Altering prolactin concentrations in sows

Prolactin has a multiplicity of actions, but it is of particular importance in gestating and lactating animals. In sows, it is involved in the control of mammary development and also holds essential roles in the lactogenic and galactopoietic processes. Furthermore, low circulating concentrations of prolactin are associated with the agalactia syndrome. The crucial role of prolactin makes it important to understand the various factors that can alter its secretion. Regulation of prolactin secretion is largely under the negative control of dopamine, and dopamine agonists consistently decrease prolactin concentrations in sows. On the other hand, injections of dopamine antagonists can enhance circulating prolactin concentrations. Besides pharmacologic agents, many other factors can also alter prolactin concentrations in sows. The use of Chinese-derived breeds, for instance, leads to increased prolactin concentrations in lactating sows compared with standard European white breeds. Numerous husbandry and feeding practices also have a potential impact on prolactin concentrations in sows. Factors, such as provision of nest-building material prepartum, housing at farrowing, high ambient temperature, stress, transient weaning, exogenous thyrotropin-releasing factor, exogenous growth hormone-releasing factor, nursing frequency, prolonged photoperiod, fasting, increased protein and/or energy intake, altered energy sources, feeding high-fiber diets, sorghum ergot or plant extracts, were all studied with respect to their prolactinemic properties. Although some of these practices do indeed affect circulating prolactin concentrations, none leads to changes as drastic as those brought about by dopamine agonists or antagonists. It appears that the numerous factors regulating prolactin concentrations in sows are still not fully elucidated, and that studies to develop novel applicable ways of increasing prolactin concentrations in sows are warranted.

Relative prolactin-to-progesterone concentrations around farrowing influence colostrum yield in primiparous sows

In swine, colostrum production is induced by the drop of progesterone (P4) concentrations which leads to the prepartum peak of prolactin (PRL). PRL regulates mammary cell turnover and stimulates lacteal nutrient synthesis. P4 inhibits PRL secretion and downregulates the PRL receptor in the mammary gland. The aim of the present study was to determine if the relative prepartum concentrations of P4 and PRL (PRL/P4 ratio) influence sow colostrum production. The performance of 29 Landrace × Large White primiparous sows was analyzed. Colostrum yield was estimated during 24 h starting at the onset of parturition (T0) using litter weight gains. Colostrum was collected at T0 and 24 h later (T24). Repeated jugular blood samples were collected during the peripartum period, that is, from -72 to +24 h related to farrowing and were assayed for P4 and PRL. Sows were retrospectively categorized in 2 groups according to their PRL/P4 ratio 24 h before farrowing being either <2 (low PRL/P4, n = 16) or >3 (high PRL/P4, n = 13). During the peripartum period, the circulating concentrations of P4 were lower (P < 0.05) and those of PRL tended to be greater (P < 0.10) in high PRL/P4 compared with low PRL/P4 sows. Colostrum yield was greater in high PRL/P4 compared with low PRL/P4 sows (4.11 vs 3.48 kg [root mean square error = 0.69], P < 0.05). Colostrum composition (dry matter, energy, protein, lipid, and lactose contents) and IgG and IgA concentrations did not differ between the 2 groups of sows (P > 0.10). The Na/K ratio in colostrum 24 h after the onset of farrowing was lower in high PRL/P4 compared with low PRL/P4 sows (P < 0.05). Piglet mortality between birth and T24 averaged 10.0% in low PRL/P4 litters and 7.0% in high PRL/P4 litters (P = 0.29). In conclusion, a greater PRL/P4 ratio 24 h prepartum, characterized by lower P4 concentrations and a trend for greater PRL concentrations peripartum, led to increased colostrum yield in primiparous sows.

Do gastroenterologists monitor their patients taking 5-amino-salicylates following initiation of treatment

BACKGROUND

5-Amino salicylate (5-ASA) medications may rarely be associated with a significant decline in renal function and interstitial nephritis. British Society of Gastroenterology guidelines advise regular renal function monitoring for patients taking these drugs.

AIM

To assess whether gastroenterologists in Kent were following best practice guidelines regarding the monitoring of their patients on 5-ASA therapy.

