Salmonella colonization in young chickens given feed supplemented with the growth promoting antibiotic avilamycin

The feed given to young broiler chickens was contaminated artificially with Salmonella kedougou, a serotype associated with both subclinical infections in commercially reared chickens and food poisoning in humans. No evidence was obtained to suggest that the growth promoting antibiotic avilamycin, added to the feed at the rate of either 2.5 ppm or 10 ppm, had the undesirable side-effect of favouring the colonization of the intestinal tract of the birds with Salmonella kedougou when they were challenged with this organism in the feed.     

Some consequences of the ingestion by young and growing pigs of feed contaminated with ergot.

Growing pigs were fed freshly milled ergot sclerotia (Claviceps purpurea Fr (Tul)) from North American wheat containing 0-31 per cent of total alkaloids of which 30 per cent was ergotoxine, 30 per cent ergosine, 20 per cent ergotamine and 20 per cent other ergot alkaloids. Pigs were induced to ingest a diet heavily contaminated with ergot (10 per cent w/w). The presence of ergot reduced feed intake and growth of the pigs, but there was no evidence of peripheral necrosis, of internal or external haemorrhage, or of changes in haemotological characteristics. Balance experiments in which the diet was contaminated with 4 per cent (w/w) of ergot showed that 90 per cent of the alkaloids were absorbed by the pigs, but none could be detected in tissues or urine. The ingestion of ergot did not affect the digestibility of the diet, but the urinary excretion of nitrogen was increased and the retention of nitrogen reduced. The presence of ricinoleic acid was shown to be a useful diagnostic feature of ergot contamination of diets, digesta and faeces; it was not found in body tissues.     

Infection by Salmonella typhimurium, S. agona, S. enteritidis or S. infantis of chicks with caecal coccidiosis

Experimental infections of Salmonella typhimurium, S. agona, S. enteritidis or S. infantis were studied in chicks infected with Eimeria tenella. In all experiments, 4-d old birds were given 5 daily oral doses of approximately 10(4) salmonella organisms per bird. One day before this inoculation one group of birds received a single dose, in the range 1 X 10(4) to 4 X 10(4) sporulated oocysts of E. tenella per os whilst the other group was not inoculated and served as the control. Chicks were examined post morten 7, 10 or 14 d after receiving coccidia. With S. typhimurium infection, the number of salmonellas in the caeca of the E. tenella-infected birds was greater than in those infected only with salmonella. With S. agona and S. enteritidis, the counts of salmonella in the caeca and the numbers of birds positive for salmonella in the caeca and liver were greater in the E. tenella-infected birds. The rate of infection of S. infantis was not increased by caecal coccidiosis.     

Anticoccidial efficacy of diclazuril in pheasants

Diclazuril, a new anticoccidial drug, was tested in young pheasants artificially infected with the three most common pathogenic species of Eimeria, E colchici, E duodenalis and E phasiani. In two replicate experiments each with 40 birds the mortalities in the infected controls were 50 and 25 per cent. Diclazuril was administered in the feed at dose levels of 1, 2 and 4 ppm from the day before the inoculation of coccidia until the end of the test on day 6 after infection. The 1 ppm dose failed to inhibit the development of the parasite completely, as was shown by a reduction of the weight gain of the birds and the output of a small number of oocysts. Diclazuril at 2 or 4 ppm adequately controlled the infection, with weight gains similar to those of the uninfected controls. At all dose levels, mortality, intestinal lesions and diarrhoea were prevented.     

Growth response of chicks following addition to the diet of various sources of nitrogen

Two experiments involving a total of 320 day‐old Chunky P male chicks were conducted. In the first experiment chicks were divided into 6 groups and given one of the following diets ad libitum for 6 weeks: A, with determined essential amino acids at minimal required levels; B, with published values for essential amino acids at minimal required levels; C, conventional broiler diet; D, A+1.5 per cent diammonium phosphate (DAP); E, A+3.0 per cent DAP; and F, A+4/4 per cent DAP. Adding 1.5 per cent DAP gave a significant increase in live‐weight at 4 weeks, but adding 3.0 or 4.4 per cent DAP depressed weight significantly at 4 or 6 weeks. Weights of birds receiving diet B were significantly lower than those of birds receiving diets A or C.

In the second experiment chicks were divided into 5 groups and given one of the following diets ad libitum for 4 weeks: GA (similar to A) or GA supplemented with the equivalent of 2 per cent crude protein in several forms. In HM the form was herring meal and in GG, DS and DP it was glycine+glutamic acid, diammonium sulphate and DAP, respectively. Body weights of birds receiving HM were greater (though not significantly) than those receiving GA but were significantly poorer than those fed GG, DS or DP.     

