Epigenetics and developmental programming of welfare and production traits in farm animals

The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the ‘developmental origins of health and disease’ or ‘DOHaD’ hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems

The synthetic enantiomer of pregnenolone sulfate is very active on memory in rats and mice, even more so than its physiological neurosteroid counterpart: Distinct mechanisms?

The demonstration that the neurosteroid pregnenolone sulfate (PREGS) is active on memory function at both the physiological and pharmacological levels led to us examining in detail the effects of the steroid on spatial working memory by using a two-trial recognition task in a Y-maze, a paradigm based on the natural drive in rodents to explore a novel environment. Dose–response studies in young male adult Sprague–Dawley rats and Swiss mice, after the postacquisition intracerebroventricular injection of steroid, showed an U-inverted curve for memory performance and indicated a greater responsiveness in rats compared with mice. Remarkably, the synthetic (−) enantiomer of PREGS not only also displayed promnesiant activity, but its potency was 10 times higher than that of the natural steroid. Intracerebroventricular coadministration experiments with dl-2-amino-5-phosphonovaleric acid, a competitive selective antagonist of the N-methyl-d-aspartate receptor, abolished the memory-enhancing effect of PREGS, but not that of the PREGS enantiomer, evoking enantiomeric selectivity at the N-methyl-d-aspartate receptor and/or different mechanisms for the promnestic function of the two enantiomers