Altering prolactin concentrations in sows

Productive and physiological implications of top-dress addition of branched-chain amino acids and arginine on lactating sows and offspring

BACKGROUND

Branched-chain amino acids (BCAAs), including L-leucine (L-Leu), L-isoleucine (L-Ile), L-valine (L-Val), and L-arginine (L-Arg), play a crucial role in mammary gland development, secretion of milk and regulation of the catabolic state and immune response of lactating sows. Furthermore, it has recently been suggested that free amino acids (AAs) can also act as microbial modulators. This study aimed at evaluating whether the supplementation of lactating sows with BCAAs (9, 4.5 and 9 g/d/sow of L-Val, L-Ile and L-Leu, respectively) and/or L-Arg (22.5 g/d/sow), above the estimated nutritional requirement, could influence the physiological and immunological parameters, microbial profile, colostrum and milk composition and performance of sows and their offspring.

RESULTS

At d 41, piglets born from the sows supplemented with the AAs were heavier (P = 0.03). The BCAAs increased glucose and prolactin (P < 0.05) in the sows' serum at d 27, tended to increase immunoglobulin A (IgA) and IgM in the colostrum (P = 0.06), increased the IgA (P = 0.004) in the milk at d 20 and tended to increase lymphocyte% in the sows' blood at d 27 (P = 0.07). Furthermore, the BCAAs tended to reduce the Chao1 and Shannon microbial indices (P < 0.10) in the sows' faeces. The BCAA group was discriminated by Prevotellaceae_UCG-004, Erysipelatoclostridiaceae UCG-004, the Rikenellaceae_RC9_gut_group and Treponema berlinense. Arginine reduced piglet mortality pre- (d 7, d 14) and post-weaning (d 41) (P < 0.05). Furthermore, Arg increased the IgM in the sow serum at d 10 (P = 0.05), glucose and prolactin (P < 0.05) in the sow serum at d 27 and the monocyte percentage in the piglet blood at d 27 (P = 0.025) and their jejunal expression of NFKB2 (P = 0.035) while it reduced the expression of GPX-2 (P = 0.024). The faecal microbiota of the sows in Arg group was discriminated by Bacteroidales. The combination of BCAAs and Arg tended to increase spermine at d 27 (P = 0.099), tended to increase the Igs (IgA and IgG, P < 0.10) at d 20 in the milk, favoured the faecal colonisation of Oscillospiraceae UCG-005 and improved piglet growth.

CONCLUSION

Feeding Arg and BCAAs above the estimated requirements for milk production may be a strategy to improve sow productive performance in terms of piglet average daily gain (ADG), immune competence and survivability via modulation of the metabolism, colostrum and milk compositions and intestinal microbiota of the sows. The synergistic effect between these AAs, noticeable by the increase of Igs and spermine in the milk and in the improvement of the performance of the piglets, deserves additional investigation.

Investigating risk factors behind piglet facial and sow teat lesions through a literature review and a survey on teeth reduction

Introduction

Piglet facial and sow teat lesions are the main reported reasons why pig producers routinely practice teeth resection. This is a painful procedure performed on piglets, where their needle teeth are clipped or ground to resect the pointed tip. The practice raises welfare concerns. In contrast to other procedures, such as tail docking, we know little about the risk factors for these two types of lesions.

Methods

We employed two methods to answer these questions: (1) reviewing the literature to identify potential risk factors, and (2) surveying pig production stakeholders worldwide to identify the occurrence of these lesions and the strategies used in practice that enable pig producers to manage or prevent these lesions while avoiding teeth resection. For the literature review, we used Google Scholar to include peer-reviewed publications and gray literature. We distributed the survey using convenience sampling and documented information on the current situation regarding teeth resection, including the methods, frequencies, and reasons for resecting piglets' teeth, the occurrence of piglet facial and sow teat lesions, and measures used to prevent and control these lesions.

