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.     

Reproduction and treatment of necrotic enteritis in broilers.

A change in ration from one containing 50% fish meal to a standard chick starter containing 10(8) Clostridium perfringens/g of feed resulted in the production of necrotic enteritis in 2-week-old broiler chicks. Lincomycin added to the inoculated ration at a concentration of 20 g/907.2 kg significantly reduced mortality in the chicks. Inoculation of broth cultures of C perfringens directly into the duodenum, using a surgically inserted tetrafluoroethylene resin tube, indicated a relationship existed between the number of C perfringens inoculated and the gross lesions. The disease could be consistently produced by this technique.     

Potential of a mixture of eugenol and garlic tincture to improve performance and intestinal health in broilers under necrotic enteritis challenge

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 dayold 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 Eimeria spp.on d 9 and Clostridium perfringens on 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 maxima and Eimeria acervulina oocyst counts in caecal content(P<0.05).Birds fed PE had decreased Eimeria brunetti and total oocyst counts in caecal content,and E.acervulina oocyst 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 yellowness(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.     

Origin of Clostridium perfringens isolates determines the ability to induce necrotic enteritis in broilers

Since the ban on growth-promoting antibiotics in animal feed in the European Union, necrotic enteritis has become a major cause of mortality in broiler chickens. Despite the importance of the disease, the pathogenesis is still not completely understood. In the current study, Clostridium perfringens strains isolated from healthy flocks and isolates from outbreaks of necrotic enteritis were evaluated for the ability to cause gut necrosis in an intestinal loop model in laying hens and in an experimental infection model in broilers. High, intermediate and low alpha toxin producing strains were chosen from each isolation source. Only the isolates from field outbreaks induced necrotic gut lesions, independent of the amount of alpha toxin produced in vitro. It was also shown that alpha toxin producing isolates from calf hemorrhagic enteritis cases were not able to induce necrotic enteritis in poultry. These results suggest the presence of host specific virulence factors in C. perfringens strains, isolated from chickens with intestinal necrotic enteritis lesions.     

Potential of blended organic acids to improve performance and health of broilers infected with necrotic enteritis

Organic acids (OA) and their blends have been shown to positively affect performance and health of broilers. However, the data in the literature are not consistent. This study examined the potential of blended short-chain fatty acids (SCFA) with medium-chain fatty acids (MCFA) as alternatives to antibiotic growth promoters (AGP) on performance, health and welfare of broilers infected with necrotic enteritis (NE). 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 Ross 308 one-day-old male parental chicks were randomly distributed into 78-floor pens with 13 replicates of 18 birds each. Six treatments were the following: T1, unchallenged control (UCC); T2, challenged control (CHC); T3, challenged group plus zinc bacitracin (BAC); T4, challenged group plus additive SMP; T5, challenged group plus additive SMF; T6, challenged group plus additive SHM. Challenged birds were gavaged with Eimeria spp. on d 9 and Clostridium perfringens EHE-NE18 on d 14. Post NE challenge and cumulatively, BWG, FCR, and nutrient digestibility of birds were compromised (P < 0.05) by NE challenge indicating a successful induction of sub-clinical NE. Additive SHM had higher BWG compared to CHC and BAC groups (P = 0.001; d 10 to 24) but not different from SMP and SMF groups (P > 0.05). All the 3 additive groups had lower FCR compared to CHC (P = 0.001; d 0 to 35), and exhibited similar jejunal lesions (d 16) compared to BAC and apparent ileal protein digestibility (d 21) compared to UCC and BAC groups (P > 0.05). Birds in additive SHM group had a higher concentration of serum IgA compared to all groups (P = 0.001) except additive SMF (P > 0.05; d 21). All the additive groups had lower footpad dermatitis and hock burns compared to CHC (P < 0.05). The findings suggest the potential of blended OA as alternatives to BAC to protect broilers from NE indicated by improved FCR, immunity, digestibility, and bird welfare.     

Dietary supplementation of essential oils and lysozyme reduces mortality and improves intestinal integrity of broiler chickens with necrotic enteritis

The objective of this study was to investigate the individual and combined effects of essential oils (EO; comprised of thymol and carvacrol) and lysozyme on experimental NE in broiler chickens. A total of 320 1-day-old chicks were randomly assigned to five treatment groups: no-challenge control (NC), NC + C. perfringens challenge (CC), CC + 120 mg/kg of EO, CC + 100 mg/kg of lysozyme, and CC + 120 mg/kg of EO + 100 mg/kg of lysozyme. The results showed that EO or lysozyme decreased the mortality, alleviated the gut lesions, inhibited the liver Enterobacteriaceae carriage, and increased the villus height of the ileum compared with CC (p < .05), although the proliferation of C. perfringens in the ileum was not inhibited (p > .05). Moreover, EO or lysozyme was found to decrease the ileal concentration of sialic acid and the Mucin2 mRNA expression (p < .05). However, the blend of EO and lysozyme did not display significant effect on the NE-associated mortality or gut damage in contrast with CC (p > .05). In conclusion, these findings suggest the similar protective effects of EO and lysozyme in NE-associated mortality and intestinal impairment, but their blend did not exhibit ameliorative effect.     

