Mitigating the detrimental effects of heat stress in poultry through thermal conditioning and nutritional manipulation.

The poultry industry faces several obstacles and challenges, including the changes in global temperature, increase in the per capita demand for meat and eggs, and the emergence and spread of various diseases. Among these, environmental challenges are one of the most severe hurdles impacting the growth and productivity of poultry. In particular, the increasing frequency and severity of heat waves over the past few years represent a major challenge, and this is expected to worsen in the coming decades. Chickens are highly susceptible to high ambient temperatures (thermal stress), which negatively affect their growth and productivity, leading to enormous economic losses. In the light of global warming, these losses are expected to increase in the near future. Specifically, the worsening of climate change and the rise in global temperatures have augmented the adverse effects of heat on poultry production worldwide. At present, the world population is approximately 7.9 billion, and it has been predicted to reach 9.3 billion by 2050 and approximately 11 billion by 2100, implying a great demand for protein supply; therefore, strategies to mitigate future poultry challenges must be urgently devised. To date, several mitigation measures have been adopted to minimize the negative effects of heat stress in poultry. Of these, thermal acclimation at the postnatal stage or throughout the embryonic stages has been explored as a promising approach; however, for large-scale application, this approach warrants further investigation to determine the suitable temperature and poultry age. Moreover, molecular mechanisms governing thermal conditioning are poorly understood. To this end, we sought to expand our knowledge of thermal conditioning in poultry, which may serve as a valuable reference to improve the thermotolerance of chickens via nutritional management and vitagene regulation. Vitagenes regulate the responses of poultry to diverse stresses. In recent years, nutritionists have paid close attention to bioactive compounds such as resveratrol, curcumin, and quercetin administered alone or in combination. These compounds activate vitagenes and other regulators of the antioxidant defense system, such as nuclear factor-erythroid 2-related factor 2. Overall, thermal conditioning may be an effective strategy to mitigate the negative effects of heat stress. In this context, the present review synthesizes information on the adverse impacts of thermal stress, elucidating the molecular mechanisms underlying thermal conditioning and its effects on the acquisition of tolerance to acute heat stress in later life. Finally, the role of some polyphenolic compounds, such as resveratrol, curcumin, and quercetin, in attenuating heat stress through the activation of the antioxidant defense system in poultry are discussed.

Accuracy of breeding values for production traits in turkeys (Meleagris gallopavo) using recursive models with or without genomics.

BACKGROUND: Knowledge about potential functional relationships among traits of interest offers a unique opportunity to understand causal mechanisms and to optimize breeding goals, management practices, and prediction accuracy. In this study, we inferred the phenotypic causal networks among five traits in a turkey population and assessed the effect of the use of such causal structures on the accuracy of predictions of breeding values. METHODS: Phenotypic data on feed conversion ratio, residual feed intake, body weight, breast meat yield, and walking score in addition to genotype data from a commercial breeding population were used. Causal links between the traits were detected using the inductive causation algorithm based on the joint distribution of genetic effects obtained from a standard Bayesian multiple trait model. Then, a structural equation model was implemented to infer the magnitude of causal structure coefficients among the phenotypes. Accuracies of predictions of breeding values derived using pedigree- and blending-based multiple trait models were compared to those obtained with the pedigree- and blending-based structural equation models. RESULTS: In contrast to the two unconditioned traits (i.e., feed conversion ratio and breast meat yield) in the causal structures, the three conditioned traits (i.e., residual feed intake, body weight, and walking score) showed noticeable changes in estimates of genetic and residual variances between the structural equation model and the multiple trait model. The analysis revealed interesting functional associations and indirect genetic effects. For example, the structural coefficient for the path from body weight to walking score indicated that a 1-unit genetic improvement in body weight is expected to result in a 0.27-unit decline in walking score. Both structural equation models outperformed their counterpart multiple trait models for the conditioned traits. Applying the causal structures led to an increase in accuracy of estimated breeding values of approximately 7, 6, and 20% for residual feed intake, body weight, and walking score, respectively, and different rankings of selection candidates for the conditioned traits. CONCLUSIONS: Our results suggest that structural equation models can improve genetic selection decisions and increase the prediction accuracy of breeding values of selection candidates. The identified causal relationships between the studied traits should be carefully considered in future turkey breeding programs.

