The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella typhimurium

Abstract

An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one-day-old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10(9) cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10(9) cfu/g). All birds were orally challenged with 2 ml suspension, containing 10(4) cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p < 0.05). Intestinal and excreta Salmonella number, and excreta ammonia gas emission in the PC treatment or Bacillus treatments, was lower than the NC treatment (p < 0.05). Breast pH, colour and water-holding capacity were not affected by supplementation of B. subtilis RX7 and B2A. However, drip loss at 1 day post-slaughter from birds fed with B. subtilis RX7 and B2A decreased, compared with the positive control birds (p < 0.05). Relative gizzard weights of birds fed B. subtilis RX7 and B2A were significantly higher than the NC birds under S. typhimurium challenge. It is concluded from the results that B. subtilis RX7 and B2A increased the gizzard weight and decreased the intestinal and excreta Salmonella population and excreta ammonia gas, and drip loss of breast meat after being stored for 1 day, under stress caused by the S. typhimurium challenge.

Dietary Bacillus subtilis B2A strain in laying hens challenged with Salmonella gallinarum: effects on egg production, egg quality, blood haptoglobin and targeted intestinal Salmonella shedding

“…Numerous studies have shown that birds consuming diets supplemented with B. subtilis, which is known to increase the intestinal lactic acid, have a lower incidence of Salmonella than those fed control diets (Wu et al 2009;Knap et al 2011). A recent study reported by Park and Kim (2014) showed that when 21-day-old chicks were dosed with B. subtilis B2A or B. subtilis RX7 and later challenged with S. ,SalmonellaB. subtilis showed significant differences in Salmonella population in the intestine, it has been suggested that this might be the metabolic effects of obligate spore-forming aerobes on pathogens.…”

“…It is widely accepted that commensal or probiotic organisms prevent colonization of pathogens in the gut epithelial surface by competitive exclusion. Most of the research aimed at finding a novel B. subtilis strain which can inhibit the infectious activity of S. gallinarum in order to decrease the prevalence of Salmonella in experimentally challenged laying hens that are not necessarily showing symptoms of a disease (Knap et al 2011;Park & Kim 2014). In the current experiment, we observed a distinct effect due to the concentration of probiotic treatments administered.…”

“…There is extensive literature describing the competitive effects of B. subtilis spores in poultry; most of the studies report an increase in modulation of intestinal microbiota in favour of lactic acid bacteria (Wu et al 2009;Park & Kim 2014). The ability of B. subtilis spores to protect against the Salmonella Heidelberg challenge with 58% reduction in Salmonella-positive drag swabs compared with control chickens may be due to the acidification of the intestinal environment which inhibits the growth of detrimental bacteria in chickens (Knap et al 2011).…”

“…They reported that only 38% of laying hens from the B. subtilis-treated group were Salmonella-positive, whereas 62% of laying hens were still Salmonella-negative in the untreated control treatment; however, no significant differences were detected in performance variables in Leghorn chickens. Park and Kim (2014) also reviewed the activity of B. subtilis spores and indicated that they inhibit Salmonella proliferation in the large and small intestine, decrease ammonia emission from excreta and decrease haptoglobin level in plasma.…”

“…This has provided impetus to the application of biological substances such as probiotics, which have been reported to be beneficial for food animal production. Several investigators have examined the positive effect of probiotics on Salmonella proliferation in poultry (Knap et al 2011;Park & Kim 2014;Upadhaya et al 2016) and pig Zhao & Kim 2015). Bacillus subtilis is a spore-forming anaerobic bacterium (Wu et al 2009), which can be used as a single bacterial strain or a mixture of different species to prevent the colonization of pathogens in the gastrointestinal tract of poultry and to improve some aspects of their health.…”