METHODS

Using longitudinal community and regional pathology databases for the Kent population, our renal unit regularly screens a total population of 300 000 for evidence of renal disease. The data extracted are analysed using an automated computerised system to identify patients requiring intervention for kidney disease. All patients taking 5-ASA medication were identified from a population of 300 000. The pathology database was studied to identify the patients on 5-ASA treatment and whether they had had renal function tests.

RESULTS

800 adult patients were identified taking 5-ASA therapy. 612 patients received 5-ASAs for 3 months or more, and these were included in the final analysis. 293 patients had no renal function checks while on treatment. 79 patients had renal function tests less than once every 4 years and 36 patients once every 2-4 years. 204 patients had renal function measurements in 50% or more of years of treatment, of whom 116 were checked every year. Some patients were started on treatment with abnormal results at baseline and some with identified kidney disease continued on their 5-ASAs.

CONCLUSIONS

The majority of patients receiving 5-ASA compounds do not have regular renal function monitoring. Clinicians are failing to follow best practice guidelines.

Plasma amino acids, prolactin, insulin and glucose concentrations in lactating sows following venous infusion of isoleucine, leucine, lysine, threonine or valine

de Ridder, K. A. G., Farmer, C., de Lange, C. F. M., Shoveller, A. K. and Luimes, P. H. 2014. Plasma amino acids, prolactin, insulin and glucose concentrations in lactating sows following venous infusion of isoleucine, leucine, lysine, threonine or valine. Can. J. Anim. Sci. 94: 323–330. The amino acid supply to lactating sows affects their milk yield, and the current study aims at establishing whether this is mediated via increases in concentrations of insulin and prolactin, two hormones that are important for lactation. Six multiparous Yorkshire sows (252.8±18.5 kg body weight) were fitted with an ear vein catheter and were used in a 6×6 Latin square design experiment from days 7 to 10 of lactation (am and pm infusions on 3 consecutive days). Sows were fed a commercial corn and soybean meal diet (17.1% crude protein) three times daily (1.5 kg at 0600 and 1200, 3.0 kg at 1830). Starting 2 h after the 0600 or 1200 feeding, sows received an infusion of saline (control), isoleucine, leucine, lysine, threonine or valine at a rate of 33 mL min−1during 30 min. The infused dose was equivalent to 18±0.9% of true ileal digestible intake for each of the amino acids. Serial blood samples were taken, starting 30 min prior to infusion and until 240 min after infusion. Plasma concentrations of amino acids, prolactin, insulin, and glucose were determined. Data were analyzed as repeated measurements and also using areas under the curve. Intravenous infusion with each of the five amino acids studied increased the corresponding free plasma amino acid concentrations (P<0.05). However, concentrations of prolactin, insulin, and glucose were not affected by infusion of any of the amino acids studied (P>0.10). Therefore, supplying intravenously 18% of the daily intake of isoleucine, leucine, lysine, threonine or valine brings about expected increases in amino acids, but does not alter the short-term response in prolactin, insulin or glucose concentrations of lactating sows.

Colostrum yield and piglet growth during lactation are related to gilt metabolic and hepatic status prepartum

