Quantitative animal nutrition and metabolism: a general review

Examples of increasing productivity of livestock enterprises over the last three to four decades, and the contribution to such advances, of scientific knowledge including that of the nutrition of farm livestock are referred to. Space limitations neccessitate restricting the review to consideration of ruminant livestock, with particular emphasis on ruminant digestive processes, on milk synthesis and on certain aspects of energy metabolism. Factors affecting the supply of amino acids to the host animal are referred to. The importance of synchronising N and energy supply to the rumen microorganisms to maximize microbial protein synthesis is emphasised and the need for knowledge of the extent to which particular feed proteins escape fermentation within the rumen. Concerning milk synthesis, the importance of an adequate supply of glucose or glucose precursors is mentioned as are the causes of the low milk fat syndrome. Limitations to existing knowledge of amino acid supply and milk protein synthesis are noted. Finally, aspects of ruminant energy metabolism studies are considered; particular stress is given to the importance of energy transactions in the intestinal wall as a major contributor to overall heat increment.

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Impact of post-ruminally infused macronutrients on bovine mammary gland expression of genes involved in fatty acid synthesis, energy metabolism, and protein synthesis measured in RNA isolated from milk fat

Journal of Animal Science and Biotechnology ◽

10.1186/s40104-020-00456-z ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Kelly Nichols ◽

André Bannink ◽

Jurgen van Baal ◽

Jan Dijkstra

Keyword(s):

Protein Synthesis ◽

Mammary Gland ◽

Fatty Acid ◽

Energy Metabolism ◽

Fatty Acid Synthesis ◽

Milk Fat ◽

Acid Synthesis ◽

Bovine Mammary Gland ◽

Expression Of Genes ◽

Mammary Gland Expression

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344 Supplementing different forms of l-methionine and acetate alters the expression patterns of messenger RNA, proteins, and metabolites related to milk protein synthesis and energy metabolism in bovine mammary cells

Journal of Animal Science ◽

10.2527/asasann.2017.344 ◽

2017 ◽

Vol 95 (suppl_4) ◽

pp. 170-170

Author(s):

J. R. V. Conejos ◽

S. W. Jeon ◽

M. H. Bae ◽

J. E. Lee ◽

B. S. Lee ◽

...

Keyword(s):

Protein Synthesis ◽

Energy Metabolism ◽

Messenger Rna ◽

Milk Protein ◽

Expression Patterns ◽

Mammary Cells

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Amino Acid Metabolism in Dairy Cows and their Regulation in Milk Synthesis

Current Drug Metabolism ◽

10.2174/1389200219666180611084014 ◽

2019 ◽

Vol 20 (1) ◽

pp. 36-45 ◽

Cited By ~ 2

Author(s):

Feiran Wang ◽

Haitao Shi ◽

Shuxiang Wang ◽

Yajing Wang ◽

Zhijun Cao ◽

...

Keyword(s):

Protein Synthesis ◽

Mammary Gland ◽

Dairy Cows ◽

Milk Fat ◽

Milk Protein ◽

Regulatory Element ◽

Mammalian Target Of Rapamycin ◽

Input Output ◽

Output Ratio ◽

Group 2

Background: Reducing dietary Crude Protein (CP) and supplementing with certain Amino Acids (AAs) has been known as a potential solution to improve Nitrogen (N) efficiency in dairy production. Thus understanding how AAs are utilized in various sites along the gut is critical. Objective: AA flow from the intestine to Portal-drained Viscera (PDV) and liver then to the mammary gland was elaborated in this article. Recoveries in individual AA in PDV and liver seem to share similar AA pattern with input: output ratio in mammary gland, which subdivides essential AA (EAA) into two groups, Lysine (Lys) and Branchedchain AA (BCAA) in group 1, input: output ratio > 1; Methionine (Met), Histidine (His), Phenylalanine (Phe) etc. in group 2, input: output ratio close to 1. AAs in the mammary gland are either utilized for milk protein synthesis or retained as body tissue, or catabolized. The fractional removal of AAs and the number and activity of AA transporters together contribute to the ability of AAs going through mammary cells. Mammalian Target of Rapamycin (mTOR) pathway is closely related to milk protein synthesis and provides alternatives for AA regulation of milk protein synthesis, which connects AA with lactose synthesis via α-lactalbumin (gene: LALBA) and links with milk fat synthesis via Sterol Regulatory Element-binding Transcription Protein 1 (SREBP1) and Peroxisome Proliferatoractivated Receptor (PPAR). Conclusion: Overall, AA flow across various tissues reveals AA metabolism and utilization in dairy cows on one hand. While the function of AA in the biosynthesis of milk protein, fat and lactose at both transcriptional and posttranscriptional level from another angle provides the possibility for us to regulate them for higher efficiency.