Results

The literature review identified six major risk factors for both lesions, including the presence or absence of teeth resection, housing system, litter size, piglet management, environmental enrichment, milk production and other piglet management practices. However, most studies focused on the effects of the first two factors with very few studies investigating the other risk factors. There were 75 responses to the survey from 17 countries. The survey showed that half of the respondents practiced teeth resection with many recognizing that facial and teat lesions are the main reasons behind this practice. However, many producers used other interventions rather than teeth resection to prevent these lesions. These interventions focused on improving milk production of the sow, managing large litters, and providing environmental enrichment.

Discussion

More research is needed to validate these interventions and more science-based advice is needed to bridge the gap between research and practice to help more producers further understand the cause of piglet facial and sow teat lesions to transition toward the cessation of routine teeth resection.

Micelle silymarin supplementation to sows' diet from day 109 of gestation to entire lactation period enhances reproductive performance and affects serum hormones and metabolites

The aim of the present study was to explore the influences of varying doses of micelle silymarin (0%, 0.05%, 0.1%, and 0.2%) supplementation on sows' feed intake, milk yields, serum hormones, and litter growth using 40 multiparous sows (Landrace × Yorkshire, parity from 3 to 5) from the 109th prenatal day to the 21st postnatal day. Each treatment included 10 sows and each sow was used as an experimental unit. On weaning day, litter weight and litter weight gain were linearly improved (P < 0.01, both), corresponding to the increasing dose of silymarin micelle in the diet. Also, litter weight, litter weight gain, and average daily gain (ADG) of piglets born to treated sows exceeded (P < 0.05) those of offspring from the control sows (0% micelle silymarin). Feed intake in week 1, week 2, and the entire lactation period was increased (linear, P < 0.01) as micelle silymarin dose increased. Body weight (BW) loss of sows during lactation was linearly reduced (P = 0.003) with the increasing amounts of micelle silymarin. Average daily milk yields during lactation were also linearly increased (P = 0.002) in treated sows, exceeding (P = 0.046) that of control sows. Also, uniform increases were observed (P = 0.037) in fat content in milk produced by treated sows on day 14 of lactation. Epinephrine concentrations and aspartate aminotransferase (AST) activity in sow serum on day 21 postpartum were linearly declined (P = 0.010) as micelle silymarin dose increased, and were both declined (P < 0.05) in treated sows compared with the control. In addition, treated sows' serum had higher activity of superoxide dismutase (SOD) at parturition and glutathione peroxidase (GSH-Px), lower oxidized glutathione (GSSG) concentrations, and GSSG/GSH (glutathione) ratio (all, P < 0.01) on day 21 of lactation. Moreover, offspring from micelle silymarin-treated sows tended to (0.05 < P <0.1) have higher serum catalase (CAT) activity and total antioxidant capacity (T-AOC) concentrations. Taken together, the results showed that sows fed increasing levels of micelle silymarin from the 109th prenatal day to the 21st postnatal day had an incremental dose-dependent effect on higher feed intake, diminished BW loss, greater milk yields, and greater litter weight at weaning, and 0.2% of micelle silymarin could be optimal to achieve the better effect.

Providing domperidone throughout lactation enhances sow lactation performance

The goal of this project was to determine the effects of domperidone given throughout lactation on hormonal and metabolic status, lactational performance, and gene expression in mammary epithelial cells of sows. Second parity sows were divided in two treatment groups: 1) daily intramuscular injections with canola oil (Control, CTL, n = 24), or 2) daily intramuscular injections with 0.5 mg/kg body weight (BW) of domperidone (DOMP, n = 23). Injections were given at 08h05 starting the day after farrowing until weaning. Over the first 4 d of treatment, DOMP sows also received 0.5 mg/kg BW of domperidone per os twice daily, whereas CTL sows were fed the vehicle. Litter size was standardized to 11 ± 1 within 24 h of birth and piglets were weighed at birth, 24 h postpartum, and on days 7, 22 (weaning on day 23), 35, and 56. Sow feed intake was recorded daily. Representative milk samples were obtained aseptically on day 21 of lactation from 15 sows per treatment for compositional analyses and milk fat globules were used to measure mRNA abundances of various genes. Jugular blood samples were obtained from all sows on days 2, 8, 16, and 23 of lactation to measure concentrations of prolactin, insulin-like growth factor-1 (IGF-1), leptin, adiponectin, insulin, glucose, urea, and free fatty acids (FFA). Concentrations of prolactin (P < 0.001) and FFA (P < 0.01) were increased in DOMP compared with CTL sows, whereas concentrations of insulin were decreased (P < 0.05). Urea concentrations were increased by treatment (P < 0.05) on days 16 and 23 of lactation, and those of IGF-1 were increased (P < 0.01) on day 16. Piglets from DOMP sows were heavier than those from CTL sows on day 22 (P < 0.01). Milk composition was unaffected by treatment. The mRNA abundance in milk fat globules for casein beta and whey acidic protein were lower (P ≤ 0.05) in DOMP than CTL sows. The long form of the prolactin receptor and the signal transducer and activator of transcription 5A mRNA abundances tended to be lower (P < 0.10) in DOMP than CTL sows. In conclusion, hyperprolactinemia induced by domperidone during lactation affected the endocrine and metabolite status of sows and stimulated growth of their suckling piglets.

