饲料中添加谷胱甘肽对草鱼组织中谷胱甘肽沉积和抗氧化能力的影响

在基础饲料中分别添加还原型谷胱甘肽(GSH)至0 mg/kg、100 mg/kg、200 mg/kg、300 mg/kg、400 mg/kg和500 mg/kg,分别投喂草鱼(Ctenopharyngodon idella)幼鱼8周,草鱼幼鱼体质量(4.09±0.01)g,观察GSH在草鱼组织中沉积以及对草鱼抗氧化功能的影响.结果表明,饲料中添加外源GSH对草鱼生长影响不显著(P＞0.05),实验组肌肉中GSH含量显著高于对照组(P＜0.05),肝脏中GSH含量在GSH添加水平为200 mg/kg时显著高于对照组(P＜0.05),肝脏和肌肉中丙二醛(MDA)在GSH添加水平为300 mg/kg组达到最低,显著低于对照组(P＜0.05).添加GSH对血清中GSH和MDA影响不显著(P＞0.05).草鱼肝脏中谷胱甘肽还原酶(GR)活力在400 mg/kg组显著高于对照组(P＜0.05),肌肉中GR活力有增高趋势但差异不显著(P＞0.05);肝脏和肌肉中γ-谷氨酰转移酶(γ-GT)均高于对照组,分别在300 mg/kg组和200 mg/kg组达到显著水平(P＜0.05);肝脏中谷胱甘肽过氧化物酶(GSH-PX)活力、总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)能力不同程度升高,均在200 mg/kg组达到最高,显著高于对照组(P＜0.05);血清GSH-PX活力和T-AOC有增高趋势但与对照组差异不显著(P＞0.05);血清和肝脏中活性氧(ROS)含量分别在400 mg/kg和300 mg/kg组达到最低,显著低于对照组(P＜0.05).结果提示,饲料中添加GSH能够促进草鱼肝脏和肌肉中GSH的沉积,提高肝脏及肌肉中GR和γ-GT活力,以及肝脏中GSH-PX和SOD活力与总抗氧化能力,减少肝脏中MDA含量,降低肝脏及血清中ROS含量,因此GSH在水产饲料中具有广泛的应用前景.     

枸杞多糖对黄颡鱼免疫细胞活性的影响

选取540尾黄颡鱼,连续投喂含不同水平枸杞多糖的配合饲料(300、600、900、1200、1500 mg/kg饲料)8周.采用Percoll密度梯度离心等技术,对黄颡鱼头肾巨噬细胞和外周血白细胞进行分离纯化,使用NBT还原法、Griesse试剂显色法和MTT法测定头肾巨噬细胞的呼吸爆发活性和外周血白细胞的增殖能力,以探讨枸杞多糖对黄颡鱼免疫细胞活性的影响.试验结果表明:枸杞多糖各水平组均能显著地提高黄颡鱼头肾巨噬细胞的氧呼吸爆发活性(P＜0.05),且900～1200 mg/kg水平组的提高作用极显著(P＜0.01);虽然各水平组均能提高黄颡鱼头肾巨噬细胞的氮呼吸爆发活性,但只有1200～1500 mg/kg的水平组能极显著提高该活性(P＜0.01);枸杞多糖还能明显提高黄颡鱼外周血白细胞的增殖能力(P＜0.01).可见,枸杞多糖可以有效地提高黄颡鱼免疫细胞的活性.     

