Effects of genetic group × ambient temperature interactions on performance and physiological responses of Naked-neck chickens and their F₁ crosses with Lohmann White and New Hampshire laying hens

Abstract

The objective of this study was to evaluate the effects of genotype x temperature interactions on hormonal heat stress indicators and performance traits. Two-hundred forty female oneday-old chicks were randomly assigned to a completely randomized design in a 5×2 factorial arrangement with 5 genotypes (Naked-neck, Na, from Ethiopia; New Hampshire, NH; Lohmann White, LW and F 1 crosses of Na with NH and LW) and 2 ambient temperatures (thermo-neutral, 18-20 o C; heat stress, 30-32 o C). Blood samples were taken from 12 randomly selected birds per genotype and ambient temperature at 22, 38, 51 and 65 weeks of age. Levels of corticosterone (CS) and 3,5,3′-triiodothyronine (T 3 ) were determined in blood plasma. Heat stress effects on egg production traits were most severe in LW and NH, least severe in Na and Na × LW, intermediate in Na × NH. Plasma T 3 level was significantly reduced by 27.9% in heat stressed genotypes. Plasma CS increased by 12.6% in heat exposed genotypes. However, inconsistent responses of CS and T 3 levels were observed at different ages. The Na and their F 1 crosses demonstrated relatively better thermotolerance than LW and NH hens. Levels of plasma T 3 hormone might be considered as indicator of long-term heat stress in hens. HEAT STRESS -LAYING PERFORMANCE

Impact of Heat Stress on Poultry Health and Performances, and Potential Mitigation Strategies

“…Dwarf gene (dw) is found to inhibit the conversion of T4 to T3 in peripheral tissue, resulting in a lower T3 level in dwarfs [ 31 ]. Melesse et al [ 32 ] also reported a lower level of T3 in Naked neck laying hens as compared to Lohman white and New Hampshire laying hens. Besides this, the secretion of the gonadotrophin-releasing hormone is also found to be impaired in heat-stressed birds [ 33 ].…”

Significance of scavenging chicken production in the rural community of Africa for enhanced food security

“…Considerable work has been done on the crossbreeding of local breeds with exotics in some African countries such as Ethiopia (Melesse et al, 2005;2011b;2011c). On the other hand, crossbreeding offers a chance to exploit heterosis and the development of synthetic lines.…”

Genetic improvement approaches of indigenous cattle breeds for adaptation, conservation and sustainable utilization to changing climate in Ethiopia

“…This is especially important as the climate becomes warmer, conditions for diseases occurrences turn out to be more favorable and feed resources become scarce leading to cost rises (Hoffmann, 2010;Kantanen et al, 2015). Adaptive characteristics to climate change encompass a wide range of physiological, behavioral, and morphological features (Melesse et al, 2011a;Melesse et al, 2011b;Melesse, 2016;Bayssa et al, 2020). Climate change adaptation strategies address not only livestock tolerance to heat, but also disease resistance, water scarcity tolerance, and the ability to cope with poor quality feed.…”

“…Such measures may include conducting characterization studies to identify the local animal genetic resources that have the potential to be adapted to local climate conditions and feed sources (Melesse et al, 2022). Moreover, improving the genetic potentials of the local breeds through cross-breeding with heat and disease-tolerant breeds might be another option to explore (Melesse et al, 2011a;Melesse et al, 2011b). According to Aby and Meuwissen (2014), an efficient approach is the introgression of locally adaptive genes into commercial breeds through efficient breeding strategies that may be needed to bring better adapted to rapidly changing environmental conditions.…”