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1.
ABSTRACT:   The effect of taurine on growth of yellowtail juveniles Seriola quinqueradiata was investigated by a feeding experiment of diets containing various taurine levels. Test diets supplemented with 0, 0.5, 1.0, 1.5 and 2.0% of taurine were prepared. These diets were fed to yellowtail juveniles with an initial mean body weight of 0.5 g for 6 weeks. Supplementation of taurine in the diet of yellowtail improved their growth performance significantly ( P  < 0.05) over the initial 3-week period. The fish fed with the taurine-supplemented diet improved in percent gain and feed efficiency over both 3 and 6 weeks. Taurine content in the muscle proportionally increased with the dietary taurine level. The fish fed without supplemented taurine diet showed higher contents of serine in the muscle. With each increase in the inclusion level of taurine content in the diet, the concentration of serine in the muscle decreased. The cystathionine content in the muscle of each group was unchanged. These results suggest that taurine supplementation in the diet not only improves growth but also affects the sulfur amino acid metabolism of yellowtail juveniles.  相似文献   

2.
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   

3.
ABSTRACT:   To elucidate the hemolytic suppression roles of taurine and the necessity of dietary taurine supplementation in yellowtail Seriola quinqueradiata fed a diet without fishmeal, juvenile fish with an initial body weight of 250 g were fed for 40 weeks in floating net cages on soybean protein diets supplemented with 0, 3.0, 4.5 and 6.0% taurine. Taurine concentration of the experimental diets were 0.03, 33.9, 52.8 and 71.6 mg/g, respectively. On the 21st week, fish fed the taurine unsupplemented diet had inferior growth and feed performances, higher death, and there were incidences of green liver and hemolytic anemia. In this group, hepatic and plasma taurine concentrations, serum osmolality and osmotic tolerance of erythrocytes (EC50 value) were significantly lower, and plasma hydroperoxide concentration was markedly higher than in the taurine supplemented groups. These conditions markedly improved corresponding with the increase of dietary taurine concentration. These results indicate that taurine plays a role in hemolytic suppression through osmoregulation and biomembrane stabilization in fish. In addition, it is suggested that yellowtail requires dietary taurine as an essential nutrition for maintaining physiological condition normally.  相似文献   

4.
以平均体重为(8.13±0.05)g的鲈鱼(Lateolabrax japonicus)幼鱼为研究对象,探讨了在低鱼粉饲料中添加牛磺酸、蛋氨酸和半胱氨酸对鲈鱼幼鱼生长及鱼体氨基酸组成的影响.分别在基础饲料中添加0(对照组T-0)、1.0％牛磺酸(T-1)、2.0％牛磺酸(T-2)、0.5％蛋氨酸(M-0.5)和0.5％半胱氨酸(C-0.5)制成5种等氮等脂的实验饲料,在室内流水养殖系统中进行为期70 d的养殖实验.结果显示,T-1、T-2、M-0.5和C-0.5组鲈鱼幼鱼的终末体重、特定生长率(SGR)、增重率(WGR)和摄食率(FI)均显著高于T-0组(P＜0.05);饲料中添加牛磺酸、蛋氨酸和半胱氨酸均可提高鱼体粗蛋白和粗脂肪含量(P＜0.05),鱼体水分含量则呈现出相反的变化趋势;T-I、T-2组肝脏、肌肉中的牛磺酸含量显著高于T-0组(P＜0.05),但M-0.5、C-0.5组肝脏、肌肉中牛磺酸含量与T-0组无显著差异(P＞0.05);T-1、T-2和C-0.5组肝脏的必需氨基酸及总氨基酸含量均高于T-0组(P＜0.05),但M-0.5组肝脏必需氨基酸及总氨基酸含量与T-0组无显著差异(P＞0.05);T-1、T-2、M-0.5和C-0.5组肌肉的必需氨基酸含量均高于T-0组,但只有M-0.5组显著高于T-0组(P＜0.05);T-1、T-2和M-0.5组肌肉的总氨基酸含量高于T-0组(P＜0.05),C-0.5组与T-0组无显著差异(P＞0.05).研究表明,饲料中添加牛磺酸、蛋氨酸和半胱氨酸均可提高鲈鱼幼鱼的生长,同时可以改善鲈鱼肝脏和肌肉中的氨基酸沉积.  相似文献   

