Efficacy of narasin in the prevention of necrotic enteritis in broiler chickens

The efficacy of narasin in the control of necrotic enteritis (NE) was investigated in a floor pen study of 2000 broiler chickens using a Clostridium perfringens feed inoculum challenge model. Treatments were 1) nonmedicated, nonchallenged; 2) nonmedicated, challenged; 3) narasin, nonchallenged; 4) narasin, challenged. Narasin was administered at 70 ppm in the feed from day 0 to trial termination on day 41. Challenge inoculum contained approximately 1 x 10(8) colony-forming units CP/ml and was administered from day 14 to day 16. In the unmedicated groups, challenged birds had significantly (P < 0.05) lower mean body weight and reduced feed efficiency at day 21 and significantly (P < 0.01) higher cumulative NE mortality at day 41 compared with unchallenged. Similarly, among unmedicated birds, those challenged had a significantly (P < 0.01) higher mean NE score on day 17 and significantly (P < 0.05) higher mean huddling scores on days 15-17 than unchallenged. Among challenged birds, those fed narasin had significantly (P < 0.05) higher mean body weight and improved feed efficiency at days 21 and 41 and significantly (P < 0.01) lower cumulative NE mortality at day 41 than unmedicated. Similarly, among challenged birds, those receiving narasin had a lower mean NE score on day 17 (P > 0.05) and significantly (P < 0.05) lower huddling scores on days 16 and 17 than unmedicated. Coccidiosis lesion scores were zero for birds euthanatized from all treatment groups on day 17, suggesting that the beneficial effects of narasin were not due to prevention of coccidiosis. This study thus provides evidence that narasin is effective in the prevention of necrotic enteritis in broiler chickens.     

Coccidiosis control with toltrazuril in conjunction with anticoccidial medicated or nonmedicated feed

A 42-day broiler floor pen study was conducted comparing the anticoccidial efficacy of toltrazuril (Baycox) as a stand alone treatment and as an additional treatment to in-feed anticoccidial programs. Toltrazuril was administered on days 18 and 19 in the drinking water at 7 mg/kg of body weight. The treatments were 125 ppm nicarbazin (days 0-14) to 66 ppm salinomycin (SAL) (days 15-35) with and without toltrazuril, SAL (days 0-35) with and without toltrazuril, nonmedicated (NM) to SAL with toltrazuril, and NM with and without toltrazuril. The controls were NM noninfected and infected. The treatments were replicated in five blocks of eight pens each in a randomized complete block design. All withdrawal feed was nonmedicated. On day 14, birds, except noninfected, were exposed to coccidial oocysts (Eimeria acervulina, Eimeria maxima, and Eimeria tenella) seeded litter. On days 21, 28, 35, and 42, birds and feed were weighed, four birds per pen were coccidial lesion scored, and litter oocyst counts were performed. The coccidial infection in the NM infected treatment caused a significant (P < 0.05) coccidiosis infection. Coccidiosis was moderately controlled in the anticoccidial treatment birds without toltrazuril. Performance in the NM with toltrazuril was equal to or better (P < 0.05) than the anticoccidial programs without toltrazuril. Toltrazuril was equal to the noninfected birds in performance. Toltrazuril most completely eliminated all coccidial lesions and dramatically reduced oocyst shedding. The performance data, lesion scores, and oocyst counts showed that a 2-day treatment with toltrazuril successfully controlled the coccidiosis with no relapse of infection. Toltrazuril can thus be used for supplemental control with in-feed anticoccidials or as a primary anticoccidial with nonmedicated feed.     

Dietary supplementation of phenyllactic acid on growth performance,immune response,cecal microbial population,and meat quality attributes of broiler chickens

