Rumen microbial protein flow and plasma amino acid concentrations in early lactation multiparity Holstein cows fed commercial rations, and some relationships with dietary nutrients

Swanepoel, N.; Robinson, Paul H.; Erasmus, L.J.

doi:10.1016/j.livsci.2016.06.001

Cited by 19 publications

(22 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is consistent with the reduction in plasma concentrations of Leu (P=0.01) and the tendency for Tyr concentrations to decrease (P=0.07) with higher CM inclusion in the current study. When compared to the plasma AA indices of Swanepoel et al (2016b), Tyr concentrations for the HCM diet was below 20 th percentile of measured data, suggesting that it could be potentially limiting, which is consistent with previous findings and our objective. However, even with Phe concentrations in the HCM diet below the 20 th percentile, the lack of a reduction in plasma Phe concentrations due to feeding the HCM versus LCM diet suggests that supplementing Phe to the HCM diet in order to regain potentially lost BCS (as suggested in Swanepoel et al, 2016a) was unnecessary.…”

Section: Low CM Versus High Cm Diets Without Phe or Tyr Supplementationsupporting

confidence: 91%

“…Phe was supplemented to the HCM diet (HCM+P), both plasma Phe and Tyr concentrations increased, with Phe concentrations approaching the 80 th percentile of its AA index (Swanepoel et al, 2016b), suggesting possible oversupply of these AA. That these plasma AA increases were associated with a reduction of milk protein content and yield, in addition to the already lower milk components for the HCM versus LCM fed cows, and with continued higher PUN concentrations, suggests that many AA were not utilized and therefore catabolized.…”

Section: High CM Diet Versus High Cm Diet With Phe Supplementationmentioning

confidence: 99%

See 1 more Smart Citation

Production responses of high producing Holstein cows to ruminally protected phenylalanine and tyrosine supplemented to diets containing high levels of canola meal

Swanepoel

Robinson

Erasmus

2018

Animal Feed Science and Technology

Self Cite

View full text Add to dashboard Cite

Phenylalanine (Phe) was first identified as a potentially limiting amino acid (AA) in lactating dairy cows in 1974. There is the possibility that conversion of Phe to tyrosine (Tyr) is not efficient enough to supply all Tyr requirements for milk production in high producing dairy cows, thereby suggesting that Tyr itself could become a functionally limiting AA when it, and/or Phe, is not supplied to the mammary gland in adequate quantities. Our objective was to determine if previous positive responses of lactating cows to Phe supplementation when fed a diet containing high levels of canola meal (CM) could be improved by supplying Tyr in place of some Phe. The experimental design was a 4×4 Latin square using 4 pens of ∼315 early lactation multiparous cows/pen with four 21 d periods. Diets were formulated to include a low CM treatment (LCM) containing CM at ~120 g CM/kg dry matter (DM) and a high CM treatment (HCM) with CM at ~170 g CM/kg DM. The other two treatments were the HCM diet, but with Phe (HCM+P) or Phe plus Tyr (HCM+PT) added in a ruminally protected (RP) form. The DM intake tended (P=0.10) to decline, but milk yield did not differ, between the LCM and HCM treatments, while milk fat, lactose and energy output was lower (P<0.02) with the HCM treatment, and body condition score (BCS) gain was enhanced (P<0.01). Adding Phe to the HCM diet had little impact on milk and component yields, but a positive BCS gain of 0.056 units/28 d decreased (P<0.01) to a loss of 0.025 units. Substitution of half the added Phe with Tyr lowered (P<0.05) milk and milk lactose yields while further lowering (P<0.01) the BCS loss to 0.080 units/28 d. While differences among diets in plasma AA concentrations were small, adding Phe to the HCM diet increased (P=0.05) plasma Phe and Ala (P=0.02), but plasma Phe only tended (P=0.09) to decline when Tyr partially replaced Phe to create the HCM+PT diet. Contrary to expectations based upon prior studies, increased CM inclusion from 120 to 170 g/kg DM only modestly decreased overall animal performance. While it is clear that supplementation of Phe, or Phe plus Tyr, to the HCM diet was not necessary, the 2 unexpected and substantive negative effects of Phe or Phe plus Tyr on overall animal performance suggests that the bioactivity of these AA is highly important, while highlighting the risks of supplementing AA that are not required.

