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Fernandes E, Raymundo A, Martins LL, Lordelo M, de Almeida AM. The Naked Neck Gene in the Domestic Chicken: A Genetic Strategy to Mitigate the Impact of Heat Stress in Poultry Production—A Review. Animals (Basel) 2023; 13:ani13061007. [PMID: 36978548 PMCID: PMC10044606 DOI: 10.3390/ani13061007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
The poultry sector is one of the most important food industries in the world. Poultry production generates high-value protein products (meat and eggs) that are produced efficiently without the need for large areas. In poultry production, especially in the tropics, environmental factors, such as temperature and humidity, play a major role. Heat stress (HS) causes behavioral, physical, and physiological changes in poultry, with severe financial impacts. Therefore, it is important to find strategies to minimize it. The naked neck (Na) is an autosomal, incompletely dominant gene. Compared with normal feathered birds, these animals are known for their ability to adapt, perform, and reproduce under hot and humid climate conditions. Due to the absence of feathers on the neck, these animals increase heat dissipation, alleviating adverse heat effects, especially on productive performance. Genetic improvement of heat tolerance may provide a low-cost solution, of particular interest for developing countries in the tropics. The focus of this review is to evaluate the impact of HS in poultry with a special emphasis on the advantages of using the Na gene.
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Durosaro SO, Iyasere OS, Ilori BM, Oyeniran VJ, Ozoje MO. Molecular regulation, breed differences and genes involved in stress control in farm animals. Domest Anim Endocrinol 2023; 82:106769. [PMID: 36244194 DOI: 10.1016/j.domaniend.2022.106769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 09/13/2022] [Accepted: 09/16/2022] [Indexed: 11/18/2022]
Abstract
Stress is a state of disturbed homeostasis evoking a multiplicity of somatic and mental adaptive reactions resulting from any of the 5 freedoms of animals being violated. Many environmental forces disrupt homeostasis in farm animals, such as extreme temperatures, poor nutrition, noise, hunger, and thirst. During stressful situations, neuronal circuits in the limbic system and prefrontal cortex are activated, which lead to the release of adrenalin and noradrenalin. The hormones released during stress are needed for adaptation to acute stress and are regulated by many genes. This review examined molecular regulation, breed differences, and genes involved in stress control in farm animals. Major molecular regulation of stress, such as oxidative, cytosolic heat shock, unfolded protein, and hypoxic responses, were discussed. The responses of various poultry, ruminant, and pig breeds to different stress types were also discussed. Gene expressions and polymorphisms in the neuroendocrine and neurotransmitter pathways were also elucidated. The information obtained from this review will help farmers mitigate stress in farm animals through appropriate breed and gene-assisted selection. Also, information obtained from this review will add to the field of stress genetics since stress is a serious welfare issue in farm animals.
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Affiliation(s)
- S O Durosaro
- Department of Animal Breeding and Genetics, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria; Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | - O S Iyasere
- Department of Animal Physiology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - B M Ilori
- Department of Animal Breeding and Genetics, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - V J Oyeniran
- Department of Animal Physiology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - M O Ozoje
- Department of Animal Breeding and Genetics, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
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Vakili R, Ebrahimnezhad Y. Impact of dietary supplementation of unsaturated and saturated fatty acids on bone strength, fatty acids profile of thigh muscle and immune responses in broiler chickens under heat stress. Vet Med Sci 2022; 9:252-262. [PMID: 36528892 PMCID: PMC9857130 DOI: 10.1002/vms3.1035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND There have been some reports that supplementation of fat could alleviate the negative effects of heat stress on performance in broilers. However, information regarding compensation for the adverse effects of heat stress with diets differing in fatty acids source on immune system, bone strength and carcass quality of heat-distressed broilers is limited. OBJECTIVES The objective of this study was to investigate the effects of diets differing in fat source on performance, immune system, bone strength, and carcass quality of heat-distressed broilers. METHODS In a completely randomized design with 4 × 2 factorial arrangement of the treatments, 320 24-day-old Ross 308 chickens, with average initial weight of 1220 ± 10 g were divided into eight treatments included sesame oil, tallow, sunflower oil and palm oil in either 22 or 32 degree of centigrade temperature. The broiler performance of each fat source-treated group was not different in this experiment and decreased significantly in heat stress condition. RESULTS Heat stress showed a significant increase on fat, energy and ash content of thigh muscle. Tibia absolute length, width, ash and bone breaking strength were affected by fat source and increased when sesame and sunflower oil were used. Data analysis revealed that hot temperature decreased tibia weight, length, width, ash and bone breaking strength. Heat stress led to decrease of immune system parameters. CONCLUSION Results suggest that there is no beneficial effect of broiler performance due to adding different sources of fat in broiler chicken diet under hot condition. Furthermore, the unsaturated fatty acids could improve the profile of fatty acids in thigh and enhance immune responses in broiler chickens.