It was hypothesized that colostrum production could be influenced by sow peripartum endocrine, metabolic, and hepatic status. The plant extract silymarin was shown to influence endocrine and hepatic status in several species. The aims of the present study were to investigate the effects of silymarin intake during late pregnancy on sow hormonal and hepatic status and to determine whether relations exist between sow hepatic and metabolic status during the peripartum period and colostrum yield and piglet performances during lactation. From d 107 of pregnancy until farrowing, nulliparous sows were either fed 12 g/d of silymarin (SIL; n = 15) or no treatment (Control; n = 12). Piglet BW was recorded directly after birth, 24 h after birth of the first piglet, and at 7, 14, and 21 d of lactation. Blood samples were collected from sows on d 107 and 109 of pregnancy, daily from d 111 of pregnancy until d 2 of lactation, and on d 7 and 21 of lactation. They were assayed for endocrine, metabolic, and hepatic variables. Colostrum yield was estimated during 24 h starting at the onset of farrowing. Silymarin did not influence colostrum yield (3.7 ± 0.3 kg) or gross composition (P > 0.10), nor did it affect serum prolactin concentrations or plasma concentrations of progesterone, estradiol-17β, or cortisol (P > 0.10). Mean litter BW gain was lower (P < 0.05) during the first week and tended (P < 0.10) to be lower during the second week of lactation in litters from SIL sows. Silymarin had no effect on plasma concentrations of aspartate transaminase, alanine transaminase, γ-glutamyl transferase (γ-GT), alkaline phosphatase, or total cholesterol (P > 0.10). Colostrum yield was positively correlated with urea (r = 0.50; P = 0.01) and creatinine (r = 0.43; P = 0.03) concentrations in sows on the day before farrowing. Mean litter BW gain over 2 wk was negatively correlated with concentrations of β-hydroxybutyric acid (r = -0.50; P = 0.01) and γ-GT (r = -0.42; P = 0.03) on the day before farrowing and was positively correlated with urea concentrations on the day before farrowing (r = 0.54; P = 0.01). In conclusion, at the dose of 12 g/d, silymarin did not influence prolactin concentrations or the hepatic status of sows, had no impact on colostrum production, and decreased litter BW gain in early lactation. Colostrum yield and litter performance during lactation were correlated with some markers of sow metabolic and hepatic status measured during the prepartum period.

Effects of the plant extract silymarin on prolactin concentrations, mammary gland development, and oxidative stress in gestating gilts

The impacts of supplementing the diet of gestating gilts twice daily with 4 g of the plant extract silymarin on circulating hormonal concentrations, oxidative status, mammary development, and mammary gene expression at the end of gestation were determined. Gilts were fed conventional diets during gestation and on d 90 they were assigned as controls (CTL; n = 16) or treated (TRT; n = 17) animals. Treatment consisted of providing 4 g of silymarin twice daily until d 110, at which time all gilts were slaughtered to collect mammary tissue for compositional analyses and measures of gene expression and oxidative status, and liver and corpora lutea for measures of oxidative stress variables. Blood samples for hormonal assays and evaluation of oxidative stress biomarkers were obtained on d 89, 94, and 109 of gestation. Silymarin increased (P = 0.05) circulating concentrations of prolactin over all samples in the repeated in time analysis. In separate analyses for each sampling time, prolactin concentrations in TRT gilts tended (P < 0.10) to be greater than in CTL gilts on d 94 of gestation. Repeated in time analysis also revealed that silymarin reduced (P ≤ 0.05) plasmatic accumulation of biomarkers of oxidative damage to protein (protein carbonyls) between d 89 and 109. There was no effect (P > 0.10) of treatment on progesterone, estradiol, leptin, or 8-hydroxy-2'-deoxyguanosine concentrations. Percent fat in mammary parenchyma was greater (P ≤ 0.05), percent protein was lesser (P ≤ 0.05), and concentrations of both RNA (P ≤ 0.01) and DNA (P < 0.05) were lesser in TRT than CTL gilts. Mammary parenchyma from TRT gilts had lower (P ≤ 0.05) mRNA abundance for STAT5A and leptin and tended to have lower (P ≤ 0.10) abundance for STAT5B than CTL gilts. Silymarin reduced (P ≤ 0.001) protein carbonyls concentrations in liver of TRT gilts. No effect of treatment was observed on antioxidant gene expression and enzymatic activities in liver samples while total superoxide dismutase activity tended to be higher (P ≤ 0.10) in the corpora lutea of TRT animals when compared with CTL. This is the first demonstration that, in female pigs, silymarin can increase prolactin concentrations and protect against oxidative stress, yet the increase in prolactin was not enough to have beneficial effects on mammary gland development in late gestation.

