It is well known, that the ω6:ω3 PUFA (polyunsaturated fatty acids) ratio of the egg yolk can be changed by modifying the hen's diet. Information on genetic effects on PUFA in egg yolks is limited. Therefore four generations of divergent selection of high and low ω6:ω3 PUFA ratio were performed with quails as model animals to estimate genetic effects on the fatty acid profile of eggs. Heritability and correlated response to selection were analysed. Generation 4 consisted of 125 hens in the HIGH and 114 hens in the LOW line and 40 sires per line. Fatty acid profiles of the eggs were measured on pools of 3 yolks per hen, two times per hen. After four generations of selection ω6:ω3 PUFA ratio was significantly different in the LOW (12.4) and HIGH line (14.9), i.e. a difference of 1.6 phenotypic standard units. Heritability for ω6:ω3 PUFA ratio was estimated at 0.45 (SE 0.05). Selection tended to be asymmetric in the way that response to selection in the LOW line was higher. Fertility and hatchability of fertile, age at first egg, laying intensity, egg weight and fat percentage were not significantly different between selected lines, but yolk weight, yolk proportion and fat content were significantly higher in the Low line. Moderate heritability of ω6:ω3 PUFA ratio in egg yolks and lack of correlated responses to selection in major production and reproduction traits indicate that breeding for a lower ω6:ω3 PUFA ratio in eggs is promising.

This study focused on the association of polymorphisms of the FADS2 gene with fatty acid profiles in egg yolk of eight Japanese quail lines selected for high and low omega-6:omega-3 PUFA ratio (h2 = 0.36-0.38). For the identification of polymorphisms within the FADS2 gene 1350 bp of cDNA sequence were obtained encoding 404 amino acids. Five synonymous SNPs were found by comparative sequencing of animals of the high and low lines. These SNPs were genotyped by single base extension on 160 Japanese quail. The association analysis, comprising analysis of variance and family based association test (FBAT), revealed significant effects of SNP3 and SNP4 genotypes on the egg yolk fatty acid profiles, especially the omega-6 and omega-3 PUFAs (P < 0.05). No effects of the other SNPs were found - indicating that these are not in linkage disequilibrium with the causal polymorphism. The results of this study promote FADS2 as a functional candidate gene for traits related to omega-6 and omega-3 PUFA concentration in the egg yolk.

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This study was carried out to evaluate the effect of vitE (Vitamin E) supplementation in combination with vitC (Vitamin C) on reproductive performance and hatching rate of Japanese quail at the age of 59-114 days. A total of 132 laying quails were arranged in a completely randomized design with 3 treatments and 4 replicates, each replicate being 9 female quails and 2 male quails at 59 days of age. The experimental treatments were as follows: control fed the basal diet (KPCS), E125C75 including KPCS supplemented with 125 mg vitE/kg feed combined with 75 mg vitC/kg feed and E125C125 including KPCS supplemented 125 mg vitE/kg feed combined with 125 mg vitC/kg feed. Research results showed that the highest WG (Weight Gain) was in E125C125 (30.32 g) and lowest in E125C75 (17.37 g). There were no statistically significant differences between treatments in terms of laying rate, feed conversion ratio, egg mass and egg weight. However, hatching rate and bodyweight of quails at 1 day of age were significantly different between treatments, the highest was E125C125 (74.37% and 7.43 g), followed by E125C75 (70.02% and 7.03 g) and the lowest was control (65.89% and 6.82 g). It can be concluded that E125C125 not only improved laying rate but also increased hatching rate and bodyweight of quail chick.

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Calpastain (CAST) activity plays a major role in muscle growth and proteolytic changes post-mortem and the CAST gene has been considered as a candidate gene for carcass and pork quality characteristics. The aim of this study was to analyze the association of two polymorphisms namely CAST_HinfI (allele A and B) and CAST_MspI (allele C and D) with carcass and meat quality traits in Mongcai, a Vietnamese indigenous pig breed. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to genotype the animals at these loci. Results indicate that the CAST_HinfI single nucleotide polymorphism (SNP) had a low frequency of allele A as compared to allele B, while the C and D allele distribution was almost the same for the CAST_MspI SNP. In the association analysis, significant effects on dressing percentage of carcass were detected. The CAST_HinfI locus was associated with the pH 24 , while the CAST_MspI position was in association with pH 45 min , drip loss 48 and redness color. Additional analysis showed a variation in muscle fiber type composition with higher proportion of IIx fiber in pigs with AB genotype (P < 0.05). Three constructed haplotypes namely AB/CD, AB/DD and BB/CC also had significant effects on carcass, type IIa and IIb fiber percentages.

Noi chicken, a local breed of chicken in Vietnam, is popularly raised in the Mekong Delta. The advantages of the local chicken breeds are that they are well adapted to the local environmental conditions, find their own feed well, and have delicious meat quality but very low growth and reproductive performance (Quyen and Son 2008; Padhi 2016). Beside, the major problem is the low fertility rate due to the cock to female ratio (1:5-8), which results from natural mating and, of course, leads to poor breeding performance.Currently, artificial insemination (AI) is one of the most optimal methods of the conservation of genetic resources of local livestock breeds because of its low cost and high profit, as semen from a single breeder cock can be used for multiple hens. However, the key to success in using AI is the quality of sperm (Mohann et al 2018). There are many factors that affect sperm quality, such as the breed and strains of chickens (