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Affiliation(s)
- Reza Vakili
- Department of Animal ScienceKashmar Branch, Islamic Azad UniversityKashmarIran
| | - Yahya Ebrahimnezhad
- Department of Animal ScienceShabestar Branch, Islamic Azad UniversityShabestarIran
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Teyssier JR, Brugaletta G, Sirri F, Dridi S, Rochell SJ. A review of heat stress in chickens. Part II: Insights into protein and energy utilization and feeding. Front Physiol 2022; 13:943612. [PMID: 36003648 PMCID: PMC9393371 DOI: 10.3389/fphys.2022.943612] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/05/2022] [Indexed: 12/23/2022] Open
Abstract
With the growing global demand for animal protein and rising temperatures caused by climate change, heat stress (HS) is one of the main emerging environmental challenges for the poultry industry. Commercially-reared birds are particularly sensitive to hot temperatures, so adopting production systems that mitigate the adverse effects of HS on bird performance is essential and requires a holistic approach. Feeding and nutrition can play important roles in limiting the heat load on birds; therefore, this review aims to describe the effects of HS on feed intake (FI) and nutrient digestibility and to highlight feeding strategies and nutritional solutions to potentially mitigate some of the deleterious effects of HS on broiler chickens. The reduction of FI is one of the main behavioral changes induced by hot temperatures as birds attempt to limit heat production associated with the digestion, absorption, and metabolism of nutrients. Although the intensity and length of the heat period influences the type and magnitude of responses, reduced FI explains most of the performance degradation observed in HS broilers, while reduced nutrient digestibility appears to only explain a small proportion of impaired feed efficiency following HS. Targeted feeding strategies, including feed restriction and withdrawal, dual feeding, and wet feeding, have showed some promising results under hot temperatures, but these can be difficult to implement in intensive rearing systems. Concerning diet composition, feeding increased nutrient and energy diets can potentially compensate for decreased FI during HS. Indeed, high energy and high crude protein diets have both been shown to improve bird performance under HS conditions. Specifically, positive results may be obtained with increased added fat concentrations since lipids have a lower thermogenic effect compared to proteins and carbohydrates. Moreover, increased supplementation of some essential amino acids can help support increased amino acid requirements for maintenance functions caused by HS. Further research to better characterize and advance these nutritional strategies will help establish economically viable solutions to enhance productivity, health, welfare, and meat quality of broilers facing HS.
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Affiliation(s)
- Jean-Rémi Teyssier
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Jean-Rémi Teyssier, ; Samuel J. Rochell,
| | - Giorgio Brugaletta
- Department of Agricultural and Food Sciences, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Federico Sirri
- Department of Agricultural and Food Sciences, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Sami Dridi
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Samuel J. Rochell
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Jean-Rémi Teyssier, ; Samuel J. Rochell,
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Fathi MM, Galal A, Radwan LM, Abou-Emera OK, Al-Homidan IH. Using major genes to mitigate the deleterious effects of heat stress in poultry: an updated review. Poult Sci 2022; 101:102157. [PMID: 36167017 PMCID: PMC9513277 DOI: 10.1016/j.psj.2022.102157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 06/09/2022] [Accepted: 08/24/2022] [Indexed: 10/31/2022] Open
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Nawaz AH, Amoah K, Leng QY, Zheng JH, Zhang WL, Zhang L. Poultry Response to Heat Stress: Its Physiological, Metabolic, and Genetic Implications on Meat Production and Quality Including Strategies to Improve Broiler Production in a Warming World. Front Vet Sci 2021; 8:699081. [PMID: 34368284 PMCID: PMC8342923 DOI: 10.3389/fvets.2021.699081] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/24/2021] [Indexed: 12/21/2022] Open
Abstract
The continuous increase in poultry production over the last decades to meet the high growing demand and provide food security has attracted much concern due to the recent negative impacts of the most challenging environmental stressor, heat stress (HS), on birds. The poultry industry has responded by adopting different environmental strategies such as the use of environmentally controlled sheds and modern ventilation systems. However, such strategies are not long-term solutions and it cost so much for farmers to practice. The detrimental effects of HS include the reduction in growth, deterioration of meat quality as it reduces water-holding capacity, pH and increases drip loss in meat consequently changing the normal color, taste and texture of chicken meat. HS causes poor meat quality by impairing protein synthesis and augmenting undesirable fat in meat. Studies previously conducted show that HS negatively affects the skeletal muscle growth and development by changing its effects on myogenic regulatory factors, insulin growth factor-1, and heat-shock proteins. The focus of this article is in 3-fold: (1) to identify the mechanism of heat stress that causes meat production and quality loss in chicken; (2) to discuss the physiological, metabolic and genetic changes triggered by HS causing setback to the world poultry industry; (3) to identify the research gaps to be addressed in future studies.
