Since the first report of chicken infectious anemia virus (CIAV) in Vietnam in 2013, there have not been many studies focused on the detection of CIAV or the molecular characteristics of the virus. This study attempted to investigate the presence of CIAV in northern Vietnam by molecular-based methods. Regarding the spatial distribution of CIAV, the PCR-based results showed that CIAV was detected in 47 out of 64 farms (73.4%) and in all 10 investigated provinces. Of the 119 samples assayed by PCR, 74 (62.2%) tested positive for CIAV DNA. By arranging the samples into different categories, it was found that CIAV was detected at high rates (above 50%) based on all 4 evaluated criteria as follows: production type of chicken, housing system, flock size and age group. Different housing systems were significantly associated with the detection rates of CIAV (p = 0.003). By genetic analyses, all of the Vietnamese CIAVs were found to (i) lack substitutions related to attenuation substitutions, (ii) group separately from vaccine-like CIAVs and (iii) belong to genogroups G2 and G3 of CIAV. Because of the wide distribution of CIAV and because the virus was confirmed not to be vaccine-like viruses, it is suggested that further studies be conducted on the clinical form of chicken infectious anemia, as well as the immunosuppressive effect of CIAV on chickens in Vietnam.

The objective of this work was the evaluation of the meat production and laying performances, and the meat and egg quality of two breeds of Vietnamese broiler chickens, Ho and Dong Tao, fed on a commercial diet. In a survey, we continuously recorded for 28 weeks, the data on the production performance and meat quality of 250 chicks from each breed. We investigated egg laying and egg quality using 36 Ho and 32 Dong Tao hens during 52 weeks of laying. The growth patterns were similar for the two breeds. Feed conversion ratios were also similar, and demonstrated the low efficiency of these two breeds when compared to commercial broilers. Slaughter age proved to affect several carcass yield characteristics, showing that slaughtering between 16 and 20 weeks might be better than at the usual age of 28 weeks. Yield, carcass composition and meat quality differed between the two studied breeds. The eggs production and number of embryonated eggs were low for the two breeds when compared to other breeds, with a lower hatching performance in Ho than in Dong Tao. In summary, the production performances of Ho and Dong Tao chickens were low, even when birds were fed a commercial diet. The study demonstrates the need to find ways to improve the production and reproduction performances of these animals, in order to contribute to the program of conservation and exploitation of these two breeds.

As the prices of corn, wheat, and soybean meal have risen with fluctuations [1,2], alternative sources have gained increasing attention as a practical solution to reduce feed costs and reliance on traditional feed ingredients [1]. Because nutrient concentrations, including protein and fiber, vary among the alternative feed ingredients, an accurate evaluation of digestibility of nutrients in alternatives is necessary to replace the conventional sources in swine diets [3].

The alpha (1) fucosyltransferase gene (FUT1) is a candidate gene for controlling the adhesion of Escherichia coli F18 receptor. Indeed, a single-nucleotide polymorphism, c.307G>A, located in the gene is such that pigs with AA genotype are resistant to entero-toxigenic E. coli F18, whereas those with AG and GG genotypes are sensitive. An experiment was carried out in northern Vietnam from March 2016 to May 2017 to determine FUT1 genotype frequencies and the effect of these genotypes on production performance of Yorkshire pigs. A total of 613 animals were genotyped using polymerase chain reaction – restriction fragment length polymorphism method. The body weights at birth, weaning, initial fattening period, and final fattening period were collected from 611, 516, 479, and 418 animals, respectively, whereas backfat thickness, depth of longissimus dorsi, and lean meat percentage were recorded from 328 animals. The frequencies of FUT1 genotypes were found to be in Hardy–Weinberg equilibrium (P = 0.51). Effect of FUT1 genotype was not observed for all production traits (P > 0.05), whereas final body weight and depth of longissimus dorsi were significantly different between females and males (P < 0.05). These results suggest that selection of Yorkshire pigs resistant to entero-toxigenic E. coli F18 could be effective without adversely affecting average daily gain and lean meat.

| Prolactin receptor (PRLR) and vertnin (VRTN) gene is considered as genetic marker for teat, vertebrae and ribs number in pigs. In this study, the polymorphisms of these genes was investigated in Landrace, Yorkshire and Meishan purebred pigs. A total of 102 animals including 37 Landrace, 35 Yorkshire and 30 Meishan were collected from Thuy Phuong Pig Research and Development Center, Vietnam National Institute of Animal Science, Vietnam. Pig individuals were genotyped with PCR and PCR-RFLP methods. Allelic and genotypic frequencies were calculated. Hardy-Weinberg equilibrium (HWE) was performed using χ 2-test. For PRLR, 3 genotypes (AA, AB and BB) were detected and the most abundant genotype was the heterozygous one. The frequencies of expected genotype AA were 0.35, 0.40, and 0.17 for Landrace, Yorkshire, and Meishan, respectively. Frequencies of allele A were 0.61 (Landrace), 0.69 (Yorkshire), and 0.59 (Meishan). The loci were in HWE for all group of pigs except Meishan. For VRTN, those values for QQ genotype were 0.30 (Landrace), 0.37 (Yorkshire), and 0.10 (Meishan), while Q allele frequencies were 0.43 (Landrace), 0.57 (Yorkshire), and 0.22 (Meishan). HWE was detected for Meishan Pig.