Effects of strain and stocking density on leg health, activity, and use of enrichments in conventional broiler chicken production.

Conventional broiler production needs to evolve towards more animal-friendly production systems in order to meet increasing consumer concerns regarding animal welfare. Genetics and stocking density are 2 of the most promising leads to make this change possible. In this study, 6 strains with different growth rates (42-61 g/d) were reared at contrasting densities: 37 kg/m² (HD) and 29 kg/m² (LD). At the same body weight of 1.80-1.95 kg, we evaluated how growth rate and stocking density influenced broiler behaviors (general activity, interactions with enrichments), broiler health (mortality, leg problems, cleanliness and plumage growth) and litter quality. Density did not affect body weight, mortality or behaviors. For all strains, LD was associated with a lower prevalence of hock burns, a better gait score, and improved litter quality and broiler cleanliness. For the 3 strains most affected by pododermatitis, a lower prevalence was observed in LD than in HD pens. Fewer birds were inactive and more birds were standing and interacting with the enrichments (as proposed in the experiment) as soon as the growth rate was lower than that of the control strain (Ross 308). Others welfare indicators such as gait score, plumage growth improved as well. Litter humidity decreased with growth rate, contributing to better leg conditions and cleaner breasts. The prevalence of hock burns and certain behaviors (i.e., the proportion of birds grooming or walking/running) were not affected by growth rate. The proportion of birds foraging was higher at a lower growth rate. These results suggest that reducing growth rate as a preliminary measure, and reducing density as a supplementary one, would improve conventional broiler welfare.

Feather pecking in laying hens housed in free-range or furnished-cage systems on French farms.

1. Beak trimming is currently used in France to avoid the negative consequences of severe feather pecking (SFP). However, this practice is controversial in terms of animal welfare, and forbidden in some European countries.2. This study aimed to assess the prevalence of SFP in French laying hen farms, to describe how farmers manage this behavioural disorder and to better understand the risk factors involved.3. A study was carried out from April 2015 to June 2016. Visits were paid to 79 flocks kept in furnished cages (FC) and 80 flocks in a free-range (FR) system. All the hens had trimmed beaks and were genotypically brown. The information collected included feather cover, skin damage, beak condition, farm and poultry house characteristics, livestock performance and management.4. The prevalence of SFP in FC flocks was estimated at 32.9% (IC = 95%, [22.5; 43.3]) and the prevalence of cannibalism as 2.5% (IC = 95%, [0.7; 8.8]) at 70 weeks of age. The prevalence of SFP in FR flocks was estimated to be 23.8% (IC = 95%, [14.5; 31.1]) and the prevalence of cannibalism was 8.8% (IC = 95%, [4.3; 17.0]) at 61 weeks of age.5. In FC flocks, SFP was associated with the combination of genotype, type and length of perches, cage area per hen, type of lighting, number of hens per cage and farm location. In FR flocks, feather cover was associated with use of the outdoor run, lighting programme, genotype, farm location and date of house construction.

Effect of a photoperiodic green light programme during incubation on embryo development and hatch process.

This study was conducted to evaluate the effect of a 12-h light, 12-h dark (12L : 12D) photoperiod of green light during day 1 to day 18 of incubation time, on embryo growth, hormone concentration and the hatch process. In the test group, monochromatic light was provided by a total of 204 green light-emitting diodes (522 nm) mounted in a frame which was placed above the top tray of eggs to give even spread of illumination. No light-dark cycle was used in the control group. Four batches of eggs (n=300/group per batch) from fertile Ross 308 broiler breeders were used in this experiment. The beak length and crown-rump length of embryos incubated under green light were significantly longer than that of control embryos at day 10 and day 12, respectively (P<0.01). Furthermore, green light-exposed embryos had a longer third toe length compared with control embryos at day 10, day 14 and day 17 (P=0.02). At group level (n=4 batches), light stimulation had no effect on chick weight and quality at take-off, the initiation of hatch and hatch window. However, the individual hatching time of the light exposure focal chicks (n=33) was 3.4 h earlier (P=0.49) than the control focal chicks (n=36) probably due to the change in melatonin rhythm of the light group. The results of this study indicate that green light accelerates embryo development and alters hatch-related hormones (thyroid and corticosterone), which may result in earlier hatching.

