Use of assisted reproductive technologies (ARTs) to shorten the generational interval in ruminants: current status and perspectives.

The challenges posed by climate change and increasing world population are stimulating renewed efforts for improving the sustainability of animal production. To meet such challenges, the contribution of genomic selection approaches, in combination with assisted reproductive technologies (ARTs), to spreading and preserving animal genetics is essential. The largest increase in genetic gain can be achieved by shortening the generation interval. This review provides an overview of the current status and progress of advanced ARTs that could be applied to reduce the generation time in both female and male of domestic ruminants. In females, the use of juvenile in vitro embryo transfer (JIVET) enables to generate offspring after the transfer of in vitro produced embryos derived from oocytes of prepubertal genetically superior donors reducing the generational interval and acceleration genetic gain. The current challenge is increasing in vitro embryo production (IVEP) from prepubertal derived oocytes which is still low and variable. The two main factors limiting IVEP success are the intrinsic quality of prepubertal oocytes and the culture systems for in vitro maturation (IVM). In males, advancements in ARTs are providing new strategies to in vitro propagate spermatogonia and differentiate them into mature sperm or even to recapitulate the whole process of spermatogenesis from embryonic stem cells. Moreover, the successful use of immature cells, such as round spermatids, for intracytoplasmic injection (ROSI) and IVEP could allow to complete the entire process in few months. However, these approaches have been successfully applied to human and mouse whereas only a few studies have been published in ruminants and results are still controversial. This is also dependent on the efficiency of ROSI that is limited by the current isolation and selection protocols of round spermatids. In conclusion, the current efforts for improving these reproductive methodologies could lead toward a significant reduction of the generational interval in livestock animals that could have a considerable impact on agriculture sustainability.

Heavy Metal(loid) Accumulation in the Ovarian Tissue of Free-Ranging Queens and Bitches Inhabiting Highly Polluted Urban Environments.

There is strong scientific evidence that exposure to environmental contaminants, such as heavy metal(loid)s (HMs), can impair female reproductive function. Pets, such as cats and dogs, who share the same habitat as humans, may be particularly useful sentinel models for detecting HMs in the ovary. In the present study, we compared the concentration of essential (Ems; Cu, Fe, Mn, Se, and Zn) and non-essential metal(loid)s (NEMs; Al, As, Cd, and Pb) in the ovarian tissues of free-ranging queens and bitches of different ages living in industrialized/highly polluted (south group) and non-polluted (north group) urban areas of the island of Sardinia, Italy. The results showed that both EMs and NEMs were present at detectable concentrations in feline and canine ovaries and their levels varied according to geographical areas and animal age. Among the EMs, Cu was found elevated in older queens and bitches inhabiting the southern area. Cadmium and lead were higher in feline and canine ovaries of older animals from the south compared to those living in the north. In addition, Cd and Pb concentrations increased in individuals of both species living in the south. These findings showed new perspectives for the use of pets as early warning sentinels of environmental pollution by HMs and for the risk of human exposure within a "One Health" approach. Pets may help to study the link between exposure to metals and female reproductive disturbances in mammals.

Shift in Circulating Serum Protein Fraction (SPF) Levels of Pregnant Jennies and Nutritional Related Aspects at Early-, Mid- and Late Gestation.

A viable tool for the monitoring of the systemic condition of the pregnant jenny may be the determination of serum protein fraction (SPF) levels, including metabolic profiling. Tissue development and composition of the growing fetus requires the mother to provide adequate nutrients to its body parts and organs. In this regard, body fluid distribution and strategic molecule transportation can be screened using SPF electropherograms and analysis of intermediate metabolites. The nutritional and health status of 12 jennies (age: 5-8 years; BW at the start: 135-138 kg; Body Condition Score, BCS [1 to 5 points] = 2.25-2.50; 4th month of gestation) were monitored throughout gestation (approximate gestation period 350-356 d). All animals were pasture-fed and were offered hay ad libitum. Individual blood samples were collected within the 4th, 7th, and 10th month following conception (ultrasound scanning). Serum biochemistry, in particular, the analysis of 6 fractions of serum proteins was carried out. The significant decrease in circulating albumin in jennies from mid- to late-gestation (p < 0.001) suggests a considerable role of dietary amino acids in the synthesis of protein for fetal tissue formation as well as body fluid distribution and blood pressure control of the jenny in those stages. Moreover, α1-globulin decreased significantly in late gestation (p < 0.047), corresponding to major organ development in the terminal fetus and supported by lipid transportation in the bloodstream of the jenny. Similarly, α2-globulin decreased in late gestation (p < 0.054) as haptoglobin, an important component for the transport of free circulating hemoglobin, is likely used for fetal synthesis. Mid-gestation, appears to be a crucial moment for adequate dietary nutrient supplementation in order to prevent homeostasis perturbation of jennies, as observed in this trial.

Artifacts and Technical Restrictions in 2D Shear Wave Elastography.

2 D shear wave elastography (2D-SWE) is the latest evolution of elastography techniques and allows real-time quantitative assessment of the medium stiffness. The aim of this review is to identify, describe, explain and illustrate some technical restrictions and artifacts in 2D-SWE. Encountered artifacts and technical restrictions may be categorized according to acquisition technique, medium, or operator: · Acquisition technique: B-mode & SWE entanglement, transducer frequency, posterior elastographic shadowing artifact, mirrored elastogram artifact, "vertical striped" artifact, resolution limits in SWE, non-equivalence of elastographic devices. · Medium: SWE in liquid medium, "black hole phenomenon", pseudo-liquid lesions, musculotendinous anisotropy, intrinsic stiffness variations of tendons and muscles, depth of analysis, movement artifacts. · Operator: Region of interest compression, acquisition and measurement parameters (ROI size, ROI location, elastogram acquisition time). Clear knowledge of the underlying physical basis is necessary in 2D-SWE because radiologists have to deal with technical restrictions and a wide range of artifacts. Proper use of 2D-SWE ensures the reliability and reproducibility of the technique.

Ultrasound elastography in tendon pathology: state of the art.

Elastography assesses the biomechanical and structural properties of tissues by measuring their stiffness. Despite promising results, elastography has not yet earned its place in the daily practice of musculoskeletal radiologists. The purpose of this article is to present and examine the data available to date on ultrasound elastography of the tendons through a review of the literature to provide musculoskeletal radiologists with an overview that may help them better understand and use elastography routinely. The most common techniques in ultrasound elastography are described. Then, the aspects of the physiologic and pathologic tendon are presented and discussed. One must make this technique one's own to better apprehend its contribution to the musculoskeletal imaging field, while bearing in mind that further research will be required before admitting elastography as a reliable and validated tool able to optimize our daily clinical practice.