Ammonia concentrations, litter quality, performance and some welfare parameters of broilers kept on different bedding materials.

1. Litter quality has been related to broiler performance, behaviour, welfare, dust and ammonia (NH3) emissions. Drier litter leads to a reduction in NH3 emissions and reduces the formation of foot- and hock lesions. However, maintaining good litter quality is often challenging. This study investigated the effects of different bedding materials on litter quality and NH3 concentrations at litter level, broiler performance, foot- and hock lesions, plumage cleanliness and breast skin irritation.2. A total of 2160 Ross 308 male broilers were randomly assigned to 36 floor pens. There were six replications for each of the following six litter treatments: wood shavings, flax, peat, maize silage, chopped wheat straw and flax pellets.3. For the total period, the highest feed intake and body weight was obtained for broilers housed on peat. The NH3 concentrations measured at litter level was highest for peat and chopped wheat straw at 36 d of age and numerically the lowest for flax at 30 and 36 d of age. Maize silage remained friable, but did not result in lower NH3 concentrations compared to wood shavings. Chopped wheat straw and wood shavings gave rise to the highest incidence of foot lesions at 38 d of age, while broilers kept on flax, peat, maize silage and flax pellets had the lowest incidence of foot lesions at the end of the rearing period.4. The results of the current study suggest a complicated relationship between the type of bedding material, litter conditions and NH3 volatilised from the litter.

Assessing keel bone damage in laying hens by palpation: effects of assessor experience on accuracy, inter-rater agreement and intra-rater consistency.

Accurate assessment is essential when evaluating keel bone damage. Palpation is commonly used to assess keel bone damage in living hens. However, there is little information on the accuracy of assessment of deviations and fractures on different parts of the keel, and on the consistency within, and agreement between, assessors. Crucially, although the importance of experience is commonly emphasized, knowledge on its effect is scarce. Ten assessors with or without prior experience palpated the same 50 75-wk-old hens for deviations, medial fractures, and caudal fractures (scored as present/absent). Accuracy, sensitivity, specificity, precision, and negative predictive value were determined by comparing palpation scores to post-dissection assessment, and then compared between experienced and inexperienced assessors. To determine the effect of the experience gained during the experiment, hens were subsequently re-assessed. Consistency within, and agreement between, assessors were also determined. Assessors with prior experience were more accurate (proportion of accurately assessed deviations: experienced 0.83 vs. inexperienced 0.79±0.01, P = 0.04; medial fractures: 0.82 vs. 0.68±0.03 in session 1 only, P = 0.04; caudal fractures: 0.41 vs. 0.29±0.03, P = 0.03), and inexperienced assessors classified medial fractures more accurately in session 2 (session 1: 0.68 vs. session 2: 0.77±0.04, P = 0.04). However, effect sizes were small for deviations and even experienced assessors lacked accuracy when assessing caudal fractures. Unexpectedly, deviations tended to be assessed more accurately in session 1 than in session 2, regardless of assessor status (1: 0.83 vs. 2: 0.79±0.01, P = 0.06), suggesting that prolonged assessment contributes to errors. Prior experience decreased specificity and precision of fracture assessment (more unfractured keels were classified as fractured) even though overall accuracy was greater. Intra-rater consistency was fair to good (0.55 to 0.67) for deviations and medial fractures, but poor to fair (0.36 to 0.44) for caudal fractures, and unaffected by prior experience (P = 0.49 to 0.89). In conclusion, experience improves accuracy to a limited extent but does not guarantee high accuracy for all types of damage. Future research should determine if other training methods (e.g., comparison to post-dissection scores or to radiographs) improve accuracy.

Interactions between the concentration of non-starch polysaccharides in wheat and the addition of an enzyme mixture in a broiler digestibility and performance trial.

