Effect of an organic acid blend and phytase added to a rapeseed cake-containing diet on performance, intestinal morphology, caecal microflora activity and thyroid status of broiler chickens

Abstract

The experiment was carried out on 96 female broilers, allocated to eight groups of 12 birds kept in individual cages. Two basal wheat- and soyabean meal-based diets containing 150 g/kg of rapeseed expeller cake were formulated, differing in the level of P: 7.1 g/kg in diet H or 5.9 g/kg in diet L. Rapeseed cake supplied 3.15 micromol alkenyl glucosinolates per gram of diet. The eight treatments were: basal diets only, basal diets + phytase (1000 U/kg), basal diets + organic acid blend (OA, 6 g/kg), or basal diets + both additives. Diets were fed from day 8 to 28 of life. The results showed that the lower dietary P content and OA supplementation did not significantly affect feed intake or BWG, while both increased (p < 0.001) after phytase supplementation. Tibia ash content as well as tibia ultimate strength were lower (p < 0.001) in birds fed diets L compared with diets H, and increased (p < 0.01) with phytase supplementation of diet L, while OA had no influence on either parameter. Dietary P levels and OA supplementation had no influence on the pH of gut digesta, but the pH of jejunal digesta increased following phytase supplementation (p < 0.01). Morphological measurements of the small intestinal mucosa of chicks indicated that OA added to diet L depressed villi height (p < 0.001) and crypt depth (p < 0.001); both parameters increased after phytase supplementation (p < 0.01). The lower total SCFA as well as acetic, propionic and butyric acid concentrations in caecal digesta indicated lower activity of caecal microflora in birds fed diets L compared with H. OA supplementation had no influence, while phytase supplementation increased the concentration of acetic acid in caecal digesta. Supplementation of diets with either phytase or OA increased thyroid weight by 16% (p < 0.01) and 11% (p < 0.05) respectively. The increase in thyroid weight because of phytase supplementation was greater at the lower dietary P level, and the greatest when both phytase and OA were added to the diet.

The nutritive value and phosphorus availability of yellow- and dark-seeded rapeseed cakes and the effects of phytase supplementation in broilers

“…Phytase supplementation increased the SCFA concentration in caecal digesta, decreased liver weight and did not affect thyroid weight. In our former studies we also found an increase of SCFA concentration in caecal digesta after supplementation of a rapeseed cake-containing diet with phytase, but this was accompanied by an increase of thyroid weight in broilers (Smulikowska et al, 2006(Smulikowska et al, , 2010. It is worth noting that the glucosinolate levels in press cakes in the former studies were higher.…”

Phytogenic additives and organic acids in broiler chicken diets

“…Although there are no performance differences between the treatments, the association of phytogenic additves and organic acids can be used in order to improve performance. Additive and/or synergistic effect was observed with the combinations of probiotics and acidifiers (Khosravi et al, 2010), sanguinarine and organic acids (Vieira et al, 2008), essential oils and enzymes (Basmacioğlu Malayoğlu et al, 2010), acidifiers and enzymes (Smulikowska et al, 2010) and phytogenics and probiotics, improving the immune system of the birds (Li et al, 2009).…”

The role of added feed enzymes in promoting gut health in swine and poultry

“…Clostridium thrives on mucin, and a reduction in mucin levels could correspond to a reduction in C. perfringens and the occurrence of NE (74) . Increased caecal acetate was reported in broiler chickens fed phytase, an indication of microbial activity modulation (75) . In pigs, supplemental phytase was observed to increase Clostridium group in the ileum without changing total bacterial numbers (76) and Bifidobacterium and Clostridium numbers (77) in the ileum.…”