Psychological factors influencing consumer intentions to consume cultured meat, fish and dairy.

This study investigates the structure of factors that influence consumer intentions to both try and to consume cultured proteins, and their intentions to substitute vegan, vegetarian and omnivore diets with these alternative protein sources. Comprehensive survey data (N = 3862) was collected from three Nordic countries (Denmark, Finland, and Norway) and analysed using confirmatory factor analysis and structural equation modelling. Theoretically, this article draws from behavioural models of environmental psychology, identity theory, and attitude theory. Results indicate that beliefs about the necessity of an industry producing cultured proteins and impacts of cultured proteins on the global economy are significant predictors of consumer intentions. Moreover, participants who exhibited high levels of general and food innovativeness were more likely to express positive intentions to consume cultured proteins. Social norms influenced consumer intentions: Individuals surrounded by positive attitudes and intentions toward cultured proteins within their social networks were more inclined to want to consume these products. The predictor variables in the final model accounted for between 39% and 66% of the variance in the different cultured proteins related intentions. Understanding consumer intentions better can inform targeted communication strategies aimed at promoting the advantages of cultured proteins and facilitating its adoption.

The Longitudinal Association between Self-esteem and Depressive Symptoms in Adolescents: Separating between-person effects from within-person effects.

Many longitudinal studies have investigated whether self-esteem predicts depressive symptoms (vulnerability model) or the other way around (scar model) in adolescents. The most common method of analysis has been the Cross-lagged Panel Model (CLPM). The CLPM does not separate between-person effects from within-person effects, making it unclear whether the results from previous studies actually reflect the within-person effects, or whether they reflect differences between people. We investigated the associations between self-esteem and depressive symptoms at the within-person level, using Random Intercept Cross-Lagged Panel Models (RI-CLPM). To get an impression of the magnitude of possible differences between the RI-CLPM and CLPM, we compared the results of both models. We used data from three longitudinal adolescent samples (age range 7-18; Study 1: N=1,948; Study 2: N=1,455; Study 3: N=316). Intervals between the measurements were 1-1.5 years. Single-paper meta-analyses showed support for small within-person associations from self-esteem to depressive symptoms, but not the other way around, thus only providing some support for the vulnerability model. The cross-lagged associations in the aggregated RI-CLPM and CLPM showed similar effect sizes. Overall, our results show that over 1-1.5 year time intervals, low self-esteem may negatively influence depressive symptoms over time within adolescents, but only weakly so.

Associations among gait score, production data, abattoir registrations, and postmortem tibia measurements in broiler chickens.

Lameness and impaired walking ability in rapidly growing meat-type broiler chickens are major welfare issues that cause economic losses. This study analyzed the prevalence of impaired walking and its associations with production data, abattoir registrations, and postmortem tibia measurements in Norwegian broiler chickens. Gait score (GS) was used to assess walking ability in 59 different commercial broiler flocks (Ross 308) close to the slaughter d, 5,900 broilers in total, in 3 different geographical regions. In each flock, 100 arbitrary broilers were gait scored and 10 random broilers were culled to harvest tibias. Abattoir registrations on flock level were collected after slaughter. A total of 24.6% of the broilers had moderate to severe gait impairment. The broilers were sampled in 2 stages, first slaughterhouse/region, and then owner/flock. The final models showed that impaired gait is associated with first-week mortality (P < 0.05), region (P < 0.001), height of tibias mid-shaft (P < 0.05), and calcium content in the tibia ash (P < 0.05), and negatively associated with DOA (P < 0.05). The prevalence of impaired gait indicates that this is a common problem in the broiler industry in Norway, although the mean slaughter age is only 31 d and the maximum allowed animal density is relatively low. Impaired walking ability could not be predicted by the welfare indicators footpad lesion score, total on-farm mortality, and decreasing DOA prevalence. Further studies are needed to explore the relationship between first-week mortality and gait score.

In vitro digestion of purified ß-casein variants A(1), A(2), B, and I: effects on antioxidant and angiotensin-converting enzyme inhibitory capacity.