Two broiler trials were designed to investigate the relationship between the concentration of non-starch polysaccharides (NSP) in wheat and 1) its nutritional value for broilers and 2) the efficacy of exogenous enzymes. In a balance trial, diets were formulated with 3 wheat cultivars (Rustic and Viscount-medium NSP, Centenaire-high NSP) and were tested with or without the addition of an exogenous enzyme mixture. The diets were fed to 144 male Ross 308 broiler chickens housed in digestibility cages. Total tract nutrient digestibilities and AMEn were measured from 18 to 22 d of age. In a performance trial, diets were formulated with wheat (medium NSP diet) or with wheat mixed with rye and barley (high NSP diet) and were tested with or without the addition of an exogenous enzyme mixture. The diets were fed to 960 male Ross 308 broilers housed in pens and broiler performance during starter, grower and finisher periods was measured.In the balance trial, wheat cultivar did not affect nutrient digestibility or AMEn. Enzyme addition caused a significant increase in nutrient digestibilities and AMEn for the diet formulated with the high NSP wheat Centenaire only. In the performance trial, feeding the high NSP diet resulted in a higher feed conversion ratio and lower final body weight compared to the medium NSP diet. The largest improvements by enzyme addition were observed in the high NSP diet.In conclusion, the study was not able to show a consistent relationship between the NSP concentration of wheat and its nutritional value, but did demonstrate that the effect of an enzyme mixture on nutrient digestibility or broiler performance depends upon the NSP concentration in the diet.

Effect of different split-feeding treatments on performance, egg quality, and bone quality of individually housed aged laying hens.

In order to try to combat the effect of age on eggshell quality in aged laying hens, 5 split-feeding treatments were compared with conventional feeding between 75 and 92 wk of age. In the conventional treatment (T1), the same morning (M) and afternoon (A) diet was fed containing fine (FL) and coarse (CL) limestone at a 50:50 ratio. In the split treatments, the ratio of FL and CL was 50:50 or 30:70, and time of administration (M/A) differed. The following treatments were given: T2 = 50FL-M:50CL-A, T3 = 50CL-M:50FL-A, T4 = 30FL-M:20FL-A+50CL-A, T5 = 30FL-M:70CL-A, and T6 = 0M:30FL-A+70CL-A. A total of 12 individually housed Dekalb white hens was used per treatment. Feed intake, nutrient intake, and laying % was lower in T1 compared to all split treatments (P ≤ 0.001). Due to this low performance in T1, split feeding could not be compared to the conventional system in this trial. By the end of the trial, eggshell quality was improved in T1 as a result of low laying % and more frequent and longer laying pauses. In the split treatments, laying % and feed intake were similar, except in T3 in which a decrease was observed after 81 wk (P ≤ 0.05). Egg weight was higher in T5 and T6 due to higher total and morning protein intake compared to T3 (P ≤ 0.05). Feeding only 50FL-A in T3 not only resulted in lower performance but also in consistently lower shell thickness, indicating a negative effect of suboptimal limestone supplementation. In the split-feeding system, the most optimal combination of morning and afternoon diet was a morning diet with only FL and an afternoon diet with only CL (T2), which both provided ∼50% of the total daily Ca intake. Shell breaking strength and dynamic stiffness could be maintained on this diet between 75 and 92 weeks. Decreasing the amount of Ca in the morning and increasing it in the afternoon did not improve shell quality traits. Bone quality was not affected by limestone particle size or inclusion level in the split-feeding system.

Results of an international phosphorus digestibility ring test with broiler chickens.

The objective of this ring test was to investigate the prececal phosphorus (P) digestibility of soybean meal (SBM) in broiler chickens using the trial protocol proposed by the World's Poultry Science Association. It was hypothesized that prececal P digestibility of SBM determined in the collaborating stations is similar. Three diets with different inclusion levels of SBM were mixed in a feed mill specialized in experimental diets and transported to 17 collaborating stations. Broiler chicks were raised on commercial starter diets according to station-specific management routine. Then they were fed the experimental diets for a minimum of 5 d before content of the posterior half of the ileum was collected. A minimum of 6 experimental replicates per diet was used in each station. All diets and digesta samples were analyzed in the same laboratory. Diet, station, and their interaction significantly affected (P < 0.05) the prececal digestibility values of P and calcium of the diets. The prececal P digestibility of SBM was determined by linear regression and varied among stations from 19 to 51%, with significant differences among stations. In a subset of 4 stations, the prececal disappearance of myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)-P; InsP6-P) also was studied. The prececal InsP6-P disappearance correlated well with the prececal P digestibility. We hypothesized that factors influencing InsP6 hydrolysis were main contributors to the variation in prececal P digestibility among stations. These factors were probably related to the feeding and housing conditions (floor pens or cages) of the birds in the pre-experimental phase. Therefore, we suggest that the World's Poultry Science Association protocol for the determination of digestible P be should extended to the standardization of the pre-experimental period. We also suggest that comparisons of P digestibility measurements among studies are made only with great caution until the protocol is more refined.

