Intramammary administration of lipopolysaccharides at parturition does not affect the transfer of passive immunity in goat kids

This study evaluated the effect of feeding colostrum obtained from an intramammary administration (IA) of LPS from Escherichia coli (O55:B5) to dairy goats at parturition, on goat kids performance, biochemical parameters (i.e., calcium, LDH, glucose, total proteins, albumin, and urea) and immune status (i.e., IgG and IgM) during the first month of life. At birth, goat kids were weighted (d 0) and immediately allocated into either the LPS group (n = 15) or the CON group (n = 21) based on the experimental group of the dam. At parturition, 20 multiparous dairy goats were allocated in one of the 2 experimental groups (LPS vs. CON). The LPS group received an IA of saline solution (2 mL) containing 50 µg of LPS in each half udder whereas goats in the CON group received an IA of saline solution (2 mL) without LPS. Goat kids were bottle-fed dam colostrum equivalent to 10% of the birth BW divided in 2 meals (i.e., at 3 and 12 h relative to birth), and then fed twice daily with milk replacer ad libitum. Individual milk intake (MI) and BW were recorded on d 7, 15, 21 and 30 of life. Blood samples were collected on d 0, 1, 2, 4, 7, 15, 21 and 30 after birth. Data was analyzed using the MIXED procedure of SAS (9.4). The model included IA, time (T) and the interaction (IA x T) as fixed effects and sex and litter size as random effects. Both groups showed similar MI, except on d 7 relative to birth as the LPS group showed higher MI than the CON group (910.5 ± 69.77 and 683.9 ± 59.64 mL, respectively). No differences in BW or rectal temperature were observed between groups, neither in plasma IgG nor IgM concentrations. Despite the IA did not affect calcium, glucose, LDH, total protein, and albumin concentrations an interaction between the IA and T was observed for urea concentration, showing the LPS group higher urea concentrations than the CON group on d 0 (20.1 ± 1.34 and 20.0 ± 1.25 mg/dL, respectively). In conclusion, feeding colostrum from goats that received an IA of LPS at parturition does not affect goat kid performance, plasma immunoglobulin concentrations and serum metabolites during the first month of life.

Post translational modifications of milk proteins in geographically diverse goat breeds

Goat milk is a source of nutrition in difficult areas and has lesser allerginicity than cow milk. It is leading in the area for nutraceutical formulation and drug development using goat mammary gland as a bioreactor. Post translational modifications of a protein regulate protein function, biological activity, stabilization and interactions. The protein variants of goat milk from 10 breeds were studied for the post translational modifications by combining highly sensitive 2DE and Q-Exactive LC-MS/MS. Here we observed high levels of post translational modifications in 201 peptides of 120 goat milk proteins. The phosphosites observed for CSN2, CSN1S1, CSN1S2, CSN3 were 11P, 13P, 17P and 6P, respectively in 105 casein phosphopeptides. Whey proteins BLG and LALBA showed 19 and 4 phosphosites respectively. Post translational modification was observed in 45 low abundant non-casein milk proteins mainly associated with signal transduction, immune system, developmental biology and metabolism pathways. P_asp is reported for the first time in 47 sites. The rare conserved peptide sequence of (SSSEE) was observed in αS1 and αS2 casein. The functional roles of identified phosphopeptides included anti-microbial, DPP-IV inhibitory, anti-inflammatory and ACE inhibitory. This is first report from tropics, investigating post translational modifications in casein and non-casein goat milk proteins and studies their interactions.

The Impact of Mastitis on the Biochemical Parameters, Oxidative and Nitrosative Stress Markers in Goat's Milk: A Review