β-葡聚糖对花鲈免疫和抗氧化指标的影响

通过室内循环水养殖试验和氨氮急性应激试验,研究了饲料中添加β-葡聚糖对花鲈免疫和抗氧化指标的影响。选用体质量为(8.35±0.17)g的花鲈720尾,随机分成6组,每组4个重复,每个重复30尾鱼,分别投喂基础饲料和添加200、400、600、800、1000mg/kgβ-葡聚糖的试验饲料。6周生长试验结束后,对花鲈进行非离子氨质量浓度为3.29mg/L的氨氮应激试验,持续时间为96h。结果显示,与对照组相比,400~800mg/kg组免疫球蛋白M含量显著升高(P0.05),各添加组补体3含量均显著高于对照组(P0.05)。400~800mg/kg组血清碱性磷酸酶活性、400mg/kg组血清酸性磷酸酶活性、200~600mg/kg组血清一氧化氮含量显著高于对照组和其他添加组(P0.05)。与对照组相比,400mg/kg组血清总抗氧化能力和超氧化物歧化酶活性显著升高(P0.05),400~800mg/kg组丙二醛含量显著降低(P0.05)。各组血清过氧化氢酶活性差异不显著(P0.05)。应激后,200~600mg/kg组碱性磷酸酶活性、400mg/kg组和600mg/kg组酸性磷酸酶活性、400mg/kg组总抗氧化能力与对照组相比显著升高;400mg/kg组和600mg/kg组丙二醛含量显著降低。试验结果表明,饲料中添加适量β-葡聚糖能提高花鲈的免疫和抗氧化水平。     

饲料中添加L-肉碱对大菱鲆生长及肝脏脂肪酸的影响

在以鱼粉和大豆浓缩蛋白为蛋白源的基础饲料中分别添加0、200、400、600、800、1 000和2 000 mg/kg的L-肉碱配置7种等氮等能的试验饲料.经8周的摄食生长试验,结果表明:600 mg/kg添加组大菱鲆表现出最好的特定生长率,800mg/kg添加组大菱鲆表现出最好的饲料效率.各实验组间特定生长率及饲料效率均未表现出显著差异(P＞0.05).添加不同梯度L-肉碱对大菱鲆的肥满度、脏体比及肝体比未造成显著影响(P＞ 0.05).同时,各实验组大菱鲆体组成及肝脏脂肪酸含量无显著差异(P＞ 0.05).综合考虑L-肉碱对大菱鲆生长性能及经济效益,建议在以鱼粉为主要蛋白源的大菱鲆饲料不需添加L-肉碱.     

烟酸对杂交鲟幼鱼生长性能、肌肉品质和抗氧化功能的影响

为评价饲料中添加不同水平的烟酸对杂交鲟(Acipenser schrenckii♂×A. baeri♀)幼鱼生长性能、肌肉成分、肌肉质构和抗氧化性能的影响,在基础饲料中分别添加0 mg/kg、30 mg/kg、120 mg/kg、1200 mg/kg的烟酸配制成4种实验饲料,投喂初始体重(54.41±0.79)g的杂交鲟幼鱼84d,实验分为4组,每组3个重复,每个重复15尾鱼。结果表明:饲料添加不同水平的烟酸对杂鲟幼鱼增重率有显著影响(P0.05), 0 mg/kg组增重率显著低于30 mg/kg、120 mg/kg、1200 mg/kg烟酸组(P0.05),各添加组之间无显著差异(P0.05)。各组成活率、饲料系数和肝体比不受饲料烟酸的影响(P0.05)。120 mg/kg烟酸组的肥满度显著低于0 mg/kg、30 mg/kg、1200 mg/kg烟酸组, 0 mg/kg、30mg/kg、1200mg/kg烟酸组之间肥满度无显著差异(P0.05)。120mg/kg烟酸组的脏体比显著低于0mg/kg和1200 mg/kg烟酸组(P0.05),与30 mg/kg烟酸之间无显著差异(P0.05)。肌肉硬度和弹性随烟酸添加水平呈现先增加后降低的趋势, 1200 mg/kg烟酸组的肌肉硬度和弹性显著低于其余各烟酸添加组(P0.05)。30 mg/kg烟酸组的肌肉咀嚼性、回复性和黏性均在各组之间最大,且显著高于0 mg/kg、120 mg/kg、1200 mg/kg烟酸组(P0.05)。30 mg/kg烟酸组的肌肉凝聚性显著高于0 mg/kg、120 mg/kg、1200 mg/kg烟酸组(P0.05), 0 mg/kg、120 mg/kg、1200 mg/kg烟酸组之间无显著差异(P0.05)。肌肉水分、粗蛋白、粗脂肪和灰分含量不受饲料烟酸影响(P0.05)。30 mg/kg烟酸组肌肉T-SOD活力显著高于0 mg/kg和120 mg/kg烟酸组(P0.05),与1200 mg/kg烟酸组无显著差异(P0.05)。30 mg/kg烟酸组肌肉T-AOC活力显著高于0 mg/kg、120 mg/kg、1200 mg/kg烟酸组(P0.05), 0 mg/kg、120 mg/kg、1200 mg/kg烟酸组之间无显著差异(P0.05)。综上所述,饲料中添加烟酸对杂交鲟幼鱼的生长、肉质和抗氧化性能均有一定的改善作用,鲟鱼饲料中烟酸的建议添加量为30 mg/kg。     