Supplementation of fine and coarse limestone in different ratios in a split feeding system: Effects on performance, egg quality, and bone strength in old laying hens.

Different ratios of fine- (FL) and coarse limestone (CL) were compared (50FL:50CL, 30FL:70CL, 0FL:100CL) in conventional (C) and split feeding (S) for their effects on performance, egg quality traits, and bone quality of old, brown laying hens (72 to 83 wk). Each treatment consisted of 42 hens (7 hens × 6 replicates). In the C system diets supplemented with limestone were provided during the whole day, whereas in the S system a morning diet was fed without added limestone, and only the afternoon diet was supplemented with different limestone ratios. Highest laying %, egg mass, and lowest feed conversion were found in the C system with 50FL:50CL and 0FL:100CL and in the S system with 30FL:70CL between 76 and 79 wk (P ≤ 0.001). Reduced cracked egg % was found when 0FL:100CL was supplemented in the C system and 30FL:70CL in the S system between 72 and 83 wk (P ≤ 0.001). Tibia ash content was higher in the S system compared to the C system (P = 0.005); tibia breaking strength, however, did not differ between feeding systems. Egg quality traits were not improved by S feeding. However, at 83 wk, S feeding resulted in higher breaking strength, but lower shell thickness compared to the C system (P = 0.036, P ≤ 0.001, respectively). Therefore, hens in the S feeding system might have been able to form a structurally superior shell compared to the C system. For further investigation, instead of restricting limestone supplementation solely to the afternoon, it might be a better approach to provide FL and CL at a different time of the d in a split feeding system to improve shell quality in old, brown laying hens in an extended production cycle.

Changes in egg quality traits during the last phase of production: is there potential for an extended laying cycle?

1. A field study was conducted to investigate the deterioration of eggshell quality at the end of lay and examine the potential to extend the production cycle. A total of 1200 eggs were assessed originating from commercial farms in Belgium: eggs were random sampled at the collection belt at 57-65 weeks of age and at the end of the production cycle (74-92 weeks). 2. Based on a linear mixed model, egg quality was estimated for an average flock at 60 weeks of age and changes in quality traits were predicted until the end of the laying cycle. 3. Egg weight increased by 0.07 g every week from 60 weeks of age onwards and shape index decreased by 0.04 unit weekly (P < 0.001). Haugh unit values decreased weekly by 0.38 units whereas relative yolk weight was unaffected after 60 weeks of age. Relative albumen weight showed a weekly increase of 0.02% and relative shell decreased by 0.02% weekly until the end of lay. 4. Shell quality traits were also influenced by age: shell index decreased by 0.013 g weekly, shell thickness was calculated to be 0.23 µm thinner every week, deformation increased by 0.06 µm weekly from 60 weeks to the end of the laying cycle. Variability of the deformation of eggs indicated more heterogeneous shell quality at the end of the production cycle. Dynamic stiffness increased from 60 weeks of age on. 5. Laying hens were depopulated on average at 80 weeks of age (varying from 74-92 weeks). Although ageing had a significant effect on most of the egg quality traits, egg quality was still acceptable at the end of lay, indicating the potential to extend the laying cycle.

Ramps and hybrid effects on keel bone and foot pad disorders in modified aviaries for laying hens.

