Protection of chicks against salmonella infection induced by spray application of intestinal microflora in the hatchery

Summary

The efficacy of spray application of intestinal microflora of the adult bird in protection of broilers against salmonella infections was studied in 3 experiments under laboratory and field conditions.

In chicks treated soon after hatching (in the hatchers at approximately 30 per cent hatch or in the chick delivery boxes in the hatchery) with crop‐caecum homogenate or a mixture of aerobically and strict anaerobically cultured intestinal flora, very good results were achieved.

A very obvious protective effect against a high infection dose (3 × 10 c.f.u. S. infantis bacteria per chick) and complete protection against natural infection with different salmonella types was induced.

A significant improvement of growth rate was observed in broilers treated by spray in the hatchery and reared for 7 weeks under field conditions in an environment heavily contaminated with different salmonella types.     

Reduction of salmonella infection of broilers by spray application of intestinal microflora: a longitudinal study

The Nurmi concept for diminishing salmonella infection of poultry by application of gastrointestinal microflora from adult birds into newly hatched chicks was tested in a field study in which 8 million broilers were involved. Half of the 284 flocks was treated in the hatchery by spray application of an undefined microflora propagated in SPF chicks. A significant reduction in salmonella-contaminated flocks, as well as in the number of infected broilers in these flocks was demonstrated. No undesirable side effects were detected. It was concluded that hygienic improvements in transportation and slaughtering of broilers are needed in order to maintain the reduced salmonella contamination rate.     

Protection of chicks against Salmonella infantis infection induced by strict anaerobically cultured intestinal microflora

Summary

In two experiments newly hatched broilers were orally inoculated either with intestinal microfloras cultured under different conditions or with a suspension of intestinal homogenate and challenged with high doses (3 x 10⁵ c.f.u. per chick) of Salmonella infantis organisms.

Inocula were prepared from intestinal material of mature SPF WL hens under aerobic or strictly anaerobic conditions (< 5 ppm oxygen), and protected against atmospheric oxygen during storage. A very significant reduction of the number q/Salmonella infantis bacteria in caecal content was achieved one and two weeks after challenge in those groups of chicks which were inoculated with anaerobically cultured flora or with intestinal homogenate. In order to induce protection, obligate anaerobes had to be accompanied by facultative anaerobes. Amprolium or Monensin dit not interfere with protection. Protection induced by intestinal microflora depends on anaerobiosis during preparation, culturing, storage, and application of the protective bacteria. Starvation on the first day of life appeared to have a negative effect on protection.     

Influence of temperature, social, and dietary stress on development and stability of protective microflora in chickens against S. typhimurium

In the day-old chick, physiological stress in the form of high or low temperatures or feed and water deprivation either interfered with colonization or altered the protection provided by normal intestinal microflora against subsequent challenge with Salmonella typhimurium. The response was more obvious after individual exposure of chicks to salmonella than after exposure to infected seeders. Physiological and dietary stress at 2 weeks of age did not appreciably alter the S. typhimurium excretion pattern in treated chicks. The protective microflora appears to be quite stable under these stress conditions.     

A questionnaire-based,retrospective field study of persistence of Salmonella Enteritidis and Salmonella Typhimurium in Danish broiler houses

A questionnaire-based, retrospective field study was conducted in 78 Danish broiler houses (analytical units) on 42 farms. In spring 1997, all these broiler houses had been infected with Salmonella Enteritidis, phage type 8, and/or Salmonella Typhimurium, definitive-type 66, by day-old chicks delivered from the same hatchery. Because these two salmonella types had not been detected in the Danish broiler sector before and the broiler houses were infected in a period of low salmonella prevalence, the study could focus on farm-related factors, without being distorted by other salmonella infections.

The same person visited all 78 broiler houses, and farm-related factors were listed both from personal observations and by interrogating the person in charge of attending to the broilers. Additional factors (noted at the visits) were recorded in a later telephone interview. Altogether, 187 variables were analyzed.

