Effect of thermal processing on estimated metabolizable protein supply to dairy cattle from camelina seeds: relationship with protein molecular structural changes

Effect of growing regions on morphological characteristics, protein subfractions, rumen degradation and molecular structures of various whole-plant silage corn cultivars

Little information exists on the variation in morphological characteristics, nutritional value, ruminal degradability, and molecular structural makeup of diverse whole-plant silage corn (WPSC) cultivars among different growing regions. This study investigated the between-regions (Beijing, Urumchi, Cangzhou, Liaoyuan, Tianjin) discrepancies in five widely used WPSC cultivars in China (FKBN, YQ889, YQ23, DK301 and ZD958), in terms of 1) morphological characteristics; 2) crude protein (CP) chemical profile; 3) Cornell Net Carbohydrate and Protein System (CNCPS) CP subfractions; 4) in situ CP degradation kinetics; and 5) CP molecular structures. Our results revealed significant growing region and WPSC cultivar interaction for all estimated morphological characteristics (P < 0.001), CP chemical profile (P < 0.001), CNCPS subfractions (P < 0.001) and CP molecular structural features (P < 0.05). Except ear weight (P = 0.18), all measured morphological characteristics varied among different growing regions (P < 0.001). Besides, WPSC cultivars planted in different areas had remarkably different CP chemical profiles and CNCPS subfractions (P < 0.001). All spectral parameters of protein primary structure of WPSC differed (P < 0.05) due to the growing regions, except amide II area (P = 0.28). Finally, the area ratio of amide I to II was negatively correlated with the contents of soluble CP (δ = -0.66; P = 0.002), CP (δ = -0.61; P = 0.006), non-protein nitrogen (δ = -0.56; P = 0.004) and acid detergent insoluble CP (δ = -0.43; P = 0.008), in conjunction with a positive correlation with moderately degradable CP (PB1; δ = 0.58; P = 0.01). In conclusion, the cultivar of DK301 exhibited high and stable CP content. The WPSC planted in Beijing showed high CP, SCP and NPN. The low rumen degradable protein of WPSC was observed in Urumchi. Meanwhile, above changes in protein profiles and digestibility were strongly connected with the ratio of amide I and amide II.

Evaluation of the nutritional value of faba beans with high and low tannin content for use as feed for ruminants

BACKGROUND

Faba bean varieties with low or zero tannin content have been developed in Canada to overcome the negative effects of condensed tannins on the utilization by ruminants of crude protein (CP) and starch. However, their nutritional value has not been evaluated for incorporation in dairy rations. The objectives of this study were to investigate (i) the chemical profile; (ii) the Cornell Net Carbohydrate and Protein System (CNCPS) protein and carbohydrate subfractions; (iii) the energy values; (iv) the ruminal, intestinal, and total digestibility of CP; (v) the metabolizable protein (MP) supply to dairy cows; and (vi) the protein-inherent molecular spectral characteristics of brown-seeded (var. Fatima) faba beans with high tannin content and yellow-seeded (var. Snowbird) faba beans with low tannin content.

RESULTS

The results revealed that Fatima beans had higher (P < 0.001) CP content than Snowbird (324 versus 295 g kg^-1 dry matter (DM)), and lower (P < 0.01) starch content than Snowbird (411 g kg^-1 DM versus 444 g kg^-1 DM). Fatima had a lower (P = 0.001) soluble subfraction (201 g kg^-1 DM versus 220 g kg^-1 DM) and higher (P < 0.05) slowly degradable fiber-bounded (24.9 g kg^-1 DM versus 14.7 g kg^-1 DM) and non-degradable (3.24 g kg^-1 DM versus 0 g kg^-1 DM) CNCPS CP subfractions than Snowbird. Fatima had higher (P = 0.03) MP content (117 g kg^-1 DM versus 111 g kg^-1 DM) and metabolizable energy content (ME) 3.12 Mcal kg^-1 versus 3.10 Mcal kg^-1 ) than Snowbird. Molecular spectral intensities of amide I and II proteins (height and area) of Fatima were higher (P < 0.05) than those of Snowbird, reflecting their higher CP content. The ratio of protein spectral intensities, the amide I : amide II height ratio, and the α-helix : β-sheet height ratio differed (P < 0.05) between the two types of bean, highlighting differences in their inherent protein molecular structures.