An insight into the heat and mass transfer mechanisms of eggshells hatching broiler chicks and its effects to the hatcher environment.

Thermodynamic study of incubated eggs is an important component in the optimisation of incubation processes. However, research on the interaction of heat and moisture transfer mechanisms in eggs is rather limited and does not focus on the hatching stage of incubation. During hatch, both the recently hatched chick and the broken eggshell add extra heat and moisture contents to the hatcher environment. In this study, we have proposed a novel way to estimate thermodynamically the amount of water evaporated from a broken eggshell during hatch. The hypothesis of this study considers that previously reported drops in eggshell temperature during hatching of chicks is the result remaining water content evaporating from the eggshell, released on the inner membrane by the recently hatched wet chick, just before hatch. To reproduce this process, water was sprayed on eggshells to mimic the water-fluid from the wet body of a chick. For each sample of eggshell, the shell geometry and weight, surface area and eggshell temperature were measured. Water evaporation losses and convection coefficient were calculated using a novel model approach considering the simultaneous heat and mass transfer profiles in an eggshell. The calculated average convective coefficient was 23.9 ± 7.5 W/m(2) °C, similar to previously reported coefficients in literature as a function of 0.5-1m/s air speed range. Comparison between measured and calculated values for the water evaporation showed 68% probability accuracy, associated to the use of an experimentally derived single heat transfer coefficient. The results support our proposed modelling approach of heat and mass transfer mechanisms. Furthermore, by estimating the amount of evaporated water in an eggshell post-hatch, air humidity levels inside the hatcher can be optimised to ensure wet chicks dry properly while not dehydrating early hatching chicks.

Physiological status of broiler chicks at pulling time and the relationship to duration of holding period.

Newly hatched chicks may be held longer than 48 h and experience long periods of fasting in commercial hatcheries. Limited information is known about the physiological status of chicks in such situations, due to the difficulty of precisely recording time of hatch. This study investigated the effect of the time from hatch to pulling (holding period) on physiological measures/parameters in 109 broiler chicks. Fertile Ross 308 eggs were incubated in a custom built small-scale incubator. The individual hatching time of each focal chick was determined using eggshell temperature monitoring. At 'pulling' (512 h of incubation time), the quality of focal chicks was assessed using the chick scoring method and physiological parameters were measured including BW, organ (heart, liver and stomach) weights, blood values and plasma corticosterone level. The time from hatch to pulling varied from 7.58 to 44.97 h. Egg weight at setting was significantly correlated with chick BW and weight of organs at pulling, but had no effect on chick quality, blood values and plasma corticosterone. Relative BW at pulling was negatively associated with the duration of holding period (P=0.002). However, there was a positive correlation between relative stomach weight and the duration of the holding period (P<0.001). As the holding period duration increased, there was a trend that blood partial pressure of oxygen, haematocrit and haemoglobin also increased, and blood partial pressure of carbon dioxide, total carbon dioxide and bicarbonate decreased (P<0.05). A wide range of plasma corticosterone was observed from chicks that had experienced different durations of holding period. We conclude that shortening the hatch window and minimising the number of chicks that experience a long holding period before pulling may improve chick quality and physiological status, which may be due to unfavourable environmental conditions that include feed and water deprivation.

Effect of species-specific sound stimulation on the development and hatching of broiler chicks.

