W. L. Flowers

Iron methionine as a source of iron for the neonatal pig

Neonatal pigs (143) were used to determine if adequate iron (Fe) would be stored following a single oral dose of Fe methionine (FeMet) to prevent anemia through 21 d of age. Treatments consisted of: control (no Fe), 200 mg injectable Fe as gleptoferron within 12 h of birth (at birth), 100 or 200 mg Fe as FeMet orally at birth, or 200 mg Fe as FeMet or FeSO4 orally on d 3. Pigs given injectable Fe had higher hemoglobin concentrations than other treatments at 14 and 21 d. Utilization of Fe from FeMet was greatest when given at 3 d compared to at birth. Based on hemoglobin concentrations at 21 d, relative bioavailability of Fe from FeMet given on d 3 was 180% compared to FeSO4. Iron methionine given orally was a safe, effective source of Fe, but a single oral dose of FeMet was not equivalent to injectable Fe.

Effects of stress associated with weaning on the adaptive immune system in pigs

This study was designed to investigate the effects of weaning age on specific components of the adaptive immune system in pigs. Twenty-three crossbred pigs were randomly assigned to 1 of 3 treatments: weaning at 14 (14D, n = 8), 21 (21D, n = 7), or 28 (28D, n = 8) d of age. Peripheral blood samples, obtained when pigs were 13, 15, 20, 22, 27, 29, and 35 d of age, were analyzed for peripheral blood cell percentages and concentrations of neutrophils, lymphocytes, T cell subsets, mature B cells, and plasma cortisol concentrations. For each of the 3 groups, weaning increased plasma cortisol concentrations (P < 0.001) and reduced BW percentage change (P < 0.017). Lymphocyte concentrations displayed a treatment effect for the 14D (P = 0.074) and 28D (P = 0.014) groups. Albeit inconsistent, lymphocyte concentrations were less in weaned pigs on the day after weaning than in pigs remaining on the sow or weaned at a younger age. Specifically, mature B cells (CD21(+)) and CD4(+)CD8(+) cells decreased (P < 0.05) after weaning at 28 d of age. Other differences occurred among treatments; however, the differences apparently were not associated with weaning. Based upon the immunological measures used in the present study, there was not an explicit benefit to the adaptive immune system for any weaning age. Early weaning did not negatively affect the adaptive immunological competence of pigs as determined by changes in populations of immune cells.

Effect of social ranks and gestation housing systems on oxidative stress status, reproductive performance, and immune status of sows

Ninety-six multiparous sows were randomly assigned into 2 different gestation housing systems on d 35 of gestation: individual gestational crates (n = 24) or small groups with 3 sows in gestational pens (n = 24). Sows were classified into 4 treatments based on gestation housing systems and social ranks within each gestational pen: sows housed in individual gestational crates were in control treatment (CON), and sows destined to high, middle, or low social ranks within each pen were classified into high social rank treatment (HR), middle social rank treatment (MR), and low social rank treatment (LR). The social rank of sows within a pen was determined by their winning percentage during aggressive interactions observed for a 4-d period after mixing on d 35 of gestation. Plasma samples collected from each sow on d 35, 60, 90, and 109 of gestation and d 1 and 18 of lactation were used to determine concentrations of malondialdehyde (MDA), protein carbonyls, 8-hydroxy-deoxyguanosine (8-OHdG), IgG, and IgM. Sows in HR had higher (P < 0.05) body weight during gestation and lactation, smallest (P < 0.05) litter weight at birth, increased (P < 0.05) number of stillborn than sows in MR and LR, and tended to have decreased (P = 0.073, P = 0.064) number of born alive compared with sows in CON and LR. Sows in LR had lower farrowing rate compared with sows in MR. Plasma concentration of protein carbonyl in HR was higher (P < 0.05) than that in MR on d 3 of lactation. Plasma concentrations of 8-OHdG in LR was greater (P < 0.05) than that in HR on d 90 of gestation, d 3 and 18 of lactation, and greater (P < 0.05) than CON on d 18 of lactation. The reproductive performance of sows from all of the social ranks was related to their oxidative stress status during gestation and lactation. Collectively, the reproductive performance, oxidative stress status, and immune status did not differ between sows housed in gestational crates (CON) and pens (HR + MR + LR). Sows in CON and MR did not show inferior reproductive performance during gestation and lactation. Sows in HR and LR had increased oxidative damage during late gestation and lactation which could contribute to the reduced litter size and litter weight in HR and lower farrowing rate in LR.

TRIENNIAL REPRODUCTION SYMPOSIUM: Sperm characteristics that limit success of fertilization