Organic acid blends improve intestinal integrity,modulate short-chain fatty acids profiles and alter microbiota of broilers under necrotic enteritis challenge

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),and(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 Eimeria spp.on d 9 and Clostridium perfringens on d 14.Birds challenged with NE increased fluorescein isothiocyanate dextran(FITC-d)concentration in serum,reduced acetate and butyrate concentrations,and increased Bacteroides and C.perfringens load 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.perfringens load 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.     

肉鸡肠毒综合征的诊断与治疗

近几年来，在商品肉鸡中流行一种以腹泻、粪便含有大量未消化的饲料；严重时粪便呈烂胡萝卜样或烂西红柿状为特征的疫病，导致采食量下降，生长缓慢，饲料报酬降低，严重时造成大批死亡，根据临床表现剖检变化和实验室检验确诊为肉鸡肠毒综合征。现将邳州市禽病门诊部就肉鸡肠毒综合征的发病原因、临床诊断与治疗情况介绍如下，供养殖户参考。     

Fumonisins affect the intestinal microbial homeostasis in broiler chickens,predisposing to necrotic enteritis

Fumonisins (FBs) are mycotoxins produced by Fusarium fungi. This study aimed to investigate the effect of these feed contaminants on the intestinal morphology and microbiota composition, and to evaluate whether FBs predispose broilers to necrotic enteritis. One-day-old broiler chicks were divided into a group fed a control diet, and a group fed a FBs contaminated diet (18.6 mg FB1+FB2/kg feed). A significant increase in the plasma sphinganine/sphingosine ratio in the FBs-treated group (0.21 ± 0.016) compared to the control (0.14 ± 0.014) indicated disturbance of the sphingolipid biosynthesis. Furthermore, villus height and crypt depth of the ileum was significantly reduced by FBs. Denaturing gradient gel electrophoresis showed a shift in the microbiota composition in the ileum in the FBs group compared to the control. A reduced presence of low-GC containing operational taxonomic units in ileal digesta of birds exposed to FBs was demonstrated, and identified as a reduced abundance of Candidatus Savagella and Lactobaccilus spp. Quantification of total Clostridium perfringens in these ileal samples, previous to experimental infection, using cpa gene (alpha toxin) quantification by qPCR showed an increase in C. perfringens in chickens fed a FBs contaminated diet compared to control (7.5 ± 0.30 versus 6.3 ± 0.24 log10 copies/g intestinal content). After C. perfringens challenge, a higher percentage of birds developed subclinical necrotic enteritis in the group fed a FBs contaminated diet as compared to the control (44.9 ± 2.22% versus 29.8 ± 5.46%).

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0234-8) contains supplementary material, which is available to authorized users.     

Replacement of canola meal with Moringa oleifera leaf powder affects performance and immune response in broilers

Moringa oleifera is known as a miracle tree due to its amazing nutritional and therapeutic properties. Considering its nutritional value, Moringa oleifera leaf powder can be used as a non-conventional ingredient in poultry diets. This study was conducted to investigate the effect of the replacement of canola meal (CM) with Moringa oleifera leaf powder (MOLP) on growth performance, blood hematology, and immune response in broilers. Two-hundred-twenty one-day-old Hubbard broiler chicks were reared in one group for a wk (adaptation period). At 8 d of age, 150 chicks of similar body weight (±5g) were selected and randomly divided into 15 experimental units, each comprising 10 chicks. These experimental units were further allocated to 5 treatment groups that were fed Ration A (control), B, C, D, and E, containing 8% CM and 0% MOLP, 6% CM and 2% MOLP, 4% CM and 4% MOLP, 2% CM and 6% MOLP, and 0% CM and 8% MOLP, respectively. The experimental diets were fed to the broilers for a period of 31 d. The results of the present study suggest that replacement of CM with MOLP as a vegetable protein source can enhance the immune response to Newcastle disease and infectious bursal disease vaccination without any change in weight gain, body organ weight, and blood hematology in broilers. The results also indicate that replacement of CM with MOLP results in higher feed intake with some negative effects on FCR in broilers.     

人参茎叶总皂苷联合亚硒酸钠对猪伪狂犬病灭活疫苗免疫的增强作用

为了探讨人参茎叶总皂苷(ginseng stem-leaf saponins,GSLS)联合亚硒酸钠(Na2SeO3,简称Se)对伪狂犬病病毒(PRV)灭活疫苗免疫的增强作用,本试验给小鼠口服GSLS后,接种添加了Se的PRV灭活疫苗,并检测免疫后小鼠血清中PRV gB抗体及其亚类(IgG1和IgG2a)水平、淋巴细胞...     