show abstract

Section: Low CM Versus High Cm Diets Without Phe or Tyr Supplementationsupporting

confidence: 91%

Section: High CM Diet Versus High Cm Diet With Phe Supplementationmentioning

confidence: 99%

Production responses of high producing Holstein cows to ruminally protected phenylalanine and tyrosine supplemented to diets containing high levels of canola meal

Swanepoel

Robinson

Erasmus

2018

Animal Feed Science and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…A survey study examining comparisons between milk production, TMR ingredient profiles and plasma AA concentrations within 20 California (USA) dairy farms confirmed that plasma Phe concentrations are negatively correlated to the inclusion level of CM in the ration and that milk yield was negatively correlated with all plasma AA concentrations except Phe (Swanepoel et al, 2015b), supporting the hypothesis that Phe is important relative to milk production. Other studies feeding CM have shown a similar decline in plasma Phe compared to other protein sources (Christen et al, 2010), or a decrease in Phe proportions in metabolizable protein (MP) with higher dietary CM inclusions (Martineau et al, 2014), even though there were no changes in plasma Phe concentrations with different inclusion levels of CM (Mulrooney et al, 2009).…”

Section: Introductionmentioning

confidence: 83%

Impacts of adding ruminally protected phenylalanine to rations containing high levels of canola meal on performance of high producing Holstein cows

Swanepoel

Robinson

Erasmus

2016

Animal Feed Science and Technology

Self Cite

View full text Add to dashboard Cite

Highlights• Supplementation of Phe to early lactation cows receiving 170 g/kg of diet DM as CM.• Phe changed energy utilization, decreasing milk lactose while increasing BCS gain.• Phe resulted in an increase in whole tract aNDFom and ADF digestibility.• Phe support milk production after restoring mobilized peptides to muscle protein.• Phe regained animal performance lost when CM inclusion was increased. AbstractEven though studies supplementing Phe to dairy cattle are rare, it has been identified as limiting in corn silage based rations, after Lys and Met, as well as being important to the mammary gland for overall milk production. Since canola meal (CM) is low in Phe, plasma Phe concentrations decrease as more CM is included in dairy rations. A previous study fed 7.5 g/cow/day of intestinally absorbable Phe, but results suggested that it was insufficient to support increased milk production since it was primarily used to support increased body condition score (BCS;Swanepoel et al., 2015). Our objective was to determine if supplementing 15 g/cow/day of intestinally absorbable Phe in a ruminally protected (RP) form (HCMP) to a ration containing 170 g/kg CM (HCM) would support increased milk production after fulfilling its apparent 1 st priority of restoring previously mobilized peptides to muscle protein synthesis, thereby regaining animal performance possibly lost with higher dietary CM inclusion levels (i.e., 130 g/kg (LCM) to 165 g/kg (HCM)) based upon Swanepoel et al. (2015). Ruminally protected Met (2.0 g/cow/day intestinally absorbable) was added as part of the treatment ration to HCM treatments to avoid a possible Met limitation. The experimental design was a 3 x 3 Latin square using 3 pens of ~315 early lactation cows/pen with three 21 day periods. Dry matter (DM) intake was not affected (avg: 27.5 ± 0.5 kg/day) by feeding RP Phe and there was no impact of treatment on milk and component yields, except a reduced lactose content (P=0.02) with Phe addition. Even though plasma Phe levels only differed numerically between treatments, its supplementation resulted in energy being diverted towards BCS gain as in Swanepoel et al. (2015), but not at the expense of milk components, suggesting that higher Phe supplementation supplied enough Phe to replace mobilized muscle protein while maintaining milk production. The lack in change of plasma Phe concentrations could be due to extensive catabolization by the liver or hepatic conversion of Phe to Tyr, which is supported by the change in plasma Tyr concentrations.Interestingly, addition of Phe to the HCM ration increased whole tract neutral-and acid detergent fiber digestibility. Perhaps Phe released into the rumen when Phe was fed stimulated fibrolytic bacteria through a direct impact on microbes of free Phe, which has previously been shown to enhance growth and/or capabilities of cellulolytic bacteria. Total net energy output decreased with HCM feeding, but was restored to the level of the LCM ration for the HCMP treatment suggesting that further investigation to d...

