Plasma amino acid pattern during the first month of life in calves fed the first colostrum at 0-2 h or at 24-25 h after birth

Milk replacer feeding once or twice a day did not change the ruminal metabolomic profile and the microbial diversity of dairy calves from birth to weaning

In commercial dairy production systems, feeding calves once daily could be an alternative to reduce labor expenses. Several studies comparing once-a-day (OAD) versus twice-a-day (TAD) milk feeding systems have not evidenced differences in calf growth, rumen development, blood parameters or health scores, but effect on ruminal microbiota remains to be investigated. The objective of this study was to determine the effects of OAD or TAD on the establishment of the ruminal microbiota and its metabolic activity. Sixteen male calves (45.9 ± 5.7 kg at birth) were involved in the trial from birth to weaning (63 d). After the colostrum phase, 2 feeding programs based on a milk replacer were tested and calves were allocated to these programs on d 5. To study the establishment of the bacterial community, ruminal fluid was obtained from each calf 1 h after the morning meal at 7, 35, and 63 d of age. The ruminal metabolome was evaluated at a 7-d interval from d 1 to d 63. Ruminal microbiota and metabolite profiles were characterized by 16 S rRNA gene sequencing- and by 1H nuclear magnetic resonance spectroscopy, respectively. Our results showed that feeding milk replacer once or TAD did not change the ruminal microbiota and metabolites of dairy calves from birth to weaning. Microbial data showed that diversity and richness increased with age, suggesting a shift from a heterogeneous and less diverse community after birth (d 7) to a more diverse but homogeneous community at 35 and 63 d. These findings suggest that feeding milk OAD can be successfully applied to a calf feeding system without compromising microbial establishment and functions.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Determination of Free Amino Acids in Milk, Colostrum and Plasma of Swine via Liquid Chromatography with Fluorescence and UV Detection

Amino acids are ubiquitous components of mammalian milk and greatly contribute to its nutritional value. The compositional analysis of free amino acids is poorly reported in the literature even though their determination in the biological fluids of livestock animals is necessary to establish possible nutritional interventions. In the present study, the free amino acid profiles in mature swine milk, colostrum and plasma were assessed using a targeted metabolomics approach. In particular, 20 amino acids were identified and quantified via two alternative and complementary reversed-phase HPLC methods, involving two stationary phases based on core-shell technology, i.e., Kinetex C18 and Kinetex F5, and two detection systems, i.e., a diode array detector (DAD) and a fluorescence detector (FLD). The sample preparation involved a de-proteinization step, followed by pre-chromatographic derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). The two optimized methods were validated for specificity, linearity, sensitivity, matrix effect, accuracy and precision and the analytical performances were compared. The analytical methods proved to be suitable for free amino acid profiling in different matrices with high sensitivity and specificity. The correlations among amino acid levels in different biological fluids can be useful for the evaluation of physio-pathological status and to monitor the effects of therapeutic or nutritional interventions in humans and animals.

Label-free quantitative proteomics analysis reveals the fate of colostrum proteins in the intestine of neonatal calves

The contribution of intestinally absorbed colostral immunoglobulins to the transmission of passive immunity is widely reported in neonatal calves. However, changes in the colostral proteome in the gastrointestinal digesta remain unclear. Therefore, this study aimed to investigate changes in colostral proteome affected by gastrointestinal proteases in neonatal calves. Twenty-one neonatal Holstein calves were used in this study, including 18 colostrum-fed calves slaughtered at 8 (CI, n = 6), 24 (CII, n = 6), and 36 h (CIII, n = 6) postpartum and 3 milk-fed calves slaughtered 24 h postpartum (MI, n = 3). The ingested colostrum and milk samples were collected from the mid-jejunum segment, following the sacrifice. The undigested colostrum or milk along with their ingested colostrum or milk samples were investigated using a label-free proteomics approach. Hierarchical clustering and principal component analysis of the quantified proteins revealed that the ingested colostrum from the CII and CIII groups and the ingested mature milk from the MI group appeared to share similar patterns. Analysis of the intestinal digesta revealed a time-dependent decrease in caseins, lactoferrin, and osteopontin protein levels, and an increase in cationic trypsin, chymotrypsin, and carboxypeptidase. Several protease inhibitors, such as α-1-antiproteinase, α-2-antiplasmin, and early lactation protein, were identified in the colostrum and intestinal digesta. In addition, we detected identical levels in the intestinal digesta and colostrum for albumin, α-1-acid glycoprotein, and plasminogen. Pathway analysis indicated that proteins increased in the intestinal digesta belonged to the following categories: biosynthesis of antibiotics, carbon metabolism, and biosynthesis of amino acids. These results indicated that selected colostral proteins were digested by gastrointestinal proteases, contributing to their intestinal absorption in calves. These findings provide new insights into the fate of the colostral proteome in the gastrointestinal tract and may aid in the identification of factors contributing to health management in neonatal calves.