1. Previous research has reported that chicken embryos develop a functionary auditory system during incubation and that prenatal sound may play an important role in embryo development and alter the hatch time. In this study the effects of prenatal auditory stimulation on hatch process, hatch performance, the development of embryo and blood parameters were investigated. 2. Four batches of Ross 308 broiler breeder eggs were incubated either in control or in sound-stimulated groups. The sound-stimulated embryos were exposed to a discontinuous sound of species-specific calls by means of a speaker at 72 dB for 16 h a day: maternal calls from d 10 to d 19 of incubation time and embryo/chick calls from d 19 until hatching. The species-specific sound was excluded from the control group. 3. The onset of hatch was delayed in the sound-stimulated group compared to the controls. This was also supported by comparison of the exact hatching time of individual focal chicks within the two groups. However, the sound-stimulated embryos had a lower hatchability than the control group, mainly due to significantly increased numbers of late deaths. 4. The embryos exhibited a similar growth pattern between the sound-stimulated group and the control group. Although sound exposure decreased body weight at d 16, no consistent effect of sound on body weight at incubation stage was observed. Species-specific sound stimulation also had no impact on chick quality, blood values and plasma corticosterone concentrations during hatch.

Effect of substrate provision on performance and behaviour of laying hens in the pecking and scratching area of furnished cages.

1. An experiment was set up to study the effects of substrate provision on performance and behaviour in the pecking and scratching area (PSA) of non-beak-trimmed hens housed in large furnished cages (60 hens/cage). 2. Three layer hybrids (two brown and one white, ISA-Hendrix Genetics, France) and two substrate conditions (with or without wheat bran automatically distributed on the PSA) were compared in a 3 × 2 experimental design with 12 cages per treatment. 3. Substrate distribution improved laying rate with no impact on the frequency of dirty or cracked eggs. 4. Substrate distribution improved the viability and body integrity of hens, which were not beak-trimmed. 5. Distribution of substrate tended to increase the number of hens in the PSA and enhanced their pecking and scratching behaviours but had a negative impact on the number of dust bath bouts per cage and encouraged dust bathing on the wire floor close to the feeder. 6. The white hens laid more eggs in the nest than the brown birds and used the PSA more for pecking, scratching and dust bathing at the end of the day than the brown hens, underlining the necessity to adapt cage furnishing and rearing management to specific behaviours of each layer genotype.

Effect of transportation duration of 1-day-old chicks on postplacement production performances and pododermatitis of broilers up to slaughter age.

This experiment studied the effect of transportation duration of 1-d-old chicks on dehydration, mortality, production performance, and pododermatitis during the growout period. Eggs from the same breeder flock (Ross PM3) were collected at 35, 45, and 56 wk of age, for 3 successive identical experiments. In each experiment, newly hatched chicks received 1 of 3 transportation duration treatments from the hatchery before placement in the on-site rearing facility: no transportation corresponding to direct placement in less than 5 min (T00), or 4 (T04) or 10 h (T10) of transportation. The chicks were housed in 35-m(2) pens (650 birds each) and reared until 35 d old. Hematocrit and chick BW were measured on sample chicks before and after transportation. During the growout period, bird weight, feed uptake, and feed conversion ratio were measured weekly until slaughter. Transportation duration affected BW; T00 groups had a significantly higher BW than T04 and T10 transported birds but this effect lasted only until d 21. No clear effect on hematocrit, feed uptake, feed conversion ratio, or mortality was observed for birds transported up to 10 h. The decrease in weight in T10 birds was associated with less severe pododermatitis. Increasing age of the breeder flock was correlated with reduced egg fertility and hatchability, and also with higher quality and BW of hatched chicks. Chicks from older breeders also exhibited reduced mortality during the growout period.

Plumage condition, body weight, mortality, and zootechnical performances: the effects of linings and litter provision in furnished cages for laying hens.

This experiment was designed to determine the effect of litter provision and lining in nests and pecking and scratching areas on health and zootechnical performances. Research was carried out in furnished cages, each housing 60 beak-trimmed ISA Brown hens. Four different treatments were compared in a factorial arrangement, including 2 different nest linings (artificial turf versus plastic mesh), either used alone or combined with the use of litter (wheat bran) spread over the rubber mat in the pecking and scratching area (PSA). An additional treatment using artificial turf mat in the PSA and nests (as commonly used in commercial flocks) was used to compare the effect of PSA lining in the other treatments. Zootechnical performances (laying rate, egg weight, and feed intake) were unaffected by PSA lining or by nest lining. The use of artificial turf mats in the PSA resulted in less feather loss than rubber mats, especially on breast and cloaca/vent areas. No consequences were observed on BW or mortality. However, the use of plastic mesh in nests was seen to increase mortality in comparison with artificial turf mats, without affecting plumage condition and BW. Although wheat bran provision did not influence feed intake and laying rate, litter provision did result in slightly higher mean egg weight. Moreover, BW tended to be lower when litter was distributed in cages, and neck and breast plumage condition improved. The distribution of litter was not seen to have any effect on mortality. The provision of litter and the lining of the PSA and nests to improve the welfare of caged laying hens have an effect on mortality, plumage quality, and some zootechnical performances. These results show the importance of choosing the most suitable linings and litter to obtain the best possible compromise between the ethological needs of laying hens, zootechnical performance, and animal health.

