酵母提取物替代鱼粉对凡纳滨对虾消化机能的影响

为探明使用经氨基酸平衡后的酵母提取物替代鱼粉对凡纳滨对虾消化机能的影响,分别用酵母提取物替代饲料中15 %(B)、30 %(C)、45 %(D)、60 %(E)和100 %(F)的鱼粉,配制6种等氮、等能的试验饲料投喂凡纳滨对虾(6.328±0.630 g),以鱼粉含量为25 %的饲料为对照组(A)。饲养7 d后开始收集粪便,测定凡纳滨对虾对饲料的表观消化率。养殖试验结束后,研究酵母提取物替代鱼粉对凡纳滨对虾消化酶的影响。试验结果:凡纳滨对虾对各组饲料均具有较高的干物质表观消化率(77.96 %~81.21 %)和粗蛋白表观消化率(87.19 %~92.82 %)；各替代组饲料的表观消化率均高于对照组,其中C、E和F组的干物质表观消化率显著高于对照组(P<0.05),粗蛋白表观消化率随酵母提取物用量的增加而显著增加(P<0.05)；凡纳滨对虾肝胰腺中类胰蛋白酶的活性随饲料中酵母提取物用量的增加而显著升高(P<0.05),脂肪酶的活性随饲料中酵母提取物用量的增加而显著降低(P<0.05)；肝胰腺中淀粉酶活性最高的为C组；各替代组凡纳滨对虾的肠胰蛋白酶活性均高于对照组。结果表明,以氨基酸平衡酵母提取物替代饲料中的鱼粉可以提高凡纳滨对虾对饲料的消化机能。     

聚β-羟基丁酸酯对凡纳滨对虾肝胰腺免疫和消化指标的影响

以平均体质量为(5.66±0.14)g的凡纳滨对虾(Litopenaeus vannamei)为研究对象,分别投喂含聚β-羟基丁酸酯(PHB)质量分数为0%(对照组)、1%、3%和5%的对虾配合饲料,饲养35 d后检测并比较不同水平PHB对凡纳滨对虾肝胰腺免疫和消化指标的影响。结果显示,3%PHB添加组凡纳滨对虾的总抗氧化能力和溶菌酶活性显著高于对照组(P0.05)。Toll基因表达量随PHB含量的升高呈先上升后下降趋势,其中1%和3%PHB添加组的表达量显著高于对照组(P0.05);对照组HSP70基因表达量显著低于其他处理组(P0.05)。5%PHB添加组的淀粉酶、胃蛋白酶和胰蛋白酶活性显著升高(P0.05),而脂肪酶活性无显著变化(P0.05)。由此可见,饲料中添加适量的PHB有利于增强凡纳滨对虾肝胰腺的消化和非特异性免疫能力。     

酵母水解物对低盐胁迫凡纳滨对虾非特异性免疫及抗氧化能力的影响

本实验旨在研究饲料中添加酵母水解物对凡纳滨对虾在低盐度胁迫条件下非特异性免疫和抗氧化能力的影响。选取凡纳滨对虾[初始体质量（15.82±0.08）g],平均分为2组,对照组投喂基础饲料（Y0）,实验组投喂添加了3%酵母水解物的实验饲料（Y3）,在室内养殖15d后分别放入盐度为4‰（S4）和28‰（S28）的水体中进行盐度胁迫实验,每组6个重复,每个重复30尾虾（根据饲料和盐度不同组合,分组命名为Y0S4、Y0S28、Y0S3、Y0S28）。结果表明：饲料中添加3%酵母水解物对凡纳滨对虾血清酚氧化酶（PO）、总一氧化氮合成酶（TNOS）活性没有显著影响,但低盐度胁迫1h时,Y3S4组PO、TNOS活性显著高于Y0S4组;盐度因素对PO、TNOS活性产生显著影响,低盐度胁迫1h时,S28组PO、TNOS活性显著高于S4;饲料中添加3%酵母水解物显著提高了凡纳滨对虾肝胰腺超氧化物歧化酶（SOD）活性;盐度因素对酸性磷酸酶（ACP）活性产生了显著影响,S28组ACP活性显著高于S4。由此可见,在饲料中添加酵母水解物能够提高凡纳滨对虾肝胰腺SOD活性,提高对虾的抗氧化能力;在遭遇低盐度胁迫时,对虾能迅速恢复PO、TNOS活性至正常水平,从而提高凡纳滨对虾的抵抗不良环境的能力。     