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Affiliation(s)
- Ali H Nawaz
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China
| | - Kwaku Amoah
- Aquatic Animals Precision Nutrition and High-Efficiency Feed Engineering Research Center of Guangdong Province, Zhanjiang, China
| | - Qi Y Leng
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China
| | - Jia H Zheng
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China
| | - Wei L Zhang
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China
| | - Li Zhang
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China
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Attia YA, Al-Harthi MA, Hassan SS. Responses of broiler chicken to different oil levels within constant energy levels from 20 to 40 days of age under hot weather conditions. ITALIAN JOURNAL OF ANIMAL SCIENCE 2021. [DOI: 10.1080/1828051x.2021.1906169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Youssef A. Attia
- Agriculture Department, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammed A. Al-Harthi
- Agriculture Department, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Saber Sh. Hassan
- Animal and Poultry Production Department, Faculty of Agriculture, Damanhour University, Damanhour, Egypt
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Kumar M, Ratwan P, Dahiya SP, Nehra AK. Climate change and heat stress: Impact on production, reproduction and growth performance of poultry and its mitigation using genetic strategies. J Therm Biol 2021; 97:102867. [PMID: 33863431 DOI: 10.1016/j.jtherbio.2021.102867] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 01/15/2021] [Accepted: 01/24/2021] [Indexed: 10/22/2022]
Abstract
Heat stress is an important environmental determinant which adversely affects the performance of poultry worldwide. The present communication reviews the impact of heat stress on production, reproduction and growth performance of poultry, and its alleviation using genetic strategies. The adverse effects of high environmental temperature on poultry include decrease in growth rate, body weight, egg production, egg weight, egg quality, meat quality, semen quality, fertility and hatchability, which cause vast financial losses to the poultry industry. High ambient temperature has an antagonistic effect on performance traits of the poultry. Thus, selection of birds for high performance has increased their susceptibility to heat stress. Additionally, heat burden during transportation of birds from one place to another leads to reduced meat quality, increased mortality and welfare issues. Molecular markers are being explored nowadays to recognize the potential candidate genes related to production, reproduction and growth traits for selecting poultry birds to enhance thermo-tolerance and resistance against diseases. In conclusion, there is a critical need of formulating selection strategies based on genetic markers and exploring more genes in addition to HSP25, 70, 90, H1, RB1CC, BAG3, PDK, ID1, Na, F, dw and K responsible for thermoregulation, to improve the overall performance of poultry along with their ability to tolerate heat stress conditions.
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Affiliation(s)
- Manoj Kumar
- Department of Livestock Farm Complex, LUVAS, Hisar, 125004, Haryana, India.
| | - Poonam Ratwan
- Department of Animal Genetics and Breeding, LUVAS, Hisar, 125004, Haryana, India.
| | - S P Dahiya
- Department of Livestock Farm Complex, LUVAS, Hisar, 125004, Haryana, India.
| | - Anil Kumar Nehra
- Department of Veterinary Parasitology, LUVAS, Hisar, 125004, Haryana, India.