Cage hygiene, laying location, and egg quality: the effects of linings and litter provision in furnished cages for laying hens.

This study investigates the influence of litter provision and linings used for nests and pecking and scratching areas on cage hygiene, laying location, and egg quality. Research was carried out in furnished cages, each housing 60 beak-trimmed ISA Brown hens. Four different treatments were compared in a factorial arrangement, including 2 different nest linings (artificial turf vs. plastic mesh), either used alone or combined with the use of litter (wheat bran) spread over the rubber mat in the pecking and scratching area (PSA). An additional treatment, using artificial turf mat in the PSA and nests (as commonly used in commercial flocks), was used to compare the effect of PSA lining in the other treatments. We observed laying location, the number of dirty and broken eggs, the microbiological contamination of eggshells according to laying location, and general cage hygiene. The use of nests for laying decreased when they were lined with plastic mesh. Eggs laid outside the nest were of lower quality than those laid inside it, and this was particularly true for eggs laid in the PSA. Although hygiene was low on artificial turf mats, eggs laid on PSA covered with a rubber mat were dirtier and had a higher count of mesophilic bacteria on the eggshell than those laid on PSA covered with an artificial turf mat. Rubber mats in PSA were rapidly destroyed and proved to be unsuitable. The provision of litter had no effect on cage hygiene but substantially increased wear on mats. This study shows nest lining and litter provision methods to be key factors that need to be taken into account to encourage the use of nest boxes for laying, and hence, to ensure good egg quality. Further research into new linings for PSA is needed for the future improvement of egg-laying conditions.

Furnished cages for laying hens: study of the effects of group size and litter provision on laying location, zootechnical performance and egg quality.

The furnished cage is a new housing system for layers. A current trend in furnished cage design is to increase group size and replace the litter box with a mat provided with litter. An experiment was set up to determine the effects of group size and litter provision on laying performance and egg quality of beak-trimmed ISA Brown hens housed in large furnished cages with more than 12 hens. Six treatments, each of 18 furnished cages (768 cm(2)/hen including nest and litter area) were compared in a 3 × 2 experimental trial: three group sizes (S20 (20 hens per cage), S40 (40) and S60 (60)), with or without feed as litter distributed on the mat of the litter area. The provision of facilities per hen was equal in all treatments. Mortality, laying rate, mean egg weight, feed intake and feed conversion ratio were unaffected by group size over the 53-week laying period, and performance exceeded the ISA production standards. The overall percentage of eggs laid in the nest exceeded 95% except that it was slightly lower in group S20 (92.0% ± 6.4% v. S40: 96.0% ± 3.3% and S60: 96.2% ± 2.7%) leading to a higher proportion of dirty eggs (S20: 1.6% ± 2.2%, S40: 1.4% ± 1.5%, S60: 1.0% ± 1.0%). At 66 to 70 weeks, eggs laid outside the nest had a slightly higher count of mesophilic bacteria on the eggshell (5.0 log CFU/egg ± 0.4) than those laid in the nest (4.8 log CFU/egg ± 0.5) but no difference in contamination was observed between group sizes. Litter provision had no effect on mortality, egg weight or egg quality traits except for a higher proportion of broken eggs in cages with litter (5.3% ± 6.2% v. 4.6% ± 5.7%). Providing hens with feed for litter was associated with a higher laying rate (97.3% ± 3.2% v. 94.8% ± 4.4% at 23 weeks) and an apparent improvement in feed efficiency at the beginning of the laying period (feed conversion ratio based on feed consumption at the trough: 2.18 ± 0.06 with litter v. 2.28 ± 0.09 without litter at 25 weeks). The results of this study showed that a high level of productivity and good egg quality could be obtained in large furnished cages. Further research is needed to assess the impact on hens' welfare and performance of using more economically competitive substrates than feed for litter.

