The objective of the two studies was to determine the influence of RepaXol, a blend of double coated essential oils (EO), AciXol, an encapsulated blend of organic and inorganic acids along with EO (ACI) or bacitracin methylene disalicylate (BMD), an antibiotic, on the performance of coccidial vaccinated broiler chickens reared to 42 days of age. Both studies had a similar experimental design. The second study used built up litter with a higher level of coccidial oocysts and Clostridium. The stocking density was 0.07 sq. meters per male bird. All chicks were spray vaccinated with a commercial coccidial vaccine. A randomized block design with 8 replications was used. The test treatments were nonmedicated, EO 50 ppm (study 2) and 100 ppm, ACI 500 ppm (study 1), or BMD 55 ppm. Results showed a significant improvement in Day 42 performance, both feed conversion and weight gain with EO 50 and 100 ppm, ACI 500 ppm, and BMD 55 ppm compared to the nonmedicated controls. The feed conversion and weight gain for EO and BMD were not significantly different in either study. No matter the background challenge level, EO, ACI, and BMD improved performance of coccidial vaccinated broiler chickens.
The objective of this study was to compare the effects of inorganic and proteinate Zn in chickens challenged with coccidia and Clostridium perfringens. A 3 × 2 factorial design was used, with 3 dietary formulations (0 or 90 mg/kg supplemental Zn from ZnSO4 or Zn proteinate, with or without challenge). On day 14, challenged birds were orally gavaged with approx. 5,000 Eimeria maxima sporulated oocysts, and on day 19 to 21 with C. perfringens (108 CFU/D). Productive performance was assessed at day 21 and 28. At 21 D, necrotic enteritis (NE) lesion severity, intestinal permeability, gene expression, and ileal and cecal microbiota were evaluated. An interaction of Zn source by challenge was observed for lesion score and mortality, wherein Zn supplementation decreased the degree of NE lesions (P = 0.02) and mortality due to NE (P = 0.008). In the jejunum, an interaction of Zn source by challenge was observed for the expression of IL-8 (P = 0.001) and INF-γ (P = 0.03), wherein the NE challenge upregulated their expression, but not in the Zn proteinate supplemented birds. Zn proteinate supplementation downregulated iNOS vs. ZnSO4 supplemented birds (P = 0.0003), and supplemental Zn downregulated TLR-2 (P = 0.05) and ZnT5 (P = 0.04), regardless of the source. In the ileal microbiota, Zn proteinate supplementation decreased the frequency of Lactobacillus (P = 0.01), and the challenge increased Enterobacteriaceae (P = 0.01). Dietary Zn decreased NE lesion severity and mortality due to NE; Zn proteinate led to lower expression of IL-8 and INF-γ in challenged birds which may be an indicative of a lessened inflammatory response.
Two studies examined toxicity and the development of acquired coccidial immunity when using anticoccidials. The studies examined two ionophorus anticoccidials, monensin and lasalocid and two chemicals, halofuginone and amprolium. In the toxicity study, 16 week old tom turkeys that had never been exposed to anticoccidials were fed the test anticoccidials at the recommended or twice the recommended use levels. The ionophore salinomycin, typically fed to chickens, was also tested at 66 ppm. Salinomycin was found to be toxic, producing greater than 50% mortality and a 45% suppression in weight gain compared to non-medicated controls. No mortality was produced with any of the other products. At twice the recommended level of the ionophores monensin and lasalocid, there was a significant (P < .05) suppression in percent weight gain compared to non-medicated controls. Immunity in the context of this research is measured in protection from coccidial challenge. This study used an immunizing dose of mixed Eimeria species given to turkeys at 10 days of age. The effect of the test anticoccidials on acquisition of coccidial immunity was determined by challenge inoculation at 10 weeks of age, 1 day after all medications were removed. All anticoccidials allowed some immunity development as indicated by significantly (P < .05) higher weight gains, less coccidial lesions, and fewer oocyst shed compared to the non-medicated non-immunized challenged controls. Significant lower weight gains and higher oocyst shedding occurred with the turkeys fed halofuginone (3 ppm) for the 10 week period than with the turkeys fed with the other anticoccidials, indicating limited oocyst cycling due to stronger coccidial control.
