The 3 pillars of successful piglet rearing

Swine producers constantly have to produce pigs more sustainably, achieve higher welfare standards and be more cost-effective. While demands increase, tools such as antibiotics and zinc oxide are being restricted due to the threat of antibiotic resistance. Advances in genetics have led to hyper-prolificacy in sows, which presents additional challenges, as do increases in price and decreases in availability and quality of raw materials.

Optimising piglet care is critical to meeting these challenges. There are 3 pillars of successful piglet rearing:

1. Properly preparing the piglet for pre- and post-weaning challenges;

2. Protecting the gut in the immediate post-weaning period; and

3. Supporting resilience of the weaned pig to ensure it can to combat future challenges.

Pillar 1: Prepare the piglet

The first week of a piglet’s life is critical in dictating its future health and productivity. During these first few days, the gut develops rapidly, increasing both digestive and absorptive capacity. In parallel, microbes are colonising the gut, shaping the composition of the gut microbiome and driving the development of the gut-associated lymphoid tissue, home to more than 70% of the piglet’s immune cells. One of the most powerful, sustainable and often overlooked strategies for supporting a piglet in early life is developing its own immune competency.

Immune competency development

A piglet’s immune competency development begins in utero and continues when it ingests passive immunity received from the sow via colostrum and milk. Recent research has demonstrated that the gut microbiome plays a pivotal role in priming the development of the gut and immune system. To best prepare a piglet for the challenge of weaning and beyond, promote immune competency development via 2 paths:

• Systemically, enhancing the quality of passive immunity received from the sow; and

• Locally, via modulation of the gut microbiome to prime the development of the mucosal immune system.

Sow nutrition and health

Central to effective systemic immune competency development of a piglet is the sows’ nutrition and health and the ability to transfer protection to the piglet. Micronutrients, including some vitamins (D3, E, C and B) and minerals, have immunomodulatory benefits. Piglets are born with low levels of blood vitamins, and the high demands on these vitamins often result in deficiency. Hyper-prolificacy places greater demands on the sow to rear large, uniform litters. These necessitate a more precise micro-nutrition approach during late gestation and lactation to support optimum colostrum quality and yield.

Micro-organisms

Local immune competency begins when the piglet leaves the sterile conditions of the uterus and is exposed to numerous micro-organisms. The microbiome of the sow and her immediate environment largely influence the development of the piglet gut microbiome. Therefore, influencing the microbiome of the sow during gestation and lactation via probiotics such as Enterococcus faecium and improving fibre digestibility and the associated microbiome changes through use of xylanases are effective strategies for optimising the piglet microbiome. Developing and maintaining a stable and diverse gut microbiome in the piglet is critical to pathogen resilience and optimum functioning of the gut in an environment of reduced medication.

Pillar 2: Protect the piglet

Supporting the piglet at weaning starts with protecting the gut, which provides 4 important functions: regulating nutrient and fluid uptake, managing immune tolerance, defending against infections and providing a barrier to the external environment. Unlike in nature where the piglet has a prolonged weaning and gradually develops these gut functions, in commercial production, weaning is an abrupt 1-day event.

Leaky-gut syndrome

Any disruption to the development of the gut function can significantly impact the lifetime performance of the pig, and the most common observed outcome of abrupt weaning is leaky-gut syndrome. Leaky-gut syndrome is characterised by hyper-permeability of the intestinal epithelium.

The tight junction failure allows pathogens to adhere to the intestinal cells, culminating in water and electrolyte loss, leading to diarrhoea. In addition to diarrhoea, other visible signs of the enteric infection include reduced feed intake, weight loss, fever, poor feed efficiency and lack of uniformity.

Underlying impact on the immune system

What is not visible is the underlying impact on the immune system that the infection triggers. The heightened immune response significantly increases demand for nutrients such as amino acids, vitamins, minerals, antioxidants and lipids. Often, muscle tissue is broken down to support this immune response.

Direct and indirect factors

The severity of leaky-gut syndrome is impacted by direct and indirect factors. Direct factors include allergens and antigens that activate the pro-inflammatory cytokine cascade that causes gut inflammation. Allergens can originate from feed, most commonly soybean meal. Antigens, too, originate from feed and include components such as mycotoxins, but can also originate in the gut lumen from cellular debris (peptidoglycans) originating from cell walls of dead gram-positive bacteria.

Growth of pathogens

Indirect factors contributing to the severity of leaky gut are the facilitators of the gut environment that support the growth of pathogens. An abundance of undigested nutrients, particularly protein (often as a result of protease inhibitors in soybean meal and the presence of phytates in the diet) and the presence of viscous fibre will support pathogen growth. Similarly, a neutral pH environment will favour pathogen proliferation rather than pathogen inhibition. Therefore, there are 2 strategies central to protecting piglets and reducing leaky gut syndrome:

1. Deactivate the antigens and allergens that trigger a pro-inflammatory cytokine cascade through targeted use of proteases, mycotoxin deactivators and muramidase to cleave the peptidoglycans in bacterial cell wall debris;

2. Create a less favourable environment for pathogen growth through use of proteases, carbohydrases and phytases to degrade undigested feed components that pathogens grow on, and use an ultra-pure benzoic acid to change the pH of the gut to favour inhibition of pathogens.

Pillar 3: Support resilience

Resilience refers to the ability of the pig to recover from a challenge and return to reaching its genetic potential. A resilient pig is well equipped to combat future challenges, and studies have shown that any decrease in performance in the early stages post-weaning can significantly compromise performance in the growing-finishing phase.

Health, immune competency and gut functionality

How quickly a pig recovers from a challenge is related to the health, immune competency and gut functionality of the pig and is why optimisation detailed in the prepare and protect pillars is so important. A key aspect of resilience is understanding that the immune system needs a different suite of nutrients, especially amino acids, required for lean muscle accretion. Supporting resilience therefore relies on 2 components, ensuring:

• the optimal extraction of nutrients from the feed (optimum nutrient digestive efficiency – the pre-absorptive component); and

• the appropriate allocation of nutrients to maintenance and production (the post-absorptive component).

Maximum feed digestibility

The key in the pre-absorptive phase of nutrient utilisation is ensuring that feed digestibility is maximised so the pig can extract maximum value from its feed. Digestibility can be maximised via 2 main mechanisms:

• ensuring fibre, protein and starch are fully utilised through strategic use of targeted exogenous enzymes; and

• removing bacterial cell debris (such as peptidoglycans) from the intestinal surface using a muramidase so that the digested nutrients are available for absorption.

Building resilience

Supporting post-absorptive resilience requires effective transfer of nutrients to productive purposes such as lean muscle deposition, with limited diversion of nutrients to maintenance and unproductive inflammatory responses. Strategies to reduce the inflammatory processes, introduced above, are essential for building resilience. Carbohydrases release nutrients in the pre-absorptive phase and also play a pivotal role in improving the hindgut fermentation of dietary fibre, unlocking energy reserves and producing short chain fatty acids that support colonocyte health.

Effective mineral nutrition is also key to supporting resilience. Reducing the negative effects of phytate on nutrient binding can increase mineral availability. Phytase also has additional effects on animal performance, beyond the phosphorus effect, at the post-absorptive level.

Conclusions with regard to piglet rearing

DSM recognises the importance of piglet health in meeting the challenges faced by pork producers. By preparing the piglet through immune competency development, protecting the piglet by optimising gastrointestinal functionality and supporting resilience through optimised digestive efficiency, producers will be well positioned for a sustainable, productive and profitable herd.

By Neil Gannon, PhD, global swine technical manager at DSM Animal Nutrition & Health