show abstract

“…Proteolysis occurs in the form of nucleophile attacks on the peptide bonds, which may be endoproteolytic or exoproteolytic, by proteases, and the process normally occurs on the outside of cells that are intimately associated with the bacterial wall (e.g., adsorption of the proteins in cellulosomes) or occurs freely in other situations, with proteases being excreted into the ruminal medium. Nevertheless, bacteria exist which, depending on their species and strain, the trophic conditions of the moment, their molecular weight and the biochemical characteristics of the polypeptides to be digested, cause intracellular hydrolysis of the polypeptides (Asplund, 1994;Swanepoel et al, 2016). The protozoa typically swallow proteins, microparticles and microorganisms whole (e.g., bacteria, protozoa, and fungi), implying that, in most cases, protein digestion by these microorganisms is intracellular.…”

Section: Complexity Of Proteolysis In the Ruminal Ecosystemmentioning

confidence: 99%

“…From a methodological point of view, the importance of these phenomena for predicting protein degradability is that these acids and other metabolites can form substrates that promote microbial growth and reproduction, principally for many cellulolytic bacteria and other microorganisms that use these fatty acids as sources of energy and/or carbon chains. Normally, these isoacids, in conjunction with ammonium fixation, allow de novo synthesis of microbial amino acids (Ørskov, 1992;Van Soest, 1994;Chamberlain and Choung, 1995;Bull, 2001;Swanepoel et al, 2016), and the magnitude of the synthesis is mainly regulated by the activity of the enzymes glutamine synthetase, NADP-glutamate dehydrogenase and NAD-alanine dehydrogenase, whose K m values for ammonium fixation are 1.8, 1.8 to 3.1, and 70 mM of ammonium, respectively (Asplund, 1994). It should be noted that the degree of enzyme substrate affinity (K m ) will determine, in some way, the activity levels of these enzymes as a function of the intracellular nitrogen concentration of the microorganisms and the N content in the ruminal medium.…”

Section: Complexity Of Proteolysis In the Ruminal Ecosystemmentioning

confidence: 99%

Empirical Attributes and Limitations of Methodologies for Predicting the Degradability of Ruminal Protein

2016

View full text Add to dashboard Cite

present review is to analyze the methodologies that are commonly used to estimate protein degradability in the rumen, focusing on their attributes and limitations to offer suggestions for improving their use. This information is essential for selecting food types when formulating feed diets. A reliable prediction of the digestibility of ruminal proteins is basic information necessary for optimizing the use of nitrogenous sources because digestibility can translate, on the one hand, into higher yields of milk, milk protein, meat or wool and, on the other hand, into lower excretion of nitrogenous compounds into the environment; it also has an impact on animal health and welfare. Traditionally, the digestibility of feed proteins in the rumen has been predicted by in vivo, in situ and in vitro methods, but other techniques based on infrared spectroscopy have been developed, notably the NIRS and FTIR methods. All of these techniques present limitations, such as a disturbance factor or a source of error, that may result in inaccurate predictions. The in situ and in vitro methods, which use enzyme extracts of ruminal origin, and FTIR probably have the greatest advantages, but they need to be perfected through further research.

show abstract

Rumen microbial protein flow and plasma amino acid concentrations in early lactation multiparity Holstein cows fed commercial rations, and some relationships with dietary nutrients

Cited by 19 publications

References 63 publications

Production responses of high producing Holstein cows to ruminally protected phenylalanine and tyrosine supplemented to diets containing high levels of canola meal

Production responses of high producing Holstein cows to ruminally protected phenylalanine and tyrosine supplemented to diets containing high levels of canola meal

Impacts of adding ruminally protected phenylalanine to rations containing high levels of canola meal on performance of high producing Holstein cows

Empirical Attributes and Limitations of Methodologies for Predicting the Degradability of Ruminal Protein

Contact Info

Product

Resources

About