草鱼幼鱼肌醇营养需要量的研究

以酪蛋白、明胶和鱼粉为蛋白源,配制含肌醇水平分别为0、50 mg/kg、100 mg/kg、200 mg/kg、400 mg/kg8、00 mg/kg、1 600 mg/kg的7组实验饲料。每组设3个重复,连续投喂体质量(4.78±0.18)g的草鱼(Ctenopharyngodon idella)幼鱼9周,通过测定生长指标、部分血清生化指标和全鱼营养成分来评价饲料肌醇添加水平对草鱼幼鱼的影响。结果表明,饲料中肌醇添加水平≥200 mg/kg使草鱼幼鱼增重率(WGR)、特定生长率、血清中总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)含量与对照组相比有显著提高(P<0.05),而血清甘油三酯(TG)含量比对照组有显著降低(P<0.05);200 mg/kg和400 mg/kg肌醇添加组草鱼幼鱼饲料系数(FCR)比对照组有显著降低(P<0.05);饲料中添加肌醇对草鱼幼鱼存活率、血清中高密度脂蛋白胆固醇和全鱼营养成分无显著影响(P>0.05)。对WGR、FCR、TC、TG和LDL-C进行折线回归分析得出饲料中肌醇添加水平为166～214 mg/kg对草鱼幼鱼的生长比较适宜。     

红鱼粉型饲料中添加胆汁酸对大菱鲆生长及肝功能的影响

研究了在红鱼粉型饲料中添加胆汁酸对大菱鲆摄食、生长及肝脏功能的影响。1080尾初始体质量(19.52±0.02)g的大菱鲆随机分为4组,每组3个重复,每个重复90尾,置于12个2.4 m×1.2m×1.1m养殖缸中,投喂白鱼粉饲料、红鱼粉饲料及红鱼粉饲料中分别添加150 mg/kg和300mg/kg胆汁酸4种试验饲料。67d的养殖试验结果表明,与白鱼粉型饲料相比,红鱼粉型饲料组大菱鲆的特定生长率、肥满度、血清甘油三酯和胆固醇均显著降低(P0.05),而饲料系数和血清谷草转氨酶活性显著升高(P0.05);在红鱼粉型饲料中添加150mg/kg胆汁酸后,大菱鲆的特定生长率和肥满度均显著高于未添加胆汁酸组(P0.05);添加300mg/kg胆汁酸试验组的大菱鲆血清谷草转氨酶活性显著低于未添加胆汁酸组(P0.05)。综上所述,红鱼粉型饲料中添加150mg/kg胆汁酸能够显著提高大菱鲆的特定生长率和肥满度,添加300mg/kg胆汁酸能显著降低血清谷草转氨酶活性,起到保护大菱鲆肝脏功能的作用。     

实用饲料添加肌醇对草鱼生长、脂质代谢及抗氧化机能的影响

为探讨肌醇对草鱼生长、脂质代谢及抗氧化机能的影响,以实用饲料配方为基础,分别添加0(对照)、50、100、150、200、300和400 mg/kg肌醇,配制成7组等氮等脂的饲料,每组饲料设4个重复,每个重复饲喂初始体质量为(15.00±0.15)g的草鱼25尾,养殖56 d。结果显示,饲料中添加100~150 mg/kg肌醇能显著提高草鱼终末均重(FBW)、增重率(WGR)、特定生长率(SGR)及饲料效率(FE);随饲料肌醇添加水平的上升,全鱼脂肪、肝脏脂肪和脂肪沉积率先升后降,在50~300 mg/kg均与对照组存在显著差异,且均在100 mg/kg达到最大值。肌肉脂肪则逐渐下降并趋于稳定,在100 mg/kg达到最小值,100~400 mg/kg差异不显著;肠脂肪酶、血浆总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)含量及高密度/低密度脂蛋白胆固醇(HDL-C/LDL-C)均呈先升后降的趋势,除LDL-C在各组间差异不显著外,其余指标均在100~150 mg/kg达到最大值;添加肌醇能显著增强肝脏和肌肉中肉碱脂酰转移酶(CPT-I)和乙酰辅酶A羧化酶(ACC)的活性。与对照组相比,100 mg/kg肝脏CPT-I的增幅比例低于ACC的增幅比例,肌肉则相反;当肌醇添加水平为100~150 mg/kg时,肝脏和肌肉中超氧化物歧化酶(SOD)的活性显著升高,丙二醛(MDA)含量及血浆中谷丙转氨酶(ALT)、谷草转氨酶(AST)均显著降低。研究表明,实用饲料添加适宜的肌醇能改善草鱼的生长、饲料转化和肝脏功能,促进脂肪消化,加快脂肪酸的合成与分解代谢,使全鱼和肝脏增脂、肌肉降脂,且能够提高肝脏和肌肉的抗氧化机能。以FE和SGR为效应指标,草鱼实用饲料肌醇适宜添加量为90.3~96.4 mg/kg。     

