Associations among milk production traits and glycosylated haemoglobin in dairy cattle: importance of lactose synthesis potential

Abstract Glucose is the major precursor of lactose synthesis in the mammary gland. Lactose the major carbohydrate and osmolyte of milk, controls milk volume and its concentration. Glycosylated haemoglobin (HbG) is a retrospective measure of mean blood glucose level and it is largely unaffected by recent physiological conditions and environmental events. The purposes of this study were to determine the correlations between lactose traits and other milk production traits in dairy cattle and to investigate whether HbG level can be correlated with milk and lactose production traits. Here, HbG percentage, milk and lactose production traits including milk yield, lactose, protein, SNF, total solid and fat percentages and yields were measured in 485 second calved Iranian Holstein cattle. Statistically significant negative correlations were established between HbG and milk yield (r=−0.88), lactose yield (r=−0.83), SNF yield (r=−0.81), protein yield (r=−0.79) and total solid yield (r=−0.74). Positive correlations were established between lactose yield and milk (r=0.96), protein (r=0.81), SNF (r=0.92) and total solid (r=0.79) yields. The negative correlation between HbG and milk and total lactose production is probably related to the higher glucose demands in the lactating mammary gland of more productive cows. The positive correlation between lactose yield and milk, protein, SNF and total solid yield indicates that the level of lactose synthesis influences milk production traits in ways other than merely via its osmolytic action

Assessment of calcium, phosphorus, magnesium, vitamin D and PTH levels in sera of lame horses

Abstract Background Minerals play vital roles in physiologic processes. Calcium, phosphorus and magnesium are common minerals. Secretion, absorption and homeostasis of these minerals are affected by associations between the active vitamin D and parathyroid hormone (PTH). Objective The aim of this study was to assess concentrations of vitamin D, PTH and minerals, such as calcium, phosphorus and magnesium in horse sera, as well as associations of these values with lameness in horses. In the references, the reasons for lameness can be deficiency and imbalance of minerals, and clinical observations also confirm this and there is still not enough information regarding the relationship between mineral imbalance and lameness of horses. The prominent forms of lameness include navicular syndrome, back pain, splints, ring bone, side bone, non‐infectious arthritis and bucked shins. Deficiency and inadequacy of calcium, phosphorous and magnesium have been regarded as predisposing and aggravating factors of the aforementioned diseases. Materials and methods This cross‐sectional study was carried out on 60 horses, including 30 lame and 30 healthy adult horses, summer to fall 2021. Levels of calcium, phosphorus, magnesium, vitamin D and PTH were assessed in sera using automatic analyser, atomic absorption spectroscopy and commercially available kits. Results The average level of calcium was higher healthy horses than lame horses in the two seasons (p < 0.001). The average level of inorganic phosphorus in horses was higher in summer than autumn (p < 0.001). The mean magnesium concentration in healthy horses was greater than lame horses in the two seasons (p < 0.01). In this study, the mean PTH concentration in healthy horses was lower in fall than summer (p < 0.05). Conclusion The low average levels of calcium and magnesium in lame horses in the two seasons indicate critical roles of calcium and magnesium in the normal function of the horse musculoskeletal system as well as prevention of lameness

Antioxidant, ACE-inhibitory and antimicrobial activities of Kluyveromyces marxianus protein hydrolysates and their peptide fractions

Background: There has been some evidence that proteins are potentially excellent source of antioxidants, antihypertensive and antimicrobial peptides and enzymatic hydrolysis is an effective method to release these peptides from protein molecules. The functional properties of protein hydrolysates depends on the protein substrate, the specificity of the enzymes, the conditions used during proteolysis, degree of hydrolysis, and the nature of peptides released including molecular weight, amino acid composition, and hydrophobicity. Context and purpose of this study: The biomass of Kluyveromyces marxianus was considered as a source of ACE inhibitory, antioxidant and antimicrobial peptides. Results: Autolysis and enzymatic hydrolysis were completed respectively, after 96 h and 5 h. Overall, trypsin (18.52% DH) and chymotrypsin (21.59% DH) treatments were successful in releasing antioxidant and ACE inhibitory peptides. Autolysate sample (39.51% DH) demonstrated a poor antioxidant and ACE inhibitory activity compared to trypsin and chymotrypsin hydrolysates. The chymotrypsin 3-5 kDa (301.6±22.81 μM TEAC/mg protein) and trypsin< 3 kDa (280.16±39.16) permeate peptide fractions showed the highest DPPH radical scavenging activity. The trypsin <3 kDa permeate peptide fraction showed the highest ABTS radical scavenging (1691.1±48.68 μMTE/mg protein) and ACE inhibitory (IC50=0.03±0.001 mg/ml) activities. The fraction (MW=5-10 kD) obtained after autolysis treatment showed antibacterial activity against St. aureus and Lis. monocytogenes in well diffusion screening. The minimum inhibitory concentration (MIC) value was 13.3 mg/ml against St. aureus and Lis. monocytogenes calculated by turbidimetric assay and it showed bactericidal activity against St. aureus at 21.3 mg/ml protein concentration. Conclusions: Taken together, the results of this study reveal that K. marxianus proteins contain specific peptides in their sequences which can be released by enzymatic hydrolysis and autolysis

Association of polymorphism of the ß(1, 4)-galactosyltransferase-I gene with milk production traits in Holsteins