Changes in whey proteome with lactation stage and parity in dairy cows using a label-free proteomics approach

Milk yield and several components of milk that are affected by physiological factors have been widely investigated. However, the effects of lactation stage and parity on bovine milk whey proteins have not been well elucidated. To aid in unraveling the proteome profile and exploring the protein biosynthesis of mammary glands, a label-free proteomic approach was used to characterize whey proteomes depending on the lactation stage and parity of dairy cows. The results of this study show that the abundances of several proteins, such as early lactation protein, syntenin, and heparanase, were associated with specific stages of the lactation cycle; this was evidenced by a principal component analysis. In addition, several proteins, such as hemoglobin subunits beta and alpha, β-lactoglobulin, CD320, and apolipoprotein E, corresponded to the parity of the dairy cows and were herein considered as useful biomarkers to distinguish different parities. Most of the differentially expressed proteins from specific lactation stages and parity milk groups were annotated in the response to stimulus and protein metabolic processes. The findings reveal that developmental changes in whey proteomes correspond to lactation stages and parities, which in turn provides new insight into the underlying implications of the production of specific proteins to meet the health benefits of offspring and host, and allow us to explore the mechanisms of protein biosynthesis in mammary glands associated with physiological changes in dairy cows.

Exploration of the Relationship between Intestinal Colostrum or Milk, and Serum Metabolites in Neonatal Calves by Metabolomics Analysis

In contrast to colostral immunoglobulins, changes in metabolite composition of ingested colostrum in the gut have received little attention. Here, we characterized the metabolite profiles of colostrum and milk, ingested colostrum and milk, and serum of neonatal calves by liquid chromatography tandem-mass spectrometry and gas chromatography-mass spectrometry metabolomics approaches. Colostrum and milk underwent similar changes in metabolite profiles in the gut after being ingested. These changes were characterized by increases in methionine, glutamate, thymine, and phosphorylcholine. After ingestion, colostrum concentrations of several metabolites, such as γ-aminobutyric acid, glutamate, cinnamic acid, and thymine increased, whereas concentrations of d-ribose, and arginine decreased. These increases and decreases occurred in a time-dependent manner and were associated with alanine, aspartate, glutamate, and pyrimidine metabolism, and valine, leucine, and isoleucine biosynthesis, respectively. Meanwhile, similar changes in serum metabolites were also observed in neonatal calves fed colostrum, which implies that colostrum metabolites are transported across the small intestine and into the bloodstream. In addition, several metabolites of ingested milk were detected in the gut, and were also transferred to the bloodstream. These metabolites were related to phenylalanine, tyrosine, tryptophan, valine, leucine, and isoleucine biosynthesis, the citrate cycle, and histidine metabolism. These findings reveal that the serum metabolome of neonatal calves' changes as a result of ingesting colostrum, which can provide health-related benefits in early life.

