最新研究摘要 I 凡纳滨对虾免疫，酵母有何妙用？ / 开普饭

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本期主题

酵母与凡纳滨对虾

赖氨酸水平与草鱼幼苗

家禽副产品替代鱼粉

不同食用油与短鳍金鲳鱼

酵母和酵母提取物对凡纳滨对虾幼体生长性能、

抗氧化能力和肠道菌群的影响

凡纳滨对虾是目前世界上最重要的经济虾类之一。在中国，凡纳滨对虾产量居世界首位。近年来，随着水质恶化和新型疾病的出现，对虾疾病发生日益频繁，养殖病害所造成的损失也更为突出。

预计凡纳滨对虾产量将持续增长（图源：

中国南美白对虾产业发展报告）

新普乐是源自奥特奇专利菌株的高品质蛋白源，更是一种功能性蛋白源。其已被多次证明能够对水生动物生长性能、抗氧化能力和免疫力有着非常积极有效的作用。近期，新普乐有效改善凡纳滨对虾生长性能、抗氧化能力及丰富肠道微生物多样的文章被Aquaculture杂志收录，以下为文章摘要：

采用为期8周的饲养试验，研究酵母和酵母抽提物（奥特奇新普乐TM）对凡纳滨对虾（Litopenaeus vannamei）生长性能、抗氧化能力和肠道菌群的影响。将添加0%（对照）、3%啤酒酵母（Y）、0.5%酵母抽提物（YE0.5）、1%酵母抽提物（YE1）和2%酵母抽提物（YE2）的5组饲料分别投喂给凡纳滨对虾（每组饲料4个重复，每个重复30只虾，初始体重1.38±0.01 g）。

结果表明，与对照组相比，YE2组对虾的增重率和特定生长率均高于对照组（P<0.05）。饲料中酵母和酵母抽提物均能提高对虾的肥满度（P<0.05）。饲喂酵母和酵母抽提物的虾体含水量显著低于对照组（P<0.05）。

新普乐有效提高凡纳滨对虾生长期终末均重

新普乐显著凡纳滨对虾特定生长率

对虾肥满度显著提高

与对照组相比，饲喂酵母抽提物的对虾总抗氧化能力更高（P<0.05）。饲喂YE2的对虾过氧化氢酶和谷胱甘肽过氧化物酶活性高于对照组、YE0.5和YE1组（P<0.05）。对虾肠道中主要细菌门有软壁菌门、变形菌门、拟杆菌门、厚壁菌门和放线菌门。随着饲料中酵母提取物添加量的增加，鲁杰氏菌属（Ruegeria，属于变形菌门、α变形菌纲、红杆菌目、红杆菌科）的相对丰度逐渐增加，显著高于饲料对照组和Y组（P<0.05）。

此外，酵母和酵母抽提物显著提高了肠道菌群的多样性指数（P<0.05）。总的来说，饲料中添加2.0%酵母抽提物显著提高了对虾的生长性能和抗氧化能力，也提高了凡纳滨对虾肠道微生物多样性和微生物群结构。

不同来源的酵母提取物在产品特性、营养品质上明显，外加下游加工工艺的不同，所以最终产物质量参差不齐。奥特奇专注酵母研究20多年，以专利菌株进行深层液态发酵所获原料，配以独特的破壁与酶解工艺，经过严格的质检监督，保证产品质量。

https://www.sciencedirect.com/science/article/pii/S0044848620328362

饲料中赖氨酸水平对草鱼幼苗生长性能、

全身成分及糖代谢和脂代谢相关基因表达的影响

采用8周饲养试验，测定对膳食赖氨酸的需求量，评价赖氨酸对草鱼（Ctenopharyngodon idellus）幼苗糖代谢和脂质代谢的影响。给720条鱼（初始体重0.36±0.00g）分别投喂6种不同赖氨酸水平（1.44%、1.79%、1.97%、2.44%、2.56%和2.87%干饲料）的饲料。结果表明，与对照组（1.44% 赖氨酸）相比，添加2.44%的赖氨酸可显著提高幼鱼的最终体重（FBW）、增重率（WGR）和特定生长率（SGR），采食量（FI）和饲料转化率（FCR）也是一样。

