Comparison between conjugated linoleic acid and essential fatty acids in preventing oxidative stress in bovine mammary epithelial cells

Some in vitro and in vivo studies have demonstrated protective effects of conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation. However, only a few and conflicting studies have been conducted showing the antioxidant potential of essential fatty acids. The objectives of the study were to compare the effects of CLA to other essential fatty acids on the thiol redox status of bovine mammary epithelia cells (BME-UV1) and their protective role against oxidative damage on the mammary gland by an in vitro study. The BME-UV1 cells were treated with complete medium containing 50 μM of cis-9,trans-11 CLA, trans-10,cis-12 CLA, α-linolenic acid, γ-linolenic acid, and linoleic acid. To assess the cellular antioxidant response, glutathione, NADPH, and γ-glutamyl-cysteine ligase activity were measured 48 h after addition of fatty acids (FA). Intracellular reactive oxygen species and malondialdehyde production were also assessed in cells supplemented with FA. Reactive oxygen species production after 3 h of H2O2 exposure was assessed to evaluate and to compare the potential protection of different FA against H2O2-induced oxidative stress. All FA treatments induced an intracellular GSH increase, matched by high concentrations of NADPH and an increase of γ-glutamyl-cysteine ligase activity. Cells supplemented with FA showed a reduction in intracellular malondialdehyde levels. In particular, CLA isomers and linoleic acid supplementation showed a better antioxidant cellular response against oxidative damage induced by H2O2 compared with other FA

Influence of short- and long-term exposure to a hot environment on rumen passage rate and diet digestibility by Friesian heifers.

Effects of short- and long-term exposure to a hot environment on diet digestibility and rumen passage rate were studied in four, 10-mo-old Friesian heifers housed in a climatic chamber. The trial lasted 65 d. Twenty-five days were spent under thermal comfort (temperature-humidity index = 64), and 40 d were spent under hot conditions (temperature-humidity index = 84). Three digestibility and rumen passage rate trials were performed during the 65 d. Chromium oxide was used as an external marker. The first digestibility and rumen passage rate trial (trial 1) was performed under thermal comfort; trials 2 and 3 were performed under hot conditions. Exposure to the hot environment reduced dry matter intake and increased water intake and rectal temperature compared with those during the thermal comfort period. Digestibility coefficients for dry matter, organic matter, neutral detergent fiber, and acid detergent fiber were higher in trial 2 than in trials 1 and 3. No statistical differences were found between trials 1 and 3 for these variables. Rumen passage rate was more rapid in trial 1 than in trials 2 and 3. No difference was observed between trials 2 and 3. These results indicated that exposure to a hot environment can affect digestibility in a time-dependent fashion, suggesting an adaptation of the digestive tract to hot environments

Heat shock induced changes of adipokines gene expression in 3T3-L1 adipocytes

To study the effects of heat shock on adipokines gene expression 3T3-L1 adipocytes were used. Heat shock differently affected gene expression of leptin, adiponectin and acylation stimulating protein (ASP): exposure of cells to temperature higher than 39°C caused upregulation of leptin and downregulation of adiponectin and ASP genes. The present study provides the first evidence about the effects of heat shock on adipokines gene expression. Changes in gene expression of the three adipokines may help to explain the alteration of lipid metabolism and liver functionality occurring in animals exposed to hot conditions

Report on relationships between THI and dairy cow performance

The work carried out under LiveM, L1.2 and described herein was based on construction and query of large databases which included multiannual productive and health field data. Productive data referred to dairy cows and included milk yield and composition, whereas health data were relative both to dairy cows and pigs. The analysis established the THI values above which a significant decline in the performance and health of dairy cows or pigs is to be expected. These results may help to adopt management environmental strategies which may permit to limit THI increase under farming conditions and/or to provide animals with interventions which may reduce heat load and/or increase dissipation of heat

Report on the analysis of interannual and seasonal variations in productive, reproductive and health data

The work carried out under LiveM, L1.2 and described herein was based on construction and query of large databases which included multiannual productive and health field data. Productive data referred to dairy cows, whereas health data were relative both to dairy cows and pigs. The analysis pointed out significant seasonal variations of parameters under study. In synthesis, summer/hot season was associated with significant worsening of dairy cows milk composition and with significant higher risk of death in pigs. These results may help to predict consequences of climate change in economically important sectors of the livestock industry and also to identify and target adaptation options that are appropriate for specific contexts, and that can contribute to environmental sustainability as well as to economic development