Identification of QTL regions and candidate genes for growth and feed efficiency in broilers.

BACKGROUND: Feed accounts for about 70% of the total cost of poultry meat production. Residual feed intake (RFI) has become the preferred measure of feed efficiency because it is phenotypically independent of growth rate and body weight. In this study, our aim was to estimate genetic parameters and identify quantitative trait loci (QTL) for feed efficiency in 3314 purebred broilers using a genome-wide association study. Broilers were genotyped using a custom 55 K single nucleotide polymorphism (SNP) array. RESULTS: Estimates of genomic heritability for seven growth and feed efficiency traits, including body weight at 28 days of age (BW28), BW42, average daily feed intake (ADFI), RFI, and RFI adjusted for weight of abdominal fat (RFIa), ranged from 0.12 to 0.26. Eleven genome-wide significant SNPs and 15 suggestively significant SNPs were detected, of which 19 clustered around two genomic regions. A region on chromosome 16 (2.34-2.66 Mb) was associated with both BW28 and BW42, and the most significant SNP in this region, AX_101003762, accounted for 7.6% of the genetic variance of BW28. The other region, on chromosome 1 (91.27-92.43 Mb) was associated with RFI and ADFI, and contains the NSUN3 and EPHA6 as candidate genes. The most significant SNP in this region, AX_172588157, accounted for 4.4% of the genetic variance of RFI. In addition, a genomic region containing the gene AGK on chromosome 1 was found to be associated with RFIa. The NSUN3 and AGK genes were found to be differentially expressed in breast muscle, thigh muscle, and abdominal fat between male broilers with high and low RFI. CONCLUSIONS: We identified QTL regions for BW28 and BW42 (spanning 0.32 Mb) and RFI (spanning 1.16 Mb). The NSUN3, EPHA6, and AGK were identified as the most likely candidate genes for these QTL. These genes are involved in mitochondrial function and behavioral regulation. These results contribute to the identification of candidate genes and variants for growth and feed efficiency in poultry.

Physio-biochemical, antioxidant and oxidative stability of Turkey meat-fed diet incorporated with different level of organic chromium.

The aim of this study was to evaluate the effects of organic chromium (Cr) on physico-biochemical and oxidative stability of turkey meat. Ninety-six (16th weeks) male turkeys were distributed into 16 groups (4 diet × 4 replicates × 6 birds each). Four dietary treatments (T1, T2, T3 and T4) were formulated with supplementation of 0.0, 250, 500 and 750 µg Cr/kg diets, respectively. Cholesterol and fat contents in meat reduced (p < 0.05) in T4 (750 µg Cr/kg) but no difference was observed in pH and drip loss. No significant effect was recorded on water holding capacity (WHC) and extract release volume (ERV) of fresh meat but the effect (p < 0.05) was observed on WHC and ERV in refrigerated meat. No significant difference was observed in DPPH (1, 1-diphenyl-2-picrylhydrazy) and ABTS (2, 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) of fresh breast and thigh meat but effect (p < 0.05) was noticed in refrigerated meat of turkey fed T4. Lipid oxidation (free fatty acids and Thio-barbituric acid reactive substances-TBARS) were improved in fresh as well as refrigerated meat from birds fed diet supplemented with 750 µg Cr/kg (T4). Whereas, peroxide value was improved (p < 0.05) only in refrigerated meat. Thus, it may be concluded that inclusion of Cr at 750 µg/kg diet with basal diet improved in desirable physio-biochemical properties, antioxidant and oxidative stability of male turkey meat under cold chain.

Effects of gingerols-rich extract of ginger on growth performance, serum metabolites, meat quality and antioxidant activity of heat-stressed broilers.