Non-cage systems provide laying hens with considerable space allowance, perches and access to litter, thereby offering opportunities for natural species-specific behaviors. Conversely, these typical characteristics of non-cage systems also increase the risk of keel bone and foot pad disorders. The aim of this study was twofold: 1) to investigate if providing ramps between perches (housing factor) reduces keel bone and foot pad disorders and 2) to test for genetic predisposition by comparing 2 different layer hybrids. In a 2 × 2 design, 16 pens were equipped either with or without ramps between perches and nest boxes (8 pens/treatment), and housed with either 25 ISA Brown or Dekalb White birds per pen (in total 200 birds/hybrid). Keel bone injuries and foot health were repeatedly measured via palpation and visual assessment between 17 and 52 wk of age and daily egg production was recorded. The relationships between the dependent response variables (keel bone and footpad disorders, egg production) and independent factors (age, ramps, hybrid) were analyzed using generalized linear mixed models and corrected for repeated measures. Ramps reduced keel bone fractures (F1,950 = 45.80, P < 0.001), foot pad hyperkeratosis (F1,889 = 10.40, P = 0.001), foot pad dermatitis (F1,792 = 20.48, P < 0.001) and bumble foot (F1,395 = 8.52, P < 0.001) compared to pens without ramps. ISA Brown birds sustained more keel bone fractures (F1,950 = 33.26, P < 0.001), had more foot pad hyperkeratosis (F1,889 = 44.69, P < 0.001) and laid more floor eggs (F1,1883 = 438.80, P < 0.001), but had fewer keel bone deviations (F1,1473 = 6.73, P < 0.001), fewer cases of foot pad dermatitis (F1,792 = 19.84, P < 0.001) and no bumble foot as compared to Dekalb White birds. Age, housing and hybrid showed several interaction effects. Providing ramps proved to be very effective in both reducing keel bone and foot pad problems in non-cage systems. Keel bone and foot pad disorders are related to genetic predisposition. These results indicate that adaptation of the housing systems and hybrid selection may be effective measures in improving laying hen welfare.

Vegetative Bacillus amyloliquefaciens cells do not confer protection against necrotic enteritis in broilers despite high antibacterial activity of its supernatant against Clostridium perfringens in vitro.

In this study, the effect of Bacillus amyloliquefaciens on Clostridium perfringens was tested in vitro and in vivo. Using an agar well diffusion assay, the inhibitory activity of B. amyloliquefaciens supernatant was analysed against a large collection of netB-positive and netB-negative C. perfringens strains. Although strong growth inhibiting activity was detected against all C. perfringens isolates, it was significantly higher against virulent netB-positive C. perfringens strains compared with avirulent netB-negative isolates. Subsequently, the efficacy of in-feed administration of lyophilised vegetative cells of B. amyloliquefaciens to prevent necrotic enteritis was tested in vivo using an established experimental infection model in broilers. Ross 308 broilers received either B. amyloliquefaciens supplemented or unsupplemented feed throughout the experiment. No significant differences could be detected between the untreated positive control group and the B. amyloliquefaciens treated group in body weight, the number of chickens that developed necrotic lesions and in pathological lesion scores. These results demonstrate that despite its substantial inhibitory activity in vitro, lyophilised vegetative B. amyloliquefaciens cells had no beneficial effect against necrotic enteritis in the in vivo model used here.

Does release of encapsulated nutrients have an important role in the efficacy of xylanase in broilers?

The non-starch polysaccharides (NSPs) in cell walls can act as a barrier for digestion of intracellular nutrients. This effect is called "cage effect." Part of the success of fibrolytic enzymes in broiler feed is assumed to be attributed to cage effect reduction. Further, changes in viscosity and potential prebiotic action should also be considered. The aim of this study was to gain insight into the relative importance of the cage effect in xylanase efficacy in broilers. Using a 2×2 factorial design, 24 pens with 30 Ross 308 male chicks were fed corn-soy based diets consisting of normal and freeze-thawed (5 d at -18°C) corn, both with and without xylanase. The freeze-thaw method was used to eliminate the cage effect, whereas a corn-based diet was used to exclude viscosity effects. Body weights (BW), feed intake (FI), and feed conversion ratio (FCR) were determined at d 13, 26, and 39. A balance study was executed at the end of the growing phase. These birds were euthanized at d 34 (non-fasted) to determine the viscosity of digesta, blood metabolites, intestinal morphology, and microbiota composition. During the finisher period, there was a significant interaction between enzyme supplementation and freeze-thawing for FCR, in which FCR was improved by freeze-thawed corn and tended to be improved by normal corn+enzyme compared with the control group. The improvement in performance (finisher period) of freeze-thawed corn and xylanase coincided with increased gut absorption of glucose (based on postprandial plasma concentrations) and increased number of Clostridiumcluster IV in the caecum, and agreed with the higher gut villus height. In addition, xylanase inclusion significantly increased the postprandial plasma glycine and triglycerides concentration, and led to elevated bacterial gene copies of butyryl CoA:acetate CoA-transferase, suggesting a prebiotic effect of xylanase addition through more than just the cage effect reduction. The applied model managed to rule out viscosity by using corn, and it was possible to isolate the cage effect by freeze-thawing the dietary corn.

