Hyperprolactinemia using domperidone in prepubertal gilts: Effects on hormonal status, mammary development and mammary and pituitary gene expression

Objectives of this experiment were to determine if the domperidone protocol previously used for gestating gilts can also lead to hyperprolactinemia in growing gilts, and to assess the effects of such a protocol on hormonal status, mammary development and gene expression in mammary and pituitary tissue of gilts at puberty. The impact on future lactation performance was also determined. At 75 ± 3 kg body weight (BW), gilts were divided between: 1) controls (CTL), receiving daily intramuscular (IM) injections of canola oil (1.1 mL) for 29 d (n = 41), and 2) treated (DOMP), receiving daily IM injections with 0.5 mg/kg BW of the dopamine receptor antagonist domperidone for 29 d (n = 40). In addition to that daily injection, treated gilts also received twice daily IM injections with 0.5 mg/kg BW of domperidone over the first 3 d of treatment. Fifteen gilts per treatment were sacrificed at 210 ± 5 d of age to collect mammary glands (for compositional analysis and gene expression) and the anterior pituitary (for gene expression). Remaining gilts were bred and allowed to farrow. Blood was sampled at the onset of treatment and on days 14 and 30. Gilts that farrowed were also blood sampled on days 3 and 20 of lactation. Blood was assayed for prolactin (PRL), leptin, insulin-like growth factor 1 (IGF-1), urea, free fatty acids and glucose. Concentrations of PRL increased after 14 d and 30 d of treatment (P < 0.01) and were lesser on day 3 of lactation in DOMP than CTL gilts (P < 0.01). At puberty, there were tendencies (P < 0.10) for total parenchymal protein and DNA to be greater in DOMP than CTL gilts. Treatment did not affect mRNA abundance of PRL or the long form of the PRL receptor genes in the pituitary gland at puberty but expression level of the dopamine receptor D2 and PRL genes was much lower in pubertal than late-pregnant gilts (P < 0.001). Furthermore, many genes related with PRL had a much greater expression level in late pregnancy than at puberty. On day 20 of lactation, CTL sows had greater concentrations of urea than DOMP sows (P < 0.01). The growth rate of litters was not affected by treatment nor was milk composition (P > 0.10). Even though PRL concentrations were increased with treatment, the absence of effect on mammary development was either due to timing relative to developmental stage, whereby treatment was initiated when gilts were too young, or was because all PRL receptors may have been saturated thereby preventing biological action of additional PRL.

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.

Milk yield, milk composition, and hepatic lipid metabolism in transition dairy cows fed flaxseed or linola

The response of transition dairy cows to dietary supplementation with fat sources of various fatty acid profiles could affect hepatic fat metabolism differently. Twenty-eight Holstein cows were blocked for similar calving date 4wk before expected parturition to compare the effects of feeding sources of n-3 and n-6 fatty acids on milk production and composition, plasma metabolites, and liver parameters. Cows within each block were assigned to 1 of 3 isonitrogenous and isoenergetic diets: control with a source of calcium salts of palm oil (MEG; 1.1 and 2.6% of the dry matter in prepartum and postpartum diets, respectively); n-3 fatty acids supplied as whole flaxseed (WFL; 4.8 and 7.7% of the dry matter in prepartum and postpartum diets, respectively); and n-6 fatty acids supplied as whole linola (WLO; 4.8 and 7.7% of the dry matter in prepartum and postpartum diets, respectively). Diets were fed until wk 14 of lactation. Contrasts of WFL versus WLO and polyunsaturated fatty acids versus MEG were compared. Cows fed polyunsaturated fatty acids increased dry matter intake over time at a greater extent than those fed MEG, which resulted in enhanced energy balance. Cows fed MEG produced more milk compared with those fed polyunsaturated fatty acids, and there was no difference between those fed WFL and WLO. We found no effect on body condition score and body weight. Plasma concentrations of glucose, fatty acids, and BHB were similar among diets. There was no effect of diet on concentration of glycogen and activities of superoxide dismutase and glutathione peroxidase in the liver. We observed higher concentrations of hepatic lipids and triacylglycerol in cows fed MEG compared with those fed polyunsaturated fatty acids, and no difference between WFL and WLO. Hepatic catalase activity tended to be higher on wk 4 after calving for cows supplemented with WFL compared with those fed WLO. Feeding linoleic and linolenic acids as unprotected oilseeds increased dry matter intake over time at a greater extent for cows fed MEG, improved the energy status, and lowered hepatic lipids and triacylglycerol contents, which may contribute to enhance the health status of transition dairy cows.

Effects of leptin and adiponectin on the growth of porcine myoblasts are associated with changes in p44/42 MAPK signaling

We hypothesized that both adiponectin and leptin affect the growth of porcine skeletal muscle cells, with fatty acids acting as modifiers in adipokine action and that both adipokines influence the gene expression of their receptors. Therefore, the objective of this study was to investigate the effects of recombinant adiponectin and leptin on cell number (DNA) and DNA synthesis rate with and without oleic acid supplementation, on cell death, and on key intracellular signaling molecules of proliferating porcine myoblasts in vitro. Moreover, the mRNA expression of genes encoding for the leptin and adiponectin receptors (LEPR, ADIPOR1, ADIPOR2) as affected by leptin or adiponectin was examined. Recombinant porcine adiponectin (40 μg/mL) and leptin (20 ng/mL) increased DNA synthesis rate, measured as [(3)H]-thymidine incorporation (P < 0.01), reduced cell viability in terms of lactate dehydrogenase release (P < 0.05), or lowered DNA content after 24 h (P < 0.05). In adiponectin-treated cultures, oleic acid supplementation increased DNA synthesis rate and reduced cell number in a dose-dependent manner (P < 0.05). Both adiponectin (P = 0.07) and leptin (P < 0.05) induced a transient activation of p44/42 mitogen-activated protein kinase (MAPK) after 15 min, followed by decreases after 60 and 180 min (P < 0.05). Adiponectin tended to increase c-fos activation (P = 0.08) and decreased p53 activation at 180 min (P = 0.03). Both adiponectin and leptin down-regulated the abundance of ADIPOR2 mRNA and, transiently, of LEPR mRNA (P < 0.05). In conclusion, adiponectin and leptin may adversely affect the growth of porcine myoblasts, which is related to p44/42 MAPK signaling and associated with changes in ligand receptor gene expression.