Goat mastitis has become one of the most frequently diagnosed conditions in goat farms, with significant economic impact on the dairy industry. Inflammation of the mammary gland poses serious consequences on milk composition, with changes regarding biochemical parameters and oxidative stress markers. The aim of this paper is to present the most recent knowledge on the main biochemical changes that occur in the mastitic milk, as well as the overall effect of the oxidative and nitrosative stress on milk components, focusing on both enzymatic and nonenzymatic antioxidant markers. Mastitis in goats is responsible for a decrease in milk production, change in protein content with pronounced casein hydrolysis, and reduction in lactose concentration and milk fat. Milk enzymatic activity also undergoes changes, regarding indigenous enzymes and those involved in milk synthesis. Furthermore, during mastitis, both the electrical conductivity and the milk somatic cell count are increased. Intramammary infections are associated with a reduced milk antioxidant capacity and changes in catalase, lactoperoxidase, glutathione peroxidase or superoxide dismutase activity, as well as reduced antioxidant vitamin content. Mastitis is also correlated with an increase in the concentration of nitric oxide, nitrite, nitrate and other oxidation compounds, leading to the occurrence of nitrosative stress.

Novel Biomarkers of Mastitis in Goat Milk Revealed by MALDI-TOF-MS-Based Peptide Profiling

Mastitis is the most common infection of dairy goats impairing milk production and quality, which is usually recognized by mammary gland visual inspection and palpation. Subclinical forms of the disease are also widely represented, which lack the typical signs of the clinical ones but are still associated with reduced production and safety for human consumption of milk, generally presenting a high bacterial count. In order to obtain novel analytical tools for rapid and non-invasive diagnosis of mastitis in goats, we analyzed milk samples from healthy, subclinical and clinical mastitic animals with a MALDI-TOF-MS-based peptidomic platform, generating disease group-specific spectral profiles whose signal intensity and mass values were analyzed by statistics. Peculiar spectral signatures of mastitis with respect to the control were identified, while no significant spectral differences were observed between clinical and subclinical milk samples. Discriminant signals were assigned to specific peptides through nanoLC-ESI-Q-Orbitrap-MS/MS experiments. Some of these molecules were predicted to have an antimicrobial activity based on their strong similarity with homolog bioactive compounds from other mammals. Through the definition of a panel of peptide biomarkers, this study provides a very rapid and low-cost method to routinely detect mastitic milk samples even though no evident clinical signs in the mammary gland are observed.

Functional milk proteome analysis of genetically diverse goats from different agro climatic regions

Goat milk, a choice of substitution to mother's milk for its composition, fulfils nutritional requirement of infants, pregnant mothers and older people. The present study was carried out to unravel the milk proteome profiles from geographically and genetically diverse goat breeds by gel based 2DE and nLC-MS/MS. A total of 1307 functional proteins comprising casein and other low abundance proteins were identified. Gene annotations revealed that the majority of the proteins were involved in binding function, catalytic activity and structural molecules and localised in nucleus and membrane. The distinguished proteins were involved in 144 KEGG pathways in information processing, metabolism, cellular process, organismal systems and diseases. The large number of proteins and peptides including bioactive peptides were reported from goat milk from diverse agro-climatic regions of India indicating their significant potential for human health applications. SIGNIFICANCE: Goat milk in India is used in various Ayurvedic formulations to treat a number of ailments and allergies as well as for nutraceutical formulations. The study identifies milk protein variants both at protein and DNA level and subsequent identification of proteins by 2DE and nLC-MS/MS resulting in a proteome comprising of 1307 proteins. The specific proteins and peptides having significant role in immune regulation, disease pathways, cellular growth and metabolism have been identified. The results contribute to goat milk protein and peptide database which is very limited. We identified proteins for specific functional categories and associated them with different pathways for studying functional diversity of goat milk proteins. The proteins and peptides identified can be used for multiple human health application.

Impact of Staphylococcus aureus infection on the late lactation goat milk proteome: New perspectives for monitoring and understanding mastitis in dairy goats