5.
The effect of increasing levels of dietary phospholipids (PL) on the ovarian development and reproductive performance of Chinese mitten crab Eriocheir sinensis were investigated using four semipurified formulated diets supplemented with 0%, 1.2%, 2.4%, and 3.6% PL. Four groups of 40 females, with an average individual body weight of 95–120 g, were fed the experimental diets for a period of 7 months. Male crabs were introduced into the female rearing system in March, and mating, spawning, and egg hatching occurred in the following month. After 10 weeks of feeding, females fed the diet with 2.4% PL had a significantly higher gonadosomatic index (GSI) than females fed the diet with 0% PL, whereas females fed the diet with 1.2% PL had a significantly higher hepatic moisture content and lower hepatic lipid content than the other groups (P < 0.05). After mating, the spawning rate was higher among females fed diets with 3.6% and 2.4% PL (95% and 92%, respectively) compared with females fed diets with 0% and 1.2% PL (both 81%). The results showed that egg production (total number of eggs/female) and fecundity increased with increasing dietary PL level, with females fed diets with 0% and 1.2% PL supplementation having significantly lower values than females fed the diet with 3.6% PL (P < 0.05). In conclusion, our results suggest that dietary PL supplementation has a positive effect on ovarian development and reproductive performance of E. sinensis broodstock. Further study should aim to investigate the optimal PL level in the broodstock diet of E. sinensis in respect to offspring quality.  相似文献   

6.
The requirement of dietary taurine in yellowtail fed a non-fish meal (FM) diet based on soy protein concentrate (SPC) was examined by a feeding trial. A recovery test (RCT) was also conducted to confirm the requirement of dietary taurine in yellowtail fed the SPC diet. The non-FM diet including 58% SPC as the protein source was supplemented with 0% (NTS) and 4.5% taurine (TS). A diet including 58% FM was also included as a reference. Juvenile fish (initial BW; 470 g) were fed one type of experimental diet for 39 weeks. The RCT group was fed the taurine un-supplemented SPC (NTS) diet for the first 23 weeks, and then fed the taurine supplemented SPC (TS) diet for 16 weeks. Tissue taurine concentration of the NTS group was significantly lower (P < 0.05) than that of the FM group. Specific growth rate (SGR) and feed conversion ratio (FCR) of the NTS group was significantly inferior compared to the FM group. In the NTS group, green liver syndrome was observed in all the samples. In contrast, tissue taurine concentration of the TS group increased to a similar level to that of the FM group. Compared to the NTS group, SGR and FCR of the TS group were significantly improved (P < 0.05) by taurine supplementation to the SPC diet. Moreover, yellowtail of this group could be reared for a long term without any physiological abnormalities, and their physiological condition and performance were comparable to the fish fed the FM diet. Although the physiological condition and performance of the RCT group was markedly inferior as the NTS group at the 23rd week (wk23) of the feeding trial, the physiological condition and performance of the RCT group markedly improved by the switch of the NTS diet to the TS diet at the end of feeding trial on the 39th week (wk39). These results indicate that yellowtail fed a non-FM diet based on SPC require taurine as an essential nutrient for maintaining normal physiological condition and growth performance.  相似文献   

7.
The necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance of red sea bream Pagrus major fed nonfishmeal (non-FM) diets was investigated. Yearling red sea bream (initial body weight, 580 g) were fed for 36 weeks on non-FM diets based on soy protein concentrate (SPC) supplemented with taurine at levels of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. Specific growth rate (SGR) and feed conversion ratio (FCR) of fish fed the taurine-unsupplemented SPC diet were markedly inferior. In these fish, incidence of green liver was markedly higher and was accompanied by a decrease of tissue taurine concentration and an increase of hepatopancreatic bile pigment content. The green liver symptom was mainly caused by an increase of hemolysis since the erythrocytes became osmotically fragile due to taurine deficiency. Physiological abnormality and growth performance (SGR and FCR) were markedly improved by taurine supplementation to the SPC diets. These results indicate that dietary taurine supplementation is necessary for yearling red sea bream fed non-FM diet based on SPC to maintain normal physiological condition and growth performance.  相似文献   

8.
This study was conducted to investigate the effect of dietary taurine levels on growth and feeding behavior of juvenile Japanese flounder. Three different taurine level diets were prepared by supplementation of taurine (T-0%, 0.5% and 1.5%) to the basal diet. Fish meal washed with 70% ethanol to remove taurine was used as the sole protein source. Feeding experiments were carried out twice at 20 °C by using different size of fish (average body weight: 0.3 g in Experiment I and 3.7 g in Experiment II). The feeding behavior of fish was observed throughout the experimental period. At the end of experiments, fish were killed for amino acids analysis.