饲料中添加生物素对草鱼幼鱼生长、体成分和血清生化指标的影响

在纯化饲料中分别添加生物素0、0.05、0.10、0.20、0.40、0.80、1.60 mg/kg投喂初始质量为(5.92±0.25)g的草鱼(Ctenopharyngodon idellus)幼鱼8周,研究了不同生物素添加量对草鱼幼鱼生长性能、饲料系数、机体营养成分、血清生化指标的影响。试验结果显示:与对照组相比,添加生物素提高了草鱼幼鱼的增重率、特定生长率,降低了饲料系数。添加量为0.40 mg/kg时草鱼幼鱼的特定生长率和增重率最大,饲料系数最低,并与对照组存在显著差异(P<0.05);添加不同水平生物素对草鱼幼鱼全鱼水分、粗蛋白、粗脂肪含量无显著影响,但添加量为0.40 mg/kg时粗蛋白含量最大。0.10 mg/kg组和0.20 mg/kg组的全鱼灰分含量显著高于对照组(P<0.05);添加生物素对血清总蛋白(TP)、血糖(GLU)和总胆固醇(TC)无显著影响,但显著提高了血清甘油三酯(TG)含量,各添加组TG含量均显著高于对照组(P<0.05),1.60 mg/kg添加组的高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)含量显著高于对照组(P<0.05)。综合本试验结果,草鱼幼鱼饲料中生物素适宜添加量为0.40 mg/kg。     

饲料中添加叔丁基氢醌对大菱鲆生长、血液生化指标、非特异性免疫及肠道组织结构的影响

为研究饲料中添加不同含量叔丁基氢醌(TBHQ)对大菱鲆幼鱼生长、血液生化指标、非特异性免疫及肠道组织结构的影响,在饲料中分别添加0、150、450和750 mg/kg的叔丁基氢醌,配制成4种等氮等脂实验饲料,选择初始体质量(8.31±0.04)g大菱鲆幼鱼,随机分成4组,每组6个重复,每个重复30尾,采用饱饲投喂方式,每天投喂2次,饲养周期为12 W。结果显示,与对照组相比,450和750 mg/kg TBHQ添加组大菱鲆的增重率、特定生长率均显著降低;450 mg/kg TBHQ添加组实验鱼血清碱性磷酸酶活力显著高于150 mg/kg TBHQ添加组;150 mg/kg TBHQ添加组实验鱼血清白蛋白和高密度脂蛋白含量显著低于对照组和450 mg/kg添加组;450 mg/kg TBHQ添加组鱼的血清肌酐含量显著高于对照组;150 mg/kg TBHQ添加组鱼的血清总蛋白含量显著低于对照组;饲料中添加高剂量的TBHQ能够显著升高血清中CAT、溶菌酶活力(450和750 mg/kg)及头肾吞噬细胞呼吸爆发活力(750 mg/kg);饲料中TBHQ添加量为750 mg/kg时,血清SOD活力显著降低;与对照组相比,饲料中添加450和750 mg/kg TBHQ能够显著降低中肠肠道绒毛长度与肠道直径比,而添加750 mg/kg TBHQ时中肠肠道做绒毛长度与肠道直径的比值显著降低。研究表明,饲料中TBHQ的添加量为150 mg/kg时,对大菱鲆幼鱼生长及生理生化指标无显著影响,而饲料中添加450 mg/kg以上的TBHQ则会对大菱鲆幼鱼的生长及生理状况产生一定负面作用。     

