efficacy of pediococcus acidilactici- based probiotic on performance, nutrient digestibility, intestinal histology and microflora in broiler chickens

introduction in many countries, poultry industry is an important economic activity. consequences of the use of antibiotics, as a growth-promoting additive, were the appearance of bacterial resistance, thus limiting the use of antibiotics led to find safer alternatives by researchers and probiotics have been introduced as a suitable alternative. according to the definition of the fullers: probiotics are “a live microbial feed supplements, which beneficially affect the host animal by improving its intestinal microbial balance”. many bacterial species such as lactobacillus spp, streptococcus, bacillus, bifidobacterium, enterococcus, aspergillus have been used as a probiotics. lactobacilli are one of the most important probiotic groups in poultry nutrition. the most important mode of action of probiotics in preventing growth of pathogens in intestine includes: less favorable conditions for pathogens colonization and development and stimulation of positive (lactic) flora. also, lactobacilli colonize the gut wall and block the binding sites of pathogenic bacteria by the use of the mechanism of competitive exclusion and it can affect pathogenic bacteria by producing lactic acid. as a general rule on when and how the use of probiotics for poultry must be taken to appropriate conditions for establishment and reproduction of these microorganisms in the digestive tract is provided. the aim of this study was to investigate the efficacy of pediococcus acidilactici- based probiotic (pa) on performance, intestinal histomorphology, microflora and nutrient digestibility in broiler chickens from 1-42 days. materials and methods a total of 260 male ross 308 broiler chicks were divided randomly into 4 experimental treatments. each treatment had 5 replicates and each replicate was assigned to a pen with 13 birds (1*1m). birds were given ad libitum access to water and diet. the experimental treatments received a basal diet that was supplemented as follows: control group(c) chicks were fed a basal diet with no probiotic added. in group spray(s), probiotic solution was sprayed above one day- old chicks. in diet (d) group, the basal diet was supplemented with pa at 100 mg.kg-1 of feed for whole trial period and in feed and spray (s-d) group chickens were treated with both of probiotic solution was sprayed above one day- old chicks and then diet was supplemented with pa at 100 mg.kg-1 of feed for whole trial period. results and discussion feed intake was not affected by any of the treatments. chickens sprayed with pa, had a higher daily weight gain them those fed diet supplemented with pa and chicks spray on day one and fed diet supplemented with pa. however, no significant difference observed between sprayed chickens and control birds. was observed feed conversion ratio, in sprayed chickens, was significantly lower than those fed diet supplemented with pa and chickens that received pa through spray + diet. again, there was no significant difference between sprayed chickens and control ones. in sprayed chickens and those received pa through spray + diet, crude protein digestibility was not significantly different from that in control chickens. but, crude protein digestibility in chickens fed diet supplemented with pa was significantly reduced when compared to those of the control chickens and chickens sprayed with pa and chickens than those received pa through spray + diet. ash digestibility significantly reduced in chickens fed diet supplemented with pa and chickens that received pa through spray + diet, compared to control chickens. the chickens that received pa through spray + diet had longer villus height and crypt depth in jejunum as compared to others at 42 days. also, in chickens that received pa through spray + diet, villus height to crypt depth ratio increased in compared with the chickens fed diet supplemented with pa. among the chickens receiving pa with the different methods, chickens sprayed with pa and chickens that received pa through spray + diet, increase lactobacillus numbers of the ileum. conclusion this study showed beneficial effects of early use of pediococcus acidilactici- based probiotic on broiler chickens. the treated birds improved bw, fcr, crude protein digestibility and increase of lactobacillus numbers of the ileum and villus height of jejunum when compared with chickens fed diet supplemented with pa. however, the positive impact resulting from the use of this probiotic in daily gain, feed conversion and crude protein digestibility in broilers receiving probiotics compared with those who received it were not observed.