A comparative study of the intestinal digestive characteristics of different feeds for Holstein cows

This experiment was conducted with lactating Chinese Holstein cows to study the nutritional value of local protein feed resources. A three-step method (TSP) and a modified three-step method (MTSP) were used to measure the in vitro digestibility of rumen undegraded protein (RUP) for 11 feedstuffs and correlation. Eleven experimental feeds were chosen and air-dried to investigate the effects of different growth periods and varieties on nutrition value and RUP digestibility. The small intestinal digestibility of RUP by TSP in concentrated feed was determined to be higher than that of roughage, approximately 65%. The highest concentrate (79%) was SBM (soybean mean), while the lowest was corn (65%). The proportions of DDGS (with soluble wine lees) and SFM (sunflower meal) were 70.9 and 74.9%, respectively. ASS (alfalfa mowed at the squaring stage) had the highest small intestinal digestibility of RUP (55%) among roughages, and WCS (whole-plant corn silage) had the lowest digestibility (40.5%). When the small intestinal digestibility of RUP was determined using the MTSP method, it exhibited similar results to the TSP method. Nevertheless, the values were generally higher, and there was a strong significant correlation between them (R2 = 0.967, P < 0.01). The comparative study of these two methods help us have a better understanding of small intestine digestibility of different feeds, make a reasonable feed formula to effectively prevent diseases.

Rumen fluid transplantation affects growth performance of weaned lambs by altering gastrointestinal microbiota, immune function and feed digestibility

Although rumen fluid transplantation (RT) has been developed to confer benefits for adult ruminants by altering gastrointestinal tract microbiota, the question remains whether RT can also benefit weaned lambs. Hence, in this study, thirty-eight pre-weaning lambs were randomly assigned to one of three treatment groups: control lambs (CON) received 25 ml of normal saline solution, and lambs in two RT groups received 25 ml of rumen fluid either from 3-month-old lambs (LT) or from one-year-old adult ewes (AT). The effects on their growth performance, nutrient digestibility, some blood parameters and gastrointestinal tract microbiota were monitored. There were differences (P < 0.05) in rumen bacterial composition between the groups at weaning, at 3 months and at 1 year. Rumen fluid transplantation decreased (P < 0.05) average daily feed intake, average daily gain in live weight and apparent digestibility of ether extract in the LT group, and it decreased (P < 0.05) apparent digestibility of NDF and ADF in the AT group. Rumen fluid transplantation also increased (P < 0.05) concentrations of serum immunoglobulin A in the AT group and increased (P < 0.05) serum concentrations of interleukin-6, interferon alpha and D-lactate in both LT and AT groups. Bacterial α-diversity in the rumen and rectum was not affected by RT (P > 0.05), but a bacterial community change was observed after RT, and the abundance of some dominant bacteria in both rumen and rectum changed after RT (P < 0.05). Analysis of correlations between the parameters indicated that the altered gastrointestinal microbiota and accelerated maturity of rumen microorganisms induced by RT caused some impairment of gastrointestinal integrity and immunity, which led to decreased feed intake, reduced feed digestibility and lower growth performance of the weaned lambs. In conclusion, rumen fluid transplantation altered the gastrointestinal microbiota causing adverse effects on feed intake, feed digestibility and growth performance of the weaned lambs.

Subacute ruminal acidosis affects fermentation and endotoxin concentration in the rumen and relative expression of the CD14/TLR4/MD2 genes involved in lipopolysaccharide systemic immune response in dairy cows

The first objective of this study was to investigate the effects of subacute ruminal acidosis (SARA) on fermentation, ruminal free lipopolysaccharides (LPS), and expression of the cluster of differentiation 14 (CD14), toll-like receptor 4 (TLR4), and myeloid differentiation protein 2 (MD2) complex in white blood cells involved in the systemic immune response in dairy cows. The second objective was a study of whether increased expression of the LPS receptor complex led to increases in the concentrations of plasma high-density lipoprotein (HDL) and serum Ca. Three hundred five dairy cows located in 13 Polish high-yielding dairy commercial farms were selected according to their days in milk (40-150 d; average = 75), 305-d milk yield (10,070-12,041 kg; average = 10,940), and number of lactations (primiparous, n = 139 and multiparous, n = 166). Next, the herds were segregated into 3 groups based on the percentages of cows with an assigned value of ruminal fluid pH: SARA-positive, SARA-risk, and SARA-negative herds. Moreover, 305 selected dairy cows were divided according to the classification based on ruminal fluid pH into 3 groups as healthy (pH >5.81), risk (pH 5.8-5.6) and acidotic cows (pH <5.6). Rumen fluid samples were collected via rumenocentesis. In the AC group, we recorded higher concentrations of ruminal free LPS [4.57 Log₁₀ endotoxin units (EU)/mL; 42,206 EU/mL] compared with the healthy group (4.48 Log₁₀ EU/mL; 34,179 EU/mL). Similarly, the concentration of ruminal free LPS was higher in SARA-positive herds (4.60 Log₁₀ EU/mL; 43,000 EU/mL) compared with SARA-negative herds (4.47 Log₁₀ EU/mL; 32,225 EU/mL). The relative mRNA abundance of genes associated with the function of LPS receptors, such as CD14, TLR4, and MD2, in white blood cells differed between all experimental groups on both cow and herd levels. In the acidotic group, we recorded higher concentrations of HDL (78.16 vs. 68.32 mg/dL) and serum amyloid A (10.80 vs. 9.16 µg/mL) and lower concentrations of Ca (8.26 vs. 10.16 mg/dL) and haptoglobin (470.19 vs. 516.85 ng/mL) compared with the healthy group. Similar results were obtained in the SARA herd status analysis, but the concentration of lipopolysaccharide-binding protein differed statistically. Moreover, the pH of ruminal fluid was negatively correlated with relative mRNA abundance of genes such as CD14, TLR4, MD2, and concentrations of serum HDL and serum amyloid A, although positively correlated with serum Ca. The results indicated that decreases in ruminal fluid pH increased the release of free LPS into the rumen and stimulated the expression of the LPS receptor complex and immune response. Moreover, an increase in the expression of the LPS receptor led to higher concentrations of plasma HDL and lower serum Ca, which may be a protective mechanism against endotoxemia. However, the biological significance of these results needs to be investigated further in larger field trials.