雏鸡坏死性肠炎的诊治报告

雏鸡坏死性肠炎是由产气荚膜杆菌(也叫魏氏梭菌)引起的一种急性或慢性传染病。本病主要感染2～4周龄的雏鸡,其它月龄的鸡也有发生。2004年5月,辽宁省盘锦市一养鸡户饲养的罗曼蛋鸡2500只,10日龄时,发生一种以消瘦、食欲减退或废绝、排浓血便、小肠段出血性坏死为特征的传染病,经临床观察、病理剖检和实验室诊断,确诊为雏鸡坏死性肠炎。     

Dietary organic acid and fiber sources affect performance,intestinal morphology,immune responses and gut microflora in broilers

This experiment was designed to investigate the effects of a dietary organic acid (OA) mixture and 2 fiber sources on performance, intestinal morphology, immune responses and gut microflora in broilers. A total of 390 one-day-old broiler chicks (Ross 308) were allocated to 6 dietary treatments with 5 replicate pens and 13 chicks each based on a factorial arrangement (2 × 3) in a completely randomized design. The experiment lasted 42 d. The following experimental diets and as well as their interaction were considered: a basal diet supplemented with or without OA (0 or 1 g/kg) and 2 fiber sources (sugar beet pulp [soluble fiber] or rice hull [insoluble fiber]; 0 or 30 g/kg). Dietary supplementation of OA increased daily weight gains of broilers across the entire rearing period (P < 0.05). The dietary fibrous materials did not affect the performance of broilers. Antibody titer against influenza disease virus was higher in birds fed diets containing rice hull compared with other experimental groups (P < 0.05). The population of Lactobacillus bacteria was greater in birds fed OA-added diets without or with 30 g/kg rice hull supplementation compared with other experimental groups (P < 0.05). In conclusion, dietary supplemental OA improved performance of broilers, and dietary supplemental OA with rice hull enhanced humoral immune responses.     

Products to alleviate the effects of necrotic enteritis and aflatoxin on growth performance,lesion scores,and mortality in young broilers

This study investigated the effects of necrotic enteritis challenge or a necrotic enteritis challenge with an additional challenge from dietary aflatoxin B₁ compared to broilers that were unchallenged. Also tested were products designed to help alleviate those effects. Lesion scores were higher in broilers challenged to induce necrotic enteritis, but this did not increase with added aflatoxin. The presence of dietary aflatoxin during a necrotic enteritis challenge significantly increased the negative effects of the necrotic enteritis challenge. During the necrotic enteritis challenge virginiamycin, Calibrin-Z, or a blend of Calibrin-Z, an organic acid, and yucca, helped to decrease the effects of the challenge. When birds are challenged with necrotic enteritis and dietary aflatoxin is present, Calibrin-Z had an advantage over all other tested products.     

The immune response to dietary antigens and its influence on disease susceptibility in farm animals

Transient hypersensitivity reactions of the intestinal immune system to dietary antigens result in increases in enterocyte turnover and villous atrophy. These changes occur in the intestine of the post weaned piglet and precede the proliferation of E. coli and the development of post-weaning diarrhea. We therefore postulated that a transient cell mediated immune response to dietary antigens may increase susceptibility to disease. The interaction of dietary and microbial antigens upon the gut immune system has been investigated in mice and pigs and it has been shown that both exert powerful regulatory effects upon each other.     

Effects of different dl‐selenomethionine and sodium selenite levels on growth performance,immune functions and serum thyroid hormones concentrations in broilers

This trial was conducted in a 2 × 3 + 1 factorial arrangement based on a completely randomized design to evaluate the effects of different dl ‐selenomethionine (dl ‐Se‐Met) and sodium selenite (SS) levels on growth performance, immune functions and serum thyroid hormones concentrations in broilers. A total of 840 Ross 308 broilers (7 days old) were allocated by body weight to seven treatments (three replicates of 40 birds each treatment) including (1) basal diet (containing 0.04 mg of selenium (Se)/kg; control) without supplementary Se; (2, 3 and 4) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as SS; (5, 6 and 7) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as dl ‐Se‐Met. The experiment lasted 42 days. The results revealed that dietary Se supplementation improved (p < 0.05) average daily gain, feed efficiency, immune organ index, serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM) and triiodothyronine (T₃) concentrations and decreased (p < 0.01) thyroxine (T₄)/T₃ ratio in serum compared with the control. Broilers receiving the dl ‐Se‐Met‐supplemented diets had higher (p < 0.05) feed efficiency, thymus index, the amounts of IgA, IgG, IgM and T₃ as well as lower (p < 0.05) serum T₄ concentrations and T₄/T₃ ratio than those consuming the SS‐supplemented diets. Serum IgA and IgM levels of broilers fed 0.15 mg Se/kg were significantly higher (p < 0.05) than those of broilers fed 0.05 or 0.25 mg Se/kg. In summary, we concluded that dl ‐Se‐Met is more effective than SS in increasing immunity and promoting conversion of T₄ to T₃, thus providing an effective way to improve the growth performance of broilers. Besides, based on a consideration of all experiment indices, 0.15 mg Se/kg was suggested to be the optimal level of Se supplementation under the conditions of this study.     

