Dynamics associated with fermentation and aerobic deterioration of high-moisture Italian ryegrass silage made using Lactobacillus plantarum and caproic acid.

AIMS: To determine the fermentation quality, aerobic stability, and chemical composition of Italian ryegrass silage prepared with Lactobacillus plantarum (LP), caproic acid (CA), and their combination during ensiling and feed-out phase. METHODS AND RESULTS: Six treatments: control (CON), LP, 0.15% caproic acid (LCA), 0.2% caproic acid (HCA), LCA + LP, and HCA + LP were employed for 30 days ensiling and an 8-days aerobic stability test. LP had similar pH value and lactic acid content with LCA + LP, while the contents of NH3-N and total VFAs in LCA + LP were significantly lower than those in LP and CON, and the fermentation quality of LCA + LP performed best among all silages. As air-exposure extended, contents of water-soluble carbohydrates (WSC), lactic, and acetic acids decreased, while pH, and NH3-N content increased significantly. The population of lactic acid bacteria gradually decreased in contrast to increased counts of aerobic bacteria and yeasts. Compared with LCA, 0.2% CA delayed the aerobic deterioration as judged by a slower increase in pH and high residual of WSC and lactic acid, and negligible ethanol content and anaerobe spores counts remained in HCA at the end of air exposure. Compared with CON (73 h), LP showed less aerobic stability (38 h), whereas HCA and HCA + LP prolonged aerobic stability for 210 and 152 h, better than LCA (109 h) and LCA + LP (146 h). CONCLUSIONS: Lactobacillus plantarum apparently improved the fermentation quality, and combined with CA exhibited greater efficiency in inhibiting undesirable microorganism during ensiling. CA at 0.2% optimally extended the aerobic stability.

Evaluation of molasses on fermentation profiles of wheat straw ensiled with tall fescue in the southwest Tibet.

Two experiments were carried out to determine the optimal proportion of mixed silage made with wheat straw and tall fescue, and further to evaluate the effects of molasses on fermentation quality. In Experiment 1, wheat straw and tall fescue were mixed at proportions of 10:0 (Control), 8:2 (WT20), 6:4 (WT40) and 4:6 (WT60) on fresh weight (FW) basis. Inclusion of tall fescue significantly (p < 0.05) increased lactic acid, water-soluble carbohydrate contents and ratio of lactic to acetic acid, and significantly (p < 0.05) decreased pH and contents of dry matter, NH3 -N and volatile fatty acids. WT60 had the highest (p < 0.05) lactic acid content, and the lowest (p < 0.05) pH and butyric acid content. In Experiment 2, the mixture of wheat straw and tall fescue (4/6) were treated with 0%, 3%, 4% and 5% molasses on FW basis (defined as control, WTM3, WTM4 and WTM5 respectively). Molasses addition significantly (p < 0.05) increased lactic acid and water-soluble carbohydrate contents, and significantly (p < 0.05) decreased pH and ammonia-nitrogen content as compared with control. Acetic acid content slightly (p > 0.05) decreased during ensiling, while trace amounts of propionic and butyric acids were observed. WTM5 had the lowest pH and the highest (p < 0.05) lactic acid, water-soluble carbohydrate contents and ratio of lactic to acetic acid at end of ensiling. In conclusion, the fermentation quality was maximally improved when the addition rate of molasses was 5% in 40% wheat straw ensiled with 60% tall fescue.

Effects of wet brewers grains on fermentation quality and in vitro ruminal digestibility of mixed silage prepared with corn stalk, sweet potato peel and dried apple pomace in southeast China.

The effects of wet brewers grains (WBG) on fermentation quality, chemical composition and in vitro ruminal digestibility of mixed silages prepared with corn stalk, dried apple pomace and sweet potato peel were evaluated. A mixture of corn stalk, sweet potato peel and dried apple pomace (50/30/20) was ensiled with 0, 10%, 20% and 30% WBG on a fresh weight (FW) basis for 1, 3, 5, 7, 14 and 30 days respectively. The results showed that the application of WBG increased (p < 0.05) lactic acid, acetic acid and total volatile fatty acids contents, and decreased (p < 0.05) pH, dry matter, water-soluble carbohydrates content and ammonia-nitrogen/total nitrogen during ensiling. The pH in all silages was below 4.03 during ensiling. Treating with WBG increased (p < 0.05) crude protein content, and decreased (p < 0.05) neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose content after 30 days of ensiling. After 72 h of incubation, cumulative gas production, potential gas production and in vitro crude protein digestibility increased (p < 0.05) with the increasing proportions of WBG. However, in vitro digestibility of dry matter and neutral detergent fibre, and metabolisable energy were similar in all silages. The 20% and 30% WBG-treated silages showed better fermentation quality and greater or higher in vitro digestibility, which were indicated by greater or higher (p < 0.05) lactic acid content, in vitro crude protein digestibility, and lower (p < 0.05) pH, ammonia-nitrogen/total nitrogen ratio as compared with the control. Therefore, ensiling agro-food by-products with at least 20% WBG were recommended for improving fermentation quality.

Assessment of organic acid salts on fermentation quality, aerobic stability, and in vitro rumen digestibility of total mixed ration silage.