Broiler houses were divided into single-infection houses (which had one or both of the salmonella types in only one crop), and multiple-infection houses (where infection occurred in multiple crops). This was done both generally and separately for each of the salmonella types.

Factors associated with house status—but that were beyond the control of the farmer—were the salmonella type and the percentage of salmonella positive samples in the first crop. Factors which could be controlled by the farmer and which were associated with reduced prevalence of multiple-infection houses included antiseptic soap and water for washing hands in the anteroom, hygiene barriers when removing dead broilers, gravel alongside the broiler house, systematic checks of indoor rodent-bait depots, and combined surface and pulse-fogging disinfection.     

Comparison of the effect of live Newcastle disease vaccine Clone 30 in broilers administered at day 1 or at day 7 and the effect of H120 vaccination at 17 days of age: a field experiment

To analyse the results of a vaccination on the first day of age against Newcastle disease (ND) and on the 17th day of age against Infectious Bronchitis (IB) resp. with spray vaccines with Clone 30 and H120 vaccine. These vaccinations are compared in field circumstances with other vaccination methods. A serological examination and challenge test were used to be informed about the response and protection. From the present study the following conclusions can be drawn: Clear indications are obtained that following a spray vaccination against ND with Clone 30 vaccine of one-day-old broilers which possessed maternal antibodies, birds received a moderately good protection against ND, in spite of very low levels of HI antibodies. A spray vaccination against IB with H120 vaccine of broilers at 17 days of age gave some protection from two weeks after vaccination, however making a good conclusion about the protection is impossible and further investigation is required.     

Vaccination of one-day-old broiler chicks against infectious coryza

In order to evaluate the protection conferred by an experimental inactivated vaccine against infectious coryza, three challenge trials were undertaken using 112 1-day-old broilers. The vaccine "Hepa Inmuno NC" included bacterial antigens of Avibacterium paragallinarum (serogroups A, B, variant B, and C) as well as antigens of Newcastle virus and hepatitis virus. Fifty-six broiler chicks were vaccinated at the first day of life at the hatchery while another 56 chicks were left unvaccinated. Three infection trials were conducted simultaneously using each of the three serogroups A, B, or C of Av. paragallinarum. In each trial, 17 vaccinated and 17 unvaccinated broilers were used. Challenge was performed at day 31 of life by injection, into the left infraorbital sinus, of approximately 1 x 10(5) colony forming units of the corresponding Av. paragallinarum strain. Clinical signs were recorded on day 2 postchallenge. All broilers were euthanatized and both infraorbital sinuses were bacteriologically examined for the presence of Av. paragallinarum on day 5 postchallenge. In comparison with the unvaccinated broilers, the vaccine significantly reduced the number of broilers with clinical signs after challenge with serogroup B, and significantly fewer vaccinated broilers were positive for the presence of Av. paragallinarum after challenge with serogroup C. On the other hand, no significant protection was observed when broilers were challenged with Av. paragallinarum from serogroup A. Despite the high infection rates in vaccinated chicks after an experimental infection with Av. paragallinarum, it was possible to reduce colonization of Av. paragallinarum (serogroup B) and clinical signs (serogroup C) in broiler chicks by vaccination at the first day of life. Further cross-protection trials should be done, including other Av. paragallinarum strains in the vaccine, especially those from serogroup A.     

Further studies on competitive exclusion for controlling Salmonellae in chickens

A native intestinal microflora of chickens which is protective against salmonella readily transferred to penmates and apparently to birds in adjacent pens. The microflora not only minimized infection resulting from exposure following colonization of the gut with microflora, but significantly abbreviated the period of infection when introduced after a salmonella infection was established in chicks. A microflora with undiminished protective activity, sensitive to only a few commonly used antibacterials, was established in a SPF-Cofal/Marek-negative population. Intestinal microflora from mourning doves was at least partially effective in protecting chicks against a naladixic-acid-resistant strain of Salmonella infantis. In limited tests with 2 of 3 sources of protective microflora, the growth rate of chicks in the absence of salmonellae was significantly improved. A hypothesis involving specificity of attachment between the glycocalyces of the protective microflora and of the intestinal mucosa is offered as the likely mechanism of protection.     

