Valeric acid glyceride esters in feed promote broiler performance and reduce the incidence of necrotic enteritis

Valeric acid is a C5 fatty acid, naturally produced in low concentrations by specific members of the microbiota of the lower intestinal tract. Effects of valeric acid on intestinal health have been poorly investigated. Valeric acid derivatives can be produced as glyceride esters and added to broiler feed. In the current study, experiments were carried out to evaluate the effect of valeric acid glycerides (GVA) on growth performance, on the morphology of the small intestinal mucosa and on protection against necrotic enteritis. In a first feeding trial, Ross-308 chicks were randomly divided into 2 dietary treatment groups and fed either a non-supplemented diet or a diet supplemented with GVA (1.5 g/kg). In the GVA supplemented group, the feed conversion ratio was significantly decreased during the entire trial period (D1-37). In a second trial, gut wall morphology was evaluated. In broilers fed a GVA-containing diet at 5 g/kg, the villus height/crypt depth ratio in the jejunum was significantly increased (P ≤ 0.05), and the crypt depth was significantly decreased at 28 d. In a third trial, immunohistochemistry showed that the density of glucagon-like peptide-2 immunoreactive cells in jejunal and ileal villi from broilers supplemented with GVA (5 g/kg) was significantly increased (P ≤ 0.05) on d 10. In a necrotic enteritis challenge model, a significant reduction of the number of birds with necrotic lesions was found at d 21, using in-feed supplementation of low and high regimen of GVA. These data show that GVA supplementation to broiler feed can decrease the feed conversion, positively affect the morphology of the small intestinal mucosa, increase the density of glucagon-like peptide-2 producing enteroendocrine cells, and reduce the incidence of necrotic enteritis, making GVA a valuable candidate feed additive for broilers.