饲料中添加沼泽生红冬孢酵母对凡纳滨对虾消化酶及肠道微生物的影响

在基础饲料中分别添加沼泽生红冬孢酵母干酵母和活酵母,在水温(26.2±1)℃、pH 7.4～8.0、盐度5条件下,进行为期6周的养殖试验.研究沼泽生红冬孢酵母对凡纳滨对虾肝胰腺消化酶和肠道微生物的影响.结果表明,饲料中添加干酵母,能显著提高凡纳滨对虾肝胰腺中蛋白酶和脂肪酶活性(P<0.05);添加活酵母,能显著提高蛋白...     

家蝇蛆粉替代鱼粉对凡纳滨对虾消化酶、转氨酶活性和肝胰腺组织结构的影响

试验采用28%鱼粉饲料为基础,以家蝇蛆粉分别替代20%、40%、60%、80%和100%的鱼粉配制5种试验饲料,投喂初始体质量为0.56 g的凡纳滨对虾（Litopenaeus vannamei）45 d,研究了蝇蛆粉对凡纳滨对虾消化酶、转氨酶活性和肝胰腺结构的影响。结果显示,替代组对虾肝胰腺、胃和肠道消化酶活性与对照组相比差异不显著（P＞0.05）。替代组对虾肝胰腺谷丙转氨酶（ALT）、谷草转氨酶（AST）活性均低于对照组,但差异不显著（P＞0.05）;随着替代水平的增加,血清ALT活性在100%替代组、AST活性在60%-100%替代组显著降低（P＜0.05）。与对照组相比,20%-60%替代组肝胰腺上皮细胞中空泡增多,并且出现未知物质;替代水平高于60%时肝胰腺结构损伤严重。结果表明,蝇蛆粉替代水平在60%以下时,对凡纳滨对虾消化酶和转氨酶活性没有显著影响,对肝胰腺结构损伤不明显。     

植物乳酸杆菌对凡纳滨对虾生长、消化酶活性和肠道组织形态的影响

将体质量(8.10±0.13)g的凡纳滨对虾放养在室内500L玻璃纤维水桶中,以不同剂量(0、0.5%、1.0%和2.0%)的植物乳酸杆菌菌液(密度109 cfu/mL)拌料投喂,观察凡纳滨对虾的生长、消化酶活性和肠道组织结构的变化。结果显示,投喂15d后,0.5%和1%菌液组对虾的平均体质量、质量增加率和特定生长率均显著高于对照组(P0.05),饲料系数显著降低(P0.05);0.5%菌液组对虾肝胰腺消化酶和肠道消化酶活性显著增强(P0.05),对虾肠上皮细胞高度显著增加(P0.05)。研究结果表明,投喂0.5%植物乳酸杆菌可显著提高凡纳滨对虾消化酶活性和肠上皮细胞高度,促进对虾生长。     

