102,374 research outputs found
METABOLIC EFFECTS AND REPRODUCTIVE PERFORMANCES IN DAIRY COWS TREATED WITH A FUNCTIONAL FEED (NAT®W3)
No full textThe Authors investigated to correlate metabolic efficiency to reproductive performances by the administration of functional feed in high-producing dairy cattle. The trial want to study, also, the capability of laboratory diagnostic in evaluation and estimation of the reproductive capacities to select subjects to submit to reproductive praxis.
Functional feed contains vitamins E, A, D3, organic-selenium, polyinsaturated fatty acids (PUFA) and a prebiotic by fermented cereals. Effects of PUFA administered were particularly investigated in lipoprotein fractions composition, in blood. Optimal relationship among LDL-cholesterol, total cholesterol and progesteron was related to best reproductive performances: in this trial. Authors can confirm this on the basis of livestock performances. Study realized during the most worm period of the year when mean daily temperature go up to 30°C.
Metabolic parameters considered are linked to energetic, mineral and endocrine metabolisms. Determination were realized in blood-samples before, during, after the administration of NAT3. Bovines were fed with different addition of NAT3 (320-360 g/subj/die) for 4 months.
Reproductive indices studied were: open-days and number of services per conception.
Trend analysis of fertility indices demonstrated that blood levels of progesterone and blood antioxidant capability are strictly correlated and correlated also to reproductive performances.
Efficacy of treatment is demonstrated by the trend of the fertility indices in the post treatment period during which indices return progressively to the pre treatment values in about 60 days: this period correspond to the lipid tissue turnover time. During these days a temporary build-up of PUFA and liposoluble vitamins was observed.
Blood progesterone levels were higher (2.2 times) in correspondence of the 21st day post partum in treated subjects respect to control ( 0.18 vs 0.44 ng/l). Reproductive indexes recorded stressed that open-days varied from to . Number of services per conception was reduced from 121 to 95 at 60th day of treatment. In the next four months the value of the index settled between 90-95 days.
Data obtained in this study show that administration of PUFA, antioxidants and probiotics administred in dairy cows can remodel metabolisms correlated to fertility such as progesterone, prostaglandins and prostacyclins synthesis. These evidences are stressed by trends recorded in the herd concerning values of open-days and the number of services per conception
Polychlorinated biphenyl (PCB) anaerobic degradation in marine sediments: microcosm study and role of autochthonous microbial communities
No full textPolychlorobiphenyl (PCB) biodegradation was followed for 1 year in microcosms containing marine sediments collected from Mar Piccolo (Taranto, Italy) chronically contaminated by this class of hazardous compounds. The microcosms were performed under strictly anaerobic conditions with or without the addition of Dehalococcoides mccartyi, the main microorganism known to degrade PCBs through the anaerobic reductive dechlorination process. Thirty PCB congeners were monitored during the experiments revealing that the biodegradation occurred in all microcosms with a decrease in hepta-, hexa-, and penta-chlorobiphenyls (CBs) and a parallel increase in low chlorinated PCBs (tri-CBs and tetra-CBs). The concentrations of the most representative congeners detected in the original sediment, such as 245-245-CB and 2345-245-CB, and of the mixture 2356-34-CB+234-245-CB, decreased by 32.5, 23.8, and 46.7 %, respectively, after only 70 days of anaerobic incubation without any bioaugmentation treatment. Additionally, the structure and population dynamics of the microbial key players involved in the biodegradative process and of the entire mixed microbial community were accurately defined by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) in both the original sediment and during the operation of the microcosm. The reductive dehalogenase genes of D. mccartyi, specifically involved in PCB dechlorination, were also quantified using real-time PCR (qPCR). Our results demonstrated that the autochthonous microbial community living in the marine sediment, including D. mccartyi (6.32E+06 16S rRNA gene copy numbers g−1 sediment), was able to efficiently sustain the biodegradation of PCBs when controlled anaerobic conditions were imposed. © 2015, Springer-Verlag Berlin Heidelberg
Validazione di una metodica di analisi in spettrofotometria AA per il Vanadio in matrici biologiche
No full text
Predictive value of oocyte morphology in human IVF: a systematic review of the literature
No full textBackground: Non-invasive selection of developmentally competent human oocytes may increase the overall efficiency of human assisted reproduction and is regarded as crucial in countries where legal, social or religious factors restrict the production of supernumerary embryos. The purpose of this study was to summarize the predictive value for IVF success of morphological features of the oocyte that can be obtained by light or polarized microscopic investigations.
