Antibiotics Could Increase Obesity, Say Researchers

 August 2012

US - Researchers at NYU School of Medicine have made a novel discovery that could have widespread clinical implications, potentially affecting everything from nutrient metabolism to obesity in children.

Since the 1950’s, low dose antibiotics have been widely used as growth promoters in the agricultural industry. For decades, livestock growers have employed subtherapeutic antibiotic therapy (STAT), not to fight infection or disease, but to increase weight gain in cattle, swine, sheep, chickens and turkey, among other farm animals.

First author Ilseung Cho, MD, MS, and colleagues set out to reveal how antibiotics were acting on the body to create this effect, hypothesizing that low doses of the drugs may alter the composition and function of the bacteria in the gut. The resulting study, appearing August 22 online ahead of print in Nature, confirmed their theory about the gut microbiome, the term used to refer to the community of bacteria that lives in the stomach, and raises new questions about how manipulating it can impact metabolism and disease in the body. 

The researchers administered STAT to normal mice and observed that the mice receiving antibiotics developed increased fat mass and percent body fat. After about six weeks, the mice that received antibiotics had gained about 10 to 15 per cent more fat mass than the mice that did not receive antibiotics. The researchers also noted that bone density was significantly increased in STAT mice early in development and that particular hormones related to metabolism were affected by antibiotic exposure, as well. 

Ventilation Reduces Environmental Impact

DENMARK - A new smart ventilation system helps Danish livestock producers to overcome some of the environmental challenges that the industry faces. Scientists from Aarhus University are involved in the development of the system devised by MT Højgaard Agri.

Unpleasant odours, ammonia emissions from livestock buildings and a high energy consumption pose significant environmental challenges for agriculture. In a new research project, scientists from Aarhus University are going to help develop a ventilation system which forms part of a new livestock housing concept designed by MT Højgaard Agri. The ventilation system reduces the environmental impact of livestock buildings by, among other things, reducing ammonia and odour emissions and lowering energy consumption.

"Emissions of CO2, ammonia, odour and dust are a permanent problem for the environment, for animal welfare and for the people working in the buildings. And this at the same time as agriculture is experiencing increasing demands for reductions in odour and ammonia emissions," says industrial post-doc Li Rong.

In addition to being a source of ammonia and odour, livestock buildings are also large consumers of energy, and 60 per cent of energy consumption in animal houses can be ascribed to ventilation and heating. The high energy consumption is detrimental both to the environment and to the farmer's economy.