Enliang Song

Successful vitrification of mouse ovaries using less-concentrated cryoprotectants with Supercool X-1000 supplementation.

The purpose of our study was to investigate the feasibility of using less-concentrated cryoprotectants supplemented with ice blocker Supercool X-1000 to vitrify ovarian tissues. Mouse ovaries were cryopreserved in different concentrations of vitrification solution alone or with Supercool X-1000, and fresh non-frozen ovaries were used as control. The proportions of morphological normality of follicles, normal GCs in follicular fluids and developing to blastocysts were higher in 12.5% ethylene glycol (EG) + 12.5% dimethylsulfoxide (DMSO) with Supercool X-1000 than those of treated in 10% EG + 10% DMSO or 15% EG + 15% DMSO alone or with Supercool X-1000. In conclusion, the inclusion of Supercool X-1000 in less-concentrated vitrification solution was effective to improve the efficiency and efficacy of cryopreservation of ovarian tissues.

Gene expression profiling of SIRT1, FoxO1, and PPARγ in backfat tissues and subcutaneous adipocytes of Lilu bulls.

The temporal pattern of gene expression of sirtuin 1 (SIRT1), forkhead box O1 (FoxO1), and peroxisome proliferator-activated receptor-γ (PPARγ) in differentiating bovine preadipocytes and in backfat tissue from Lilu bulls 12, 18, 24, and 30 months old was investigated using real-time quantitative PCR; Carcass characteristics and adipocyte diameters were also measured. The upregulation of PPARγ and the downregulation of SIRT1 and FoxO1 were observed in the backfat tissue of Lilu cattle with increasing age. Moreover, the results showed that fat accumulation in Lilu cattle may primarily be related to an increase in mature fat cell numbers after 18 months of age. The present study indicates SIRT1 may play an important role in the development of bovine adipose tissue in vivo. Although SIRT1, FoxO1, and PPARγ expression appeared to be nonlinear during the stages of preadipocyte differentiation, these genes play an important role during bovine adipocyte development in Lilu cattle.

Substitution of Wheat for Corn in Beef Cattle Diets: Digestibility, Digestive Enzyme Activities, Serum Metabolite Contents and Ruminal Fermentation

The objective of this study was to evaluate the effect of diets containing different amounts of wheat, as a partial or whole substitute for corn, on digestibility, digestive enzyme activities, serum metabolite contents and ruminal fermentation in beef cattle. Four Limousin×LuXi crossbred cattle with a body weight (400±10 kg), fitted with permanent ruminal, proximal duodenal and terminal ileal cannulas, were used in a 4×4 Latin square design with four treatments: Control (100% corn), 33% wheat (33% substitution for corn), 67% wheat (67% substitution for corn), and 100% wheat (100% substitution for corn) on a dry matter basis. The results showed that replacing corn with increasing amounts of wheat increased the apparent digestibility values of dry matter, organic matter, and crude protein (p<0.05). While the apparent digestibility of acid detergent fiber and neutral detergent fiber were lower with increasing amounts of wheat. Digestive enzyme activities of lipase, protease and amylase in the duodenum were higher with increasing wheat amounts (p<0.05), and showed similar results to those for the enzymes in the ileum except for amylase. Increased substitution of wheat for corn increased the serum alanine aminotransferase concentration (p<0.05). Ruminal pH was not different between those given only corn and those given 33% wheat. Increasing the substitution of wheat for corn increased the molar proportion of acetate and tended to increase the acetate-to-propionate ratio. Cattle fed 100% wheat tended to have the lowest ruminal NH3-N concentration compared with control (p<0.05), whereas no differences were observed among the cattle fed 33% and 67% wheat. These findings indicate that wheat can be effectively used to replace corn in moderate amounts to meet the energy and fiber requirements of beef cattle.

Effects of Three Feeding Systems on Production Performance, Rumen Fermentation and Rumen Digesta Particle Structure of Beef Cattle

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight (575±10 kg) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate). The results showed that the average daily gain was significantly higher in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). Consumption per kg weight gain of concentrate, silage, and combined net energy (NEmf) were significantly decreased when cattle received TMR, unlike when they received SI1 and SI2 (p<0.05), indicating that the feed efficiency of TMR was the highest. Blood urea nitrogen (BUN) was significantly decreased when cattle received TMR compared with that in cattle receiving SI1 (p<0.05), whereas there was no difference compared with that in cattle receiving SI2. Ammonia nitrogen concentration was significantly lower in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). The rumen area of cattle that received TMR was significantly larger than that of cattle receiving SI1 (p<0.05), but there was no difference compared with that of cattle receiving SI2. Although there was no significant difference among the three feeding systems in rumen digesta particle distribution, the TMR group trended to have fewer large- and medium-sized particles and more small-sized particles than those in the SI1 and SI2 groups. In conclusion, cattle with dietary TMR showed increased weight gain and ruminal development and decreased BUN. This indicated that TMR feeding was more conducive toward improving the production performance and rumen fermentation of beef cattle.

Effect of mevalonic acid on cholesterol synthesis in bovine intramuscular and subcutaneous adipocytes

Mevalonic acid (MVA) is a key material in the synthesis of cholesterol; indeed, intracellular cholesterol synthesis is also called the mevalonic acid pathway. 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) is an essential enzyme in cholesterol biosynthesis. This study suggests that MVA may play an important role in the differentiation of bovine adipose tissue in vivo. We investigated differential mRNA expression in bovine intramuscular preadipocytes (BIPs) and bovine subcutaneous preadipocytes (BSPs) by culturing cells from the longissimus dorsi muscle and subcutaneous fat tissues of Luxi yellow cattle. The morphology of lipid accumulation of bovine preadipocytes was detected by Oil Red O staining, and total cholesterol (TC), low-density lipoprotein cholesterol (LDLC), and high-density lipoprotein cholesterol (HDLC) levels were measured. Temporospatial expression of HMGR was investigated by real-time quantitative polymerase chain reaction (PCR). The TC, LDLC, and HDLC content did not significantly differ over time but increased slowly with increasing MVA concentration. HMGR expression increased over time and with increasing concentrations of MVA. MVA increased adipose cell proliferation in a dose-dependent and time-dependent manner. MVA stimulated HMGR expression in two cell types and its influence on adipocyte differentiation.