In order to investigate the effects of dietary ginger extract (GE) enriched in gingerols on broilers under heat stress (HS) from 21 to 42 days of age, a total of 144 Ross 308 male broilers were randomly allocated to three groups with six replicates of eight broilers per replicate. Broilers in the control group were raised at 22 °C and fed a basal diet, and broilers in the other two groups were raised under cyclic HS (34 °C from 9:00 to 17:00 and at 22 °C for the rest of the time) and fed the basal diet with or without 1000 mg/kg GE. Supplementation of GE improved (P < 0.05) final body weight, average daily gain and feed conversion ratio of broilers under HS, and tended (P < 0.1) to increase breast muscle yield. The alterations of serum total protein, albumin, total cholesterol levels and aspartate aminotransferase activity under HS were reversed (P < 0.05) by GE, which also decreased (P < 0.05) serum triglyceride level and alanine aminotransferase activity. The decreased redness (a* value) and increased drip loss of breast muscle induced by HS were restored (P < 0.05) by GE. Moreover, GE supplementation increased (P < 0.05) total antioxidant capacity and decreased (P < 0.05) malondialdehyde content in liver and breast muscle, and increased (P < 0.05) glutathione peroxidase activity in serum and breast muscle. In conclusion, dietary GE supplementation restored growth performance, serum metabolites and meat quality of broilers under HS possibly by improving antioxidant activity.

Fabrication of olive leaf extract and hazelnut skin incorporated films to improve the quality of nuggets during refrigerated and deep freeze storage.

1. Olive leaf extract (OLE) and hazelnut skin (HS), which are known to have good antioxidant activity, were added into chicken nuggets in different ways. In the first method, the nuggets were coated with sodium alginate-calcium chloride-based coatings containing OLE and HS. In the second method, OLE and HS were directly added into the nugget patties. Nuggets that did not contain any additive (C1) and the samples prepared with the coating solution that did not include any additives (C2) were assigned as controls.2. Nuggets were stored at two different temperatures, either in a refrigerator (4°C) or in a deep freezer (-18°C) for 21 days and 90 days respectively. Moisture content (%), pH, antioxidant status (TBARS), colour and microbial count (total mesophilic and psychrophilic aerobic bacteria) analyses were carried out during storage.3. At the end of refrigerator storage (day 21), TBARS values for samples in which OLE and HS were directly added were found to be lower than those with OLE and HS coatings (P < 0.05). Total number of mesophilic and psychrophilic bacteria were found to be the lowest in the treatment in which HS was directly incorporated into nugget patty (P < 0.05).4. For frozen samples, application of a coating containing OLE and HS and direct addition of HS into patties were found to be effective in reducing lipid oxidation. No microbial growth was determined in most of the samples stored in the deep freezer.

Alpha-cyclodextrin as a new functional ingredient in low-fat chicken frankfurter.

1. The current consumer preference for healthier meat products is associated with less additives in manufacturing (so-called 'clean-label') or the addition of non-meat ingredients with functional properties, recognised as improving specific technological properties in meat products.2. This study evaluated the effect of the addition of alpha-cyclodextrin and wheat fibre to low-fat chicken frankfurters containing 35% mechanically deboned chicken meat on the technological and sensorial properties during refrigerated storage.3. The results showed that the addition of dietary fibres (alpha-cyclodextrin and wheat fibre) in low-fat chicken frankfurters improved emulsion stability, hardness, chewiness and reduced cohesiveness.4. Alpha-cyclodextrin helped the retention of fat globules in the microstructure and affected colour in the sensorial evaluation.5. The use of alpha-cyclodextrin, in combination with wheat fibre, as a new ingredient to substitute fat in emulsified meat products containing mechanically deboned chicken, improved emulsion stability and texture.6. Alpha-cyclodextrin and wheat fibre were effective in contributing to fat reduction without affecting the sensory properties of the product.

Global restriction of using antibiotic growth promoters and alternative strategies in poultry production.