Genetic polymorphisms of bovine milk proteins affect the protein profile of the milk and, hence, certain technological properties, such as casein (CN) number and cheese yield. However, reports show that such polymorphisms may also affect the health-related properties of milk. Therefore, to gain insight into their digestion pattern and bioactive potential, ß-CN was purified from bovine milk originating from cows homozygous for the variants A(1), A(2), B, and I by a combination of cold storage, ultracentrifugation, and acid precipitation. The purity of the isolated ß-CN was determined by HPLC, variants were verified by mass spectrometry, and molar extinction coefficients at λ=280nm were determined. ß-Casein from each of the variants was subjected to in vitro digestion using pepsin and pancreatic enzymes. Antioxidant and angiotensin-converting enzyme (ACE) inhibitory capacities of the hydrolysates were assessed at 3 stages of digestion and related to that of the undigested samples. Neither molar extinction coefficients nor overall digestibility varied significantly between these 4 variants; however, clear differences in digestion pattern were indicated by gel electrophoresis. In particular, after 60min of pepsin followed by 5min of pancreatic enzyme digestion, one ≈4kDa peptide with the N-terminal sequence (106)H-K-E-M-P-F-P-K- was absent from ß-CN variant B. This is likely a result of the (122)Ser to (122)Arg substitution in variant B introducing a novel trypsin cleavage site, leading to the changed digestion pattern. All investigated ß-CN variants exhibited a significant increase in antioxidant capacity upon digestion, as measured by the Trolox-equivalent antioxidant capacity assay. After 60min of pepsin + 120min of pancreatic enzyme digestion, the accumulated increase in antioxidant capacity was ≈1.7-fold for the 4 ß-CN variants. The ACE inhibitory capacity was also significantly increased by digestion, with the B variant reaching the highest inhibitory capacity at the end of digestion (60min of pepsin + 120min of pancreatic enzymes), possibly because of the observed alternative digestion pattern. These results demonstrate that genetic polymorphisms affect the digestion pattern and bioactivity of milk proteins. Moreover, their capacity for radical scavenging and ACE inhibition is affected by digestion.

Validation of biomarkers for loin meat quality (M. longissimus) of pigs.

The aim of this study was to validate previously reported associations between microarray gene expression levels and pork quality traits using real-time PCR. Meat samples and meat quality data from 100 pigs were collected from a different pig breed to the one tested by microarray (Large White versus Pietrain) and a different country of origin (Denmark versus Germany). Ten genes (CARP, MB, CSRP3, TNNC1, VAPB, TNNI1, HSPB1, TNNT1, TIMP-1, RAD-like) were chosen from the original microarray study on the basis of the association between gene expression levels and the meat quality traits meat %, back fat, pH24, drip loss %, colour a*, colour b*, colour L*, WB-SF, SFA, MUFA, PUFA. Real-time PCR detection methods were developed for validation of all ten genes, confirming association with drip loss (two of two genes), ultimate pH (three of four genes), a* (redness) (two of six genes) and L*(lightness) (two of four genes). Furthermore, several new correlations for MUFA and PUFA were established due to additional meat quality trait information on fatty acid composition not available for the microarray study. Regression studies showed that the maximum explanation of the phenotypic variance of the meat quality traits was 50% for the ultimate pH trait using these ten genes only. Additional studies showed that the gene expression of several of the genes was correlated with each other. We conclude that the genes initially selected from the microarray study were robust, explaining variances of the genes for the meat quality traits.

Caffeic acid, naringenin and quercetin enhance glucose-stimulated insulin secretion and glucose sensitivity in INS-1E cells.

AIMS: Caffeic acid, naringenin and quercetin are naturally occurring phenolic compounds (PCs) present in many plants as secondary metabolites. The aim of this study was to investigate their effect on glucose-stimulated insulin secretion (GSIS) in INS-1E cells and to explore their effect on expression of genes involved in ß-cell survival and function under normoglycaemic and glucotoxic conditions. METHODS: For acute studies, INS-1E cells were grown in 11 mM glucose (72 h) and then incubated with the PCs (1 h) with 3.3/16.7 mM glucose; whereas, for chronic studies, the cells were grown in 11 mM glucose (72 h) with/without the PCs, and then incubated with 3.3/16.7 mM glucose (1 h); thereafter, GSIS was measured. For GSIS and gene expression studies (GES) under glucotoxic conditions, two sets of cells were grown in 11/25 mM glucose with/without the PCs (72 h): one was used for GES, using real time RT-PCR, and the other was exposed to 3.3/16.7 mM glucose, followed by measurement of GSIS. RESULTS: The study demonstrated that the PCs can enhance GSIS under hyperglycaemic and glucotoxic conditions in INS-1E cells. Moreover, these compounds can differentially, yet distinctly change the expression profile of genes [Glut2 (glucose transporter 2), Gck (glucokinase), Ins1 (insulin 1), Ins2, Beta2 (neurogenic differentiation protein 1), Pdx1 (pancreatic and duodenal homeobox protein 1), Akt1 (RAC-α serine/threonine-protein kinase encoding gene), Akt2 (RAC-ß serine/threonine-protein kinase encoding gene), Irs1 (insulin receptor substrate 1), Acc1 (acetyl CoA carboxylase 1), Bcl2 (ß-cell lymphoma 2 protein), Bax (Bcl-2 associated X protein), Casp3 (Caspase 3), Hsp70 (heat shock protein 70), and Hsp90] involved in ß-cell stress, survival and function. CONCLUSION: The results indicate that the PCs tested enhance GSIS and glucose sensitivity in INS-1E cells. They also modulate gene expression profiles to improve ß-cell survival and function during glucotoxicity.

