A summary of feed additives, intestinal health and intestinal alkaline phosphatase in piglet nutrition

Abstract

Weaning is considered the “critical window” in the piglet’s life because it is associated with several stress factors, such as loss of contact with the mother and original litter, solid diet, environmental and structural changes, and the establishment of a new hierarchy. During this abrupt period, several events such as reduced feed intake, high morbidity, susceptibility to enteric infections and post-weaning diarrhoea are observed. The nutritional landscape of the piglet gut is modified, which can compromise the maturity of the gastrointestinal system, the stable intestinal microbiome and the active immunity developed as an indicator of intestinal health. However, with increased awareness of feed safety issues and the development of drug-resistant bacteria, the interest in producing pigs without the use of antimicrobial growth promoters (AGP) is increasing, since long-term use and therapeutic doses of AGP can contribute to the reduction of bacterial diversity and increase of inflammatory bowel disease (IBD). Thus, the most widely researched alternatives include the use of feed additives, feeding strategies, nutraceuticals/functional foods and available handling that can reduce the risk of IBD beyond basic nutritional functions. Studies have reported intestinal alkaline phosphatase as a new nutritional therapy associated with intestinal health which may be a “key additive” in the AGP replacement. In this review article, the purpose is to show some current aspects of feed additive research, addressing a concept of the “intestinal health” from different points of view and properties of alkaline phosphatase.

Extraction, purification, and in vitro biological activities of intestinal alkaline phosphatase from pig intestine mucous waste

“…Compared with the intestine of the calf and the ordinary pig, the intestine of the organic pig was thicker, and the proportion of mucous membrane was higher, so the content of IAP was higher. Compared with the ordinary pig, the organic pig was free‐range and they were fed with corn, chaff, weeds, sweet potatoes, and a small amount of concentrate feed, this directly affected IAP activity in their intestinal mucosa (Genova et al, 2020; Melo et al, 2016). Additionally, due to the presence of Gram‐negative bacteria in the intestinal mucosa, the most serious extraction problem was sterilization and fear of loss of IAP activity.…”

Oral administration of nucleotides in calves: Effects on oxidative status, immune response, and intestinal mucosa development

“…Similarly in both groups, serum ALP activity varied widely within the physiological range (166-5,118 U/L; Onomi et al, 2019). Distribution of ALP is wide across different tissues (e.g., liver, bone, intestinal mucosa, kidney, and leukocytes), with a plurality of isoenzymes showing dis-tinct physicochemical properties (Genova et al, 2020). Overall, the increase of ALP activity in newborn calves may be related to colostrum intake or to the production of endogenous enzymes in response to the rapid skeletal growth or to the activity of some organs (De Palo et al, 2018;Onomi et al, 2019).…”

Oral supplementation of alkaline phosphatase in poultry and swine

“…Isoforms of mammalian AP are classified into two groups the tissue nonspecific alkaline phosphatases (TNAP), predominantly expressed in liver, kidney, and bones and the other are tissue-specific AP, germ cell alkaline phosphatase (GCALP), placental alkaline phosphatase (PLAP) expressed in thymus and testis, and IAP ( Estaki et al, 2014 ). IAP, is a brush border enzyme, expressed and secreted by enterocytes, it is active within the mucosal membrane and is secreted into the intestinal lumen, serum, and in stool ( Genova et al, 2020 ).…”

“…IAP is an integral part of gut mucosal defense ( Goldberg et al, 2008 ). IAP is known to dephosphorylate bacterial lipopolysaccharide (LPS) which is predominantly produced by Gram-negative bacteria, leading to reduction of inflammation in the gut ( Lee et al, 2014 ; Genova et al, 2020 ), regulate protective surface microclimate by dephosphorylation of luminal ATP and modulating intestinal pH ( Akiba et al, 2007 ; Mizumori et al, 2009 ), maintain inorganic phosphate homeostasis ( Sasaki et al, 2018 ), dephosphorylate uridine diphosphate which is involved in inflammatory cascade ( Moss et al, 2013 ), and reduce bacterial translocation ( Wang et al, 2015 ). Overall, IAP plays an integral role in maintaining intestinal homeostasis.…”

“…Overall, IAP plays an integral role in maintaining intestinal homeostasis. Several studies in animals have established that oral supplementation of IAP in feed can assist in the amelioration of intestinal and systemic inflammation in a variety of diseases including dysbiosis and inflammatory bowel disease ( Genova et al, 2020 ). Gut-associated diseases are easily transmitted and have a high morbidity rate, leading to poor feed conversion ratios causing large economic losses in production animals.…”