Effects of dietary leucine and phenylalanine on pancreas development, enzyme activity, and relative gene expression in milk-fed Holstein dairy calves

Cao, Yangchun; Yang, Xiaojun; Guo, Long; Chen, Zheng; Wang, D.D.; Cai, Chuanjiang; Liu, S.M.; Yao, Junhu

doi:10.3168/jds.2017-13987

Cited by 23 publications

(27 citation statements)

References 44 publications

(77 reference statements)

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“…They reported that leucine infused at 10 g/day increased pancreatic α-amylase secretion. However, supplementing additional phenylalanine and leucine in milk-fed calves did not increase pancreatic α-amylase (Cao et al, 2018).…”

Section: Small Intestinal Starch Digestionmentioning

confidence: 80%

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Harmon

Swanson

2020

Animal

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Pregastric fermentation along with production practices that are dependent on high-energy diets means ruminants rely heavily on starch and protein assimilation for a substantial portion of their nutrient needs. While the majority of dietary starch may be fermented in the rumen, significant portions can flow to the small intestine. The initial phase of small intestinal digestion requires pancreatic α-amylase. Numerous nutritional factors have been shown to influence pancreatic α-amylase secretion with starch producing negative effects and casein, certain amino acids and dietary energy having positive effects. To date, manipulation of α-amylase secretion has not resulted in substantial changes in digestibility. The second phase of digestion involves the actions of the brush border enzymes sucrase-isomaltase and maltase-glucoamylase. Genetically, ruminants appear to possess these enzymes; however, the absence of measurable sucrase activity and limited adaptation with changes in diet suggests a reduced capacity for this phase of digestion. The final phase of carbohydrate assimilation is glucose transport. Ruminants possess Na+-dependent glucose transport that has been shown to be inducible. Because of the nature of pregastric fermentation, ruminants see a near constant flow of microbial protein to the small intestine. This results in a nutrient supply, which places a high priority on protein digestion and utilization. Comparatively, little research has been conducted describing protein assimilation. Enzymes and processes appear consistent with non-ruminants and are likely not limiting for efficient digestion of most feedstuffs. The mechanisms regulating the nutritional modulation of digestive function in the small intestine are complex and coordinated via the substrate, neural and hormonal effects in the small intestine, pancreas, peripheral tissues and the pituitary—hypothalamic axis. More research is needed in ruminants to help unravel the complexities by which small intestinal digestion is regulated with the aim of developing approaches to enhance and improve the efficiency of small intestinal digestion.

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Section: Small Intestinal Starch Digestionmentioning

confidence: 80%

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Harmon

Swanson

2020

Animal

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“…The dose of leucine was approximately 42% of leucine in the milk, and 0.98 g/L alanine was added into milk for control group to make the milk isonitrogenous between two groups. The dose of leucine in this study was based on the result of Cao et al ().…”

Section: Methodsmentioning

confidence: 99%

“…The overview of the experimental protocol was shown in Figure and detailed by Cao et al (). Briefly, within one hour after birth, all calves were fed 4.0 L colostrum and then housed in individual calf hutch.…”

Section: Methodsmentioning

confidence: 99%

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Leucine‐induced promotion of post‐absorptive EAA utilization and hepatic gluconeogenesis contributes to protein synthesis in skeletal muscle of dairy calves

Chen

Yao

Guo

et al. 2019

Animal Physiology Nutrition

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The high rate of protein synthesis in skeletal muscle of dairy calves can benefit their first lactation even lifetime milk yield. Since the rate of protein synthesis is relatively low in the post‐absorptive state, the aim of this research was to determine whether leucine supplementation could increase the post‐absorptive essential amino acid (EAA) utilization and protein synthesis in the skeletal muscle. Ten male neonatal dairy calves (38 ± 3 kg) were randomly assigned to either the control (CON, no leucine supplementation, n = 5) or supplementation with 1.435 g leucine/L milk (LEU, n = 5). Results showed that leucine significantly increased the length and protein concentration in longissimus dorsi (LD) muscle, whereas it decreased creatinine concentration and glutamic‐oxalacetic transaminase (GOT) activity. Compared to the control group, leucine supplementation also reduced the glutamic‐pyruvic transaminase (GPT) activity. Supplementation of leucine improved the phosphorylation of mammalian target of rapamycin (mTOR), eukaryotic initiation factor 4E‐binding protein 1 (4EBP1) and substrates ribosomal protein S6 kinase 1 (p70S6K). Supplementation of leucine resulted in increased concentrations of glucose, methionine, threonine, histidine and EAAs and decreased concentration of arginine in serum. Liver glucose concentration was higher and pyranic acid was lower in LEU compared to CON. In conclusion, leucine supplementation can promote post‐absorptive EAA utilization and hepatic gluconeogenesis, which contributes to protein synthesis in skeletal muscle of dairy calves.

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“… 44 Other studies also have shown the role of leucine in the exocrine pancreas of rats, 45 pigs, 46 and ruminants. 47 …”

mentioning

confidence: 99%

Dietary Protein and Amino Acid Deficiency Inhibit Pancreatic Digestive Enzyme mRNA Translation by Multiple Mechanisms

Sans

Crozier

Vogel

et al. 2021

Cellular and Molecular Gastroenterology and Hepatology

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Background & Aims Chronic amino acid (AA) deficiency, as in kwashiorkor, reduces the size of the pancreas through an effect on mammalian target of rapamycin complex 1 (mTORC1). Because of the physiological importance of AAs and their role as a substrate, a stimulant of mTORC1, and protein synthesis, we studied the effect of acute protein and AA deficiency on the response to feeding. Methods ICR/CD-1 mice were fasted overnight and refed for 2 hours with 4 different isocaloric diets: control (20% Prot); Protein-free (0% Prot); control (AA-based diet), and a leucine-free (No Leu). Protein synthesis, polysomal profiling, and the activation of several protein translation factors were analyzed in pancreas samples. Results All diets stimulated the Protein Kinase-B (Akt)/mTORC1 pathway, increasing the phosphorylation of the kinase Akt, the ribosomal protein S6 (S6) and the formation of the eukaryotic initiation factor 4F (eIF4F) complex. Total protein synthesis and polysome formation were inhibited in the 0% Prot and No Leu groups to a similar extent, compared with the 20% Prot group. The 0% Prot diet partially reduced the Akt/mTORC1 pathway and the activity of the guanine nucleotide exchange factor eIF2B, without affecting eIF2α phosphorylation. The No Leu diet increased the phosphorylation of eIF2α and general control nonderepressible 2, and also inhibited eIF2B activity, without affecting mTORC1. Essential and nonessential AA levels in plasma and pancreas indicated a complex regulation of their cellular transport mechanisms and their specific effect on the synthesis of digestive enzymes. Conclusions These studies show that dietary AAs are important regulators of postprandial digestive enzyme synthesis, and their deficiency could induce pancreatic insufficiency and malnutrition.

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Effects of dietary leucine and phenylalanine on pancreas development, enzyme activity, and relative gene expression in milk-fed Holstein dairy calves

Cited by 23 publications

References 44 publications

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Leucine‐induced promotion of post‐absorptive EAA utilization and hepatic gluconeogenesis contributes to protein synthesis in skeletal muscle of dairy calves

Dietary Protein and Amino Acid Deficiency Inhibit Pancreatic Digestive Enzyme mRNA Translation by Multiple Mechanisms

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