Effects of replacing soybean oil with palm oil on growth performance, appetite and gut health in weaned piglets

Dan Li¹KUN WU¹Hanxin Liu²De Wu¹Lianqiang Che¹Zhengfeng Fang¹Bin Feng¹Shengyu Xu¹Yong Zhuo¹Lun Hua¹Josh Wen-Cheng Chiu³Guangmang Liu¹Yan Lin^1*

• ¹Key Laboratory of Animal Disease-Resistance Nutrition and Feed Science, Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, Sichuan, China
• ²College of Life Sciences, Sichuan Agricultural University, Yanan, Sichuan, China
• ³Ecolex Animal Nutrition, Kuala Lumpur 42920, Selangor, Malaysia

The effect of replacing soybean oil (SO) with palm oil (PO) on growth performance, feeding regulation, and microbial diversity of weaned piglets is investigated. We randomly allocate 144 21-d-old weaned piglets (Duroc × Landrace × Yorkshire) to 4 treatments with 12 replicates (3 piglets/replicate). The control group (CON) used 4% SO as the lipid source, while the experimental groups replaced 25% (T1), 50% (T2), and 100% (T3) of the SO with PO, respectively. The study lasted for 35 days. Average daily gain (ADG) increased in T1 and T3 and the feed/gain ratio (F/G) decreased from 0–14 d (P < 0.05). Additionally, the replacement of SO with PO tended to decrease the diarrhea index from 0–28 d (P =0.08). ADG in T3 increased from 0–28 d, as did average daily feed intake (ADFI) throughout the experimental period (P < 0.05). Digestibility results indicated that PO reduced ether extract digestibility (P < 0.05). Contents of palmitic acid (C16:0) in diet correlated positively with ADFI but negatively with ether extract and detergent fiber digestibility (P < 0.01). Although no significant differences were observed in intestinal villus morphology, the mRNA expression of ZO-1, Claudin-1, mTOR, and AMPK was significantly upregulated in the T3 group (P < 0.05). The relative expression of neuropeptide Y (NPY) in T3 and Agouti-related protein (AGRP) in T1 of the hypothalamus increased significantly, (P < 0.05). Microbial operational taxonomic unit abundance increased on day 14 (P < 0.05); at the genus level, in T3, the relative abundance of Roseburia increased significantly on day 14, and Ruminococcus-gauvreauii-group, Peptococcus, and Lachnospireceae-FCS020-Group increased significantly on day 28. The relative abundances of Ruminococcus-gauvreauii-group and Roseburia correlated positively with ADG, and that of Roseburia correlated positively with ADFI. Collectively, our observations suggest that moderate replacement of SO with PO positively affects weaned piglet appetite, growth performance, and gut microbial diversity, but high proportions may reduce nutrient digestibility.