背景:断奶通常会导致仔猪的低采食量和体重减轻,动员脂质以激发能量。微生物来源的抗氧化剂(MA)在抗氧化方面表现出巨大的潜力,抗炎和代谢调节。
目的:研究断奶仔猪断奶后脂代谢的变化及MA对断奶仔猪生长性能和肝脏脂代谢的影响。
方法:在第一个实验中,断奶21日龄的仔猪在断奶日(d0)宰杀,断奶后4(d4)和14(d14)天(每天6只仔猪)。在第二个实验中,仔猪分为两组,接受MA(MA)和盐水灌胃(CON),分别。所有仔猪在21日龄时断奶,每组6只仔猪在25日龄时屠宰。
结果:在实验1中,血清TG,与d0相比,d4和d14的TC和LDL-C明显下降(P<0.05)。d0时血清瘦素高于d4和d14时(P<0.05)。血清ghrelin从d0到d14持续升高(P<0.05)。肝脏HSL和ATGL从d0到d4先升高,然后从d4到d14下降(P<0.05)。实验2中,与CON组相比,MA组21-25日龄的ADG和ADFI升高(P<0.05)。血清TC,与CON组相比,MA组肝组织TC和血糖明显升高(P<0.05)。MA组SCD1、ACAT2和PPARγ表达上调(P<0.05)。与p-AMPKα(Thr172)表达降低相反,核SREBP1c,MA组FASN、PPARγ较CON组升高(P<0.05)。
结论:断奶促进肝脏脂解,MA可通过调节AMPKα-SREBP1c通路促进脂质合成,从而提高断奶仔猪的生长性能。
Weaning usually causes low feed intake and weight loss in piglets, which mobilizes lipid to energize. The microbe-derived antioxidants (MAs) exhibit great potential in antioxidation, anti-inflammation, and metabolic regulation.
We aimed to investigate the changes of lipid metabolism postweaning and effects of MA on growth performance and hepatic lipid metabolism in weanling piglets.
In the first experiment, piglets weaned at 21 d of age were slaughtered on weaning day (d0), 4 (d4), and 14 (d14) postweaning (6 piglets per day). In the second experiment, piglets were divided into 2 groups, receiving MA (MA) and saline gavage (CON), respectively. All piglets were weaned at 21 d of age and 6 piglets from each group were slaughtered at 25 d of age.
In experiment 1, the serum triglyceride, total cholesterol (TC), and LDL cholesterol on d4 and d14 declined significantly compared with d0 (P < 0.05). The serum leptin on d0 was higher than that on d4 and d14 (P < 0.05). The serum ghrelin kept increasing from d0 to d14 (P < 0.05). The hepatic hormone-sensitive lipase and adipose triglyceride lipase first increased from d0 to d4 and then decreased from d4 to d14 (P < 0.05). In experiment 2, the average daily gain and average daily feed intake from 21 to 25 d of age increased in the MA group compared with the CON group (P < 0.05). The serum TC, hepatic TC, and glucose of MA group showed a significant increase than that of the CON group (P < 0.05). The expression of SCD1, ACAT2, and PPARγ were upregulated in the MA group (P < 0.05). Contrary to the decreased expression of phosphorylation of adenosine 5\'-monophosphate-activated protein kinase alfa subunit (Thr172), the nuclear sterol regulatory element-binding protein 1c, fatty acid synthase, and peroxisome proliferator-activated receptor gamma of MA group increased than that of CON group (P < 0.05).
Weaning promoted hepatic lipolysis and MA could enhance lipid synthesis by regulating adenosine 5\'-monophosphate-activated protein kinase alfa subunit-sterol regulatory element-binding protein 1c pathway, thus improving growth performance of weanling piglets.