Mammalian target of rapamycin signaling and ubiquitin proteasome-related gene expression in 3 different skeletal muscles of colostrum- versus formula-fed calves

The rates of protein turnover are higher during the neonatal period than at any other time in postnatal life. The mammalian target of rapamycin (mTOR) and the ubiquitin-proteasome system are key pathways regulating cellular protein turnover. The objectives of this study were (1) to elucidate the effect of feeding colostrum versus milk-based formula on the mRNA abundance of key components of the mTOR pathway and of the ubiquitin-proteasome system in skeletal muscle of neonatal calves and (2) to compare different muscles. German Holstein calves were fed either colostrum (COL; n = 7) or milk-based formula (FOR; n = 7) up to 4 d of life. The nutrient content in formula and colostrum was similar, but formula had lower concentrations of free branched-chain AA (BCAA) and free total AA, insulin, and insulin-like growth factor (IGF)-I than colostrum. Blood samples were taken from d 1 to 4 before morning feeding and before and 2 h after the last feeding on d 4. Muscle samples from M. longissimus dorsi (MLD), M. semitendinosus (MST), and M. masseter (MM) were collected after slaughter on d 4 at 2 h after feeding. The preprandial concentrations of free total AA and BCAA, insulin, and IGF-I in plasma changed over time but did not differ between groups. Plasma free total AA and BCAA concentrations decreased in COL, whereas they increased in FOR after feeding, resulting in higher postprandial plasma total AA and BCAA concentrations in FOR than in COL. Plasma insulin concentrations increased after feeding in both groups but were higher in COL than in FOR. Plasma IGF-I concentrations decreased in COL, whereas they remained unchanged in FOR after feeding. The mRNA abundance of mTOR and ribosomal protein S6 kinase 1 (S6K1) in 3 different skeletal muscles was greater in COL than in FOR, whereas that of eukaryotic translation initiation factor 4E binding protein 1 (4EBP1) was unaffected by diet. The mRNA abundance of ubiquitin activating enzyme (UBA1) and ubiquitin conjugating enzyme 1 (UBE2G1) enzymes was not affected by diet, whereas that of ubiquitin conjugating enzyme 2 (UBE2G2) was greater (MLD) or tended to be greater (MM) in COL than in FOR. The mRNA abundance of atrogin-1 in MLD and MST was lower in COL than in FOR, whereas that of muscle ring finger protein-1 (MuRF1) was greater (MST) or tended to be greater (MLD). The abundance of MuRF1 mRNA was highest in MST, followed by MLD, and was lowest in MM. The results indicate that colostrum feeding may stimulate protein turnover that may result in a high rate of protein deposition in a muscle type-specific manner. Such effects seem to be mediated by the postprandial increase in plasma insulin.

Chemical composition of yak colostrum and transient milk

The objective of this study was to assess the changes in the chemical composition of yak colostrum and transient milk. Samples were collected from 12 yaks on days 1, 2, 3, 4, 5, 6 and 7 post-partum (PP). The gross composition, nitrogen fraction distribution, amino acid (AA) profile and fatty acid (FA) profile were analysed. All the components decreased rapidly during the first 3 days except lactose which increased. The ratio of whey protein to casein protein decreased from 46:54 to 17:83 during the first 7 days PP. The content of all the AAs decreased, while the percentages of eight essential AAs in protein of samples increased during the study period. Monounsaturated FAs and polyunsaturated FAs decreased in the first 7 days PP, whereas saturated FAs increased. In conclusion, the changes in chemical composition were remarkable during the first 3 days. The slight variations, happened during the transient period, are not negligible, which also should be taken into account in the development of yak colostrum supplements.