CONCLUSION

The (Fatima) faba beans with high condensed tannin content had higher MP and ME content. On average, both Faba beans had higher ME and MP content than barley grains, highlighting their promising nutritional value for dairy rations. © 2021 Society of Chemical Industry.

Using advanced vibrational molecular spectroscopy (ATR-Ft/IRS) to study heating process induced changes on protein molecular structure of biodegradation residues in cool-climate adapted faba bean seeds: Relationship with rumen and intestinal protein digestion in ruminant systems

The objective of this study was to evaluate the effects of heating process on protein molecular structure from ruminal degradation residues in cool-climate adapted faba bean seeds in relation to crude protein (CP), in situ degradation kinetics, rumen protein degradation and intestinal protein digestion parameters in dairy cows. Seeds of six faba bean varieties with low (Snowbird, Snowdrop, 219_16) and normal tannin (Fatima, 346_10, SSNS_1) were collected from three different locations, and were heated 3 min by microwave irradiation (MI, dry heating) or heated 1 h by steam pressure toasting (SP, moist heating) or kept raw as a control. Heat treated samples were used for rumen incubating 24, 12, 8, 4, 2, 0 h(s) in two replicate runs and then residues from 12 h of rumen degradation were used for three steps in vitro technique for determining intestinal protein digestion. Attenuated total reflectance Fourier transforms infrared spectroscopy (ATR-Ft/IRS) was used for analyzing protien molecular structure of residual faba bean seeds. The results showed that SP increased the intensities of amide I, amide II, α-helix and β-sheet but decreased amide I to amide II height and area ratio, α-helix to β-sheet height ratio from 12 and 24 h of ruminal degradation, and MI decreased all the intensities of amide I, amide II, α-helix and β-sheet and ratios except amide I to amide II area ratio of residues from 24 h of ruminal degradation. Additionally, the intensities of amide I, amide II, α-helix and β-sheet had a unique pattern of increasing first and then decreasing with the increasing ruminal digestion time for SP treatment, while amide I to amide II height and area ratio, α-helix to β-sheet height ratio were declining. For the MI groups, this pattern was not observed and the intensities were rather consistent across the digestion process. Rumen protein degradation parameters including rumen bypass crude protein (BCP) or rumen undegradable protein (RUP) and rumen degradable protein (RDP) closely correlated with protein molecular structure of to peak heights, areas and ratios. Regression equations based on residual protein molecular structure presented a good estimation power for soluble fraction (S, R² = 0.79), degradable fraction (D, R² = 0.805), BCP (R² = 0.941), RUP (R² = 0.941) and RDP (R² = 0.811). Overall, heat-induced changes in rumen residual protein molecular structures were related to CP, in situ degradation kinetics, rumen protein degradation and rumen protein digestion parameters.

Molecular spectroscopic features of protein in newly developed chickpea: Relationship with protein chemical profile and metabolism in the rumen and intestine of dairy cows