硒和维生素E对牙鲆生长和非特异性免疫力的影响

在基础饲料中分别添加维生素E(VE)(60mg/kg标为e或300mg/kg标为E)和硒(Se)(0mg/kg标为s或2.5mg/kg标为S),制成4种试验饲料(s/e,s/E,S/e,S/E)分别饲喂初始体重为38.5±0.15g的牙鲆70d,观察其对生长性能、肝脏及血清中谷胱甘肽过氧化物酶(GSH-Px)活性、非特异免疫力以及抗病力的影响。结果表明,饲喂添加高剂量VE的两组饲料(s/E,S/E),牙鲆的特定生长率和吞噬率明显地提高(P0.05)。饲喂添加硒的两组饲料(S/e,S/E),牙鲆血液和肝脏的GSH-Px活性显著升高(P0.05)。70d投喂实验结束后,利用鳗弧菌进行攻毒试验,不添加硒和低剂量VE(s/e)使牙鲆的累积死亡率明显高于其他3组。     

金霉素粘杆菌素对肉鸡肠道微生物及核黄素营养的影响

中国农业科学院饲料研究所蔡辉益等用1日龄AA肉鸡840只,随机分为15个处理组,日粮分别深加两种不同剂量的金霉素(50和100mg/kg)和粘杆菌素(10和20mg/kg),结果均可显著降低28日龄肉鸡盲肠中大肠杆菌的数量(P＜0.05);且随着抗生素剂量的增加,其数量有继续降低的趋势.其中添加28mg/kg的粘杆菌素可显著提高28日龄肉鸡育肠中双歧杆菌的数量(P＜0.05),添加50mg/kg金霉素和10mg/kg粘杆菌素也使其略有提高,但差异不显著(P＞0.05);添加100mg/kg金霉素使其略有降低,但差异不显著(P＞0.05).     

半滑舌鳎鳃黏液免疫相关酶活性对黄芪多糖的免疫应答

在水温25℃下,给体质量(5.8±1.5)g的半滑舌鳎投喂在基础饲料中添加0、300、600、900、1200、1500mg/kg和1800mg/kg黄芪多糖的饲料后,每隔18d检测半滑舌鳎鳃黏液溶菌酶、过氧化物酶、碱性磷酸酶和酸性磷酸酶的活性,以检测半滑舌鳎鳃黏液对黄芪多糖的免疫应答及较佳剂量。90d的免疫结果显示,半滑舌鳎鳃黏液溶菌酶、过氧化物酶和碱性磷酸酶活性先增强后降低;半滑舌鳎鳃黏液酸性磷酸酶活性对低剂量(300~600mg/kg)和中高剂量(1200~1800mg/kg)黄芪多糖的免疫应答,随试验时间延长,分别呈增强及先增强后减弱的变化趋势。试验结束时,中低剂量(600~900mg/kg)黄芪多糖组半滑舌鳎鳃黏液溶菌酶、过氧化物酶、碱性磷酸酶和酸性磷酸酶活性均极显著高于对照组(P0.01)。从成本、高非特异免疫活性的角度看,半滑舌鳎配合饵料中黄芪多糖较佳添加剂量为600mg/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)。     

