Reducing protein and supplementing crystalline amino acids, to alter dietary amino acid profiles in birds challenged for subclinical necrotic enteritis.

Necrotic enteritis (NE) is an infection of the gastrointestinal tract and is estimated to cost the global poultry industry billions of dollars annually. A study was conducted to examine whether reducing the crude protein might offset the severity of NE in broilers experimentally challenged with Eimeria spp. on day 9 and Clostridium perfringens on days 14 and 15. Furthermore, increasing the dietary amino acid (AA) density of the diet was also examined owing to identified benefits of improving performance compromised from low protein (LP) diets or NE. A 2 × 2 × 3 factorial arrangement of treatments at 6 replicates per treatment was used with 972 Ross 308 cockerels fed wheat-sorghum-soy-based diets to 35 D. Factors were NE challenge: no or yes; protein: standard (SP) or LP; and AA density: 100% AA, 115% with only essential AA (115% EAA) increased, and 115% AA with both essential and nonessential AA (115% AA) increased. The performance was measured in grower (days 7-21), finisher (days 21-35), and overall (day 7-35) periods. In addition, on day 16, intestinal lesion score and cecal short-chain fatty acids were measured. Only in nonchallenged birds fed LP diets, 115% AA increased grower feed intake (P < 0.01) and body weight gain (P < 0.05) compared to 115% EAA treatments. Challenge increased jejunal lesions (P < 0.001) with no difference between dietary treatments. Finisher body weight gain was greater in nonchallenged birds fed the 115% AA diets than in challenged birds (P < 0.05). Feeding diets with higher nonessential AA encouraged faster recovery from NE challenge. When fed the SP diets, NE challenge increased cecal butyric acid (P < 0.01) and total short-chain fatty acids (P < 0.05). The nutrient matrix used in LP diets does not favor beneficial butyric acid-producing bacteria. Using LP diets to mitigate NE severity does not offset the predisposing effect of E. spp. when attacking the gastrointestinal tract, and NE recovery is favored when feeding SP diets or additional AA.

Nanoselenium prevents eimeriosis-induced inflammation and regulates mucin gene expression in mice jejunum.

BACKGROUND: Although elemental selenium has been found to be effective against Eimeria, no study has yet investigated the effects of selenium nanoparticles (SeNPs) on the Eimeria parasite. The aim of this study, therefore, was to evaluate the ameliorative effect of SeNPs compared with elemental selenium on mice jejunum infected with sporulated oocysts of Eimeria papillata. METHODS: The mice were divided into 4 groups, with the first being the non-infected, control group, and the second, third, and fourth groups being orally inoculated with 1,000 sporulated oocysts of E. papillata. The third and fourth groups also received, respectively, an oral dose of 0.1 mg/kg sodium selenite and 0.5 mg/kg SeNPs daily for 5 consecutive days. RESULTS: The infection induced severe histopathological jejunal damage, reflected in the form of destroyed jejunal mucosa, increased jejunal oxidative damage, a reduction in the number of jejunal goblet cells, and increased production of pro-inflammatory cytokines, quantified by real-time polymerase chain reaction. Treatment of mice with SeNPs significantly decreased the oocyst output in the feces by ~80%. Furthermore, the number of parasitic stages counted in stained jejunal paraffin sections was significantly decreased after the mice were treated with SeNPs. In addition, the number of goblet cells increased from 42.6±7.3 to 95.3±8.5 cells/10 villus-crypt units after treatment. By day 5 post-infection with E. papillata, SeNPs could be seen to have significantly increased the activity of glutathione peroxidase from 263±10 to 402.4±9 mU/mL. Finally, SeNPs were able to regulate the gene expression of mucin 2, interleukin 1ß, interleukin 6, interferon-γ, and tumor necrosis factor α in the jejunum of mice infected with E. papillata. CONCLUSION: The results collectively showed that SeNPs are more effective than sodium selenite with regard to their anti-coccidial, anti-oxidant, and anti-inflammatory role against eimeriosis induced in the jejunum of mice.

Impact of a Macleaya cordata-derived alkaloid extract on necrotic enteritis in broilers.

Necrotic enteritis (NE) causes significant economic losses in the broiler chicken industry, especially in birds raised without in-feed antibiotics. A standardized blend of plant-derived isoquinoline alkaloids (IQA) derived from Macleaya cordata has shown to have anti-inflammatory potency and promoted animal productivity. This study investigated the effects of IQA supplementation on broiler chickens under NE challenge. A 2 × 2 factorial arrangement of treatments was employed with factors: NE challenge (no or yes), and additives (no additive or IQA at 0.15 g/kg) in starter, grower, and finisher diets. Birds were challenged with Eimeria spp. on d 9 and 108 to 109Clostridium perfringens on d 14. Each treatment had 7 replicate floor pens with 17 birds each. NE challenge negatively affected growth performance, livability, and carcass traits. Regardless of challenge, IQA increased feed intake and gain on d 24 (P < 0.05) and 35 (P < 0.01) and improved FCR (P < 0.05), flock uniformity (P < 0.01) and breast meat yield (P < 0.001) on d 35. Supplementation of IQA also reduced lesions in the duodenum (P < 0.05), jejunum (P < 0.001), and ileum (P < 0.001). This study suggests that IQA may protect broilers from NE indicating its role as a promising antibiotic alternative.