A growing global concern of antibiotic use in poultry diets due to its potential adverse effects on birds and human health, food safety and the environment has led to a complete ban or restricted use in some countries, and, at the same time, expanding options for the use of alternative feed additives. Multiple, rather than a single additive may replace antibiotic growth promoters (AGPs) in poultry. Blending of feeding additives and hygienic farm management, vaccination and biosecurity may help achieve good intestinal health, stabilise enteric ecosystems and result in sustainable and cost effective production performance of birds. Moreover, controlling unsolicited ingredients at the production level must have the support of different markets responsible for the supply of safe and quality poultry products for consumers. This requires the further increase and diversification of value added poultry products and the expansion of their markets through strategic planning and gradual limitation of live bird markets. More research is warranted in order to explore suitable, reliable and cost effective alternatives to AGPs for commercial use, and strategic poultry value chain development.

Heat stress in poultry production: Mitigation strategies to overcome the future challenges facing the global poultry industry.

Worldwide, the effect of climatic variations has become a great challenge in poultry production. As global climate is changing, it alters the environmental temperatures, precipitation patterns and atmospheric carbon dioxide. Poultry farming mainly depends on climatic conditions such as temperature and humidity. Several factors can be involved but heat stress is one of most important environmental factor influencing a wide range of chickens performances including reduced feed intake which, in turn, affects growth rate, body weight, meat quality, egg quality, egg production, semen quality and fertility; these negative influences result in great economic losses. Heat stress associated food safety issues have gained special importance due to public awareness and an abundance of available scientific information. Environmental modifications (early heat conditioning, open sheds and cooling systems) and nutritional strategies (early feed restriction, electrolyte, vitamin and mineral balance) cannot satisfy the special needs of stressed poultry. Therefore, there exists a crucial need to explore effective strategies including genetic markers to enhance thermo-tolerance and productivity of poultry birds in hot regions of the world.

Deciphering mechanisms underlying the genetic variation of general production and liver quality traits in the overfed mule duck by pQTL analyses.

BACKGROUND: The aim of this study was to analyse the mechanisms that underlie phenotypic quantitative trait loci (QTL) in overfed mule ducks by identifying co-localized proteomic QTL (pQTL). The QTL design consisted of three families of common ducks that were progeny-tested by using 294 male mule ducks. This population of common ducks was genotyped using a genetic map that included 334 genetic markers located across 28 APL chromosomes (APL for Anas platyrhynchos). Mule ducks were phenotyped for 49 traits related to growth, metabolism, overfeeding ability and meat and fatty liver quality, and 326 soluble fatty liver proteins were quantified. RESULTS: One hundred and seventy-six pQTL and 80 phenotypic QTL were detected at the 5% chromosome-wide significance threshold. The great majority of the identified pQTL were trans-acting and localized on a chromosome other than that carrying the coding gene. The most significant pQTL (1% genome-wide significance) were found for alpha-enolase on APL18 and fatty acid synthase on APL24. Some proteins were associated with numerous pQTL (for example, 17 and 14 pQTL were detected for alpha-enolase and apolipoprotein A1, respectively) and pQTL hotspots were observed on some chromosomes (APL18, 24, 25 and 29). We detected 66 co-localized phenotypic QTL and pQTL for which the significance of the two-trait QTL (2t-QTL) analysis was higher than that of the strongest QTL using a single-trait approach. Among these, 16 2t-QTL were pleiotropic. For example, on APL15, melting rate and abundance of two alpha-enolase spots appeared to be impacted by a single locus that is involved in the glycolytic process. On APLZ, we identified a pleiotropic QTL that modified both the blood level of glucose at the beginning of the force-feeding period and the concentration of glutamate dehydrogenase, which, in humans, is involved in increased glucose absorption by the liver when the glutamate dehydrogenase 1 gene is mutated. CONCLUSIONS: We identified pleiotropic loci that affect metabolic pathways linked to glycolysis or lipogenesis, and in the end to fatty liver quality. Further investigation, via transcriptomics and metabolomics approaches, is required to confirm the biomarkers that were found to impact the genetic variability of these phenotypic traits.

Effect of oven cooking method on formation of heterocyclic amines and quality characteristics of chicken patties: steam-assisted hybrid oven versus convection ovens.