随着赖氨酸水平从1.44%提高到2.44%，鱼体全身脂肪含量降低，此后含量增加。在糖代谢方面，与对照组相比，2.44%的赖氨酸水平通过提高葡萄糖激酶（GK）和丙酮酸激酶（PK）mRNA水平显著改善糖酵解，同时，2.87%赖氨酸水平通过显著提高磷酸烯醇式丙酮酸羧激酶（PEPCK）和葡萄糖6磷酸酶（G6Pase）mRNA水平促进糖异生。

糖原合成酶（GS）mRNA水平与饲料处理无关。对于脂肪分解途径，2.44%的赖氨酸水平导致PPAR信号通路中激素敏感脂肪酶（HSL）、脂肪甘油三酯脂肪酶（ATGL）和肉碱棕榈酰转移酶-1（CPT1）mRNA水平的上调。与脂肪酸合成酶（FAS）、乙酰辅酶a羧化酶-1（ACC1）和硬脂酰辅酶a去饱和酶（SCD）一样，过氧化物酶体增殖物激活受体γ（PPAR-γ）在PPAR信号通路中的相对mRNA表达不受饲料中赖氨酸水平的显著影响。

此外，在所有处理组中，肠内甾醇调节元件结合蛋白-1（SREBP1）mRNA水平没有显著影响。根据折线回归分析，基于特定生长率和饲料转化率，草鱼幼苗对饲料中赖氨酸的最适需求量分别为2.39%和2.13%（6.34%和5.65%蛋白质）。总的来说，适当的糖酵解、赖氨酸可促进机体整体脂代谢水平的提高。

https://www.sciencedirect.com/science/article/pii/S0044848620315040

饲料中禽肉粉和家禽油对金头鲷幼鱼生长、

消化能力和肠道菌群的影响

本研究旨在评价家禽副产品粉（PBM）替代鱼粉（FM）对金头鲷（Sparus aurata）幼鱼的生长性能、饲料消化率、消化功能、肠道菌群的影响，为其在实际饲料中的应用提供经济分析。

配制六种等蛋白、等脂饲料，逐渐提高PBM水平（从0到37.5%）来代替鱼粉，相应的鱼粉蛋白质替代在饲料中高达83%。每种饲料被随机分配到三组鱼（初始体重63g），生长试验为期70天。各处理组幼鱼在生长性能、自愿采食量、饲料效率、氮利用率和全身成分方面没有差异。消化酶活性和蛋白质、磷和能量的表观消化系数也不受饲料处理的影响。在肠道微生物群方面，饲喂PBM 22.5的鱼表现出物种丰富度和消化道微生物多样性较高，但在黏膜OTUs、丰富度和多样性指数方面，各组之间没有差异。随着饲料中鱼粉被家禽副产品粉替代，饲料配方的成本降低，彰显了家禽副产品纳入商业饲料的潜力。

总的来说，本研究表明，在不影响生长性能和饲料利用率的情况下，金头鲷饲料中的鱼粉可被家禽副产品粉至少替代83%，同时还能提高饲料的经济效益。本研究旨在评价家禽副产品粉（PBM）替代鱼粉（FM）对金头鲷（Sparus aurata）幼鱼的生长性能、饲料消化率、消化功能、肠道菌群的影响，为其在实际饲料中的应用提供经济分析。

https://www.sciencedirect.com/science/article/pii/S004484862030805X

不同食用油源对短鳍金鲳幼鱼生长性能、

抗氧化能力和脂质沉积的影响

植物油（VO）作为水产饲料中鱼油的替代品，不仅影响鱼油的脂肪酸组成，而且影响脂肪的代谢和分布。本研究旨在探讨八种不同脂肪酸组成的典型植物油饲料在短鳍金鲳（Trachinotus ovatus）组织中的含量，包括椰子油（CO）、棕榈油（PO）、油茶籽油（OTO）、橄榄油（OO）、菜籽油（CNO）、花生油（PNO）、亚麻籽油（LO）和紫苏油（PFO），并与喂食鱼油（FO）的鱼进行比较。经过8周的饲养试验，配合饲料喂养的鱼生长性能最好，血清和肝脏的总抗氧化能力也高于其他组。

FO、PFO和LO组的鱼体粗脂肪含量和fas的表达水平较低，而OTO和PNO饲料中的脂肪含量和scd的表达水平较高。除投喂PFO的鱼外，其他植物油饲料组肝脏总脂含量均高于FO组，以OTO组和OO组最高。与脂肪酸分解代谢和转运有关的基因pparα、cpt1和apoB100在鱼饲料中的表达水平高于其他饲料。比较组织和饲料的脂肪酸组成，发现18:1n-9、18:3n-3（ALA）和22:6n-3（DHA）优先沉积在鲳鱼组织中，DHA优先沉积在极性脂类而非中性脂类中。

