Suitability of semen stress tests for predicting fertilizing capacity of boar ejaculates.

Besides classical semen parameters, semen stress tests (SSTs) are helpful tools to assess the fertilizing capacity of sperm. However, valid studies on SSTs in relation to fertility are rare because several corrections of common fertility parameters for female and male effects are required. Therefore, over a one-year period, we analyzed semen parameters of 260 ejaculates obtained from 130 Pietrain boars aged between 8 and 9 months in one AI center as well as 1521 corresponding insemination records for these ejaculates. Two consecutive ejaculates (4th and 5th) were collected from each boar and extended in DiluPorc™ BTS. In addition to routine semen evaluation, sperm motility was assessed after heat-resistance test (300 min incubation at 38 °C after seven days storage at 16 °C, HRT) and cold-resistance test (10 min incubation at 38 °C after three days storage at 6 °C, CRT). Generalized linear models (GLMs) were applied to analyze effects for the following predictors of farrowing rate (FR), number of total born (NTB) and live born (NLB) piglets: farm (P = 0.013 [FR], P = 0.001 [NTB], P = 0.023 [NLB]), parity (P = 0.679, P = 0.01, P < 0.001), weekday (P = 0.012, P = 0.08, P = 0.009) and year × season (P < 0.001, P = 0.688, P = 0.574). On boar level, GLMs revealed significant effects on FR, NTB and NLB for the predictors sow (all P < 0.001), total sperm number per dose (P = 0.007, P = 0.002, P < 0.001), total sperm motility (P = 0.002, P = 0.2, P = 0.003) and mitochondrial activity (P = 0.004, P < 0.001, P = 0.002). Moreover, FR and NTB were influenced by membrane integrity (both P < 0.001), FR and NLB by cold-resistance (P < 0.001, P = 0.043), and NTB and NLB by sperm morphology (P = 0.001, P < 0.001) and boar (both P < 0.001). NLB was additionally influenced by heat-resistance (P = 0.004) and farm (P = 0.018) and solely NTB was influenced by sperm output (P = 0.03). Boar and semen related factors explained 9% of the total variation in NTB and 7% of the total variation in NLB. Only 14.2% (n = 37) of the samples were both cold- and heat-resistant (≥65% of motile sperm). Cold- and heat-resistance were dependent factors (Chi-square, P = 0.001) and sperm motility after CRT and HRT showed a moderate positive correlation (rs = 0.40, P < 0.001, Spearman's rho). Finally, ROC curves demonstrated that neither SST can be used as a sole test for predicting the fertilizing capacity of boar ejaculates.

Obesity, insulin resistance, adiponectin, and PPAR-γ gene expression in broiler chicks fed diets supplemented with fat and green tea (Camellia sinensis) extract.

Adipose tissue is an active endocrine organ secreting several adipokines, especially adiponectin, that play an important role in regulating insulin function in the body of mammals. Therefore, this study was aimed to investigate the association between abdominal fat deposit, insulin resistance, peroxisome proliferator-activated receptor gamma (PPAR-γ), and adiponectin gene (AG) expression in broiler chicks fed diets high in unsaturated fat supplemented with green tea extract (GTE). A total of 300 one-day-old female Ross 308 broiler chicks were allocated to 6 dietary treatments in a completely randomized design with a factorial arrangement of two levels of GTE (0 and 500 mg/kg diet) × three levels of fat inclusion [without fat (control group), soybean oil (SO), and tallow (Ta)]. Each treatment was replicated five times. At the end of the experiment (day 49), two chicks from each replicate weighing an average of pen weight were bled and then slaughtered for further analysis. Abdominal fat percentage, fasting concentration of blood glucose, triglyceride and insulin, glycogen reserves of breast and liver tissues, and PPAR-γ and AG expression were determined. The insulin resistance index of the Quantitative Insulin Sensitivity Check Index (QUICKI) was calculated using the fasting plasma glucose and insulin concentrations. The highest abdominal fat percentage and the lowest carcass yield were obtained in chicks fed SO-supplemented diet (P < 0.05). Chicks fed diet supplemented with SO showed the highest PPAR-γ gene expression (P < 0.05). SO-rich diets suppressed AG expression in chickens' abdominal fat tissue, and the birds fed with SO-supplemented diet showed a significant decrease in AG expression compared with the control (P < 0.05). Chicks fed diet supplemented with SO showed lower QUICKI and breast glycogen reserve compared with the control group (P < 0.05). A significant increase in blood glucose and triglyceride concentrations was observed in birds fed SO-supplemented diets (P < 0.05). AG and PPAR-γ expression increased and decreased by GTE, respectively. QUICKI tended (P = 0.09) to be greater in GTE-supplemented chicks; however, the effect of GTE supplementation on carcass yield, abdominal fat percentage, and blood insulin and glucose concentration was not significant. The findings of this study showed that SO-rich diets via increased PPAR-γ gene expression and decreased AG expression in abdominal fat may lead to insulin resistance in female broiler chicks.

Enhanced performance of dye-sensitized solar cells based on TiO2 nanotube membranes using an optimized annealing profile.

We use free-standing TiO2 nanotube membranes that are transferred onto FTO slides in front-side illuminated dye-sensitized solar cells (DSSCs). We investigate the key parameters for solar cell arrangement of self-ordered anodic TiO2 nanotube layers on the FTO substrate, namely the influence of the annealing procedure on the DSSC light conversion efficiency. The results show that using an optimal temperature annealing profile can significantly enhance the DSSC efficiency (in our case η = 9.8%), as it leads to a markedly lower density of trapping states in the tube oxide, and thus to strongly improved electron transport properties.