Effect of dietary coarse corn inclusion on broiler live performance, litter characteristics, and ammonia emission

Can the broiler industry rely on results of existing life cycle assessment and environmental assessments studies to inform broilers' nutritional strategies?

The goal of this systematic review is to investigate the applicability of the results from existing life cycle analysis (LCA) and environmental assessments studies in informing nutritional strategies for environmentally sustainable poultry meat production. This paper reports on a Rapid Evidence Assessment (REA) of articles published between 2000 and 2020. The studies reviewed were conducted in developed countries including UK, France, Germany, Sweden, Norway, The Netherlands, Denmark, Belgium, Canada, and USA. All articles were written in English. The REA includes studies on LCA of differing strains of meat poultry and production systems, studies on poultry manure emission and studies on environmental assessments of plant-based feed ingredients. The review covered studies on soil carbon dynamics associated with plant-based ingredients. Web of Science, Scopus, and PubMed were used to obtain the 6,142 population articles. The multistage screening process resulted in 29 studies from which 15 studies included LCA while the rest 14 studies analyzed NH₃ emission of broilers. All studies based on LCA were descriptive and did not include replications. Only 12 studies assessed the effect of interventions to reduce NH₃ emission of broiler litter using replicated layout designs. It is concluded that the broiler industry in UK, EU, and North America cannot rely on results of existing LCA and environmental assessments studies to inform their nutritional strategy and poultry meat production due to a shortage of reliable in vivo data assessing interventions in controlled studies.

Liver transcriptome analysis reveals biological pathways and transcription factors in response to high ammonia exposure

Aim: Ammonia is a toxic gas that not only causes environmental pollution, but also is harmful to human health after inhalation. Liver is an important detoxification organ that can convert external or metabolized toxic substances into nontoxic substances. However, the toxic effects of ammonia exposure on livers have not been well studied.Method: In this study, pigs were used as an animal model and were exposed to 80 ppm ammonia (8 h during 12 days), and then, RNA-seq were conducted to explore the key genes in response to high ammonia exposure in livers.Result: Gene set enrichment analysis (GSEA) showed that the genes associated with hypoxia, inflammatory response, and apoptosis were up-regulated in the ammonia group, but the genes associated with DNA replication, linoleic acid metabolism, and glycolysis were down-regulated. Totally, 556 differentially expressed genes (DEGs) including 54 genes that encode the transcription factors (TFs) were identified between the exposure and control groups. GO and KEGG pathway analysis suggested that these DEGs were involved in inflammatory response, oxidative stress, apoptosis, immune, and cell cycle. Furthermore, the TF-target interaction analysis showed that FOS, HIF-1α, JUNB, ATF3, REL, and KLF4 were important TFs in regulating the hepatic gene expression in response to high ammonia exposure.Conclusion: Altogether, our findings not only presented a comprehensive mRNA transcriptome profile of liver after high ammonia exposure, but also found some key genes and TFs that could be used to investigate the toxicity mechanism of high ammonia on livers.

Impacts of Air Velocity Treatments under Summer Condition: Part I—Heavy Broiler’s Surface Temperature Response

Simple Summary

The surface temperature variation of heavy broilers (42–61 d age) under heat stress is an important indicator of thermal comfort, but it is not well studied and reported yet. This study examined the variation of surface temperatures of broilers through two dynamic air velocity treatments under hot summer conditions. It was discovered that the surface temperatures varied over age, daytime, and environmental factors (air temperature, relative humidity, and temperature humidity index). A simple linear regression model to predict the surface temperature of heavy broilers was developed. The findings from this study will enhance knowledge to understand the broilers’ responses under heat stress, which will be helpful in providing necessary management decisions to create a comfortable thermal environment.

Abstract

Heavy broilers exposed to hot summer conditions experience fluctuations in surface temperatures due to heat stress, which leads to decreased performance. Maintaining a bird’s homeostasis depends on several environmental factors (temperature, relative humidity, and air velocity). It is important to understand the responses of birds to environmental factors and the amount of heat loss to the surrounding environment to create thermal comfort for the heavy broilers for improved performances and welfare. This study investigates the variation in surface temperatures of heavy broilers under high and low air velocity treatments. Daytime, age and bird location’s effect on the surface temperature variation was also examined. The experiment was carried out in the poultry engineering laboratory of North Carolina State University during summers of 2017, 2018, and 2019 as a part of a comprehensive study on the effectiveness of wind chill application to mitigate heat stress on heavy broilers. This live broiler heat stress experiment was conducted under two dynamic air velocity treatments (high and low) with three chambers per treatment and 44 birds per chamber. Surface temperatures of the birds were recorded periodically through the experimental treatment cycles (flocks, 35–61 d) with infrared thermography in the morning, noon, evening, and nighttime. The overall mean surface temperature of the broilers under two treatments was found to be 35.89 ± 2.37 °C. The variation in surface temperature happened due to air temperature, thermal index, air velocity, bird’s age, daytime, and position of birds inside the experimental chambers. The surface temperatures were found lower under high air velocity treatment and higher under low air velocity treatment. During the afternoon time, the broilers’ surface temperatures were higher than other times of the day. It was also found that the birds’ surface temperature increased with age and temperature humidity indices. Based upon the experimental data of five flocks, a simple linear regression model was developed to predict surface temperature from the birds’ age, thermal indices, and air velocity. It will help assess heavy broilers’ thermal comfort under heat stress, which is essential to provide a comfortable environment for them.