但PFO中过量的ALA并没有增加ALA的沉积量，反而增加了肝脏的脂质含量。本研究表明，饲料中的脂类来源对金鲳生长性能、抗氧化能力以及脂质沉积有显著影响。饲料中低18:1n-9、高n-3长链多不饱和脂肪酸和适当比例的ALA/LNA（18,2n-6）可减少鲳鱼组织中的脂质沉积，尤其是肝脏。

https://www.sciencedirect.com/science/article/pii/S0044848620320330

Effects of dietary lysine levels on growth performance, whole body composition and gene expression related to glycometabolism and lipid metabolism in grass carp, Ctenopharyngodon idellus fry

8 weeks rearing trial was designed to estimate the dietary lysine requirement, and evaluate the effects of dietary lysine on glycometabolism and lipid metabolism of grass carp fry. Six practical diets were prepared to feed 720 fish (initial weight 0.36 ± 0.00 g) with graded lysine levels (1.44%, 1.79%, 1.97%, 2.44%, 2.56% and 2.87%, dry diet). The results displayed that the final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) were significantly improved by 2.44% dietary lysine, the same as feed intake (FI) and feed conversion ratio (FCR), compared with those of the control group (1.44% dietary lysine). Whole-body lipid contents diminished with raising dietary lysine levels from 1.44% to 2.44% and thereafter the content increased.

Regarding glycometabolism, compared to the control diet, the 2.44% dietary lysine level significantly improved glycolysis by increasing glucokinase (GK) and pyruvate kinase (PK) mRNA levels, meanwhile the 2.87% dietary lysine level promoted gluconeogenesis by significantly increasing phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) mRNA levels. Glycogen synthase (GS) mRNA levels were independent of dietary treatment.

For the lipolysis pathway, the 2.44% dietary lysine level caused the upregulation of hormone sensitive lipase (HSL), adipose triglyceride lipase (ATGL) and carnitine palmitoyl transferase-1 (CPT1) mRNA levels in the PPAR signaling pathway. Like the fatty acid synthase (FAS), acetyl-CoA carboxylase-1 (ACC1) and stearyl-CoA desaturase (SCD), the relative mRNA expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) related to lipid synthesis in the PPAR signaling pathway, was not remarkably influenced by dietary lysine levels.

Furthermore, sterol-regulatory element binding protein-1 (SREBP1) mRNA levels in the intestine were not clearly affected among all the treatments. According to the broken-line regression analysis, based on the SGR and FCR, the optimum requirements of grass carp fry for dietary lysine were 2.39% and 2.13% of diet (6.34% and 5.65% of dietary protein), respectively. Overall, appropriate dietary lysine levels (2.44%) could improve the growth performance, reduce the whole-body lipid, promote glycolysis and lipolysis.

https://www.sciencedirect.com/science/article/pii/S0044848620315040

Effect of dietary poultry meal and oil on growth, digestive capacity, and gut microbiota of gilthead seabream (Sparus aurata) juveniles

This study aimed to evaluate the effect of replacing fish meal by poultry by-product meal (PBM) in actual commercial standard diets for gilthead seabream juveniles on growth performance, diet digestibility, digestive function, intestinal microbiota, and provide an economic analysis of using PBM in practical diets.

Six isoproteic and isolipidic diets were formulated including increasing levels (from 0 to 37.5%) of PBM in replacement of fish meal, corresponding to a fish meal protein replacement in the diets up to 83%. Each diet was randomly assigned to triplicate groups of fish (IBW 63 g) and the growth trial lasted 70 days. No differences between groups were observed on growth performance, voluntary feed intake, feed efficiency, nitrogen utilization, and whole-body composition. Digestive enzymes activity and the ADC of protein, phosphorus, and energy were also not affected by dietary treatment. Regarding gut microbiota, fish fed diet PBM22.5 showed higher species richness and diversity of digesta microbiota, but no differences between groups were observed in mucosa OTUs, richness, and diversity indices. The cost of diet formulation decreased with the dietary replacement of FM by PBM, highlighting the potential of poultry by-products inclusion in commercial diets.