Dietary inclusion of arabinoxylo-oligosaccharides in response to broilers challenged with subclinical necrotic enteritis.

1. This study investigated the prebiotic properties of arabinoxylo-oligosaccharides (AXOS) produced both in situ and in vitro for their activity against the onset of necrotic enteritis in broiler chickens. 2. A 2 × 3 factorial arrangement was applied, including necrotic enteritis challenge (challenged/unchallenged) and three dietary treatments from d 10 to 21. A wheat-soy commercial-type basal-grower diet was fed with 2% of the wheat proportion replaced by the same amount of either arabinoxylan (AX), AXOS produced from hydrolysing AX with 16 000 BXU (birch xylanase unit) xylanase in vitro or AX fed with 16 000 BXU xylanase (AX + E). Necrotic enteritis (NE) challenge was induced by orally infecting birds with a vaccine strain of Eimeria oocysts at d 9 of age followed by oral gavage of a freshly prepared Clostridium perfringens broth at d 14. 3. The challenge depressed growth performance, induced gross lesions and reduced ileal viscosity at d 10-21. Birds fed on the AXOS diet had numerically less severe gross lesions, improved feed conversion at d 0-16 and lower ileal viscosity at d 16 compared to birds fed on AX. Weight gain of the unchallenged birds ranked as follows in terms of the diets: AXOS > AX + E > AX. AX + E produced a lower ileal viscosity compared to the AX treatment but only led to marginal improvements in performance and intestinal lesion scores. 4. Caecal short-chain fatty acid (SCFA) concentration was higher in birds fed on AXOS and AX + E compared to those fed on AX and was higher in the challenged birds compared to the unchallenged birds. Gizzard pH was lower in birds fed on AX + E compared to those fed on AXOS at d 16. Challenged birds had lower ileum pH compared to the unchallenged birds at d 16 and 21. 5. Results of this study suggest that AXOS appeared to be efficacious prebiotics, as highlighted by improvements in feed conversion ratio and increased SCFA production. Future studies are warranted to elucidate the types of AXOS that are most active against NE and the mechanisms by which different levels of AXOS enhance bird performance.

Heat Production and Energy Efficiency of Broilers Infected With Necrotic Enteritis.

Necrotic enteritis (NE) in poultry is the most important bacterial disease in terms of economic losses. The present study was conducted to evaluate the effect of an experimental challenge with necrotic enteritis on respiration and heat production in birds pretreated with dietary acylated starch or antibiotics (AB) zinc bacitracin (50 mg/kg) plus salinomycin (60 mg/kg). In total, 48 1-day-old Ross 308 male broilers were assigned to floor pens until day 10. On day 11, birds were randomly placed into 16 calorimetric chambers with four replicates of three birds per treatment. Treatments were: control, AB, acetylated high-amylose maize starch (SA), or butyrylated high-amylose maize starch (SB). Birds were NE challenged by inoculation with 5000 sporulated oocysts each of Eimeria maxima and Eimeria acervulina and 2500 sporulated oocysts of Eimeria brunetti on day 9 and Clostridium perfringens (3.8 × 10(8) colony-forming units) on day 14. The results showed that heat production (HP), respiratory quotient (RQ), heat increment, weight gain (WG), feed intake (FI), and livability (LV) of birds fed control, SA, and SB diets were lower than birds fed AB at 19 and 42 hr postinoculation (P < 0.05). At 65 hr postchallenge, increased FI and WG of birds were observed, indicating recovery from NE. During the entire period, from day 14 to day 17, birds fed control, SA, and SB had lower WG, FI, HP, RQ, metabolizable energy intake (MEI), and metabolizable energy (P < 0.01) than those fed AB. The data demonstrate that Eimeria sp. and C. perfringens challenge reduces growth performance, HP, RQ, metabolizable energy, and MEI of birds fed control, SA, and SB but not AB diets.

Timing of predisposing factors is important in necrotic enteritis models.

