Challenges of piglets with removal of AGP’s and medical zinc from the diet

Juhani Vuorenmaa, R&D Director

Young piglets are highly susceptible to a variety of diseases due to the immaturity of their active immunity and pathogen challenge from the environment. Removal of antibiotic growth promoters and medical zinc from the diets is increasing the risk for these problems.

Diets and ingredients, which can enhance the development of the active immunity of piglets  and help against pathogen pressure, are thus valuable. At the same time, piglets are also undergoing a transition from sow’s milk to solid feed which challenges their undeveloped digestion tract. The development of piglet’s digestion system can be enhanced by dietary means and help them to adapt quicker to the solid feed.

Hankkija has produced antibiotic free piglet feeds since 1999 and the production of feeds containing medical zinc has been infrequent. We have tried to learn dietary means to support the gut development and health of piglets over the years. The optimized composition of our feeds is supplemented by the patented yeast hydrolysate Progut® which has shown to modulate the immunity and microbiota of the piglets thus improving their performance and wellbeing.

Dietary changes for reducing weaning problems of piglets in antibiotic free feeding

The use of in-feed antibiotics and medical zinc for controlling the weaning problems have allowed nutritionist to focus on maximizing piglet growth with high protein and energy density weaner feeds. Change of this traditional way of formulation is needed in successful antibiotic free feeding. The ability of young piglet to digest protein is very limited. Undigested protein passing through the small intestine is increasing the growth of pathogenic bacteria and causing harmful protein fermentation with increased diarrhea risk. For this reason, the protein levels of Hankkija’s weaner feeds were reduced from 20-22 % to 16-17 % when the use of antibiotics was stopped 20 years ago. Addition of organic acids is supporting this by reducing the pH in the stomach to more optimal level for protein digestion. The use of NSP enzymes is a good way to help the piglets to digest their feed better. Piglet’s ability to digest fat is also limited and high fat additions in the weaner diets should be avoided.

The target of maximal digestibility has lead into very fine particle size of the weaner feeds which is not good for development of the digestive tract. According to our trials and practical experience increase of the feed particle size, especially by the use of rolled cereals, is beneficial for the gut health. There is also scientific research showing that addition of insoluble fiber in the weaner feed is beneficial for the gut health helping the piglets to cope better with the challenges of weaning. Part of the weaning problems are arising from poor feed intake. A big proportion of piglets are eating very little feed during the first days after weaning which has detrimental effects on the condition of their intestine. Allowance to creep feed and maximizing its intake help the piglets to adapt to solid feed and improve the feed intake after weaning.

Progut® trains the immunity of piglets helping them to cope better with the weaning challenges

The yeast hydrolysate product Progut® contains several immune stimulating compounds (β-glucan, mannoprotein and chitin structures) and has increased water-solubility for better visibility to immune receptors. It has shown to increase the production of IP-10 cytokine which is a known chemo-attractant involved in the recruitment of T-lymphocytes. Most likely for this reason, it has shown to increase the amount of T-lymphocytes and immunoglobulin production in the gut in different animal species. Due to these functions it has enhanced the immune responses of young animals under challenge. In a way, Progut® trains the immune system of young animals to cope better with the challenges.

The effect of Progut® on the immune responses and performance of weaned piglets was investigated in a trial that was conducted at Schothorst Feed Research (Initiates file downloadMolist et al. 2014). 120 piglets were were distributed into a negative control diet and the same diet supplemented with 0.2 % of Progut®.  At days 7 and 21 of the experiment, half of the piglets per group were challenged intramuscularly with sheep red blood cells (SRBC). Progut® inclusion in the weaner diet improved feed conversion ratio (P=0.025) for the whole trial period of 28 days, tended to increase IgG (P=0.087) and IgM (P=0.061) antibodies in the serum and increased (P=0.037) SRBC agglutination titers. The results from this study suggest that Progut® supplementation to weanling piglets triggered the immune system to a more responsive state without penalizing the animal performance which could be beneficial for overcoming disease challenges.

Progut® prevents pathogenic E. coli attachment to gut mucus and reduces diarrhea frequency

One of the most common reasons for diarrhea in weaned piglets is pathogenic E. coli bacteria. The adherence of E. coli to gut mucus can be reduced by yeast products if they contain right types of molecular structures. These three-dimensional structures are specific enough for the working interactions with the bacterial fimbria. Numerous in vitro attachment and binding studies have shown that the content of the soluble bioactive yeast structures correlates well with the E. coli binding capacity. Progut® is produced by a specific hydrolysis process and is rich in the bioactive molecular structures. Thus, it has high amount of binding sites for E. coli and an outstanding efficacy to reduce its adherence.

The in vivo effect of Progut® on pathogenic E. coli and diarrhea frequency of weaned piglets was studied in a challenge trial that was carried out at Aarhus University Denmark (Initiates file downloadJensen et al. 2013). Piglets from E. coli susceptible sows were weaned at 4 weeks of age and allocated to trial treatments. In one of the treatments, Progut® was added into piglet feed during suckling period and after weaning which was compared to the control group receiving same feeds without Progut® addition. Two * 10 piglets per treatment were individually housed after weaning. Half of them were challenged on days 1, 2 and 3 after weaning with 2*108 CFU E. coli O149 and the other half received a placebo treatment of sodium bicarbonate. Addition of Progut® in the feed reduced (P=0.026) the fecal shedding of haemolytic E. coli in the challenged piglets (figure 1) and it also reduced their average diarrhea scores (figure 2).

Successful weaning of piglets without antibiotics and medical zinc can be supported by modification of diet composition and structure. The yeast hydrolysate product Progut® can speed up the immune maturation of piglets and help them to overcome disease challenges. It has also shown to reduce pathogenic E. coli growth and diarrhea frequency thus improving the performance and wellbeing of piglets under the challenging conditions around weaning.