The effect of an organic acids (OA) and medium-chain fatty acids (MCFA) containing product was tested on the course of artificial Necrotic Enteritis infection in broiler chickens at 2 and 5 kg/ton. Three control groups were used: 1. a non-infected non-medicated group; 2.an infected non-medicated group and 3. an infected medicated group (50 g/ton BMD). Two kg/ton of the OA/MCFA product significantly reduced the incidence of intestinal NE lesions by 22% as compared to infected, non-medicated control group. Weight gain (0-28 days) was improved by 29% and Feed conversion ratio (0-28 days) by 8%; total NE mortality was reduced by 43%. A dosage of 5 kg/ton of OA/MCFA product did not further improve parameters. Also BMD significantly improved performance and NE lesions. It is concluded that the tested OA/MCFA product shows mild anti-Clostridium effects in vivo and fits well in a total approach to control NE; the recommended dosage is 2 kg/ton. Introduction Necrotic enteritis (NE) in broiler chickens is caused by Clostridium perfringens. This disease has a large negative impact on the health of broilers and therefore on the profitability of commercial broiler operations. After the ban on antimicrobial growth promoters (AMGP), it is expected that incidence of NE will increase. Organic acids (OA) have been used for decades due to its preservative (flora modulating) effects in feed and subsequently in the first parts of the gastro-intestinal tract. Medium-chain fatty acids (MCFA) recently have caught scientific interest due to its antibacterial effects (Stratford and Anslow, 1996; Van Immerseel et al., 2004). In this research a product combining organic acids (formic, acetic, propionic, and sorbic acid) and medium-chain fatty acids (caprylic, and capric acid) was tested. In vitro research had already indicated a strong anti-Clostridium effect of this product (MIC value of 0.15%; Corujo Fernandez, 2004, Nutreco internal report). A next step was to test the effect of this product in vivo. We used an experimental model with a two-step infection, first with Eimeria challenge and successively with Clostridium perfringens. The animal performance and intestinal NE lesion score were measured. The hypothesis was that the experimental product would improve these parameters compared to an infected control group without additives; a medicated group with 50 g/ton of growth promoter Bacitracin Methylene Disalicylate (BMD) was also tested. Materials and Methods The experiment was carried out at the Southern Poultry Research Centre, Athens, USA. Five experimental treatments were tested: 1 Selacid Green Growth Poultry MP, Selko BV, Tilburg, The Netherlands.
Extensive usage and the limited number of approved poultry anticoccidial drugs has led to some degree of resistance being developed to all drugs. Three independent battery trials were conducted to evaluate the anticoccidial drug sensitivity (AST) of species/strains of Eimeria within three commercial coccidia vaccines. The vaccines used for these studies were Immucox 3® (broiler vaccine) (IM3), Immucox 5® (broiler breeder vaccine) (IM5), and Immucox T® (turkey vaccine) (IMT). Each trial used a randomized block design with six replications. Each cage contained eight male Cobb 500 broilers (IM3 and IM5) or eight male Hy-Line turkeys (IMT). At 12 days of age (D0), birds were group weighed, allocated to treatment cages, and issued weighed treatment feeds. Birds and remaining feed were weighed on D8 (20 days of age) (IM3 and IM5) or D9 (21 days of age (IMT)). Anticoccidial drugs were blended at commercial use levels. The treatments were as follows. IM3: 1) Nonmedicated nonchallenged (NMNC); 2) Nonmedicated challenged (NMC); challenged and medicated with 3) robenidine 33 parts per million (ppm); 4) decoquinate 30 ppm; 5) clopidal 125 ppm; 6) zoalene 125 ppm; 7) diclazuril 1 ppm; 8) amprolium 125 ppm; 9) salinomycin 66 ppm; 10) narasin 39.6 ppm + nicarbazin 39.6 ppm; and 11) narasin 74.25 ppm. IM5 used the same IM3 treatments 1–11 plus 12) nicarbazin. IMT: 1) NMNC; 2) NMC; 3) lasalocid 79.2 ppm; 4) monensin 66 ppm; 5) amprolium 125 ppm; 6) zoalene 125 ppm; and 7) nicarbazin 125 ppm. The challenge for each vaccine was 100 times the commercial recommended dose given orally on D2 (14 days of age). For trials IM3 and IM5, on D8 (6 days postchallenge) all chickens were coccidia lesion scored. IMT oocysts per gram (D7–9) and dropping scores (D8) were determined instead of lesion scores. For IM3 and IM5 vaccines, the results showed that all strains were sensitive to all anticoccidial drugs. For turkey IMT vaccine, the results showed that all strains were highly sensitive to all anticoccidial drugs. This information can serve as a foundation for the use of these coccidia vaccines in the restoration of coccidia sensitivity in the field.