Novel aspects of health promoting compounds in meat.

Meat is an integral part of the human diet. Besides essential amino acids and nutritive factors of high quality and availability, meat provides often overlooked components of importance for human health. These are amino acids and bioactive compounds that may be very important in i) preventing muscle wasting diseases, such as in sarcopenia, ii) reducing food and caloric intake to prevent metabolic syndrome, iii) blood pressure homeostasis via ACE-inhibitory components from connective tissue, and iv) maintaining functional gut environment through meat-derived nucleotides and nucleosides. In addition, meat could be an important source of phytanic acid, conjugated linoleic acids and antioxidants. Further, it becomes increasingly apparent that design of in vitro meat will be possible, and that this development may lead to improved health benefits from commercially viable and sustainable meat products.

Meat Science and Muscle Biology Symposium: in utero nutrition related to fetal development, postnatal performance, and meat quality of pork.

Intrauterine growth restriction (IUGR) occurs naturally in pigs and leads to low birth weight of piglets due to undernutrition caused by placental insufficiency. For 2 main reasons, low birth weight causes economic loss. First, low birth weight pigs have a greater mortality and increasing the litter size causes more low birth weight piglets within litters. Second, surviving low birth weight piglets have reduced performance (i.e., ADG, feed conversion rate, and percentage meat). To develop dietary strategies for preventing IUGR, knowledge of the biological basis of IUGR is required. Muscle fiber number, formed during myogenesis, is correlated positively with performance traits and has been shown in several studies to be reduced in low birth weight pigs. Postnatal muscle hypertrophy is due to satellite cell number per fiber at birth and their rate of proliferation as well as protein deposition (i.e., protein synthesis and degradation). Previous studies and some recent ones indicate that low birth weight littermates in mice are born with fewer satellite cells and studies on pigs show that the rate of satellite cell proliferation may vary within litters. Proteomics studies show that protein synthesis and degradation is downregulated in IUGR pigs and low birth weight pigs also produce meat with less tenderness. Alternative maternal feeding strategies to prevent IUGR have been examined. Increasing maternal global nutrition had no beneficial effect on performance and muscle growth traits in several studies. Feeding excess maternal dietary protein also did not influence muscle growth traits whereas moderately decreased maternal dietary protein may decrease muscle fiber number and performance. On the other hand, addition of L-carnitine to the maternal gestation or lactation diet may increase birth and weaning weights or the muscle fiber number, respectively, in low birth weight pig offspring. Finally, promising data have been obtained on reproductive traits in pigs after addition of functional AA, such as arginine and glutamine, to the gestational diet. Although much is known about the biological basis of IUGR, we still need to learn much more about the mode of action before maternal dietary strategies can be developed to prevent IUGR.

Differential susceptibility in youth: evidence that 5-HTTLPR x positive parenting is associated with positive affect 'for better and worse'.

Positive affect has been implicated in the phenomenological experience of various psychiatric disorders, vulnerability to develop psychopathology and overall socio-emotional functioning. However, developmental influences that may contribute to positive affect have been understudied. Here, we studied youths' 5-HTTLPR genotype and rearing environment (degree of positive and supportive parenting) to investigate the differential susceptibility hypothesis (DSH) that youth carrying short alleles of 5-HTTLPR would be more influenced and responsive to supportive and unsupportive parenting, and would exhibit higher and lower positive affect, respectively. Three independent studies tested this gene-environment interaction (GxE) in children and adolescents (age range 9-15 years; total N=1874). In study 1 (N=307; 54% girls), positive/supportive parenting was assessed via parent report, in study 2 (N=197; 58% girls) via coded observations of parent-child interactions in the laboratory and in study 3 (N=1370; 53% girls) via self report. Results from all the three studies showed that youth homozygous for the functional short allele of 5-HTTLPR were more responsive to parenting as environmental context in a 'for better and worse' manner. Specifically, the genetically susceptible youth (that is, S'S' group) who experienced unsupportive, non-positive parenting exhibited low levels of positive affect, whereas higher levels of positive affect were reported by genetically susceptible youth under supportive and positive parenting conditions. These GxE findings are consistent with the DSH and may inform etiological models and interventions in developmental psychopathology focused on positive emotion, parenting and genetic susceptibility.

