Proteome and radioimmunoassay analyses of pituitary hormones and proteins in response to feed restriction of dairy cows

Effects of feeding level, milking frequency, and single injection of cabergoline on blood metabolites, hormones, and minerals around dry-off in dairy cows

This study aimed to investigate the effect of the different dry-off strategies based on reducing feeding level (normal vs. reduced energy density), reducing milking frequency (twice vs. once daily), and administration of a dopamine agonist after last milking (i.e. saline vs. cabergoline injection) on blood metabolites, hormones, and minerals around dry-off. In this experiment, 119 Holstein dairy cows were used in a 2 × 2 × 2 factorial arrangement. In the last week before dry-off, cows were allocated to 1 of the 4 possible dry-off strategies based on feeding level and milking frequency. Within 3 h after last milking, cows were injected with either saline or a D₂ dopamine agonist (cabergoline; Velactis, Ceva Santé Animale, Libourne, France; labeled for use only with abrupt dry-off, e.g., no preceding reduction in feeding level or milking frequency before last milking). After dry-off, all cows were fed the same dry cow diet and data collection continued for a week. Blood samples were collected from the coccygeal vein on d -9, -6, -5, -2, 1, 2, 5, and 7 relative to dry-off. Additionally, blood was sampled at 0, 3, and 6 h relative to injection of either cabergoline or saline, equivalent to d 0.125, 0.250, and 0.375 relative to last milking (dry-off). The reduced feeding level before dry-off caused reduced glucose and insulin concentrations as well as increased free fatty acid concentrations, particularly when reduced feeding level was combined with milking the cows 2× daily. The intramuscular injection of cabergoline caused the expected reduction in circulating prolactin concentrations. In addition, dopamine-agonist cabergoline induced an atypical simultaneous pattern of plasma metabolites (i.e., increased glucose and free fatty acid concentrations), hormones (i.e., reduced insulin and increased cortisol concentrations), and minerals (i.e., reduced calcium concentration), indicating that normal metabolic and mineral homeostatic regulations were hindered after the injection of ergot alkaloid cabergoline. In conclusion, reducing milking frequency seems the best management strategy to reduce milk production at dry-off among those tested in this study.

Effect of feed restriction on dairy cow milk production: a review

In the dairy cow, negative energy balance affects milk yield and composition as well as animal health. Studying the effects of negative energy balance on dairy cow milk production is thus essential. Feed restriction (FR) experiments attempting to reproduce negative energy balance by reducing the quantity or quality of the diet were conducted in order to better describe the animal physiology changes. The study of FR is also of interest since with climate change issues, cows may be increasingly faced with periods of drought leading to a shortage of forages. The aim of this article is to review the effects of FR during lactation in dairy cows to obtain a better understanding of metabolism changes and how it affects mammary gland activity and milk production and composition. A total of 41 papers studying FR in lactating cows were used to investigate physiological changes induced by these protocols. FR protocols affect the entire animal metabolism as indicated by changes in blood metabolites such as a decrease in glucose concentration and an increase in non-esterified fatty acid or β-hydroxybutyrate concentrations; hormonal regulations such as a decrease in insulin and insulin-like growth factor I or an increase in growth hormone concentrations. These variations indicated a mobilization of body reserve in most studies. FR also affects mammary gland activity through changes in gene expression and could affect mammary cell turnover through cell apoptosis, cell proliferation, and exfoliation of mammary epithelial cells into milk. Because of modifications of the mammary gland and general metabolism, FR decreases milk production and can affect milk composition with decreased lactose and protein concentrations and increased fat concentration. These effects, however, can vary widely depending on the type of restriction, its duration and intensity, or the stage of lactation in which it takes place. Finally, to avoid yield loss and metabolic disorders, it is important to identify reliable biomarkers to monitor energy balance.

Prepartum and Postpartum Feed Restrictions Affect Blood Metabolites and Hormones Reducing Colostrum and Milk Yields in Fat-Tailed Dairy Sheep

Simple Summary

Despite the fact that fat-tailed sheep raised for meat production are well known for being resilient to harsh environmental conditions such as pasture scarcity or low-quality feedstuffs, no studies regarding feed restriction have been performed on fat-tailed dairy sheep. In this study, prepartum feed restriction from week −5 to week −1 relative to parturition did not affect body weight. Similarly, postpartum feed restriction from week 1 to week 5 relative to parturition did not affect body weight. However, both prepartum and postpartum feed restrictions affected blood metabolites and hormones, which decreased both colostrum and milk yields postpartum.