Impact of diet deprivation and subsequent over-allowance during prepuberty. Part 1. Effects on growth performance, metabolite status, and mammary gland development in gilts

The impact of diet deprivation and subsequent over-allowance on the metabolite status, mammary development, and mammary gene expression in prepubertal gilts was determined. Forty-seven gilts were reared under a conventional (control, CTL; n = 23) or an experimental (treatment, TRT; n = 24) dietary regimen. The later regimen (consisting of diet deprivation and subsequent over-allowance) provided 70 (restriction diet, RES) and 115% (over-allowance diet, OVER) of the protein and DE contents provided by the CTL diet. Experimental diets were fed ad libitum starting at 27.7 ± 3.4 kg of BW as follows: 3 wk RES, 3 wk OVER, 4 wk RES, and 4 wk OVER. At each diet change, BW and individual feed intakes were measured, and blood samples for metabolite and IGF-I assays were obtained. Some gilts (11 CTL and 12 TRT) were slaughtered on d 235 (after reaching puberty) to collect mammary tissue for compositional analyses and measures of gene expression. Body weight gain (P < 0.01) and G:F (P < 0.05) of gilts were reduced during each period with the RES diet; however, there was no compensatory growth during the periods when the OVER diet was fed. Feeding the RES diet reduced concentrations of urea and IGF-I (P < 0.01) and feeding the OVER diet increased FFA (P < 0.01) and glucose (P < 0.10) in TRT gilts compared with CTL gilts. The TRT gilts had less parenchymal tissue (P < 0.05) and tended to have less total parenchymal fat and protein (P < 0.10) than CTL gilts. The mammary mRNA relative abundance of the signal transducers and activators of transduction 5B was decreased in TRT compared with CTL gilts (P < 0.05). In conclusion, the diet deprivation and over-allowance regimen used in the growing-finishing period did not have beneficial effects on mammary development after puberty. In fact, a detrimental effect was observed.

Relationships between backfat thickness and reproductive efficiency of sows: A two-year trial involving two commercial herds fixing backfat thickness at breeding

In this study, we established whether controlling backfat thickness at breeding over a long time period can result in optimized reproductive performance in sows. Two commercial herds were used: herd A (322 purebred Landrace sows) and herd B (337 cross-bred Yorkshire-Landrace sows). Backfat thickness at breeding and farrowing, along with reproductive data [live Born (LB), stillborn, mummified, piglets alive at 48 h (LB48) and the weaning-to-estrus interval (WEI)] were collected over nine parities. The herd B producer was more successful in maintaining a steady backfat thickness at breeding than was the herd A producer. At breeding, the backfat thickness of sows from herd A showed a marked decrease between parities 2 and 5. During their first parity, these sows gained the least backfat during gestation and lost the most backfat during lactation. Sows from herd B had more LB and LB48 than sows from herd A. In herd A, a longer WEI was found in first and second parity sows. Our results demonstrate that maintaining backfat thickness throughout the reproductive cycle is more important than fixing this parameter at breeding alone. This is particularly true for gilts, which are prone to mobilize fat tissue reserves, a condition associated with declining reproductive performance. Key words: Backfat thickness, reproductive performance, sow, weaning-to-estrus interval

Effects of supplements of folic acid, vitamin B12, and rumen-protected methionine on whole body metabolism of methionine and glucose in lactating dairy cows

The present experiment was undertaken to determine the effects of dietary supplements of rumen-protected methionine and intramuscular injections of folic acid and vitamin B(12), given 3 wk before to 16 wk after calving, on glucose and methionine metabolism of lactating dairy cows. Twenty-four multiparous Holstein cows were assigned to 6 blocks of 4 cows each according to their previous milk production. Within each block, 2 cows were fed a diet estimated to supply methionine as 1.83% metabolizable protein, equivalent to 76% of methionine requirement, whereas the 2 other cows were fed the same diet supplemented daily with 18 g of rumen-protected methionine. Within each diet, the cows were administrated either no vitamin supplement or weekly intramuscular injections of 160 mg of folic acid plus 10 mg of vitamin B(12.) To investigate metabolic changes at 12 wk of lactation, glucose and methionine kinetics were measured by isotope dilution using infusions of 3[U-(13)C]glucose, [(13)C]NaHCO(3) and 3[1-(13)C,(2)H(3)] methionine. Milk and plasma concentrations of folic acid and vitamin B(12) increased with vitamin injections. Supplementary B-vitamins increased milk production from 34.7 to 38.9 +/- 1.0 kg/d and increased milk lactose, protein, and total solids yields. Whole-body glucose flux tended to increase with vitamin supplementation with a similar quantitative magnitude as the milk lactose yield increase. Vitamin supplementation increased methionine utilization for protein synthesis through increased protein turnover when methionine was deficient and through decreased methionine oxidation when rumen-protected methionine was fed. Vitamin supplementation decreased plasma concentrations of homocysteine independently of rumen-protected methionine feeding, although no effect of vitamin supplementation was measured on methionine remethylation, but this could be due to the limitation of the technique used. Therefore, the effects of these B-vitamins on lactation performance were not mainly explained by methionine economy because of a more efficient methylneogenesis but were rather related to increased glucose availability and changes in methionine metabolism.