饲料中添加核苷酸对凡纳滨对虾幼虾生长、肠道形态及抗氧化酶活力的影响

本实验旨在研究外源核苷酸混合物对凡纳滨对虾(Litopenaeus vannamei)幼虾生长性能、体组成、中肠肠道形态和抗氧化酶活力的影响。选取960尾初始体质量为(1.01±0.02)g的凡纳滨对虾,随机分为8组,分别投喂基础饲料和添加5种核苷酸混合物(5′-腺苷酸∶5′-胞苷酸∶5′-尿苷酸二钠∶5′-肌苷酸二钠∶5′-鸟苷酸二钠=1∶1∶1∶1∶1,mix-NT)的实验饲料,各实验组添加量分别为0.1、0.2、0.4、0.6、0.8、1.0和1.2 g/kg饲料,养殖期为7周。结果显示,饲料中添加5种核苷酸混合物对凡纳滨对虾的特定生长率(SGR)和饲料系数(FCR)影响不显著(P>0.05)。外源核苷酸显著影响凡纳滨对虾全虾水分含量(P<0.05),但对全虾粗蛋白、粗脂肪和灰分含量影响不显著(P>0.05)。肝胰指数(HSI)随饲料中核苷酸添加量的增加而显著升高(P<0.05),在0.6 g/kg组达到最高。0.4 g/kg组的肝胰腺谷草转氨酶(GOT)和谷丙转氨酶(GPT)活力及尿酸(UA)含量最低,但与对照组相比差异均不显著(P>0.05)。中肠肠壁厚度和肠绒毛高度均随着核苷酸添加量的增加呈先升高...     

干露时间对凡纳滨对虾抗氧化功能的影响

将体长(8.32±1.43) cm健康有活力的凡纳滨对虾置于室温25℃的封闭实验台上,0、5、15、30 min后分别活体采样,测定肌肉、心脏、胃、肠道、肝胰腺和血淋巴的抗氧化相关指标,研究干露对凡纳滨对虾抗氧化功能的影响。试验结果表明,干露15 min组凡纳滨对虾胃、血清、肝胰腺丙二醛含量显著高于对照组(P0.05);随着暴露时间延长,干露组凡纳滨对虾肝胰腺组织总抗氧化能力呈下降趋势,各组与对照组相比显著降低(P0.05);肠道、心脏和胃总抗氧化能力水平呈先升后降的趋势;随着暴露时间的延长,凡纳滨对虾肝胰腺和肌肉中总超氧化物歧化酶以及肝胰腺中γ-谷氨酰半胱氨酸合成酶活性呈下降趋势,肌肉与肠道中的γ-谷氨酰半胱氨酸合成酶活性无显著性变化(P0.05)。短时间(5 min)干露对凡纳滨对虾组织抗氧化功能破坏较小,而长时间(30 min)干露可明显降低组织的抗氧化能力;干露对凡纳滨对虾对抗氧化功能的影响具有组织特异性。通过检测凡纳滨对虾抗氧化代谢指标,进而探索缺氧不同时间段凡纳滨对虾抗氧化酶活性的变化规律,总结对虾机体抗氧化剂和抗氧化能力的时空图谱,为养殖过程中缺氧现象提供基础资料,为凡纳滨对虾无水运输技术的开发提供参考数据。     

饲料中添加有机酸复合物对凡纳滨对虾生长、营养物质利用、血清生化指标和肠道微生物的影响

本实验研究了饲料中添加有机酸复合物对凡纳滨对虾(Litopenaeus vannamei)生长性能、营养物质利用率、肝胰腺酶活、血清非特异性免疫酶活性和肠道微生物组成的影响。在含鱼粉10%的基础饲料中分别添加0、0.05%、0.10%、0.15%的有机酸复合物(organic acids complex, OC,主要成分为富马酸、三丁酸甘油酯),制成4种等氮、等脂饲料(OC-0,OC-5,OC-10,OC-15)。将1 000尾(1.0±0.1) g对虾随机分配到20个网箱(每组5个网箱,每网箱50尾虾)中,分别投喂上述4种饲料8周。结果显示,和对照组相比,饲料中添加0.10%和0.15%有机酸复合物,增重率分别提高了18.7%和17.9%,饲料系数分别降低了16.1%和18.5%。在全虾成分方面,添加OC显著降低了全虾粗脂肪含量,OC-5,OC-10的粗蛋白含量也较对照组显著提高。饲料中添加有机酸复合物对凡纳滨对虾的营养物质消化率无显著影响,但显著提高了肝胰腺淀粉酶活性和血清超氧化物歧化酶活性。对肠道菌群的分析表明,饲料中添加0.10%OC增加了凡纳滨对虾肠道菌群丰度。综上,在饲料中...     