Impact of diet deprivation and subsequent overallowance during gestation on mammary gland development and lactation performance

The impacts of diet deprivation and subsequent overallowance during gestation on mammary gene expression and development and lactation performance were determined. Gilts were reared under a conventional (control, CTL; n = 59) or an experimental (treatment, TRT; n = 56) dietary regimen during gestation. The experimental regimen provided 70% (restriction diet, RES) and 115% (overallowance diet, OVER) of the protein and DE contents provided by the CTL diet. The RES diet was given during the first 10 wk of gestation followed by the OVER diet until farrowing. Some gilts (14 CTL and 14 TRT) were slaughtered on d 110 of gestation, and the others were allowed to farrow. Of these remaining sows, 28 (14 CTL and 14 TRT) were slaughtered on d 21 of lactation, and the rest underwent a second lactation. At each slaughter, mammary tissue was collected for compositional analyses and assessment of gene expression. Milk samples were collected on d 17 of the first lactation. Litter size was standardized to 11 ± 1, and piglets were weighed weekly until d 18 in both parities. The BW and back fat thickness of TRT first-parity sows were less than those of CTL sows in gestation (P < 0.05), and their BW was also less in lactation (P < 0.05). The BW of TRT second-parity sows was still less at mating (P < 0.05) and tended to be less on d 1 of lactation (P < 0.10) compared with CTL sows. There were no differences in piglet growth between CTL and TRT litters in either parity, yet mammary development and mammary gene expression were affected by treatment. There was less parenchymal tissue (P < 0.01) at the end of the first gestation in TRT than in CTL sows, but parenchymal tissue composition was not altered by treatment. Relative abundance of IGF-1 (P < 0.05), ornithine decarboxylase (P < 0.05), signal transducer and activator of transcription 5B (P < 0.05), and whey acidic protein (WAP, P < 0.01) genes in parenchyma at the end of the first gestation was lower in TRT than in CTL sows, and the effect on WAP genes was still present at the end of the first lactation (P < 0.01). Mammary composition at the end of the first lactation and milk composition were unaffected by treatment. In conclusion, feed deprivation and subsequent overallowance in gestation had unfavorable effects on sow BW, back fat, mammary development, and mammary gene expression at the end of gestation, but piglet growth rate over the 2 parities was not affected.

Short Communication: Effect of silymarin (Silybum marianum) treatment on prolactin concentrations in cyclic sows

Loisel, F., Quesnel, H. and Farmer, C. 2013. Short Communication: Effect of silymarin (Silybum marianum) treatment on prolactin concentrations in cyclic sows. Can. J. Anim. Sci. 93: 227–230. An extract (silymarin) from the plant Silybum marianum (milk thistle) was shown to increase circulating concentrations of prolactin in cycling rats. A dose-response study was undertaken to determine if silymarin does have hyperprolactinemic properties in cycling swine. Forty-four weaned sows were allotted to four groups receiving 0, 1, 2 or 4 g d−1 of silymarin over a period of 8 d. Blood samples were obtained on days 1 (first day of treatment starting 24 to 48 h after the onset of the standing estrus), 2, 3, and 9. Prolactin, progesterone, estradiol-17β and leptin concentrations were determined. Silymarin did not increase prolactin concentrations at any of the doses studied, nor did it affect concentrations of the other hormones (P>0.1).

Acceptability of digital anal cancer screening examinations in HIV-positive homosexual men

OBJECTIVES

Anal cancer is more common in HIV-positive homosexual men than in HIV-negative homosexual men and the general population. Earlier diagnosis leads to improved prognosis. We aimed to determine if regular anal inspection and digital examination of asymptomatic homosexual men attending for routine HIV care were acceptable and to record the rate of referral for diagnosis of potentially malignant anal lesions.

METHODS

We offered anal examinations to consecutive homosexual men with HIV infection aged ≥ 35 years during their routine HIV clinic visits, aiming to complete three examinations over a 12-month period. Acceptability questionnaires were completed at baseline and after each examination and doctors recorded examination findings and all resulting interventions. Hospital referral outcomes were collected and interventions were costed using the Australian Medical Benefits Schedule.

RESULTS

Of 142 men who were offered enrolment in the study, 102 [72%; 95% confidence interval (CI) 64-79%] participated. Following the initial anal examinations, four men were referred to surgeons. Cancer was excluded in three men (3%; 95% CI 1-8%) and one was diagnosed with anal squamous cell carcinoma (SCC). Three men had anoscopy performed at the time and two were referred for colonoscopy. Ninety-eight per cent (95% CI 93-100%) of respondents said that they would probably have the examination next time. The intervention was estimated to cost approximately Australian $16 per examination.