草鱼幼鱼对饲料中泛酸需要量的研究

研究了饲料中泛酸钙添加量对平均体重(4.80±0.32)g的草鱼幼鱼生长和部分生理指标的影响。在相同基础配方中分别添加泛酸钙0、8、15、30、60、120、240 mg/kg饲料,进行为期8周的养殖试验,每个处理3个重复。结果表明:饲料中添加泛酸钙能提高草鱼幼鱼的增重率和特定生长率,降低饲料系数,对成活率无显著影响(P>0.05)。对照组的总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇含量显著低于添加组(P<0.05),各添加组无显著差异(P>0.05)。鱼体灰分含量不受饲料中泛酸钙含量的影响,但能提高鱼体水分、蛋白和脂肪含量(P<0.05)。基于特定生长率折线法分析,草鱼幼鱼获得最佳生长时的饲料泛酸钙最低需求量为25 mg/kg。     

维生素C对泥鳅幼鱼生长和免疫的影响

水温21~26℃下,分别在基础饲料中添加不同含量的维生素C(以抗坏血酸多聚磷酸酯为维生素C源,添加量分别为0、50、120、240、360、500mg/kg),研究维生素C对(1.996±0.176)g泥鳅幼鱼的影响。试验结果表明,随着维生素C添加量的增加,泥鳅幼鱼的特定生长率呈现先升后降趋势,并在添加量为132.2mg/kg时达到最高值,显著高于其他几个试验组(P0.05)。组织和肌肉中的维生素C积累量随着饲料中维生素C添加量的增加呈先升后降趋势,在132.2mg/kg时和248.8mg/kg时分别达到最高。随着饲料中维生素C含量的增加,溶菌酶活性也呈现出先升后降趋势,在362.6mg/kg时达到最高,显著高于其他组(P0.05);血清总抗氧化能力呈上升趋势,以特定生长率和血清溶菌酶含量为指标,做折线模型回归分析最终求得泥鳅幼鱼饲料中维生素C的最适添加量分别为95mg/kg和423.3mg/kg。     

饲料中添加L-肉碱对吉富罗非鱼生长、肝脏脂肪代谢及抗氧化能力的影响

分别在3组等氮等能的吉富罗非鱼(GIFT,Oreochromis niloticus)饲料中添加不同水平的L-肉碱[0(对照组)、150和300 mg/kg],试验选用初始体重为(8.21±0.33)g的幼鱼投喂9周,探讨L-肉碱对吉富罗非鱼生长、体成分、血清生化指标、肝脏脂肪代谢酶活性和抗氧化能力的影响。结果表明:添加150或300 mg/kg L-肉碱显著提高了罗非鱼增重率(WGR)和特定生长率(SGR),显著降低了实验鱼肝体比(HSI)和脏体比(VSI);添加150 mg/kg L-肉碱组WGR和SGR最高,HSI和VSI最低。添加150 mg/kg L-肉碱显著提高了鱼体肥满度(CF)。饲料系数(FCR)和存活率(SR)在对照组和实验组间无显著差异。添加150或300 mg/kg L-肉碱显著提高了鱼体肝脏中粗蛋白含量,添加150 mg/kg L-肉碱显著降低了肝脏粗脂肪含量。添加150或300 mg/kg L-肉碱时,血清甘油三酯(TG)含量显著降低,肝脏脂蛋白脂酶(LPL)、肝脂酶(HL)、总酯酶(LPL)和脂肪酶(LPS)活性显著上升,肝脏过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-PX)活性显著增加,肝脏丙二醛(MDA)含量显著下降。添加300 mg/kg L-肉碱显著提高了鱼体肝脏超氧化物歧化酶(SOD)活性和溶菌酶(LZM)活性。综上,饲料中添加适量L-肉碱对提高吉富罗非鱼生长性能,促进其脂肪代谢和提高鱼体抗氧化能力有良好效果。基于L-肉碱对罗非鱼增重率和特定生长率的影响,推荐L-肉碱在吉富罗非鱼饲料中的添加量为150 mg/kg。     

投喂雌二醇对西伯利亚鲟幼鱼生长及血液生化指标的影响

采用投喂添加雌二醇饲料的试验方法,观察分析人工诱导西伯利亚鲟性逆转过程中,外源雌激素对西伯利亚鲟幼鱼生长和血液生化指标的影响。研究结果表明:高剂量组(10 mg E2/kg饲料)幼鱼的日增重、肥满度、特定生长率等均显著低于低剂量组(1 mg E2/kg饲料)、对照组和空白组(P0.05),且高剂量组血清中血糖和总胆固醇显著降低(P0.05),而总磷含量显著升高(P0.05)。     

