J Zoons

Bacterial eggshell contamination in conventional cages, furnished cages and aviary housing systems for laying hens

1. The influence of housing system on the initial bacterial contamination of the eggshell was studied. Two long-term experiments were performed. 2. Bacterial eggshell contamination, as expressed by total count of aerobic and Gram-negative bacteria, was periodically analysed for eggs from a conventional cage, a furnished cage with nest boxes containing artificial turf or grids as nest-floor material and an aviary housing system. Results were log-transformed prior to statistical analyses. 3. For both experiments no systematic differences were found between the conventional cage and furnished cage. The type of nest-floor material in the nest boxes of the furnished cages also did not systematically influence the bacterial contamination. 4. A possible seasonal influence on contamination with a decrease in the winter period (up to > 0·5 log cfu/eggshell) of total count of aerobic and Gram-negative bacteria was observed in the first experiment. 5. The contamination with total aerobic flora was higher (more than 1·0 log) on eggs from the aviary housing system compared to the conventional and the furnished cage systems. For Gram-negative bacteria this was not the case. 6. During the entire period of both experiments, independent of housing system, shell contamination was not influenced by age of hens or period since placing the birds in the houses. 7. For the total count of aerobic bacteria a restricted positive correlation (r 2 = 0·66) was found between the concentration of total bacteria in the air of the poultry houses and initial shell contamination.

Design of laying nests in furnished cages: influence of nesting material, nest box position and seclusion

1. Preferences for three nesting materials and nest box positions were investigated simultaneously in two trials using a furnished cage: one with 18 individual laying hens and one with 18 groups of 5 hens. Following a habituation period in pre-test cages, every hen or group of hens was tested for 2 d: once without and once with plastic flaps at the entrance of the nest boxes. 2. Hens preferred peat and artificial turf to coated wire mesh for egg laying. 3. One nest box position was clearly preferred to both other nest boxes. The hens’ choice of nest box position was influenced by the pre-test cage in which they had been habituated. 4. The presence of plastic flaps at the entrance of the nest boxes had no influence on the proportion of eggs laid on the different nesting materials or on the proportion of floor eggs. 5. Individual and group testing resulted in the same overall results despite the presence of a distinct group effect.

Bacteriological contamination, dirt, and cracks of eggshells in furnished cages and noncage systems for laying hens: An international on-farm comparison

For laying hens, the effects of housing system on bacterial eggshell contamination and eggshell quality is almost exclusively studied in experimental hen houses. The aim of this study was to compare eggshell hygiene and quality under commercial conditions. Six flocks of laying hens in furnished cages and 7 flocks in noncage systems were visited when hens were about 60 wk of age. Farms from Belgium, the Netherlands, and Germany were included in the study. The following parameters were determined on eggs sampled at the egg belts: 1) bacterial eggshell contamination, as expressed by total count of aerobic bacteria and number of Enterobacteriaceae; 2) proportion of dirty eggs; and 3) proportion of cracked eggs and eggs with microcracks. Considerable within-flock differences were found in eggshell contamination with total count of aerobic bacteria, both for furnished cages (P < or = 0.001, range 4.24 to 5.22 log cfu/eggshell) and noncage systems (P < or = 0.001, range 4.35 to 5.51 log cfu/eggshell). On average, lower levels of contamination with total count of aerobic bacteria (4.75 vs. 4.98 log cfu/eggshell; P < or = 0.001) were found on eggshells from furnished cages compared with noncage systems. Concerning Enterobacteriaceae, no significant difference in average eggshell contamination between both systems could be shown. The total percentage of cracked eggs was higher (P < or = 0.01) in furnished cages (7.8%) compared with noncage systems (4.1%). This was, however, due to the high percentage of cracked eggs (24%) observed on one of the furnished cage farms. We conclude that bacteriological eggshell contamination and percentage of cracked eggs differed substantially between individual farms using the same housing system. This may also explain some discrepancies between the findings of the present study versus some findings of previous experimental studies or studies on a small number of farms. Although statistically significant, the average differences in bacteriological contamination of nest eggs between both housing systems have limited microbiological relevancy.