The final average body weight and feed efficiency of juvenile Japanese flounder fed the T-1.5% diet was significantly higher than those of fish fed the T-0% diet in Experiments I and II. Abnormal feeding behavior such as multiple feeding while swimming in the water column was observed in the T-0% group in Experiment I. These findings indicate that taurine is essential for normal growth and development of normal feeding behavior of juvenile Japanese flounder.  相似文献   


9.
为探讨饲料牛磺酸含量对斜带石斑鱼幼鱼生长性能、体成分、TauT mRNA表达量及牛磺酸合成关键酶(CSD和CDO)活性的影响,实验在以酪蛋白和明胶为蛋白源的基础饲料(0DT)中分别添加0.5%(0.5DT)、1.0%(1.0DT)、1.5%(1.5DT)的牛磺酸,配制成4种不同牛磺酸含量的饲料。将平均体质量为(13.85±0.25) g的320尾斜带石斑鱼幼鱼随机分为4组,每组4个循环水族箱,每箱放养20尾鱼,每组分别投喂一种相同实验饲料,每天定时投喂实验饲料至表观饱食状态,实验为期84 d。结果显示,在0DT饲料中补充外源牛磺酸能显著提高饲料效率、摄食率、增重率和全鱼粗蛋白含量,而显著降低肝体比和全鱼粗脂肪含量。组织中肝脏、肌肉、肠道TauT mRNA表达量在1.0DT组时达到最大值,且显著高于其他各组,当饲料牛磺酸含量继续增加至1.5DT组时明显降低,但仍显著高于0DT和1.0DT组。斜带石斑鱼幼鱼血浆、肝脏、肠道和肌肉中牛磺酸含量与饲料牛磺酸含量之间呈正相关。饲料中补充外源牛磺酸能够显著降低肝脏、肌肉中CSD活性,同时降低血浆、肝脏、肠道和肌肉中CDO活性,但对血浆CSD活性无显著影响。研究表明,饲料中补充外源牛磺酸能够明显促进斜带石斑鱼幼鱼生长,增加鱼体蛋白沉积,同时降低鱼体脂肪沉积,上调组织中TauT mRNA表达水平及提高牛磺酸蓄积,降低牛磺酸合成关键酶活性。研究表明,以增重率为目标,通过二次多项式回归分析,饲料中牛磺酸的适宜含量为0.92%。  相似文献   

10.
The requirement for taurine in juvenile Japanese flounder Paralichthys olivaceus was determined by feeding diets containing various levels of taurine and cystine. Test diets supplemented with 0.5, 1.0 and 1.5% of taurine or with 0.5, 1.0 and 1.5% of L -cystine were prepared. The basal diet contained 55% protein from white fish meal. These diets were fed to juvenile Japanese flounder with an initial mean bodyweight of 0.9 g (total length (TL) 48 mm) for 5 weeks. Approximately 1.4% taurine content in the diet was required for optimum growth of juvenile flounder. A positive linear relationship was noted between the content of taurine accumulated in the muscle, liver and brain and the level of taurine in the diet. However, there was no increased taurine content in tissues of fish fed the cystine-supplemented diet. In contrast, the fish fed control and cystine-supplemented diets showed higher contents of cystathionine in the tissues. The concentration of cystathionine in tissues rapidly decreased with an increase of taurine in the diet. It was also observed that for each of the dietary groups, a trace amount of taurine was excreted. These results suggest that the taurine content in the diet affects the sulfur amino acid metabolism of juvenile Japanese flounder, and indicate that juvenile flounder are unable to biosynthesize taurine from cystine.  相似文献   

