Researches On The Developmental Changes Of Mrnas Expression Levels Of The Genes Related To Growing Or Intramuscular Fat In Sheep

This paper selected male Kazak sheep and Xinjiang fine wool sheep at different ages from day 2 to 120 (no 120-day Kazak) to explore the mechanism and characteristics of the mRNAs expression of the genes related to growing or IMF, so as to help the breeding of sheep. The researchs here mainly focused on these aspects : body weight at different ages was measured to draw the cumulative growth curves; the IMF content was detected by using Soxhlet petroleum-ether extraction; mRNAs expression level was analysed by the relative quantitative method real time PCR with GAPDH mRNA as the internal standard; The relativities between mRNAs expression levels of different genes and those between mRNAs expression levels and growing or IMF content were explored. The results were as follows:1. The developmental changes of mRNAs expression levels of ghrlin gene and its receptor gene GHSR in sheep1) Kazak sheep exhibited a higher growth rate than that of Xinjiang fine wool sheep between the early stage; 2) Ghrelin mRNA was distributed in all of the tissues including hypothalamus, pituitary, heart, liver, rumen, reticulum, omasum, abomasum, duodenum and longissimus dorsal muscle in Kazak sheep, with mostly existing in abomasums(P<0.01); 3) The abomasum ghrelin mRNAs expression level increased with growing in both breeds, and showed highly positively correlated with the cumulative growth curves. Furthermore, the abomasum ghrelin mRNAs expression level of Kazak sheep was significantly higher than that of Xinjiang fine wool sheep at any age(P<0.01). According to the results, it was showed that ghrelin may be highly related to sheep growing and developing; 4) The hypothalamus GHSR mRNAs expression level increased firstly and then declined with growing in both breeds. From day 60 to 90, the mRNAs expression level of male Kazak sheep were extremely higher than that of Xinjiang fine wool sheep(P<0.01); 5) The...