Feeding flaxseed to sows during late-gestation and lactation affects mammary development but not mammary expression of selected genes in their offspring

Mammary gland composition and mammary gene expression were measured in pubertal gilts whose dam were fed a control (CTL) diet or a diet with a 10% supplement of flaxseed (FS) during late-gestation and throughout lactation. Parenchymal weight expressed as a percentage of body weight tended to be greater in offspring from FS compared with CTL sows (P < 0.1) and to contain less fat (P < 0.1). Offspring from FS sows had more parenchymal protein, whether expressed as a percentage (P < 0.05) or total amount in tissue (P ≤ 0.05), than offspring from CTL sows. No changes (P > 0.1) in mammary gland expression of the studied genes were observed with dietary treatment. Key words: Flaxseed, gene expression, gestation, mammary development, offspring, porcine

Characterization of swine adiponectin and adiponectin receptor polymorphisms and their association with reproductive traits

In this study, polymorphisms in genes encoding porcine adiponectin (ADIPOQ) and its receptors (ADIPOR1 and ADIPOR2) were evaluated for associations with reproductive traits in a Landrace sow population. Sixteen SNPs were identified, and among these, associations were found between reproductive traits and five SNPs. Heterozygous multiparous females for SNP ADIPOQEF601160:c.178G>A had fewer stillborn piglets (P < 0.05) and shorter weaning-to-oestrus intervals (P < 0.05). Multiparous females bearing the mutant allele for SNP ADIPOQEF601160:c.*1094_1095insC gave birth to fewer stillborn piglets (P < 0.05). In addition, selection for the ADIPOQ [A;C] haplotype is expected to result in multiparous sows having the lowest number of stillborn piglets and shorter weaning-to-oestrus intervals. In second-parity sows, the polymorphism in ADIPOR1 (AY856513:c.*129A>C) showed significant associations with live-born (P < 0.01) and stillborn (P < 0.05) piglets. In multiparous sows, a significant association was observed for an ADIPOR2 polymorphism (AY856514:c.*112G>A), with the c.*112GA genotype associated with shorter weaning-to-oestrus intervals (P < 0.01). Haplotype analyses of ADIPOR2 SNPs revealed that selection in favour of the [A;C] haplotype and against the [G;G] haplotype may result in sows having an increased number of live-born piglets and shorter weaning-to-oestrus intervals. We have therefore described specific SNPs and haplotypes that are associated with large litter size, fewer stillborn and mummified piglets and shorter weaning-to-oestrus intervals. Selection for these SNPs and haplotypes is a strategy to improve reproductive success in pigs.

Evaluation of molecular methods used for establishing the interactions and functions of microorganisms in anaerobic bioreactors

Molecular techniques have unveiled the complexity of the microbial consortium in anaerobic bioreactors and revealed the presence of several uncultivated species. This paper presents a review of the panoply of classical and recent molecular approaches and multivariate analyses that have been, or might be used to establish the interactions and functions of these anaerobic microorganisms. Most of the molecular approaches used so far are based on the analysis of small subunit ribosomal RNA but recent studies also use quantification of functional gene expressions. There are now several studies that have developed quantitative real-time PCR assays to investigate methanogens. With a view to improving the stability and performance of bioreactors, monitoring with molecular methods is also discussed. Advances in metagenomics and proteomics will lead to the development of promising lab-on chip technologies for cost-effective monitoring.

Influence of genotype on metabolic variables, colostrum and milk composition of primiparous sows

Composition of colostrum and milk in first-parity sows from four genetic lines, namely, synthetic Belgian Landrace/Pietrain (B), Duroc (D), Landrace (L) and Yorkshire (Y) were determined. Circulating concentrations of leptin, IGF-I, glucose and FFA were also measured in sows. Differences in colostrum and milk composition were observed between genotypes, but did not generally seem related to variables in blood. Colostrum and day-2 milk from D sows contained more protein (P < 0.05) and less lactose (P < 0.1) than that from sows of other genotypes. Results suggest that selection strategies to improve the composition of milk and colostrum of sows from European breeds could be a useful tool to increase their lactation potential. Key words: Colostrum, lactation, milk composition, sow