11.
研究了牛磺酸对半滑舌鳎(Cynoglossus semilaevis Günther)亲鱼繁殖性能、抗氧化功能、卵子及仔鱼质量的影响。在基础饲料中分别添加0、0.5%、1.5%的牛磺酸,配制3组(对照组T-0、T-0.5、T-1.5)等氮等脂的配合饲料,在室内流水养殖系统进行为期63 d的养殖实验。研究结果显示,在饲料中添加0.5%牛磺酸,不仅能够提高半滑舌鳎亲鱼的相对产卵量,还能促进亲鱼体内睾酮和雌二醇的分泌(P<0.05);T-0.5组浮卵率、受精率、孵化率、卵径、油球直径、3日龄、7日龄仔鱼体长均显著高于对照组(P<0.05),T-0.5组和T-1.5组仔鱼畸形率显著低于对照组(P<0.05);3个实验组仔鱼生存活力指数(SAI)无显著性差异(P>0.05);饲料中添加牛磺酸能够提高其肝脏和性腺中牛磺酸含量,降低肝脏中半胱胺双加氧酶活性;T-0.5组肝脏、血清、精巢、精液中超氧化物歧化酶(SOD)活性显著高于对照组(P<0.05),性腺和卵子中丙二醛(MDA)含量显著低于对照组(P<0.05)。研究结果表明,饲料中添加牛磺酸能够提高半滑舌鳎亲鱼繁殖性能、抗氧化功能、卵子及仔鱼质量。在本研究条件下,牛磺酸含量为0.5%的饲料组为最佳饲料组。  相似文献   

12.
ABSTRACT:   The effect of dietary taurine on juvenile Japanese flounder was determined by feeding three taurine-supplemented experimental diets (TAU) and a commercial diet (CD) to evaluate a practical diet for juvenile Japanese flounder. Juvenile Japanese flounder were reared on the three experimental diets supplemented with taurine at 0, 0.5, 1.0% and CD. These diets were fed to juvenile Japanese flounder of an initial mean body weight of 0.2 g for 6 weeks at 20°C and the taurine contents of the whole body and tissues were analyzed. The final average body weight of juvenile Japanese flounder fed the 1.0% TAU was significantly higher than that of the other groups. Taurine contents in the whole body and tissues increased with the increase in dietary taurine level. These results indicate that juvenile Japanese flounder require at least 15 mg/g taurine in the diet, even though a combined mix of fish, krill and squid meal was the main protein source in the experimental diets.  相似文献   

13.
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   

14.
This study was conducted to investigate the mechanism of green liver symptom induction and the effect of dietary taurine supplementation on growth performance in juvenile red sea bream fed non-fishmeal diets based on soy protein concentrate (SPC). Juvenile fish (initial BW 72 g) were fed for 20 weeks on SPC diets supplemented with taurine at levels of 0, 1.0, and 2.0%. In the taurine-unsupplemented SPC diet group, specific growth rate (SGR) and feed conversion ratio (FCR) were significantly inferior (P < 0.001), and incidence of green liver was observed in 70% of fish. In this group, hepatopancreatic and plasma taurine concentrations were lowest (P < 0.05), hepatopancreatic content of bile pigments was highest (P < 0.05), and osmotic tolerance of erythrocytes was inferior (P < 0.05) among the dietary treatment groups. Serum osmolality of all treatment groups was at similar levels. These physiological abnormalities as well as SGR and FCR were improved by dietary taurine supplementation. These results indicate that the mechanism for induction of green liver symptom is bile pigment overproduction due to increased hemolysis because erythrocytes become osmotically fragile due to dietary taurine deficiency. Taurine supplementation of SPC diets is essential for maintaining normal physiological condition and growth performance in juvenile red sea bream.  相似文献   

15.
Three trials were run to identify the limiting dietary amino acids in practical, soy‐based formulations for California yellowtail juveniles. In the first trial, four diets were formulated with 20% fish meal and 43% soy protein concentrate. The basal diet was supplemented with methionine, lysine, and taurine (MLT), and each supplement was then individually deleted in three additional diets (LT, MT, and ML). A significant decrease in growth was only seen in fish fed the ML diet. The second and third trials were designed to test graded levels of dietary taurine and methionine, respectively. Dietary taurine ranged from 0.32 to 1.5%, and methionine levels ranged from 0.95 to 1.19% of the diet with constant levels of cysteine (0.73%). While weight gains were considered adequate to detect a dietary amino acid deficiency, there was no significant effect of graded levels of either taurine or methionine on final weights, growth rates, survival, or feed efficiency. In conclusion, the practical diets tested required taurine supplementations, but did not require lysine or methionine supplementation. While these data are insufficient to determine the taurine or methionine requirement of California yellowtail, it provides minimum levels likely to meet these requirements. Additional research is necessary to determine taurine and methionine requirements precisely in this species.  相似文献   

