Technology: The sweet way to build a bigger pig

2019-02-28 05:05:09

PIG farmers could produce better, heavier animals that need fewer antibiotics with the help of a feed of combined sugars. The sugars work by nourishing beneficial bacteria that live in the pigs’ intestines. BioEurope, a French biotechnology firm, has developed the specialised food additive. It is a group of sugars which increase the pig’s weight at market by up to 9 per cent. The company says the sugars could replace the much-criticised antibiotics that farmers now feed routinely to livestock to boost growth. Farmed animals grow bigger and faster if they are fed antibiotics that work against a wide spectrum of bacteria, whether the animals are obviously sick or not. This practice, widespread among farmers, is thought to work by killing harmful gut bacteria, a source of much ill-health among crowded, stressed animals, though the drugs also kill beneficial bacteria. But the practice also breeds antibiotic-resistant bacteria, and leaves residues of the drugs in meat, much to the alarm of consumer groups. BioEurope describes its sugars as ‘pre-probiotics’. Probiotics are beneficial bacteria that normally inhabit the gut. Francois Paul, a researcher with BioEurope, says probiotics are beneficial to their host animals because they compete with coliforms and other bacteria such as Clostridium, which causes botulism and other infections. The probiotics reduce the numbers of such bacteria and help to digest some food, making more available for the animal. They can also stimulate macrophages, white blood cells in the gut which destroy harmful microorganisms. Some researchers have attempted to boost the numbers of probiotics in the gut by feeding them directly to animals – and humans – but their attempts have so far been disappointing, says Paul. He says, for example, that there is no evidence that the lactobacillus bacteria in live yoghurt join the colonies of similar bacteria already resident along the gut wall. BioEurope’s technique to boost probiotics involved designing a molecule that could survive its journey through the digestive tract to the colon, where the bacteria live. The molecule would then have to feed probiotics, but not harmful bacteria. The company’s researchers used enzymes that link sugars together in ways that cannot be broken down by digestive enzymes in the saliva, stomach or small intestine, to create various chains of the simple sugars sucrose and glucose, known as oligosaccharides. Next, the team fed the oligosaccharide to cultures of gut bacteria, and selected those chains which could be digested only by probiotics. The researchers then fed the oligosaccharides to pigs and compared the animals’ growth with that of pigs in the same barn that were fed none of the sugars. After three months – the normal fattening period for farmed pigs – those on the pre-probiotic were on average 6 kilograms heavier than the control pigs,