EVALUATION OF SODIUM BUTYRATE AND NUTRIENT CONCENTRATION FOR BROILER CHICKENS: Protected sodium butyrate softens nutrient reduction effect in broiler chicken diets

ABSTRACT The relation between nutrition and intestinal health is a subject with an increasing interest in research, as nutritionists need knowledge about what effects formulation may have on different parameters in the gastrointestinal tract (GIT). That is why a series of four trials were conducted to evaluate the effect of nutrient concentration and a feed additive (sodium butyrate protected with sodium salts of palm fatty acid distillates (PSB, Gustor N'RGY® produced by Norel S.A., dosed at 1 kg/t), on performance, diet digestibility, intestinal morphology, volatile fatty acid concentration (VFA) in the GIT and intestinal microbiota of broiler chickens, when fed diets with different energy and amino acids concentration. Control diets, C, with the recommended metabolizable energy (ME) and ideal amino acid (AA) composition; Reduction 1, R1, C - 60 kcal ME and – 2.3% AA and Reduction 2, R2, C – 120 kcal ME and – 4.6% AA) based on different feed ingredients (Corn Soy (CS) and Wheat Barley Soy (WBS) were formulated. All trials lasted 42 days. In two of those trials (2 and 4), the nutrient densities affected performance of the animals significantly, decreasing performance with the dilution of the nutrients in the diet. In all four trials, the addition of PSB showed an improvement in animal performance (increasing growth or improving FCR), despite the different situations. In two of the trials (1 and 4), animals receiving R1 diets and PSB showed similar performance to those receiving C diets without PSB. Gross energy metabolizability was improved in T3 by the addition of PSB (69.94 vs 72.55; P: 0.02). Nutrient concentration affected histology results in T1 (tendency in duodenum), T2 (ileum) and T3 (jejunum), and PSB showed effects in T1 (tendency in jejunum), T2 (jejunum, ileum) and in T3 (jejunum). In T1, the addition of PSB affected VFA in duodenum, jejunum and ileum, changing the profile depending on diet nutrient concentration. Microbiology was affected by the inclusion of PSB in caecum of animals in T2. It can be concluded that the dilution of ME and AA concentration of the diet impairs animal performance, influences intestinal microbiota and affects intestinal histology. The addition of PSB improves animal performance, increases gross energy metabolizability in some cases, steers intestinal microbiota and alters volatile fatty acid concentrations in the intestine. The addition of PSB may help the animal to counteract the negative effect of receiving diluted diets.