The role of whey on the performance and campylobacteriosis in broiler chicks.

The objective of the present study was to investigate the effect of the whey on broiler chicks' performance, welfare, and caecal Campylobacter counts under experimental and field conditions. In the experimental study, 120-d-old broiler chicks were randomly allocated to four treatment groups, as described below: group A, which served as negative control; group B, fed with a diet supplemented with 1% whey; group C, challenged with Campylobacter jejuni; and group D, supplemented with 1% whey and challenged with C. jejuni, respectively. Performance indexes and caecal C. jejuni counts were calculated. In addition to the performance indexes, the hock burn and the foot pad dermatitis lesions score were measured to assess the welfare status of broiler chicks. In order to evaluate the use of whey under field conditions, a second study was performed in a broiler farm with two identical houses. The evaluation of the experimental data revealed that the use of whey did not affect significantly the performance (P ≤ 0.05) and the caecal C. jejuni counts (P ≤ 0.05). There were neither footpad dermatitis lesions nor hock burn lesions in any of the experimental groups. In the field study, the use of whey had no effect on the performance indexes (P ≤ 0.05). It can be concluded that the addition of whey has no negative effect on poultry and may provide an alternative natural feed additive for the broiler feed industry.

Heat stress as a predisposing factor for necrotic enteritis in broiler chicks.

Heat stress is a physical environmental stressor, which can affect performance, health and welfare of poultry. The present study investigates the effect of cyclic acute heat stress as a predisposing factor for necrotic enteritis in broiler chicks in an experimental challenge model. Two hundred and forty broiler chicks were randomly allocated to four treatment groups, as follows: group A served as negative control (25°C), group B birds were subjected to cyclic acute heat stress (35°C), group C birds were challenged and group D birds were both subjected to heat stress and challenged. From each bird, the intestine, gizzard and liver were collected and scored for gross lesions. The intestinal digesta was collected for pH and viscosity determination. One caecum from each bird was taken for microbiological analysis. The statistical analysis and evaluation of data revealed that the heat stress in challenged birds showed a relative trend to increase the severity and the incidence of necrotic enteritis lesions, although it was not considered as statistically significant (Ρ = 0.077). Additionally, the heat stress induced necrotic enteritis outbreak in unchallenged birds; the challenge of birds as well as its combination with the heat stress affected significantly (Ρ ≤ 0.05) the pH and viscosity of intestinal digesta and the caecal Clostridium perfringens counts. The study provides evidence that cyclic acute heat stress is an environmental stressor, which can significantly affect necrotic enteritis and gut health, and thus should be taken into account in warmer areas of the world where poultry farming becomes a major industry.

Effects of lysolecithin supplementation in low-energy diets on growth performance, nutrient digestibility, viscosity and intestinal morphology of broilers.

1. The study aimed to investigate the effect of lysolecithin supplementation in low-energy diets on growth, nutrient digestibility and intestinal mucosa characteristics of broilers. 2. A total of 800 one-d-old Ross 308 broiler chickens were assigned to 4 dietary treatments consisting of 10 replicates of 20 broilers each. Broilers were fed with 4 different diets: (i) HE: positive control group broilers received a diet with unaltered energy; (ii) LE: negative control group broilers received a diet with lower energy of about 0.27 MJ/kg; (iii) LElys500: broilers received a diet similar to LE supplemented with 500 g/tn lysolecithin product (Lysoforte Booster DryTM); and (iv) LElys300: broilers received a diet similar to LE supplemented with 300 g/tn lysolecithin product. The experimental period was 42 d. 3. Body weight gain in treatments HE was higher than LE during the overall experimental period, while LElys500 and LElys300 had intermediate values. Feed conversion ratio was lower in HE and LElys500 than LE group, while the LElys300 had intermediate values. Fat digestibility was improved in both LElys 500 and LElys300 compared to the HE group. Apparent metabolisable energy (AMEn) was higher in HE, LElys500 and LElys300 than LE. Ileum viscosity at 42 d was also affected, being higher in LE group compared to HE. At 28 d mucosal thickness was lower both in LElys500 and LElys300 compared to HE and LE, while no difference occurred between treatment proliferation patterns of duodenal epithelial cells. 4. These findings indicated that lysolecithin supplementation at 500 g/tn of feed in low-energy diets maintained broiler performance. Supplementation of reformulated low-energy diets induced an increase in digesta viscosity. Lysolecithin supplementation resulted in variable alterations in the duodenum mucosal morphology.

The effect of cold stress on the pathogenesis of necrotic enteritis in broiler chicks.