A total of 750 one-day-old male broiler chicks were randomly fed 5 dietary treatments with 5 replicate pens per treatment. The 5 dietary treatments fed for 42 d were a corn-soybean meal basal diet without antibiotic (control); a mixture of 10 ppm of avilamycin + 60 ppm of salinomycin as antibiotic growth promoters (AGP); 0.1% phenyllactic acid (PLA); 0.2% PLA; and 0.4% PLA. The BW gain and FE were significantly improved in AGP and PLA groups compared with control group. The white blood cells and heterophil counts were significantly higher in the PLA-supplemented groups compared with AGP and control groups, but the heterophil-to-lymphocyte ratio was lower in the control group than other groups. The plasma IgY concentration was significantly increased in birds fed PLA-supplemented diets, but the plasma IgA and IgM concentrations were not different among the treatment groups. In addition, the antibody titer against Newcastle disease virus was significantly higher in PLA-treated compared with control and AGP-treated groups. Neither PLA nor AGP treatments affected the cecal aerobes andSalmonella content; however, cecalLactobacillus population increased in chickens fed 0.1% PLA, and total coliform bacteria population significantly decreased in chickens fed various levels of PLA and AGP. Dietary supplementation of PLA did not affect the pH, lightness, and redness of breast meat, but the water-holding capacity and shear force value increased and the yellowness decreased significantly when birds were fed PLA. It was concluded that dietary supplementation of 0.1 and 0.2% PLA improves BW gain and FE of broiler chickens. In addition, PLA supplementation increases the immune characteristics and the number of lactic acid bacteria, decreases the number of coliform bacteria, and improves the meat quality attributes of broiler chickens. Thus, dietary PLA could be a viable alternative to antibiotics in broiler diets.     

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.     

β-1,3-葡聚糖对感染大肠杆菌肉鸡肠道氧化还原状态、菌群状态和免疫功能的影响

试验选择90只1日龄AA肉鸡随机分成3组,分别饲养于隔离器中。处理1和2饲喂基础日粮,处理3饲喂添加葡聚糖的试验日粮。处理2和3在8、9和10日龄连续口服感染大肠杆菌O780.5mL(浓度为1×1010cfu/mL)。处理1组鸡在8、9和10日龄口腔接种等剂量的灭菌PBS。结果表明,大肠杆菌O78感染会显著降低鸡生长速度(P<0.05),提高死亡率,使感染初期小肠氧化损伤,显著降低肠道乳酸菌数和肠道sIgA量(P<0.05),但显著提高感染初期血清特异性IgG和感染后期空肠sIgA和血清特异性IgG水平(P<0.05)。而日粮添加葡聚糖降低肉鸡死亡率,缓解因感染引起的生长速度降低,减轻肠道氧化损伤,增强肠黏膜抗氧化能力,显著提高感染后期肠道乳酸细菌数量和感染后期血清特异性IgG水平。     

Pathology and histology of dietary tryptophan deficiency in broiler chicks

The purpose of this experiment was to characterize a lesion of the rhamphotheca associated with tryptophan (TIRP) deficiency, search for other histological abnormalities,and determine whether bird size and housing conditions are contributing factors to these lesions. Day-old broiler chicks (Ross X Ross 308) were placed in either floor pens with fresh pine shavings or Petersime battery brooders with two pens of 10 chicks each per treatment. Broiler chicks from 0 to 21 days of age were fed adequate (0.24%) and deficient (0.09%) levels of TRP in diets based on corn, corn gluten meal, and gelatin. Separate groups of control chicks were pair fed daily with the deficient chicks. Deficient chicks grew less efficiently than did the pair-fed controls. Upon gross examination, a lesion of the maxillary rhamphotheca in the vicinity of the nares was observed in 61% of TRP-deficient birds housed in the battery and 13% of the birds housed in floor pens. A similar gross lesion was only observed in one control bird. These lesions were located along the upper portion of the beak between the nares and appeared as a crusty or scab-like area on gross examination, composed of detritus, heterophils, and plasma protein. Inflammation occasionally was observed at the dermoepidermal junction. The incidence of lesions was reduced in floor pens compared to battery brooders, but similarly sized birds did not exhibit the lesion. The number of lesions seen grossly and histologically in TRP-deficient birds, as compared to control birds, supports the hypothesis that TRP deficiency is the primary cause of these lesions around the nares of broilers. Secondary environmental factors, perhaps coprophagy, also influence the incidence of the lesion.     

Effect of dietary supplementation of probiotic on the performance of F1 crossbred (Rhode Island red male × Fayoumi female) cockerels