Effect of the Inclusion of Different Levels of Dietary Cactus (Opuntia ficus-indica) on Gilts' Biochemical Parameters and Feed Intake during Lactation

Simple Summary

The digestive and metabolic adaptations suffered by sows during the late gestation-lactation transition cause a decrease in the voluntary feed intake. These conditions favor a negative energy balance, forcing the body to mobilize body reserves to meet their nutritional requirements, which represents an obstacle to expressing their reproductive and productive potential. The supplementation of the sows’ diet with cactus (Opuntia ficus-indica L.) improves the feed intake in lactation due to the favorable modulation of biochemical indicators. However, the optimal addition of cactus to the diet of lactating sows is unknown. In the present study, the increase in the inclusion level of cactus did not linearly increase the feed intake in lactation. However, a linear increase in plasma insulin and osteocalcin concentrations were observed, which led to a decrease in the plasma glucose concentrations. We conclude that the inclusion level of cactus (fresh base) in the diet of lactating sows of 1.0% (with respect to the body weight of the sow) could improve the feed intake in lactation and reduce the loss of body weight of the sow at weaning.

Abstract

The regulation of sows’ metabolic state during the gestation-lactation transition is a requirement for a higher feed intake in lactation, an important aspect in improving animal welfare in current swine production systems. The present study aimed to evaluate the effects of the inclusion of different cactus (Opuntia ficus-indica L.) levels in the diet of gilts during late gestation and lactation on their biochemical parameters and voluntary feed intake during lactation. From day 85 of gestation until weaning, 40 gilts were divided into four groups: GNC (group with no cactus) with a basal diet (BD) only, G1C; group with 1% inclusion of cactus plus BD, G2C; group with 1.5% inclusion of cactus plus BD, and G3C; group with 2% inclusion of cactus plus BD. The dietary cactus supplementation increased the gilts’ feed intake (by 1.04 kg/day on average) during lactation and reduced their weight loss (4.3%) at weaning. The glucose concentrations were higher (range 73.0–83.9 mg/dL) in the GNC. The GNC had the highest triglyceride and cholesterol concentrations at day 100 of gestation. G3C had the highest osteocalcin concentration at day 100 of gestation. The highest feed intake and lowest glucose concentration were achieved with a cactus consumption of 1.04% in lactating gilts.

Effects of silymarin supplementation during transition and lactation on reproductive performance, milk composition and haematological parameters in sows

Silymarin has been shown to be a multiple-functional plant extract having antioxidant, hepatoprotective, hypolipidemic, antihypertensive, antidiabetic and anti-obesity effects. In recent years, the galactagogue effects of silymarin in animals and humans have also been revealed. This research was conducted to test whether dietary inclusion of silymarin during transition and lactation could impact reproductive performance of sows and to explore the underlying mechanisms. From day 108 of gestation to weaning, sows were randomly assigned to receive dietary treatment of silymarin (40 g/day) or not and were designated as control group (CGP, n = 55) or treatment group (TGP, n = 55). The results showed that piglets' average daily gain and average weaning weight were higher in TGP than CGP sows. In comparison with the CGP sows, the TGP sows had higher serum concentrations of catalase (CAT) on day 18 of lactation and glutathione peroxidase (GSH-Px) on day 7 of lactation. The TGP sows had lower concentration of TNF-α on day 7 of lactation and significantly lower concentration of IL-1β on day 18 of lactation than CGP sows. There was significantly higher serum concentration of PRL on day 7 of lactation in sows consuming silymarin than sows from the CGP group. On day 18 of lactation, the protein and urea contents in milk were significantly increased while the serum urea concentration was significantly decreased in TGP sows. In summary, our results indicate that silymarin supplementation during transition and lactation can increase circulating concentrations of PRL transiently, reduce oxidative stress, increase feed intake and enhance protein metabolism, thereby significantly increasing milk yield of sows and subsequently improving growth performance of their offsprings.