硒源对凡纳滨对虾生长、体组成和抗氧化能力的影响

水温(29.0±1.3)℃,将初始体质量(0.41±0.01)g的凡纳滨对虾随机分为4组,每组3个重复,饲养在室内循环水养殖系统中,投喂基础饲料(对照组)及在此饲料中分别添加硒含量相等(0.30mg/kg)的亚硒酸钠、酵母硒和蛋氨酸硒的4种饲料,养殖56d,比较了不同硒源对凡纳滨对虾生长、体组成和抗氧化能力的影响。试验结果表明,蛋氨酸硒组对虾的生长性能显著高于对照组和亚硒酸钠组(P0.05)。外源硒可显著影响对虾体蛋白和脂肪含量(P0.05),蛋氨酸硒组对虾机体营养成分显著优于其他组(P0.05)。添加外源硒组对虾的血清总抗氧化能力和谷胱甘肽过氧化物酶活性显著高于对照组(P0.05)。蛋氨酸硒组对虾血清丙二醛含量显著低于其他组(P0.05)。由此得出,饲料添加0.3mg/kg的硒能在一定程度上提高凡纳滨对虾的生长和抗氧化能力,蛋氨酸硒优于酵母硒和亚硒酸钠。     

饲喂乳酸菌对凡纳滨对虾幼虾肉质的影响

在凡纳滨对虾(Litopenaeus vannamei)幼虾饲料中添加3株植物乳杆菌[Lactobacillus plantarum YRL45、Lactobacillus plantarum QL、Lactobacillus plantarumKTP(C-2)]和3株副干酪乳杆菌(Lactobacillus paracasei M5、Lactobacillus paracasei X12、Lactobacillus paracasei SB27),采用质构仪TPA模式和气相色谱法分析喂养后肌肉质构和脂肪酸含量变化,研究乳酸菌对凡纳滨对虾幼虾肌肉品质的影响。结果表明,添加乳酸菌能改善凡纳滨对虾幼虾肌肉的弹性和咀嚼性,其中植物乳杆菌[YRL45、QL、KTP(C-2)]的改善效果最好,将幼虾肌肉的弹性和咀嚼性分别提高了35.14%和85.71%(P0.05)。副干酪乳杆菌(M5、X12、SB27)能提高对虾肌肉持水性并且能显著降低对虾肌肉中饱和脂肪酸含量,提高多不饱和脂肪酸含量,其中棕榈酸、十七烷酸和硬脂酸含量显著降低,EPA与DHA的含量分别增加了23.22%和34.40%。综上所述,在饲料中添加植物乳杆菌[YRL45、QL、KTP(C-2)]对凡纳滨对虾幼虾肌肉弹性和咀嚼性有改善作用,副干酪乳杆菌(M5、X12、SB27)能显著改善凡纳滨对虾幼虾肌肉的脂肪酸组成。     

Oral Administration of Hot‐water Extract of Tropical Brown Seaweed,Sargassum cristaefolium,to Enhance Immune Response,Stress Tolerance,and Resistance of White Shrimp,Litopenaeus vannamei,to Vibrio parahaemolyticus

The efficacy of hot‐water extract of tropical brown seaweed, Sargassum cristaefolium (SCE), supplemented in diets on immune response, stress tolerance, and disease resistance of Litopenaeus vannamei to Vibrio parahaemolyticus was evaluated. Shrimp were fed diets containing graded levels of SCE (0, 250, 500, 750, and 1000 mg/kg). The results showed that shrimp fed all diets containing SCE had significantly higher (P < 0.05) immune response in total hemocyte count (THC), differential hemocyte count (granular and hyaline cells), and phagocytic activity than those of shrimp fed the control diet. Similarly, in low dissolved oxygen stress tolerance test and the challenge test with V. parahaemolyticus, survival rates of shrimp fed all diets containing SCE were significantly higher (P < 0.05) (83–93% in stress test and 27–47% in challenge test) than those of shrimp fed the control diet (77 and 3.3%, respectively). These results suggest that oral administration of SCE at 500 and 750 mg/kg can be effectively used to enhance immune response, stress tolerance, and resistance of white shrimp, L. vannamei, against V. parahaemolyticus infection. These findings also confirm that using dietary SCE as immunostimulant is effective at increasing the nonspecific immune system in penaeid shrimp, L. vannamei.     