A study was conducted to evaluate four different probiotic levels, using diets supplemented with 0 (control), 0.1%, 0.2%, 0.3% or 0.5% of organic-green culture-zs (probiotic). The cockerels of 6-weeks old were randomly divided into 15 separate floor pens each comprising 25 birds and three pens (replicates) per treatment group following completely randomized design. At 12 weeks of age BW and feed to gain ratio (FCR) were determined. At the end of 42 days of experiment, nine birds per treatment were sacrificed to evaluate carcass characteristics, abdominal fat contents and the internal organs. Blood haemato-biochemical parameters were also determined. Haemagglutination inhibition antibody titres against Newcastle disease virus and lymphoid organs weight/body weight ratio were also determined. The BW of birds fed 0.2-0.5% of probiotic was significantly greater than birds fed without probiotic diet. Similarly, better FCR was observed in birds those fed diets of high level of probiotic. There was no mortality recorded at higher levels of probiotics. Differences in carcass characteristics, organs weight, meat composition, haematological values and HDL and LDL concentrations among all the diets were non-significant. However, abdominal fat contents reduced significantly in supplemented groups in relation to control and cholesterol contents were reduced significantly in 0.3% or 0.5% supplemented groups in relation to control. Feeding levels of 0.2-0.5% of probiotic, did positively affect the immune system within the parameters measured. It may be concluded that performance, blood chemistry and immunity against disease in cockerels could be maintained when supplementing 0.3% or 0.5% level of probiotic incorporated in crossbred cockerel's diets.     

Effect of High-Protein and All-Vegetable Diets on the Incidence and Severity of Pododermatitis in Broiler Chickens

The incidence and severity of pododermatitis in broiler chickens is of great concern to the broiler industry, both from product quality and animal welfare standpoints. A total of 1,600 birds were raised in floor pens in a design involving a 2 × 2 × 2 arrangement of protein level [high or low], protein source [all vegetable (VEG) or vegetable plus animal (VEG + ANI)], and sex (male and female) on a 4-stage feeding program (50 birds per pen; 4 pens of males and 4 pens of females per treatment). In addition to live performance, the feet were scored on all birds on 29, 43, and 54 d of age, and the severity of lesions was recorded as none, mild, or severe. A subsample of birds was processed at the end of the experiment to evaluate carcass yields. Pooled litter samples were collected on 29, 43, and 54 d of age for total and NH₃-N analysis. Protein level had a significant (P < 0.05) effect on BW on 14, 29, and 43 d of age. At 43 and 54 d of age, BW was significantly influenced by protein source and sex. Chilled carcass yields did not differ between the treatments (P > 0.05). Footpad lesions were significantly affected by protein level, protein source, and sex. At 29 d of age, all lesions were mild in severity and varied significantly in incidence by protein source (31% for VEG vs. 41% for VEG + ANI). At 54 d of age, both protein level and protein source significantly increased the incidence and severity of footpad lesions. Incidence of pododermatitis was higher for males (61%) than females (55%). Litter total N was significantly affected by protein level and protein source. The litter NH₃-N content, although not significant, except for 29 d of age, showed an increasing trend for each feeding period. The incidence and severity of pododermatitis was significantly affected by protein level, protein source, sex, and age. Hence, nutritional factors play a significant role in the etiology of pododermatitis in broilers.     

Effect of a radiant energy-treated lysozyme antimicrobial blend on the control of clostridial necrotic enteritis in broiler chickens

A cage study was conducted to demonstrate the effect of Entegard REV, a lysozyme-based antimicrobial blend, on the performance of broiler chickens and necrotic enteritis (NE) disease reduction of birds that were challenged with Eimeria maxima and Clostridium perfringens. In the experiment, challenge by the infectious agents without medication resulted in impaired feed consumption, weight gain, and feed conversions and caused high incidence of gross NE lesions and NE mortality rate. Entegard REV included in feed at 200 g/metric ton (MT) was very effective in reducing negative health effects in the birds after NE challenge, and its ability to control the disease was not statistically different from a commonly used antibiotic growth promotant, bacitracin methylene disalicilate, at 55 g/MT.     

L．fermentum1．2029对坏死性肠炎肉鸡回肠上皮紧密连接蛋白表达的影响

将240只AA肉鸡随机分为3个处理组：对照组、坏死性肠炎（Necrotic enteritis,NE）模型组及乳酸杆菌处理组。28日龄,每组屠宰24只鸡,对各组肉鸡肠道损伤进行肉眼评分,并采集回肠黏膜样本分别用于电镜下形态观察和Real—timePCR检测紧密连接蛋白claudin-1和occludin的表达。结果显示,乳酸杆菌处理组降低了炎症的损伤程度（P〈0．05）;电子显微镜观察显示,乳酸杆菌处理组鸡回肠上皮微绒毛较NE模型组有改善;real—timePCR分析显示,乳酸杆菌处理组claudin-1和occludin的表达显著高于NE模型组（P〈0．05）,但与对照组没有差异。该试验结果表明,L．fermentum1．2029可降低NE的损伤程度,并能有效上调NE条件下claudin-1和occludin的表达,显示其具有保护肠道屏障功能的作用。     