The first aim of this study was to investigate the nutritional value of crude protein (CP) in CDC [Crop Development Centre (CDC), University of Saskatchewan] chickpea varieties (Frontier kabuli and Corinne desi) in comparison with a CDC barley variety in terms of: 1) CP chemical profile and subfractions; (2) in situ rumen degradation kinetics and intestinal digestibility of CP; 2) metabolizable protein (MP) supply to dairy cows; and (3) protein molecular structure characteristics using advanced molecular spectroscopy. The second aim was to quantify the relationship between protein molecular spectral characteristics and CP subfractions, in situ rumen CP degradation characteristics, intestinal digestibility of CP, and MP supply to dairy cows. Samples (n=4) of each variety, from two consecutive years were analyzed. Chickpeas had higher (P<0.01) CP content (21.71-22.11 vs 12.96% DM), with higher (P<0.05) soluble CP subfraction (59.07-70.27 vs 26.18% CP), and in situ soluble (23.44-25.85 vs 1.30% CP) and rumen degradable (RDP; 72.23-72.57 vs 58.48% CP) fractions than barley. The potentially slowly rumen degradable (D; 74.14-76.56 vs 93.31% CP) and undegradable (RUP; 27.43-27.66 vs 41.52% CP) fractions were lower (P<0.01) in the chickpeas than barley. The effective degradability ratio of N to organic matter (OM) (36.07-38.44gN/kg OM) of the chickpeas was higher than the optimal for achieving optimum microbial CP (MCP) synthesis. The truly digested MCP (64.94-66.43 vs. 41.43g/kg DM); MP (81.10-83.67 vs 61.0g/kg DM) feed milk value (1.64-1.70 vs 1.24) was higher in the chickpeas than barley grain. The chickpeas had higher (P<0.05) amide I and II peaks area and height, and α-helix and β-sheet peaks height than barley. Multivariate analysis showed that protein molecular spectral data of chickpeas can be distinguished from the barley. The two chickpeas did not differ in CP content, and any of the measured in situ degradation and molecular spectral characteristics of protein. The content of RUP was positively (r=0.94, P<0.01) and that of RDP was negatively (r=-0.94, P<0.01) correlated with amide I/II area ratio. The regression analysis showed that the content of CP (R2=0.91) D-fraction (R²=0.82), RDP (R²=0.77), RUP (R²=0.77), TDP (R²=0.98), MP (R²=0.80), and FMV (R²=0.80) can be predicted from amide II peak height. Despite extensive ruminal degradation, chickpea is a good source of MP for dairy cows, and molecular spectroscopy can be used to rapidly characterize feed protein molecular structures and predict their digestibility and nutritive value.

Relationship between protein molecular structural makeup and metabolizable protein supply to dairy cattle from new cool-season forage corn cultivars

Protein solubility, ruminal degradation and intestinal digestibility are strongly related to their inherent molecular makeup. This study was designed to quantitatively evaluate protein digestion in the rumen and intestine of dairy cattle, and estimate the content of truly metabolizable protein (MP) in newly developed cool-season forage corn cultivars. The second objective was to quantify protein inherent molecular structural characteristics using advance molecular spectroscopic technique (FT/IR-ATR) and correlate it to protein metabolic characteristics. Six new cool-season corn cultivars, including 3 Pioneer (PNR) and 3 Hyland (HL), coded as PNR-7443R, PNR-P7213R, PNR-7535R, HL-SR06, HL-SR22, HL-BAXXOS-RR, were evaluated in the present study. The metabolic characteristics, MP supply to dairy cattle, and energy synchronization properties were modeled by two protein evaluation models, namely, the Dutch DVE/OEB system and the NRC-2001 model. Both models estimated significant (P<0.05) differences in contents of microbial protein (MCP) synthesis and truly absorbable rumen undegraded protein (ARUP) among the cultivars. The NRC-2001 model estimated significant (P<0.05) differences in MP content and degraded protein balance (DPB) among the cultivars. The contents MCP, ARUP and MP were higher (P<0.05) for cultivar HL-SR06, resulting in the lowest (P<0.05) DPB. However, none of the cultivars reached the optimal target hourly effective degradability ratio [25gNg/kg organic matter (OM)], demonstrating N deficiency in the rumen. There were non-significant differences among the cultivars in molecular-spectral intensities of protein. The amide I/II ratio had a significant correlation with ARUP (r=-0.469; P<0.001) and absorbable endogenous protein (AECP^NRC) (P<0.001; r=0.612). Similarly, amide-II area had a weak but significant correlation (r=0.299; P<0.001) with RUP and ARUP, and with AECP^NRC (P<0.001; r=0.411). Except total digestible nutrients and AECP^NRC, the amide-I area did not show significant correlations with DVE/OEB and NRC predicted protein fractions. This study shows that molecular spectroscopy can be potentially used as a rapid tool to quantify protein molecular makeup and screen the protein nutritive value of forage corn.

