Intestinal challenges are a common cause of production losses during the post-weaning period. Damage to the intestinal barrier caused by pathogens reduces health and absorption of nutrients. It is well known that antibiotics inhibit growth of certain pathogenic microorganisms and can be used to boost piglet performance. However, the demand for antibiotic-free pork and the reduction of antibiotics as growth promoters in pig production creates a need for holistic approaches to sustain intestinal health and thriving piglets, even in the absence of antibiotics.
In spite of this reduction in antibiotic use, there are strategies that can be used to lower the intestinal challenges that piglets encounter after weaning and maintain or even improve growth performance. A few examples of strategies to optimize gut health are stricter biosecurity initiatives and nutritional strategies, such as higher use of synthetic amino acids and feed supplements like protease enzyme and organic acids. Protease supplementation helps piglets to digest protein, which minimizes many factors which are detrimental to gut health. Similarly, certain organic acids can reduce growth of pathogenic bacteria in the gut, which improves gut health and performance.
Gut health impacted by undigested protein
Despite the use of high cost and high quality feed ingredients in nursery diets, producers still encounter gut health issues in the herd. The digestive system of piglets is immature at this stage, and the transition from highly digestible milk protein to other protein sources increases the flow of undigested protein reaching the hindgut, which serves as a substrate for the overgrowth of pathogenic bacteria. In addition, immediately after weaning, the endogenous secretion of protease is decreased in nursery piglets (Figure 1). Consequently, the supply of digestible amino acids for growth is reduced, thereby reducing growth performance. Improving protein digestibility is critical to minimize the amount of undigested protein in the gut, which maximizes gut health and allows piglets to reach their full growth potential.
Protease supplementation helps gut health
Dietary protease supplementation compensates for low endogenous protease secretion and reduces the amount of undigested protein reaching the hindgut. Without it, the excess undigested protein in the hindgut is fermented by microorganisms, generating ammonia. Excessive ammonia in the hindgut is detrimental to the development of intestinal lining cells, hurting gut health and digestion and leading to impaired gut health as seen sub-clinically as sub-optimal feed conversion. Moreover, excessive ammonia leads to a higher pH in the hindgut, which increases the incidence of diarrhea, promotes the growth of pathogenic microorganisms such as E. coli, and increases mortality. An experiment with 190 nursery piglets fed diets without or with protease supplementation showed that protease supplementation decreased (P < 0.05) ammonia nitrogen concentration in the digesta at various locations along the intestinal tract of nursery piglets (Figure 2). This indicates that there was less undigested protein in the gut, less damage to the gut lining cells, and less pathogenic bacteria growth. Consequently, piglets fed diets containing protease had better (P < 0.01) fecal scores compared with piglets fed diets without protease (Figure 3), which indicates less digestive disorders like diarrhea. Feeding protease minimized (P < 0.01) inflammation as observed by the reduction of serum interleukins – 1 and – 6 (Figure 4). Intestinal inflammation is caused by the fermentation of undigested protein in the gut which damages the intestinal lining cells. Piglets fed protease also had higher ileum villi height to crypt depth ratio which indicates increased villi height and reduced crypt depth (Figure 5). This indicates greater intestinal surface area for nutrient absorption.
Another experiment with 990 nursery pigs looking at the effect on performance revealed that piglets fed protease had a 7.7% increase (P < 0.01) on average daily gain and 2.3% increase (P = 0.05) on gain to feed ratio when compared to pigs fed non-supplemented diets.
Feeding protease showed beneficial effects on gut health at sub-clinical levels by improving piglet performance and helping them to thrive. Dietary protease supplementation minimized diarrhea as demonstrated by the improvement in fecal score, minimized gut inflammation, and better preserved gut lining cell integrity. Consequently, piglets that were fed protease were one kg heavier when exiting the nursery.
Intestinal microflora influences gut health and piglet growth
A well-balanced gastrointestinal microflora contributes to piglet health and growth performance. Pathogenic microorganisms damage the lining of the cells in the gut and impair absorption of nutrients, thus reducing performance. When the cell lining is damaged, the young piglet has diminished nutrient absorption and becomes more susceptible to pathogens that may cause disease and increased mortality. Improving gut health can make piglets stronger and healthier, with increased absorption of nutrients and increased growth rates allowing for a successful lifetime growth.
Blend of organic acids delivers on gut health
Organic acid feed supplements rapidly alter the intracellular pH of intestinal bacteria, overloading its capability to stabilize the intracellular pH and, leading to the death of the bacteria. This creates an environment in the gut that minimizes the proliferation of pathogenic bacteria. An experiment was conducted with 96 nursery piglets to evaluate the effect of dietary organic acids on growth performance and microbial population of weaned piglets. The experimental diet contained a blend of organic acids. Its effect on bacterial proliferation was compared with that of dietary antibiotic supplementation (200 ppm chlortetracycline and 60 ppm Lincospectin) and a control diet with neither antibiotic nor organic acid blend. Piglets fed diets containing the organic acid blend had higher (P < 0.05) average daily gain (Figure 6) and better (P < 0.05) feed to gain ratio (Figure 7) compared with piglets fed control diets. The performance of piglets fed diets with the organic acid blend was similar to those piglets fed diets containing antibiotic (Figures 6 and 7).
At the start of the experiment, piglets from all dietary treatments had similar microbial counts, however, on day 14 piglets fed diets containing either antibiotic or the organic acid blend had higher (P < 0.05) counts of Lactobacilli in the feces (Figure 8), which are the beneficial bacteria. In addition, piglets fed the organic acid blend or antibiotics had a tendency (P = 0.08) to have lower E.coli counts in the feces (Figure 9).
In summary, several challenges related to poor gut health can be addressed with the supplementation of dietary protease and blend of organic acids. Feeding protease showed gut health benefits and helped piglets to thrive. Protease supplementation reduced undigested protein in the gut, optimized fecal score, minimized gut inflammation, and helped to preserve gut lining cell integrity. Consequently, piglets fed protease were 1 kg heavier at nursery exit. Feeding the organic acids blend also optimized the intestinal microflora by minimizing the amount of pathogenic bacteria and maximized the amount of beneficial bacteria, resulting in piglets growing more, and more efficiently. Therefore, protease (CIBENZA® DP100 enzyme feed additive, Novus International, Inc.) and an organic acids blend (ACTIVATE® DA nutritional feed acid, Novus International, Inc.) may play a key role in maximizing gut health. These can serve as nutritional tools to help piglets get stronger and healthier, especially in scenarios where antibiotic growth promoters are being curbed.