The milk somatic cell count (SCC) is a standard parameter for monitoring intramammary infections (IMI) in dairy ruminants. In goats, however, the physiological increase in SCC occurring in late lactation heavily compromises its reliability. To identify and understand milk protein changes specifically related to IMI, we carried out a shotgun proteomics study comparing high SCC late lactation milk from goats with subclinical Staphylococcus aureus IMI and from healthy goats to low SCC mid-lactation milk from healthy goats. As a result, we detected 52 and 19 differential proteins (DPs) in S. aureus-infected and uninfected late lactation milk, respectively. Unexpectedly, one of the proteins higher in uninfected milk was serum amyloid A. On the other hand, 38 DPs were increased only in S. aureus-infected milk and included haptoglobin and numerous cytoskeletal proteins. Based on STRING analysis, the DPs unique to S. aureus infected milk were mainly involved in defense response, cytoskeleton organization, cell-to-cell, and cell-to-matrix interactions. Being tightly and specifically related to infectious/inflammatory processes, these proteins may hold promise as more reliable markers of IMI than SCC in late lactation goats. SIGNIFICANCE: The biological relevance of our results lies in the increased understanding of the changes specifically related to bacterial infection of the goat udder in late lactation. The DPs present only in S. aureus infected milk may find application as markers for improving the specificity of subclinical mastitis monitoring and detection in dairy goats in late lactation, when other widespread tools such as the SCC lose diagnostic value.

Short communication: Characterization of the milk protein expression profiles in dairy buffaloes with and without subclinical mastitis

The aim of this study was to characterize the proteins present in milk whey from buffaloes with and without subclinical mastitis using a proteomic approach to identify differentially expressed proteins as potential biomarkers for this disease. Whey from Murrah buffaloes with subclinical mastitis was compared with whey from healthy animals using liquid chromatography-tandem mass spectrometry. The annotated protein databases for Bubalus bubalis and Bos taurus were used in the analysis, and the gene annotations from the buffalo and bovine reference assemblies were also used. After integrating gene annotations from both buffaloes and bovines, a total of 1,033 proteins were identified, of which 156 were differentially expressed. Eighteen biological processes were annotated with Gene Ontology. Cathelicidin-3 was identified as a potential biomarker for subclinical mastitis. These results are important to the characterization of mastitis in the buffalo mammary gland and may aid in the development of tools for early diagnosis.

Relationship of Late Lactation Milk Somatic Cell Count and Cathelicidin with Intramammary Infection in Small Ruminants

Late lactation is a critical moment for making mastitis management decisions, but in small ruminants the reliability of diagnostic tests is typically lower at this stage. We evaluated somatic cell counts (SCC) and cathelicidins (CATH) in late lactation sheep and goat milk for their relationship with intramammary infections (IMI), as diagnosed by bacteriological culture (BC). A total of 315 sheep and 223 goat half-udder milk samples collected in the last month of lactation were included in the study. IMI prevalence was 10.79% and 15.25%, respectively, and non-aureus staphylococci were the most common finding. Taking BC as a reference, the diagnostic performance of SCC and CATH was quite different in the two species. In sheep, receiver operating characteristic (ROC) analysis produced a higher area under the curve (AUC) value for CATH than SCC (0.9041 versus 0.8829, respectively). Accordingly, CATH demonstrated a higher specificity than SCC (82.92% versus 73.67%, respectively) at comparable sensitivity (91.18%). Therefore, CATH showed a markedly superior diagnostic performance than SCC in late lactation sheep milk. In goats, AUC was <0.67 for both parameters, and CATH was less specific than SCC (61.90% versus 65.08%) at comparable sensitivity (64.71%). Therefore, both CATH and SCC performed poorly in late lactation goats. In conclusion, sheep can be screened for mastitis at the end of lactation, while goats should preferably be tested at peak lactation. In late lactation sheep, CATH should be preferred over SCC for its higher specificity, but careful cost/benefit evaluations will have to be made.

Proteomic analysis of goat milk kefir: Profiling the fermentation-time dependent protein digestion and identification of potential peptides with biological activity

Kefir is a fermented dairy product, associated to health benefits because of being a probiotic and due to the presence of molecules with biological activity. In this work, we have profiled the peptide composition of goat milk kefir at three different fermentation times using a peptidomics approach, in order to study changes in peptide concentrations and patterns of protein digestion throughout the fermentation time. We identified 2328 unique peptides corresponding to 22 protein annotations, with a maximum of peptides found after 24 h fermentation. We established different digestion patterns according to the nature of the proteins, and quantified the changes in the peptides appearing in all the fermentation times. We also identified 11 peptides that matched exactly to sequences with biological activity in databases, almost all of them belonging to caseins. This is the most comprehensive proteomic analysis of goat milk kefir to date.

