Search

Previous studies reported that the Myoz1 gene plays a crucial role in signal transduction and muscle fibre type differentiation. This finding suggests that the Myoz1 gene is a potential candidate for affecting carcase and meat quality traits in animals. Therefore, this study aimed to detect genetic variations in Avian and Yellow Bantam chickens and to evaluate the effects of these variations on economically important carcase and meat-quality traits. Expression analysis using quantitative real-time PCR indicated that Myoz1 was broadly expressed in all four studied tissues (liver, heart, breast muscle and leg muscle). Expression of Myoz1 was significantly higher in both leg muscle and breast muscle compared to the liver and heart. Then, using direct sequencing, a total of five single nucleotide polymorphisms (SNPs) were identified within the Myoz1 gene in two breeds of chickens. These breeds included three non-synonymous SNPs (SNP1: g. 16022512 G > T, SNP3: g. 16022560 C > T and SNP5: g.16023903 A > G) corresponding to A103S, H119Y and S189G, respectively. Statistical analyses indicated that SNP2 (g. 16022529 T > C), SNP3, SNP4 (g.16023878 A > C) and SNP5 significantly influenced some carcase and meat quality traits. Meanwhile, we did not find any association between the constructed haplotype and carcase traits in the Avian nor Yellow Bantam chickens. In conclusion, SNPs in the Myoz1 gene could be used for marker-assisted selection in chicken breeding. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of housing system (cage versus pen), sex and line cross (EMY1 and EMY2) on meat quality in meat-type chickens. Chickens (n=640) from each line cross (males: females=1:1) were housed in batteries from d 1 to 28. Then, half of them were transferred to indoor floor pens, and the others were raised in single cages. Meat quality traits of breast fillets were measured at 91 d of age. Percent lipid and histidine were higher, whereas % total protein and myofibre density (MDS) were lower in caged than penned chickens. Cross EMY1 had higher MDS, but lower lipid % and myofibre diameters (MDM) than EMY2 (p<.05). Males had redder and brighter muscles and higher MDM and contents of glycine and proline than the females (p<.05). Penned females had smaller MDM and higher MDS than their caged counterparts (p<.05). Generally, housing systems alone, or interacting with sex and genetic line, affected yellowness, myofibre characteristics, % protein, % lipid, myofibre density, and % His of breast muscle. [ABSTRACT FROM AUTHOR]

Tibetan chicken (TC) is a unique chicken breed that has inhabited the Tibetan Plateau for thousands of years and has adapted to the harsh environment of an altitude of over greater than 4000 m. The changes in blood characteristics that occur in high-altitude rearing of TCs are unknown. To obtain a deeper insight into the blood characteristics of chickens in low and high altitudes, we focussed on four chicken populations to compare the variations among them. In the present study, we found significant differences in white blood cell (WBC) count, red blood cell (RBC) count and haematocrit (HCT) values between TCs and other chicken populations. When TCs were reared at low altitude, there was a significant (p < .05) decrease in the WBC, RBC and HCT values compared with the TCs reared at high altitude; however, whether the mean corpuscular volume (MCV) value is related to oxygen transport and hypoxia adaptation requires further study. It is likely that haemoglobin (HGB), mean corpuscular haemoglobin (MCH) and MCH concentration (MCHC) values are decrease at high-altitude hypoxic environments. Therefore, the increase in WBC, RBC and HCT values may be the common haematological mechanism for TCs to adapt to high-altitude hypoxia. These research results provide the scientific basis and theory to explain how TCs are able to adapt to high-altitude hypoxia. [ABSTRACT FROM PUBLISHER]