The transmission color value: A novel egg quality measure for recording shell color used for monitoring the stress and health status of a brown layer flock

Stress and diseases have the potential to influence the deposition of eggshell pigmentation during egg formation. Therefore, defining the shell color of eggs on a daily basis could be a representative method for monitoring stress or health status of a flock and maintaining good performance. A novel way of measuring eggshell color based on visible-near infrared transmission spectroscopy transmission spectra was defined: the transmission color value (TCV). The TCV was calculated as the ratio between the transmission at 643 nm (maximum absorbance of the pigmentation molecule protoporphyrin IX) and the transmission at 610 nm (a reference wavelength). Experiments were carried out to investigate the relevance of TCV for monitoring flock stress and health or even anticipating any factors unfavorable to performance. In 2 small experimental flocks, deliberate heat stress challenges were applied. A medium-scale experimental flock in an aviary was monitored on a daily basis during the whole productive period. From the deliberate heat stress challenges, it was seen that stress had a significant effect on eggshell pigmentation. This observation was confirmed in a daily monitored flock, in which, for example, an infectious bronchitis infection occurred. These stress situations were quickly reflected by an increased TCV value: more transmission due to less pigmentation and hence less absorbance at the pigmentation wavelength. Furthermore, for the observed problems in the daily monitoring, the TCV value signaled the problem earlier (4 d) than the average egg weight or even signaled when the other parameters did not signal anything. Measuring the TCV of all eggs produced on a daily basis provides relevant information on the stress or health status of a flock of brown layers. This could be used as an early detection of stress situations or emerging diseases, even before important quality and health damage can occur.

Mathematical-models in broiler raising

Among poultry scientists there is an increasing interest in model building because models are useful in the investigation of the economic consequences of management decisions and in identifying gap...

On-farm comparisons of different cleaning protocols in broiler houses

The present study evaluated the effectiveness of 4 cleaning protocols designed to reduce the bacteriological infection pressure on broiler farms and prevent food-borne zoonoses. Additionally, difficult to clean locations and possible sources of infection were identified. Cleaning and disinfection rounds were evaluated in 12 broiler houses on 5 farms through microbiological analyses and adenosine triphosphate hygiene monitoring. Samples were taken at 3 different times: before cleaning, after cleaning, and after disinfection. At each sampling time, swabs were taken from various locations for enumeration of the total aerobic flora and Enterococcus species pluralis ( SPP:). In addition, before cleaning and after disinfection, testing for Escherichia coli and Salmonella was carried out. Finally, adenosine triphosphate swabs and agar contact plates for total aerobic flora counts were taken after cleaning and disinfection, respectively. Total aerobic flora and Enterococcus spp. counts on the swab samples showed that cleaning protocols which were preceded by an overnight soaking with water caused a higher bacterial reduction compared to protocols without a preceding soaking step. Moreover, soaking of broiler houses leads to less water consumption and reduced working time during high pressure cleaning. No differences were found between protocols using cold or warm water during cleaning. Drinking cups, drain holes, and floor cracks were identified as critical locations for cleaning and disinfection in broiler houses.

Comparison of sampling procedures and microbiological and non-microbiological parameters to evaluate cleaning and disinfection in broiler houses

Cleaning and disinfection of the broiler stable environment is an essential part of farm hygiene management. Adequate cleaning and disinfection is essential for prevention and control of animal diseases and zoonoses. The goal of this study was to shed light on the dynamics of microbiological and non-microbiological parameters during the successive steps of cleaning and disinfection and to select the most suitable sampling methods and parameters to evaluate cleaning and disinfection in broiler houses. The effectiveness of cleaning and disinfection protocols was measured in six broiler houses on two farms through visual inspection, adenosine triphosphate hygiene monitoring and microbiological analyses. Samples were taken at three time points: 1) before cleaning, 2) after cleaning, and 3) after disinfection. Before cleaning and after disinfection, air samples were taken in addition to agar contact plates and swab samples taken from various sampling points for enumeration of total aerobic flora, Enterococcus spp., and Escherichia coli and the detection of E. coli and Salmonella. After cleaning, air samples, swab samples, and adenosine triphosphate swabs were taken and a visual score was also assigned for each sampling point. The mean total aerobic flora determined by swab samples decreased from 7.7±1.4 to 5.7±1.2 log CFU/625 cm2 after cleaning and to 4.2±1.6 log CFU/625 cm2 after disinfection. Agar contact plates were used as the standard for evaluating cleaning and disinfection, but in this study they were found to be less suitable than swabs for enumeration. In addition to measuring total aerobic flora, Enterococcus spp. seemed to be a better hygiene indicator to evaluate cleaning and disinfection protocols than E. coli. All stables were Salmonella negative, but the detection of its indicator organism E. coli provided additional information for evaluating cleaning and disinfection protocols. Adenosine triphosphate analyses gave additional information about the hygiene level of the different sampling points.