Methods: Studies about oocyte morphology and IVF/ICSI outcomes were identified by using a systematic literature search.
Results: Fifty relevant articles were identified: 33 analysed a single feature, 9 observed multiple features and investigated the effect of these features individually, 8 summarized the effect of individual features. Investigated structures were the following: meiotic spindle (15 papers), zona pellucida (15 papers), vacuoles or refractile bodies (14 papers), polar body shape (12 papers), oocyte shape (10 papers), dark cytoplasm or diffuse granulation (12 papers), perivitelline space (11 papers), central cytoplasmic granulation (8 papers), cumulus-oocyte complex (6 papers) and cytoplasm viscosity and membrane resistance characteristics (2 papers). None of these features were unanimously evaluated to have prognostic value for further developmental competence of oocytes.
Conclusions: No clear tendency in recent publications to a general increase in predictive value of morphological features was found. These contradicting data underline the importance of more intensive and coordinated research to reach a consensus and fully exploit the predictive potential of morphological examination of human oocytes
Open versus closed systems for vitrification of human oocytes and embryos
No full textVitrification is now the dominant approach for cryopreservation of human oocytes and embryos; however, serious disagreement persists, particularly about biosafety issues. Techniques are categorized as either 'open' or 'closed' according to occurrence of direct contact between the medium and liquid nitrogen during cryopreservation. Advocates of closed systems emphasize the potential danger of disease transmission mediated through liquid nitrogen, and praise the safety of their approach; those who use the open systems refer to the lack of evidence of disease transmission and regard their systems as more consistent and efficient. The purpose of this review is to clarify whether open and closed systems are really open and closed; if closed systems are safe and free of any danger of contamination; if closed systems are equally efficient as open ones for cryopreservation of human embryos and oocytes by considering overall outcome; and finally, if ethical and legal concerns are sound when risks and benefits are considered in a broader sense. On the basis of these answers, implementation of rational measures to lower the theoretical danger of disease transmission are proposed while maintaining the achievements in cryopreservation that have contributed substantially to the advancement in assisted reproduction techniques during the past decade
Impact of Maternal Age on Oocyte and Embryo Competence
No full textThe overall success of human reproduction, either spontaneously or after IVF, is highly dependent upon maternal age. The main reasons for age-related infertility include reduced ovarian reserve and decreased oocyte/embryo competence due to aging insults, especially concerning an increased incidence of aneuploidies and possibly decreased mitochondrial activity. Age-related chromosomal abnormalities mainly arise because of meiotic impairments during oogenesis, following flawed chromosome segregation patterns such as non-disjunction, premature separation of sister chromatids, or the recent reverse segregation. In this review, we briefly discuss the main mechanisms putatively impaired by aging in the oocytes and the deriving embryos. We also report the main strategies proposed to improve the management of advanced maternal age women in IVF: fertility preservation through oocyte cryopreservation to prevent aging; optimization of the ovarian stimulation and enhancement of embryo selection to limit its effects; and oocyte donation to circumvent its consequences
The Impact of Unbalanced Maternal Nutritional Intakes on Oocyte Mitochondrial Activity: Implications for Reproductive Function.
No full textAbstract
Accumulating evidence on the effect of nutrition on reproduction is emerging from both animal and human studies. A healthy dietary pattern and nutrient supplementation, especially during the peri-conceptional period, might be helpful to achieve a live birth, although the mechanisms implicated are not fully understood. The endocrine system and the ooplasmic organelles apparatus, in particular the mitochondria, are clearly key elements during oogenesis and subsequent embryo development, and their proper functioning is associated with nutrition, even beyond maternal aging. Several studies in animal models have reported various adverse effects on mitochondria caused by unbalanced dietary intakes such as high fat diet, high fat high sugar diet, and low protein diet. The alterations produced might include mitochondrial intracellular distribution, content, structure, biogenesis, and functioning. This review summarizes the key role of mitochondria in female reproduction and the effects of different dietary macronutrient compositions on oocyte mitochondrial activity with their possible short-, medium-, and long-term effects
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