LAUSR

High amounts of grains in equine diet lead to an excessive starch intake modifying microbial populations and fermentative products. These changes could compromise the gastrointestinal barrier which has serious consequences for equine health. Therefore, feed additives are receiving great attention to minimize negative effects related to high starch level inclusion. Macleaya cordata compounds are being used in animal nutrition for their multiple biological effects, including anti-inflammatory and antibiotic properties. However there is no information about effects on horses. The aim of this study was to evaluate effects of increasing levels of a Macleaya cordata commercial phytotherapic on gastrointestinal tract and systemic inflammation of ponies fed a high starch diet. Eight gelding ponies, Mini-Horse breed, healthy, mean age 8.59+0.17 years old and mean body weight (BW) 146.72+16.53 kg were used. Experimental design was contemporary double Latin-square 4 × 4. Experimental unit was the animal inside each experimental period (n = 8 units per treatment). Each experimental period lasted 20 d. Diet attended daily maintenance nutritional requirement of 1.75% BW in dry matter in a concentrate:roughage proportion of 60:40. Daily starch amount was 4.4 g/kg BW, divided in 2 meals. Water and mineral salt were provided ad libitum. Animals were separated in 4 groups: 1) Control: concentrate without food additive, 2) S1: concentrate with 1 mg of phytotherapic/kg BW, 3) S1.5: concentrate with 1.5 mg of phytotherapic/kg BW, 4) S2: concentrate with 2 mg of phytotherapic/kg BW. Right dorsal colon wall thickness was measured by ultrasonography to determine local inflammation at 9:30 a.m. on d 20. Esaote MyLabTMDelta and a micro convex probe were used. Best image was selected using MyLabTM Desk3 software and 3 measures were taken for mean. For systemic inflammation, blood samples were collected at 9 a.m. on d 19. Fibrinogen was dosed by heat precipitation method and interleukins 6 and 10 gene expression in peripheral blood mononuclear cells (PBMC) was obtained using qPCR. Data were analyzed by Statistical Analysis System program with PROC MIXED. Significant level was 5%. Intestinal wall was thinner (P = 0.0071) in all treated groups (Control: 3.08 mm; S1: 2.59 mm; S1.5: 2.53 mm; S2: 2.44 mm). There were no statistical differences between groups for systemic inflammatory parameters. In conclusion, Macleaya cordata commercial phytotherapic addition in high starch equine diet modulates local immunity, but has no impact on systemic inflammation.