The aim of this study was to evaluate effect of steam-assisted hybrid oven cooking method in comparison with convection ovens (natural and forced) on quality characteristics (color, hardness, cooking loss, soluble protein content, fat retention, and formation of heterocyclic aromatic amines) of chicken patties. The cooking experiments of chicken patties (n = 648) were conducted at oven temperatures of 180, 210, and 240°C until 3 different end point temperatures (75, 90, and 100°C) were reached. Steam-assisted hybrid oven cooking enabled faster cooking than convection ovens and resulted in chicken patties having lower a* and higher L* value, lower hardness, lower fat, and soluble protein content (P < 0.05), and higher cooking loss than convection ovens. Steam-assisted hybrid oven could reduce the formation of heterocyclic aromatic amines that have mutagenic and carcinogenic effects on humans.

Free range and deep litter poultry production systems: effect on performance, carcass yield and meat composition of cockerel chickens.

This study was carried out on 150 cockerel chickens each of Harco Black and Novogen strains to determine their performance, carcass yield and meat composition on free range and deep litter production systems. The birds were brooded for 4 weeks and thereafter allotted to the different production systems for a period of 12 weeks. Each production system was allotted 150 chicks (75 chicks per strain) with three replicates of 25 chicks. The birds on deep litter production system were fed ad libitum while each bird on free range was fed 50 % of its daily feed requirement. On the 84 th day, a total of 36 birds were randomly selected for analysis of the carcass yield and meat composition. The data generated were subjected to a two-way analysis of variance in a 2 × 2 factorial experimental arrangement. Novogen strain consumed less feed (P < 0.05) on free range and had the best feed/gain (2.72). A higher (P < 0.05) shear force value (3.74 N) was obtained in the thigh muscle for birds on free range. The tibia proximal length and breadth, and tibia distal length and breadth were significantly (P < 0.05) affected by the production systems and strains. On free range, Harco black had more meat (85.69 g) than bone (18.07 g) in the breast while Novogen had the lowest meat/bone (2.38). Conclusively, Novogen strain should be raised on free range for a better performance in terms of feed/gain, but for higher meat composition, Harco black is a better strain.

Zoning and compartmentalisation as risk mitigation measures: an example from poultry production.

This paper discusses the application of compartmentalisation in the Thai commercial poultry industry. The concept was adopted to address Thailand's inability to export fresh poultry meat because of endemic avian influenza. Owing to the nature of compartmentalisation, implementation required a strong partnership between government and the private sector (the Thai poultry exporters). The paper describes the processes implemented to ensure that appropriate risk mitigation measures were in place and to guarantee the continued biosecurity of the compartments. Other Members of the World Organisation for Animal Health may be able to adapt the compartment system used in Thailand to their own similar situations and the formal international recognition of such systems would be beneficial.

Instrumental texture analysis of chicken patties prepared with broiler breast fillets exhibiting woody breast characteristics.

Potential applications of chicken meat with the woody breast (WB) condition in further processed products could provide processors with alternatives to deal with this meat quality problem. The objective of this study was to evaluate the effect of the use of broiler breast fillets at varying degrees of WB severity and proportions on instrumental texture characteristics of chicken patties. A total of 54 breast fillets were collected from broilers processed as per commercial practices, previously classified based on tactile evaluation in 3 WB categories (normal [NOR]; mild [MIL], and severe [SEV]). Instrumental compression analysis was performed to validate subjective scores. Nine treatments with 6 replicates of chicken patties were prepared: 100% NOR (T1), 67% NOR + 33% MIL (T2), 67% NOR + 33% SEV (T3), 33% NOR + 67% MIL (T4), 33% NOR + 67% SEV (T5), 100% MIL (T6), 67% MIL + 33% SEV (T7), 33% MIL + 67% SEV (T8), and 100% SEV (T9). Instrumental texture profile analysis along with cook loss, color, and dimensional changes was evaluated in cooked patties. Compared with normal samples and excluding treatments T2 and T4, hardness, springiness, and chewiness values of chicken patties decreased (P < 0.05) as WB severity increased in the meat incorporated into the formulation. Patties prepared using mixtures of MIL and SEV fillets (T7 and T8) including T9 had higher levels of cook loss (>26%, P < 0.05) accompanied by significant reductions in diameter (>16%, P < 0.05) and distinguishable color changes (ΔE∗ab > 2) than normal patties. These data suggest that the potential use of WB meat in chicken patties is associated with the degree of WB severity and the incorporation rate. The inclusion of WB fillets at high levels into this product is not recommended owing to their poor functionality. However, feasible mixtures of normal breast fillets with those affected by WB myopathy at relatively low proportions could be considered by processors as an alternative in commercial chicken patty formulations.