吉富罗非鱼对饲料中维生素B1的需要量

采用维生素B1(VB1)含量为0.08(对照组)、0.57、1.13、2.09、4.11和8.09 mg/kg的6种纯化饲料,分别饲养初始体质量为(64.4±1.5)g的吉富罗非鱼12周,研究VB1对其生长性能、部分血清生化指标、肝脏VB1蓄积量及转酮醇酶基因表达量的影响,以确定其对饲料VB1的需要量.结果显示,随着饲料中VB1含量增加,吉富罗非鱼增重率先呈线性增加后趋于稳定,当饲料中VB1含量为1.13、2.09、4.11、8.09 mg/kg时增重率达最大.吉富罗非鱼肝脏VB1含量随着饲料VB1含量增加不断增大,当增加到2.09 mg/kg后趋于稳定.饲料中缺乏VB1显著提高血清丙酮酸含量(P＜0.05),但对全鱼水分、粗脂肪、粗蛋白、灰分无显著性影响(P＞0.05).饲料中添加VB1显著提高血清高密度脂蛋白胆固醇和肝脏转酮醇酶基因表达量(P＜0.05).饲料中VB1含量大于1.13 mg/kg各组的肝脏转酮醇酶活性显著高于VB1含量小于0.57 mg/kg组(P＜0.05).折线回归分析表明,吉富罗非鱼(64 ～325 g)获得最佳生长时对饲料VB1需要量为1.16 mg/kg;肝脏VB1蓄积量达到最大时,对VB1的需要量为2.06mg/kg.     

Effect of Crude Palm Oil Incorporation on Growth,Survival, Feed Efficiency,and Body Composition of Heterobranchus longifilis Fingerlings

An 8-week feeding trial was carried out to determine the effect of increasing dietary palm oil levels on African catfish juvenile growth and nutrient utilization. Six isonitrogenous diets were formulated to contain 0.5% to 15% crude palm oil with dietary lipid levels ranging from 5% to 20%. Growth performance and protein utilization efficiency of African catfish responded in a positive manner to palm oil addition up to 9% (diet 14% lipid). No further improvement in growth was observed with higher levels of palm oil in the diets, and lower survival was observed with inclusion of 15% palm oil (diet 20% lipid). Whole-body lipid content increased when fish were fed with increasing levels of dietary lipid. Under our experimental conditions, the best growth rate and nutrient utilization were observed with the inclusion of 9% crude palm oil in the diets for African catfish.     

Optimal Dietary Protein Concentration for Hybrid Tilapia Oreochromis niloticus × O. aureus Fed All-Plant Diets

There are several estimates of the optimal dietary crude protein concentration for juvenile tilapia fed high quality animal proteins or mixtures of animal and plant derived feedstuffs. In the present study, the optimal dietary crude protein concentration for hybrid tilapia Oreochromis niloticus × O. aureus reared in glass aquaria was determined using diets free of fish meal. Further, initial weight of fish was approximately 21 g, which is the beginning of the growout phase of many commercial operations. The diets contained primarily corn co-products and soybean meal as the sources of amino acids, and were formulated to provide 24, 26, 28, 30, 32 or 34% crude protein. The diets were fed to quadruplicate groups of tilapia for 10 wk. Increasing concentrations of dietary crude protein resulted in proportional improvements in weight gain and feed efficiency up to 30% dietary crude protein. Fish fed 24% dietary crude protein exhibited significantly reduced weight gain compared to fish fed 28–34% dietary crude protein. Protein efficiency ratio (PER) of tilapia was unaffected by dietary crude protein concentration. However, fish fed 28% crude protein exhibited numerically higher PER (2.58) than fish fed other levels of crude protein. Muscle crude protein levels were lower in fish fed diets containing 24–28% crude protein than in fish fed 30% and higher concentrations. Quadratic regression analyses of weight gain and feed efficiency data indicated the optimal dietary crude protein concentration to be 29.65% and 28.33%, respectively, while broken line analyses indicated 27.5 and 27.3%, respectively. Based on weight gain, feed efficiency, PER, and proximate composition data, the authors recommend 28% dietary crude protein as the minimum for hybrid tilapia fed all-plant diets and reared in tanks.     