饲料中不同泛酸水平对凡纳滨对虾生长性能、饲料利用及血清指标的影响

为研究饲料中不同泛酸水平对凡纳滨对虾生长性能、饲料利用及血清指标的影响,实验配制6种等氮等脂(41%粗蛋白质和8%粗脂肪)的实验饲料,泛酸添加水平分别为0(对照组)、50、100、150、300和600 mg/kg,饲料中实测泛酸水平分别为20.9、69.3、99.0、150.2、304.4和513.6 mg/kg。选用初始体质量为(0.73±0.12)g的凡纳滨对虾720尾,随机分为6组(每组3个重复,每个重复40尾),进行为期8周的养殖实验。结果显示,饲料中不同泛酸水平对凡纳滨对虾增重率和特定生长率的影响不显著;对照组凡纳滨对虾成活率显著低于泛酸添加组,然而各泛酸添加组的成活率组间差异不显著。随着泛酸水平从20.9 m.g/kg增加到99.0 mg/kg时,饲料效率和蛋白质效率显著提高,而随着泛酸水平的进一步增加,饲料效率和蛋白质效率显著降低。饲料中泛酸水平对凡纳滨对虾全虾和肌肉主要成分无显著性影响。对照组对虾血清葡萄糖含量显著低于泛酸各添加组,然而泛酸各添加组之间无显著差异;投喂150.2 mg/kg泛酸组血清甘油三酯含量显著低于对照组和513.6 mg/kg;而血清总蛋白和胆固醇含量不受饲料中泛酸水平的影响。随着饲料中泛酸水平由20.9 mg/kg增至150.2 mg/kg,血清超氧化物歧化酶活力显著提高,而随着饲料中泛酸水平的进一步增加,血清超氧化物歧化酶活力显著降低;饲料中泛酸水平为99.0mg/kg组凡纳滨对虾血清总氧化能力显著高于其他各组;投喂对照组和泛酸水平为69.3mg/kg组的凡纳滨对虾血清丙二醛含量最高,投喂泛酸水平为150.2 mg/kg组血清的丙二醛含量显著低于其他各组。以凡纳滨对虾的饲料效率和蛋白质沉积率为评价指标,通过折线模型分析得到凡纳滨对虾泛酸最适需要量分别为113.40和119.87mg/kg。     

Replacement of Fish Meal with Soybean Meal,Alone or in Combination with Distiller's Dried Grains with Solubles in Practical Diets for Pacific White Shrimp,Litopenaeus vannamei,Grown in a Clear‐Water Culture System

The objective of this study was to evaluate inclusion of distiller's dried grains with solubles (DDGS) as partial replacement of commercial, solvent‐extracted soybean meal (SBM) in fish meal‐free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8‐wk feeding trial. Each 110‐L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM), which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10, 20, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre‐determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P < 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P > 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P < 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P > 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear‐water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.     