Preliminary field test of lyophilised contagious caprine pleuropneumonia vaccine

Fifty goats were immunised in the field against contagious caprine pleuropneumonia (CCPP) using a single dose (0.15 mg) of lyophilised, saponin killed Mycoplasma strain F38. Two months after vaccination, these goats together with 50 unimmunised control goats were challenged by contact with goats experimentally infected with CCPP. Twelve vaccinates and 14 controls died of diarrhoea due to salmonella infection during the first two weeks after challenge. The remaining immunised goats (38) with the exception of two goats which had elevated temperatures were protected from CCPP. Of the remaining 36 control goats, 30 contracted CCPP at a mean of 39 (+/- 14.3 SD) days after challenge and 27 of them died. These results show that the lyophilised killed F38 vaccine conferred 100 per cent protection against mortality and 95 per cent protection against clinical disease caused by Mycoplasma species strain F38.     

Risk Factors Associated with Salmonella Status of Broiler Flocks Delivered to Grow‐Out Farms

In a prospective field observational study in the southeastern USA, we sampled gastrointestinal (GI) tracts from chicks of 65 broiler flocks delivered to conventional grow‐out farms for rearing. The flocks were hatched at seven broiler hatcheries. The mean within‐flock prevalence of Salmonella‐positive samples was 6.5% and ranged from 0% to 86.7%. Of the 65 flocks studied, 25 (38.5%) had at least one Salmonella‐positive sample. Accounting for confounding variability among the hatcheries and broiler companies, we tested whether the probability of detecting Salmonella in GI tracts of the chicks delivered was associated with certain characteristics of parent breeder flocks; hatchery production volume; hatchery ventilation system; hatchery egg‐room conditions; egg incubation, candling, hatching, eggshell and bird separation, and bird‐processing procedures; management of hatchery‐to‐farm transportation; day of week of hatch; weather conditions during transportation; or season of the hatch. Two risk factor models were adopted. The first model indicated that a greater number of parent flocks, manual separation of eggshell and bird, and a greater amount of fluff and feces on tray liners used during hatchery‐to‐farm transportation at delivery were associated with increased probability of detecting Salmonella in chick GI tracts, whereas a greater number of birds in the delivery vehicle was associated with decreased probability. The second model indicated that broiler flocks hatched on Tuesdays versus either Mondays or Thursdays (with no hatches on Wednesdays, Fridays or week‐ends), increased average hatchability of the eggs from the parent flocks, and greater amounts of fluff and feces on the transport tray liners at delivery were all associated with increased probability of detecting Salmonella in chick GI tracts. The results of this study suggest potential management decisions to lessen Salmonella contamination of broilers supplied by commercial hatcheries and areas for further research.     

Laboratory evaluation of Newcastle disease vaccination programs for broiler chickens

Experiments were conducted to examine the efficacy of various commercial vaccination programs for the prevention of Newcastle disease (ND) in broilers. In all, chicks were from breeders vaccinated against ND via drinking water at 75-day intervals. Vaccination was by company personnel on company premises. In Expt. 1, the initial ND vaccination programs tested were vaccination at 1 day by coarse spray with the Spra-Vac machine or by tracheal instillation with the Beak-o-Vac machine, and vaccination at 7 days via drinking water. In Expts. 2-4, birds initially vaccinated via one of the three previously mentioned methods (Spra-Vac in Expt. 2, Beak-o-Vac in Expt. 3, and drinking water in Expt. 4) were revaccinated against ND by either drinking water or coarse spray with one of two commercial portable machines (ULVA Fan or Spray Master). Serologic and challenge data in Expt. 1 indicated that although broilers vaccinated by any of the three initial routes failed to produce measurable antibody to NDV, all methods resulted in protection against NDV challenge at 35 and 49 days. However, resistance to challenge with virulent ND was greatest in birds initially vaccinated by coarse spray with the Spra-Vac machine. Results in Expts. 2-4 indicated that NDV hemagglutination-inhibition titers were highest and resistance to challenge greatest in birds initially vaccinated at day 1 by coarse spray (Spra-Vac) and then revaccinated at 14 days by coarse spray. There were no differences, however, between the portable coarse spray machines in efficacy in reimmunizing broilers against NDV.     