Abstract

This study aimed to investigate the effect of prepartum and postpartum feed restriction on body weight (BW), blood metabolites, and hormones as well as colostrum and milk yields and compositions in fat-tailed dairy sheep. In this study, 20 multiparous and pregnant ewes were randomly allocated to either the control (Ctrl; n = 10) or the feed-restricted (FR; n = 10) groups from week −5 to week 5 relative to parturition. Despite dry matter intake being decreased in the FR group compared to the Ctrl throughout both prepartum and postpartum periods, no differences in BW were detected between groups in any of the studied periods. Feed restriction increased both free fatty acids and beta-hydroxybutyrate concentrations during both prepartum and postpartum periods. Similarly, feed restriction increased triglyceride concentration postpartum. Additionally, feed restriction increased insulin and growth hormone and decreased prolactin concentrations during both prepartum and postpartum periods. Feed restriction caused a decreased colostrum yield and a relative increase of the main colostrum components in the FR group. Similarly, milk yield decreased in the FR group compared to the Ctrl group, although milk components were not affected. In conclusion, feed restriction did not affect BW but decreased colostrum and milk yield in fat-tailed dairy sheep.

Low-Cost Localized Surface Plasmon Resonance Biosensing Platform with a Response Enhancement for Protein Detection

There are many potential applications for biosensors that can provide real-time analysis, such as environmental monitoring and disease prevention. In this study, we investigated a simple strategy for real-time protein detection, which had the advantages of affordability, fast response, portability, and ease of use. A robust quantification of protein interaction was achieved by combining capillary localized surface plasmon resonance (LSPR) sensors and complementary metal–oxide–semiconductor (CMOS) image sensors. Gold nanoparticles were modified on the inner wall of the capillary, which was used as a microfluidic channel and sensing surface. We functionalized one of the LSPR sensors using ligand bound to gold nanoparticle. Our proposed biosensing platform could be easily multiplexed to achieve high throughput screening of biomolecular interactions, and it has the potential for use in disposable sensors. Moreover, the sensing signal was enhanced by the extinction effect of gold nanoparticles. The experimental results showed that our device could achieve qualitative identification and quantitative measurement of transferrin and immunoglobulin G (IgG). As a field-portable and low-cost optical platform, the proposed LSPR biosensing device is broadly applicable to various protein binding tests via a similar self-assembly of organic ultrathin films.

Effect of reducing milk production using a prolactin-release inhibitor or a glucocorticoid on metabolism and immune functions in cows subjected to acute nutritional stress

When cows are unable to consume enough feed to support milk production, they often fall into severe negative energy balance. This leads to a weakened immune system and increases their susceptibility to infectious diseases. Reducing the milk production of cows subjected to acute nutritional stress decreases their energy deficit. The aim of this study was to compare the effects on metabolism and immune function of reducing milk production using quinagolide (a prolactin-release inhibitor) or dexamethasone in feed-restricted cows. A total of 23 cows in early/mid-lactation were fed for 5 d at 55.9% of their previous dry matter intake to subject them to acute nutritional stress. After 1 d of feed restriction and for 4 d afterward (d 2 to 5), cows received twice-daily i.m. injections of water (control group; n=8), 2mg of quinagolide (QN group; n=7), or water after a first injection of 20mg of dexamethasone (DEX group; n=8). Feed restriction decreased milk production, but the decrease was greater in the QN and DEX cows than in the control cows on d 2 and 3. As expected, feed restriction reduced the energy balance, but the reduction was lower in the QN cows than in the control cows. Feed restriction decreased plasma glucose concentration and increased plasma nonesterified fatty acid (NEFA) and β-hydroxybutyrate (BHB) concentrations. The QN cows had higher glucose concentration and lower BHB concentration than the control cows. The NEFA concentration was also lower in the QN cows than in the control cows on d 2. Dexamethasone injection induced transient hyperglycemia concomitant with a reduction in milk lactose concentration; it also decreased BHB concentration and decreased NEFA initially but increased it later. Feed restriction and quinagolide injections did not affect the blood concentration or activity of polymorphonuclear leukocytes (PMN), whereas dexamethasone injection increased PMN blood concentration but decreased the proportion of PMN capable of inducing oxidative burst. Incubation of peripheral blood mononuclear cells in serum harvested on d 2 of the restriction period reduced their ability to react to mitogen-induced proliferation, and injection of quinagolide or dexamethasone could not alleviate this effect. This experiment shows that prolactin-release inhibition could be an alternative to dexamethasone for reducing milk production and energy deficit in cows under acute nutritional stress, without disturbing immune function.