Since the ban of antimicrobial growth promotors, the importance of necrotic enteritis in broilers increases. Reliable and reproducible infection models are required for pathogenesis studies and product screening. Two major predisposing factors in necrotic enteritis models are fishmeal supplementation to feed and Eimeria infection. However, many unsolved issues regarding these predisposing factors still exist. Therefore, the influence of timepoint of fishmeal administration (onset on day 8 or day 18), timing of coccidiosis challenge (day 15 or day 19) and strain of coccidiosis challenge (field strain vs. commercial vaccine) on the induction of necrotic enteritis lesions was investigated. The birds were inoculated with Clostridium perfringens three times per day for four consecutive days (day 17 until day 20) and were scored for the presence of necrotic enteritis on days 22, 23, 24, 25 and 26. Supplementation of the diet with fishmeal from day 8 onwards increased the likelihood of necrotic enteritis compared to supplementation from day 18 onwards. Birds challenged on day 19 with coccidiosis were more likely to have necrotic enteritis on scoring days 23 and 24 compared to birds challenged on day 15. Differences on other scoring days were less pronounced. Finally, the strain of coccidiosis challenge had little influence on the induction of necrotic enteritis. Findings of this study can help researchers to set up successful necrotic enteritis infection models.

Dietary acylated starch improves performance and gut health in necrotic enteritis challenged broilers.

Resistant starch has been reported to act as a protective agent against pathogenic organisms in the gut and to encourage the proliferation of beneficial organisms. This study examined the efficacy of acetylated high amylose maize starch (SA) and butyralated high-amylose maize starch (SB) in reducing the severity of necrotic enteritis (NE) in broilers under experimental challenge. A total of 720 one-day-old male Ross 308 chicks were assigned to 48 floor pens with a 2 × 4 factorial arrangement of treatments. Factors were a) challenge: no or yes; and b) feed additive: control, antibiotics (AB), SA, or SB. Birds were challenged with Eimeria and C. perfringens according to a previously reported protocol. On d 24 and 35, challenged birds had lower (P < 0.001) livability (LV), weight gain (WG), and feed intake (FI) compared to unchallenged birds. Challenged birds fed SA and SB had higher FI and WG at d 24 and 35 (P < 0.05) compared to birds fed the control diet, while being significantly lower than those fed AB. Unchallenged birds fed SA or SB had higher FI at d 24 and 35 compared to those fed the control diet (P < 0.05). Birds fed SB had increased (P < 0.001) jejunal villus height/crypt depth (VH:CD) ratios at d 15, increased ileal (P < 0.001) and caecal (P < 0.001) butyrate levels at d 15 and 24, and decreased (P < 0.01) caecal pH at d 15. Birds fed SA had increased (P < 0.001) ileal acetate content at d 24 and decreased (P < 0.01) caecal pH at d 15. These results demonstrated that dietary acylated starch improved WG in birds challenged with necrotic enteritis. Depending on the acid used, starch acylation also offers a degree of specificity in short chain fatty acid (SCFA) delivery to the lower intestinal tract which improves gut health.

Effects of dietary selenium on host response to necrotic enteritis in young broilers.

The effects of dietary supplementation of young broiler chickens with an organic selenium (Se) formulation, B-Traxim Se, on experimental necrotic enteritis (NE) were studied. Chickens treated with three Se doses (0.25, 0.50, 1.00 mg/kg) from hatch were orally challenged with Eimeria maxima at 14 days of age followed by Clostridium perfringens to induce NE. Chickens fed with 0.50 mg/kg Se showed significantly increased body weights and antibody levels against NetB, and significantly reduced gut lesions compared with non-supplemented chickens. However, there were no significant differences in Eimeria oocyst shedding between the Se-treated and non-supplemented groups. Levels of IL-1ß, IL-6, IL-8, iNOS, LITAF, TNFSF15, AvBD6, AvBD8, and AvBD13 transcripts were increased in the gut and spleen of at least one of the three Se-treated groups compared with the non-treated group. These results suggest that dietary supplementation of young broilers with Se might be beneficial to reduce the negative consequence of NE.

Dietary sodium selenite affects host intestinal and systemic immune response and disease susceptibility to necrotic enteritis in commercial broilers.