Can breeder reproductive status, performance and egg quality be enhanced by supplementation and transition of n-3 fatty acids?

The aim of this experiment was to investigate the effect of n-3 fatty acid (FA) supplemented diets on breeder performance, productivity and egg quality. Breeders (n = 480) were fed the supplemented diet from 18 weeks onwards; the inclusion level of n-3 FA was increased from 1.5% to 3.0% from 34 weeks of age onwards until 48 weeks of age. Ross-308 broiler breeders (n = 480) were fed one of four different diets: a basal diet rich in n-6 FA (control diet) or one of three diets rich in n-3 FA. For the n-3 FA diets, eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) were fed to the broiler breeders at different ratios formulated to obtain EPA/DHA ratios of 1/1, 1/2 or 2/1. Differences in performance, reproduction and egg quality parameters due to n-3 supplementation were noted more for the 1.5% followed by the 3.0% fed broilers than their 1.5% supplemented counterparts. Egg weight (p < 0.001) and egg mass (p = 0.003) were significantly lower and feed conversion (p = 0.008) significantly higher for the n-3 FA (at 3.0% inclusion level) fed broilers compared to the control group. For the EPA- and DHA-fed breeders, a higher proportional abdominal fat percentage (p = 0.025) and proportional albumen weight (%) (p = 0.041) were found respectively. Dietary treatments did not affect reproduction. It can be concluded that the results of the present experiment indicate no significant differences between treatments at 1.5% inclusion levels. However, increasing this level to 3.0% is not recommended due to the rather negative effects on the measured parameters. It should be further investigated whether these adverse effects were obtained due to (i) the higher supplementation level, (ii) combining a supplementation level of 1.5% with 3% or (iii) the duration of supplementation.

Risk factors associated with keel bone and foot pad disorders in laying hens housed in aviary systems.

Aviary systems for laying hens offer space and opportunities to perform natural behaviors. However, hen welfare can be impaired due to increased risk for keel bone and foot pad disorders in those systems. This cross-sectional study (N = 47 flocks) aimed to assess prevalences of keel bone and foot pad disorders in laying hens housed in aviaries in Belgium to identify risk factors for these disorders and their relation to egg production. Information on housing characteristics and egg production were obtained through questionnaire-based interviews, farm records, and measurements in the henhouse. Keel bone (wounds, hematomas, fractures, deviations) and foot pad disorders (dermatitis, hyperkeratosis) were assessed in 50 randomly selected 60-week-old laying hens per flock. A linear model with stepwise selection procedure was used to investigate associations between risk factors, production parameters, and the keel bone and foot pad disorders. The flock mean prevalences were: hematomas 41.2%, wounds 17.6%, fractures 82.5%, deviations 58.9%, hyperkeratosis 42.0%, dermatitis 27.6%, and bumble foot 1.2%. Identified risk factors for keel bone disorders were aviary type (row vs. portal), tier flooring material (wire mesh vs. plastic slats), corridor width, nest box perch, and hybrid. Identified risk factors for foot pad disorders were aviary type (row vs. portal), free-range, and hybrid. Percentage of second-quality eggs was negatively associated with keel bone deviations (P = 0.029) at the flock level. Keel bone and foot pad disorders were alarmingly high in aviary housing. The identification of various risk factors suggests improvements to aviary systems may lead to better welfare of laying hens.