Proteomics and the search for welfare and stress biomarkers in animal production in the one-health context

Stress and welfare are important factors in animal production in the context of growing production optimization and scrutiny by the general public.

The dopamine antagonist domperidone increases prolactin concentration and enhances milk production in dairy cows

In previous studies, our team showed that the inhibition of prolactin (PRL) secretion by the dopamine agonist quinagolide reduces milk production in dairy cows. The objective of this study was to determine the effects of administration of a dopamine antagonist on basal and milking-induced PRL concentrations in blood and on milk production during positive energy balance and feed restriction in dairy cows. Eighteen mid-lactation Holstein cows received daily s.c. injections of either domperidone (300 mg, DOMP, n=9) or the vehicle, canola oil (CTL, n=9), for 5 wk. During wk 5, all cows were fed at 65% of their dry matter intake in the previous week. Blood and milk samples were collected before (for blood) and during (for milk) the a.m. milking thrice weekly from d -9 to 41 (8d after the last injection). In addition, blood samples were collected during the a.m. milking on d -1 (before the first injection), and on d 1, 28, and 34. Basal PRL concentration was similar in both groups before the start of the treatments. Domperidone injections caused a gradual increase in basal PRL concentration. Feed restriction reduced basal PRL concentration in both the CTL and DOMP cows, but PRL concentration remained higher in the DOMP cows. Prolactin concentration remained elevated in the DOMP cows 7d after the last injection. The milk concentration of PRL increased during the DOMP treatment, but the increase was smaller than that observed in serum. In the CTL cows, the milking-induced PRL release above the premilking concentration was similar on d -1, 1, and 28 but was reduced during feed restriction. In the DOMP cows, the milking-induced PRL release was similar on d -1 and 1 but was reduced on d 28 and 34. Milk production was similar for both groups before the treatments started but was greater in the DOMP cows during the treatment period, at 2.9 ± 0.6 and 2.4 ± 0.6 kg/d greater during wk 3 and 4 of treatment, respectively. Milk production declined in both groups during feed restriction but remained higher in the DOMP cows. Milk production became similar again for both groups after the last injection. In addition, dry matter intake was increased by DOMP. These results support the hypothesis that PRL is galactopoietic in dairy cattle.

Comparative secretome analysis of rat stomach under different nutritional status

Obesity is a major public health threat for many industrialised countries. Bariatric surgery is the most effective treatment against obesity, suggesting that gut derived signals are crucial for energy balance regulation. Several descriptive studies have proven the presence of gastric endogenous systems that modulate energy homeostasis; however, these systems and the interactions between them are still not well known. In the present study, we show for the first time the comparative 2-DE gastric secretome analysis under different nutritional status. We have identified 38 differently secreted proteins by comparing stomach secretomes from tissue explant cultures of rats under feeding, fasting and re-feeding conditions. Among the proteins identified, glyceraldehyde-3-phosphate dehydrogenase was found to be more abundant in gastric secretome and plasma after re-feeding, and downregulated in obesity. Additionally, two calponin-1 species were decreased in feeding state, and other were modulated by nutritional and metabolic conditions. These and other secreted proteins identified in this work may be considered as potential gastrokines implicated in food intake regulation.

BIOLOGICAL SIGNIFICANCE

The present work has an important impact in the field of obesity, especially in the regulation of body weight maintenance by the stomach. Nowadays, the most effective treatment in the fight against obesity is bariatric surgery, which suggests that stomach derived signals might be crucial for the regulation of the energy homeostasis. However, until now, the knowledge about the gastrokines and its mechanism of action has been poorly elucidated. In the present work, we had updated a previously validated explant secretion model for proteomic studies; this analysis allowed us, for the first time, to study the gastric secretome without interferences from other organs. We had identified 38 differently secreted proteins comparing ex vivo cultured stomachs from rats under feeding, fasting and re-feeding regimes. The results in the present article provide novel targets to study the role of the stomach in body weight and appetite regulation, and suggest new potential therapeutic targets for treating obesity.