Effects of phytonutrients on growth performance,antioxidative status,and energy utilization of broilers fed low energy diets

Two experiments were conducted to investigate the effects of phytonutrients (PN) on growth performance, antioxidant status, intestinal morphology, and nutrient utilization of birds fed low energy diets. In Exp. 1, a total of 1,440 one-day-old Ross 308 male broiler chickens were randomly divided into 3 treatment groups, with 16 replicates per treatment (48 pens; 30 birds per pen). Birds in treatment 1 were fed diets with normal energy content (NE). Birds in treatment 2 were fed NE diet but with 60 kcal removed (LE). Birds in treatment 3 were assigned to LE diet supplemented with PN (LE + PN). Results indicated that LE diet increased feed conversion ratio (FCR) compared with NE from d 1 to 38, while LE + PN diet prevented this response (P = 0.02). At d 26, birds in the LE + PN group had the highest ileal and jejunal villus height to crypt depth (VH:CD) ratio. At d 39, PN supplementation improved ileal and jejunal VH:CD ratio, compared with LE group. Moreover, birds fed PN diets received a better economic profit. In Exp. 2, 360 one-day-old Ross 308 male broiler chickens were used in a metabolism study. The treatments used in Exp. 2 were the same as those in Exp.1, with 4 replicates (pens) and 30 birds in each replicate. Dietary apparent metabolism energy (AME), energy and protein digestibility were determined between 21 and 28 d of age. Results showed that chickens fed LE + PN diet tended to have greater AME (P = 0.02) and nitrogen-corrected apparent metabolism energy (AMEn) (P = 0.03) than birds fed LE diets. It was concluded that LE + PN showed a potential advantage to improve feed conversion and gut health of broilers, as well as economic profits.     

Differences in the pathogenicity of various bacterial isolates used in an induction model for gangrenous dermatitis in broiler chickens

A gangrenous dermatitis model was developed in broiler chickens, in which birds previously vaccinated at 14 days of age with a bursal disease virus vaccine were challenged at 4 wk of age with various bacterial combinations with the combination of subcutaneous and intramuscular injection. Gangrenous dermatitis lesions were not produced in birds injected with one of the Staphylococcus aureus isolates, either alone or in combination with various Clostridium septicum isolates. Other S. aureus isolates produced significant levels of gangrenous dermatitis either alone or in combination with the same C. septicum isolates. These same C. septicum isolates when given alone did not produce gangrenous lesions. Data from this experiment show the highest level of mortality occurred in birds challenged with a mixture of C. septicum and S. aureus isolates, whereas lower or no mortality was associated with the same isolates given separately. The data clearly demonstrate that the pathogenicity of isolates responsible for gangrenous dermatitis varies widely, indicating that the frequency and severity of lesion production, as well as the occurrence of mortality, are largely dependent upon the specific isolate or isolates with which the birds are challenged.     

Effect of Continuous Multiphase Feeding Schedules on Nitrogen Excretion and Broiler Performance

Two experiments were conducted simultaneously to evaluate the effects of continuous multiphase feeding programs on nitrogen excretion and broiler performance. Birds in both experiments were fed diets based on 1 of 3 unique feeding schedules. One feeding program consisted of an industry-type 4-phase schedule, whereas the remaining treatments consisted of diets that were blended and replaced every 3 d. One of these continuous multiphase feeding programs was based on industry average nutrient compositions, whereas the other feeding program was based on the EFG Broiler Growth Model. In experiment 1, 60 one-day-old male broiler chicks were randomly placed in 30 separate battery brooding pens with 3 unique feeding schedules (10 replicates per treatment). Nitrogen analyses were conducted on broiler excreta and ground, whole birds. Experiment 2 was conducted to evaluate the effects of continuous multiphase feeding programs on broiler performance in floor pens. A total of 540 one-day-old male broiler chicks were placed in 36 pens, yielding 12 replicates of 3 treatments. Continuous multiphase feeding schedules improved BW gain and the feed-to-gain ratio during wk 3 and 4 (experiment 1) and wk 5 and 6 (experiment 2). Nitrogen excretion and retention, however, were unaffected by the different feeding programs.     