Effects of sustained hyperprolactinemia in late gestation on mammary development of gilts

The objective of this project was to determine the effects of sustained hyperprolactinemia for 7 or 20 d on mammary development in late-pregnant gilts. On day 90 of gestation, gilts were assigned to one of 3 groups to receive intramuscular (IM) injections of (1) canola oil (CTL, n = 18) until day 109 ± 1 of gestation; (2) a dopamine receptor antagonist, domperidone (0.5 mg/kg of body weight [BW]) until day 96 ± 1 of gestation (T7, n = 17); or (3) domperidone (0.5 mg/kg BW) until day 109 ± 1 of gestation (T20, n = 17). Domperidone-treated gilts also received 100 mg of domperidone per os twice daily from days 90 to 93 of gestation. Blood was sampled on days 89, 97, 104, and 110 for prolactin (PRL), insulin-like growth factor 1 (IGF1), lactose, urea, and glucose assays. Mammary glands were collected at necropsy, on day 110, for compositional and cell proliferation analyses. Abundance of mRNA for selected genes was also determined in the mammary gland and the pituitary gland. On day 97 of gestation, PRL concentrations were 3 times greater for T20 and T7 than CTL gilts and were also greater for T20 than T7 and CTL gilts on days 104 and 110 (P < 0.001). Concentrations of IGF1 in T20 and T7 gilts were elevated relative to controls on days 97 and 104 and were greater for T20 vs T7 and CTL gilts on day 110 (P < 0.05). There were no treatment effects (P > 0.1) on parenchymal or extraparenchymal tissue weights, or on epithelial proliferation as measured by immunohistochemistry for Ki-67. Treatments did not alter concentrations of dry matter (DM), fat, or DNA (P > 0.1) in parenchyma. Concentrations of RNA (P < 0.05) and protein (P < 0.10) as well as total parenchymal protein, RNA, and DNA (P < 0.05) were lower, or tended to be, in T20 than T7 or CTL gilts. Hyperprolactinemia for 20 d in late gestation increased mRNA abundance of the milk protein genes beta-casein (CSN2) and whey acidic protein (WAP) (P < 0.05) in mammary parenchyma and also decreased mRNA abundance of the long form of the prolactin receptor (PRLR-LF). Increasing PRL concentrations for 7 or 20 d in late gestation had no beneficial effects on the composition of the mammary gland, and sustained exposure to domperidone for 20 d reduced metabolic activity either by a lower expression of the long form of the PRL receptor in mammary parenchymal tissue or, most likely, by the early involution of parenchymal tissue. In conclusion, results do not support the hypothesis that a sustained hyperprolactinemia in late gestation could enhance mammary development of gilts.

The role of neurokinin A and its receptor in the regulation of prolactin secretion by the anterior pituitary of cyclic pigs

In pigs, plasma prolactin concentration markedly changes during the oestrous cycle and the regulation of its secretion is very complex. The contribution of neurokinins in this process has not been sufficiently delineated. The aim of the study was to examine the effects of neurokinin A (NKA) on prolactin synthesis and secretion in cyclic gilts. The expression of NKA precursor (Ppta) and receptor (Tacr2) genes as well as NKA and TACR proteins content in the porcine pituitaries (days 2-3, 9-10, 12-13, 15-16 and 19-20 of the cycle) was determined. Furthermore, the in vitro influence of NKA on the expression of prolactin (Prl), dopamine receptor (D2r), TRH receptor (Trhr) genes and prolactin secretion by the porcine pituitary cells (days 9-10, 15-16 and 19-20 of the cycle) was assessed. The expression of Ppta and Tacr2 as well as NKA and TACR proteins in the pituitary tissue has been changing throughout the oestrous cycle. NKA affected in vitro the expression of studied genes and prolactin secretion depending on the stage of the cycle, dose of NKA and/or duration of the cell incubation. Altogether, the study indicates that NKA is engaged in the modulation of prolactin secretion in the pig during the oestrous cycle.