Cold stress is a physical environmental stressor with significant effect on the poultry industry. The aim of the present study was to investigate the effect of cold stress as a predisposing factor for necrotic enteritis in broiler chicks. The experimental challenge model included an oral inoculation with 10-fold dose of attenuated anticoccidial vaccine and multiple oral inoculations with a specific strain of Clostridium perfringens. Birds were either challenged or not as described above, and either exposed or not to repeated cold stress (15°C for 12 h/day for 4 days). From each bird, intestinal gross lesions were scored and intestinal digesta pH and viscosity were measured. C. perfringens was counted in the caecum. The statistical analysis and evaluation of the experimental data revealed that the cold stress in challenged birds significantly increased the incidence and the severity of necrotic enteritis lesions (Ρ ≤ 0.05), while causing no lesions in unchallenged birds. Moreover, the cold stress caused a significant increase (Ρ ≤ 0.05) in the pH and C. perfringens counts in the caeca. The study provides evidence that cold stress increased the susceptibility to necrotic enteritis in a subclinical experimental model and thus should be regarded as a physical environmental stressor that could significantly affect the welfare, health and intestinal ecosystem of broiler chicks.

High stocking density as a predisposing factor for necrotic enteritis in broiler chicks.

Stocking density is a management factor which has critical implications for the poultry industry. The aim of the present study was to investigate the effect of high stocking density as a predisposing factor in an experimental model of necrotic enteritis in broiler chicks. The experimental challenge model included an oral inoculation with 10-fold dose of attenuated anticoccidial vaccine and multiple oral inoculations with a specific strain of Clostridium perfringens. Two hundred and forty as hatched day-old broiler chicks were randomly allocated to four treatment groups according to the following experimental design: group N, with normal stocking density (15 birds/m(2)) and no challenge; group D, with high stocking density (30 birds/m(2)) and no challenge; group P, with normal stocking density and positive challenge; and group DP, with high stocking density and positive challenge. From each bird, the intestine, gizzard and liver were collected and scored for gross lesions. The intestinal digesta was collected for pH and viscosity determination. One caecum from each bird was taken for microbiological analysis. The statistical analysis and evaluation of the experimental data revealed significant interaction effects between "stocking density" and "challenge", regarding gross lesion scores in intestine and liver, pH values in jejunum, ileum and caeca as well as C. perfringens counts in the caeca (P ≤ 0.05). High stocking density in challenged birds increased the gross lesion score in the intestine (P ≤ 0.05), contrary to unchallenged birds. It can be concluded that high stocking density affects unfavourably the welfare and gut health of broiler chicks, predisposes to necrotic enteritis in a subclinical experimental model and increases further its importance as a management factor for the poultry industry.

Temporary feed restriction partially protects broilers from necrotic enteritis.

The objective of this study was to investigate the effect of feed restriction on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chicks. To induce subclinical necrotic enteritis, an experimental challenge model using a specific diet formulation, Gumboro vaccination, oral inoculation of broilers with a 10-fold dose of attenuated anticoccidial vaccine and multiple oral inoculations with a specific strain of Clostridium perfringens was adopted. Two hundred and forty 1-day-old Cobb 500 broilers were randomly allocated to four groups: feed restricted, challenged, both feed restricted and challenged, and negative control. At 21, 22, 23 and 24 days of age, the intestines, gizzard and liver were collected from 15 birds in each group and scored for gross lesions. The intestinal digesta was collected for pH and viscosity determination. One caecum from each bird was taken for microbiological analysis. The application of feed restriction in birds challenged with C. perfringens reduced the necrotic enteritis lesion score significantly (P ≤ 0.05) and feed restriction significantly reduced (P ≤ 0.05) pH in the small intestine, the viscosity of the jejunum digesta as well as the C. perfringens counts in the caeca compared with the controls. In conclusion, feed restriction of broilers has a positive effect on the intestinal ecosystem and a significant protective effect against necrotic enteritis in the subclinical experimental model.

The role of an attenuated anticoccidial vaccine on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chickens.

The objective of the present study was to investigate the effect of an attenuated anticoccidial vaccination on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis (NE) in broiler chickens. Two hundred and forty 1-day-old Cobb 500 broiler chickens were randomly allocated to four treatment groups according to the following experimental design: control Group N; Group PN, where birds were vaccinated with anticoccidial vaccine; Group M, where birds were challenged with Clostridium perfringens and with Eimeria maxima; and Group PM, where birds were both vaccinated and challenged. From each bird, the intestine, gizzard and liver were scored for gross NE lesions. Intestinal digesta were collected for pH and viscosity determination. Samples from the gastrointestinal tract and liver were taken for microbiological analysis. Evaluation of the experimental data revealed that Group M had significantly higher overall mean NE intestinal lesions compared with Group PM. Viscosity values of jejunum digesta as well as pH values of the duodenum, jejunum and ileum digesta in Group M were significantly lower compared with Group PM. C. perfringens counts in the caeca of Group PM were significantly lower compared with Group M. The milder decrease of pH and viscosity values of intestinal content and the reduction of C. perfringens counts in the caeca in challenged and vaccinated birds may explain the lower score of NE gross intestinal lesions and may suggest a positive effect on intestinal ecosystem and a significant protective effect of attenuated anticoccidial vaccination against NE in a subclinical experimental model.