饲料碳水化合物水平对鳡幼鱼生长和体成分的影响

以白鱼粉、酪蛋白、鱼油和α-淀粉分别作为蛋白质、脂肪和碳水化合物原料,配制等蛋白质（45%）、等脂肪（8%）、碳水化合物水平分别为0%、5%、10%、15%、20%、25%的6组饲料。饲养鳡幼鱼8周后测定其生长、体成分及肝糖原含量,初步探讨鳡对碳水化合物的利用能力。结果表明,20%组鱼体的增重率、特定生长率和蛋白质效率最高（P〈0.05）。高碳水化合物组表现较高的摄食率、脏体比、肝体比和肠脂比（P〈0.05）。饲料碳水化合物水平的升高,增加了全鱼体干物质和粗脂肪的累积（P〈0.05）。随着饲料碳水化合物水     

Low Protein Diets for Channel Catfish Ictalurus punctatus Raised in Earthen Ponds at High Density1

This study was conducted to evaluate the use of low protein diets for channel catfish Ictalurus punctatus raised in earthen ponds at high density. Fingerling channel catfish were stocked into 0.04-ha earthen ponds at a rate 24,700 fish/ha and fed experimental diets daily to satiation from April to October 1995. The five diets contained either 32, 28, 24, 20, or 16% crude protein with digestible energy to protein (DE:P) ratios ranging from 8.9 to 16.2 kcal/ g protein. Weight gain was not different among channel catfish fed diets containing 32, 28, or 24% crude protein. Fish fed diets containing 20% or 16% crude protein gained less weight than fish fed the diets containing 28% or 24% crude protein, but not statistically less than the fish fed the 32% crude protein diet. Feed consumption data followed similar trends as weight gain data. Feed conversion ratio increased linearly as dietary protein decreased, but was not significantly different (multiple range test) for fish fed diets containing either 32% or 28% crude protein. There were no differences in survival and hematocrit of fish fed the different diets. No differences (multiple range test) were observed in dressout percentages for fish fed the various diets, but dressout percentage tended to decrease linearly as dietary protein decreased. Visceral fat and fillet fat increased and fillet protein and moisture decreased linearly as dietary protein decreased. Results from this study indicated that dietary protein concentrations as low as 24% are adequate for maximum weight gain of pond-raised channel catfish fed daily to satiation. Fish fed dietary protein levels below 24% grew relatively well, particularly considering that dietary protein was reduced 40–50% below that typically used in commercial channel catfish feeds. However, dietary protein levels below 24% may increase fattiness to an unacceptable level presumably because of the high digestible energy to protein ratio.     

Effect of dietary protein reduction with synthetic amino acids supplementation on growth performance,digestibility, and body composition of juvenile Pacific white shrimp, <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

Two experiments were conducted to evaluate the effect of lowering crude protein level and fish-meal inclusion rate by using commercially available synthetic amino acid supplements in practical diets on the growth performance of Litopenaeus vannamei. In experiment 1, three diets were formulated to assess whether 50% of fish meal could be replaced by soybean meal with synthetic amino acid supplementation. Diet 1 was formulated as the normal control with 20% fish meal and 36% crude protein; diet 2 was the negative control with 34% crude protein and half of the fish meal was replaced with soybean meal; and diet 3 was similar to diet 2 but was supplemented with amino acids to ensure the level of lysine, methionine plus cystine, and threonine similar to that in the diet 1. After a 70-day feeding trial, weight gain and specific growth rate of shrimps fed diet 2 were significantly lower than those fed diet 3, and numerically lower than those fed diet 1. Feed intake of shrimps fed diet 3 was significantly higher than those fed diets 1 and 2. There were no significant differences in feed conversion ratio among shrimps fed different diets. In experiment 2, four diets were prepared with diet 1 as the normal control with 41.26% crude protein, diets 2–4 were formulated to contain 39.81, 38.40, and 35.52% of crude protein with synthetic amino acids were added to simulate the amino acid levels of the diet 1. After a 70-day feeding trial, it was found that reducing dietary crude protein from 41.26 to 35.52% did not affect weight gain or feed conversion ratio. The survival of crude protein 35.52% treatment was significantly lower than other treatments. No difference was observed in body protein, lipid composition, and apparent digestibility coefficient among dietary treatments. Results of this study suggested that dietary crude protein could be reduced from 41.26 to 35.52% in the diets of L. vannamei as long as synthetic amino acids were supplemented.     