Effect of the addition of cactus (O. ficus-indica) to the lactating sows' diet on piglet development at lactation and post-weaning

Objective:

The aim was to evaluate the effect of cactus (Opuntia ficus-indica) to the lactating sows’ diet on piglet development at lactation and post-weaning.

Materials and Methods:

Twenty-four litters of hybrids sows were evaluated in this study. The sows were divided into two groups: Control (CG), sows fed conventionally and experimental (EG), sows fed with commercial fed plus cactus. Post-weaning, the piglets of both groups were monitored up to the 20 kg liveweight (LW). It was evaluated, lactation (in sows): feed intake (FI), milk production (MP), and quality (MQ) and LW of the piglet. Post-weaning (in piglets): FI, LW, and length of intestinal villi (LIV) at 0, 24 h, and 42 days post-weaning.

Results:

FI sow^-1 was higher in EG (p < 0.05). MP, MQ, and LW piglet^-1 at weaning were equal (p > 0.05). FI piglet^-1 in the sixth and eighth week of age was higher in EG (p < 0.05); at the end of weaning phase, EG presented higher LW (p < 0.05): 8.4% more. LIV of the jejunum were higher (p < 0.05) in EG at 48 h (28.8%) and 42 days post-weaning (29.9%). At day 0, post-weaning LIV of the descending portion was higher (p < 0.05) in CG (1,571.0 μm) versus EG (1,058.0 μm). At day 42, post-weaning LIV of the transverse portion was higher (p < 0.05) in EG: 23.7% higher.

Conclusion:

Cactus intake in lactating sows does not affect the piglet development. However, post-weaning piglets present higher LIV in jejunum and transverse portion, aspect that improves LW.

GLUT1 and lactose synthetase are critical genes for lactose synthesis in lactating sows

Background

Lactose synthesis rate is an important factor in milk production and quality in mammals. Understanding the lactose synthesis mechanism is crucial for the improvement of milk quantity and quality. However, research on the temporal gene changes regarding lactose synthesis during the whole lactation is still limited. The objective of this study was to determine gene expression profiles related to lactose synthesis in sows during lactation, and further identify the critical steps or key factors in the lactose synthesis pathway.

Methods

To determine the temporal change of factors related to lactose synthesis in sows, milk from eight multiparous Yorkshire sows (parity 3 to 6) was collected at 0 h, 2 h, 6 h, 12 h, 24 h, day 2, 3, 4, 7, 14, and 21 after birth of the first piglet. Lactose content, prolactin and progesterone concentration, and gene or protein expression related to lactose synthesis were measured.

Results

The lactose yield increased gradually from D2 to D21 and reached a maximum at D14 (3-fold from D2) during lactation (P < 0.05). A similar trend was observed in IGF-1 and insulin concentrations in milk, both of which were greatest at D3 with a subsequent decrease during middle to late lactation. Conversely, milk prolactin and progesterone concentrations moderately decreased with the progression of lactation. The mRNA or protein expressions related to glucose transportation (GLUT1), glucose-galactose interconversion (HK1 and UGP2), UDP-galactose transportation (SLC35A2), and lactose synthetase (LALBA and B4GALT1) in the lactose synthesis pathway were significantly upregulated during early to middle lactation and plateaued by late lactation (P < 0.05).

Conclusions

These novel findings suggest that the increased lactose synthesis in lactation was related to the coordinated upregulation of genes or enzymes in the lactose synthesis pathway, and glucose transportation (GLUT1) and lactose synthetase (LALBA and B4GALT1) might be the critical steps in the lactose synthesis pathway of sows during lactation.