Anti-inflammatory mechanism of ginsenoside Rg1: Proteomic analysis of milk from goats with mastitis induced with lipopolysaccharide

Previous investigation showed that intravenous injection of ginsenoside Rg1 had a therapeutic effect on Escherichia coli lipopolysaccharide-induced mastitis in lactating goats and it protected animals from lipopolysaccharide challenge via toll-like receptor 4 signaling pathway. The present study was to use proteomic approach to explore the anti-inflammatory mechanisms of Rg1. Nine dairy goats were randomly divided into three groups with 3 animals in each: groups 1 and 2 received intra-mammary infusion of lipopolysaccharide and then intravenously injected with saline or Rg1 solution; animals in group 3 were first intramammarily and then intravenously administered saline solution, and served as a control group. Milk whey at 6 h post lipopolysaccharide challenge was prepared for tandem mass tags based quantitative proteomic analysis. The results showed that 791 proteins were totally identified from the whey. Of them, 98 proteins between groups 1 (lipopolysaccharide + Saline) and 3 (Saline + Saline), and 34 proteins between groups 2 (lipopolysaccharide + Rg1) and 1 were significantly different. Group 1 than group 3 had significantly more inflammatory factors such as interleukin 6, acute phase proteins, blood coagulation factors, complement proteins, and oxidative stress markers while these factors were reduced in group 2 treated with Rg1. In addition, proteins in group 2 associated with peroxisome-proliferator-activated receptor γ activation and recovery of milk fat and production were upregulated compared to group 1. Therefore, Rg1 may exert its anti-inflammatory effect on lipopolysaccharide-induced mastitis in goats via modulating expression of proteins relating to peroxisome-proliferator-activated receptor γ and toll-like receptor 4 signaling pathway.

Small ruminant lentivirus infection influences expression of acute phase proteins and cathelicidin genes in milk somatic cells and peripheral blood leukocytes of dairy goats

The aim of the study was to analyze acute phase protein and cathelicidin gene responses to small ruminant lentivirus (SRLV) infection in goats. In uninfected goats, we found higher Cp and lower Fbγ mRNA levels in blood leucocytes (BL) than in milk somatic cells (MSC), as well as lower SAA, Hp, and CRP and higher Cp and AGP concentrations in blood serum than in milk. In SRLV-infected goats, we found higher Fbγ and MAP28 and lower Cp expression in MSC than in BL, and higher SAA, Hp, Fb, and MAP28 and lower AGP concentrations in milk than in blood serum. Higher SAA and Hp expressions in BL and Hp expression in MSC were found in SRLV-infected goats. In SRLV-infected goats, we observed a higher concentration of SAA in blood serum, while in milk, lower SAA, Cp, and MAP28 and higher MAP34 concentrations were observed. The expression profiles of the studied genes differed between BL/serum and MSC/milk. The elevated SAA concentration in blood serum was accompanied by a decreased concentration of SAA and Cp in the milk of infected goats. No differences in the expression of the other studied genes may mean that the SRLV has the ability to evade the immune system, continuing to replicate. The elevated concentration of SAA in blood serum may promote viral multiplication. This higher concentration of SAA in blood serum and simultaneous reduced concentration of SAA and Cp in milk may be additive indicators of this infection.

Evaluation of alternatives to cautery disbudding of dairy goat kids using physiological measures of immediate and longer-term pain

