Figure 2.

Factors affecting the gut microbiota in pigs. The diversity of gut microflora can be affected by a variety of factors. Sub-therapeutic doses of antibiotics used in commercial farming can negatively affect the microbiota. Similarly, different stressors such as high temperature, transportation, weaning, and overcrowding can also change the diversity of the microbiota for the worse. The inclusion of probiotics, prebiotics, and fiber appear to nullify these effects and improve diversity. Other factors, such as the age of the animal, its mode of the birth, breed and the environment it lives in, can influence the microbiota. Potentially pathogenic microbes are depicted in red and beneficial (and other commensals) microbes in green. The red arrows indicate a negative impact and a green arrow a positive impact. The gray arrows are an indication that different factors can affect the microbiota differently, either positively (e.g., if animals are bred in a healthy, growth-conducive environment) or negatively (e.g., following cesarean birth, devoid of any natural mother’s microbiota).