ABSTRACT:The aim of this study was to assess the association of single nucleotide polymorphisms (SNP) of sheep fatty acid binding protein 4 (FABP4) gene with longissimus thoracis muscle (LT) meat quality traits in sheep. The FABP4 cDNA was cloned by RT-PCR method, and the sequence analysis showed that the open reading frame of sheep FABP4 is 399 bp and codes 132 amino acids. A mutation (A/G) detected in intron 1 of FABP4 gene was studied in 286 lambs of three Chinese native sheep breeds by PCR-SSCP procedure. Significant statistical association results revealed that AA genotype conferred higher tenderness (P < 0.05), muscle marbling score (P < 0.05) and intramuscular fat content (IMF; P < 0.05). Thus we suggested that the genotype AA could be regarded as a molecular marker for LT meat tenderness and IMF content in sheep.

The present study investigated the effects of dietary conjugated linoleic acid (CLA) on the cellular immune response of piglets after cyclosporin A (CsA) treatment. The experimental study had a 2 × 2 factorial design, and the main factors consisted of diets (0% or 2% CLA) and immunosuppression treatments (CsA or saline injection). CsA injection significantly increased feed : gain (F : G) of piglets ( P < 0.05); however, dietary CLA significantly decreased F : G of piglets ( P < 0.05). Dietary CLA partly ameliorated the deterioration of the feed conversion rate caused by CsA treatment ( P < 0.01). CsA treatment significantly decreased the percentages of CD4 + and CD8 + T lymphocytes in the thymus ( P < 0.01). Dietary CLA increased the percentages of CD4 + CD8 + double-positive and CD8 + single-positive T lymphocytes in the thymus ( P < 0.05), and had the trend to inhibit the decrease of CD4 + T lymphocytes in the thymus after CsA injection (P = 0.07). CsA treatment significantly depleted the peripheral blood CD3 + , CD4 + and CD8 + T lymphocytes ( P < 0.01). Dietary CLA significantly increased the number of peripheral blood CD8 + T lymphocytes and interleukin-2 (IL-2) production ( P < 0.05), and inhibited the decreases of peripheral blood CD3 + , CD4 + and CD8 + T lymphocytes counts ( P < 0.01) as well as IL-2 production ( P < 0.05) after CsA treatment. Dietary CLA partly rescued the decrease of lymphocyte proliferation after CsA injection ( P < 0.05). In summary, dietary CLA effectively ameliorated CsA-induced cellular immunosuppression in piglets.