Studies on feasibility of producing Salmonella-free turkeys

The feasibility of producing salmonella-free turkeys was investigated over a 5-year period. In Phase 1, a hatchery-breeder flock operation was monitored extensively for 4 years. Hatching eggs from a primary breeder over this period (1978-81) resulted in salmonella-free day-old poults from which 7500 hens and 600 tons were selected for breeders each of the 4 years. Approximately 2.5 million poults were produced over the 4 years. Salmonella arizonae was isolated from the hatchery debris over a 2-week period in 1980. The pelleted feed contained no animal protein products except fish solubles. A sample of feed from each delivery was cultured with no salmonella isolations. Environmental samples of dust and litter remained negative for salmonella. Phase 2 involved monitoring seven grow-out flocks initiated with salmonella-free poults with extra precautions directed at the feed and environment. The intestinal tracts of five of seven flocks at the time of marketing were negative for salmonella. Phase 3 involved a primary breeder-hatchery that had a 10-year history of S. sandiego infection in its breeder flocks and poults. A vaccination program using an autogenous oil-adjuvant bacterin supplementing other sanitation and management efforts resulted in elimination of S. sandiego. Because the breeder went out of business, it was not possible to determine if the freedom from salmonella could be sustained over a period of years.     

Influence of Water Provision to Chicks Before Placement and Effects on Performance and Incidence of Unabsorbed Yolk Sacs

A study was conducted to determine the effect of water provision to chicks before placement on performance and the incidence of unabsorbed yolk sacs. To accomplish this, a device was used that was designed to deliver water to chicks in chick baskets during holding at the hatchery and transportation to the growout house. Commercial chicks were obtained from the hatchery and held for either 24 or 48 h with or without access to water before placement. Chicks were then distributed into floor pens with ad libitum access to feed and water. At 6 wk of age, broilers were processed, and intestines were evaluated for presence or absence of an unabsorbed yolk sac and intestinal breaking strength. Body weight at placement was 2 to 6 g greater for chicks given access to water; however, this difference was not observed at any other time during the growout. Water provision during holding had no affect on feed consumption, mortality, or the birds’ ability to completely absorb the yolk sac during the 6 wk growout. Incidence of unabsorbed yolk sacs in 6 wk old birds ranged from 15 to 28%. Moreover, presence or absence of an unabsorbed yolk sac had no effect on intestinal breaking strength. Data from the present study demonstrates that providing chicks with water before placement does not influence performance, intestinal breaking strength, or the incidence of unabsorbed yolk sacs.     

Control of salmonella infections in broiler chickens by the acid treatment of their feed

In three experiments a solution of formic acid (Bioadd) was added to feed 'naturally' contaminated with salmonellas. In two of them no salmonella infections were demonstrated in broiler chickens given feed containing 0.6 per cent (w/w) of the formic acid solution for seven weeks and in the third the infection rate was reduced considerably. In four other experiments the feed was contaminated artificially with between 1 and 47 Salmonella kedougou/g and a second product (BPO12), consisting of a mixture of formic acid and propionic acid, was evaluated. When it was added at 0.5 to 0.68 per cent (w/w) only one of 30 groups of 10 to 12 birds became infected with S kedougou by two weeks of age, compared with 22 of 27 control groups. The treatment of the feed with BPO12 one week before the addition of the salmonellas prevented the establishment of infection in chicks given the treated feed, indicating that acid treatment will provide protection against subsequent recontamination of the feed with the organisms. The isolation rate of S kedougou from artificially contaminated feed treated with BPO12 was reduced only slightly but the feed was apparently 'safe' for the birds which consumed it.     