We evaluated alternatives to cautery disbudding of goat kids using physiological measures of immediate and longer-term pain. Fifty Saanen doe kids were randomly assigned to 1 of 5 treatments (n = 10/treatment): (1) cautery disbudding (CAUT), (2) caustic paste disbudding (CASP), (3) liquid nitrogen disbudding (CRYO), (4) clove oil injected into the horn bud (CLOV), or (5) sham disbudding (SHAM). Serum cortisol and haptoglobin concentrations were measured from blood samples collected immediately before treatment (baseline) and at 15, 30, 60, and 120 min and then again at 6 and 24 h post-treatment. An infrared thermography camera was used to take images of the horn buds 24 h pre- and 24, 48, and 72 h post-treatment to measure skin temperature. Body weight was measured daily for 1 wk to assess weight change post-treatment. Images of the horn buds were taken at d 1, 2, and 7 and at 6 wk post-treatment to assess tissue damage and wound healing. Mean cortisol concentrations were elevated in CASP kids 1 h post-treatment relative to CAUT kids. Cortisol concentrations of CRYO kids were higher than those of CAUT kids 30 min post-treatment; concentrations for CLOV kids were similar to CAUT kids post-treatment. Mean haptoglobin concentrations were similar across treatments over time; however, CLOV kids had higher concentrations at 24 h post-treatment than all other treatments. Skin temperatures of CASP and CLOV kids were elevated relative to CAUT kids at all time points post-treatment, and all disbudded kids had skin temperatures above those of SHAM kids at 72 h post-treatment. Treatment did not influence weight gain. The CAUT kids had large, open wounds exposing bone; small scabs were still evident 6 wk post-treatment. The CASP kids had red and open, raw wounds that generated large eschars, apparent for up to 6 wk. The CRYO kids had closed, dry wounds initially, but over time lesions appeared that caused open wounds; small scabs were present 6 wk post-treatment. The CLOV kids had closed, dry wounds with blackened skin; healed skin and minimal scabs were present 6 wk post-treatment. Caustic paste and cryosurgical disbudding appeared to cause more pain compared with cautery disbudding; thus, these methods may not provide good alternatives to cautery disbudding. Clove oil appeared to cause a similar pain response as cautery disbudding and smaller wounds with earlier tissue repair; this method shows promise as an alternative to cautery disbudding.

Effect of steroid hormones on the innate immune response induced by Staphylococcus aureus in the goat mammary gland

The objective of this study was to compare the dynamics of innate immune components after intramammary infusion of Staphylococcus aureus (SA) under conditions of high oestrogen and high progesterone in goats. In one group ("E-group"), controlled internal drug release (CIDR) devices were inserted intravaginally from days -11 to -4. Prostaglandin F2α was administered immediately after removal of the CIDR device at day -3, and then oestradiol benzoate (E) was injected intramuscularly once a day from days -2 to 3. Heat-inactivated SA was then administered via intramammary infusion to the left udder at day 0, whilst only saline was infused to the right udder as a control. In a second group ("P-group"), CIDR devices were inserted intravaginally from days -3 to 7 and SA was infused at day 0 in the same way as in the E-group. The milk yield and the concentration of innate immune components (somatic cell count (SCC), lactoferrin (LF), S100A7 and goat ß-defensin 1 (GBD-1)) in the milk were measured. Milk yield decreased drastically in both SA and control udders in the E-group, whereas the P-group exhibited increased milk yield in both SA and control udders. SCC increased after SA infusion in both E- and P-groups, although it was higher in the E-group than in the P-group. There was no significant change in LF concentration in the E-group, but a decrease was observed in the P-group. Concentrations of S100A and GBD-1 were significantly increased after SA infusion in the E-group but not in the P-group. These results suggest that E enhances the innate immune response induced by SA in the goat mammary gland. This effect may be due to the reduction in milk yield and upregulation of innate immune components.

Acute phase proteins in healthy goats: establishment of reference intervals

Acute inflammatory processes can trigger increased production of acute phase proteins (APPs) that can be useful biomarkers of inflammation. APPs are diverse and include proteins involved in coagulation, opsonization, iron regulation, and limitation of tissue injury. Haptoglobin, serum amyloid A, and alpha-1 acid glycoprotein have been proposed as useful APPs in goats. APPs can differ markedly by species, therefore species-specific reference intervals and studies are necessary. The objective of this study was to determine species-specific reference intervals for 4 APPs in goats. Haptoglobin, serum amyloid A, lipopolysaccharide binding protein, and alpha-1 acid glycoprotein were measured in in 54 clinically normal adult goats. APPs were measured using goat-specific commercial enzyme-linked immunosorbent assay kits. Results were analyzed by 1-way analysis of variance to compare sexes and breeding status. Reference Value Advisor was used to calculate reference limits according to the IFCC-CLSI guidelines. Only 1 APP was found to vary in healthy animals; serum haptoglobin was increased in lactating animals and decreased in pregnant does in their second trimester when compared with open, nonlactating does. No sex-based differences were seen for any of the APPs measured. We report normal reference intervals for 4 serum APPs that may be useful as disease markers. Haptoglobin should be interpreted with caution in animals with unknown pregnancy status. Further studies are needed to determine whether these APPs are useful biomarkers in goat disease states.