NMR-based metabonomics reveals relationship between pre-slaughter exercise stress, the plasma metabolite profile at time of slaughter, and water-holding capacity in pigs.

Nuclear magnetic resonance (NMR)-based metabonomics was applied to investigate the effects of pre-slaughter exercise stress on the plasma metabolite profile at time of slaughter. The study included a total of 40 slaughter pigs, which were exposed to one of the following treatments: No pre-slaughter stress (control treatment), pre-slaughter exercise on a treadmill and subsequently 0, 1, or 3h rest prior to slaughter. NMR-based metabonomics revealed a clear difference in the plasma metabolite profile at time of slaughter between control pigs and pigs exercised without rest, which mainly could be ascribed to increased plasma lactate due to exercise. A resting period of 1 or 3h prior to slaughter reversed the stress-induced perturbations in the plasma metabolite profile. The plasma metabolite profile at time of slaughter was highly correlated with muscle temperature 1 min post-mortem, and a correlation to WHC was also demonstrated. Lactate was found to be the metabolite of importance for the association between the plasma metabolome and pH, temperature and WHC.

Rest before slaughter ameliorates pre-slaughter stress-induced increased drip loss but not stress-induced increase in the toughness of pork.

One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1-3h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs.

Dietary creatine monohydrate has no effect on pork quality of Danish crossbred pigs.

Creatine content in the muscle may delay postmortem lactate formation and postpone the pH decline, hence potentially improving the water-holding capacity (WHC) as shown in a previous study including purebred Duroc pigs, although the same study did not find any effect on meat from purebred Landrace pigs. In the present study Danish D(LY) crossbreeds were supplemented with 0 or 50g creatine monohydrate (CMH)/d for five days prior to the slaughter. CMH supplementation had no effect on meat quality indicators (pH and temperature), meat quality attributes (WHC and colour) or eating quality (juiciness and tenderness) of meat from the D(LY) crossbred pigs. As a consequence the D(LY) crossbreed was classified as a non-responder to CMH supplementation.

In vitro and in vivo studies of creatine monohydrate supplementation to Duroc and Landrace pigs.

Duroc and Landrace pigs as well as primary myotubes from these breeds were used to investigate mechanisms behind differences in their response to creatine monohydrate (CMH). Pigs were supplemented with 0, 12.5, 25 or 50g CMH/d for 5 days (n=10 per treatment and breed). Plasma levels of creatine increased dose-dependently in both breeds, while muscle-creatine phosphate content increased only in the Duroc pigs. (1)H NMR metabolic profiling showed a tendency towards clustering according to CMH supplementation only among Duroc pigs, revealing a stronger response compared to Landrace pigs. The abundance of insulin-like growth factor I and myostatin mRNA was decreased by CMH supplementation while that of type 1 IGF-receptor and creatine transporter was unaffected. Protein synthesis, increased in the myotubes from both breeds, indicating protein accretion, but no effect was observed on the mRNA abundance of IGF-I, type 1 IGF-receptor, myostatin or the creatine transporter in myotubes.

Hierarchical models for probabilistic dose-response assessment.

Probabilistic risk assessment is gaining acceptance as the most appropriate way to characterize and communicate uncertainties in estimates of human health risk and/or reference levels of exposure such as benchmark doses. Although probabilistic techniques are well established in the exposure-assessment component of the National Research Council's risk-assessment paradigm, they are less well developed in the dose-response-assessment component. This paper proposes the use of hierarchical statistical models as tools for implementing probabilistic dose-response assessments, in that such models provide a natural connection between the pharmacokinetic (PK) and pharmacodynamic (PD) components of dose-response models. The results show that incorporating internal dose information into dose-response assessments via the coupling of PK and PD models in a hierarchical structure can reduce the uncertainty in the dose-response assessment of risk. However, information on the mean of the internal dose distribution is sufficient; having information on the variance of internal dose does not affect the uncertainty in the resulting estimates of excess risks or benchmark doses. In addition, the complexity of a PK model of internal dose does not affect how the variability in risk is measured via the ultimate endpoint.

