Search

As a foodborne pathogen of global importance, Salmonella entericaserovar Enteritidis (S.Enteritidis) is a threat to public health that is mainly spread by poultry products. Intestinal Enterobacteriaceae can inhibit the colonization of S.Enteritidis and are regarded as a potential antibiotic substitute. We investigated, in chicks, the anti-S.Enteritidis effects of Escherichia coli(E. coli) Nissle 1917, the most well-known probiotic member of Enterobacteriaceae. Eighty 1-d-old healthy female AA broilers were randomly divided into 4 groups, with 20 in each group, namely the negative control (group P), the E. coliNissle 1917-treated group (group N), the S. Enteritidis-infected group (group S) and the E. coliNissle 1917-treated and S. Enteritidis-infected group (group NS). From d 5 to 7, chicks in groups N and NS were orally gavaged once a day with E. coliNissle 1917 and in groups P and S were administered the same volume of sterile PBS. At d 8, the chicks in groups S and NS were orally gavaged with S. Enteritidis and in groups P and N were administered the same volume of sterile PBS. Sampling was conducted 24 h after challenge. Results showed that gavage of E. coliNissle 1917 reduced the spleen index, Salmonellaloads, and inflammation (P < 0.05). It improved intestinal morphology and intestinal barrier function (P < 0.05). S.Enteritidis infection significantly reduced mRNA expression of angiotensin-converting enzyme 2 (ACE2) and solute carrier family 6-member 19 (SLC6A19) in the cecum and the content of Gly, Ser, Gln, and Trp in the serum (P < 0.05). Pretreatment with E. coliNissle 1917 yielded mRNA expression of ACE2and SLC6A19in the cecum and levels of Gly, Ser, Gln, and Trp in the serum similar to that of uninfected chicks (P < 0.05). Additionally, E. coliNissle 1917 altered cecum microbiota composition and enriched the abundance of E. coli, Lactobacillales, and Lachnospiraceae. These findings reveal that the probiotic E. coliNissle 1917 reduced S.Enteritidis infection and shows enormous potential as an alternative to antibiotics.

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciensCECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/−), and 2) BA (1.0 × 106 CFU/g of feed) supplementation (+/−). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 106 CFU/g of feed) supplementation (+/−). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus(P = 0.030) and Ruminococcus(P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcusnumbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringensnumbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.

Plant extracts (PE) are gaining increased attention as potential alternatives to in-feed antimicrobials (AM) due to their known antimicrobial activities. This study was conducted to examine the potential of PE, a microencapsulated product composed of eugenol and garlic tincture as an alternative to AM-agent on performance and intestinal health in broilers under necrotic enteritis (NE) challenge. A total of 960 d-old mixed-sex Cobb 500 chicks were randomly distributed to 48-floor pens with 6 treatments replicated 8 times with 20 birds each. The 6 treatments were as follows: UC, unchallenged control; CC, challenged control; PE, challenged group plus PE; AM, challenged group plus AM; FAP, challenged group plus a full dose of AM with PE; HAP, challenged group plus a half dose of AM with PE in starter, grower and finisher phases. Birds in the challenged groups were inoculated with Eimeriaspp. on d 9 and Clostridium perfringenson d 14. The body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and livability of birds were compromised, and intestinal lesions and mortality were increased (P < 0.05) by NE challenge, illustrating a successful clinical NE challenge. Birds fed AM had higher BWG and FI, and lower FCR, mortality, and intestinal lesions compared to the CC group (P < 0.05). Birds fed PE had improved FCR (P < 0.05) and livability (5.8%) in an overall period compared to the CC group. On d 16, PE supplementation reduced ileal lesion scores in only male birds (P < 0.05). Birds fed PE had decreased Eimeria maximaand Eimeria acervulinaoocyst counts in caecal content (P < 0.05). Birds fed PE had decreased Escherichia brunettiand total oocyst counts in caecal content, and E. acervulinaoocyst counts in ileal content in only female birds (P < 0.05). On d 35, PE supplementation reduced variation of BW in both male and female birds and increased b∗ value (14.4%) in the thigh. These findings suggest the potential of PE supplementation in diets to improve the performance and intestinal health of birds under clinical NE as indicated by improved FCR, livability, uniformity, reduced ileal lesions, oocyst counts and increased skin yellowness. However, the protective effect of PE may not be apparent in the presence of AM in the feed.

Controlling enteric diseases of broilers is crucial. Among many additives, organic acids (OA) and their blends are gaining attention to combat diseases in the post-antibiotic era. The current study evaluated the potentials of short-chain fatty acids (SCFA) and medium-chain fatty acids (MCFA) blends and/or phenolic compounds on intestinal integrity, intestinal pH, caecal microbiota, and caecal SCFA profiles of broilers under necrotic enteritis (NE) challenge. The additives used were A) a blend of SCFA, MCFA, and a phenolic compound (SMP); B) a blend of free and buffered SCFA with MCFA (SMF); C) a blend of free and buffered SCFA with a high concentration of MCFA (SHM). A total of 1,404 male parental chicks of Ross 308 broilers were randomly allocated to 78-floor pens on hatching day with 6 treatments replicated 13 times with 18 birds per pen. The treatments were: UCC, unchallenged control; CHC, challenged control; BAC, challenged group plus zinc bacitracin; SMP, challenged group plus additive SMP; SMF, challenged group plus additive SMF; SHM, challenged group plus additive SHM. Birds were challenged with field-strain Eimeriaspp. on d 9 and Clostridium perfringenson d 14. Birds challenged with NE increased fluorescein isothiocyanate dextran (FITC-d) concentration in serum, reduced acetate and butyrate concentrations, and increased Bacteroidesand C. perfringensload in the caeca (P< 0.05). Birds fed additives decreased FITC-d from gut to serum, reduced Bacteroides(d 16, P< 0.05) and numerically reduced C. perfringensload compared to CHC group. Birds fed additive SHM had higher concentrations of acetate and butyrate (d 21, P< 0.05) than CHC group but were not different from SMP and SMF groups. All the additives exhibited similar intestinal protection against NE compared to the BAC group indicated by FITC-d concentration in serum, acetate, propionate and butyrate concentrations in the caeca, and caecal bacterial loads except for the C. perfringens(P> 0.05). The SMP group had a higher load compared to BAC (P< 0.05). These findings suggest the promising effects of OA blends as alternatives to BAC to ameliorate the impact of NE challenge of broilers as indicated by improved intestinal health.