Hepatic Lipid Metabolism in Transition Dairy Cows Fed Flaxseed

Thirty-three Holstein cows averaging 687 kg of body weight were allotted 6 wk before the expected date of parturition to 11 groups of 3 cows blocked within parity for similar calving dates to determine the effects of feeding different sources of fatty acids on blood parameters related to fatty liver and profile of fatty acids in plasma and liver. Cows were fed lipid supplements from 6 wk before the expected date of parturition until d 28 of lactation. Cows within each block were assigned to 1 of 3 isonitrogenous and isoenergetic dietary supplements: control with no added lipids (CO); unsaturated lipids supplied as whole flaxseed (FL; 3.3 and 11.0% of the dry matter in prepartum and postpartum diets, respectively); and saturated lipids supplied as Energy Booster (EB; 1.7 and 3.5% of the DM in prepartum and postpartum diets, respectively). Diets EB and FL had similar ether extract concentrations. Multiparous cows fed EB had lower dry matter intake and milk production, higher concentrations of nonesterified fatty acids and beta-hydroxybutyrate in plasma and triglycerides (TG) and total lipids in liver, and lower concentrations of plasma glucose and liver glycogen than those fed FL and CO. Production of 4% fat-corrected milk was similar among treatments. Multiparous cows fed FL had the highest liver concentrations of glycogen on wk 2 and 4 after calving and lowest concentrations of TG on wk 4 after calving. Liver C16:0 relative percentages in multiparous cows increased after calving whereas those of C18:0 decreased. Relative percentages of liver C16:0 were higher in wk 2 and 4 postpartum for multiparous cows fed EB compared with those fed CO and FL; those of C18:0 were lower in wk 4 postpartum for cows fed EB compared with those fed CO and FL. Liver C18:1 relative percentages of multiparous cows increased after calving and were higher in wk 4 for cows fed EB compared with those fed CO and FL. The inverse was observed for liver C18:2 relative percentages. In general, diets had more significant effects on plasma concentrations of nonesterified fatty acids, beta-hydroxybutyrate, and glucose and liver profiles of fatty acids, TG, total lipids, and glycogen of multiparous than primiparous cows. These data suggest that feeding a source of saturated fatty acids increased the risk of fatty liver in the transition cow compared with feeding no lipids or whole flaxseed. Feeding flaxseed compared with no lipids or a source of saturated fatty acids from 6 wk before calving could be a useful strategy to increase liver concentrations of glycogen and decrease liver concentrations of TG after calving, which may prevent the development of fatty liver in the transition dairy cow.

Effects of flaxseed supplementation on endometrial expression of ISG17 and intrauterine prostaglandin concentrations in primiparous dairy cows submitted to GnRH-based synchronized ovulation

The objective of the experiment was to determine the effects of feeding whole flaxseed on ovarian function and uterine concentration of prostaglandins on the 17th day post-ovulation. Fortyeight primiparous Holstein cows averaging 550 kg of body weight (BW) were allotted at 2 wk postpartum to two groups of 24 animals: a control diet with no added fat (CON) or a diet with 9% whole flaxseed (FLA). At 6 wk postpartum cows were subjected to a Presynch-Ovsynch protocol with and without artificial insemination on day 0. Real-time transrectal ultrasonography and plasma progesterone concentrations were used to evaluate ovarian function. On day 17, uterine flushings and biopsies of uterine endometrium were collected. Synchronized ovulation rates based on low and high plasma progesterone concentrations on days 0 and 7, respectively, were the same for cows fed CON and those fed FLA (87.5 vs. 87.5%). The 13,14-dihydro-15-keto-PGF2α (PGFM) to prostaglandin E metabolite (PGEM) ratio in uterine flush was significantly higher for non-inseminated cows fed CON (32.0) than for non-inseminated cows fed FLA (17.5) and there was no difference between pregnant cows fed CON (12.2) and those fed FLA (12.0). Feeding flaxseed before breeding may contribute to increased fertility by improving uterine conditions for embryo survival. Key words: Flaxseed, dairy cattle, ovarian function, prostaglandins

Expression of adiponectin and its receptors in swine1,2

Adiponectin is an adipocyte-derived hormone that plays an important role in lipid metabolism and glucose homeostasis. Objectives of this study were 1) to determine the presence and distribution of adiponectin and its receptors 1 and 2 (adipoR1 and adipoR2) in porcine tissues; 2) to characterize pig adiponectin, adipoR1, and adipoR2 mRNA levels in various fat depots from three different breeds of pigs; and 3) to study, in stromal-vascular cell culture, the effects of leptin and tumor necrosis factor-alpha (TNFalpha) on pig adiponectin, adipoR1, and adipoR2 gene expression. To this end, fat Chinese Upton Meishan (UM, n = 10), lean Ham Line (HL, n = 10), and Large White (LW, n = 10) gilts were used. We report the isolation of partial cDNA sequences of pig adipoR1 and adipoR2. Porcine-deduced AA sequences share 97 to 100% homology with human and murine sequences. Pig adipoR1 mRNA is abundant in skeletal muscle, visceral fat, and s.c. fat tissues, whereas adipoR2 mRNA is predominantly expressed in liver, heart, skeletal muscle, and visceral and s.c. fat tissues. Pig adiponectin mRNA levels in s.c. and visceral fat tissues were not associated with plasma insulin and glucose in fasting animals. Subcutaneous (r = -0.44, P < 0.05), visceral (r = -0.43, P < 0.05), and total body fat (r = -0.42, P < 0.05) weights were negatively correlated with adiponectin mRNA levels measured in visceral, but not s.c., fat. Pig adipoR1 and adipoR2 mRNA levels, in visceral fat, were less expressed in fat UM gilts than in the lean HL gilts (P < 0.05). Inverse associations were found between s.c. (r = -0.57, P < 0.01), visceral (r = -0.46, P < 0.05), and total body fat (r = -0.56, P < 0.01) weights and adipoR2 mRNA levels in visceral fat only. We were unable to find such associations for adipoR1 mRNA levels in the overall gilt population. The current study demonstrated that TNFalpha downregulates adiponectin and adipoR2, but not adi-poR1, mRNA levels in stromal-vascular cell culture. Moreover, leptin significantly decreased adiponectin mRNA levels, whereas there was no effect on adiponectin receptors. We conclude that adiponectin and adi-poR2 mRNA levels, but not adipoR1, are modulated in pig visceral fat tissues. Furthermore, our results indicate that TNFalpha interferes with adiponectin function by downregulation of adipoR2 but not of adipoR1 mRNA levels in pigs.

