a) The glycine conjugation pathway

Until recently, the extensive use of benzoate as a preservative was regarded as completely safe. All individuals will be exposed to a low level of benzoate generated by the gut microbes and present in berries and milk products. However, individuals that consume foods high in preservatives are exposed to large amounts of benzoate. A high dietary intake of benzoate has the potential to generate a shortage of glycine, which can have an impact on brain neurochemistry, and has also been associated with attention deficit-hyperactivity disorder in children. Benzoate effectively competes with salicylate for elimination resulting in the accumulation of salicyl-coenzyme A. Coenzyme A is then sequestered in the mitochondria, which disrupts ATP synthesis from pyruvate and fatty acids. When compared to other detoxification enzymes such as the cytochrome P450 enzymes, very little is known regarding the detoxification of benzoate and salicylate in vivo. Therefore, future studies in this field can be divided into three main avenues: i) Characterisation of the medium chain fatty acid: CoA ligases; ii) Characterisation of GLYAT and iii) Evaluation of the interaction and competition of various substrates metabolised by the glycine conjugation pathway.

The glycine conjugation pathway in felids is also very poorly characterised, with the majority of articles available, published before 1970. Interestingly, unlike all herbivores, felids do not have an orthologue for ACSM2B, which is the first step in the glycine conjugation pathway. This might explain why both benzoate and salicylate, which are detoxified by the glycine conjugation pathway, have been shown to be extremely toxic to cats. In future studies, we want to characterise the genetic and enzymatic variation of the glycine conjugation pathway in felids.

b) Development of molecular diagnostic methods for application in animal breeding

• Development and validation of non-invasive prenatal sexing of wildlife e.g. African Buffalo. 

Currently there is no standardised method for non-invasive fetal sex determination in wildlife. Knowing the sex of the fetus is important for the wildlife breeding industry as this will enable breeders to do better herd planning.

• Lovebirds

Wild type lovebirds are green. Due to mutation(s) in the gene that produces green pigment, this production is disrupted and the feathers are blue, aqua or turquoise. We propose to identify variants of genes that are linked to the blue series of lovebird plumage colours (blue, turquoise, aqua). Blue lovebirds are very popular among breeders, with individuals carrying these colour variants bringing in a higher price. The genetic markers coding for the blue colour series can be added to the parentage verification test (already developed and validated) to compile one single test allowing breeders to better select breeding birds.