Ruminal Biohydrogenation Kinetics of Defatted Flaxseed and Sunflower Is Affected by Heat Treatment

Jensen

et al. 2018

J. Agric. Food Chem.

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Soluble protein extracted from leaves and stems of grasses and forage legumes is defined as green protein. The present study was conducted to evaluate in situ green protein degradability, intestinal protein disappearance, and in vitro fatty acids biohydrogenation (BH) in dairy cows. Three green protein concentrates (red clover, ryegrass, and grass clover) were heat treated as follows: oven-drying at 70 °C, subsequent autoclaving at 121 °C for 45 min, and for grass clover also spin flash-drying. Freeze-dried green protein was considered as a control (untreated). Autoclaving and oven-drying of green protein reduced the crude protein and dry matter degradability. The linolenic acid BH rate was lowest in heat-treated grass clover concentrate ( P < 0.01). In conclusion, green proteins are heat sensitive, and oven-drying can be an appropriate method to increase the amount of protein and unsaturated fatty acids escaping from the rumen.

Section: ■ Resultssupporting

confidence: 93%

“…However, the disappearance rate of LA was not affected by heat treatments, and it seems that response to heat treatment depends on type of PUFA. In agreement with our results, Lashkari et al reported the different responses of LA vs LNA in heat-treated defatted flaxseed and sunflower. The different responses of LA vs LNA were most likely due to a partly different location of LA and LNA in the plant.…”

Section: Discussionsupporting

confidence: 94%

Effects of Heat Treatment of Green Protein on in Situ Protein Disappearance and in Vitro Fatty Acid Biohydrogenation

Chowdhury

Jensen

et al. 2018

J. Agric. Food Chem.

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“…The high V max value in both FFA_LNA and FFA_LA may be due to reduced adverse effects of free PUFA (Lashkari et al, ). It is well established that free PUFA are more toxic than esterified PUFA to the function of rumen bacteria; therefore, the microbes biohydrogenate PUFA to avoid the toxic effect (Choi et al, ).…”

Section: Discussionmentioning

confidence: 99%

Rumen biohydrogenation of linoleic and linolenic acids is reduced when esterified to phospholipids or steroids

Food Science & Nutrition

Petersen²,

Jensen

2019

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Manipulation of rumen biohydrogenation (BH) is of great importance, since decreased BH of linolenic acid (LNA) and linoleic acid (LA) is linked to increased content of the beneficial polyunsaturated fatty acids (PUFA) in dairy products and decreased content of trans fatty acids (FAs). We hypothesized that PUFA esterified to the complex lipid fractions are less prone to BH compared with PUFA esterified to the simple lipid fractions due to reduced lipolysis. In vitro rumen BH of different single lipid fractions was investigated, including free fatty acids (FFA), and esterified FA to triglycerides (TG), cholesterol esters (CE), and phospholipids (PL). A mixture of a buffer solution and rumen fluid was incubated with different lipid fractions, and C18 FAs were quantified by gas chromatography. In vitro BH kinetic parameters were quantified according to Michaelis–Menten equation and the maximum BH (Vmax) and time to achieve 50% of maximum amount (KM) estimated. Regardless of fatty acids, BH in CE and PL was lower than FFA and TG. The highest amount of cis‐9, trans‐11 conjugated linoleic acid (CLA) and trans‐10, cis‐12 CLA was observed in lipid fractions containing LA and LNA, respectively, regardless of lipid fractions. The present study demonstrates the importance of lipid fractions on BH of LNA and LA and formation of CLA isomers. The results show that BH of FAs depends on the lipid fractions.

“…To analyse FA profile, fat was extracted according to Bligh and Dyer (Fat BD ; Bligh & Dyer, ) after hydrolysing the samples with HCl. Fatty acids were methylated with NaOH in methanol and boron trifluoride and quantified by gas chromatography (Lashkari, Hymøller, & Jensen, ).…”

Section: Methodsmentioning

confidence: 99%

Effect of oat decortication on chemical composition, in vitro digestibility and in situ degradability

Panah

Animal Physiology Nutrition

Weisbjerg

2019

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The effect of decortication on chemical composition and degradability characteristics of four Danish oat varieties was investigated. Effective degradability (ED) and post‐ruminal disappearance (PRD) were measured by in situ and mobile bag techniques respectively. Decorticated oat showed higher (p = .01) concentrations of crude protein (CP; 134 vs. 108 g/kg DM) and crude fat (71.6 vs. 53.1 g/kg DM) and a higher (p = .001) organic matter digestibility (OMD; 888 vs. 703 g/kg OM) than oat. The content of total fatty acids (FA) in DM was higher in decorticated oat. The proportion of linoleic acid (C18:2 n6) increased (p < .05) due to decortication, while the linolenic acid (C18:3 n3) proportion of total FA decreased in decorticated oat. Decortication increased (p = .01) the concentration of amino acids (AA), but the proportion of lysine in total AA decreased (p < .002). Effective degradability (ED) of both DM and CP was (p < .001) higher in decorticated oat. Decortication increased the total tract disappearance (TTD) and PRD of CP (p < .001). In conclusion, decortication can be used as a practical approach to increase the nutritional value of oat.