Gene expression of leptin, leptin receptor, prolactin receptor and whey acidic protein in mammary glands of late-pregnant gilts from two breeds

In order to identify genes which are essential for pig mammary gland development, mRNA levels of prolactin receptor (PRL-R), leptin, leptin receptor and whey acidic protein (WAP) were measured in parenchymal tissue of 110-d-pregnant gilts. Thirteen Upton-Meishan (UM) and 14 Large White (LW) pregnant gilts and 5 non-pregnant control gilts (2 LW and 3UM) were used. PRL-R and WAP mRNA levels were higher in pregnant than in non-pregnant gilts (P < 0.05). Leptin mRNA levels were higher in UM than in LW gilts (P < 0.05), but this breed effect was not seen when leptin mRNA levels were corrected for percent fat in parenchyma. Correlations were found between concentrations of IGF-I in plasma and PRL-R (P < 0.01) and WAP (P < 0.05) mRNA levels in UM gilts. Serum prolactin (PRL) was correlated with leptin mRNA levels in the overall (P < 0.05) and LW (P < 0.05) populations of gilts, while estradiol was associated with leptin receptor mRNA in UM gilts (P < 0.05). The mRNA levels of all studied genes were positively correlated with mammary parenchymal and extra parenchymal weights in UM gilts, whereas these variables were only correlated with PRL-R and WAP gene expression in LW gilts. The presence of leptin and leptin receptor mRNA in parenchymal tissue suggests a paracrine role for leptin in mammary tissue of late-pregnant gilts. These results also suggest that the PRL signalling pathway is fully active at the transcriptional level in the mammary gland of gilts at 110 d of pregnancy. Key words: Genetics, pig, mammary glands, Meishan, mRNA

Endocrinology and mammary development of lactating Genex-Meishan and Large White sows

Endocrine and metabolic data as well as mammary tissue composition were obtained in Genex-Meishan (GM, containing 50% Chinese Meishan genes) and Large White (LW) lactating sows. Jugular vein cannulae were used to collect serial blood samples from 9 LW and 8 GM sows for 4 h every 15 min on days 6 and 19 of lactation. Concentrations of prolactin and cortisol were determined on all samples while those of insulin-like growth factor-I (IGFI), growth hormone (GH), glucose and free fatty acids (FFA) were measured in hourly samples. Milk samples were obtained from 19 GM and 16 LWsows on day 23 of lactation and all sows were slaughtered on day 25. Mammary glands were excised and analyzed for tissue composition and for number and affinity of prolactin receptors. Concentrations of plasma IGF-I were lower (P < 0.01) and plasma FFA greater (P < 0.001) in GM than in LW sows. On day 6 of lactation, serum prolactin (P < 0.05) and cortisol (P < 0.01) concentrations were greater and glucose values lower (P < 0.001) in GM than in LW sows. The concentration of IGFI in lactoserum was lower (P < 0.001) while that of prolactin was greater (P < 0.05) in GM compared to LW sows on day 23 of lactation. There was less (P < 0.001) residual milk and more (P < 0.05) parenchymal RNA in mammary glands from GM compared to LW sows. The affinity of prolactin receptors was also greater (P < 0.05) in GM than in LW sows. The better emptying of mammary glands by litters from GM sows and the greater circulating concentrations of prolactin in early lactation as well as the greater affinity of mammary prolactin receptors may be related to the great milking potential of Meishan-derived sows. Key words: Hormones, lactation, mammary gland, Meishan, prolactin, sows

Uterine immune reaction and reproductive performance of sows inseminated with extended semen and infused with pooled whole dead semen1,2,3

The objective of this study was to investigate the effect of infusing whole dead semen (WDS) after AI with diluted commercial semen on uterine inflammatory reaction and embryonic survival rate in gilts. Sixty Yorkshire-Landrace gilts were assigned at their second estrus to one of the following AI treatments: 1) commercial semen adjusted to 1 x 10(9) sperm cells (S1) per dose, followed by an infusion of 80 mL of WDS (S1-WDS); 2) S1 followed by an infusion of 80 mL of Beltsville Thawing Solution (S1-BTS); 3) commercial semen adjusted to 3 x 10(9) sperm cells (S3) per dose, followed by an infusion of 80 mL of BTS (S3-BTS); and 4) a negative control group, in which gilts received two infusions of 80 mL of BTS (BTS). Two days after the first AI, eight gilts from Groups 1, 2, and 4 were slaughtered and reproductive tracts were collected. One horn was cut open longitudinally along the antimesometrial aspect and endometrial samples were taken and immediately frozen for analysis of messenger RNA (mRNA) abundance for inflammatory cytokines and growth factors. The other horn was flushed with 20 mL of PBS, and the contents of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) were determined by ELISA. On d 25 after AI, gilts from Groups 1, 2, and 3 were slaughtered and their reproductive tracts were collected to evaluate the number of fetuses and corpora lutea. On d 2 after the first AI, only TGF-beta1 was detected in the flush of all gilts, and no difference was observed between S1-WDS, S1-BTS, and BTS gilts. Endometrial levels of IFN-gamma and interleukin (IL)-6 mRNA were marked in all gilts, but they were not affected by the AI treatments, whereas the mRNA abundances for IL-1 and IL-2 were negligible. Infusions of WDS or BTS after a fertile AI did not affect IGF-I, IGF-I receptor, or IGF-II mRNA levels compared with gilts infused with BTS only, whereas the mRNA abundance for the IGF-II receptor was decreased (P < 0.05) in WDS-infused gilts. In gilts inseminated with S1 doses, infusion of WDS did not affect the number of live embryos. Although infusions of WDS did not affect the mRNA level and secretion of the cytokines measured and did not improve embryonic survival rates, further studies are needed to better understand the influence of semen composition on the uterine response after mating.