Creatine monohydrate and glucose supplementation to slow- and fast-growing chickens changes the postmortem pH in pectoralis major.

The energy status of the chicken at slaughter has a large impact on the development of pH postmortem and thus on color and water-holding capacity (WHC). Supplementation of creatine monohydrate and glucose (CMH+GLU) may increase the creatine content in the muscles before slaughter, thereby delaying the formation of lactic acid and postponing the pH decline. The objective of this study was to examine the impact of supplementing CMH+GLU in the drinking water within the last 48 h before slaughter on the pH decline, meat color, and WHC in the pectoralis major from 2 strains of Ross chickens. Forty Ross 308 (fast-growing) female chickens and 40 Ross 1972 (slow-growing) female chickens had free access to drinking water either supplemented with CMH (15 g/ L) and glucose (50 g/L) within the last 48 h before slaughter or without supplementation. All chickens were slaughtered at 42 or 43 d of age irrespective of weight. Temperature and pH were measured at 1 and 30 min and at 1, 3, 8, and 24 h postmortem. Also, WHC measured as drip loss and color were determined postmortem. The CMH+GLU supplementation decreased pH (P < 0.05) at all time points between 1 min and 8 h postmortem in both strains, whereas at 24 h postmortem only pH in Ross 308 chickens were decreased significantly upon supplementation. Lightness was significantly increased in the meat from Ross 308 but not from Ross 1972 chickens upon supplementation. This interaction was significant (P < 0.05). The redness of the meat was decreased upon supplementation (P < 0.05), although only significantly in Ross 1972. The pH was lower for Ross 1972 chickens at the early time points (P < 0.01) and also a higher drip loss (P < 0.05), lightness (P < 0.01), and redness (P < 0.001) were observed. Thus, there seems to be no beneficial effect of CMH+GLU supplementation on chicken meat quality on the basis of results from this experiment.

Dietary creatine monohydrate affects quality attributes of Duroc but not Landrace pork.

Increased creatine content in the muscle may delay post mortem lactate formation and postpone the pH decline, hence potentially improving the water-holding capacity (WHC). Duroc and Landrace pigs were supplemented with 0, 12.5, 25 or 50g creatine monohydrate (CMH)/d for 5 days prior to slaughter. Meat from Longissimus dorsi (LD) of Duroc pigs had a higher WHC and pH at all times, lower colour determinants; a* (redness), b* (yellowness), L* (lightness) and was more juicy compared to that of Landrace pigs. Furthermore, higher pH(2h), pH(24h) and decreased colour determinants were observed in carcass sides exposed to a faster cooling profile. Dietary supplementation with CMH increased the body weight gain of both breeds. However, only meat from Duroc pigs had higher pH(30min) and pH(45min) (at 50g CMH/d) and WHC, but reduced redness (reduced in both breeds) and juiciness when supplemented with CMH compared to non-supplemented controls.

Classification ensembles for unbalanced class sizes in predictive toxicology.

This paper investigates the effects of the ratio of positive-to-negative samples on the sensitivity, specificity, and concordance. When the class sizes in the training samples are not equal, the classification rule derived will favor the majority class and result in a low sensitivity on the minority class prediction. We propose an ensemble classification approach to adjust for differential class sizes in a binary classifier system. An ensemble classifier consists of a set of base classifiers; its prediction rule is based on a summary measure of individual classifications by the base classifiers. Two re-sampling methods, augmentation and abatement, are proposed to generate different bootstrap samples of equal class size to build the base classifiers. The augmentation method balances the two class sizes by bootstrapping additional samples from the minority class, whereas the abatement method balances the two class sizes by sampling only a subset of samples from the majority class. The proposed procedure is applied to a data set to predict estrogen receptor binding activity and to a data set to predict animal liver carcinogenicity using SAR (structure-activity relationship) models as base classifiers. The abatement method appears to perform well in balancing sensitivity and specificity.

Water-holding capacity in chicken breast muscle is enhanced by pyruvate and reduced by creatine supplements.

