Assessing the viability of three Lactobacillus bacterial species protected in the cryoprotectants containing whey and maltodextrin during freeze-drying process.

Freeze-drying of bacteria associates with different stresses such as osmotic pressure, temperature and oxidation, and decreases bacterial viability, which seem to reduce by applying cryoprotectants. The present study evaluated the effect of four cryoprotectants on decreasing the stress caused by freeze-drying process among three Lactobacillus species. Additionally, it highlighted the use of whey and maltodextrin as a substitute for peptone and sucrose in cryoprotectants respectively. The viability of lactobacilli was measured after freeze-drying, 1 month of storage at 25 and 4°C. Based on the results, the viability rate of bacteria in protectants during freeze-drying stage was dependent on their strains. The best viability of Lacticaseibacillus rhamnosus GG and Ligilactobacillus salivarius 20687 was, respectively, observed in the protectants containing sucrose and whey, while Lactiplantibacillus plantarum NRRL B-14768 viability was equal in all protectants. The number of live bacteria reduced significantly by storing bacteria for 1 month at 25°C compared to the 4°C storage. During the storage period, the viability of L. salivarius improved by adding sucrose in protectant. Due to the positive effect of whey and sucrose in the drying and storage stage, on bacterial viability, the protectant consisting of whey and sucrose is suggested for all of the species under study.

Review of the relationship between milk urea nitrogen and days in milk, parity, and monthly temperature mean in Iranian Holstein cows.

The objectives of this study were to determine the relationships between milk urea N and days in milk, parity, and season in Iranian Holstein cows. Twelve Iranian commercial dairy herds participated in a 13-mo study from December 1, 2008, to December 31, 2009. All cows were milked 3 times daily, housed in freestalls, and fed a total mixed ration twice a day. Mean milk urea N over the study period was 16.0mg/dL. Mean milk urea N, categorized by 30-d increments of days in milk, paralleled changes in milk values and followed a curvilinear shape. However, milk urea N concentration reached a maximum at the fifth month of days in milk, but milk production reached a maximum at the third month. The concentration of milk urea N was lower during the first 30 d in milk category compared with all other days in milk categories. Overall mean milk urea N concentration of Holstein cows in the third and greater lactations was lower than in the first or second lactation. Milk urea N was at its lowest level in December (13 mg/dL), increased in the spring and summer months, and reached a maximum in July (18.8 mg/dL). From that point, milk urea N concentration progressively diminished to the autumn-winter level. In this study, milk urea N concentration was positively correlated with monthly temperature mean and may be a reason for the lower reproductive performance during the summer months. It has been recommended that milk urea N concentration should be evaluated in association with parity, days in milk, and season (or month). These variables should be considered potential sources of misinterpretation when exploring the relationship between milk urea N and nutritional management or measures of performance.

The amnesic effect of intra-central amygdala administration of a cannabinoid CB1 receptor agonist, WIN55,212-2, is mediated by a ß-1 noradrenergic system in rat.

In this study, we investigated effects of intra-central amygdala (intra-CeA) administrations of a cannabinoid agonist, WIN55,212-2 by itself and its interaction with ß1-adrenoceptor agents on memory consolidation. We used a step-through inhibitory avoidance (IA) task to assess memory in male Wistar rats. The results showed that post-training intra-CeA administrations of different doses of WIN55,212-2 at doses of 0.1 and 0.25 µg/rat impaired memory consolidation (or induced amnesia) as revealed by a decrease in step-through latency on the test day. Post-training intra-CeA injections of a ß1-adrenoceptor agonist, isoprenaline (0.01, 0.025, 0.05 µg/rat) by itself had no significant effect on memory consolidation, while at all doses prevented the amnesia induced by post-training injections of WIN55,212-2 (0.25 µg/rat). Although, post-training intra-CeA administrations of ß1-adrenoceptor antagonist, atenolol alone at different doses (0.01, 0.025, 0.05 and 0.1 µg/rat) had no significant effect, but its co-administrations at doses of 0.05 and 0.1 µg/rat along with an ineffective dose of WIN55,212-2 (0.05 µg/rat) induced amnesia, and at dose of 0.1 µg/rat along with an effective dose of WIN55,212-2 (0.25 µg/rat) increased amnesia that induced by the later drug. Moreover, the improving effect of isoprenaline (0.025 µg/rat) on amnesia induced by WIN55,212-2 (0.25 µg/rat) was prevented by intra-CeA co-injections of atenolol at doses of 0.01 and 0.025 µg/rat. The present results suggest that a ß1-adrenoeceptor mechanism in the central amygdala (CeA) is involved in amnesia induced by post-training intra-CeA injections of WIN55,212-2.