Effect of storage time on the quality of chicken sausages produced with fat replacement by collagen gel extracted from chicken feet.

The objective of this study was to evaluate the use of collagen gel extracted from chicken feet on chicken sausages during 42 d of refrigerated storage. Three chicken sausages were processed: standard (SS); replacing 50% fat with commercial collagen powder (SC); replacing 50% fat with chicken foot collagen gel (SG). Sausages were stored at 4°C and analyzed every 14 d, for proximate composition, fatty acid profile, thiobarbituric acid reactive substances (TBARS) number, antioxidant activity, electrophoresis, instrumental color, water holding capacity (WHC), texture profile analysis, and quantitative descriptive analysis. Sausages SC and SG had similar behavior to the standard in the sensorial parameters of appearance and color over 28 d of refrigerated storage. SG had the highest WHC (81.05%), the lowest TBARS value (0.38 mg MDA/kg), and the highest antioxidant activity in addition to having the best atherogenicity and thrombogenicity index compared with SC treatment, making collagen gel viable to replace fat and control the effects of lipid oxidation.

Effects of wheat fiber addition on emulsion and lipid/protein stabilities of an omega-3 fatty acid-fortified chicken surimi product.

Meat, except marine sources, is a highly nutritious food but generally lacks some healthy ingredients, such as omega-3 fatty acids (ω-3 FA) and dietary fiber. However, ω-3 FA and dietary fiber could be incorporated during the manufacture of surimi-like products. In our previous study, chicken surimi was successfully developed from spent-hen breast. Although there was no (P > 0.05) difference in water-holding capacity between wheat fiber and carrageenan, an increased (P < 0.05) flaxseed oil-holding capacity was observed in wheat fiber samples. Furthermore, an addition of 5% wheat fiber resulted in optimal emulsification capacity and less cooking loss at 4°C for 14 d and at -20°C for 60 d (P < 0.05). Because of the lower (P < 0.05) purge and centrifugation losses, thiol group content, and thiobarbituric acid reactive substance value than those formulated with more flaxseed oil, 12% flaxseed oil was an optimal level in chicken surimi with 5% wheat fiber. Scanning electron microscopy results also showed better emulsification of surimi batters with wheat fiber compared with those without wheat fiber, and meanwhile, the formulation with 5% wheat fiber could hold up to 12% flaxseed oil as well. To enhance flaxseed-oil addition, semi-manufactured chicken surimi batter was successfully fortified with a combination of 12% flaxseed oil and 5% wheat fiber. This surimi-like product with dietary fiber and ω-3 FA would fit the need in the current market regarding consumers' demands for high nutritional value and improved processing characteristics.

Modeling time to inactivation of Listeria monocytogenes in response to high pressure, sodium chloride, and sodium lactate.

