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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (5): 159-170.DOI: 10.11686/cyxb2022217

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Effects of starter feed in different physical forms on the rumen transcriptome of lambs

Rui-xin YANG1(), Yong LI1,2, Xiao-fang CAI1, Cheng-xing HAN1, Yan-li GUO1()   

  1. 1.College of Animal Science and Technology,Gansu Agricultural University,Lanzhou 730070,China
    2.College of Animal Husbandry Engineering,Henan Vocational College of Agriculture,Zhengzhou 451450,China
  • Received:2022-05-18 Revised:2022-08-31 Online:2023-05-20 Published:2023-03-20
  • Contact: Yan-li GUO

Abstract:

The physical form of the starter feed can affect the rumen development of ruminants. In this study, we investigated the effects of different physical forms of starter feed on the rumen transcriptome of pre- and post-weaning lambs. The overall aim was to explore the molecular mechanism by which starter feed in different physical forms affects the rumen development of lambs. Twenty-four 8-day-old male Hu lambs with similar birth weight [average, (5.04±0.75) kg body weight] were randomly assigned to two groups with 12 lambs per group. Each lamb was considered to be one replicate. The two groups were assigned to one of two dietary treatments (pelleted starter, PS; and textured starter, TS). Lambs were fed from their dams until 7 days of age and were separated from them at 8 days of age. From 8 to 35 days of age (pre-weaning), the lambs were bottle fed with milk replacer (MR) with ad libitum access to their respective starter feed. Feeding with MR was stopped at day 35. Six lambs per treatment were euthanized pre- (21 d) or post-weaning (42 d) for sampling. The abdominal sac tissue was collected from the rumen. RNA-Seq was used for transcriptome sequencing. A total of 4478 genes were differentially expressed between the two groups. Compared with the PS group, the TS group showed 194 up-regulated genes and 293 down-regulated genes pre-weaning, and 1763 up-regulated genes and 2228 down-regulated genes post-weaning. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that the differentially expressed genes were mainly enriched in key metabolic pathways such as peptide and amino acid biosynthesis, peptide metabolism, carbohydrate metabolism, lipid metabolism, butyric acid metabolism, pyruvate metabolism, and apoptosis. According to the enrichment results, 15 differentially expressed genes were selected for verification of their expression patterns by qRT-PCR. The results obtained from the qRT-PCR analyses were consistent with those obtained from transcriptome sequencing. In conclusion, the up-regulation of genes related to fatty acid metabolism, cyclins and kinases, and growth, and down-regulation of genes related to apoptosis of the rumen epithelium of the TS group may be the important factors in promoting the rumen development of lambs.

Key words: pelleted starter, textured starter, transcriptomics, rumen, lambs