Effect of Dietary Supplementation of Acidic Calcium Sulfate (Vitoxal) on Growth,Survival, Immune Response and Gut Microbiota of the Pacific White Shrimp,Litopenaeus vannamei

Dietary acidifiers have been recognized as beneficial in animal production including aquacultural production of fish where they confer such benefits as improved feed utilization, growth, and resistance to bacterial pathogens. If improvements in growth and immune responses by acidifier supplementation can be confirmed in shrimp, then mortalities due to diseases could be minimized, limiting the emergence of disease‐resistant bacterial pathogens as a potential result of antibiotic misuse. With this in mind, a 35‐d feeding trial was conducted to evaluate growth, enteric microbiota populations, and nonspecific immune responses of Litopenaeus vannamei fed diets containing the commercial acidifier Vitoxal, based on acidic calcium sulfate in an indoor temperature‐controlled, recirculating culture system without any natural productivity. Experimental diets were formulated to contain 0 (basal), 0.4, 1.2, 1.6, or 2.0% acidic calcium sulfate (ACS) by weight. Shrimp fed in excess, 15 times a day using automatic feeders. Weight gain and survival among treatments were excellent, but not significantly different (P > 0.05). Denaturing gradient gel electrophoresis analysis revealed that the enteric microbial community of shrimp fed the basal diet differed markedly from those fed the acidifier on the basis of 64.9% similarity coefficient. Shrimp fed the commercial acidifier at 1.2 and 2.0% responded significantly (P < 0.05) better to reduced stress and displayed enhanced immune responses including hemocyte phagocytic capacity, hemolymph protein concentration, hyaline cell counts, and hemolymph glucose, compared with shrimp fed the basal diet. These results point to an enhanced performance in terms of positive shifts in the composition of enteric microbial communities as well as improved immune performance, with no changes in growth or survival.     

添加嗜酸乳杆菌对凡纳滨对虾生长、酶活性及相关酶mRNA表达的影响

本实验旨在研究饲料中添加嗜酸乳杆菌(Lactobacillus acidophilus)对凡纳滨对虾(Litopenaeus vannamei)幼虾生长、非特异性免疫酶活性、抗病力和相关酶m RNA表达的影响。选取840尾初始均重为(0.58±0.01)g的凡纳滨对虾幼虾为研究对象,分为7个处理,每个处理3个重复。投喂添加不同比例(0%,0.1%,0.2%,0.4%,0.6%,0.8%,1.0%)嗜酸乳杆菌的饲料,养殖期8周。结果显示:添加不同比例嗜酸乳杆菌对凡纳滨对虾的成活率无显著影响(P0.05)。增重率与特定生长率随添加量的增加呈先上升后下降的趋势,但均显著高于对照组(P0.05),在0.4%组达到最大值;当添加0.2%时,饲料系数最低,其他各组显著低于对照组(P0.05),而蛋白质效率的变化规律则与饲料系数相反。血清酚氧化物酶(phenoloxidase,PO)、碱性磷酸酶(alkaline phosphatase,AKP)和酸性磷酸酶(acid phosphatase,ACP)活性随添加量的增加先升高后降低,分别为0.4%、0.1%和0.2%时,达到最大值。过氧化氢酶(catalase,CAT)、溶菌酶(lysozyme,LZM)和超氧化物歧化酶(superoxide dismutase,SOD)活性,实验组均显著高于对照组(P0.05)。实验组过氧化氢酶(CAT)m RNA表达量和溶菌酶(LZM)m RNA表达量均显著高于对照组(P0.05)。哈维弧菌(Vibrio harveyi)攻毒96 h,对虾存活率随添加量的增加显著升高(P0.05)。以增重率(weight gain rate,WGR)为判断依据,根据折线模型得出,饲料中添加0.23%嗜酸乳杆菌可显著促进凡纳滨对虾生长,并提高非特异性免疫酶活性。     

Effects of dietary supplementation with β‐glucan and synbiotics on growth,haemolymph chemistry,and intestinal microbiota and morphology in the Pacific white shrimp

