Rumen Bypass and Protection of Proteins and Amino Acids

Nitrogen and phosphorus nutrition of cattle: reducing the environmental impact of cattle operations.

Brassica napus L. is a vegetable oil crop, commonly known as rapeseed (or canola). It is widely used as a source of oil and protein for food and industrial applications, but also as a remedy, and in a field of attraction or as an ornament due to its diverse flower colors. Every part of rapeseed is useful, even the waste, which could be used to feed animals, or recycled. In this review, the use of rapeseed in these applications is presented, starting with the preparation of oil and protein from the seeds, before their release in the market, to the utilization of natural unprocessed rapeseed. Progress in rapeseed exploitation for food, remedy, energy source, and industrial applications are analyzed to show variability in diverse findings, to provide insights and progressive descriptions of rapeseed usage to other scholars. Moreover, advancements in breeding for rapeseed improvement were described. In the future, strategies could be developed or improved to avoid or decrease crop losses, but also to increase interest in propagating the valuable traits of rapeseed.

Rapeseed (Brassica napus): Processing, Utilization, and Genetic Improvement

Use of Plasma Amino Acid Concentration to Identify Limiting Amino Acids for Milk Production

The mixed buffer salts of artificial saliva were incorporated at three rates: 0 (diet 1), 5·7 (diet 2) and 11·4% (diet 3) (w/w) in pelleted diets prepared from60% ground flaked maize and 40% dried ground grass. The control and mineral-supplemented diets were fed to sheep hourly (Expt 1) or twice daily (Expt 2).When the sheep were fed hourly or twice daily the pattern of fermentation in the rumen was altered from a predominantly propionate to mainly acetate fermentation. Dilution rate in the rumen increased from 0·036 to 0·053 to 0·064 when diets 1, 2 and 3 were fed hourly, and dilution rate was negatively related to the molar proportion of propionic acid (P < 0·05) and positively related (P < 0·05) to the molar proportion of acetic acid in rumen fluid, but these relationships were not apparent in Expt 2.Nitrogen retention was higher for lambs fed diet 2 than for those fed diets 1 and 3 (P < 0·05) in Expt 1.In sheep fed hourly, selenomonads and bacteroides were the predominant rumen bacteria associated with the control diet but the inclusion of mineral salts resulted in the bacteroides being replaced by large number of chain-forming cocci. Numbers of protozoa were variable. The relationship of these changes to the fermentation pattern is discussed. In sheep fed twice daily there was much variation between animals.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0021859600056550

The effect of inclusion of mineral salts in the diet on dilution rate, the pattern of rumen fermentation and the composition of the rumen microflora

Merino sheep were given abomasal infusions of various amino acids or mixtures of amino acids. Effects on wool growth were measured using autoradiography or a clipping procedure and changes in the concentration of amino acids in plasma were measured in some experiments.Mixtures of five (28 g/day) or ten (45 g/day) essential amino acids (both mixtures containing 3 g methionine) stimulated wool growth of sheep receiving a maintenance ration; on average, the volume of wool grown increased 48% and 86%, respectively. When cysteine completely replaced methionine in these mixtures, wool growth was markedly reduced, but two-thirds of the methionine could be replaced by cysteine without affecting wool growth. Homocysteine was partially effective in replacing methionine and, when supplemented with betaine, folic acid and vitamin B12, the mixture was still significantly inferior to that containing methionine. In contrast, abomasal supplements of methionine or homocysteine alone were equivalent as supplements for wool growth. The results indicated a specific role for methionine in the control of wool growth, other than the provision of cysteine. This role was postulated to be related to some function of S-adenosylmethionine.Infusion often essential amino acids caused appreciable increases in the concentrations of cystine, methionine, cystathionine and taurine in plasma; total essential amino acids increased threefold whereas nonessential amino acids decreased in concentration. The replacement of methionine in the infusion by cysteine or homocysteine significantly altered the concentration of cystine, methionine and cystathionine in plasma.Evidence was obtained that the adverse effects on wool growth of high abomasal doses of methionine (10g/day) could not be reduced or prevented by provision of additional glycine and were not related to the supposed toxic effects of 3-methylthiopropionic acid, a metabolite of the transamination pathway.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0021859600071008

Effects of the infusion of amino acids into the abomasum of sheep, with emphasis on the relative value of methionine, cysteine and homocysteine for wool growth.

1. Doses of L-[35S]methionine (2 g) and [35S]casein (20 g) were given to sheep in the diet or via the abomasum, and the patterns of 35S-labelling in blood, wool and excreta were studied during the 7 d following administration of the dose.2. Doses given via the abomasum resulted in substantial labelling of the plasma proteins and wool; only small amounts of the dose were recovered in the urine and faeces. In contrast, doses given in the diet resulted in much less labelling of plasma proteins and wool and ingreater losses in excreta. These results provide the basis of a rapid system for testing the effectiveness of various methods of protecting methionine and casein from degradation in the rumen.3. From the patterns obtained with N-formyl-DL-[35S]methionine and [35S]polymethionine (mol. wt 7–8 × 104) it appears unlikely that these compounds would stimulate wool growth if given as dietary supplements.4. [35S]Casein which had been treated with an 8 % aqueous solution of formaldehyde gave results which showed that the casein had been protected from destruction in the rumen without markedly reducing its subsequent digestibility. Treatment of [35S]casein with excess, formalde-hyde (a 40 % aqueous solution) gave a product which was completely indigestible.5. It is concluded that the radioisotope technique could be applied to other [35S]amino acids or their derivatives and to other [35S]proteins, and should also be applicable to larger ruminants such as cattle.

/pdf/evaluation-of-modified-35s-methionine-and-35s-casein-2nxf6ok4c5.pdf

Evaluation of modified [35S] methionine and [35S]casein preparations as supplements for sheep.

Summary The fate of abomasal and intravenous doses of [35S]cystine and [35S]methionine was investigated in sheep to determine their relative efficacy as supplements for wool growth. Administration of L-[35S]cystine and L-, DL- and D-[35S]methionine via the abomasum produced similar patterns of 35S labelling in blood plasma. Only 10–16% of the administered 35S was excreted in urine over 7 days and 22–32% of the dose was incorporated into wool over 21 days. All isomers were utilized by the sheep with similar efficiency and it was concluded that D- and L-methionine and L-cystine are equally effective as supplements for wool growth at optimal dose rates. Abomasal supplementation with a large amount of methionine (10 g/day) resulted in the excretion of a high proportion of the 35S in urine (55% of the dose over 7 days) and low incorporation into wool. A comparison of the extent of incorporation of 35S into wool from intravenous doses of L-[35S]cystine and L-[35S]methionine in the same sheep, and in sheep from flocks selected for high and low wool production, showed that incorporation from methionine averaged 80% of that from cystine. It was concluded that, at moderate (2–3 g/day) methionine availability, methionine is utilized for synthesis of wool with about 80% of the efficiency of cystine, conversion of methionine to cysteine occurring via the transulphuration pathway.

Incorporation of abomasal and intravenous doses of [ 35 S]cystine and [ 35 S]methionine into wool

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Effects of the infusion of amino acids into the abomasum of sheep, with emphasis on the relative value of methionine, cysteine and homocysteine for wool growth.

Evaluation of modified [35S] methionine and [35S]casein preparations as supplements for sheep.

Incorporation of abomasal and intravenous doses of [ 35 S]cystine and [ 35 S]methionine into wool