Performance comparison between the use and nonuse of an enteric health medication program across five consecutive commercial broiler flocks

A study was conducted to examine broiler performance and carcass yield across 5 consecutive commercial broiler flocks after the removal of roxarsone (ROX) and growth-promoting antibiotics (GPA) from the feed. Over a 1-yr period, approximately 552,000 broilers were reared in 4 solid-walled, tunnel-ventilated houses, divided into 2 paired-house facilities, and were assigned 1 of 2 dietary treatments. The treated group received basal diets containing salinomycin, ROX, and GPA, whereas the control group received the same diets without ROX and GPA. Average BW were recorded for 200 sample birds/treatment per flock at 18, 35, and 48 d of age. Average BW, feed conversion, adjusted feed conversion, livability, and condemnation were calculated at the completion of each flock. Coccidiosis lesion scores of 10 birds per treatment were recorded at 14, 21, 28, 35, and 42 d of age. Before birds were transferred to a commercial processing plant, 280 birds/flock were randomly selected, weighed, and tagged for carcass yield analysis. Livability was significantly negatively affected by the removal of ROX and GPA. Coccidiosis lesion scores were not affected by the treatments. Tender yields showed significant improvement, whereas all other cuts were not affected by removal of ROX and GPA.     

Comparative efficacy of enrofloxacin, oxytetracycline, and sulfadimethoxine for the control of morbidity and mortality caused by Escherichia coli in broiler chickens

The purpose of the present study was to compare the ability of enrofloxacin, oxytetracycline, and sulfadimethoxine to reduce morbidity and mortality caused by Escherichia coli (colibacillosis) in broiler chickens. The chickens were raised in 80 pens (20 birds per pen) with 20 pens representing each treatment group under simulated commercial conditions that produced a colibacillosis challenge scenario. Each group of 20 randomized pens (replicates) was given one of four water treatments. Chickens that received enrofloxacin had significantly less mortality (P < 0.01), lower average gross pathology (colibacillosis) scores (P < 0.01), and better feed-conversion ratios (P < 0.05) than did chickens that received either oxytetracycline or no medication. Chickens that received enrofloxacin had significantly less mortality and lower pathology scores than those that received sulfadimethoxine and numerically lower feed conversion than the sulfadimethoxine group. Results from the present study show that enrofloxacin is superior to oxytetracycline and sulfadimethoxine for the control of morbidity and mortality caused by E. coli in broiler chickens. Our findings will help veterinarians choose and prescribe the most efficacious antimicrobial when treating colibacillosis.     

Guar meal ameliorates Eimeria tenella infection in broiler chicks

Guar meal contains relatively high levels of saponins, which are known to have antiprotozoal activity and may be effective against coccidiosis. A 2x2 factorial experiment investigated the impact of guar meal (0 or 5%) corn-soy-based starter broiler diets on chicks unchallenged or challenged with Eimeria tenella. At 1 day of age, 120 unsexed RossxRoss broiler chicks were randomly distributed among four treatment groups. Chicks were challenged with 5x10(3) sporulated oocysts of E. tenella in 0.5ml at 10 days of age by oral gavage. Weekly body weight, body weight gains, feed conversion ratio and mortality rate were recorded for chicks fed from 0 to 21 days of age. Oocysts shed per gram feces were recorded from 6 to 10 days post-challenge. Results showed that challenged chicks fed 0% guar meal had significantly higher oocysts per gram shed in feces than the other groups. No significant differences among treatment groups in mortality rate were observed. Body weights of unchallenged and challenged chicks fed 0% guar meal were significantly higher than those fed 5% guar meal at 2 weeks of age. Results indicated that including 5% guar meal in the diet of chicks challenged with E. tenella decreased oocysts shed per gram feces and prevented bloody diarrhea, but without affects on body weight and feed conversion ratio at 11 days post-challenge.     

Wet litter not only induces footpad dermatitis but also reduces overall welfare,technical performance,and carcass yield in broiler chickens

This study investigated whether a high level of footpad dermatitis (FPD) in broiler chickens induced by increased litter moisture content is accompanied by negative effects on technical performance, carcass yield, and other welfare aspects. Litter moisture content was increased by systematically spraying water over the litter from 6 d of age onward (lesion-induction treatment). Results were compared with a control group kept on relatively good quality litter and having a very low prevalence of footpad lesions. Litter quality significantly decreased from 7 d of age onward in the pens with the lesion-induction treatment compared with the control pens. At 21 and 36 d of age, significantly more FPD was observed in the lesion-induction groups compared with the control groups. Technical performance of the broilers was negatively affected for the lesion-induction groups from 28 d of age onward; lesion-induction groups had significantly lower BW gain, feed intake, and water intake and significantly higher FCR compared with control groups. As a result of the lower BW gain, carcass weight was less for the lesion-induction group and significantly more rejections for commercial parts were found. The lesion-induction groups also had significantly more hock burns and breast irritations at d 21 and 36, and were dirtier but had fewer thigh scratches at d 35 compared with the control groups. In addition, locomotion was negatively affected among the lesion-induction group, as they had a higher gait score at d 36 compared with the control group. We concluded that increased litter moisture content not only caused severe FPD but also reduced broiler performance and carcass yield and had a negative effect on other welfare aspects.     