Overall, this study indicates that dietary FM could be replaced at least up to 83% with PBM in diets for gilthead seabream juveniles without affecting growth performance and feed utilization while improving the economic efficiency of these diets.

https://www.sciencedirect.com/science/article/pii/S004484862030805X

Effects of different dietary oil sources on growth performance, antioxidant capacity and lipid deposition of juvenile golden pompano Trachinotus ovatus

Vegetable oils (VO) that are used to substitute fish oil in aquafeeds may affect, not only the fatty acid composition, but also lipid metabolism and distribution. The present study was designed to investigate this issue in juvenile golden pompano Trachinotus ovatus fed eight diets formulated with typical VO with widely varying fatty acid compositions including coconut oil (CO), palm oil (PO), oil-tea camellia seed oil (OTO), olive oil (OO), canola oil (CNO), peanut oil (PNO), linseed oil (LO) and perilla oil (PFO), in comparison with fish fed fish oil (FO). After the 8-week feeding trial, fish fed the CO diet had the highest growth performance, and higher general antioxidant capacities in serum and liver than in fish fed the other VO.

The crude lipid content in whole body and expression levels of fas were lower in fish fed the FO, PFO and LO diets, while lipid contents and expression levels of scd were higher in fish fed the OTO and PNO diets. Other than fish fed the PFO diet, the total lipid contents of liver in other fish fed the other VO diets were higher than that in fish fed the FO diet, with the highest contents in fish fed the OTO and OO diets. The expression levels of genes involved in fatty acid catabolism and transport,namely pparα, cpt1 and apoB100, were higher in fish fed diet PFO than in fish fed the other diets. Comparing the fatty acid compositions of tissues and diets showed that 18:1n-9, 18:3n-3 (ALA) and 22:6n-3 (DHA) were preferentially deposited in tissues of pompano, with DHA preferentially deposited in polar lipids rather than neutral lipids.

However, excessive dietary ALA in PFO did not lead to increased deposition of ALA, but increased liver lipid content. The present study showed that dietary lipid sources had significant influences on growth performance and antioxidant capacity, as well as on lipid deposition. Low dietary 18:1n-9, high n-3 long-chain polyunsaturated fatty acids and an appropriate ratio of ALA/LNA (18,2n-6) could reduce lipid deposition in pompano tissues, especially liver.

https://www.sciencedirect.com/science/article/pii/S0044848620320330

Effects of yeast and yeast extract on growth performance, antioxidant ability and intestinal microbiota of juvenile Pacific white shrimp (Litopenaeus vannamei)

An 8-week feeding trial was proceeded to assess the effects of yeast and yeast extract on growth performance, anti-oxidant ability and intestinal microbiota of Litopenaeus vannamei. Five diets supplemented with 0% (Control), 3% beer yeast (Y), 0.5% yeast extract (YE0.5), 1% yeast extract (YE1) and 2% yeast extract (YE2) respectively were assigned to L. vannamei (four replicates per diet, 30 shrimp in each replicate, initial body weight 1.38 ± 0.01 g).

The results showed higher weight gain and specific growth rate in shrimp fed diet YE2 compared with those fed the Control (P < .05). Both dietary yeast and yeast extract increased condition factor of shrimp (P < .05). Whole body moisture was significantly lower in shrimp fed yeast and yeast extract than those fed diet Control (P < .05). Shrimp fed yeast extract showed higher total antioxidant capacity compared to Control group (P < .05).

Shrimp fed diet YE2 obtained higher catalase and glutathione peroxidase activities than those fed diet Control, YE0.5 and YE1 (P < .05). The main phyla in intestine of shrimp were Tenericutes, Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. With the increasing dietary yeast extract supplementation, the relative abundances of Ruegeria, and its belonging Rhodobacteraceae, Rhodobacterales, Alphaproteobacteria, Proteobacteria in intestine increased gradually, which were significantly higher than those fed diet Control and Y (P < .05).

Moreover, yeast and yeast extract significantly increased the Shannon indexes of intestinal microbiota (P < .05). Overall, dietary 2.0% yeast extract supplementation significantly increased growth performance and antioxidant ability of shrimp, also enhanced microbial diversity and microbiota structure in intestine of L. vannamei.

https://www.sciencedirect.com/science/article/pii/S0044848620328362

最新研究摘要 I 凡纳滨对虾免疫，酵母有何妙用？

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