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9
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Naked neck and frizzle genes for improving chickens raised under high ambient temperature: I. Growth performance and egg production. WORLD POULTRY SCI J 2019. [DOI: 10.1017/s0043933913000834] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Characterisation of Saudi native chicken breeds: a case study of morphological and productive traits. WORLD POULTRY SCI J 2019. [DOI: 10.1017/s0043933917000563] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Lin H, Jiao H, Buyse J, Decuypere E. Strategies for preventing heat stress in poultry. WORLD POULTRY SCI J 2019. [DOI: 10.1079/wps200585] [Citation(s) in RCA: 237] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- H. Lin
- Department of Animal Science, Shandong Agricultural University, Taian, Shandong 271018, P.R. China
| | - H.C. Jiao
- Department of Animal Science, Shandong Agricultural University, Taian, Shandong 271018, P.R. China
| | - J. Buyse
- Lab of Animal Physiology and Immunology of Domestic Animal, Kasteelpark Arenberg 30, Katholic University Leuven, Belgium
| | - E. Decuypere
- Lab of Animal Physiology and Immunology of Domestic Animal, Kasteelpark Arenberg 30, Katholic University Leuven, Belgium
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12
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Cerrate S, Corzo A. Lysine and Energy Trends in Feeding Modern Commercial Broilers. ACTA ACUST UNITED AC 2018. [DOI: 10.3923/ijps.2019.28.38] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Heat stress in poultry production: Mitigation strategies to overcome the future challenges facing the global poultry industry. J Therm Biol 2018; 78:131-139. [DOI: 10.1016/j.jtherbio.2018.08.010] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/16/2018] [Accepted: 08/18/2018] [Indexed: 02/06/2023]
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14
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Mutibvu T, Chimonyo M, Halimani TE. Effects of strain and sex on the behaviour of free-range slow-growing chickens raised in a hot environment. JOURNAL OF APPLIED ANIMAL RESEARCH 2018. [DOI: 10.1080/09712119.2017.1287079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tonderai Mutibvu
- Animal and Poultry Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Michael Chimonyo
- Animal and Poultry Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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Gopinger E, Xavier EG, Lemes JS, Moraes PO, Elias MC, Roll VFB. Carcass yield and meat quality in broilers fed with canola meal. Br Poult Sci 2015; 55:817-23. [PMID: 25347330 DOI: 10.1080/00071668.2014.980394] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
1. This study evaluated the effects of canola meal in broiler diets on carcass yield, carcass composition, and instrumental and sensory analyses of meat. 2. A total of 320 one-day-old Cobb broilers were used in a 35-d experiment using a completely randomised design with 5 concentrations of canola meal (0, 10, 20, 30 and 40%) as a dietary substitute for soya bean meal. 3. Polynomial regression at 5% significance was used to evaluate the effects of canola meal content. The following variables were measured: carcass yield, chemical composition of meat, and instrumental and sensorial analyses. 4. The results showed that carcass yield exhibited a quadratic effect that was crescent to the level of 18% of canola meal based on the weight of the leg and a quadratic increase at concentrations up to 8.4% of canola meal based on the weight of the chest. The yield of the chest exhibited a linear behaviour. 5. The chemical composition of leg meat, instrumental analysis of breast meat and sensory characteristics of the breast meat was not significantly affected by the inclusion of canola meal. The chemical composition of the breast meat exhibited an increased linear effect in terms of dry matter and ether extract and a decreased linear behaviour in terms of the ash content. 6. In conclusion, soya bean meal can be substituted with canola meal at concentrations up to 20% of the total diet without affecting carcass yield, composition of meat or the instrumental or sensory characteristics of the meat of broilers.