Comparison of two shampoos as sole treatment for canine bacterial overgrowth syndrome

Two antibacterial shampoos for the treatment of canine bacterial overgrowth syndrome (BOGS) were compared in a prospective controlled clinical trial. Forty dogs with clinical signs (pruritus, erythema and excoriations without pustules and/or collarettes) and cytological findings compatible with bacterial overgrowth were treated twice weekly with 3 per cent chlorhexidine shampoo (3 per cent CHX) or 2.5 per cent benzoyl peroxide shampoo (2.5 per cent BPO) and evaluated every two weeks for up to six weeks until cytological cure. Pruritus, erythema, greasy seborrhoea, malodour, excoriations, secondary hair loss, lichenification, hyperpigmentation and lesion extent were each scored on a 0 to 3 severity scale and combined to calculate an aggregate score. Among the 34 dogs with good compliance to treatment, reduction of cocci counts of at least 90 per cent was recorded in 11 of 18 dogs after 3 per cent CHX and nine of 16 dogs after 2.5 per cent BPO, with no significant difference between the two products (P=0.98). Lesion score was significantly reduced in both groups (63.48 (34.45)) per cent with 3 per cent CHX v 54.45 (33.61) per cent with 2.5 per cent BPO, P=0.36) and time to cytological cure was not significantly different between groups (P=0.13), at the end of the treatment. In the present study, 3 per cent CHX and 2.5 per cent BPO were similarly effective in the treatment of canine BOGS.     

Efficacy of danofloxacin in the therapy of experimental mycoplasmosis in chicks.

Specific pathogen free day-old chicks were inoculated with a virulent strain of Mycoplasma gallisepticum. Birds received either danofloxacin (50 ppm), tylosin (500 ppm) or no medication in the drinking water from 24 hours after infection for three days. The effects of medication on mortality, weight gain, serology, lesions and reisolation of M gallisepticum 21 days following infection were studied. Treatment with danofloxacin and tylosin significantly decreased mortality and increased weight gain compared with infected unmedicated birds. Twenty-one days after infection, M gallisepticum was isolated from 96 per cent of unmedicated birds compared with only 6 per cent of danofloxacin-treated and 40 per cent of tylosin-treated birds, and the percentage showing positive serological tests was reduced from 100 per cent of unmedicated birds to 0 per cent of danofloxacin-treated and 29 per cent of tylosin-treated birds. In both cases, the proportion of positive birds from the danofloxacin-treated group was significantly lower than that from the tylosin-treated group. The occurrence of air sac lesions was also significantly lower in danofloxacin-treated than in tylosin-treated birds.     

Evaluation of the influence of supplementing the diet with mannose or palm kernel meal on salmonella colonisation in poultry

1. The dietary inclusion of 15 and 25 g/kg mannose was associated with a reduction in the numbers of Salmonella enteritidis (PT4) in the caecal contents of chicks challenged by the food. The same benefit was not recorded for S. infantis, possibly because this strain, unlike S. enteritidis PT4, lacked mannose‐sensitive fimbriae.

2. The addition of 25 g/kg palm kernel meal (PKM), but not 20 g/kg desiccated coconut, to the food reduced the degree of salmonella colonisation in the intestinal tract of broiler chicks given diets contaminated with S. kedougou or S. enteritidis from the day of their arrival from the hatchery.

3. The beneficial effect of PKM was also demonstrated at an inclusion rate of 5 g/kg and was similar for preparations with a particle size of either < 150 μm or < 300 μm.

4. Day‐old birds challenged orally with S. enteritidis and given food supplemented with 25 g/kg PKM, became clear of infection by 3 weeks of age while birds given unsupplemented food remained infected.

5. These preliminary results suggest that the inclusion of PKM, which contains inter alia, oligosaccharides containing mannose, in the diet of chicks may reduce the extent to which the intestine is contaminated with salmonellas.     