A mathematical model was developed to predict time to inactivation (TTI) by high pressure processing of Listeria monocytogenes in a broth system (pH 6.3) as a function of pressure (450 to 700 MPa), inoculum level (2 to 6 log CFU/ml), sodium chloride (1 or 2%), and sodium lactate (0 or 2.5%) from a 4°C initial temperature. Ten L. monocytogenes isolates from various sources, including processed meats, were evaluated for pressure resistance. The five most resistant strains were used as a cocktail to determine TTI and for model validation. Complete inactivation of L. monocytogenes in all treatments was demonstrated with an enrichment method. The TTI increased with increasing inoculum level and decreasing pressure magnitude, from 1.5 min at 700 MPa and 2 log CFU/ml, to 15 min at 450 MPa and 6 log CFU/ml. Neither NaCl nor sodium lactate significantly influenced TTI. The model was validated with ready-to-eat, uncured, Australian retail poultry products, and with product specially made at a U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS)-inspected pilot plant in the United States. Data from the 210 individual product samples used for validation indicate that the model gives "fail-safe" predictions (58% with response as expected, 39% with no survivors where survivors expected, and only 3% with survivors where none were expected). This model can help manufacturers of refrigerated ready-to-eat meats establish effective processing criteria for the use of high pressure processing as a postlethality treatment for L. monocytogenes in accordance with FSIS regulations.

Combined chitosan-thyme treatments with modified atmosphere packaging on a ready-to-cook poultry product.

In the present study, natural antimicrobials chitosan and thyme, and their combination, were evaluated for their effect on the shelf life of a ready-to-cook (RTC) chicken-pepper kebab (skewer) stored under modified atmosphere packaging (MAP) conditions at 4 +/- 0.5 degrees C for 14 days. The following treatments were examined: control samples stored under aerobic packaging (A), samples stored under MAP (M), samples treated with 1.5% chitosan (vol/wt) and stored under MAP (M-CH), samples treated with 0.2% thyme essential oil (vol/wt) (M-T), and samples treated with 1.5% chitosan (vol/wt) and 0.2% thyme essential oil (vol/wt) and stored under MAP (M-CH-T). Treatment M-CH-T significantly affected aerobic plate counts and counts of lactic acid bacteria, Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, and yeasts and molds during the entire storage period. Similarly, lipid oxidation of the RTC product was retarded (M-CH-T treatment) during storage, whereas redness was maintained in M-T, M-CH, and M-CH-T samples. Based primarily on sensory data (taste attribute), M-CH and M-T treatments extended RTC product shelf life by 6 days, whereas M-CH-T treatment resulted in a product with a shelf life of 14 days that maintained acceptable sensory characteristics (shelf life of the control was 6 days).

[Application of risk assessment in process of standards establishment about campylobacter jejuni in chicken].

OBJECTIVE: According to risk assessment results of the Campylobacter jejuni in chicken of Chinese residents' dietary, from the point of the standard management, establish the feasible measures to reduce the risk. METHODS: Half-quantity risk assessment of Risk Ranger was used. RESULTS: Campylobacter jejuni usually could not reproduce in the processing environment or in the processed products of chicken. Currently, the risk of the likelihood that the urban people of our country have Campylobacter jejuni infections due to eating chicken was six times as that of the rural people. CONCLUSION: There is no need to set a limit level for Campylobacter jejuni in the standard of chicken products. Control in the feeding, processing and preparation before eating of chicken are the important measures in reducing the Campylobacter jejuni infections caused by chicken.

Dietary strategies to improve nutritional value, oxidative stability, and sensory properties of poultry products.

Consumers demand both safer and more nutritious food products exempt of non-natural origin preservatives or other food additives. In this frame, products with lower fat content and/or a higher ratio in unsaturated fatty acids, especially n-3 fatty acids, are desired because these lipids can help prevent the development of cardiovascular and inflammatory pathologies. The intake of meat products is of interest because they are an excellent source of vitamins and minerals. In addition, the shelf-life of meat products can be extended by the presence of natural antioxidants coming from different sources such as plant extracts. Therefore, different strategies have been studied to improve the nutritional value, oxidative stability, and sensory characteristics of meat products and eggs through different mineral and natural dietary supplements. In comparison to other strategies, dietary supplements present the advantage that first the living animals may efficiently distribute the compounds throughout the tissues and second, the dietary supplementation is safer because the resulting enriched meat products and eggs ensure tolerable amounts in humans. Poultry meats and eggs are widely consumed and their fatty acid profile and tocopherol content can be easily modified through different dietary strategies thus being excellent models to improve their nutritional value and oxidative stability.