Relationship between wheat characteristics and nutrient digestibility in broilers: comparison between total collection and marker (titanium dioxide) technique.

Three wheat cultivars (Orpheus, Rustic, and Viscount) were used to formulate 3 test feeds (62.4% wheat) in a broiler digestibility trial. The diets were fed to male Ross 308 broiler chickens. The wheat cultivars mainly differed in their amount of non-starch polysaccharides ( NSP: ). The cultivar Orpheus was chosen to represent a high amount of NSP (102 g/kg DM), whereas the cultivars Rustic and Viscount represented low amounts of NSP (83.4 g/kg DM and 73.9 g/kg DM, respectively). Furthermore, the cultivars Orpheus and Viscount were feed quality wheat, whereas Rustic was a milling quality wheat. Nutrient digestibilities and AMEn contents of the diets were measured from 18 to 22-days-old by total excreta collection, or with the use of the indigestible marker titanium dioxide. In addition, the ileal viscosity was measured when the broilers were 25-days-old. Wheat cultivar affected N retention, DM digestibility, and AMEn. In general, the feed formulated with the high NSP wheat cultivar Orpheus resulted in the least favorable nutrient digestibilities and AMEn, whereas the results were better when the feed was formulated with the low NSP cultivars Viscount and Rustic. Feeding the Rustic cultivar caused the highest intestinal viscosity, although this was not reflected in the animal responses. Nutrient digestibilities and AMEn content of the diets were lower when calculated with the titanium dioxide marker than with the total excreta collection procedure. Moreover, the P-values of the effect of wheat cultivar on DM digestibility, N retention, crude fat digestibility and AMEn were lower with the use of the titanium dioxide marker. It can be concluded that wheat cultivar affected nutrient digestibility and AMEn, and that the observed differences were related to the amount of NSP. Furthermore, both the titanium dioxide marker and the total excreta collection methods showed the same trends despite the different values obtained. The titanium dioxide marker method was the simplest to use and produced valid results.

Effects of maternal dietary EPA and DHA supplementation and breeder age on embryonic and post-hatch performance of broiler offspring: age and n-3 pufa affect embryonic and post-hatch performance.

Breeder age and nutrition are amongst the most important factors affecting progeny growth and development. The present experiment was carried out to evaluate the effects of n-3 fatty acid (FA), with special emphasis on the ratio of eicosapentaenoic (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3) acid, provided to the diet of ageing broiler breeder hens at different ratios, on the incubation parameters and the performance of the offspring. Four hundred and eighty Ross-308 broiler breeder hens were fed one of four different diets (120/treatment), with an equal fat content. The control diet was a basal diet, rich in n-6 FAs (CON). Blends of fish oil were used to enrich the three other diets in n-3 FA and to obtain different EPA/DHA ratios of 1/1 (EPA=DHA), 1/2 (DHA) or 2/1 (EPA). Every 5 weeks, incubation parameters were assessed. Every 15 weeks, offspring was reared until slaughter age on a standard diet. Breeder age affected almost all incubation and post-hatch parameters, whereas n-3 FA treatment only lowered egg weight (p < 0.0001) and consequently hatched chick weight (p < 0.0001). Supplementation of EPA resulted in a higher proportional liver weight (p = 0.0219) at hatch, a lower body weight up to 28 days post-hatch (p = 0.0418), a lower daily weight gain (p = 0.0498) and a higher feed conversion ratio (p = 0.0395) during the starter period (p = 0.0498), resulting in a higher overall offspring feed conversion ratio (p = 0.0317) compared to the control diet. DHA supplementation, on the other hand, resulted in a lower residual yolk weight (p = 0.0220) and a higher overall offspring mortality (p = 0.0125). In conclusion, supplementation of n-3 FA could not counter the adverse effect of breeder flock age, but did not harm incubation or improve post-hatch performance, either. EPA and DHA affected offspring development differently during early post-hatch life.

The interaction between maternal and post-hatch n-3 fatty acid supplementation in broiler diets.