Contamination flows of Bacillus cereus and spore-forming aerobic bacteria in a cooked, pasteurized and chilled zucchini purée processing line.

A food processing plant producing pasteurized purées and its zucchini purée processing line were examined for contamination with aerobic and facultative anaerobic bacterial spores during a day's operation. Multiplication of spores was also monitored in the product stored under different conditions. High concentrations of Bacillus cereus spores were found in the soil in which the zucchinis were grown (4.6+/-0.3 log CFU/g), with a background spore population of 6.1+/-0.2 log CFU/g. In the processing plant, no B. cereus or psychrotrophic bacterial spores were detected on equipment. B. cereus and psychrotrophic bacterial spores were detected after enrichment in all samples of raw zucchinis, washed zucchinis, of two ingredients (starch and milk proteins) and in processed purée at each processing step. Steam cooking of raw zucchinis and pasteurization of purée in the final package significantly reduced spore numbers to 0.5+/-0.3 log CFU/g in the processed food. During storage, numbers of spore-forming bacteria increased up to 7.8+/-0.1 log CFU/g in purée after 5 days at 20-25 degrees C, 7.5+/-0.3 log CFU/g after 21 days at 10 degrees C and 3.8+/-1.1 log CFU/g after 21 days at 4 degrees C. B. cereus counts reached 6.4+/-0.5 log CFU/g at 20-25 degrees C, 4.6+/-1.9 log CFU/g at 10 degrees C, and remained below the detection threshold (1.7 log CFU/g) at 4 degrees C. Our findings indicate that raw vegetables and texturing agents such as milk proteins and starch, in spite of their low levels of contamination with bacterial spores and the heat treatments they undergo, may significantly contribute to the final contamination of cooked chilled foods. This contamination resulted in growth of B. cereus and psychrotrophic bacterial spores during storage of vegetable purée. Ways to eliminate such contamination in the processing line are discussed.

Identification of bacteria in pasteurized zucchini purées stored at different temperatures and comparison with those found in other pasteurized vegetable purées.

One hundred nineteen isolates from a commercial zucchini purée stored at 4, 10, and 20 to 25 degrees C were fingerprinted using repetitive sequence-based PCR (REP-PCR) and classified into 35 REP types. One representative isolate of each REP type was subsequently identified by API50CHB/20E profile and partial rrs gene sequence analysis. Nine REP types were misidentified by the API system. Strains were misidentified as being in the Bacillus circulans (group 2) API taxon or in taxa with a low number of positive API characters such as Brevibacillus brevis. A phylogenetic analysis pointed to one new species of Bacillus and three new species of Paenibacillus among the misidentified REP types. Bacterial components in zucchini purée were compared phenotypically with those obtained in previous work on broccoli, carrot, leek, potato, and split pea purées, based on simple matching coefficient and unweighted pair group method with averages cluster analysis. Out of 254 strains, 69 strains previously identified as B. circulans (group 2) or B. circulans/B. macerans/B. polymyxa were assigned to a new Paenibacillus taxon phylogenetically related to P. azotofixans. Storage conditions at 4 degrees C favored the development of "B. macroides/B. maroccanus" and Paenibacillus spp. in zucchini purées and Paenibacillus spp. in other purées. Storage conditions at 20 to 25 degrees C favored the development of B. subtilis group (B. licheniformis and B. subtilis) and B. cereus group strains. At 10 degrees C, Paenibacillus spp. were always present at high frequencies, whereas the occurrence of B. macroides/B. maroccanus (in zucchini purées), B. cereus, and B. pumilus varied with the experiment.

Prevalence, characterization and growth of Bacillus cereus in commercial cooked chilled foods containing vegetables.