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Affiliation(s)
- E Gopinger
- a Graduate Program in Animal Science , Federal University of Pelotas , 96010-900 Pelotas , Rio Grande do Sul , Brazil
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Gopi M, Purushothaman MR, Chandrasekaran D. Effect of dietary coenzyme Q10 supplementation on the growth rate, carcass characters and cost effectiveness of broiler fed with three energy levels. SPRINGERPLUS 2014; 3:518. [PMID: 25279310 PMCID: PMC4169782 DOI: 10.1186/2193-1801-3-518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/25/2014] [Indexed: 11/23/2022]
Abstract
The objective of this experiment was to study the effect of dietary supplementation of Coenzyme Q10 on broiler growth rate, carcass characteristics and cost of production. A biological trial was carried out with 270 broiler chicks fed with coenzyme Q10 at 0, 20 and 40 mg/kg of diet at each of the three energy levels. At the end of 42 days growth period the birds were sacrificed and the samples were analysed. Feed intake was comparable in all the energy and CoQ10 combinations, but higher body weight gain and better feed efficiency with less feed cost per kilogram weight gain was observed in high energy group supplemented with 20 mg of CoQ10/kg diet. The dressing percentages, weight of giblet, liver, spleen, abdominal fat, intestinal length were not significantly altered by CoQ10 supplementation. The heart weight, gizzard weight and ascites heart weight (AHI) were significantly decreased due to CoQ10 supplementation. Hence, birds fed with high energy diet supplemented with 20 mg CoQ10 per kg of diet had higher production performance.
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Affiliation(s)
- Marappan Gopi
- Department of Animal Nutrition, Veterinary College and Research Institute, Namakkal, India
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17
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Influence of major genes for crested-head, frizzle-feather and naked-neck on body weights and growth patterns of indigenous chickens reared intensively in Kenya. Trop Anim Health Prod 2009; 42:173-83. [PMID: 19579054 DOI: 10.1007/s11250-009-9403-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 06/17/2009] [Indexed: 10/20/2022]
Abstract
The influence of major genes for crested-head (Cr), frizzle-feather (Fr) and naked-neck (Na) on body weights and growth patterns of indigenous chickens reared intensively was investigated and compared with normal-feather (na) gene. Birds were individually weighed at hatch and every two weeks up to 30 weeks of age. Growth patterns were modelled using the Gompertz-Laird function. The genes influenced body weights and growth patterns at various ages. The Cr gene had significant (P < 0.05) negative effects on body weights (between 52.2 g and 112.3 g) from 18 weeks onwards and low absolute growth rate from 10 to 22 weeks than na, but higher initial specific growth and maturation rates than the Na gene. The Fr gene had significant negative effects on body weights (between 28.2 g and 75.1 g) from 8 to 16 weeks than na, but a higher relative growth rate than Cr from 12 to 16 weeks. The Na gene had significant negative effects on body weights (between 24.7 g and 134.6 g) from 8 weeks onwards than na. It was concluded that Frfr and Nana genotypes are not ideal for cool environments in Kenya and indigenous chicken genotypes have varied growth potentials and patterns that can be improved to increase production.
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de Almeida AM, Zuber U. The effect of the Naked Neck genotype (Nana), feeding and outdoor rearing on growth and carcass characteristics of free range broilers in a hot climate. Trop Anim Health Prod 2009; 42:99-107. [PMID: 19544084 DOI: 10.1007/s11250-009-9391-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 06/08/2009] [Indexed: 11/24/2022]
Abstract
Alternative poultry production with special reference to free range broilers has increased significantly since the nineties in many regions of the world. Numerous factors influence the productive performance of this type of broilers: genotype (namely the use of naked neck animals), feeding and access to an outdoor area. The aim of this paper is to study the influence of each of these factors on the productive performance of free range broilers under commercial rearing conditions. A total of 3200, day old chicks of both sexes from naked neck and normally feathered genotypes were used in this trial. After a joint initiation phase, animals were divided into four different treatments with the combination of two concentrates (high vs low energy content) and management (access to outside park or not). Experiment lasted a total of 12 weeks. Live weight date was recorded weekly and a samples of animals from the trial were sacrificed at the age of 8, 10 and 12 weeks, when carcass characteristics were determined. Besides sex, the only factor that seems to affect growth characteristics was genotype as naked neck animals had poorer growth rates than normally feathered. No effect was detected on carcass yields and percentages of carcass components for any of the variables. From the data presented in this trial the practises associated with free range production are of relative inconsequence to the technical animal production parameters and can only be justified by a pressing need to differentiate these products from standard poultry products in what concerns both welfare issues and meat characteristics. The results also indicate that genetic material from alternative poultry production in Europe can be a useful option in poultry production development projects in the tropics.
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Fathi M, El-Attar A, Ali U, Nazmi A. Effect of the naked neck gene on carcase composition and immunocompetence in chicken. Br Poult Sci 2008; 49:103-10. [DOI: 10.1080/00071660802005137] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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