Dietary hydrolysed yeast cell wall extract is comparable to antibiotics in the control of subclinical necrotic enteritis in broiler chickens

ABSTRACT

1. The aim of this study was to examine the effect of yeast cell wall (YCW) on performance and physiological responses of broiler chickens under subclinical necrotic enteritis challenge.

2. Six treatments in a 2 × 3 factorial arrangement (non-challenged or challenged plus no supplement, YCW or antibiotics (AB)) was used. Each treatment was replicated eight times with 12 birds per replicate. The treatments included: (1) Positive control (PC; no additive, not challenged); (2) Negative control (NC; no additive, with challenge); (3) YCWN = yeast cell wall (2.0 g/kg diet, not challenged; (4) YCWC = yeast cell wall (2.0 g/kg diet, challenged); (5) ABN = zinc bacitracin 50 ppm + Salinomycin 60 ppm, not challenged); (6) ABC = zinc bacitracin 50 ppm + Salinomycin 60 ppm, challenged).

3. Eimeria challenge at 9 d of age did not affect feed intake (FI), body weight gain (BWG), FCR or liveability at 10 d. The BWG and FCR at 10 d were greater (P < 0.05) in birds fed YCW or AB (AB) diets relative to the PC or NC groups. On 24 and 35 d, FI, BWG, FCR and flock uniformity (28 d) were greater (P < 0.05) in the challenged groups fed YCW or AB diets compared to NC group.

4. Supplementation with YCW ameliorated the negative effects of NE on liver, spleen and bursa weight of birds.

5. Necrotic enteritis challenge decreased (P < 0.05) caecal Lactobacillus and Bifidobacterium spp. counts, and increased ileum lesion score and caecal Clostridium perfirngens counts. This was reversed by the addition of either YCW or AB.

6. Supplementation with YCW and AB resulted to a greater (P < 0.05) dressing percentage and meat yield (35 d).

7. The results indicated that YCW plays a vital role in improving the physiological response and performance of broiler chickens under subclinical necrotic enteritis challenge.     

Interaction between genotype and dietary concentrations of methionine for immune function in commercial broilers

1. Growth, antibody response to sheep red blood cells (SRBC) and resistance to Escherichia coli were measured in broiler female chicks received from 4 (n = 100 in each) commercial genotypes (A, B, C and D) and fed with maize-soybean-deoiled rice bran based diets containing 4 concentrations of methionine (3.91, 4.46, 5.00 and 5.54 g/kg). The diets were fed ad libitum from 1 to 49 d of age. 2. Body weight gain and weight gain/food intake at 2 week intervals, response of broilers to inoculation of 0.5 ml of SRBC (0.5 or 2.5%), 0.1 ml of E. coli (10(-4) dilutions) culture, and 100 microg phytohaemogglutinin-P (PHA-P) at 43 d of age were measured. The responses to SRBC and E. coli inoculation were recorded at 5 d post inoculation (PI), while the responses to PHA-P were recorded at 12 and 24 h PI. 3. Genotype by methionine interaction was not significant for body weight gain, but significant differences in weight gain were observed among different genotypes. Variation in methionine concentration did not influence body weight gain or weight gain/food intake at 1 to 14, or 42 d of age. At 28 d of age, chicks fed on the 3.91 g methionine/kg diet weighted significantly less than those on the other methionine concentrations. Genotype by methionine interaction was observed for food efficiency at 0 to 28 d of age but not at other ages. 4. Antibody titres against SRBC and heart and air sac lesion score to E. coli challenge were not influenced by genotype-methionine interaction. Chicks given higher concentrations of methionine had higher antibody titres and greater cutaneous basophilic hypersensitivity (CBH) response than those given low levels of methionine. Also, variation was observed in expression of CBH response to PHA-P among different genotypes. 5. It may be concluded that, although the commercial broiler chicks do not require more than 3.91 g methionine/kg for optimum growth and food efficiency, the immunity in terms of CBH response and antibody production to SRBC increased with the concentration of methionine in the diet in the majority of genotypes, indicating a higher methionine requirement for immunity than for weight gain.