TIMP2 promotes intramuscular fat deposition by regulating the extracellular matrix in chicken

The interaction between myocytes and intramuscular adipocytes is a hot scientific topic. Using a co-culture system, this study aims to investigate the regulation of intramuscular fat deposition in chicken muscle tissue through the interaction between myocyte and adipocyte and identify important intermediary regulatory factors. Our proteomics data showed that the protein expression of tissue inhibitor of metalloproteinases 2(TIMP2) increased significantly in the culture medium of the co-culture system, and the content of lipid droplets was more in the co-culture intramuscular adipocytes. In addition, TIMP2 was significantly upregulated(P<0.01) in muscle tissue of individuals with high intramuscular fat content.Weighted gene co-expression network analysis revealed that TIMP2 was mainly involved in the extracellular matrix receptor interaction signaling pathway and its expression was significantly correlated with triglyceride, intramuscular fat,C14:0, C14:1, C16:0, C16:1, and C18:1n9C levels. Additionally, TIMP2 was co-expressed with various representative genes related to lipid metabolism(such as ADIPOQ, SCD, ELOVL5, ELOVL7, and LPL), as well as certain genes involved in extracellular matrix receptor interaction(such as COL1A2, COL4A2, COL5A1, COL6A1, and COL6A3), which are also significantly upregulated(P<0.05 or P<0.01) in muscle tissue of individuals with high intramuscular fat content.Our findings reveal that TIMP2 promotes intramuscular fat deposition in muscle tissue through the extracellular matrix receptor interaction signaling pathway.

The Effect of Dietary Vegetable Oilseeds Supplement on Fatty Acid Profiles in Milk Fat from Lactating Dairy Cows

To determine the effect of dietary supplementation with vegetable oilseeds on the composition of bovine milk fatty acids （FAs）, 40 Holstein dairy cows were used with a complete randomized design. At the beginning of the experiment, the cows were 150±25 day in milk （DIM）. Total duration of the experiment was six weeks. Measurements were made during the last three weeks. Cows in four treatments were fed with a basal diet （CT） or basal diet supplemented with either whole full fat soybean （WFS）, full fat expanded soybean （FPS） or whole full fat soybean with whole cottonseed and full fat expanded soybean （MIX）. The composition of the milk fat was analyzed by gas chromatography. Relative to control, the conjugated linoleic acid （CLA） concentration in milk fat from cows on FPS was significantly increased by 83.88% （P〈 0.05）. The proportions of C12：0 were decreased by 35.7, 35.51, and 38.65% in milk fat from cows on WFS, MIX, and FPS compared with cows on CT. Similar decreases in C 14：0 were 23.83, 24.85, and 31.48% in WFS, MIX, and FPS treatments, respectively. Feeding vegetable oilseeds increased the proportion of healthy FAs （mainly CLA）, whereas decreased the concentratiofi of C12：0 and C14：0. Therefore, milk and dairy products would have higher nutritive and therapeutic value.