为研究饲料中海带酶解提取物对斑点叉尾鮰生长和肝脏转录组表达的影响，在日粮中分别添加0 g/kg (S，对照组)、0.3 g/kg (KP3)、0.5 g/kg (KP5)、1.0 g/kg (KP10)、1.5 g/kg (KP15)、2.0 g/kg(KP20)的海带酶解提取物，以初始体质量为(51.18±1.14) g的斑点叉尾鮰为实验对象，随机分为6组，每组3个重复，每个重复40尾鱼，在池塘网箱中养殖60 d。结果显示：① 与对照组(S)相比，饲料添加海带酶解提取物对斑点叉尾鮰的存活率(SR)没有显著影响，特定生长率(SGR)提高了1.20%~5.39%，饲料系数(FCR)降低了−0.83%~9.09%；分别以SGR和FCR为目标进行二次多项式回归分析，得到海带酶解提取物在饲料中的最适添加量分别为0.98和0.96 g/kg；KP10~KP20组肥满度(CF)和脏体比(VSI)显著降低，KP10组肝体比(HSI)显著降低；各组全鱼的水分、粗脂肪、粗蛋白质和粗灰分含量差异不显著。② KP3组肠道皱襞高度，KP5组肠道皱襞高度、宽度、肌层厚度，KP10组的皱襞宽度均显著高于S组。③选取S组与KP10组鱼肝脏提取总RNA后进行转录组测序和基因差异表达分析，表达显著下调的基因数有81个，显著上调的有199个；GO功能分类分析结果显示，差异表达基因(DEGs)被注释到DNA转录、金属离子结合、膜及膜组成成分等条目上；KEGG pathway分析结果显示，DEGs主要富集到细胞增殖与分化、激素调控、脂类代谢、糖类代谢以及生长因子代谢等相关的12个显著差异代谢通路。研究表明，日粮添加海带酶解提取物可以促进斑点叉尾鮰生长，降低饲料系数，改善肠道形态结构，加强肝脏的糖脂代谢能力，适宜添加量为0.96~0.98 g/kg。

The aim of this study was to investigate the effects of kelp enzymatic extract on the growth and hepatopancreas transcriptome of Ictalurus punctatus. We prepared different diets with enzymatic extract of kelp addition amount of 0 g/kg (S), 0.3 g/kg (KP3), 0.5 g/kg (KP5), 1.0 g/kg (KP10), 1.5 g/kg (KP15), 2.0 g/kg (KP20) to feed channel catfish in cage-culture for 60 days. Channel catfish [initial body weight (51.18±1.14)g] as exprimental object were randomly divided into 6 groups with 3 replicates per group and 40 individuals per replicate. The results showed that: ① Compared with the control group S, the addition of kelp enzymatic extract in diet had no significant effect on the suvival rate(SR) of channel catfish, the specific growth rate(SGR) increased by 1.20% to 5.39%, and the feed coefficient rate(FCR) decreased by −0.83% to 9.09%. A quadratic polynomial regression analysis was carried out with SGR and FCR as the targets respectively, and the optimal addition amount of kelp enzymatic hydrolysis extract in the feed was 0.98 and 0.96 g/kg. The condition factor(CF) and viscero-somatic index(VSI) decreased significantly in groups KP10 to KP20, and the hepatosomatic index(HSI) decreased significantly in group KP10. The moisture, crude fat, crude protein and ash of fish had no significantly difference in all groups. ② Height of duplicature in group KP3, height and width of duplicature and thickness of muscularis in group KP5, thickness of muscularis in group KP10 were all significantly higher than those in group S. ③ Total RNA was extracted from S and KP10 groups’ hepatopancreas. Transcriptome sequencing results showed that there were 81 significantly down-regulated genes and 199 up-regulated genes. GO functional classification analysis results indicated that differentially expressed genes(DEGs) were annotated to items such as DNA transcription, metal ion binding, membrane and membrane composition. According to the results of KEGG pathway analysis, we found that DEGs were mainly enriched in 12 related pathways including cell proliferation and differentiation, hormone regulation, lipid metabolism, carbohydrate metabolism, growth factor metabolism and so on. Our studies have indicated that adding kelp enzymatic extract to diet can promote the growth of I. punctatus, reduce feed coefficient, and have positive effects on the intestinal morphology and the glucose and lipid metabolic capability of liver and pancreas. The suitable addition amount was 0.96-0.98 g/kg.

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海带酶解提取物对斑点叉尾鮰生长的影响与氧化豆油损伤修复研究(P113401819)；国家重点研发计划“蓝色粮仓科技创新”重点专项(2019YFD0900200)