Role of somatic cells on dairy processes and products: a review

Somatic cells are an important component naturally present in milk, and somatic cell count is used as an indicator of udder health and milk quality. The role of somatic cells in dairy processes and products is ill-defined in most studies because the role of these cells combines also the concomitance of physicochemical modifications of milk, bacterial count, and the udder inflammation in the presence of high somatic cell count. The aim of this review is to focus on the role of somatic cells themselves and of endogenous enzymes from somatic cells in milk, in dairy transformation processes, and in characteristics of final products overcoming biases due to other factors. The immune function of somatic cells in the udder defense and their protective role in milk will be primarily considered. Different characteristics of milk induced by various somatic cell counts, types, and their endogenous enzymes influencing directly the technological properties of milk and the final quality of dairy products will be discussed as well. By comparing methods used in other studies and eliminating biases due to other factors not considered in these studies, a new approach has been suggested to evaluate the effective role of somatic cells on dairy processes and products. In addition, this new approach allows the characterization of somatic cells and their endogenous enzymes and, in future research, will allow the clarification of mechanisms involved in the release of these components from somatic cells during dairy processes, particularly in cheese technologies.

Characterization of goat milk lactoferrin N-glycans and comparison with the N-glycomes of human and bovine milk

Numerous milk components, such as lactoferrin, are recognized as health-promoting compounds. A growing body of evidence suggests that glycans could mediate lactoferrin's bioactivity. Goat milk lactoferrin is a candidate for infant formula supplementation because of its high homology with its human counterpart. The aim of this study was to characterize the glycosylation pattern of goat milk lactoferrin. After the protein was isolated from milk by affinity chromatography, N-glycans were enzymatically released and a complete characterization of glycan composition was carried out by advanced MS. The glycosylation of goat milk lactoferrin was compared with that of human and bovine milk glycoproteins. Nano-LC-Chip-Q-TOF MS data identified 65 structures, including high mannose, hybrid, and complex N-glycans. Among the N-glycan compositions, 37% were sialylated and 34% were fucosylated. The results demonstrated the existence of similar glycans in human and goat milk but also identified novel glycans in goat milk that were not present in human milk. These data suggest that goat milk could be a source of bioactive compounds, including lactoferrin that could be used as functional ingredients for food products beneficial to human nutrition.

Detection of casein phosphopeptides in goat milk

The aims of this study were to profile casein phosphopeptides in goat milk, to accurately determine the site of phosphorylation, and to evaluate whether or not any of the casein phosphorylation patterns were specific to a given physiological condition. Goat milk, collected before and after experimental induction of endotoxin mastitis, was separated by SDS-PAGE. Casein bands were digested with trypsin and the resulting peptides were analyzed by nLC-MS/MS. Eight out of nine predicted tryptic phosphopeptides corresponding to 18 different phosphorylation sites were detected in αS1-, αS2-, and β-casein. Characterization of the phosphorylation sites illustrated the capability of tandem MS to accurately localize phosphorylated residues among a number of other putative sites. Despite an apparent lower abundance, almost all of the phosphopeptides were also detected in milk samples obtained from the goats following experimental induction of endotoxin mastitis. However, a tetra-phosphopeptide in αS2-casein was only observed in the milk samples obtained from healthy animals. The absence of this multiphosphopeptide in the mastitic goat milk samples could indicate changes in phosphorylation as a result of disease and potentially be used as a marker for milk quality. This study represents the first comprehensive analysis of casein phosphoproteome and reveals a much higher level of phosphorylation than previously demonstrated in goat milk.