The effect of fat-coated organic acid salts and a feed enzyme on growth performance, nutrient utilization, microflora activity, and morphology of the small intestine in broiler chickens

The efficacy of two fat-coated organic acid preparations added alone or in combination with a commercial feed enzyme to a wheat- and soyabean meal-based broiler diet was investigated. Fat-coated sodium butyrate (SB) and blend G composed of fumaric acid, calcium formate, calcium propionate and potassium sorbite were used. Each preparation was added at 1 g/kg diets cold pelleted. Two hundred 40-day-old Cobb broiler females were allocated to 6 groups, 40 in each, and fed experimental diets from the first day of life to slaughter. Histomorphometry of the jejunum and ileum was performed on eight 8-d-old chicks per group, performance was measured from day 8 to 21 of life on 16 chickens kept in individual cages per group, while the balance trial was conducted using 9 chickens per group. Measurements of digesta pH in the crop, stomach, jejunum and caecum were taken in 30-day-old birds. Additionally, viscosity of ileal digesta and short-chain fatty acid (SCFA) concentrations in caecal digesta were determined. No effect of the feed additives on small intestinal morphology was found in the ileum, but in the jejunum blend G increased the villi height (P<0.001), crypt depth (P<0.01) and the width of the tunica muscularis (P<0.05). The added enzyme decreased villi width (P<0.05). The effect of SB on intestinal morphology was insignificant. The growth performance of birds fed diets supplemented with both SB and feed enzyme was increased in comparison with other experimental groups (P<0.05). Both preparations G and SB increased nitrogen retention, while enzyme supplementation increased organic matter digestibility and the AME_N value of diets. Neither preparations G nor SB affected ileal digesta viscosity, but this parameter decreased by 10% (P<0.05) following enzyme supplementation. The effect of additives on the pH of digesta was not significant, except enzyme supplementation, which decreased the pH (P<0.05) of jejunal digesta. Neither additive affected total short-chain fatty acids concentration in caecal digesta.