Effect of fungal gamma-linolenic acid and beta-carotene containing prefermented feed on immunity and gut of broiler chicken

Gamma-linolenic acid (GLA) is a fatty acid from the ω-6 family. It is able to deliver a wide range of health benefits arising from its anti-inflammatory effects. An insufficient supply of GLA from agricultural and animal sources resulted in the development of a fermentation technique using lower filamentous fungi, which have the ability to accumulate high concentrations of GLA and beta-carotene during solid-state fermentation of cereals. The goal of this study was to observe the influence of the addition of prefermented cereal product, containing high amounts of GLA and beta-carotene, into the feed of broiler chickens on their immune status, and also the number of lactic acid bacteria and enterobacteria in gut content, which has never been studied before. Immunostimulation in the GLA group was manifested by a significant increase in the oxidative burst of phagocytes, CD4+CD8- lymphocytes in blood, and the CD4: CD8 ratio. Upregulation of gene expression for IgA in the GLA group indicates that the B-lymphocytes were stimulated at a local gut level. In the caecum, increased mRNA expression for mucin-2 and insulin-like growth factor was observed in the GLA group, which could contribute mainly to the protection of the intestinal mucosa and to better growth and regeneration of skeletal muscles. Improved immune activation and protection of the intestinal mucosa were subsequently reflected in a change of the microbial composition in gut contents; a significant reduction of enterobacteria occurred after GLA administration. We can conclude that prefermented cereals containing fungal GLA and beta-carotene represent a low-cost supplement for broiler diet having a beneficial health effect.