In cattle, as in other mammals, the genome is made up of several pairs of homologous chromosomes or autosomes (present in 29 pairs in cows) and a pair of sex chromosomes, X and Y. Females have two copies of the X chromosome, while males have one copy of each of the X and Y chromosomes. Females have 2 copies of the X chromosome, while males have one copy of each X and Y chromosome. Although it contains a large number of genes, the X chromosome is often overlooked in genomic studies, as it is present in only one copy in males. A team of INRAE and Eliance researchers from the Animal Genetics and Integrative Biology unit (GABI) has assessed the role of the X chromosome and the genes it harbors on key traits for the sustainability of cattle breeding. Their work, published in the journal BMC Genomics, reveals the importance of the X chromosome in the genetic determination of traits, and identifies the genes probably responsible for its effects.

The rumen microbiota plays an essential role in ruminant nutrition, degrading plant feed and transforming it into a source of energy and protein for the animal. In a collaborative review published in mSystems and coordinated by Rafael Muñoz-Tamayo of the UMR Modélisation Systémique Appliquée aux Ruminants - MoSAR (INRAE/AgroParisTech/UPSaclay, Palaiseau), the authors focused on the key rumen bacterium Fibrobacter succinogenes S85, which degrades cellulose and produces succinate.

The DGAT1 gene plays a major role in fat metabolism and triacylglyceride synthesis.

A new study, led by scientists from Uppsala University (Sweden) and the BREED Unit (Université Paris-Saclay/INRAE), has discovered that the pro-viral host protein ZC3H11A plays an essential role in maintaining the viability of embryos during early development. The study revealed a previously unknown function of ZC3H11A in the complex process of embryonic growth, and highlights its impact on development. The article is published in PNAS.

Teams from Ifremer and INRAE have just discovered two genes involved in resistance to nodavirosis, a disease that affects the brain of sea bass and causes major losses in Mediterranean fish farms. Following this discovery, published in the journal Genetics Selection Evolution, scientists and professionals from French sea bass hatcheries, which supply over 20% of the sea bass farmed in the Mediterranean (Italy, Greece, Turkey...), have launched a new project to select sea bass that are more resistant to this disease. This is a major challenge if we are to move towards more sustainable aquaculture.

In a study published in Microbes & Infection, researchers from the Infection et Immunité des Poissons team (Virologie et Immunologie Moléculaires - VIM unit, INRAE/UVSQ/UPSaclay, Jouy-en-Josas), in collaboration with INRAE's GABI and IERP units, have established a set of phenotypes linked to pathogenesis through the characterization of a collection of isogenic trout lines with contrasting resistance. Guided by the 3Rs principle, individual monitoring by non-lethal blood sampling has been applied for the first time in trout to monitor bacterial infection and host response; this approach makes it possible both to reduce the number of fish used and to increase the power of the experimental set-up.

Genetic diversity is the genetic variability between individuals in the same population or between populations. In the case of livestock, breeds are often equated with populations, and the diversity they contain is essential for their evolution and adaptation. However, breeding is about selecting the best individuals and therefore does not maintain the full diversity of animals. However, it is possible to freeze semen from bulls to preserve it and potentially use it later.

Parasites are known to influence various aspects of their host biology. Recent evidence shows that host microbiome modulation by infection is one of the strategies of vector-borne parasites to affect host immunity and physiology. Although avian malaria is a common disease affecting wild birds, very little information is available about its impact on the gut microbiome of wild birds. This is the first study testing wild bird gut microbiome modulation after experimental infection with avian malaria parasite.

A sytematic review of the litterature was done by a team of 20 scientists from 13 European countries using the on-line free tool, Cadima, containing 226 available publications. This systematic review was followed up with a meta-analysis using a Bayesian model including relevant covariables in order to create an age-dependent model for T. gondii prevalence in over 50 animal species. The results of this meta-analysis can be used to extrapolate data from regions where data are missing and to provide precious information for future approaches aimed at estimating the relative contribution of different sources of human infection by T. gondii.

Fish are exposed to large variations in the concentration of oxygen in their aquatic environment. When oxygen is depleted in relation to what is needed to maintain the energy metabolism of fish, this is called hypoxia. Hypoxia is one of the major threats to the aquaculture sector, causing substantial economic losses for fish farmers. It can strongly affect the health and welfare of fish, impacting on growth, reproduction, behaviour, immunity and other energy-demanding activities. Thus, improving hypoxia tolerance is of great economic and ethical interest to be included in aquaculture breeding programmes.