饲料维生素E添加量对花鲈生长、组织中维生素E积累量和免疫指标的影响

采用单因子试验设计方法,进行了饲料中添加维生素E对花鲈生长(增重率、存活率、特定生长率、饲料效率)、组织中维生素E积累量和免疫指标(血清中溶菌酶活性和总补体活性)影响的研究,设计了5个不同维生素E水平(0.6、24.7、49.0、98.8、198.2 mg/kg)的等氮等能饲料,对花鲈进行为期8周的生长实验,每个水平含3个重复,每个养殖单元放养初始体重为10.1 g左右的花鲈20尾.饲养试验在海水网箱(1.5 m×1.0 m×1.0 m)中进行.结果表明:饲料中未添加维生素E组的增重率、饲料效率、特定生长率以及存活率显著低于维生素E添加组,随着饲料中维生素E添加量由0.6提高到49.0 mg/kg时,花鲈的增重率和特定生长率显著提高,以增重率和特定生长率为指标,花鲈最佳生长性能的饲料维生素E添加量为60.5 mg/kg左右;对鱼体生物学指标的分析表明,饲料中维生素E添加量达到49 mg/kg时能显著影响鱼体的肝体比指数,鱼体水分、粗脂肪不受饲料中维生素E添加水平的影响,然而对鱼体粗蛋白含量的影响显著;随着饲料中维生素E添加量由0.6提高到49.0 mg/kg时,花鲈肌肉和肝脏中维生素E的积累量显著升高,但当维生素E添加量达到49.0 mg/kg后,肌肉和肝脏中维生素E的积累量变化不显著;饲料中未添加维生素E组的花鲈血清溶菌酶和总补体活性显著低于维生素E添加组,花鲈血清溶菌酶和总补体活性随着维生素E添加量的增加而显著升高,饲料维生素E添加量达到98.8 mg/kg时,血清溶菌酶和总补体活性较高.综上所述,花鲈生长和免疫的维生素E适宜添加量为60.5～98.8 mg/kg.     

饲料中胆碱对大口黑鲈幼鱼生长性能、体成分和血清抗氧化机能的影响

为研究饲料中胆碱对大口黑鲈幼鱼生长性能、体成分以及血清抗氧化机能的影响，在基础饲料中分别添加0 (对照组)、700、1 400、2 100和2 800 mg/kg的氯化胆碱，配制成5组等氮等能的实验饲料(胆碱实测含量分别为2 369.57、2 716.90、2 993.49、3 443.60和3 799.05 mg/kg)，分别投喂初始体质量为(20.00±0.10) g的大口黑鲈幼鱼56 d。结果显示，实验鱼的增重率(WGR)和特定生长率(SGR)随着饲料中氯化胆碱添加量的提高呈先升后降的变化，在添加量为2 100 mg/kg的饲料组均达到最大值，显著高于对照组；饲料中添加氯化胆碱对实验鱼的存活率(SR)、肝体比(HSI)、脏体比(VSI)和肥满度(CF)无显著影响。当氯化胆碱添加量达到2 100 mg/kg饲料及以上时，鱼体肌肉和肝脏的粗脂肪含量均显著低于对照组。相比于对照组，添加1 400～2 800 mg/kg氯化胆碱组的鱼体血清中总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性显著提高，血清中丙二醛(MDA)的含量显著降低；氯化胆碱添加量为2...     

低聚壳聚糖对中华绒螯蟹生长性能、体成分、非特异性免疫及抗氧化能力的影响

为研究低聚壳聚糖对中华绒螯蟹生长性能、体成分、非特异性免疫及抗氧化能力的影响,实验选用个体均匀、初始均重为(16.20±1.30) g的中华绒螯蟹288只,随机分为4组,每组6个重复,每个重复12只,分别饲喂在基础日粮中添加0 (对照组)、25、50和100 mg/kg低聚壳聚糖的实验日粮,正式实验为期56 d。结果显示,与对照组相比,50和100 mg/kg低聚壳聚糖组中华绒螯蟹的饲料系数显著降低,可食内脏指数显著提高;50 mg/kg低聚壳聚糖组降低了中华绒螯蟹肌肉和可食内脏中粗脂肪含量,提高了蟹肌肉和可食内脏中超氧化物歧化酶和过氧化氢酶的活性;与对照组相比,50 mg/kg低聚壳聚糖组中华绒螯蟹碱性磷酸酶和酚氧化酶的活性显著提高。研究表明,添加低聚壳聚糖能够提高中华绒螯蟹生长性能、非特异性免疫和抗氧化能力,降低机体脂肪沉积,且添加量为50 mg/kg时效果较好。     