In commercial production, chickens are subjected to feed withdrawal prior to slaughter and exposed to stress during transport and handling of the animals at the slaughterhouse; this causes plasma glucose and glycogen stores in liver and muscle to decrease, which has a negative impact on meat quality. The aim of the present study was to investigate how supplementation of the energy complements creatine and pyruvate during the fasting period would affect postmortem pH decrease, water-holding capacity, and color of the meat. Female Ross 208 broilers were supplemented with glucose combined with either pyruvate or creatine via the drinking water for 18 or 42 h prior to slaughter, i.e., before and throughout the fasting period. Chickens were slaughtered at 42 or 43 d of age. Temperature and pH were measured at 1, 10, 30, and 45 min and 1, 2, 4, 8, and 12 h postmortem. The results showed that the pyruvate and glucose supplementation increased the pH at 45 min postmortem by 0.25 units and decreased drip loss of musculus pectoralis major (PM) by 50 to 65% in chickens supplemented for 42 h. The creatine and glucose supplementation reduced pH at 3 and 4 h postmortem by 0.32 to 0.42 units, increased the lightness (L*) by 2.3 to 5.6 units, and increased drip loss by 51 to 137% in the PM of chickens supplemented for 18 and 42 h. Pyruvate and glucose supplementation thus appear beneficial but whether this is concomitant with an overall improvement in meat quality remains to be determined.

Ascorbic acid, alpha-tocopherol, and oregano supplements reduce stress-induced deterioration of chicken meat quality.

In order to ameliorate a negative effect of stress on meat quality characteristics, chickens were fed a diet supplemented with a combination of ascorbic acid (1,000 ppm) and alpha-tocopherol (200 ppm) or oregano (3%), which has a high content of antioxidants. Chickens were slaughtered by cervical dislocation in the stable (no stress) or after transport and electrical stunning at the slaughter plant (stress). Activities of antioxidative enzymes (catalase, superoxide dismutase, and glutathion peroxidase) in pectoralis major (PM), iliotibialis (IL), and liver were unaffected by supplementation. However, erythrocyte stability, which is a more complex model system for determining oxidative status, increased with ascorbic acid-alpha-tocopherol supplementation and tended to increase after oregano supplementation. In nonstressed birds, this improved antioxidative status was reflected in decreased TBA-reactive substances (TBARS) in PM and liver of ascorbic acid-alpha-tocopherol-supplemented chickens and likewise in liver from oregano-supplemented chickens compared to that of nonstressed control birds. However, postmortem temperature, pH, and water-holding capacity were not affected by supplementation. Drip loss from oregano-supplemented chickens showed increased protein oxidation in specific bands, but this did not relate to water-holding capacity or antioxidative status. When exposed to stress, the concentration of TBARS in the control animals increased in PM and IL. Ascorbic acid-alpha-tocopherol supplementation protected IL, and oregano supplementation protected PM from stress-induced increases in TBARS. This differential effect between muscles may indicate differences in protection mechanisms. In conclusion, ascorbic acid-alpha-tocopherol and oregano supplements to chickens protect against stress-induced increase in TBARS, in different muscles.

Feed and strain effects on the use of outdoor areas by broilers.

1. The use of outdoor areas by two broiler strains, known to have different growth rates and with access to either moderate (M) or low (L) energy feeds, was examined to assess the consequences for production, meat quality, health and welfare. 2. Sixteen groups of either Ross 208 (ROSS) or a Labresse cross (LAB) were fed either feed M or L. They were raised indoors until 42 d of age when groups of 102 birds were moved to outdoor houses with free access to an outdoor area. 3. The number of chickens standing and lying, respectively, in each of 5 zones in the outdoor area were recorded at intervals throughout the outdoor growth period until slaughter at 84 d of age. Production variables were measured, and gait, feather condition, litter quality, and dermal lesions on foot-pads and hocks were scored together with objective meat quality measures. 4. Both strains showed a diurnal rhythm with most birds observed outside around sunrise and before sunset. Feed and strain both affected the distribution of the birds on the outdoor area, with more birds on feed M than L observed outside, and with more LAB birds outside and using more of the outdoor area than ROSS. This was reflected in some of the carcase and meat quality measures. Feather pecking and cannibalism only occurred in LAB. 5. ROSS was found to have a faster growth rate, poorer litter quality, more dermal lesions and impaired mobility, reflected in low usage of outdoor area and poor gait score compared with LAB. 6. This together with the presence of pectoral myopathies make ROSS unsuitable for 12 week growth in free range production systems. The occurrence of feather pecking and cannibalism in LAB make this particular Labresse cross questionable for meat-type poultry production.