RESUMO
The effects of Shirazi thyme as a medicinal plant on oxidant status (lipid peroxidation, protein oxidation, total antioxidant capacity, and catalase activity) and absorptive surface area were measured in three segments of the small intestine in cold-induced pulmonary hypertensive chickens. Birds were reared at four groups (thyme 0, 0.25, 0.50, and 1.00 % of diet) for 42 days. To induce pulmonary hypertension, the temperature was gradually decreased. The body weight was increased in thyme-0.25% birds compared to control ones, while it was decreased in thyme-1% of birds. The feed consumption was only increased in thyme-1.00% birds. The feed conversion ratio was lower in thyme-0.25% birds and higher in thyme-1.00% birds than control ones. The duodenal and jejunal villus surface area was lower in thyme-1.00% birds than control ones, while it was greater in the thyme-0.50% birds. The ileal villus surface area and duodenal lamina propria thickness were also greater in thyme-0.50% birds. Lipid peroxidation was only decreased in the duodenum and ileum of thyme-0.50% birds compared to control ones, whereas it was increased in the duodenum and jejunum of thyme-1.00% birds. Catalase activity was only elevated in the duodenum and jejunum of thyme-1.00% fed chickens. Total antioxidant capacity was increased in the duodenum, jejunum, and ileum of thyme-0.50% birds. It is concluded that the Shirazi thyme has beneficial effects on growth performance, intestinal absorptive surface area / secretory system, and pulmonary hypertension response at low doses (0.25 and 0.50% of diet), whereas high dose (1.00% of diet) of this plant may be toxic.
RESUMO
The main stage in real-time quantitative PCR is a quantification of gene transcriptomes, in which suitable use of reliable reference genes is critical to normalize accurately. To determine the most stable reference genes in laying hens under heat stress, from a panel of nine typical candidate reference genes, the mRNA transcript of ACTB, HMBS, HPRT1, RPL13, RPL32, 18SrRNA, TBP, TFRC, and YWHAZ was evaluated in the ovary and uterus of both control and heat-stress groups of laying hens. Forty 23-week-old White Leghorn laying hens were housed in two rooms. The control (n = 20) and heat-stress (n = 20) groups were maintained at 21-23 °C and 36-38 °C for 8 weeks respectively. Analysis of this set of genes was done with BestKeeper, geNorm, and NormFinder software programs to find the most stable ones. Candidate reference genes ranked in the uterus of heat-stress and control groups of hens included YWHAZ, HPRT1, HMBS, RPL13, TFRC, ACTB, TBP, RPL32, and 18SrRNA; those in the ovary were YWHAZ, HPRT1, TFRC, HMBS, RPL13, TBP, RPL32, ACTB, and 18SrRNA. The overall results indicated that the most stable genes are YWHAZ, HPRT1, HMBS, RPL13, TFRC, TBP, ACTB, RPL32, and 18SrRNA respectively. In addition, the combination of YWHAZ, HPRT1, and HMBS is suggested as the most stable reference group of genes for more accurate quantitative data normalization in the ovarian and uterine tissues of laying hens under control and heat stress conditions. Lay summary Heat stress influences the expression of many genes in the reproductive tissues of birds. Accurate evaluation of these changes via real-time quantitative PCR depends on the determination of reliable reference genes. In this study, nine candidate housekeeping genes were evaluated, and the most stable were YWHAZ, HPRT1, HMBS, RPL13, TFRC, TBP, ACTB, RPL32, and 18SrRNA.