Serological examination and egg production of progeny of fowl experimentally infected with egg drop syndrome 1976 virus

Following EDS'76 virus (BC14 virus) infection of breeder chickens by the conjunctival route, vertical transmission occurred in the first week after infection. In the progeny which had been infected with EDS'76 virus by the vertical route, increasing haemagglutination inhibiting (HI) titres to BC14 virus and increasing numbers of birds with HI titres were observed from 3 weeks to 15 weeks of age. Sixty-one per cent of the hens and 77 per cent of the cocks had 2 log HI BC14 virus titres exceeding 4 at an age of 15 weeks. Some birds which han been serologically negative throughout the rearing period, seroconverted between 25 and 28 weeks of age. This phenomenon occurred in hens as well as in cocks. Simulation of stress twice during the laying period by injection of corticosteroid hormone did not increase the number of birds serologically positive to EDS'76 virus. EDS'76 was observed in the group of hens that was vertically infected, since egg production was significantly depressed between 28 and 34 weeks of age. Probably this was mainly the results of a production drop in the hens showing serconversion at 27 or 28 weeks of age. In this group of fowl vertically infected with EDs'76 virus, serologically positive birds appeared to be protected for the greater part to BC14 virus challenge at 50 weeks of age, while negative birds seemed to be fully susceptible. Chicks hatched from eggs collected in the third and fourth week after infection of the dams had maternal antibodies. Fertility and hatchability of apparently normally shelled eggs seemed not to be affected after BC14 virus infection of the dams. Intensive contact with contaminated faeces is probably an indispensable condition for lateral transmission of the virus.     

Development and application of an ELISA for detecting antibodies to Salmonella enteritidis in chicken flocks.

Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG antibody to Salmonella enteritidis in poultry flocks. A lipopolysaccharide (LPS) and heat-extracted (HE) antigen for use in the ELISA were evaluated together with the rapid slide test (RST), microagglutination test (MT) and the microantiglobulin (MAG) test. In experimentally infected specific pathogen free chickens, good correlation was seen between all tests although, generally, the MT and MAG detected antibody earlier and titres peaked earlier than the ELISAs. The LPS antigen detected antibody earlier than the HE antigen but the latter gave higher titres in the later stages of infection. Cross reactions were seen between S enteritidis and S typhimurium in the ELISAs although homologous reactions were always much higher. Antisera to S montevideo or S senftenberg gave weak positive reactions in both S enteritidis ELISAs. Serological and bacteriological examinations of representative samples from two commercial chicken flocks were carried out. In flock A the HE-ELISA and MAG test detected antibody in nearly all birds. The LPS-ELISA detected antibody in over 60 per cent of birds, while the MT and RST detected few seropositive birds. The whole blood test using the stained S pullorum antigen on the farm detected antibody in just under 25 per cent of the birds. S enteritidis was isolated from the organs of 25 per cent of the birds. All birds in flock B were seronegative by all tests; no salmonellae were isolated from the organs of these birds.     

The efficacy of lactic acid bacteria Pediococcus acidilactici, lactose and formic acid as dietary supplements for turkeys

A feeding trial was performed on 1400 Big-6 turkey toms divided into experimental groups subject to the use of dietary supplements. The ain of this study was to evaluate the efficacy of the probiotic supplement Bactocell, containing lactic acid bacteria Pediococcus acidilactici, and lactose, administered to turkeys separately or in combination, as well as a formic acid supplement. The addition of the probiotic under test (lactic acid bacteria Pediococcus acidilactici) to diets for turkeys contributed to higher daily gains and lower feed consumption per kg weigh gain only during the first 12 weeks of their life. Diet supplementation with lactic acid bacteria and lactose reduced mortality rates. A slaughter value analysis revealed only a slightly (by approximately 1%) higher content of breast muscle and a lower content of thigh muscle in birds fed diets supplemented with lactic acid bacteria. Turkeys receiving lactic acid bacteria or lactose and a combination of both these supplements were characterized by a higher fat content of meat and slightly lower pH values, whereas meat from turkeys fed lactose-supplemented diets was darker in color. The addition of formic acid Acidum formicum to diets for turkeys contributed only to lower mortality rates.     

Role of Coccidia in the occurrence of necrotic enteritis of chickens

Clostridium perfringens type A, Eimeria acervulina, and Eimeria necatrix were used to produce necrotic enteritis in chickens. The disease was produced in all groups of birds that received feed contaminated with C. perfringens. Mortality due to necrotic enteritis was highest (53%) in birds infected with E. acervulina before infection with clostridia. There was a significant difference in mortality rates between birds infected with E. acervulina and birds infected with E. necatrix before infection with C. perfringens. Mortality rates also differed significantly between the group infected with E. necatrix and the group that received only feed contaminated with C. perfringens. It was concluded that under field conditions, coccidia can play a significant role in the occurrence of necrotic enteritis when a sufficient number of toxigenic strain of C. perfringens type A is present. The pathological changes induced by clostridia and coccidia are described.     

