Feed Management - May 2016 - 7
FeedManagement ❙ 7 positively associated with digestive disorders and scours. An overload of feed, especially of low digestibility, usually overwhelms the immature digestive system, especially if gastrointestinal health has been impaired due to anorexia during the first couple of days post-weaning. To this end, it is imperative to ensure piglets exhibit high levels of feed intake immediately post-weaning or their feed intake must be controlled during the first week. Closing, it is also interesting to note that vaccinations that often occur at the time of weaning may be responsible for reduced feed intake during the first week post-weaning. This is because vaccinations often cause a (natural and expected) mild inflammation (as a result of the immune system stimulation to produce antibodies as a result of vaccination) that invariably reduce feed intake and growth rates. Such effect has been demonstrated in trials and it is often observed between the third and fifth day post-weaning - especially in piglets without prior access to high-quality creep feed. Gut immunity is a daily challenge Sow's colostrum provides the first wave of passive immunity through the absorption of intact immunoglobulins in to the bloodstream. This protective action of colostrum is effective only against pathogens to which the sow has been exposed. Mature milk is also a rich source of immunoglobulins, especially IgA, which act locally at the luminal level. Milk immunoglobulins provide a constant protective barrier against pathogenic invasion, and they also bind and inactivate antigens directly. The "mammary link" also ensures a rapid transfer of antigen-programmed lymphocytes from the sow's gut directly to the mammary gland, where they produce relevant immunoglobulins immediately available for the suckling piglet. After weaning, the passive protection from sow's milk is withdrawn and the young piglet depends solely on any active (self) immunity developed during suckling. Active immunity develops slowly and depends on lactation length and level of exposure to pathogenic organisms. A change of environment and exposure to new pathogens virtually eliminates any benefits from active immunity acquired during suckling. At weaning, major May/June 2016 ❙ www.WATTAgNet.com alterations in intestinal immunity are observed during the first 24 hours. The activation of the immune system at weaning is followed by systemic and local inflammatory reactions, which gear metabolism away from growth and development. Gastrointestinal inflammation also compromises the protective functions of mucosal epithelial barrier and increases sensitivity to dietary antigens; thus, minimizing activation of the immune system remains a major goal in early weaning systems. LEARN MORE: How liquid feeding improves piglet gut health, www.WATTAgNet.com/158078.html In support of gut immunity during the post-weaning period, in-feed sources of immunoglobulins (colostrum, plasma, egg antibodies) are highly prized, but with quality comes high cost that must be balanced by increased gut health and ultimately improved growth performance. In fact, this is invariably the case, hence the widespread use of in-feed immunoglobulins worldwide. Intestinal bacteria The sterile gastrointestinal system of the newborn piglet is quickly colonized by a host of maternal and environmental bacteria. Nevertheless, the establishment of a healthy intestinal microflora is a gradual process affected by several ill-defined factors including nutrition and immunity status. The presence of intestinal bacteria has significant effects on intestinal development and function. Compared to germ-free animals, the presence of a normal bacterial population in conventionally raised piglets increases gut mass, reduces villous height, and increases crypt depth. Germ-free and antibiotic-treated animals also have greater digestive enzyme activity. The effects of intestinal bacteria on gut morphology and function appear to be superimposed on any adaptive responses to dietary changes, and thus maintaining piglets in a healthy environment will always reduce the impact of drastic dietary interventions. Intestinal bacteria growth is always at the expense
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.