Assessing the thermo-tolerance potentials of five commercial layer chicken genotypes under long-term heat stress environment as measured by their performance traits This study was conducted to test ...the thermo-tolerance ability of five commercial chicken genotypes (Lohmann Brown, LB; Lohmann White, LW; New Hampshire, NH ; White Leghorn selected for low feed expenditure, WL-FE and White Leghorn with sex-linked dwarf gene, WL-dw) under long-term heat exposure. Two-hundred forty female chickens were assigned to a completely randomized design in a 5 × 2 factorial arrangements (five genetic groups and two ambient temperatures thermo-neutral, 18-20 °C; heat stress, 30-32 °C). Individual eggs were collected on daily basis while egg weight and feed intake were determined on individual and group basis at 28-days intervals, respectively. Shell quality traits were determined at 25, 40 and 56 weeks age. No Genotype × ambient temperature interactions were found except for body weight and egg deformation. Chickens at thermo-neutral temperature produced significantly heavier eggs than those of heat-exposed (60 g vs. 54 g). Hen-housed egg production of chickens in thermo-neutral temperature was significantly higher than those of heat-stressed (76.8 % vs. 66.2 %). Daily egg mass production at thermo-neutral and heat stressed chickens was 46 g and 35.8 g, respectively. Feed consumption in heat-stressed and thermo-neutral chickens was 109 and 80.8 g, respectively. Shell thickness, breaking strength and Haugh unit values were significantly reduced in heat-stressed chickens. Among heat-exposed chickens, the NH had the highest body weight while the LW produced 10 % more eggs than the group average. The heat-induced effect on shell quality traits was lowest in LW chickens. The results indicated that the magnitude of heat stress was breed dependent in which the LB showed poor adaptability to heat stress while both NH and LW genotypes demonstrated better thermo-tolerance ability.
Congenital splay leg is a hereditary disease observed in newborn piglets. The etiology and pathogenetic mechanism of the disorder are still unknown. The gene for cyclin-dependent protein kinase ...inhibitor 3 (CDKN3) was identified as a potential candidate gene in a differential display experiment. We analyzed the gene on sequence variations and compared its expression in M. biceps femoris between healthy and affected piglets. Comparative sequencing of the coding region of three healthy and four splay leg piglets revealed twelve single nucleotide polymorphisms (SNP) resulting in six amino acid exchanges in the deduced sequences. However, all polymorphisms were observed in healthy as well as in splay leg piglets thus excluding structural differences of the gene as a cause of the disease. Besides full length transcripts, we found a variety of aberrantly transcribed cDNA in clones derived from M. biceps femoris of healthy as well as of splay leg piglets. All alternative transcripts coexist with normal cDNA. Expression analysis revealed a trend towards higher values in M. biceps femoris of splay leg piglets supporting the results obtained from a differential display.
Congenital splay leg is a hereditary disease observed in newborn piglets. The etiology and pathogenetic mechanism of the disorder are still unknown. The gene for cyclin-dependent protein kinase ...inhibitor 3 (CDKN3) was identified as a potential candidate gene in a differential display experiment. We analyzed the gene on sequence variations and compared its expression in M. biceps femoris between healthy and affected piglets. Comparative sequencing of the coding region of three healthy and four splay leg piglets revealed twelve single nucleotide polymorphisms (SNP) resulting in six amino acid exchanges in the deduced sequences. However, all polymorphisms were observed in healthy as well as in splay leg piglets thus excluding structural differences of the gene as a cause of the disease. Besides full length transcripts, we found a variety of aberrantly transcribed cDNA in clones derived from M. biceps femoris of healthy as well as of splay leg piglets. All alternative transcripts coexist with normal cDNA. Expression analysis revealed a trend towards higher values in M. biceps femoris of splay leg piglets supporting the results obtained from a differential display.
Large individual differences were observed in the abundance of transcripts from the
hsp70.2 gene in primary fibroblast cultures sampled from 15 different pigs. While previously described functional ...promoter variants of this gene can partly account for the high variability of heat-induced increased abundance of transcripts, they are unrelated to the observed highly variable absolute amounts of
hsp70.2 transcripts. Comparative sequence analysis revealed an alteration of the 3′-untranslated region (3′-UTR) sequences in these samples. The variant 3′-UTR allele proved to increase the half life of the
hsp70.2 mRNA in reporter gene assays. It is suggested that the cellular stress response is significantly affected by the action and interaction of both promoter and 3′-UTR variants of the
hsp70.2 gene.
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