Bovine tuberculosis, a chronic and infectious disease that affects cattle, is a serious problem to farmers worldwide. The disease, in particular, is a top threat to the beef and dairy industry in the UK.
Addressing the disease involves controversial strategies, with the UK culling badgers to prevent the disease from being transmitted from wild animals to livestock.
A more feasible option for protecting the cattle from the disease may soon be available now that a group of researchers from China claims to have created genetically engineered cattle with more resistance to bovine TB.
The researchers came up with a process to insert a mouse gene dubbed SP110 into the genome of the Holstein-Friesian cattle. The gene has shown promise in controlling the bacterium known to cause bovine TB.
For their study published in the journal Proceedings of the National Academy of Science (PNAS) on Mar. 2, Haibo Wu from the Ministry of Agriculture in China and colleagues genetically altered 23 calves, 13 of which managed to survive into adulthood, using TALEN, a gene editing tool that allowed them to remove naturally occurring genes and insert new ones.
Wu and colleagues said that in laboratory tests, the bovine TB-causing bacterium called Mycobacterium bovis multiplied at a lower rate among the genetically modified cattle compared with the animals that were not genetically altered.
The researchers also infected three of the modified and three non-engineered animals with the bacterium. An analysis of the animals' organs after they were killed showed that the gene significantly reduced the infectious disease.
They likewise found that the engineered cattle were able to resist the bacterium in low dose when transmitted from infected cattle in natural circumstances. They have also noted that the cattle's offspring could inherit the gene and get protection from it.
"Our results contribute to the control and prevention of bovine tuberculosis and provide a previously unidentified insight into breeding animals for disease resistance," Wu and colleagues wrote in their study.
Experts said that the new research shows that genetic engineering could be successfully used to address animal disease, albeit the efficacy of the strategy employed in the new study still has to be determined.
"These findings are another step towards the creation of disease-resistant livestock animals based on advanced genetic tools," said Heiner Niemann, head of Germany's Institute of Farm Animal Genetics at Friedrich-Loeffler-Institut. "Whether this approach protects cows against TB infection when exposed to high doses of the pathogen remains to be determined."
