Effect of microalgae Spirulina and Bacillus subtilis on carcass characteristics, intestinal morphology and blood parameters of broiler chickens

This experiment was performed to compare the effect of adding microalgae Spirulina and probiotic Bacillus subtilis in the diet on carcass characteristics, intestinal morphology and blood parameters of broiler chicks. A total of 300 Ross one-day-old Ross 308 male broiler chicken were randomly distributed in a completely randomized design with 3 × 3 factorial arrangement including three levels of Spirulina platensis (0, 0.05 and 0.1% of diet) and two levels of probiotic (0 and 0.05% of the diet) and reared for 24 days. The mixture of 0.1% spirulina and probiotic decreased the relative weight of abdominal fat pad when compared to the treatment provided with 0.1% spirulina and without probiotic. The use of probiotic diet (without spirulina) increased the duodenal villus height and the ratio of villus height to crypt depth compared to the treatment without these additives (P <0.05). In the jejunum, the mixture of 0.05% Spirulina and probiotics increased the villus height than the treatment containing only probiotic (P <0.05). Supplementing of spirulina or probiotic can reduce heterophil count and the heterophile to lymphocyte ratio in the boold of broiler chickens (P< 0.05). The results of this experiment showed that spirulina, especially 0.1% level, alone or in combination with probiotic, can improve carcass quality and intestinal mophology. Also, due to the beneficial changes in blood parameters, each of these additives could be recomendable to improve the health of broiler chickens.