Estimating total lipid content of Camelina sativa via pyrolysis assisted in-situ transesterification with dimethyl carbonate

Direct derivatization of C. sativa seed into FAMEs without lipid extraction was conducted for the quantification of lipid analysis via in-situ thermal methylation with dimethyl carbonate as an acyl acceptor on silica (SiO₂). The introduced method had an extraordinarily high tolerance against impurities such as pyrolytic products and moisture. To ensure the technical completeness of in-situ methylation, thermal cracking of FAMEs transformed from C. sativa seed was also explored. Thermal cracking of unsaturated FAMEs such as C_18:1, C_18:2, C_18:3 and C_20:1 occurred at temperatures higher than 365°C due to their thermal instability. Thus, experimental findings in this study suggests not only that qualitative analysis of fatty acid profile in C. sativa seed via in-situ methylation using SiO₂ could be achieve, but also that the total lipid content (42.65wt.%) in C. sativa seed could be accurately estimated.

Truly Absorbed Microbial Protein Synthesis, Rumen Bypass Protein, Endogenous Protein, and Total Metabolizable Protein from Starchy and Protein-Rich Raw Materials: Model Comparison and Predictions

This study was carried out to measure truly absorbed microbial protein synthesis, rumen bypass protein, and endogenous protein loss, as well as total metabolizable protein, from starchy and protein-rich raw feed materials with model comparisons. Predictions by the DVE2010 system as a more mechanistic model were compared with those of two other models, DVE1994 and NRC-2001, that are frequently used in common international feeding practice. DVE1994 predictions for intestinally digestible rumen undegradable protein (ARUP) for starchy concentrates were higher (27 vs 18 g/kg DM, p < 0.05, SEM = 1.2) than predictions by the NRC-2001, whereas there was no difference in predictions for ARUP from protein concentrates among the three models. DVE2010 and NRC-2001 had highest estimations of intestinally digestible microbial protein for starchy (92 g/kg DM in DVE2010 vs 46 g/kg DM in NRC-2001 and 67 g/kg DM in DVE1994, p < 0.05 SEM = 4) and protein concentrates (69 g/kg DM in NRC-2001 vs 31 g/kg DM in DVE1994 and 49 g/kg DM in DVE2010, p < 0.05 SEM = 4), respectively. Potential protein supplies predicted by tested models from starchy and protein concentrates are widely different, and comparable direct measurements are needed to evaluate the actual ability of different models to predict the potential protein supply to dairy cows from different feedstuffs.

Effect of Heating Method on Alteration of Protein Molecular Structure in Flaxseed: Relationship with Changes in Protein Subfraction Profile and Digestion in Dairy Cows

This study evaluated the effect of heating methods on alteration of protein molecular structure in flaxseed (Linum usitatissimum L.) in relation to changes in protein subfraction profile and digestion in dairy cows. Seeds from two flaxseed varieties, sampled from two replicate plots at two locations, were evaluated. The seeds were either maintained in their raw state or heated in an air-draft oven (dry heating) or autoclave (moist heating) for 60 min at 120 °C or by microwave irradiation (MIR) for 5 min. Compared to raw seeds, moist heating decreased (P < 0.05) soluble protein (SP) content [56.5 ± 5.55 to 25.9 ± 6.16% crude protein (CP)] and increased (P < 0.05) rumen undegraded protein (RUP) content (36.0 ± 5.19 to 46.9 ± 2.72% CP) and intestinal digestibility of RUP (61.0 ± 2.28 to 63.8 ± 2.67% RUP). Dry heating did not alter (P > 0.05) the protein subfraction profile and rumen degradation kinetics, whereas MIR increased (P < 0.05) the RUP content from 36.0 ± 5.19 to 40.4 ± 4.67% CP. The MIR and dry heating did not alter (P > 0.05) the amide I to amide II ratio, but moist heating decreased (P < 0.05) both the amide I to amide II ratio and α-helix-to-β-sheet ratio. Regression equations based on protein molecular spectral intensities provided high prediction power for estimation of heat-induced changes in SP (R² = 0.62), RUP (R² = 0.71), and intestinal digestibility of RUP (R² = 0.72). Overall, heat-induced changes in protein nutritive value and digestion were strongly associated with heat-induced alteration in protein molecular structures.