The goal of this study was to investigate the effects of dietary supplementation with β‐glucan and microencapsulated probiotics (Bacillus subtilis or Pediococcus acidilactici) on growth performance, body composition, haemolymph constituents, and intestinal morphology and microbiota of the Pacific white shrimp Litopenaeus vannamei. Four treatment diets [basal diet (C), β‐glucan‐containing diet (β‐glu), β‐glucan plus B. subtilis‐containing diet (β‐glu+Bs), and β‐glucan plus P. acidilactici‐containing diet (β‐glu+Pa)] were fed to L. vannamei for 90 days. Shrimp fed the β‐glu and β‐glu+Pa diets exhibited similar growth performance and body protein content, which were significantly higher than those of shrimp fed the control diet (P < 0.05). No significant differences in haemolymph triglyceride, cholesterol, protein, haemolymph urea nitrogen or chloride were detected among the experimental diets. However, dietary β‐glucan alone increased the haemolymph glucose level and osmolarity (P < 0.05). Synbiotic supplementation had greater effects on intestinal microbiota and morphology than dietary β‐glucan alone. For example, β‐glu+Bs increased the number of intestinal lactic acid bacteria and decreased the number of Vibrio spp. (P < 0.05), and β‐glu+Pa increased the height of intestinal villi.     

Effects of dietary Bacillus and medicinal herbs on the growth, digestive enzyme activity, and serum biochemical parameters of the shrimp Litopenaeus vannamei

White shrimp (Litopenaeus vannamei) was fed six different formulations of medicinal herbs (MH) and Bacillus in a feeding trial conducted for 56 days. The survival, growth, digestive enzyme activity, and serum biochemical parameters were assessed. A basal diet without MH and Bacillus was served as the control. At the end of feeding trial, survival ranged from 76.19% to 84.76% with no significant differences (P > 0.05) among all groups. Growth measured as final weight, specific growth rate (SGR), protein efficiency ratio (PER), protein productive value (PPV), and feed efficiency ratio (FER) were improved with increased dietary MH and Bacillus. Shrimp fed 0.2% MH and 0.3% Bacillus (Diet 23) were found to have the best growth performance. For shrimp fed Diet 23 final weight and SGR were significantly (P < 0.05) higher than for controls. The digestive enzyme activity of protease and amylase in hepatopancreas and intestines were significantly (P < 0.05) enhanced by the feed supplements, however amylase of the hepatopancreas was not affected. Serum protein and glucose content were enhanced by the supplement of MH and Bacillus. Serum cholesterol in shrimp of high Bacillus level groups was significantly (P < 0.05) higher than in the control group. However, no significant difference (P > 0.05) in serum Triacylglycerols between supplemented groups and control was found. Results revealed that the combined MH and Bacillus in diet could enhance growth because it can improve digestive enzyme activity and digestive metabolism.     

Growth performance,haematological parameters,antioxidant status and salinity stress tolerance of juvenile Pacific white shrimp (Litopenaeus vannamei) fed different levels of dietary myo‐inositol

A 10‐week growth trial was run to evaluate effects of myo‐inositol (MI) on growth performance, haematological parameters, antioxidative capacity and salinity stress tolerance of Litopenaeus vannamei. Six practical diets supplemented with graded levels of MI (designated as MI0, MI600, MI1200, MI2400, MI 3600 and MI4800 for 448.8, 974.2, 1568.0, 2810.6, 3835.5 and 4893.6 mg/kg diet, respectively) were fed to six replicate groups of L. vannamei (mean initial body weight 0.63 ± 0.00 g). The results showed that significant increment of growth performance was observed in shrimp fed MI600 diet than those fed MI1200 diet. Lipid concentration in whole body of the shrimp fed MI600 diet was significantly increased. Shrimp fed MI0 diet had lower total protein (TP) as compared to shrimp fed the MI‐supplemented diets (except MI4800 diet). In general, lower activities of antioxidant enzymes and higher malondialdehyde (MDA) content in haemolymph and hepatopancreas were recorded in shrimp fed MI0 diet, compared to those fed the MI‐supplemented diets. Reduced survival after 7‐h salinity stress was present in shrimp fed MI0 diet as compared to those fed MI4800 diet. Dietary MI requirement for glutathione peroxidase activity of L. vannamei was 2705 mg/kg diet.