Expression levels of STAT5A and STAT5B in mammary parenchymal tissue from Upton-Meishan and Large White gilts

The implication of STAT5A and STAT5B in mammary gland development and maintenance of lactation is well documented in rodents and humans. However, little is known regarding their roles in mammary gland development during gestation in pigs. We identified and analyzed the complete coding sequences of swine STAT5A and STAT5B and evaluated their mRNA levels in mammary glands of gestating gilts (day 110) in two different breeds, Upton-Meishan and Large White. Sequence analysis revealed a new APASA insertion in the STAT5A amino acid sequence that is in close proximity to residue Tyr 699 and whose phosporylation leads to the activation of target genes’ transcription. STAT5A mRNA levels were higher in Upton-Meishan than in Large White. In both breeds, STAT5B mRNA levels were higher than those of STAT5A , which is contrary to what was found in other mammals. A correlation between circulating IGF-I levels and STAT5B mRNA levels in the mammary gland was noticed in the Upton-Meishan breed only. STAT5B mRNA levels in mammary tissue of Large White gilts were highly correlated with extra-parenchymal tissue weight, parenchymal tissue weight, total parenchymal DNA, RNA and RNA/DNA ratio. In Upton-Meishan gilts, correlations were observed only between extra-parenchymal weight and STAT5A and STAT5B mRNA levels. These results indicate that there are significant differences in mRNA levels of STAT5A and STAT5B in the mammary glands of pregnant gilts when compared to other mammals, and between swine breeds. Key words: Mammary glands, signal transducers, pregnancy, kinases, pig, expression

Effect of folic acid and glycine supplementation on embryo development and folate metabolism during early pregnancy in pigs

The present work aimed to determine if different levels of prolificacy either by parity or by genetic origin are linked to folate metabolism. Nulliparous Yorkshire-Landrace (YL) and multiparous YL, and multiparous Meishan-Landrace (ML) sows were randomly assigned to two treatments: 0 ppm or 15 ppm folic acid+0.6% glycine. Supplements were given from the estrus before mating until slaughter on d 25 of gestation. At slaughter, embryo and endometrial tissues were collected to determine concentrations of DNA, protein, and homocysteine. Allantoic fluid samples were also collected to determine concentrations of folates, vitamin B12 and amino acids. Blood samples were taken at first estrus, at mating, and on d 8, 16, and 25 of gestation to determine serum concentrations of folates, vitamin B12, and relative total folate binding capacity (TFBC). Over the entire experiment, multiparous YL sows had higher average serum concentrations of folates than nulliparous YL sows (P < 0.05) but had similar serum concentrations of relative TFBC. Concentrations of folates and relative TFBC averaged higher in ML measured over the entire experiment than in multiparous YL sows (P < 0.05). Concentrations of serum vitamin B12 were higher in multiparous YL than in ML sows or YL nulliparous sows (P < 0.05) over the entire experiment. In allantoic fluid, folates, vitamin B12, and essential amino acids contents were significantly lower in ML than in YL multiparous sows (P < 0.05). The folic acid+glycine supplement increased concentrations of serum folates, but the increase was more marked in nulliparous YL sows (nulliparous x folic acid+glycine, P < 0.05). The folic acid+glycine supplement had no effect on litter size and embryo survival, but it tended to increase embryo DNA in multiparous YL sows (P = 0.06) but not in ML and nulliparous YL sows. Homocysteine was decreased by folic acid+glycine supplement in embryos from all sows, but in endometrium, the folic acid+glycine effect was dependent on parity (nulliparous x folic acid+glycine, P < 0.05). The effects of folic acid+glycine on litter size and embryo development and survival and some aspects of folate metabolism suggest that the basal dietary content of folic acid+glycine was adequate for ML and nulliparous YL sows but not to optimize embryo development in YL multiparous sows.

Lactational performance, nursing and maternal behavior of Upton-Meishan and Large White sows

The growth of litters from 19 Upton-Meishan (UM) and 16 Large White (LW) sows was recorded from birth to weaning (25 d of age). Water and feed intake of sows were recorded. Suckling behavior was studied on days 5 and 20 of lactation. Milk yield was measured on day 22 and a milk sample was obtained the next day. Water intakes were similar (P = 0.947) for both breeds, yet UM sows consumed less feed throughout lactation (P = 0.0002). Average piglet (P < 0.05) and total litter (P < 0.001) weights were greater as of day 7 in UM compared to LW sows. Mean piglet weight on day 24 was 6.13 ± 0.16 kg for UM litters and 5.33 ± 0.33 kg for LW litters. Suckling interval was similar for UM and LW litters on day 5 (P = 0.533), but was shorter for UM litters on day 20 (41.4 ± 1.2 vs. 48.3 ± 2.8 min; P= 0.060). On day 22, daily milk yield corrected for actual suckling interval was greater (10.59 ± 0.47 vs. 8.03 ± 0.65 kg; P = 0.003) in UM sows. Milk from UM sows contained more fat (P= 0.042) and lactose (P = 0.005). In conclusion, the greater growth rate of piglets from UM sows is mainly due to a higher frequency of nursings and to greater energy content of milk. Key words: Sows, lactation, breed, Meishan, behavior, nursing