Metabolism of albumin after continuous venovenous hemofiltration in patients with systemic inflammatory response syndrome

BACKGROUND

The systemic inflammatory response syndrome (SIRS) is characterized by a hypercatabolic state induced by inflammatory mediators. Continuous venovenous hemofiltration (CVVH) stabilizes the internal environment but also aggravates loss of amino acids. The effect of CVVH on protein dynamics is largely unknown. We adopted the stable isotopic tracer technology to investigate how CVVH changed serum albumin metabolism.

METHODS

Twenty SIRS patients were randomized into low- (2000 mL/h) and high- (4000 mL/h) volume CVVH groups according to the rate of replacement fluid. Eight patients with abdominal infection matched for age, sex, and laboratory index served as controls. Consecutive arterial blood samples were drawn during a primed-constant infusion of two stable isotopes to determine the albumin fractional synthesis rate (FSR) and fractional breakdown rate (FBR).

RESULTS

Before treatment, there was no significant difference of FSR and FBR among 3 groups. After CVVH, the albumin FSR in high- and low-volume groups was 7.75±1.08% and 7.30±0.89%, respectively, both higher than in the control (5.83±0.94%). There was no significant difference in albumin FBR after treatment.

CONCLUSIONS

Protein dynamic indicators could reflect protein synthesis and breakdown state directly and effectively. CVVH increased albumin synthesis, while the breakdown rate remained at a high level independently of the CVVH rate.

Effects of feed restriction and prolactin-release inhibition at drying off on metabolism and mammary gland involution in cows

A cow's risk of acquiring a new intramammary infection during the dry period increases with milk production at drying off and decreases as mammary gland involution progresses. A method commonly used to reduce milk production is a drastic reduction in feed supply in the days that precede drying off. Milk production can also be reduced by inhibiting the lactogenic signal driven by prolactin (PRL). This study aimed to compare the effects of these 2drying-off procedures on metabolism, immunity, and mammary gland involution in cows. A total of 24Holstein cows in late lactation were assigned to 1 of 3treatments based on milk yield, somatic cell count, and parity. The cows were fed a lactation diet until drying off (control; n=8), only dry hay during the last 5d before drying off (DH; n=8), or the same lactation diet as the control cows but with twice-daily i.m. injections of 4mg of quinagolide, a specific inhibitor of PRL release, from 5d before drying off until 13d after (QN; n=8). Quinagolide induced a decrease in PRL concentration in blood and in milk and mammary secretions on all the injection days. Interestingly, PRL was also depressed in the blood and milk of the hay-fed cows before drying off. Both the QN and DH treatments induced a decrease in milk production, which averaged 17.9 and 10.1kg/d for the QN and DH cows, respectively, at drying off in comparison with 24.8kg/d for the control cows. Both BSA concentration and Na(+)-to-K(+) ratio increased faster in the mammary secretions of both the DH and QN cows than in those of the control cows, whereas citrate-to-lactoferrin ratio, another indicator of involution rate, decreased faster. The DH treatment decreased blood concentrations of glucose and most amino acids and increased blood concentrations of β-hydroxybutyrate and nonesterified fatty acids. Quinagolide increased blood glucose but did not affect the other metabolites. The serum harvested on d-1 from the hay-fed cows reduced peripheral blood mononuclear cell proliferation and IL-4 production, whereas the serum from the quinagolide-treated cows had no effect. In conclusion, this experiment shows that PRL-release inhibition could be a new alternative for reducing milk production before drying off and for hastening mammary gland involution without disturbing the metabolism of the cow.

Successful use of a gonadotropin-releasing hormone (GnRH) analog for the treatment of tertiary hypogonadism (GnRH deficiency) in a 5-year-old Belgian Blue bull

A bull was referred for a progressive oligoasthenotheratozoospermia that resulted in a unsuitable seminal quality for the cryopreservation. Breeding soundness evaluation results suggested gonadal dysfunction. Because of the lack of normal ranges for these hormones in the bull, in this study, the hypogonadism and the site of the dysfunction (hypothalamus) were diagnosed by the gonadotropin-releasing hormone (GnRH) stimulation test. The evaluation of pituitary and testicular responsiveness by a GnRH stimulating test revealed a responsiveness of the pituitary and testis, thus a secondary hypogonadism (hypothalamic hypogonadism) was postulated and a therapeutic approach based on the subcutaneous administration of GnRH analog was attempted. An increase in semen volume, concentration and sperm characteristics were detected 9 weeks after the start of the treatment, corroborating the hypothalamic origin of the disease and the useful of the GnRH therapy.