Gizzerosine-induced histopathological lesions in broiler chicks

1. The aim of this study was to investigate pathomorphological changes in broiler chicks fed with different doses of gizzerosine, a substance produced during the heat treatments of fish meal. 2. The experiment was carried out in Ross broiler chicks which were divided into three groups: group A received 100% of non-medicated commercial mash for broiler chicks. During an experimental 5-d period, 50% of commercial mash was replaced with unheated fish meal (0.65 ppm gizzerosine) in group B and in group C with heated fish meal (1.15 ppm gizzerosine). Fourteen chicks from each group were killed every day. Samples of gastrointestinal and lymphoid organs, lung, pancreas, liver, brain and kidney tissue were sampled for histopathological analysis. Organs were embedded in paraffin and stained with hematoxylin-eosin stain and using periodic acid-Schiff reagent (PAS) and Sudan III (frozen sections). 3. Necropsy did not reveal notable differences between treated groups. There were no significant histopathological changes in immunocompetent organs nor in the lungs, the pancreas, the kidney or the brain. Sharply demarcated multiple vacuoles were observed in the myocardium in group C toward the end of the experiment. In group C, the prevalent changes in the gizzard and the proventriculus were slight to severe cuticle erosions and oedema of the lamina propria with or without multiple vacuoles, respectively, towards the end of the experiment. The most prominent changes toward the end of the experiment were dispersed cell vacuolisation in duodenal, jejunual, ileal and caecal lamina propria in group C. 4. In conclusion, it should be emphasised that extra-gizzard gizzerosine-induced lesions are probably not mediated by H 2 -receptor stimulation, but could be a consequence of cellular hypoxia.

Identification and biocide susceptibility of dominant bacteria after cleaning and disinfection of broiler houses

&NA; Hygiene in animal production is key for both farm management and food safety. Cleaning and disinfection (C&D) of broiler houses is essential to manage farm hygiene. Still high levels of total aerobic flora after C&D in broiler houses are reported. However, little is known about the microbial composition after cleaning (AC) and after disinfection (AD). In addition, the question why some bacterial species/isolates are still present AD whereas others are killed remains. The study was carried out in 4 broiler houses. Sampling was performed AC and AD. The disinfectant was based on hydrogen peroxide and peracetic acid. Enumerations were carried out for total aerobic flora, Enterococcus spp. and Enterobacteriaceae. The dominant bacteria present was assessed by (GTG)5 analysis and 16S rRNA gene sequence analysis. Moreover, minimum bactericidal concentration (MBC) tests were carried out on 18 selected isolates belonging to the Enterobacteriaceae family and 10 Enterococcus faecium isolates. A wide variety of bacteria were detected AC and AD. In total, 363 and 255 isolates were identified AC and AD, respectively, resulting in a total of 109 identified species. The most dominant bacteria belonged to Brevibacterium, Brachybacterium, and Staphylococcus AC and Bacillus, Brevibacterium, and Staphylococcus AD. At both sampling moments, Enterococcus faecium was dominant among the Enterococcus spp. isolates. On the selective medium for Enterobacteriaceae, the genera Enterobacter and Pantoea and Aeromonas (non Enterobacteriaceae) were dominant AC while Escherichia, Lelliottia, and Pantoea were dominant AD. In addition, species pathogenic to poultry and humans were identified not only AC but also AD. MBC results showed no trend in selection of less susceptible isolates for the used disinfectant AD compared to AC. Finally, the recommended concentration of the disinfectant (i.e., 0.5% commercial solution of hydrogen peroxide and peracetic acid) seemed too low to kill Enterobacteriaceae.

Influence of whole wheat inclusion on optimal feed withdrawal duration

1. The objective of the present study was to examine whether the commonly applied duration of feed withdrawal (10 h) should be altered if broilers receive a commercial whole wheat (WW) diet instead of a completely pelleted (C) diet. 2. Inclusion of whole wheat in the diet did not affect weight gain, feed intake or feed conversion. 3. The effect of different feed withdrawal (FW) durations on body weight loss was similar for both diets. 4. Gall bladder content was not significantly greater after longer feed withdrawal periods, irrespective of diet composition. Birds given the WW diet had significantly greater gall bladder contents than birds receiving the C diet. 5. Both diets had similar effects on wet weight of the total gut contents, mean relative wet contents of each gut region and percentage water content of the gut contents. 6. These results indicate that a feed withdrawal period of 10 h is sufficient for broilers on the WW diet.