Mycotoxins are toxic secondary fungal metabolites found worldwide in various foods and animal feeds. Deoxynivalenol (DON), also known as vomitoxin, is a kind of mycotoxin mainly produced by Fusarium. graminearum, which easily occurs in grains, such as barley, maize and wheat. Contamination with DON will pose a food safety risk in human and animal food chains which induces acute emetic effects after consumption. Pigs are the most sensitive species responding to DON. So it is the best model for DON infection on human and animal intestine or immune system.

Effect of DON contaminated feeds in pigs were examined in previous studies. With the feeding of Fusarium toxin contaminated grains, body weight and feed intake of pigs were decreased. The immune system and internal organs were also partially damaged. However, the risk of this contamination was not well solved in animal feeding husbandry. Until now, several strategies were used for resistance of DON in contaminated grains, such as chemical detoxification, biological detoxification and commercial adsorbent. But these approaches have many problems in implementation, such as non-selectivity for substrate, negative effect on grain quality, etc.

Arginine-family amino acids play important regulatory functions in swine nutrition, especially in nutrient metabolism and immune response. Arginine and glutamine are the prototypes with pivotal functions among Arginine-family amino acids. It has been reported that dietary supplementation of these two amino acids would improve porcine intestinal immunity and growth performance. Even though many studies focused on the function of amino acids in pig nutrient metabolism, few studies have examined the roles of arginine and glutamine in DON infected growing pigs. The objective of the research was to investigate the effects of dietary amino acid supplementation on alleviating the impairment and enhance immunity induced by DON stress in growing pigs.

In the experiment, a total of forty healthy growing pigs (Landrace×Yorkshire) with a mean body weight (16.28±1.54Kg) were divided into 5 groups randomly. Before experiment, 3 amino acid groups fed 1.0% arginine (Arg), 1.0% glutamine (Gln) and 0.5%Arg+0.5%Gln respectively for 7 days for immune-fortification. Control group and toxic group fed diet with 1.64% Ala for isonitrogenous control. After immune-fortification, the toxic group and amino acid groups fed DON-contaminated diet with the final DON concentration 6mg/kg in diet. Amino acid groups continually fed with amino acids supplementation as before. The control group fed with DON-free commercial diet at the same time. Voluntary feed intake for 21 days and consequently, no big difference between DON group and amino acid groups was observed for the average daily gain (ADG) of pig, the average daily feed intake (ADFI) of amino acid groups were significantly higher than that in toxic group (P< 0.01).  As to the ratio of feed to gain (F/G), DON group is the lowest which is affected by the feed refusal during feeding period (P< 0.05). The relative live weight gain in DON group was 10.66% heavier compared with that of control and glutamine groups respectively. As to spleen and kidney, there is no significant difference among these groups.  For serum biochemistry characters, values of BUN, ALP, ALT and AST in amino acid groups were lower than that in toxic group. GLU and ALB were no significant difference between control and amino acid groups. As to the serum hormonal characters and cytokines, IGF1, GH and SOD in amino acid groups were significantly higher than that in toxic group (P<0.01). IL-2 and TNFαvalues in amino acid groups were similar with that in control group, which were significantly lower than that in toxic group (P<0.01). Amino acid supplementation increased the expression of CAT1 and EAAC1 in porcine intestine.

In conclusion, dietary amino acid supplementation could alleviate the anorexic effects significantly for DON-contaminated pigs; at the same time, increasing amino acids utilization in pigs alleviated the impairment induced by DON stress in growing pigs.

Details of this research could be found at http://dx.plos.org/10.1371/journal.pone.0069502