Effects of dietary vitamin E supplementation on growth performance,fatty acid composition,lipid peroxidation and peroxisome proliferator-activated receptors (PPAR) expressions in juvenile blunt snout bream <Emphasis Type="Italic">Megalobrama amblycephala</Emphasis>

A 9-week feeding experiment was conducted to evaluate the effects of dietary vitamin E (VE) supplementation on growth performance, liver fatty acid composition, lipid peroxidation and peroxisome proliferator-activated receptors (PPAR) genes expressions in blunt snout bream juveniles. Fish (average initial weight: 0.59 g) were fed diet supplemented with 0, 50, 100, 300 and 500 mg α-tocopherol acetate/kg in triplicates, which were found to, respectively, contain 11.2, 56.3, 114.6, 306.5 and 588.4 mg α-tocopherol/kg diet. Results showed that final weight, body weight gain and specific growth rate significantly increased with increasing dietary VE supplemented level from 11.2 to 56.3 mg/kg. When the broken-line model was employed to estimate the adequate requirement of vitamin E based on body weight gain, the optimal level was 55.5 mg/kg in diet. Hepatosomatic index value significantly decreased with incremental dietary VE levels. However, liver VE concentration showed a direct relationship with the dietary VE level. The percentages of 20:5n-3, 22:6n-3 and total n-3 long chain polyunsaturated fatty acids in liver increased with increasing dietary VE supplementation. Meanwhile, the expressions of PPAR-α, PPAR-β and PPAR-γ in liver were down-regulated by supplementation of dietary VE level from 56.3 to 588.4 mg/kg. In conclusion, supplementation of more than 55.5 mg/kg vitamin E may improve growth and increase n-3 LC-PUFA content in blunt snout bream, which is beneficial to human consumer.     

Effect of a Dietary Mixture of Beneficial Bacteria on Growth Performance,Health Condition,Chemical Composition,and Water Quality of Nile Tilapia,Oreochromis niloticus Fingerlings

ABSTRACT

Effects of dietary supplementation of Bifidobacterium longhum, Bifidobacterium thermophilum, Bacillus subtilis, and Lactobacillus acidophilus on growth performance, health condition, body chemical composition, and water quality of Nile tilapia (Oreochromis niloticus) fingerlings were evaluated. Five experimental treatments in triplicate were fed a diet containing 30% crude protein supplemented with variable inclusion of bacterial mixture: control, T1, T2, T3, and T4 containing 0, 1.0, 2.0, 3.0, and 4.0 g bacterial mixture/kg diet, respectively. Fish fed the T4 diet had the highest final body weight, weight gain, specific growth rate, thermal growth coefficient, feed intake, and the best feed conversion ratio. No significant differences in body chemical composition of fish were observed in terms of dry matter, crude protein, lipid, ash, and energy content among all treatments. Probiotic supplementation showed no noticeable differences on haematological and biochemical blood parameters, except for packed cell volume, albumin, albumin/globulin ratio, aspartate transaminase, glucose, uric acid, triglycerides, and cholesterol. Conclusively, Nile tilapia fingerlings diet supplemented with evaluated probiotic with an optimal dietary supplementation of 4 g/kg diet improved growth performance and fish health without a negative impact on water quality. This supplementation could therefore be used as a probiotic in Nile tilapia fingerlings diet.     

Effects of dietary coated protease on growth performance,feed utilization,nutrient apparent digestibility,intestinal and hepatopancreas structure in juvenile Gibel carp (Carassius auratus gibelio)