A series of studies were conducted to assess the drug sensitivity of 26 coccidial field isolates to the anticoccidial effects of nicarbazin (NIC) and narasin + NIC (NAR + NIC). Isolates were collected from typical broiler farms in the United States from 2003 to 2006, propagated once in the absence of anticoccidial medication, and then used to inoculate broilers that were fed nonmedicated rations or those containing NIC 125 ppm or NAR + NIC 80 ppm. Results of these sensitivity trials indicated that 81% of these coccidial isolates were sensitive to the effects of NIC, but only 22% of these coccidia were controlled by NAR + NIC. Studies conducted to evaluate performance responses to these drugs demonstrated that birds fed NIC gained more weight and utilized feed more efficiently than those receiving NAR + NIC. The results of 2 floor pen tests, conducted to confirm the results of the above sensitivity trials, demonstrated that NIC provided a greater level of protection from coccidiosis than NAR + NIC. Lower lesion scores and improved performance were recorded for birds receiving NIC compared with NAR + NIC. Results of these studies revealed that changes in the susceptibility of Eimeria spp. to the activity of NAR + NIC are evident. These changes appear to be associated with the reduction in ionophore sensitivity that has been documented in most areas of the world.
Two dietary sources of zinc (ZnSO4 or organic Zn) were tested in chickens challenged with coccidiosis (Co) or coccidiosis plus Clostridium perfringens (CoCPF). On day 14, the chickens were orally gavaged with ∼5,000 Eimeria maxima sporulated oocysts. On day 19, 20, and 21 chickens challenged with C. perfringens were given a broth culture containing 108 cfu of this bacterium. Productive performance parameters were determined at d 14, 21, and 28. On day 21, necrotic enteritis (NE) lesions were scored, and intestinal permeability was evaluated. Jejunum and cecal tonsils were collected for morphology and gene expression analysis. On day 21, organic Zn improved BW gain by 18.6% (P = 0.07), and FCR by 12% (P = 0.09) in CoCPF challenged chickens vs. birds fed ZnSO4. From 1 to 28, organic Zn increased BW gain (P = 0.02), and improved FCR (P = 0.03) vs. birds fed ZnSO4. At 21 d, NE lesions were only observed in CoCPF birds (P < 0.001), and mortality due to NE was only observed when CoCPF birds were fed ZnSO4 (P = 0.001). Organic Zn fed birds had increased villus height in the jejunum (P = 0.005) and decreased intestinal permeability (P = 0.01) vs. ZnSO4. In the jejunum, organic Zn fed birds showed a downregulation of expression of IL-8 (P = 0.02), and upregulation of IL-10 (P = 0.05) in CoCPF birds vs. ZnSO4- CoCPF birds. As main effect, birds supplemented with organic Zn had higher mRNA expression of TLR-2 (P = 0.02) and IgA (P = 0.01). In the cecal tonsils, organic Zn fed birds showed upregulation of iNOS (P = 0.008) in CoCPF birds vs. ZnSO4-CoCPF birds. Organic Zn supplementation reduced intestinal permeability and attenuated intestinal inflammation of broilers co-challenged with coccidia and C. perfringens.
The levels of luteinizing hormone (LH) and androgens were measured in sterile avian hybrids. Guinea fowl-chicken and peafowl-guinea fowl hybrids were bled before and after injection with LH- releasing hormone (LHRH). The preinjection LH levels for the guinea fowl-chicken hybrids were below or at the very lower limit of the assay sensitivity and the peafowl-guinea fowl hybrids averaged 1.3 ng/ml. Within 10 min after LHRH injection, LH had increased dramatically in both hybrids and then began to slowly decline. Androgen levels in the guinea fowl-chicken hybrids increased from 16.2 pg/ml to 95.2 pg/ml and continued to increase, reaching 287 pg/ml at the last bleeding 60 min after injection.
