Short-chain fatty acids (SCFAs) play a regulatory role in various physiological processes in mammals and act as endogenous ligands for the G protein-coupled receptors (GPR) 41 and 43. The role of GPR41 and GPR43 in mediating SCFA signaling in the rabbit remains unclear. The present study was to investigate the sequence of the GPR41 and GPR43 messenger RNA (mRNA) and their expression pattern in different tissues and developmental stages in New Zealand rabbit. Comparison of genomic sequences in GenBank using the Basic Local Alignment Search Tool program suggested that the New Zealand rabbit GPR41 mRNA has high similarities with the human (84%), bovine (84%) and Capra hircus (84%) genes. Similarly, GPR43 mRNA has high similarity with the rat (84%) and mouse (84%) genes. Real-time PCR results indicated that GPR41 and GPR43 mRNA were expressed throughout rabbit’s whole development and were expressed in several tissues. G protein-coupled receptor 41 and GPR43 mRNA were most highly expressed in pancreas (P<0.05) and s.c. adipose tissue (P<0.05), respectively. The expression levels of GPR41 mRNA was down-regulated in duodenum, cecum (P<0.05) and pancreas and up-regulated in jejunum, ileum, adipose tissue and spleen during growth. G protein-coupled receptor 43GPR43 mRNA was highly expressed in the duodenum, jejunum, ileum, colon, cecum and lung at 15th day (P<0.05), whereas the expression levels in the pancreas and spleen increased later after birth, with the highest expression at 60th day (P<0.05).

To investigate the phylogeny of benign Theileria parasites, we determined the complete major piroplasm surface protein (MPSP) gene sequences for 6 benign theilerial organisms, including the first from tick. Sequences were analysed alongside published sequences for 39 benign Theileria parasites, using Bayesian inference and maximum parsimony. All MPSP sequences were 852 nucleotides, except for Gansu, Wuchangbuf, VB01, and VB01; Gansu contained 873 nucleotides, and the other 3 had 855. Deduced amino acid sequences contained 284 residues, except for Gansu (291) and Wuchangbuf, VB01, and VB01 (285 each). Pairwise comparisons showed identities among 45 theilerial MPSP sequences ranging from 70·9 to 99·8% for nucleotide and 71·0 to 100% for amino acid sequences. Our results clearly indicate that all global parasites, excluding Brisbane, were classified into 1 of 8 types; 6 types of Theileria exist in Korea. Each type, excluding Type 6, has several type-specific amino acid sequences. The phylogenetic tree derived from the nucleotide sequences showed 2 sister-group relationships, Type 2+Type 7 and Type 3+Brisbane, with a new branching pattern: (Type 6 (Type 8 ((Type 2, Type 7), (Type 1, (Type 4, (Type 5, (Type 3, Brisbane))))))). Our sequence data showed no geographical influence on worldwide Theileria parasite distribution.