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Background and Aim: A Luoi Yellow cattle is an indigenous cattle breed that is raised in the A Luoi District, Vietnam, characterized by its small body size, high adaptability, and meat quality favored by domestic consumers. Marker-assisted selection is an effective approach for improving breeding genetics and sustainably developing livestock production. Therefore, this study aimed to investigate the genetic diversity and polymorphism of genes associated with meat quality and productivity in the A Luoi Yellow cattle population with the goal of future breeding selection and sustainable development of the A Luoi Yellow beef brand. Materials and Methods: In this study, we genotyped six functional genes, including Leptin (LEP), Calpastatin (CAST), Calpain 1, pleomorphic adenoma gene 1, Sirtuin 1, and Sirtuin 2 (SIRT2), involved in meat quality and growth traits using polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphis. We also investigated mitochondrial DNA (mtDNA) and the Y chromosome-specific gene on the Y chromosome to elucidate the genetic diversity and paternal and maternal origin of the A Luoi Yellow cattle using Sanger sequencing. Results: The results showed that A Luoi yellow cattle have Bos indicus origin from both paternal and maternal lineages. By mtDNA analysis, we identified two new haplotypes of the I1 haplogroup that were not previously detected. The genotyping of the six functional genes indicated that A Luoi Yellow cattle carry favorable alleles that increase meat tenderness and body size, with frequencies of 0.02–0.40. In particular, the presence of desirable homozygous genotypes of the CAST, LEP, and SIRT2 genes will be important for the future selection of animals based on their potential performance in meat quality and productivity. Conclusion: The findings of this study is useful for the future breeding and sustainable development of A Luoi Yellow cattle.

Objective Research was conducted to test the effect of including fiber-rich feedstuffs in practical pig diets on nutrient digestibility, nitrogen balance and ammonia emissions from slurry. Methods Three Vietnamese fiber sources were screened, namely cassava leaf meal (CL), cassava root residue (CR), and tofu by-product (TF). Accordingly, a control diet (Con) with 10% of dietary non-starch polysaccharides (NSP) and three test diets including one of the three fiber-rich feedstuffs to reach 15% of NSP were formulated. All formulated diets had the same level of crude protein (CP), in vitro ileal protein digestible and metabolisable energy, whereas the in vitro hindgut volatile fatty acid (VFA) production of the test diets was 12% to 20% higher than the control diet. Forty growing barrows with initial body weight at 28.6±1.93 kg (mean±standard deviation) were allocated to the four treatments. When pigs reached about 50 kg of body weight, four pigs from each treatment were used for a nitrogen balance trial and ammonia emission assessment, the remaining six pigs continued the second period of the feeding trial. Results The TF treatment increased fecal VFA by 33% as compared with the control treatment (p = 0.07), suggesting stimulation of the hindgut fermentation. However, urinary N was not significantly reduced or shifted to fecal N, nor was slurry pH decreased. Accordingly, ammonia emissions were not mitigated. CR and CL treatments failed to enhance in vivo hindgut fermentation, as assessed by fecal VFA and purine bases. On the contrary, the reduction of CP digestibility in the CL treatment enhanced ammonia emissions from slurry. Conclusion Dietary inclusion of cassava and tofu byproducts through an increase of dietary NSP from 10% to 15% might stimulate fecal VFA excretion but this does not guarantee a reduction in ammonia emissions from slurry, while its interaction with protein digestibility even might enhance enhanced ammonia emission.