1. This study was to evaluate the effects of supplementary dietary selenium (Se) given as sodium selenite on host immune response against necrotic enteritis (NE) in commercial broiler chickens. 2. Chicks were fed from hatching on a non-supplemented diet or diets supplemented with different levels of Se (0.25, 0.50, and 1.00 Se mg/kg). To induce NE, broiler chickens were orally infected with Eimeria maxima at 14 d of age and then with Clostridium perfringens 4 d later using our previously established NE disease model. 3. NE-associated clinical signs and host protective immunity were determined by body weight changes, intestinal lesion scores, and serum antibodies against α-toxin and necrotic enteritis B (NetB) toxin. The effects of dietary Se on the gene expression of pro-inflammatory cytokines e.g., interleukin (IL)-1ß, IL-6, IL-8LITAF (lipopolysaccharide-induced TNFα-factor), tumour necrosis factor (TNF) SF15, and inducible nitric oxide synthase (iNOS), glutathione peroxidase 7 (GPx7), and avian ß-defensins (AvBD) 6, 8, and 13 (following NE infection) were analysed in the intestine and spleen. 4. The results showed that dietary supplementation of newly hatched broiler chicks with 0.25 Se mg/kg from hatch significantly reduced NE-induced gut lesions compared with infected birds given a non-supplemented diet. The levels of serum antibody against the NetB toxin in the chicks fed with 0.25 and 0.50 mg/kg Se were significantly higher than the non-supplemented control group. The transcripts for IL-1ß, IL-6, IL-8, iNOS, LITAF, and GPx7, as well as AvBD6, 8, and 13 were increased in the intestine and spleen of Se-supplemented groups, whereas transcript for TNFSF15 was decreased in the intestine. 5. It was concluded that dietary supplementation with optimum levels of Se exerted beneficial effects on host immune response to NE and reduced negative consequence of NE-induced immunopathology.

Dietary supplementation of young broiler chickens with Capsicum and turmeric oleoresins increases resistance to necrotic enteritis.

The Clostridium-related poultry disease, necrotic enteritis (NE), causes substantial economic losses on a global scale. In the present study, a mixture of two plant-derived phytonutrients, Capsicum oleoresin and turmeric oleoresin (XT), was evaluated for its effects on local and systemic immune responses using a co-infection model of experimental NE in commercial broilers. Chickens were fed from hatch with a diet supplemented with XT, or with a non-supplemented control diet, and either uninfected or orally challenged with virulent Eimeria maxima oocysts at 14 d and Clostridium perfringens at 18 d of age. Parameters of protective immunity were as follows: (1) body weight; (2) gut lesions; (3) serum levels of C. perfringens α-toxin and NE B-like (NetB) toxin; (4) serum levels of antibodies to α-toxin and NetB toxin; (5) levels of gene transcripts encoding pro-inflammatory cytokines and chemokines in the intestine and spleen. Infected chickens fed the XT-supplemented diet had increased body weight and reduced gut lesion scores compared with infected birds given the non-supplemented diet. The XT-fed group also displayed decreased serum α-toxin levels and reduced intestinal IL-8, lipopolysaccharide-induced TNF-α factor (LITAF), IL-17A and IL-17F mRNA levels, while cytokine/chemokine levels in splenocytes increased in the XT-fed group, compared with the animals fed the control diet. In conclusion, the present study documents the molecular and cellular immune changes following dietary supplementation with extracts of Capsicum and turmeric that may be relevant to protective immunity against avian NE.

Bacillus subtilis PB6 improves intestinal health of broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis.

Necrotic enteritis (NE) is an enterotoxemic disease caused by Clostridium perfringens that results in significant economic losses, averaging damage of $0.05 per bird. The present study investigated the influence of a dietary supplement, Bacillus subtilis PB6, on performance, intestinal health, and gut integrity against C. perfringens-induced NE in broiler birds. Bacillus subtilis PB6 (ATCC-PTA 6737) is a natural strain isolated from healthy chicken gut that has been shown in in vitro to produce antimicrobial substances with broad activity against various strains of Campylobacter and Clostridium species. The animal study was conducted on broiler chickens (Cobb 400) for the period of 35 d using a completely randomized design. The experimental design included 3 treatments groups. Each treatment group contained 6 replicates, 3 male and 3 female, with 12 birds in each replicate. The 3 treatment groups were an uninfected control, an infected control, and an infected group supplemented with B. subtilis PB6 at 500 g/t of feed, containing 5 × 10(11) cfu/kg. Necrotic enteritis was induced in the broiler birds via oral inoculation of 30,000 oocysts of mixed strains of Eimeria species on d 14 followed by C. perfringens (10(8) cfu/mL) on d 19 through 21 of trial. The birds were analyzed for BW gain, mortality, feed conversion ratio (FCR), intestinal lesion score, intestinal C. perfringens counts, and villus histomorphometry. The infected control group showed markedly thickened mucosa, hemorrhages, intestinal lesions, and ballooning of intestine. The supplementation of B. subtilis PB6 reduced the FCR (P < 0.05) and intestinal C. perfringens counts significantly (P < 0.05) compared with the infected control group. It was also observed that B. subtilis PB6 improved villi length by 10.88 and 30.46% (P < 0.05) compared with uninfected and infected control groups, respectively. The group supplemented with B. subtilis PB6 significantly (P < 0.05) increased the villi length to crypt depth ratio by 49.11% compared with the infected group. In conclusion, the supplementation of B. subtilis PB6 not only controlled C. perfringens-induced NE, but also improved intestinal health in the broiler birds.