and resistance against low water pH in African catfish (Clarias gariepinus) fingerlings. Fish were divided into five triplicate groups before being fed feeds supplemented with 0% (control), 0.5%, 1.0%, 2.0%, and 4.0% A. vera/kg diet for 8 weeks. Fish fed 1.0% A. vera/kg diet had significantly increased (P < 0.05) growth parameters (i.e., final weight, weight gain, absolute growth rate, and specific growth rate) compared to unsupplemented ones. Among dietary groups, significantly lower feed conversion ratio was presented in fish fed 1.0% followed by those fed 0.5, 2.0%, and 4.0% A. vera/kg diet (P < 0.05). The protein efficiency ratio was significantly higher (P < 0.05) in fish fed 1.0% A. vera/kg diet compared to unsupplemented fish and those fed 4.0% A. vera/kg diet, respectively. Dietary A. vera polysaccharide crude extracts requirement suitable for growth and feed utilization was estimated to be between 1.76 and 1.79% A. vera/kg diet. Overall, A. vera extracts had improved hemato-biochemical indices when compared to unsupplemented fish, and decreased some of the indices, especially at high dietary inclusion level (4%/kg diet). Furthermore, A. vera-supplemented fish had higher survival probability throughout the low water pH challenge period, except those fed 4% A. vera/kg diet and control diet.  相似文献   

20.
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   

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