In vivo biologic effects of recombinant-turkey interferon-gamma in neonatal leghorn chicks: protection against Salmonella enteritidis organ invasion.

Interferon-gamma (IFNgamma) has been demonstrated to have potent stimulatory effects on parameters of cell-mediated immunity in chickens (11). Protection of neonatal leghorn chickens against infection by invasive salmonellae has been associated with enhanced cell-mediated indices of immunity (5). The present investigation evaluated the effect of recombinant-turkey (rt) IFN-gamma on protection of neonatal leghorn chicks from Salmonella enteritidis (SE) organ invasion after experimental challenge in three experiments. In Expt. 1, intraperitoneal (i.p.) administration of 25 microg rtIFNgamma per chick 30 min prior to per os SE challenge resulted in a 35% reduction (P < 0.01) in SE organ invasion when compared with control (vehicle injected) chicks 24 hr post-SE challenge. However, i.p. administration of 2.5 microg rtIFNy per chick was not efficacious in reducing SE organ invasion. In Expt. 2 and Expt. 3, i.p. administration of 13.75 microg rtIFNgamma per chick 30 min prior to per os SE challenge resulted in significant reductions of 38.4% (P < 0.025) and 31.58% (P < 0.01), respectively, in SE organ invasion as compared with control chicks 24 hr post-SE challenge. Administration of 2.5 or 25 microg rtIFNgamma per chick i.p. had no effect on SE organ invasion in either Expt. 2 or Expt. 3 24 hr post-SE challenge. Additionally, i.p. administration of rtIFNgamma 30 min prior to SE challenge in Expt. 2 and Expt. 3 was not associated with protection against SE organ invasion when organ culture was performed 72 hr postchallenge. Further, the oral administration of 25 microg rtIFNgamma per chick was not efficacious in conferring protection against SE organ invasion at 24 or 72 hr postchallenge when this route of administration was evaluated in Expt. 2. Similarly, the subcutaneous administration of a potential repository injection of 13.75 or 25 microg rtIFNgamma per chick did not protect chicks against SE organ invasion when evaluated 72 hr postchallenge. These data indicate a potential acute immunostimulatory activity of rtIFNgamma in chickens experimentally challenged with SE. Further, these experiments, although preliminary, are suggestive of the potential involvement of IFNgamma in cell-mediated or innate mechanisms of protective immunity against salmonellosis in chickens.     

A Survey of Small-scale Broiler Production Systems in Botswana

Aspects of husbandry, productivity parameters, diseases, marketing and farmer attitudes in small-scale broiler farms in Botswana were studied using a questionnaire-based survey. The number of broilers per production cycle in small-scale operations ranged from 100 to 2000, with an average of 640. On average, small-scale producers had 4-5 production cycles per annum with an interval of 2-3 weeks between batches. The average marketing age was 48.3 days at a live weight of 1.79 kg and a carcase weight of 1.42 kg. The average feed conversion ratio was estimated to be 2.72 (kg feed/kg live weight) and the average mortality was 9.15%. Overall, the performance indices of broilers under small-scale farm conditions were much poorer than those obtained elsewhere under improved management conditions, but these lower performance levels are suggestive of the potential that exists for further improvement. The survey also identified several areas of concern that constrain the realization of the full potential of this sector. Factors contributing to the poor performance under small-scale farm conditions are complex, but feed supply and quality, chick quality and farmer training appear to be areas for immediate improvement.     