Effects of feeding soybean meal with varying trypsin inhibitor activities on growth of fingerling channel catfish

Uncooked hexane extracted soybean meal was heated for various lengths of time to produce meals with varying trypsin inhibitor activities. Fingerling channel catfish (Ictalurus punctatus) were fed 25 and 35% crude protein practical type test diets containing soybean meal with graded levels of trypsin inhibitor activity for 10 weeks. Growth rates and protein efficiency ratio (PER) values were reduced in fish fed raw and inadequately heated soybean meal at both protein levels. These effects were more severe at the lower dietary protein level. Growth rates and PER values improved in each study as the trypsin inhibitor activity of the soybean meal decreased to tolerable levels. Fish fed the 35% crude protein diets appeared to tolerate soybean meal with much higher trypsin inhibitor activity than fish fed the 25% crude protein diets. Even though growth rates and PER values were not significantly different over a rather wide range of dietary trypsin inhibitor activities, the best growth rates were not observed at either protein level until about 83% of the trypsin inhibitor activity in the soybean meal had been destroyed.     

Effects of various levels of dietary protein on survival,molting frequency and growth of juvenile blue crabs (Callinectes sapidus)

An 18-week study was conducted to examine growth characteristics of the juvenile blue crab (Callinectes sapidus Rathbun) fed various levels of dietary protein. Hatchery raised individuals (157) of identical age (160 days) from the same gravid female were assigned to one of four dietary treatments: adult brine shrimp (Artemia salina Leach) and artificial pelleted diets containing crude protein levels of 23, 37, and 49%.Growth rate, measured as a function of mean weight and mean carapace width, indicated that brine shrimp-fed crabs were larger (P < 0.05) than crabs fed artificial pelleted diets. Also, blue crabs fed either 37 or 49% crude protein were larger than crabs fed the 23% crude protein diet. Molting frequency was greater in the brine shrimp-fed crabs than in those fed the artificial diets. No differences in growth were detected when comparing males vs. females fed the artificial diets. However, females demonstrated greater growth than males within the brine shrimp treatment. Protein concentration of freeze-dried whole blue crab carcasses was greater in brine shrimp-fed crabs than in crabs fed the artificial pelleted diets (P < 0.05).     

Nutritional evaluation of dhaincha (Sesbania aculeata) seeds as dietary protein source for tilapia Oreochromis niloticus

