Algae extracts to tackle diarrheal viral diseases in pig production
Nowadays, natural solutions supporting the battle against viral diseases are deeply looked at in the frame of the global reduction of medical products. Ensuring digestive welfare and reducing the digestive trouble efficiently is a way to reduce the spread of some diarrheal viral disease. Algae and clays are potent candidates to reach this goal.
Algae, a source of biological treasures
Macroalgae, or seaweeds, are eukaryotic and pluricellular organisms, divided in three different groups: green, red and brown. They contain a variable part of carbohydrates (mainly polysaccharides), proteins, minerals, lipids and vitamins. Nutritional studies on marine algae indicate that green, brown and red seaweeds possess good nutritional characteristics and could be used as an alternative source of dietary fiber, protein, vitamins and minerals (Chojnacka et al., 2012; Raposo et al., 2013). In addition, detailed screening of macroalgae functions revealed new ranges of biological activities including anticoagulant, antiviral and antibacterial, anti-tumoral, anti-proliferative and immuno-modulatory activities. All of them could be of relevance in nutraceutical functional food (Wijesekara et al., 2011a). Indeed, green, brown and red macroalgae cell wall contains large amounts of sulfated polysaccharides, named respectively ulvans, fucoidans and carrageenans, ranging from 4 up to 76% of seaweed dry weight (Holdt et al., 2011). The high content of these sulfated polysaccharides, their unusual structure, and their biological properties shed a new light on these compounds as promising natural products for medicinal and dietary applications (Rioux et al., 2007; Laurienzo et al., 2010). The specificity of algal Sulfated Polysaccharides from marine origin stands in the complexity of their structure. Indeed, they are branched polysaccharides, in contrast with linear polysaccharides like cellulose which contain only one type of linkage between sugars. Also, these specific sulfated polysaccharides are composed of various and some rare sugar units (xylose, rhamnose), unlike homo-polysaccharides like starch which are exclusively composed of glucose units. Finally, these sugars can be sulfated, conferring them a special reactivity. The whole of these parameters show a phylogenic similarity with polysaccharides from the animal kingdom such as heparin, known for its numerous biological properties, thus explaining their unique activities. Sulfated polysaccharides reactivity, hence their biological properties, varies a lot according to the type of sugars and linkage they contain, their level of sulfation and also their molecular weight. Therefore, several marine sulfated polysaccharides with distinct biological activities can be found in algae. Their specific extraction is a key to ensure a targeted effect on animals.
Olmix has been studying marine biotechnologies for more than 20 years and has focused in the past 10 years in the extraction and use of specific sulfated polysaccharides from macroalgae (MSP) to the service of animal production challenges. More particularly, Olmix has worked on the capacity of some MSP to improve digestive welfare by protecting the intestinal epithelium through the stimulation of the production of mucin in the gut.
Algae extracts for improved digestive welfare
Intestinal mucins are large glycoproteins secreted by goblet cells in the intestine. They constitute the mucus gel that coats the intestinal epithelium (Specian and Oliver, 1991) and protects it. The mucus layer prevents the attachment and colonization of bacteria on the mucosa, and limits the intestinal absorption of toxins. Therefore, stimulating the production of mucin in order to protect the intestine turns out to be a relevant strategy to support intestinal development of young piglets and to prevent digestive disorders. In 2000, Barcelo et al. demonstrated that MSP from Ulva sp stimulated the excretion of mucin from goblet cells, highlighting its potential protective use against various intestinal diseases.
From this, Olmix has developed a range of products to support digestive welfare of piglets, relying on its MSPMUCIN, which stimulates the production of mucin by goblet cells and so reinforces the intestinal mucus layer (Figure 4).
SEAGUT Paste and SEAGUT Powder are complementary feeds containing MSPMUCIN, that are respectively given in paste form directly in mouth at birth, or spread on floor in dry powder form till weaning.
Both also contain micronized montmorillonite, processed by Olmix to respect the layered structure while improving the surface of contact with environment thus improving its water and toxins adsorbtion capacity. This extra fine powder with behave as a gel in the intestine, coating it and protecting it from toxins and pathogens.
Micronized montmorillonite and MSPMUCIN work in synergy to support the intestinal development of newborn and suckling piglets, so that they have less digestive troubles in farrowing unit, and better performance around weaning.
Given this, Olmix set out to determine the impact that MSPMUCIN would have on nursing piglet performance and mortality in a barn that tested positive for Porcine Epidemic Diarrhea Virus (PEDV). This virus is one of the most detrimental diseases in the farrowing unit, causing nearly 95% mortality in nursing piglets (Stevenson et al., 2013). There is no cure for PEDv and the virus is highly recombinant, making vaccine development difficult. As such, the main strategy for dealing with a PEDV is to inoculate the sows and treat the symptoms, and minimize the inevitable losses as much as possible.
The devastating effect that PEDV has on nursing piglets stems from the fact that the virus causes wide spread enterocyte lysis resulting in severe villi atrophy and crypt lengthening (Song and Park, 2012). This causes decreased nutrient absorption, watery diarrhea, dehydration, depression, and vomiting. In an older pig, the impact of the virus is less severe, compared to nursing pigs (Stevenson et al., 2013; Schweer et al., 2016). Thus, the biggest challenge when managing a PEDv infection is in farrowing house.
By the understanding the effect the virus has on the enterocytes, and the knowledge that algae sulfated polysaccharides have the potential to improve mucosal barrier function, Olmix wanted to determine whether SEAGUT Powder would be helpful in mitigating some of the losses resulting from a PEDV break. A trial was conducted in a barn diagnosed with PEDV on 22 litters of pigs. SEAGUT Powder was administered to 11 litters, and the remaining 11 litters were given no SEAGUT Powder to serve as a control. Piglets were weaned at 21 days of age. Compared to the control litters, piglets provided SEAGUT Powder were faster growing (0.19 kg/d vs 0.15 kg/d, respectively) and heavier at weaning (5.5 kg vs 4.7 kg, respectively) (figure5) Furthermore, SEAGUT Powder decreased piglet mortality by 47% compared to the control litters. During the 6 months following the trial, the continuous use of SEAGUT Powder helped to minimize mortality rate until PEDv outbreak was completely controlled.
The combination of MSPMUCIN and clay in SEAGUT Powder allowed producers to improve piglet health and performance, in both a PEDV challenge (and a non-challenge setting – not displayed here)
Thus, combining the MSPMUCIN with clay in SEAGUT Powder is a cost effective way for producers to maintain healthier nursing piglets in the farrowing unit.
By improving piglet gut health via improved mucosal barrier function, algae sulfated polysaccharides derived from macroalgae combined with micronized clay are a viable option for producers to maintain high levels of production with their pigs while decreasing the usage of antibiotics.
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Article made possible through the contribution of Olmix Technical Service