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Biosynthesis of milk fat, protein, and lactose: roles of transcriptional and posttranscriptional regulation

Physiological Genomics ◽

10.1152/physiolgenomics.00016.2015 ◽

2016 ◽

Vol 48 (4) ◽

pp. 231-256 ◽

Cited By ~ 68

Author(s):

Johan S. Osorio ◽

Jayant Lohakare ◽

Massimo Bionaz

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Milk Fat ◽

Posttranscriptional Regulation ◽

Milk Protein ◽

Mtor Pathway ◽

Amino Acid Transporters ◽

Fat Synthesis ◽

Milk Fat Synthesis

The demand for high-quality milk is increasing worldwide. The efficiency of milk synthesis can be improved by taking advantage of the accumulated knowledge of the transcriptional and posttranscriptional regulation of genes coding for proteins involved in the synthesis of fat, protein, and lactose in the mammary gland. Research in this area is relatively new, but data accumulated in the last 10 years provide a relatively clear picture. Milk fat synthesis appears to be regulated, at least in bovines, by an interactive network between SREBP1, PPARγ, and LXRα, with a potential role for other transcription factors, such as Spot14, ChREBP, and Sp1. Milk protein synthesis is highly regulated by insulin, amino acids, and amino acid transporters via transcriptional and posttranscriptional routes, with the insulin-mTOR pathway playing a central role. The transcriptional regulation of lactose synthesis is still poorly understood, but it is clear that glucose transporters play an important role. They can also cooperatively interact with amino acid transporters and the mTOR pathway. Recent data indicate the possibility of nutrigenomic interventions to increase milk fat synthesis by feeding long-chain fatty acids and milk protein synthesis by feeding amino acids. We propose a transcriptional network model to account for all available findings. This model encompasses a complex network of proteins that control milk synthesis with a cross talk between milk fat, protein, and lactose regulation, with mTOR functioning as a central hub.

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UFM1-Specific Ligase 1 Ligating Enzyme 1 Mediates Milk Protein and Fat Synthesis-Related Gene Expression via the JNK Signaling Pathway in Mouse Mammary Epithelial Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/4045674 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Meiqian Kuang ◽

Min Yang ◽

Lian Li ◽

Chengmin Li ◽

Genlin Wang

Keyword(s):

Protein Synthesis ◽

Epithelial Cells ◽

Milk Fat ◽

Milk Protein ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Fat Synthesis ◽

Jnk Activation

Ubiquitin-like modifier 1 ligating enzyme 1 (UFL1) has been characterized as a ubiquitin-like (Ubl) protein that affects a range of cellular processes across various pathways. In this study, mouse mammary epithelial cells (HC11 cell line) and UFL1 knockout (KO) mice were used to establish UFL1 knockdown models to explore the influence of UFL1 on milk protein and fat synthesis in the mouse mammary gland and the underlying mechanisms. This is the first study to show UFL1 localization in mouse mammary epithelial cells. UFL1 depletion by transfected UFL1 siRNA (siUFL1) caused aggravated apoptosis. In addition, UFL1 depletion suppressed milk protein synthesis-related protein level in vivo and in vitro. Conversely, ACACA and FASN expressions increased in UFL1-deficient mice. Moreover, UFL1 depletion increased triglyceride synthesis levels and inhibited the p-JNK expression. Importantly, the expression of proteins related to milk protein synthesis was decreased in JNK- and UFL1-deficient cells, whereas proteins related to milk fat synthesis showed the opposite trend, indicating that UFL1 affects milk protein and fat synthesis via the suppression of JNK activation. Overall, our findings indicate that UFL1 plays a key role in mammary milk and fat synthesis via JNK activation.

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Feed restriction in mid-lactation dairy cows. I: Effects on milk production and energy metabolism-related blood metabolites

10.1101/2020.06.12.140996 ◽

2020 ◽

Author(s):

I. Ansia ◽

Y. Ohta ◽

T. Fujieda ◽

J. K. Drackley

Keyword(s):

Energy Metabolism ◽

Milk Production ◽

Milk Fat ◽

Milk Protein ◽

Transition Period ◽

Nutrient Balance ◽

Daily Intake ◽

Feed Restriction ◽

Short Term ◽

Metabolic Adaptations

AbstractThe aim of the study was to describe the metabolic responses on energy metabolism to a period of negative nutrient balance induced by feed restriction (FR). Seven multiparous Holstein cows (93 ± 15 days in milk) were randomly assigned to 7 treatments in a 7 × 4 Youden square design. Daily intake was restricted to provide 60% of energy requirements during 5 d except for one treatment with ad libitum (AL) feeding. While 5 out of 7 experimental treatments involved abomasal supplementation of amino acids or glucose, in this article we evaluated only the effects of a negative nutrient balance by comparing both control treatments (AL and FR). Data of 2 cows within the AL group were removed due to sickness and therefore it had n = 2. Milk and energy corrected milk yield were reduced by FR. Yields of milk protein and lactose were lower during FR than during AL but the yield of milk fat only had a tendency (P > 0.06) to be lower with FR. Milk protein concentration was lower with FR than with AL but concentration of milk lactose and fat were not different between diets. The FR induced a decrease in plasma insulin and glucose concentrations, with quadratic decreasing trends both reaching nadirs on d 3. Simultaneously, non-esterified fatty acids (NEFA) concentration was greater and increased quadratically, peaking at d 3 during FR. There were no differences in daily β-hydroxybutyrate concentration, but it increased linearly until d 4 with FR. Comparison of the variation in concentration after feeding of insulin, NEFA and glucose could indicate a likely increased insulin sensitivity for peripheral NEFA uptake and a resistance for glucose uptake. This mechanism would contribute to decrease NEFA in circulation and sparing of glucose for lactose synthesis, respectively. Metabolic adaptations to a short-term reduction in dry matter intake include lipid mobilization, as well as modulation of peripheral tissue endocrine sensitivity in order to maintain yield of milk components production but prioritizing milk fat and lactose over milk protein.ImplicationsThe short-term feed restriction model described in this article can serve as an alternative to study metabolic adaptations during the transition period. The response of energy metabolism observed sets the baseline to measure the effect of nutrients supplementation and identify those candidates that will improve milk production and overall health after calving.