An 8‐week feeding trial was conducted in a warmwater recirculation system at 27 ± 0.2 °C to evaluate the nutritive value of dhaincha (Sesbania aculeata) seed meal as a possible fish meal substitute in the diet of tilapia. Five isonitrogenous and isoenergetic diets were formulated to contain 32% crude protein and 18.4 kJ g^?1 gross energy. Sesbania seed meal was included in diets at various levels [0%, 9.7%, 19.4%, 29.1% and 38.8% for diets 1 (control), 2, 3, 4 and 5, respectively, which correspond to 0%, 10%, 20%, 30% and 40% of dietary crude protein]. Each treatment had two replicates, eight fish per replicate, with mean initial weight of 7.06 ± 0.03 g. Fish were fed 20 g kg^?1 metabolic body weight daily. On the basis of the observed growth rate, feed conversion ratio, protein efficiency ratio, apparent net protein utilization and energy retention, diets 1 (control) and 2 (containing 9.7% Sesbania meal) were similar and significantly (P < 0.05) better than the other dietary groups. Fish fed diets 3, 4 and 5 containing higher levels of Sesbania meal showed significantly reduced growth performance compared with those fed diets 1 and 2. Fish fed diets 3, 4 and 5 had significantly lower faecal dry matter (DM) content, apparent crude protein, lipid and energy digestibility and reduced levels of cholesterol compared with the control and diet 2. Fish fed diets containing higher levels (>9.7%) of Sesbania meal had significantly higher whole‐body moisture, lower lipid and gross energy content. The lower growth performance of fish fed diets containing higher levels of Sesbania meal is thought to result from the presence of tannins, saponin and the non‐starch polysaccharide content of the seed. The results of this study showed that inclusion of up to 9.7% untreated Sesbania seed meal (10% of the dietary protein) in the diet did not affect the growth performance and nutrient utilization in tilapia.     

Effect of Different Dietary Protein and Lipid Levels on Growth Performance and Body Composition of Juvenile Southern Flounder,Paralichthys lethostigma,Reared in a Recirculating Aquaculture System

The effects of six formulated diets containing different protein and lipid levels on growth performance and body composition of juvenile southern flounder were evaluated. Test diets were prepared with a combination of three crude protein (CP) levels (45, 50 and 55%) and two crude lipid (CL) levels (10 and 15%). Diets (CP/CL) were as follows: 45/10, 45/15, 50/10, 50/15, 55/10, 55/15 and a commercial diet (50/15). Southern flounder (1.10 g) were fed the respective diets for 42 d in triplicate recirculating tanks (20 fish/tank). Percent body weight gain (BWG) for fish fed diet 45/10 (413%) and the commercial diet (426%) were significantly (P < 0.05) lower than fish fed other diets (823–837%). Increasing protein level from 45 to 50% produced a significant increase in BWG for the 10% lipid diet (823%) but further increasing protein did not produce a significant effect on BWG irrespective of dietary lipid levels. Specific growth rate (SGR), feed intake, feed conversion efficiency (FCE), protein efficiency ratio (PER), and total lipid content in the whole body were significantly affected by different dietary protein and lipid levels. Results indicated that a combination of 50% protein and 10% lipid was optimal for the growth performance of southern flounder juveniles.     

不同蛋白水平饲料对台湾东风螺生长性能和体组成的影响

以优质鱼粉、豆粕等原料制成蛋白质含量不同的6组饲料(粗蛋白含量分别为48.16%、45.64%、40.67%、35.68%、30.80%、25.96%),喂养台湾东风螺47 d,以投喂鲜杂鱼组作为对照,分别于15、27、37、47 d测定螺高、螺宽、螺体重等生长指标,计算不同处理组在不同时间段(27、37、47 d)的饲料系数和蛋白质效率,试验结束后测定东风螺螺肉的体组成和氨基酸含量,研究结果表明:投喂颗粒饲料比投喂鲜杂鱼的饲料系数显著高;而当颗粒饲料中蛋白质含量变化(25%~48%)时,对东风螺生长性能并无显著影响。但随着饲料蛋白含量的增加,东风螺对饲料的利用率在一定程度上有所提高。当饲料中粗蛋白含量低于25%时,47 d时其饲料系数2.3,显著高于其他饲料组;蛋白质效率1.74显著低于蛋白含量48.16%饲料组。从东风螺生长性能和饲料利用分析,颗粒饲料中蛋白质含量不应低于25%。所有组东风螺螺肉的粗蛋白、脂肪,总氨基酸组成均无显著差异,但是一些中性氨基酸(如亮氨酸、异亮氨酸和丙氨酸)和精氨酸随着饲料蛋白含量的降低而呈现出降低趋势,部分组产生了显著差异。投喂颗粒饲料的东方螺生长不如投喂鲜杂鱼组。