Effective treatment and control of biting lice, Felicola subrostratus (Nitzsch in Burmeister, 1838), on cats using fipronil formulations

The efficacy of 0.25% fipronil spray (Frontline Spray, Merial), 10% fipronil spot-on (Frontline Spot-on for Cats, Merial) and 10% fipronil/12% (S)-methoprene (Frontline Plus for Cats, Merial) against the biting louse Felicola subrostratus on cats was assessed and confirmed under laboratory conditions. A field study evaluated the efficacy of a single topical application of Frontline Spray, and spot-on against the parasite on cats. In the laboratory studies, animals were allocated based on pre-treatment louse counts to the treatment groups: (1) untreated control and (2) 10% fipronil spot-on in the exploratory study or (1) untreated control, (2) 0.25% fipronil spray, at 6 ml/kg; (3) 10% fipronil spot-on as per label and (4) 10% fipronil/12% (S)-methoprene as per label in the confirmation study. Cats in treatment groups 2-4 were treated twice topically on Days 0 and 28. No live F. subrostratus were found on cats treated with fipronil formulations at any post-treatment examination. The difference from controls was significant (P < 0.01) for each product at each examination. Based on whole body counts at Day 42, the efficacy of each product was determined to be 100%. In the field study, cats were allocated in strict order of presentation. Cats were randomly allocated to one of the three treatment groups: (1) propoxur collar (Bolfo, Bayer); (2) 0.25% fipronil spray, at 6 ml/kg and (3) 10% fipronil spot-on as per label. Cats were treated once topically on Day 0. Louse counts of cats treated with fipronil formulations were not different than those of cats receiving the propoxur collar. The efficacy was determined to be > 98% on Day 2 and 100% on Days 28 and 42 in all treatment groups. The results of these studies demonstrate that fipronil in topical formulations is effective for treatment and control of biting lice (F. subrostratus) infestations on cats.     

Effect of dietary beta1-4 mannobiose in the prevention of Salmonella enteritidis infection in broilers

1. This study investigated the effects of beta1-4 Mannobiose (MNB)-supplemented feeds on the kinetics of Salmonella enterica serovar Enteritidis (SE) in broilers and the ensuing histopathological changes. D-Mannose (MAN) was used for comparison. The diets supplemented with MNB or MAN were fed during the first two weeks after hatching to investigate any protection against SE infection in growing birds and any immunomodulatory functions in the gut. 2. MNB-supplementation reduced SE organ colonisation, caecal carriage and faecal shedding in a time-dependent manner. The high concentrations and persistency of the SE-specific IgA response in those birds given rations supplemented with MNB or MAN were associated with a decline in SE shedding and caecal carriage in the later stages of infection. MNB was more effective against SE infection than MAN. 3. Histological examination of the caecal wall and caecal tonsils at 23 d post-infection indicated a lesser degree of intestinal pathology. An increased number of intra-epithelial mononuclear cells (mature lymphocytes and macrophages) in the lining epithelium of birds fed on the diet supplemented with MNB was accompanied by an increased number of lamina propria cells. 4. The present study indicates that feeding a diet supplemented with MNB during the first two weeks after hatching reduced susceptibility to SE infection. Supplementing the diet with MNB or MAN increased IgA production and improved SE clearance by acting as immunomodulatory agents that prevented intestinal pathology. Feeding a MNB-supplemented diet to broilers could be used as an alternative to antibiotics, because it has no adverse effects on mortality or weight gain.     

肉仔鸡饲粮中蛋氨酸和半胱氨酸与赖氨酸适宜比例的研究

本试验旨在研究饲粮中不同(蛋氨酸+半胱氨酸)/赖氨酸[( Met+ Cys)/Lys]比例对内仔鸡生长性能和经济效益的影响,探讨肉仔鸡饲粮中适宜的( Met+Cys)/Lys比例.选取1日龄罗斯308商品肉仔鸡3 600只,随机分为4个饲粮处理,( Met+ Cys)/Lys比例分别为0.64、0.68、0.72和0....