Effects of breed, parity, and folic acid supplement on the expression of leptin and its receptors' genes in embryonic and endometrial tissues from pigs at day 25 of gestation

Recent evidence has pointed toward a possible role of leptin (Lep) and its receptor (Lepr) in early gestation materno-fetal cross-talk. However, in gestating sows, exhaustive characterization of leptin mRNA expression in backfat and leptin-receptor mRNA expression in endometrial and embryonic tissues is still pending. The objectives of this study were to characterize the Lep, Lepr, and long Lepr-L isoform mRNA expression according to the breed and parity of gestating sows or to specific folic acid (B(9)) + glycine dietary treatments. To this end, nulliparous (GT) and multiparous occidental Yorkshire-Landrace (YL) sows as well as multiparous Chinese Meishan-Landrace (ML) sows were used. These sows were randomly assigned to two different dietary treatments: 0 or 15 ppm of B(9) + 0.6% glycine, given from the estrous preceding mating until slaughter on Day 25 of gestation. Jugular blood samples were collected at mating and on Day 25 of gestation and assayed for circulating leptin concentrations. Expression levels of Lep in backfat and of Lepr and Lepr-L in endometrial and embryonic tissues were performed using semiquantitative reverse transcription-polymerase chain reaction. Results demonstrated that on Day 25 of pregnancy, the ML sows showed higher concentrations of circulating leptin along with higher backfat thickness and higher expression of Lep in backfat tissue. Moreover, in embryonic tissues, the mRNA expression levels of Lepr and Lepr-L genes were higher in ML than in YL sows. Parity effects were observed for mRNA expression of Lepr in both endometrial and embryonic tissues, whereas mRNA levels were higher in YL than in GT sows. In addition, embryonic Lepr-L mRNA levels were higher in GT than in YL sows, and B(9) + glycine dietary supplement decreased the mRNA expression levels of Lep in backfat and of Lepr in embryonic tissues. These decreases were independent of breed or parity of the sows. The effect of B(9) + glycine on Lepr-L mRNA expression levels was only seen in YL sows, whereas the treatment lowered Lepr-L expression levels in both endometrial and embryonic tissues. These results indicate that leptin and its receptor may play a role during early stages of development of the pig embryo-fetus, and that these roles could be modulated according to the breed and parity of the sows. Moreover, the effects of B(9) + glycine on expression levels of embryonic and endometrial Lepr-L mRNA in YL sows may explain the previously reported effects of B(9) on embryo survival rate and litter size observed in occidental multiparous sows.

Characterization of swine leptin (LEP) polymorphisms and their association with production traits

Four polymorphisms in the swine leptin (LEP) gene were characterized and evaluated for association with economically important production traits in Yorkshire, Landrace and Duroc pigs. Our results show that these polymorphisms are generally of low frequency or are absent in pig populations. Two polymorphisms (A2845T and T3469C) may be associated (P < 0.0078) with feed intake and growth rate traits in Landrace pigs.

Porcine leptin receptor: molecular structure and expression in the ovary

The porcine leptin receptor complementary DNA was cloned and sequenced and the leptin receptor gene expression evaluated in the porcine ovary. An open reading frame of 3498 nt cDNA was amplified from pig liver mRNA by RT-PCR. Sequence homology with the extracellular, transmembrane, and cytoplasmic domains of human, mouse, rat, sheep, and cow leptin receptors varied between 45% and 90%. Leptin receptor mRNA was present in porcine kidney, liver, spleen, lung, brain, testis, uterus, ovary, corpus luteum (CL), theca, and granulosa cells. The abundance of leptin receptor transcripts and protein varied during luteinization of granulosa cells in vitro and in the CL during the pig luteal phase. In the postovulatory CL, both mRNA and protein were low but detectable, maximal expression was observed in the midcycle CL, and lowest abundance occurred in regressed CL. Leptin receptor mRNA was present in granulosa cells at isolation and increased in abundance as the cells luteinized over 96 hr in culture. Leptin receptor protein was detectable after 12 hr of in vitro luteinization. We conclude that leptin receptor is expressed in granulosa and luteal cells, and varies during pig ovarian cell differentiation.

Mammary gland development and hormone levels in pregnant Upton-Meishan and large white gilts

Genetic differences between Upton-Meishan (UM, n = 13) and Large White (LW, n = 14) gilts were studied with regard to mammary gland development and concentrations of hormones. Gilts were weighed and their backfat measured at mating, and at d 70 and 109 of gestation. Jugular blood samples were also collected at these times and assayed for prolactin, cortisol, IGF-I, insulin, glucose, progesterone, and estradiol. Gilts were slaughtered on d 110 of gestation. One row of mammary glands was used for dissection and biochemical analyses. The other row was used for determination of prolactin receptor number and affinity. UM gilts weighed less (P<0.05) and had more backfat (P<0.01) than LW gilts at all times. Parenchymal tissue weight was less (P<0.05) in UM gilts. Percent fat (P<0.001) and dry matter (P<0.001) in parenchymal tissue were greater in UM gilts while that of protein (P<0.001) was lower. Total protein weight in parenchyma was also lower in parenchyma was also lower in UM gilts (P = 0.01). Both DNA (P<0.001) and RNA (P<0.001) contents were lower in UM gilts while RNA/DNA remained similar (P>0.1). Number of prolactin receptors were lower (P = 0.06) and affinity greater (P<0.05) in UM gilts. Cortisol levels were greater (P<0.01) in UM gilts while other hormones were not affected (P> 0.1). Results clearly demonstrate genetic differences with regard to mammogenesis in gilts and suggest that the less mammary gland development in Upton-Meishan compared with Large White breed of gilts may be related to lower number of prolactin receptors.