Serological examination and egg production of progeny of fowl experimentally infected with Egg Drop Syndrome 1976 virus

Summary

Following EDS'76 virus (BC14 virus) infection of breeder chickens by the conjunctival route, vertical transmission occurred in the first week after infection. In the progeny which had been infected with EDS'76 virus by the vertical route, increasing haemagglutination inhibiting (HI) litres to BC14 virus and increasing numbers of birds with HI litres were observed from 3 weeks to 15 weeks of age. Sixty‐one per cent of the hens and 77 per cent of the cocks had ²log HI BC14 virus litres exceeding 4 at an age of 15 weeks.

Some birds which had been serologically negative throughout the rearing period, seroconverted between 25 and 28 weeks of age. This phenomenon occurred in hens as well as in cocks. Simulation of stress twice during the laying period by injection of corticosteroid hormone did not increase the number of birds serologically positive to EDS'76 virus.

EDS'76 was observed in the group of hens that was vertically infected, since egg production was significantly depressed between 28 and 34 weeks of age. Probably this was mainly the result of a production drop in the hens showing seroconversion at 27 or 28 weeks of age.

In the group of fowl vertically infected with EDS'76 virus, serologically positive birds appeared to be protected for the greater part to BC14 virus challenge at 50 weeks of age, while negative birds seemed to be fully susceptible. Chicks hatched from eggs collected in the third and fourth week after infection of the dams had maternal antibodies. Fertility and hatchability of apparently normally shelled eggs seemed not to be affected after BC14 virus infection of the dams. Intensive contact with contaminated faeces is probably an indispensable condition for lateral transmission of the virus.     

The effect of diet and copper supplementation on chick growth

Two experiments are described in which various diets were fed to broiler chicks, with or without a supplement of 0.1 per cent CuSO 4.5 H₂O supplying 250 mg/kg added Cu. When the basal diet was composed mainly of wheat and fish meal with added tallow, growth responses to copper measured at 6 weeks of age were 7.6 per cent in the first experiment (highly significant) and 2.8 per cent in the second experiment (0.1 > P > 0.05). When the basal diet was composed mainly of maize and soya‐bean meal there was no response to added copper in the first experiment and a significant depression in growth in the second experiment. A basal diet containing 25 per cent of dried whey gave very poor growth (about 60 per cent of normal) but showed a large response to the addition of Cu. Responses to added Cu in all diets were generally larger in the faster growing males than in the female chicks.

Where positive growth responses to copper were obtained, food consumption was usually higher, but efficiency of food utilisation was better in the chicks given the copper‐supplemented diets.

The average concentrations of Cu found in the livers of birds with or without copper supplements were 4.41 and 4.10 mg/kg of fresh liver respectively in the first experiment and 6.88 and 4.56 mg/kg of fresh liver in the second experiment. The difference in the second experiment was highly significant.     

Effect of acidified feed on the prevalence of Salmonella in market-age pigs

Two trials were carried out to determine the effect of feed acidification upon Salmonella carriage in market-age pigs. In the first trial, the administration for the last 14 weeks of the fattening period of a commercial pelleted feed added with 0.6% lactic acid plus 0.6% formic acid (Lac-Formic-1.2) was compared to an unacidified standard diet (STD). A second experiment was carried out in two herds of growing pigs (Herd I, 3000 pigs; Herd II, 900 pigs) in which three different diets were assayed during the last 8-9 weeks of the fattening period: a diet containing 0.8% formic acid (Formic-0.8), a diet containing 0.4% lactic acid plus 0.4% formic acid (Lac-Formic-0.8) and a STD. In the first experiment, serological evolution of the infection was examined by ELISA and microbiological cultures (rectal samples and mesenteric lymph nodes) were also done. Feed intake by pen and the individual weight of the animals were also measured. In the second trial, blood, rectal samples and mesenteric lymph nodes were collected at slaughter in both herds (30 pigs per experimental group). In the first experiment, the acidified diet (Lac-Formic-1.2) reduced Salmonella carriers in mesenteric lymph nodes (Fisher's exact P < 0.01). In the second trial, Lac-Formic-0.8 diet significantly reduced Salmonella seroprevalence compared to the STD (P = 0.001) in both herds. Also Lac-Formic-0.8 and Formic-0.8 diets in Herd II showed a lower faecal excretion and Salmonella carriage in mesenteric lymph nodes than the STD (P < 0.05). Our results suggest that the administration of a combination of lactic and formic acids at the levels used in this study could be used to reduce Salmonella prevalence in finishing pigs.     