This study investigated whether offspring from n-3-supplemented breeders have an enhanced performance and immune organ weight when fed a post-hatch n-3-enriched diet in comparison with their control-fed counterparts and the importance of timing of omega-3 supplementation. Therefore, 480 Ross-308 broiler breeder hens were fed one of four different diets (120/treatment). The control diet (CON) was a basal diet, rich in n-6 fatty acids (FA). The three other diets were enriched in n-3 FA, formulated to obtain a different EPA/DHA ratio of 1/1 (EPA = DHA), 1/2 (DHA) or 2/1 (EPA). At 33 weeks of age, eggs were incubated to obtain 1440 offspring. They were set up according to their maternal diet and sex in 48 pens of 30 chicks each (12 pens per maternal treatment: six male and six female). Half of the offspring were given a post-hatch control diet, whereas to other half received an n-3-supplemented diet. Zootechnical performance was followed for starter, grower and finisher phase, and at the end of each phase two, chicks per pen were sacrificed to determine the weight of the immune organs. No interaction was found between maternal and post-hatch n-3 treatment for zootechnical performance. An interaction arose between the maternal and post-hatch n-3 supplementation for proportional bursa weight at day 1 and day 14 and proportional liver weight at day 14, but effects on immune organ weight were rather limited. Offspring post-hatch n-3 supplementation did not enhance maternal n-3 supplementation.

Challenge with lipopolysaccharides or Freund's adjuvant? What is the best option to trigger acute phase protein production in broilers?

Broilers were injected at 10 days of age with either Escherichia coli lipopolysaccharides (LPS) or with Freund's adjuvants (FA) to investigate its triggering effect on the acute phase reaction (APR). First the kinetics of certain APP was studied by sampling blood 4 h, 8 h, 12 h and 24 h post injection with LPS. Ovotransferrin (OVT) and α-1 acid glycoprotein (AGP) concentration increased with time post injection (PI) with LPS to reach a plateau at 12 and 24 h PI. Caeruloplasmin (CP) did not increase with time PI. Compared to injection with phosphate buffered saline, OVT concentrations were higher when injecting chicks with LPS at all time points PI. At 24 h PI, LPS injection resulted in higher OVT and AGP concentration compared to injection with FA. It is recommended to use LPS instead of FA to trigger the APR. The best time point to sample blood for APP determination is 24 h PI.

[Withdrawal of artificial nutrition and hydration in severe stroke: medical, legal and ethical considerations]. / Aspects médicaux, législatifs et éthiques de l'arrêt de la nutrition et de l'hydratation artificielles dans l'accident vasculaire cérébral grave.

In the majority of cases, severe stroke is accompanied by difficulty in swallowing and an altered state of consciousness requiring artificial nutrition and hydration. Because of their artificial nature, nutrition and hydration are considered by law as treatment rather basic care. Withdrawal of these treatments is dictated by the refusal of unreasonable obstinacy enshrined in law and is justified by the risk of severe disability and very poor quality of life. It is usually the last among other withholding and withdrawal decisions which have already been made during the long course of the disease. Reaching a collegial consensus on a controversial decision such as artificial nutrition and hydration withdrawal is a difficult and complex process. The reluctance for such decisions is mainly due to the symbolic value of food and hydration, to the fear of "dying badly" while suffering from hunger and thirst, and to the difficult distinction between this medical act and euthanasia. The only way to overcome such reluctance is to ensure flawless accompaniment, associating sedation and appropriate comfort care with a clear explanation (with relatives but also caregivers) of the rationale and implications of this type of decision. All teams dealing with this type of situation must have thoroughly thought through the medical, legal and ethical considerations involved in making this difficult decision.

Comparing responses to different selenium sources and dosages in laying hens.