In cooked-chilled and pasteurized vegetable products, initial numbers of Bacillus cereus were below 10 cfu g-1. Before the appearance of spoilage, numbers reached 6-8 log cfu g-1 at 20 degrees C and 4-6 log cfu g-1 at 10 degrees C. Bacillus cereus was not detected in samples stored at 4 degrees C. Ten percent of strains isolated from the products were able to grow at 5 degrees C and 63% at 10 degrees C. Bacillus cereus strains unable to degrade starch, a feature linked to the production of emetic toxin, did not grow at 10 degrees C and had a higher heat resistance at 90 degrees C. Using immunochemical assays, enterotoxin was detected in the culture supernatant fluid of 97.5% of the strains. All culture supernatant fluids were cytotoxic but important variations in the level of activity were found. Psychrotrophic isolates of B. cereus were unable to grow in courgette broth at 7 degrees C whereas they grew in a rich laboratory medium. At 10 degrees C, these isolates grew in both media but lag time in courgette broth was 20-fold longer than in the rich laboratory medium.

Isolation and characterization of antagonists for the biocontrol of the postharvest wound pathogen Botrytis cinerea on strawberry fruits.

Antagonistic bacteria and yeasts were isolated from the epiphytic flora of stored strawberry fruits and evaluated for their ability to protect strawberry fruit wounds after harvest against Botrytis cinerea. Among selected potential antagonists, three strains of Candida reukaufii (5L3, 10CL4, 10L2) and one strain of Candida pulcherima (10L8) still protected fruit wounds when applied at 10(3) CFU/wound, reducing lesion or conidiophore development. In the same conditions, two Enterobacteriaceae (10B1, 5B4) highly reduced pathogen development. Strain 5B4 was still highly inhibitory when inoculated at 10(2) CFU/wound. The six strains applied on fruits did not produce any significant change in color, brightness, and firmness of fruits. The two yeasts, 5L3 and 10L8, and particularly the two bacteria, 5B4 and 10B1, were selected for further studies. The four antagonists effectively colonized fruit wounds and strongly inhibited spore germination of B. cinerea in vitro. The bacterial cells surrounded the germinating spores of B. cinerea and attachment of 5L3 cells on germinating spores were additionally observed. Bacterial antagonists, particularly the strain 5B4, multiplied and rapidly used carbohydrates in strawberry fruit juice despite the low pH (pH 3.5). The efficiency of the bacterial antagonists on fruit wounds was related to their growth and nutritional properties.

Cloning of a large gene cluster involved in Erwinia amylovora CFBP1430 virulence.

Phage MudIIPR13 insertional mutagenesis of Erwinia amylovora CFBP1430 allowed us to isolate 6900 independent CmR mutants. The frequencies of different auxotrophs in this population indicated that MudIIPR13 had inserted randomly in E. amylovora. Screening of 3500 CmR mutants on (i) apple calli and (ii) pear and apple seedlings led to the isolation of 19 non-pathogenic prototrophic single mutants, four of which expressed a LacZ+ hybrid protein. Expression of the fusion proteins was temperature sensitive. The 19 mutants could be separated into two classes according to their behaviour on tobacco: 13 were unable to elicit the hypersensitive response on tobacco (Hrp-) while six still could (Dsp-). The 19 MudIIPR13 insertions all mapped in the same virulence region. The MudIIPR13 insertions of Hrp- mutants were all clustered on the left part of this region, while the MudIIPR13 insertions of Dsp- mutants were located on the right part. All of the mutants except one, which proved to have a large deletion of the entire virulence region, could be complemented functionally by cosmids from an E. amylovora CFBP1430 genomic library. No hybridization was observed between the cosmid pPV130, which complemented 12 hrp::MudIIPR13 mutations, and the hrp genes from Pseudomonas syringae pv. phaseolicola (Lindgren et al., 1986), P. syringae pv. tomato (N.J. Panopoulos, unpublished data) or P. solanacearum (Boucher et al., 1987). Further analysis of the large virulence region will allow mapping of the border of the virulence region and facilitate the study of the function and regulation of the hrp and dsp genes.