Effects of Feeding Oxalate Containing Grass on Intake and the Concentrations of Some Minerals and Parathyroid Hormone in Blood of Sheep

Effects of yeast culture and oxalic acid supplementation on in vitro nutrient disappearance, rumen fermentation, and bacterial community composition

Hemicellulose is an important polysaccharide in ruminant nutrition, but it has not been studied as thoroughly as cellulose. Further research is needed to explore supplements that can improve its digestibility and ruminal buffering effects. Our previous research demonstrated the efficacy of oxalic acid (OA) as an essential nutrient in yeast culture (YC) for improving rumen fermentation performance. Consequently, we conducted in vitro rumen digestion experiments to examine the effects of YC and OA on rumen fermentation and bacterial composition. Two diets containing different levels of hemicellulose were formulated: diet 1 with 10.3% and diet 2 with 17% hemicellulose. Three levels of YC (0.00, 0.625, and 1.25 g/kg) and three doses of OA (0.0, 0.4, and 0.8 g/kg, DM) were added into each diet with a 3 × 3 factorial design. A comprehensive assessment was conducted on a total of 18 experimental treatments at fermentation periods of 0, 6, 12, 24, and 48 h. In the first experiment (diet 1), the supplementation of YC, OA, and their interaction significantly increased in vitro DM disappearance (IVDMD) and NDF disappearance (IVNDFD; p < 0.001). In the second experiment (diet 2), the supplementation of OA and the interaction between YC and OA (p < 0.001) increased IVDMD and IVCPD, but had no significant effects on IVNDFD. The interactions of YC and OA significantly increased ammonia nitrogen (p < 0.001). The production of acetic acid, propionic acid, and total volatile fatty acids (TVFA), and pH levels were significantly higher in treatments supplemented with YC and OA (p < 0.001). YC and OA in both diets significantly altered the rumen bacterial community leading to increased Shannon and Simpson diversity indices (p < 0.001). In both diets, OA supplementation significantly increased the relative abundance of the phylum Bacteroidetes and Prevotella genus. The result also showed a positive correlation between the Prevotella and Selenomonas genera with IVDMD, IVNDFD, propionic acid, and TVFA production, suggesting that these dominant bacteria enhanced nutrient disappearance in the rumen. In conclusion, adding YC and OA resulted in modifications to the bacterial community's composition and diversity, and improved nutrient disappearance. These changes indicate improved rumen fermentation efficiency, which is promising for future in vivo studies.

Potential of Mulberry Leaf Biomass and Its Flavonoids to Improve Production and Health in Ruminants: Mechanistic Insights and Prospects

Leaf biomass from the mulberry plant (genus Morus and family Moraceae) is considered a potential resource for livestock feeding. Mulberry leaves (MLs) contain high protein (14.0-34.2%) and metabolizable energy (1130-2240 kcal/kg) with high dry matter (DM) digestibility (75-85%) and palatability. Flavonoid contents of MLs confer unique antioxidant properties and can potentially help alleviate oxidative stress in animals during stressful periods, such as neonatal, weaning, and periparturient periods. In addition, mulberry leaf flavonoids (MLFs) possess antimicrobial properties and can effectively decrease the population of ruminal methanogens and protozoa to reduce enteric methane (CH4) production. Owing to its rich flavonoid content, feeding MLs increases fiber digestion and utilization leading to enhanced milk production in ruminants. Dietary supplementation with MLFs alters ruminal fermentation kinetics by increasing total volatile fatty acids, propionate, and ammonia concentrations. Furthermore, they can substantially increase the population of specific cellulolytic bacteria in the rumen. Owing to their structural homology with steroid hormones, the MLFs can potentially modulate different metabolic pathways particularly those linked with energy homeostasis. This review aims to highlight the potential of ML and its flavonoids to modulate the ruminal microbiome, fermentation, and metabolic status to enhance productive performance and health in ruminants while reducing CH4 emission.

Feed utilization and lactational performance of Friesian cows fed beet tops silage treated with lactic acid bacteria as a replacement for corn silage

Thirty multiparous lactating Friesian cows were used to study the effect of partial or complete replacement of corn silage with lactic acid bacteria (LAB), molasses and calcium carbonate ensiled sugar beet tops for 3 months in a complete randomized experimental design with repeated measures. A week after parturition, cows were grouped into three treatments of 10 cows each and fed a control treatment containing corn silage at 300 g/kg DM. In the other treated diets, 50% or 100% of the control corn silage was substituted with beet tops silage treated with LAB included at 150 g or 300 g per kg diet. Ensiling of beet tops with LAB decreased its contents of oxalic acid and neutral detergent and acid detergent fibers but increased its contents of non-structural carbohydrate and calcium. Without affecting daily milk production and feed efficiency, beet tops silage treated with LAB diets decreased (p < 0.05) feed intake, total ruminal volatile fatty acids, acetate and propionate concentrations, energy-corrected milk yield and concentrations of milk total solids, fat, protein and energy. In conclusion, beet tops silage treated with LAB can replace corn silage in diets of lactating cows. An inclusion rate of 15% of beet tops silage treated with LAB (replacing 50% of corn silage) in the diet was the most suitable level for lactating cows under the current experimental conditions.