Developing new sources of organic Se has potential benefit for animal production and human nutrition via animal-based foods enriched in Se. The objectives of this trial were to compare L-selenomethionine with another organic Se source, Se-enriched yeast (SelPlex 2300), and sodium selenite, an inorganic Se source, against a commercial control diet. The effect of source and the dosage of Se supplementation on Se in eggs and blood variables was investigated. Ten treatments were used with 18 laying hens per group. In addition to the control diet, the control diet was supplemented with L-selenomethionine, Se-enriched yeast, or sodium selenite at 0.1, 0.3, or 0.5 mg/kg of Se. The feeding trial lasted 8 wk. Birds in the different treatment groups all showed good performance. At d 0 and 56, Se and glutathione peroxidase (GPx) were analyzed in 10 blood samples per group. After supplementing the diets for 56 d, significantly higher Se levels in serum and egg contents were reached for the Se-supplemented groups compared with the control. Supplementing 0.3 and 0.5 mg/kg of L-selenomethionine or Se-enriched yeast instead of 0.1 mg/kg significantly increased the serum Se levels, whereas no significant increase was found for sodium selenite. No effect of Se source or dosage was observed on serum GPx levels. Selenium in eggs was significantly affected by dosage and source of Se. The Se supplementation level in the feed was reflected in the eggs, with the highest and lowest values for 0.5 and 0.1 mg/kg, respectively, and values in between for the 0.3 mg/kg supplementation level. A dose response was most pronounced for L-selenomethionine, followed by Se-enriched yeast, and was least when Se was added as sodium selenite. It can be concluded that Se from organic sources was more bioavailable than the inorganic Se source as evidenced by blood and egg Se levels. Within the organic Se sources, L-selenomethionine showed higher Se transfer to eggs than Se-enriched yeast.

Effect of the ratio of dietary n-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid on broiler breeder performance, egg quality, and yolk fatty acid composition at different breeder ages.

When added to the feed of broiler breeder hens, dietary polyunsaturated fatty acids (FA) can be incorporated into the yolk and therefore become available to the progeny during their early development. The mechanism involved in lipid metabolism and deposition in the egg may be influenced by breeder age. Before the effect of an elevated concentration of certain polyunsaturated FA on the embryo can be investigated, the effect at breeder level and egg quality must be further assessed. The aim of the present experiment was to evaluate the effects of dietary n-6/n-3 ratios and dietary eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) ratios, provided to broiler breeder hens, in terms of their zoo technical performance, egg quality, and yolk FA composition. Starting at 6 wk of age, 640 Ross-308 broiler breeder hens were fed 1 of 4 different diets. The control diet was a basal diet, rich in n-6 FA. The 3 other diets were enriched in n-3 FA, formulated to obtain a different EPA/DHA ratio of 1/1 (EPA = DHA), 1/2 (DHA), or 2/1 (EPA). In fact, after analysis the EPA/DHA ratio was 0.8, 0.4, or 2.1, respectively. Dietary EPA and DHA addition did not affect the performance of the breeder hens, except for egg weight. Egg weight was lower (P < 0.001) for all n-3 treatments. Dietary EPA improved number of eggs laid in the first 2 wk of the production cycle (P = 0.029). The absolute and relative yolk weight of eggs laid by EPA = DHA fed hens was lowest (P = 0.004 and P = 0.025, respectively). The EPA and DHA concentrations in the yolk were highly dependent on dietary EPA and DHA concentrations with a regression coefficient equal to 0.89. It can be concluded that dietary EPA and DHA can be incorporated in the breeder egg yolk to become available for the developing embryo, without compromising the performance and egg quality of the flock.

Can the use of coccidiostats in poultry breeding lead to residues in vegetables? An experimental study.

The aim of this study was to provide information on the dietary exposure of the European public to coccidiostats via vegetable consumption. Five groups of poultry followed a three-phase feeding schedule with feed containing the maximum allowed level of a coccidiostat: monensin, lasalocid A, salinomycin, diclazuril, and nicarbazin/narasin, plus one control group. Vegetables were cultivated on soil amended with manure (10 g of fresh weight/kg of soil) from the treated poultry. To mimic a worst-case scenario, vegetables were also grown on soil spiked with coccidiostats. For each vegetable/treatment combination, samples were harvested, freeze-dried, and analyzed using a validated liquid chromatography-tandem mass spectrometry method. Analysis of the vegetables demonstrated that these plants are capable of taking up these coccidiostats from the soil. However, the results indicate that these low incorporation levels, coupled with food consumption data and acceptable daily intakes, are unlikely to pose a direct threat to public health.