16.
ABSTRACT:   This study was conducted to investigate the effect of dietary taurine and cholyltaurine (C-tau) on growth and body composition of juvenile red sea bream Pagrus major . Semi-purified casein-based diets supplemented with 0 (control diet), 0.1, 0.3, 0.5 and 0.7% taurine and 0.5% C-tau were fed to red sea bream (average body weight 4.7 g) for 6 weeks at 20°C. The growth and feed efficiency were the lowest in fish fed the control diet. Taurine supplementation improved the growth and feed efficiency of fish dose-dependently, and the taurine requirement was estimated as 0.52% in terms of optimizing growth and 0.48% in terms of optimizing feed efficiency. Taurine content in the whole body and liver increased with the dietary taurine level. Supplemental C-tau at the 0.5% level had limited effects on the growth and no effect on body taurine, biliary bile salt and liver fat contents. From these results it can be inferred that the optimal dietary taurine requirement of juvenile red sea bream is 0.5% on a dry weight basis, and that the supplementation of taurine in the diet not only improves the growth but also increases hepatic lipid levels of red sea bream juveniles.  相似文献   

17.
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   

18.
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   

19.
Experimental diets were formulated containing six levels of linolenic acid (0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%) and each diet was fed to darkbarbel catfish Pelteobagrus vachelli in triplicate for 84 days. Weight gain, specific growth rate and feed efficiency increased with the increasing levels of dietary linolenic acid, but were not significantly different among diets containing 1.0%, 1.5%, 2.0% and 2.5% linolenic acid. Red blood cell count and haemoglobin were significantly higher in fish fed the 1.0% linolenic acid than other diets. Lysozyme activity and immunoglobulin M content in fish fed 1.0% of linolenic acid were significantly higher compared with the other diets. Antibody titre in fish fed 1.0–2.5% linolenic acids was significantly higher than in fish fed 0 or 0.5% linolenic acid 14 days after Aeromonas hydrophila challenge. This study indicates that linolenic acid is essential to darkbarbel catfish. Two‐straight broken‐line analysis with SGR showed that a dietary level of 1.29% linolenic acid is the minimum required for adequate growth of darkbarbel catfish. Considering other measured indicators of fish performance, a level of 1.0–1.5% linolenic acid in the diet is recommended for the darkbarbel catfish.  相似文献   

20.
Feeding experiment was conducted to determine whether fermentation and taurine supplementation of soybean meal (SBM) fed to yellowtail improve growth performance and lipid digestion. Six diets were formulated and designated as SBM, SBM supplemented with taurine (SBM + T), SBM fermented by Bacillus spp. (FSBM1), SBM fermented by Lactobacillus spp. (FSBM2), FSBM2 supplemented with taurine (FSBM2 + T), and fish meal (FM). Yellowtail fingerlings with an initial body weight of 42 g were stocked in 200‐L tanks. The fish were fed, each diet was fed twice daily in two separate tanks for 8 weeks. Results showed that lipid digestibility of the SBM diet was significantly lower than that of the FM diet, but SBM diet lipid digestibility was improved by taurine supplementation and fermentation. Lipase activity in anterior intestinal digesta, lipid contents in liver and muscle, and bile acid concentrations in gallbladder and anterior intestinal digesta were significantly lower in fish fed SBM diet than in fish fed FM diet; these parameters were not significantly different between fish fed SBM + T, FSBM2, FSBM2 + T diets and FM diet. Although taurine supplementation or fermentation improved lipid digestibility compared with FM diet, growth parameters were only improved in the fish fed FSBM2 + T diet, indicating that apart from a lack of taurine, SBM contains other factors responsible for inferior growth of yellowtail. These factors can be partially eliminated by Lactobacillus spp. fermentation.  相似文献   

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