The effect of organic acids on the control of porcine post-weaning diarrhoea

Post-weaning diarrhoea syndrome (PWDS) of piglets is caused mainly by Enterotoxigenic Escherichia coli (ETEC) strains. Six organic acids were tested for their efficacy in the control of PWDS, using a total of 384 weaned piglets, in eight groups, during a 28-day period. One group (negative control) was offered a diet free of antimicrobials, one group (positive control) was offered the same diet medicated with 44 p.p.m. of lincomycin and 44 p.p.m. spectinomycin (Lincospectin 22 premix, Upjohn), and six groups were offered feed supplemented with either 1.0 per cent propionic acid, 1.6 per cent lactic acid, 1.2 per cent formic acid, 1.2 per cent malic acid, 1.5 per cent citric acid or 1.5 per cent fumaric acid. Groups were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. All groups supplemented with organic acids had reduced incidence and severity of diarrhoea, and performed significantly better than the negative control group (P<0.05). At the end of the trial, ETEC strains were detected in the control group not receiving antibiotics but not in the treated group. Organic acids and especially lactic acid are a useful tool in controlling PWDS.     

Salmonella infections in swine herds--epidemiology and importance for human diseases]

Based on pertinent literature and research work performed by the authors, a report is presented on the presence of salmonellas in swine herds and the importance of these organisms as agents of disease in swine and source of infection for human salmonellosis. The share among human cases of salmonellosis which are caused by salmonellas originating from swine is estimated at ca. 20%. It has to be assumed that a very large proportion of swine herds is contaminated by Salmonella. Salmonellas may be introduced through infected pigs (parent animals, pigs from other herds added to the herd) or carriers among other animal species (e.g. rodent pests, birds) as well as by feeding stuffs with primary or secondary contamination. So far, the individual importance of the various routes cannot be reliably assessed. It appears that the level of Salmonella prevalence within a herd essentially depends on the hygienic conditions, the mode of keeping and the management of the animals. Serological examinations of meat juice permit conclusions as to the level of Salmonella contamination in slaughtered pigs. The results can thus be used for programmes to reduce the introduction of salmonellas into the food chain.     

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

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 X 10(6) 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.     

The effect of 3‐nitro‐4‐hydroxyphenylarsonic acid (3‐nitro‐hoechst) on egg production and food conversion of laying hens and residue analyses of muscle,organs and eggs

White Leghorn pullets were divided into two groups, each comprising 5 pens with 15 or 16 birds per pen. The experiment began when the birds were 20 weeks old and finished on the 500th day of life. The control group received a normal ration containing 16 per cent protein whilst the experimental group received the same ration supplemented with 50 p.p.m. 3‐nitro‐4‐hydroxyphenylarsonic acid (3‐nitro‐hoechst).

Food consumption and egg weight were similar in both groups but the treated group laid 4 per cent more eggs. Although this was not significant, the treated group showed an overall improvement in the efficiency of food utilisation of 2.5 per cent.

For a period of 6 months the arsenic content of 10 eggs was determined weekly and after this time at fortnightly intervals. At the end of the experiment 10 birds of each group were killed and the arsenic contents of the heart, liver, kidneys, tibia, pectoral muscle and feathers were determined. The arsenic contents of the eggs, heart, kidneys, muscle and bone of the experimental birds were not significantly different from the controls. However, the liver of the birds fed the supplement contained twice and the feathers fifteen times as much arsenic as the control birds.     

Treatment of broiler litter with organic acids

Experiments for treatment of contaminated broiler litter with citric, tartaric and salicylic acids were performed. At days 2 and 6 after the treatment, pH values (using a pH-meter), the ammonia concentrations (titration with 0.1 N HCl) and the microbial cells counts were determined in both experimental and control specimens of litter. The cost of acidification of litter was also determined. Our studies showed that the treatment of the contaminated litter with 5 per cent citric acid, 4 per cent tartaric acid and 1.5 per cent salicylic acid created an acid medium with pH under 5.0 and thus reduced the microbial counts to 2.2 x 10(3)colony forming units per gram manure litter. The treatment reduced the content of ammonia in the litter and in the air under the hygienic limits, i.e. 25-50 ppm. The cost of acidification of litter with these organic acids amounted to 0.1 $ per bird and 1.5 $ per 15 birds on one square metre in a growth period of 50 days.