Cleaner anaerobic fermentation and greenhouse gas reduction of crop straw.

Rice anaerobic fermentation is a significant source of greenhouse gas (GHG) emissions, and in order to efficiently utilize crop residue resources to reduce GHG emissions, rice straw anaerobic fermentation was regulated using lactic acid bacteria (LAB) inoculants (FG1 and TH14), grass medium (GM) to culture LAB, and Acremonim cellulolyticus (AC). Microbial community, GHG emission, dry matter (DM) loss, and anaerobic fermentation were analyzed using PacBio single-molecule real-time and anaerobic fermentation system. The epiphytic microbial diversity of fresh rice straw was extremely rich and contained certain nutrients and minerals. During ensiling, large amounts of GHG such as carbon dioxide are produced due to plant respiration, enzymatic hydrolysis reactions, and proliferation of aerobic bacteria, resulting in energy and DM loss. Addition of FG1, TH14, and AC alone improved anaerobic fermentation by decreasing pH and ammonia nitrogen content (P < 0.05) and increased lactic acid content (P < 0.05) when compared to the control, and GM showed the same additive effect as LAB inoculants. Microbial additives formed a co-occurrence microbial network system dominated by LAB, enhanced the biosynthesis of secondary metabolites, diversified the microbial metabolic environment and carbohydrate metabolic pathways, weakened the amino acid metabolic pathways, and made the anaerobic fermentation cleaner. This study is of great significance for the effective utilization of crop straw resources, the promotion of sustainable livestock production, and the reduction of GHG emissions.IMPORTANCETo effectively utilize crop by-product resources, we applied microbial additives to silage fermentation of fresh rice straw. Fresh rice straw is extremely rich in microbial diversity, which was significantly reduced after silage fermentation, and its nutrients were well preserved. Silage fermentation was improved by microbial additives, where the combination of cellulase and lactic acid bacteria acted as enzyme-bacteria synergists to promote lactic acid fermentation and inhibit the proliferation of harmful bacteria, such as protein degradation and gas production, thereby reducing GHG emissions and DM losses. The microbial additives accelerated the formation of a symbiotic microbial network system dominated by lactic acid bacteria, which regulated silage fermentation and improved microbial metabolic pathways for carbohydrates and amino acids, as well as biosynthesis of secondary metabolites.

Silage preparation and sustainable livestock production of natural woody plant.

As the global population increases and the economy grows rapidly, the demand for livestock products such as meat, egg and milk continue to increase. The shortage of feed in livestock production is a worldwide problem restricting the development of the animal industry. Natural woody plants are widely distributed and have a huge biomass yield. The fresh leaves and branches of some woody plants are rich in nutrients such as proteins, amino acids, vitamins and minerals and can be used to produce storage feed such as silage for livestock. Therefore, the development and utilization of natural woody plants for clean fermented feed is important for the sustainable production of livestock product. This paper presents a comprehensive review of the research progress, current status and development prospects of forageable natural woody plant feed resources. The nutritional composition and uses of natural woody plants, the main factors affecting the fermentation of woody plant silage and the interaction mechanism between microbial co-occurrence network and secondary metabolite are reviewed. Various preparation technologies for clean fermentation of woody plant silage were summarized comprehensively, which provided a sustainable production mode for improving the production efficiency of livestock and producing high-quality livestock product. Therefore, woody plants play an increasingly important role as a potential natural feed resource in alleviating feed shortage and promoting sustainable development of livestock product.

miR-15a regulates the preadipocyte differentiation by targeting ABAT gene in Yanbian yellow cattle.

MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs of approximately 21 to 23 nucleotides in length. Owing to their regulation of gene expression and many physiological processes including fat metabolism, they have become a popular research topic in recent years; however, the exact functional mechanisms by which they regulate fat metabolism have not been fully elucidated. Here, we identified miR-15a, which specifically acquired the 3' untranslated region (UTR) containing 4-aminobutyrate aminotransferase (ABAT), and validated the regulation of its expression and involvement in adipogenesis mechanisms. We used a dual-luciferase reporter assay and transfection-mediated miR-15a overexpression and inhibition in Yanbian yellow cattle preadipocytes to investigate the role of miR-15a in adipogenesis. The results showed that miR-15a directly targets the 3'UTR of ABAT and downregulates its expression. Additionally, at the protein and mRNA levels, miR-15a overexpression using a miRNA mimic inhibited triglyceride accumulation and downregulated lipogenic peroxisome proliferator-activated receptor γ and CCAAT enhancer-binding protein α, whereas miR-15a inhibition had the opposite effect. The above results indicated that miR-15a regulated the differentiation of Yanbian yellow cattle preadipocytes by inhibiting the expression of ABAT. Furthermore, our findings suggested that miR-15a and its target gene(s) might represent new targets for investigating intramuscular fat deposits in cattle and treating human obesity.

miR-381 Targets KCTD15 to Regulate Bovine Preadipocyte Differentiation In Vitro.

MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs ~21 to ~23 nucleotides in length and have become a popular research topic in recent years due to their regulation of gene expression and many physiological processes, including fat metabolism; however, the precise functional mechanisms underlying their regulation of fat metabolism are not fully understood. Here, we identified miR-381, which specifically targets the 3' untranslated region (3' UTR) of potassium channel tetramerization-domain-containing 15 (KCTD15) , and verified the mechanism regulating its expression and participation in adipogenesis. We used a dual luciferase-reporter assay and transfection-mediated miR-381 overexpression and inhibition in Yanbian yellow cattle preadipocytes to investigate the role of miR-381 in adipogenesis. The results showed that miR-381 directly targets the 3' UTR of KCTD15 and downregulates its expression. Additionally, miR-381 overexpression using an miRNA mimic promoted triglyceride accumulation and upregulated adipogenic peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT enhancer-binding protein α (C/EBPα) at both the protein and mRNA levels, whereas miR-381 inhibition produced the opposite effect. These results indicated that miR-381 regulates the differentiation of Yanbian yellow cattle preadipocytes by inhibiting KCTD15 expression, thereby highlighting the importance of miRNA-mediated regulation of adipogenesis. Furthermore, our findings suggested that miR-381 and its target gene(s) might represent new targets for investigating intramuscular fat deposits in cattle and treating human obesity.

Correlations between single nucleotide polymorphisms in FABP4 and meat quality and lipid metabolism gene expression in Yanbian yellow cattle.

FABP4 is a candidate gene for carcass and meat quality traits in livestock and poultry. However, the effects of FABP4 have not been examined in the Yanbian yellow cattle, an economically important local cattle breed in China. In this study, we characterized single nucleotide polymorphisms (SNPs) in FABP4 in this cattle breed and their associations with meat quality traits. Six SNPs (referred to as SNP1-6) were identified in FABP4 by direct sequencing and polymerase chain reaction-restriction fragment length polymorphism. The six SNPs were significantly correlated with meat quality traits. In particular, the GG and GA genotypes of SNP1 were significantly associated with water and fat contents and GG and AA genotypes of SNP1 were significantly associated with protein contents (P < 0.05). The fat content and marbling in heterozygous individuals at SNP2-6 were significantly higher than those in wild-type or mutant individuals (P < 0.05), while protein content was significantly higher in wild-type and mutant individuals than in heterozygous individuals (P < 0.05). A gene expression analysis indicated that the lipid metabolism-related genes FABP4, PPARγ, ANGPTL4, and LPL show similar expression patterns with respect to FABP4 genotypes, with the highest levels in wild-type individuals and the lowest levels in mutants. In conclusion, FABP4 SNPs can be used for marker-assisted selection in Yanbian yellow cattle breeding.

Effects of apple pomace-mixed silage on growth performance and meat quality in finishing pigs.

We measured the growth performance and meat quality of 10 crossbred (Yorkshire × Duroc × Landrace) neutered male pigs to evaluate the effects of apple pomace-mixed silage (APMS). The pigs were divided into two groups and were respectively fed the control feed and the AMPS ad libitum during the experiment. No difference was found in the finished body weight, average daily gain, carcass weight, back fat thickness or dressing ratio between the control and the AMPS treatments, but average dairy feed intake (dry matter) was significantly lower and feed efficiency was significantly higher using the APMS treatment (P < 0.05). With regard to meat quality, the APMS increased the moisture content but decreased the water holding capacity (P < 0.05) compared with the control treatment. Furthermore, the APMS affected the fatty acid composition of the back fat by increasing linoleic acid (C18:2n6), linolenic acid (C18:3) and arachidic acid (C20:0) levels, while decreasing palmitic acid (C16:0), palmitoleic acid (C16:1) and heptadecenoic acid (C17:1) levels, compared with the control treatment. These results indicate that feeding fermented apple pomace to finishing pigs increases the feed efficiency and affects the meat quality and fatty acid composition of back fat.

Effects of apple pomace proportion levels on the fermentation quality of total mixed ration silage and its digestibility, preference and ruminal fermentation in beef cows.

Four Japanese black beef cows were used in a 4 × 4 Latin square to evaluate the fermentation quality, digestibility, ruminal fermentation and preference of total mixed ration (TMR) silages prepared with differing proportions of apple pomace (AP). Experimental treatments were the control (no AP added, CAP), 5% (low, LAP), 10% (medium, MAP) and 20% (high, HAP) of TMR dry matter (DM) as AP. All TMR silages were well preserved. Ethanol was produced in silages containing AP and the amount increased with the proportion of AP (P < 0.05). Nutrient digestibility with LAP, MAP and HAP treatment was lower than that with CAP treatment (P < 0.05). The ruminal molar proportion of acetic acid increased (P < 0.05), but the ruminal ammonia-N concentration decreased (P < 0.05) as the proportion of AP increased. The preference of the animals was highest for HAP, followed by MAP, CAP and LAP. This study demonstrates that decrease in nutrient digestibility might be related to the ethanol produced naturally from AP. Therefore, the proportion of AP in TMR silages should be less than 5% of dietary DM.