Pre- and probiotics, functional plant components, antimicrobial proteins, spray-dried animal plasma, and omega-3 fatty acids are perspective dietary interventions for improving immune competence of farm animals. This was concluded in a review of literature under the Feed4Foodure program line “Nutrition, Intestinal Health, and Immunity” which aims to contribute to a reduction in the use of antibiotics in livestock farming by increasing general health and disease resistance.
Infectious diseases greatly impair animal welfare and efficiency of nutrient use and thus enlarges the environmental footprint of animal production. Nutrition may aid in reducing the incidence of diseases by enhancing immune competence. Immune competence is defined as the ability of the immune system to respond adequately on an antigenic stimulus by an appropriate immune response with a good balance between tolerance and inflammation. The literature review published by Wageningen UR Livestock Research summarizes the effects of nutritional interventions in the maternal, neonatal and post-neonatal phase on the development of the innate and acquired immune system in mainly pigs and chicken. The report ‘Nutritional intervention in animals: benchmarking of strategies, monitoring biomarkers and immune competence’ also describes human and animal models and available tools for testing immune competence; and provides insight in how the gastro-intestinal and airway mucosal immune systems interact with each other.
Feed4Foodure is a public-private partnership between the Dutch Ministry of Economic Affairs, a consortium of various organizations within the animal production chain and Wageningen UR Livestock Research. Feed4Foodure aims to contribute to sustainable and healthy livestock farming in the Netherlands, simultaneously strengthening our competitive position on the global market. For the current study, scientist of Wageningen UR Livestock Research, Wageningen University and Utrecht University worked together with representatives from the various private partners, including Agrifirm, ForFarmers, Nutreco, De Heus, Denkavit, and Darling Ingredients International.
Interventions in the maternal stage
A general remark, which is valid for all stages, is that for a well-functioning immune system, nutritional deficiencies in terms of amino acids, minerals and vitamins should be prevented.
Trans-generational effects of maternal dietary interventions on improvement of gut health and immune competence has been demonstrated in mammals (mice, rats, pigs, humans) as well as in poultry. The reviewed dietary interventions can be categorized into fatty acids, seaweed extracts, pre- and probiotics, and vitamins and minerals. The dietary interventions showed a variety in modes of action. They could affect the composition of the microbiota, the numbers or activity of specific immune cells, the gut morphology, and the expression of genes involved in immune response. Supplementation of the maternal diets with seaweed extracts, Saccharomyces cerevisiae, zinc or β-carotene resulted in improved animal performance or reduced incidence of diarrhea of the offspring. Supplementation of maternal diets with omega-3 fatty acids showed to have a wide impact on the immune competence of the progeny. Therefore, modulating the dietary fatty acid profile of maternal diets seems to be a promising intervention for improving immune competence of the progeny.
Interventions in the neonatal phase
The most abundant investigated nutritional interventions in the neonatal phase were prebiotics, probiotics and long-chain poly unsaturated fatty acids. Based on the studies that were focused on nutritional interventions in the neonatal phase of pigs, it can be concluded that prebiotics and spray dried plasma could be potential candidates to further investigation. For chickens, evidence of nutritional effects on improved immune competence was found in supplementation of wheat/soy diets, addition of methionine and cysteine above the requirements for maximal growth, as well as in addition of a mixture of vitamin E and selenium. From the studies performed with human infants we concluded that one must avoid a depletion of vitamins and/or minerals in the diet.
Interventions in the post-neonatal phase
In the post-neonatal phase, it was shown that dietary addition of glutamine improved gut integrity and increased number of immune cells in blood. Herbs or functional components in plants, e.g. black cumin, chitosan or quercitine, showed to improve gut integrity, local or systemic immune responses, composition of gut microbiota and performance parameters. Compared to digestive starch, resistant starch showed to have significant improving effects on immunological pathways in the colon of pigs as well as on the composition of the microflora. Some probiotics also positively affected the immune competence. Antimicrobial proteins, e.g. buforin II and lysozyme, improved performance levels and gut integrity, and reduced faecal excretion of clostridia, E. coli, and coliforms.