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Supplementing L-Isoleucine Increases Medium Protein and Alters the Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells

10.20944/preprints201906.0063.v1 ◽

2019 ◽

Author(s):

Jay Ronel Conejos ◽

Jae-Sung Lee ◽

Jin-Seung Park ◽

Jun-Ok Moon ◽

Hong-Gu Lee

Keyword(s):

Protein Synthesis ◽

Energy Metabolism ◽

Protein Kinase ◽

Milk Protein ◽

De Novo ◽

Wnt Signaling Pathway ◽

Pentose Phosphate ◽

Mitogen Activated Protein Kinase ◽

Cell Protein ◽

Optimal Time

The objective of this study was to determine the effects of supplementing L-isoleucine (L-Ile) on milk protein synthesis, using an immortalized bovine mammary epithelial (MAC-T) cell line. In this case, the cells were treated with 0, 0.3, 0.6, 0.9, 1.2 and 1.5 mM of supplemental Isoleucine (Ile), and the most efficient time for protein synthesis for each amino acid was determined by measuring the cell, medium and total protein at 0, 24, 48, 72 and 96 h. Confirmatory tests showed that 48h incubation time and 0.6 mM dosage of L-Ile are considered as the optimal time and dosage. The mechanism of milk protein synthesis was elucidated through proteomics analysis to clarify the metabolic pathway. When the L-Ile was supplemented, extracellular protein (medium protein) reached a peak at 48h, whereas in the case of the intracellular cell protein, it was shown to have reached to its peak at 24h in all L-Ile dosage treatments. In total, it is noted that there were 63 upregulated and 52 downregulated proteins. The results of the protein pathway analysis showed that the L-Ile group stimulated insulin/IGF pathway-mitogen activated protein kinase kinase/MAP kinase cascade, insulin/IGF pathway-protein kinase B signaling cascade, p53 pathway, de novo purine biosynthesis, Wnt signaling pathway, glycolysis, pentose phosphate pathway, and ATP synthesis which are pathways involved and related to protein and energy metabolism. Together, these results demonstrate that L-Ile supplementation was effective in stimulating β-casein synthesis by stimulating genes and pathways which are significantly related to protein and energy metabolism.

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Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22052751 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2751

Author(s):

Jay Ronel V. Conejos ◽

Jalil Ghassemi Nejad ◽

Jung-Eun Kim ◽

Jun-Ok Moon ◽

Jae-Sung Lee ◽

...

Keyword(s):

Protein Synthesis ◽

Energy Metabolism ◽

Milk Protein ◽

Mammalian Target Of Rapamycin ◽

Atp Synthesis ◽

Pentose Phosphate ◽

Mammary Epithelial ◽

Cell Protein ◽

Expression Of Genes ◽

Mrna Gene

The objective of this study was to investigate the effects of supplementing with L-tryptophan (L-Trp) on milk protein synthesis using an immortalized bovine mammary epithelial (MAC-T) cell line. Cells were treated with 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM of supplemental L-Trp, and the most efficient time for protein synthesis was determined by measuring cell, medium, and total protein at 0, 24, 48, 72, and 96 h. Time and dose tests showed that the 48 h incubation time and a 0.9 mM dose of L-Trp were the optimal values. The mechanism of milk protein synthesis was elucidated through proteomic analysis to identify the metabolic pathway involved. When L-Trp was supplemented, extracellular protein (medium protein) reached its peak at 48 h, whereas intracellular cell protein reached its peak at 96 h with all L-Trp doses. β-casein mRNA gene expression and genes related to milk protein synthesis, such as mammalian target of rapamycin (mTOR) and ribosomal protein 6 (RPS6) genes, were also stimulated (p < 0.05). Overall, there were 51 upregulated and 59 downregulated proteins, many of which are involved in protein synthesis. The results of protein pathway analysis showed that L-Trp stimulated glycolysis, the pentose phosphate pathway, and ATP synthesis, which are pathways involved in energy metabolism. Together, these results demonstrate that L-Trp supplementation, particularly at 0.9 mM, is an effective stimulus in β-casein synthesis by stimulating genes, proteins, and pathways related to protein and energy metabolism.

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