The work aimed to investigate the effects of four organic acid salts on fermentation quality, aerobic stability, and in vitro rumen digestibility of total mixed ration (TMR) silage prepared with citric acid residue, wet brewers' grains, and Napier grass. The TMR was ensiled with the following: (1) no additives (control), (2) 0.1% sodium benzoate (SB), (3) 0.1% potassium sorbate (PS), (4) 0.5% sodium diacetate (SDA), (5) 0.5% calcium propionate (CAP) on a fresh weight basis. All silos (10 L) were opened after 60 days of ensiling to determine fermentation profiles and in vitro rumen digestibility, and then were subjected to a 9-day aerobic stability test. Four organic acid salts significantly (p < 0.05) increased dry matter contents, lactic acid bacteria count, and decreased ethanol content and yeast count compared with the control. The SDA and CAP significantly (p < 0.05) increased water-soluble carbohydrates, lactic acid, and crude protein contents, and decreased pH, ammonia nitrogen, neutral detergent fiber, and hemicellulose contents compared with other TMR silages after 60 days of ensiling. Organic acid salts significantly (p < 0.05) prolonged the hours of aerobic stability and significantly (p < 0.05) increased cumulative gas production and potential gas production compared with the control. The treatments of SDA and CAP significantly (p < 0.05) improved aerobic stability as indicated by higher (p < 0.05) lactic acid and water-soluble carbohydrates contents, and lower (p < 0.05) pH, ammonia nitrogen, ethanol contents, and yeast count compared with the control. The treatments of SDA and CAP significantly (p < 0.05) increased in vitro rumen parameters, as indicated by higher (p < 0.05) in vitro digestibility of dry matter, crude protein, and neutral detergent fiber after 60 days of ensiling. Overall, these results indicated that the addition of SDA and CAP could ensure the good fermentation quality and improve aerobic stability of TMR silages. By comprehensive consideration, CAP was recommended for improving fermentation quality, aerobic stability, and in vitro rumen digestibility of TMR silages prepared with wet brewers' grains, citric acid residue, and Napier grass.

GCK exonic mutations induce abnormal biochemical activities and result in GCK-MODY.

Objective: Glucokinase-maturity-onset diabetes of the young (GCK-MODY; MODY2) is a rare genetic disorder caused by mutations in the glucokinase (GCK) gene. It is often under- or misdiagnosed in clinical practice, but correct diagnosis can be facilitated by genetic testing. In this study, we examined the genes of three patients diagnosed with GCK-MODY and tested their biochemical properties, such as protein stability and half-life, to explore the function of the mutant proteins and identify the pathogenic mechanism of GCK-MODY. Methods: Three patients with increased blood glucose levels were diagnosed with MODY2 according to the diagnostic guidelines of GCK-MODY proposed by the International Society for Pediatric and Adolescent Diabetes (ISPAD) in 2018. Next-generation sequencing (whole exome detection) was performed to detect gene mutations. The GCK gene and its mutations were introduced into the pCDNA3.0 and pGEX-4T-1 vectors. Following protein purification, enzyme activity assay, and protein immunoblotting, the enzyme activity of GCK was determined, along with the ubiquitination level of the mutant GCK protein. Results: Genetic testing revealed three mutations in the GCK gene of the three patients, including c.574C>T (p.R192W), c.758G>A (p.C253Y), and c.794G>A (p.G265D). The biochemical characteristics of the protein encoded by wild-type GCK and mutant GCK were different, compared to wild-type GCK, the enzyme activity encoded by the mutant GCK was reduced, suggesting thermal instability of the mutant GST-GCK. The protein stability and expression levels of the mutant GCK were reduced, and the enzyme activity of GCK was negatively correlated with the levels of fasting blood glucose and HbA1c. In addition, ubiquitination of the mutant GCK protein was higher than that of the wild-type, suggesting a higher degradation rate of mutant GCK than WT-GCK. Conclusion: GCK mutations lead to changes in the biochemical characteristics of its encoded proteins. The enzyme activities, protein expression, and protein stability of GCK may be reduced in patients with GCK gene mutations, which further causes glucose metabolism disorders and induces MODY2.

Antimicrobial effects of four chemical additives on fermentation quality, aerobic stability, and in vitro ruminal digestibility of total mixed ration silage prepared with local food by-products.

The objective of the work is to evaluate the effects of four chemical additives on fermentation quality, aerobic stability, and in vitro ruminal digestibility of total mixed ration (TMR) silage. TMR containing 15% spent mushroom substrate, 25% soybean sauce residue, 45% napiergrass (Pennisetum purpureum (L.) Schum.), and 15% concentrate was ensiled with the following: (1) no additives (control), (2) potassium sorbate (PS, 0.1%), (3) sodium benzoate (SB, 0.1%), (4) sodium diacetate (SDA, 0.5%), and (5) calcium propionate (CAP, 0.5%) based on fresh weight. All silos (10 L) were opened for fermentation quality, in vitro ruminal digestibility analysis after 60 days of ensiling, and then subjected to aerobic stability test for 9 days. All TMR silages were well-conserved, as indicated by low pH, butyric acid, and ammonia nitrogen contents. During aerobic exposure, SDA was more stable with higher (p < 0.05) lactic acid and acetic acid contents and lower (p < 0.05) yeast counts than other TMR silages. In addition, SDA significantly (p < 0.05) increased cumulate gas production and in vitro dry matter digestibility compared with the control. Overall, SDA is recommended as additives to improve fermentation quality, in vitro ruminal digestibility, and aerobic stability of TMR silage prepared with local food by-products.