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Animal agriculture is facing substantial challenges from a steep projected increase in global demand for high quality animal protein and the need to adapt to higher temperature due to climate change. Indeed, with predictions that the world human population will increase to between 9 and 10 billion, United Nations Food and Agriculture Organization (FAO) estimates that by 2050 there will be increased demand for meat and egg protein by 73% and dairy prod-ucts by 58% over 2011 levels.
Editorial Feed Efficiency: A Key Production Trait and * *Corresponding author A Global Challenge Sami Dridi, PhD, HDR Associate Professor Avian Endocrinology and Molecular * Genetics Sami Dridi*, Nicholas Anthony, Byung-Whi Kong and Walter Bottje Center of Excellence for Poultry Science University of Arkansas 1260 W. Maple Street Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, Fayetteville AR 72701, USA USA Tel. (479)-575-2583 Fax: (479)-575-7139 E-mail: dridi@uark.edu Animal agriculture is facing substantial challenges from a steep projected increase in Volume 1 : Issue 3 global demand for high quality animal protein and the need to adapt to higher temperature due Article Ref. #: 1000AFTNSOJ1e004 to climate change. Indeed, with predictions that the world human population will increase to between 9 and 10 billion, United Nations Food and Agriculture Organization (FAO) estimates that by 2050 there will be increased demand for meat and egg protein by 73% and dairy prod- Article History th ucts by 58% over 2011 levels. Meeting the expected growth in global demand for high quality Received: June 26 , 2015 th animal protein will be very strenuous, especially under environmental temperature constraints Accepted: June 29 , 2015 th due to climate change and increased feed cost.
Published: June 30 , 2015 Large, abrupt, and widespread extreme heat waves have occurred repeatedly in the Citation past2 and resulted in estimated total annual economic loss to the US livestock production indus- Dridi S, Anthony N, Kong BW, try of $1.69 to 2.36 billion.3 More intense and frequent heat waves are predicted to increase for Bottje W. Feed efficiency: A key 4 the next century. Thus, there is a critical need for extensive applied and basic research efforts production trait and a global chal- to improve animal adaptability and tolerance to high ambient temperature and to maximize lenge. Adv Food Technol Nutr Sci Open J. 2015; 1(3): e11-e13. their productivity. Our research is devoted, using top-down/bottom-up approaches and mul- doi: 10.17140/AFTNSOJ-1-e004 tidisciplinary area ranging from integrative physiology and genetics to molecular and cellular biology, to understanding the molecular mechanisms that regulate energy homeostasis and feed efficiency in avian species as well as the basis of their response to environmental stress. Although it is moderately heritable, Feed Efficiency (FE) that defines the animal’s ability to convert feed into body weight, is a trait of vital importance for maintaining sustain- able agriculture. Two parameters are widely used to assess FE in chickens and in livestock: 1) Feed Conversion Ratio (FCR) that is defined as the amount of feed consumed per unit of weight gain5 and 2) Residual feed consumption or intake (RFC or RFI) which is the variation between animal’s actual and expected feed intake based on the estimated requirement for maintenance and growth/production.6 Genetic selection based on these parameters has made spectacular progress in meat production traits. For instance, as seen in Figure 1, under optimal husbandry conditions, body weight and breast yield have dramatically increased however FCR decreased. The selection methods however have been applied without knowledge of the fundamental mo- lecular mechanism changes that might be induced by the selection. Associated with these suc- cesses (increased muscle yield and high growth rate) there have been a number of undesirable changes in modern chickens such as muscle disorders (muscle myopathy, white striping), heart failure syndrome, ascites, lameness and fat deposition. Thus, a deep molecular and mechanistic understanding of traits of breeding interest may help to avoid the above mentioned unfavour- able consequences.
Copyright ©2015 Dridi S. This is an open ac- Our group has developed several avian (chicken and quail) genetic populations de- cess article distributed under the signed to attack specific (patho) physiological and environmental challenges facing the modern Creative Commons Attribution 4.0 poultry industry. As the regulation of energy homeostasis (energy intake and expenditure) and International License (CC BY 4.0), which permits unrestricted use, the stress response are coupled physiological processes,8 we have unique experimental models distribution, and reproduction in including quails that were divergently selected for high or low feed efficiency and for sensitiv- any medium, provided the original 9 ity or resistance to stress. As the hypothalamus, which contains the satiety and hunger centers, work is properly cited.
plays a crucial role in the regulation of body energy balance, we determined the feeding-
sea-level changes. Science. 2005; 310: 456-460. doi: 10.1126/ + + tion (R+). For the same body weight and egg production, the R+ science.1114613 - chickens consume 40% more feed than their counterparts R- lines.11 We identified several feeding-related hypothalamic key 3. St-Pierre NR, Cobanov B, Schnitkey G. Economic losses genes that are differentially expressed between the two lines that from heat stress by US livestock industries. J Dairy Sci. 2003; might explain the difference in feed intake.12 We also identified 86: E52-E77. doi: 10.3168/jds.S0022-0302(03)74040-5 avian mitochondrial uncoupling protein and found that it was + - highly expressed in the muscle of R+ compared to R- chicken 4. Mora C, Frazier AG, Longman RJ, et al. The projected timing + suggesting that the R+ chickens dissipate energy as heat and they of climate departure from recent variability. Nature. 2013; 502: are thereby inefficient.13 Our previous studies have also revealed 183-187. doi: 10.1038/nature12540 a link between mitochondrial bioenergetics and dynamics and FE in broiler chickens. Low FE birds exhibited lower mitochon- 5. Willems OW, Miller SP, Wood BJ. Aspects of selection for drial electron transport chain coupling and higher hydrogen feed efficiency in meat producing poultry. Worlds Poult Sci J.
peroxide compared to high FE counterparts.14 Interestingly, we 2013; 69: 77-88. doi: 10.1017/S004393391300007X recently found that the orexigenic peptide, orexin, was highly expressed in chicken muscle and orexin treatment altered mito- 6. Aggrey SE, Karnuah AB, Sebastian B, Anthony NB. Genetic chondrial biogenesis, bioenergetics and dynamics (fission and properties of feed efficiency parameters in meat-type chickens.
fusion) in avian muscle cells,15 however the role of orexin in Genet Sel Evol. 2010; 42: 25. doi: 10.1186/1297-9686-42-25 high and low feed efficiency warrants further studies.
7. Siegel PB. Evolution of the modern broiler and feed effi- With the new cutting edge techniques involving genom- ciency. Annu Rev anim Biosci. 2014; 2: 375-385. doi: 10.1146/ ics, proteomics, transcriptomics, mobilomics, microbiomics and annurev-animal-022513-114132 metabolomics we will have the potential to identify molecular signatures for feed efficiency and to solve the intervening puzzle 8. Valles A, Marti O, Garcia A, Armario A. Single exposure to between nutrients, genes, environment and performances. A per- stressors causes long-lasting, stress-dependent reduction of food sonalized nutrition approach based on identification, selection intake in rats. Am J Physiol Regul Integr Comp Physiol. 2000; and optimization of nutrients fine-tuned with animal genetic pro- 279: R1138-R1144.
files and animal’s capability to withstand environmental stress will improve performances, health and wellness.
9. Satterlee DG, Johnson WA. Selection of Japanese quail for contrasting blood corticosterone response to immobilization.
CONFLICTS OF INTEREST Poult Sci. 1988; 67: 25-32. doi: 10.3382/ps.0670025 The authors have declared that no conflicts of interest exist.
10. Sawchenko PE. Toward a new neurobiology of energy bal- ance, appetite, and obesity: The anatomists weigh in. J Comp