Dietary fenugreek seed extract improves dry matter intake, apparent total tract nutrient digestibility, and alters whole blood transcriptome of Holstein dairy heifers

Abstract

This study was conducted to evaluate the effects of dietary supplementation of a fenugreek seed extract (SAP) as a source of saponins on dry matter intake, blood metabolites, apparent total-tract nutrient digestibility, and whole blood transcriptome of Holstein dairy heifers. Eight (8) heifers (BW = 477 ± 23.8 kg) were stratified by BW and then randomly assigned to 1 of 2 treatments in a cross-over design with two 35-day experimental periods and a 14-d wash-out between the two periods. The heifers were housed individually in 8 dry lot pens. Each pen was equipped with one GrowSafe intake node. Treatments were 1) corn silage-based diet with no additive (CON) and 2) corn silage-based diet plus 2 g/hd/day of SAP. Dairy heifers fed supplemental SAP had higher (P ≤ 0.05) DMI and apparent total-tract digestibility of dry matter, crude protein, and neutral detergent fiber compared to CON. Dairy heifers fed supplemental SAP had lower (P = 0.03) blood urea nitrogen and higher (P = 0.01) blood glucose concentration compared to CON. Pathway analysis via gene set enrichment analysis (GSEA) revealed increased (FDR ≤ 0.05) transcript levels for gene sets belonging to ISG15 antiviral mechanism, metabolism of proteins, citric acid cycle and respiratory electron transport, ATP synthesis by chemiosmotic coupling, and complex I biogenesis in dairy heifers fed supplemental SAP compared to CON. Decreased (FDR ≤ 0.05) transcript levels for gene sets associated with erythrocytes take up/release carbon dioxide, release/take up oxygen, and O2/CO2 exchange in erythrocytes were also observed with SAP supplemental group. Taken together, our results revealed that fenugreek seed extract can be used as an effective dietary supplement for dairy heifers to improve intake and digestibility, and alter the host transcriptome towards improved energy and amino acid metabolism, improved antiviral immune status and reduced oxidative stress damage.

A Review of Effect of Saponins on Ruminal Fermentation, Health and Performance of Ruminants

“…Positive effects of saponins or saponins-containing plants on nutrient digestibility were reported [ 13 , 35 , 68 ]. Kim et al [ 30 ] showed increased in vitro DM degradability and insignificant effects on NDF and protein degradability with the administration of A. saponaria .…”

“…Liu et al [ 35 ] showed that feeding ewes on diet supplemented with tea saponins at 2 g/ewe/day enhanced the in vivo digestibility of OM, NDF, and ADF. Recently, Taiwo et al [ 68 ], using saponins extracted from fenugreek seed, noted increased DM, CP, NDF, and ADF digestibility in steers. The positive effects of saponins on nutrient digestibility indicate the ability of saponins to alter the site of digestion in the gastrointestinal tract [ 9 ], which possibly improves feed degradation in the rumen.…”

“…Abdullah and Al-Galbi [ 77 ] showed that feeding saponins from tea leaves at 180 mg/kg DM increased blood glucose and protein concentrations without affecting cholesterol. Recently, Taiwo et al [ 68 ] observed lowered concentrations of blood urea and glucose when feeding with a saponins-containing fenugreek seed extract to steers. Moheghi et al [ 32 ] reported that feeding with a basal diet consisting of forage (30%), concentrates (70%), and saponins (150 mg/kg DM) to Baluchi lambs had a marginal effect on the concentrations of glucose, blood urea N, total protein, triglycerides, cholesterol, packed cell volume, total protein, and hemoglobin, but increased the count of total white blood cells.…”

“…Other experiments showed slight decreases in feed consumption ranging from 2 to 6% [ 36 , 39 ], resulting in lowered milk production efficiency. However, some experiments showed increased feed intake when feeding with saponins [ 68 ]. It should be emphasized that the weak effect of saponins on milk production and composition may be related to using low doses of saponins.…”

Blood Transcriptome Analysis Provides Responsive Changes in Gene Expression between Ex Situ and Captive Yangtze Finless Porpoises (Neophocaena asiaeorientalis asiaeorientalis)

“…In addition to COL4A1 and COL4A2, which also affect the digestive function through the regulation of the blood supply to the digestive organs [46]. And similar studies by Taiwo (2002) found that feeding fenugreek seed extract significantly up-regulated the protein metabolism-related genes in the blood of dairy heifers, resulting in improved energy and amino acid metabolisms, as well as an increased feed intake and digestibility [47]. And our enrichment analysis found that these genes were enriched in the digestive system pathways, such as protein digestion and absorption, gastric acid secretion, and pancreatic secretion, which may indicate that the protein digestive function of the controlled environment population improved.…”