Effects of Natustat supplementation on performance, feed efficiency and intestinal lesion scores in broiler chickens challenged with Eimeria acervulina, Eimeria maxima and Eimeria tenella

The effects of dietary supplementation of Natustat™, a propriety plant derived product (Alltech Inc., KY, USA) and Salinomycin, on performance, feed efficiency and intestinal lesion scores were observed during two Eimeria challenge trials in broiler chickens. In the first trial chickens were challenged with Eimeria sp. via infecting the litter with a known amount of Eimeria oocysts. In the second trial the source of the Eimeria challenge was the litter from the first trial and the same treatment groups were assigned to the same pens as in the initial trial.

Birds were placed 55 per pen with seven pens per treatment. Performance parameters were recorded on days 21 and 42 during both trials. Intestinal lesion scores were assessed on days 14 and 21 during Trial 1 and on day 21 during Trial 2. Average weight gain and feed conversion ratios were significantly improved in the Natustat™ and Salinomycin treatment groups when compared to the non-supplemented infected group. Furthermore, lesion scores were lower on all sampling days in the Natustat™ and Salinomycin groups when compared to the non-supplemented group. However, only lesions associated with Eimeria tenella were significantly lowered by Natustat™ and Salinomycin supplementation.

Natustat™ and Salinomycin were equivalent in alleviating the negative performance effects associated with coccidiosis challenge. In summary, Natustat™ has the potential to be used as a natural alternative to chemotherapeutic drugs for Eimeria control.     

Chopped palm leaves as an acceptable bedding material for broiler production

An experiment was conducted to examine the suitability of chopped palm leaves to utilize as a bedding material, compared to wood shavings or wheat straw, on growth performance, immune response, and air quality for broiler production. Three bedding materials were used: wood shavings, chopped palm leaves, and wheat straw. A total of 3,240 one-day-old broiler chicks (Ross 308) was randomly distributed into 3 litter groups (1,080 birds each). Each group had 6 replicate pens (180 birds/pen). All birds were kept under similar environmental conditions, except for bedding material. The obtained results revealed that the growth performance and total mortality rate were not significantly affected by bedding material type. However, using chopped palm leaves as bedding material significantly reduced (P < 0.05) ammonia emission compared to wood shavings and wheat straw (4.1, 7.3 and 8.4 ppm, respectively). A similar trend was observed for settled dust concentration (4.0, 10.3, and 5.9 g/m², respectively). Moreover, an improvement in cell-mediated immunity was observed in boilers kept on chopped palm leaves. Carcass characteristics were not significantly affected by bedding material. It was concluded that chopped palm leaves are a good alternative bedding material to wood shavings and wheat straw in commercial broiler production.     

Experimental reproduction of enterococcal spondylitis in male broiler breeder chickens

There has been a recent emergence of epidemic spinal infections with necrosis causing lameness and mortality in male broilers and broiler breeders. Mortality in affected flocks may be as high as 15%. The disease has been called enterococcal spondylitis (ES), based on the frequent isolation of Enterococcus cecorum from the lesions and necrosis and inflammation observed in the free thoracic vertebrae (FTV) of affected birds. Male broiler breeders in an experimental setting were challenged with pure E. cecorum isolates obtained from ES-affected commercial flocks. Challenge routes included oral gavage (10(8)), intravenous (i.v.; 10(3)), and air sac (AS; 10(3)). Half the study birds in each group were chemically immunosuppressed with dexamethasone. Spinal lesions were observed grossly in birds challenged intravenously (2.9%) and birds challenged orally (6.1%). Microscopic spinal lesions consistent with ES were more frequently identified compared with gross lesions in the orally challenged group (30.3%). Chemical immunosuppression with dexamethasone was not associated with a greater incidence of ES in this study. By recreating the disease experimentally, the study design reported here may help in the further development of an experimental challenge model for future studies on risk factors, prevention, and therapeutic intervention of ES.