The b(1,4)-galactosyltransferase-I gene (b4galt1) encodes the catalytic part of the enzyme lactose synthase, responsible of lactose synthesis in the mammary gland. The complete coding region of the gene was screened for the presence of allelic variation among a sample of 1,200 Iranian Holstein cows, using PCR-SSCP technique followed by sequencing. Nine polymorphic nucleotide sites were identified- one in exons I and VI, two in exons II and III, and three in exon V. Altogether 18 different genotypes were assigned. Statistical analysis showed that the genotypes of B4GALT1 significantly affect milk, lactose, protein and total solid productions in both the first and second lactation (P\0.001). Variance component analysis considering restricted maximum likelihood showed that the major factor making differences in milk, lactose, protein and total solid productions among the studied cow is the b4galt1 genotype. We concluded that the b4galt1 gene is potentially associated with milk production traits in dairy cows and should be considered for further studies on genetics of the milk production traits

Production of antioxidant and ACE-inhibitory peptides from Kluyveromyces marxianus protein hydrolysates: Purification and molecular docking

Kluyveromyces marxianus protein hydrolysates were prepared by two different sonicated-enzymatic (trypsin and chymotrypsin) hydrolysis treatments to obtain antioxidant and ACE-inhibitory peptides. Trypsin and chymotrypsin hydrolysates obtained by 5 h, exhibited the highest antioxidant and ACE-inhibitory activities. After fractionation using ultrafiltration and reverse phase high performance liquid chromatography (RP-HPLC) techniques, two new peptides were identified. One fragment (LL-9, MW = 1180 Da) with the amino acid sequence of Leu-Pro-Glu-Ser-Val-His-Leu-Asp-Lys showed significant ACE inhibitory activity (IC50 = 22.88 μM) while another peptide fragment (VL-9, MW = 1118 Da) with the amino acid sequence of Val-Leu-Ser-Thr-Ser-Phe-Pro-Pro-Lys showed the highest antioxidant and ACE inhibitory properties (IC50 = 15.20 μM, 5568 μM TE/mg protein). The molecular docking studies revealed that the ACE inhibitory activities of VL-9 is due to interaction with the S2 (His513, His353, Glu281) and S′1 (Glu162) pockets of ACE and LL-9 can fit perfectly into the S1 (Thr345) and S2 (Tyr520, Lys511, Gln281) pockets of ACE. Keywords: K. marxianus, Bioactive peptides, Antioxidant, ACE inhibitory, Protein hydrolysat

Effects of Medium-Voltage Electrical Stimulation on Postmortem Changes in Fat-Tailed Sheep

Abstract: Effects of different medium-voltage electrical stimulation (ES) and ageing on postmortem changes in longissimus dorsi muscle of the fat-tailed sheep were studied. Fifteen male animals were divided into 5 equal groups (n = 3) including: T 1 (control, without ES), T 2 (100 V/30 s), T 3 (100 V/60 s), T 4 (150 V/30 s), and T 5 (150 V/60 s) with fixed frequency of 50 Hz. Five minutes after sticking, the carcasses were stimulated in order of the treatments. After normal processing, they were kept at 6 • C for 14 d. ES accelerated the glycolytic rate resulting in a significant fast fall in pH (P &lt; 0.05) during the 1st 6-h postmortem (PM) with a gradual decline until 24-h PM, and a simultaneous significant reduction in adenosine triphosphate (ATP) content (P &lt; 0.05). There was a significant (P &lt; 0.05) decline in the total calpain activity during the 1st 6-h PM. The muscles from ES carcasses had significantly (P &lt; 0.05) lower water holding capacity (WHC) than those from nonstimulated ones. Ageing revealed a significant (P &lt; 0.05) effect on the reduction of WHC. No significant difference was found for the mean value of the muscle color (L * , a * , and b * ) in all treatment groups during ageing (P &gt; 0.05). The results of free amino acid (FAA) content and myofibrillar fragmentation index (MFI) revealed a significant improvement of proteolysis and tenderness by ES and ageing (P &lt; 0.05). In the present study, higher voltage/duration (150 V/60 s) showed greater effects and significantly accelerated glycolysis, pH decline, and ATP depletion and thus decreased the time for rigor completion and improved the tenderness

Evaluation the Effect of Saffron Aqueous Extract on Oxidative Stress Parameters and Important Biochemical Enzymes of Liver Tissue in Streptozotocin-Induced Diabetic Rats

Background and Aim: Medicinal plants possessing antioxidant activity may reduce oxidative stress and improve the functions of various organs that affected by hyperglycemia. The aim of the present study was to evaluate the effects of saffron aqueous extract (SAE) administration to diabetic rats by measuring the oxidative stress parameters and important biochemical enzymes in liver tissue. Materials and Methods: 72 hours after STZ administration (60 mg/kg body weight), the animals with fasting blood glucose over of 250 mg/dl were considered to be diabetic rats and experimental groups were: control (1), control drug (2), diabetes (3) and diabetes drug (4). The treatment was started on the 7th day after STZ injection with i.p injection of SAE (200mg/kg body weight), five doses and weekly to groups 2 and 4. At the end of the experimental period, biochemical factors were measured after bleeding and harvesting of tissues. Findings: Results indicated the perturbation in the activity of important liver enzymes in diabetic group (3) and SAE adjusted and normalized their levels activity. In addition, SAE with increases in the activity of antioxidant enzymes alleviated diabetes induced oxidative stress and thus reduced MDA levels in group 4 compared to group 3. Conclusion: SAE is not only useful in the controlling of blood glucose, but also has antioxidant potential to protect the liver tissue of diabetic rats against damage caused by hyperglycemia-induced oxidative stress