Inhibitory effects of Serenoa repens on the kinetic of pig prostatic microsomal 5alpha-reductase activity

The pathogenesis of benign prostatic hyperplasia is linked to the accumulation of dihydrotestosterone (DHT), the active form of testosterone (T), in prostatic tissue. We have defined characteristics of 5alpha-reductase enzyme which catalyzes the conversion of T into DHT in prostatic microsomes of growing pigs. Peaks for the 5alpha-reductase activity were found at pH 5.5 and 8.0, which indicates the presence of both type 1 and type 2 isozymes. Kinetic parameters of porcine 5alpha-reductase in the presence of Serenoa repens extracts revealed uncompetitive, noncompetitive, and mixed types of inhibitions. Our results show the inhibitory action of S. repens on prostate porcine microsomal 5alpha-reductase activity.

Ontogeny of insulin-like growth factors (IGF), IGF binding proteins, IGF receptors, and growth hormone receptor mRNA levels in porcine pancreas

We examined the ontogeny of mRNA levels of IGF-I and -II, IGF type 1 (IGFI-R) and type II receptors (IGFII-R), IGF binding protein-1 and -3 (IGFBP-1 and -3), GH receptor (GHR), and tissue concentrations of IGF and IGFBP in the pancreas of pigs. Tissues were collected from fetuses at 90 and 110 d of gestation and from pigs at 1, 21, 90 and 180 d of age. Northern blots were performed using total RNA hybridized with 32P-labeled cDNA probes (human IGF-I and human IGFI-R) and cRNA probes (rat IGF-II, human IGFII-R, human IGFBP-1, pig IGFBP-3, and pig GHR). There were two accelerated growth stages of the pancreas: the first one at 90 d of fetal life, which is characterized by cell hyperplasia (high ratio of DNA to body weight), and the second one at postnatal 90 d, which is attributed to cell hypertrophy (high ratios of pancreatic weight, RNA, and protein to DNA). The level of IGF-II mRNA and its tissue concentration were predominant during fetal life and low thereafter. The IGF-I mRNA level was high during fetal and early postnatal life and decreased thereafter. Messenger RNA levels of IGFI-R, IGFBP-3, and GHR and concentrations of IGFBP-1 and -2 were abundant during fetal and early postnatal life. In conclusion, IGF may be involved in various physiological periods of pancreatic development in pigs.

Ontogeny of epidermal growth factor (EGF), EGF receptor (EGFR) and basic fibroblast growth factor (bFGF) mRNA levels in pancreas, liver, kidney, and skeletal muscle of pig

Epidermal growth factor (EGF), EGF receptor (EGFR), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) levels were examined by Northern blot analysis in four tissues (pancreas, liver, kidney, and skeletal muscle) of pig from fetal 90 d to postnatal 180 d of age. The present study shows for the first time that EGF mRNA increased with advancing age in the kidney and skeletal muscle of pig. A high level of EGF mRNA was observed in the kidney compared with the liver and skeletal muscle. In the pancreas, high levels of EGF mRNA were found in fetuses and newborns and were low in older pigs. Pancreatic EGFR mRNA level parallelled its EGF mRNA, whereas in the kidney and skeletal muscle, patterns of EGFR mRNA were reversed to their EGF mRNA levels. In the liver, EGFR mRNA was abundant but EGF mRNA was undetected. In the pancreas and skeletal muscle, the highest levels of bFGF mRNA were found in fetuses of 90 d of age and then decreased with advancing age. In the liver and kidney, there were no major changes in bFGF mRNA levels during the examined developmental periods. These results show that EGF, EGFR, and bFGF mRNA levels are developmentally and tissue specifically regulated in pig. In the pancreas, mRNA levels of EGF, EGFR and bFGF were high in fetal and neonatal life and low thereafter. In the kidney and skeletal muscle, EGF mRNA increased with advancing age. EGF may play a role in muscle growth and maintenance in growing pigs during the later stage of development.

Direct expression of mature bovine adrenodoxin in Escherichia coli

Site-directed mutagenesis was utilized to enable direct expression of the mature form of bovine adrenodoxin cDNA using the pKK223-3 expression vector in Escherichia coli. Expression was under control of the "tac" promoter and resulted in a direct expression of soluble mature bovine adrenodoxin (greater than 15 mg per liter). Chromatographic behavior of recombinant adrenodoxin did not differ from that reported for mature native adrenodoxin. The purified recombinant protein was identical to native mitochondrial adrenodoxin on the basis of molecular weight, NH2 terminal sequencing and immunoreactivity. E. coli lysates were brown in color, and the purified protein possessed a visible absorbance spectra identical to native bovine adrenodoxin consistent with incorporation of a [2Fe-2S] cluster in vivo. Recombinant bovine adrenodoxin was active in cholesterol side-chain cleavage when reconstituted with adrenodoxin reductase and cytochrome P450scc and exhibited kinetics reported for native bovine adrenodoxin. The presence of the adrenodoxin amino terminal presequence does not appear to be essential for correct folding of mature recombinant adrenodoxin in E. coli. This expression system should prove useful for overexpression of adrenodoxin mutants in future structure/function studies. The approach described herein can potentially be used to directly express the mature form of any protein in bacteria.