This study was conducted to investigate the effects of dietary protease on growth performance, feed utilization, whole‐body proximate composition, nutrient digestibility, intestinal and hepatopancreas structure of juvenile Gibel carp, Carassius auratus gibelio (mean weight 8.08 ± 0.18 g). Six diets were prepared, including a positive control diet (dietary protein 350 g/kg, PC), one negative control diet (dietary protein 33 g/kg, NC) and four protease supplementations diets, which were 75, 150, 300 and 600 mg/kg protease NC diet. After 12 weeks of diet feeding in indoor recycle aquarium tanks, no significant difference (p > .05) was found on growth performance between fish fed diet with 75–600 mg/kg protease and the PC group. Compared with the fish fed the NC diet, the specific growth rate of fish fed 300 mg/kg protease increased significantly (p < .05), as well as protein efficiency ratios (p < .05), while feed conversion was the opposite (p < .05). The nutrient digestibility of crude protein and lipid was higher (p < .05) in fish fed 150 mg/kg protease diet than the PC diet. Whole‐body proximate composition of fish was not affected (p > .05) by the dietary treatment. Serum alkaline phosphatase and albumin were significantly affected by dietary protease (p < .05), while the content of total protein, glucose, triglyceride, total cholesterol, aspartate aminotransferase and alanine aminotransferase activities in serum was not affected (p > .05). Foregut muscular thickness was thinner (p < .05), when the fish fed diets supplementation of protease in 150 or 600 mg/kg diet than the NC diet. Protease activities in hepatopancreas and foregut were higher (p < .05), in the fish fed 150 or 300 mg/kg protease diet than the fish fed the PC diet, but those in the mid‐ and hindgut were not significantly affected (p > .05) by the dietary treatments. Based on the regression analysis of weight gain rate, the optimal dietary inclusion level of protease was 400 mg/kg in the diet for juvenile Carassius auratus gibelio.     

Optimal dietary methionine requirement of juvenile Chinese sucker,Myxocyprinus asiaticus

A total of 630 juvenile Chinese sucker, with an average initial weight of 1.72 ± 0.05 g, were fed seven diets for 56 days to study the effect of dietary methionine levels on growth, feed utilization, body composition and haematological parameters on juvenile Chinese sucker. Diet 1 using fish meal as the sole protein source and diets 2–7 using fish meal and fermented soybean meal as intact protein sources supplemented with crystalline amino acids contained six levels of l ‐methionine ranging from 6.4 to 18.9 g kg^?1 of dry diet at a constant dietary cystine level of 3.7 g kg^?1. Each diet was randomly assigned to three aquaria. Results indicated that the highest weight gain, specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio and protein productive value occurred at 13.9 g methionine kg^?1 diet among the methionine supplemented dietary groups, beyond which they showed declining tendency. The whole body and muscle protein contents of juvenile Chinese sucker were positively correlated with dietary methionine level, while muscle lipid content was negatively correlated with it. The total essential amino acids content of muscle was increased significantly with increasing dietary methionine level from 6.4 to 13.9 g kg^?1 (P < 0.05). Apparent digestibility coefficients of dietary protein were significantly affected by dietary treatments. Serum protein, cholesterol and triacylglycerol increased with increasing dietary methionine levels, but showed a relatively lower value for fish fed the 18.9 g methionine kg^?1 diet. Quadratic regression analysis of SGR against dietary methionine level indicated that optimal dietary methionine requirement for juvenile Chinese sucker was 14.1 g kg^?1 of the diet in the presence of 3.7 g kg^?1 cystine (corresponding to 32.0 g kg^?1 of dietary protein on a dry‐weight basis).     

叶黄素对七彩神仙鱼生长和体色的影响

为研究叶黄素对七彩神仙鱼体色和生长的影响,在"牛心汉堡"饲料中分别添加0、50、100、200、300和400 mg/kg叶黄素,饲喂初始平均体质量(10.3±0.3)g的七彩神仙鱼8周。结果显示,添加叶黄素50~200 mg/kg,对鱼体增重率无显著影响,但添加量达200 mg/kg后,饲料系数显著增大,添加量达300 mg/kg后,增重率显著降低。在养殖4周、8周时,鱼体皮肤亮度(L*)无显著变化,皮肤黄度(b*)和叶黄素含量随叶黄素添加量增加而显著升高;8周时,各叶黄素添加组的皮肤b*值和叶黄素含量显著高于4周时,当叶黄素添加量达300 mg/kg后,皮肤b*值(4周、8周)和全鱼叶黄素含量(8周)趋于稳定;4周时,各处理组间的皮肤红度(a*)无显著差异;8周时,当叶黄素添加量达100 mg/kg后,皮肤a*值显著降低;饲料中添加300 mg/kg叶黄素显著提高了七彩神仙鱼肝脏总抗氧化能力。研究表明,在饲料中添加叶黄素可有效改善七彩神仙鱼体表黄色,提高肝脏总抗氧化能力,但高添加量的叶黄素会降低鱼体生长性能,七彩神仙鱼饲料中的叶黄素添加量建议为200~300 mg/kg。