CONCLUSIONS

Regular anal digital examinations are an acceptable and inexpensive addition to the routine care of homosexual men with HIV infection.

Review: Mammary development in swine: effects of hormonal status, nutrition and management

Farmer, C. 2013. Review: Mammary development in swine: effects of hormonal status, nutrition and management. Can. J. Anim. Sci. 93: 1–7. There are three phases of rapid mammary accretion in swine, namely, from 90 d of age until puberty, during the last third of gestation and throughout lactation. Nutrition, endocrine status and management of gilts or sows during those periods can affect mammary development. More specifically, in growing gilts, feed restriction as of 90 d of age hinders mammary development and either supplying the phytoestrogen genistein or increasing circulating concentrations of prolactin stimulates mammogenesis. In late gestation, inhibition of relaxin or prolactin drastically diminishes mammary development and overly increasing dietary energy has a detrimental effect on mammogenesis. It also appears that feeding of the gestating sow can affect the mammary development of her offspring once it reaches puberty. Various management factors such as litter size, nursing intensity and use or non-use of a teat in the previous lactation will affect the amount of mammary tissue present at the end of lactation. Mammary development is followed by the essential process of involution whereby a rapid and drastic regression in parenchymal tissue takes place. It can occur either after weaning or in early lactation when teats are not being regularly suckled. Despite our current knowledge, much remains to be learned in order to develop the best management strategies for replacement gilts, and gestating and lactating sows that will maximize their milk production.

Demystifying moderators and mediators in intellectual and developmental disabilities research: a primer and review of the literature

BACKGROUND

Intellectual and developmental disability (IDD) researchers have been relatively slow to adopt the search for moderators and mediators, although these variables are key in understanding how and why relationships exist between variables. Although the traditional method of causal steps is useful for describing and understanding moderators and mediators, it is not sufficient for statistical analysis.

METHODS

The theoretical and statistical processes of evaluating moderators and mediators are explained in terms familiar to IDD psychologists, using examples from IDD literature. Moderator and mediator analyses in five leading IDD journals are assessed for patterns of usage.

RESULTS

Although the number of publications in the past decade exceeds previous years, the field is still behind others in both the quantity and quality of the use of moderators and mediators.

CONCLUSION

The field as a whole will advance if the recent theoretical and technical advances outlined in this paper are employed.

Impact of a long photoperiod during lactation on immune status of piglets

The effects of a long photoperiod treatment around parturition and throughout lactation on immune status of piglets were studied. Sows were assigned to 2 light regimens: i) standard short photoperiod (SP, n = 17), 8 h of daily light from d 112 of gestation until d 23 of lactation; and ii) long photoperiod (LP, n = 17), 23 h of daily light from d 112 of gestation to d 4 of lactation and 16 h thereafter. In front of the crates, under the side heat lamps and behind the sow, light intensities were 59 ± 5, 109 ± 6, and 44 ± 6 lx, respectively. On d 15 of lactation and at weaning (d 23), 2 piglets of similar BW per litter were selected and immunized intramuscularly with ovalbumin (OVA). Blood samples (5 mL serum and 10 mL whole blood) were taken at d 15 and d 23 of lactation, and at d 30, 37, and 44 of age after weaning to evaluate the antibody response to OVA and measure phagocytosis, lymphocyte proliferative response, and different circulating blood lymphocyte populations of piglets. Results showed that phagocytosis was increased in piglets submitted to LP (P < 0.05). A treatment × time interaction (P < 0.001) indicated that SP piglets developed a better IgG response to OVA than LP piglets. The percentage of B lymphocytes was also increased (P = 0.02) in SP piglets compared with piglets exposed to LP during lactation; the lymphocyte response to OVA tended to be enhanced (P = 0.07) over time in SP piglets. Different subpopulations of CD8+ lymphocytes were markedly increased in SP piglets at 23 d of age compared with piglets exposed to LP (treatment × time: P < 0.05). These results suggest that exposure of piglets to LP during lactation seems to reduce the capacity of piglets to develop a strong immune response to novel antigens. This may have important consequences on the ability of piglets to resist an infection after weaning.