Insulin-like growth factors (IGFs), IGF binding proteins, and other endocrine factors in milk: role in the newborn

The role of colostrum and milk in the neonate has been chiefly recognized as a comprehensive nutrient foodstuff. In addition, the provision of colostrum-the first milk-for early immune capacity has been well documented for several species. Colostrum is additionally a rich and concentrated source of various factors that demonstrate biological activity in vitro. Three hypotheses have been proposed for the phenotypic function of these secreted bioactive components: (1) only mammary disposal, (2) mammary cell regulation, and (3) neonatal function [gastrointestinal tract (GIT) or systemic]. Traditionally, it was assumed that the development of the GIT is preprogrammed and not influenced by events occurring in the intestinal lumen. However, a large volume of research has demonstrated that colostrum (or milk-borne) bioactive components can basically contribute to the regulation of GIT growth and differentiation, while their role in postnatal development at physiological concentrations has remained elusive. Much of our current understanding is derived from cell culture and laboratory animals, but experimentation with agriculturally important species is taking place. This chapter provides an overview of work conducted primarily in neonatal calves and secondarily in other species on the effects on neonates of selected peptide endocrine factors (hormones, growth factors, in part cytokines) in colostrum. The primary focus will be on insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) and other bioactive peptides, but new interest and concern about steroids (especially estrogens) in milk are considered as well.

Nutritional physiology of neonatal calves*

The gastrointestinal tract of neonatal calves is relatively mature but still requires morphological and functional changes. The intake of colostrum with its nutrient and non-nutrient components exerts marked effects on gastrointestinal development and function. Colostrum intake provides immunoprotection (passive immunity by immunoglobulins) and is essential for survival of neonates of most species. Furthermore, there are important transient as well as long-lasting systemic effects on the nutritional status, on metabolism, and on various endocrine systems due to intake of nutrient and non-nutrient colostral components that contribute to survival in the stressful postnatal period. Colostrum is much more than just a supplier of immunoglobulins.

Delayed feeding of first colostrum: are there prolonged effects on haematological, metabolic and endocrine parameters and on growth performance in calves?

To test the hypothesis that delaying first colostrum feeding of calves after birth exerts long-lasting effects on haematological, metabolic and endocrine traits and on growth performance, neonatal calves were fed first colostrum at 0-2 and 24-25 h after birth. Delayed feeding of first colostrum for 24-25 h after birth caused reduced plasma levels of total protein and globulin for up to 30 days and of insulin-like growth factor-I for up to 7 days, whereas concentrations of nonesterified fatty acids were elevated during the first day of life. There were no significant effects of delaying feeding for 24-25 h on leucocyte and erythrocyte number, packed cell volume and on haemoglobin levels and on plasma concentrations of albumin, urea, glucose, triglycerides, phospholipids, cholesterol, insulin, growth hormone, 3.5.3'-triiodothyronine and thyroxine and on growth performance. Thus, calves fed first colostrum with a delay of 24-25 h after birth were able to compensate rapidly for nutritional deficiencies on day 1 of life, i.e. there was no evidence for permanent imprinting of haematological, metabolic and of endocrine traits by starvation on the first day of life.

Activities of gamma-glutamyltransferase, alkaline phosphatase and aspartate-aminotransferase in colostrum, milk and blood plasma of calves fed first colostrum at 0-2, 6-7, 12-13 and 24-25 h after birth

Enzyme activities of gamma-glutamyltransferase (gamma-GT), alkaline phosphatase (AP) and aspartate-aminotransferase (AST) were measured from birth to the age of 28 days in calves which were fed colostrum at 0-2, 6-7, 12-13, or 24-25 h after birth. Enzyme activities were also measured in colostrum (first to fifth milking) and in mature milk. Activities were highest in the first colostrum milking and decreased to the lowest activities in mature milk. Plasma gamma-GT activity transiently increased after first colostrum intake and was greater in calves fed first colostrum within less than 6-7 h than in those fed first colostrum later than 12 h after birth. Activity of gamma-GT reflected the absorption of colostral gamma-GT, which decreased with time after birth. The AP activity transiently increased after colostrum intake and was higher in calves fed colostrum within the first 12 h of life than in those fed later after birth. The transient rise of plasma AP activity also indicated absorption of colostral AP, although endogenous sources of AP could not be excluded. The activity of AST also transiently increased after colostrum intake but there was no association with time of first colostrum feeding, indicating that the rise of plasma AST activity was the consequence of enhanced endogenous production and was independent of colostrum intake. In conclusion, there are different causes leading to postnatal changes in enzyme activities.