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

Developments of reproductive management and biotechnology in the pig

This review aims to describe changes in production environment, management tools and technology to alleviate problems seen with the present hyperprolific sow model. Successful parturition in the pig includes the possibility to express adequate maternal behaviour, rapid expulsion of piglets, complete expulsion of placenta, elimination of uterine contamination and debris, neonatal activity and colostrum intake. We focus on management of large litters, including maternal behaviour, ease of parturition, colostrum production, piglet quality parameters and intermittent suckling. There are also some interesting developments in technology to assess colostrum and immune state of the piglet. These developments may be utilized to improve the success rate of reproductive management around farrowing, lactation and after weaning. We also discuss new insights in how to examine the health of the mammary gland, uterus and ovaries of hyperprolific sows. Finally, we assess the latest developments on breeding and technology of hyperprolific sows, including artificial insemination (AI), real-time ultrasound of the genital tract and embryo transfer (ET). We conclude that 1) for the sow to produce sufficient colostrum, both the behavioural and physiological needs of the sow need to be met before and after parturition. Furthermore, 2) new ultrasound and biopsy technology can be effectively applied for accurate diagnosis of inflammatory processes of the udder and uterus and timing of AI regarding ovulation to improve insemination efficiency. Finally, 3) developments in cryopreservation of germ cells and embryos appear promising but lack of valid oocyte collection techniques and nonsurgical ET techniques are a bottleneck to commercial ET. These latest developments in management of parturition and reproductive technology are necessary to cope with the increasing challenges associated with very large litter sizes.Peer reviewe

Short-chain fructo-oligosaccharides supplementation to suckling piglets : assessment of pre- and post-weaning performance and gut health

Farmers face difficulties in redeeming their investment in larger litter sizes since this comes with larger litter heterogenicity, lower litter resilience and risk of higher mortality. Dietary oligosaccharides, given to the sow, proved beneficial for the offspring's performance. However, giving oligosaccharides to the suckling piglet is poorly explored. Therefore, this field trial studied the effect of dietary short-chain fructo-oligosaccharides (scFOS; 1g/day; drenched) supplementation to low (LBW, lower quartile), normal (NBW, two intermediate quartiles) and high (HBW, upper quartile) birth weight piglets from birth until 7 or 21 days of age. Performance parameters, gut microbiome and short-chain fatty acids profile of feces and digesta were assessed at birth (d 0), d 7, weaning (d 21.5) and 2 weeks post-weaning (d 36.5). Additional parameters reflecting gut health (intestinal integrity and morphology, mucosal immune system) were analysed at d 36.5. Most parameters changed with age or differed with the piglet's birth weight. Drenching with scFOS increased body weight by 1 kg in NBW suckling piglets and reduced the post-weaning mortality rate by a 100%. No clear difference in the IgG level, the microbiota composition and fermentative activity between the treatment groups was observed. Additionnally, intestinal integrity, determined by measuring intestinal permeability and regenerative capacity, was similar between the treatment groups. Also, intestinal architecture (villus lenght, crypt depth) was not affected by scFOS supplementation. The density of intra-epithelial lymphocytes and the expression profiles (real-time qPCR) for immune system-related genes (IL-10, IL-1ss, IL-6, TNF alpha and IFN gamma) were used to assess mucosal immunity. Only IFN gamma expression, was upregulated in piglets that received scFOS for 7 days. The improved body weight and the reduced post-weaning mortality seen in piglets supplemented with scFOS support the view that scFOS positively impact piglet's health and resilience. However, the modes of action for these effects are not yet fully elucidated and its potential to improve other performance parameters needs further investigation

Effects of low litter birth weight on the pathogenesis of influenza A virus following experimental infection

A fetus’ in utero environment has a profound effect on the individual’s development in postnatal life. Research has suggested that intrauterine growth restricted children have a less robust response to vaccination. Studies have confirmed similar results in animal models; however, the effect of low birth weight on clinical disease expression is unclear. This research aims to determine if pigs from low birth weight litters have increased severity of disease after experimental infection with influenza A virus (IAV) when compared to their counterparts from high birth weight litters, thus clarifying the effect of litter birth weight on disease expression. Pilot trials were conducted to determine the appropriate dose of virus to use and the optimal days post inoculation for necropsy to use for the main trial. The results indicated that the main trial should use an inoculation dose of 1 x 107 plaque forming units of IAV and the time of necropsy should be 48 hours post inoculation. In the main trial, male piglets (n=68) from parity one or two sows were identified at farrowing as coming from high or low birth weight litters. At four weeks of age, intratracheal IAV inoculation was performed (day 0) and pigs were euthanized at 48 hours post inoculation. Clinical signs were assessed prior to euthanasia. After euthanasia macroscopic and microscopic lesion severity were assessed, along with immunohistochemical staining intensity of IAV in lung tissue. SearchLight Chemiluminescent Array Technology was used to measure the concentration of the inflammatory cytokines interleukin 1 beta, interleukin 6, and interleukin 8 in bronchoalveolar lavage fluid. Interferon alpha was measured using fluorescent microsphere immunoassay. Fifty Percent Tissue Culture Infective Dose was used to measure influenza viral titers in lung tissue. The study found no differences in clinical scores or cytokine concentration between pigs from high and low birth weight litters. Gross, histopathological and immunohistochemical scores were significantly higher in piglets from high birth weight litters and viral titers trended higher in these piglets. These findings indicate that pathologic disease scores in piglets experimentally inoculated with IAV are more severe in piglets from high birth weight litters