Current industry estimates of reproductive performance for cattle, sheep, and swine operations indicate that males contribute significantly to fertility failures. This appears to be due to the use of subfertile individuals and emphasizes the need for additional research in identifying characteristics of sperm that compromise fertilization. In theory, sperm characteristics, such as motility or the percentage of normal sperm, form a positive relationship with fertility that reaches a certain maximal fertility (i.e., an asymptotic relationship). It is clear that variation exists among males in terms of how fertility responds to increasing sperm dosage or numbers of normal sperm, both in the slope of the curve and the point at which the fertility reaches a maximum. Variations along the linear portion of fertility curves are due to compensable traits that are involved with the ability of sperm to penetrate the zona pellucida. It appears that most fertility curves reach their plateau when 70% of sperm possess a given compensable trait. The level of fertility at which the plateau occurs is determined by noncompensable traits that are associated with binding of sperm to the oolemma, syngamy, and subsequent development of the zygote. Several studies have shown differences in fertility among males that have similar levels of compensable traits but differed in their noncompensable characteristics. Compensable and noncompensable traits can estimate either individual or functional characteristics of sperm. Intuitively, functional traits such as in vitro penetration should provide a better indication of fertilization than individual ones such as motility. However, correlations of both types with fertility are very similar. Reasons for this may be related to how characteristics of sperm cells are influenced by the female reproductive tract after insemination. Sperm capacitation is a functional trait in boars that is quite different in vitro versus in vivo. If this relationship holds true for other traits, then development of tests that account for this variation are critical for further elucidation of sperm characteristics that limit fertility.

Blocking Ligand Occupancy of the αVβ3 Integrin Inhibits the Development of Nephropathy in Diabetic Pigs

Hyperglycemia stimulates secretion of αVβ3 ligands from vascular cells, including endothelial cells, resulting in activation of the αVβ3 integrin. This study determined whether blocking ligand occupancy of αVβ3 would inhibit the development of diabetic nephropathy. Ten diabetic pigs received an F(ab)2 fragment of an antibody directed against the extracellular domain of the β3-subunit, and 10 received a control IgG F(ab)2 for 18 weeks. Nondiabetic pigs excreted 115 ± 50 μg of protein/mg creatinine compared with control F(ab)2-treated diabetic animals (218 ± 57 μg/mg), whereas diabetic animals treated with the anti-β3 F(ab)2 excreted 119 ± 55 μg/mg (P < .05). Mesangial volume/glomerular volume increased to 21 ± 2.4% in control-treated diabetic animals compared with 14 ± 2.8% (P < .01) in animals treated with active antibody. Diabetic animals treated with control F(ab)2 had significantly less glomerular podocin staining compared with nondiabetic animals, and this decrease was attenuated by treatment with anti-β3 F(ab)2. Glomerular basement membrane thickness was increased in the control, F(ab)2-treated diabetic animals (212 ± 14 nm) compared with nondiabetic animals (170 ± 8.8 nm), but it was unchanged (159.9 ± 16.4 nm) in animals receiving anti-β3 F(ab)2. Podocyte foot process width was greater in control, F(ab)2-treated, animals (502 ± 34 nm) compared with animals treated with the anti-β3 F(ab)2 (357 ± 47 nm, P < .05). Renal β3 tyrosine phosphorylation decreased from 13 934 ± 6437 to 6730 ± 1524 (P < .01) scanning units in the anti-β3-treated group. We conclude that administration of an antibody that inhibits activation of the β3-subunit of αVβ3 that is induced by hyperglycemia attenuates proteinuria and early histologic changes of diabetic nephropathy, suggesting that it may have utility in preventing the progression of this disease complication.

Amount and source of dietary copper affects small intestine morphology, duodenal lipid peroxidation, hepatic oxidative stress,and mRNA expression of hepatic copper regulatory proteins in weanling pigs 1 2

Thirty weanling, crossbred barrows (SUS SCROFA) were used to determine the effects of amount and source of dietary Cu on small intestinal morphology and lipid peroxidation, Cu metabolism, and mRNA expression of proteins involved in hepatic Cu homeostasis. At 21 d of age, pigs were stratified by BW (6.33 ± 0.23 kg) and allocated to 1 of the following dietary treatments: i) control (no supplemental Cu; 6.7 mg Cu/kg), ii) 225 mg supplemental Cu/kg diet from Cu sulfate (CuSO(4)), or iii) 225 mg supplemental Cu/kg diet from tribasic Cu chloride (TBCC). Pigs were housed 2 pigs per pen and were fed a 3-phase diet regimen until d 35 or 36 of the study. During harvest, bile and liver were obtained for mineral analysis, and liver samples were also obtained for analysis of liver glutathione (GSH) and mRNA expression of Cu regulatory proteins. Segments of duodenum, proximal jejunum, and ileum were obtained for mucosal morphology, and duodenal mucosal scrapings were collected from all pigs for analysis of malondialdehyde (MDA). Duodenal villus height was reduced in CuSO(4) pigs compared with control (P = 0.001) and TBCC (P = 0.03) pigs. Villus height in the proximal jejunum of CuSO(4) pigs was reduced (P = 0.03) compared with control pigs, but ileal villus height was not affected (P = 0.82) by treatment. Duodenal MDA concentrations were greater (P = 0.03) in CuSO(4) pigs and tended to be greater (P = 0.10) in pigs supplemented with TBCC compared with control pigs. Liver Cu was greater (P = 0.01) in CuSO(4) vs. control pigs, and tended (P = 0.07) to be greater in TBCC pigs than control pigs. Bile Cu concentrations were greater (P < 0.001) in CuSO(4) and TBCC pigs vs. controls and were also greater (P = 0.04) in TBCC vs. CuSO(4) pigs. Total liver GSH concentrations were less (P = 0.02) in pigs fed diets supplemented with CuSO(4) vs. pigs fed control diets but total liver GSH did not differ (P = 0.11) between control and TBCC pigs. Hepatic mRNA of cytochrome c oxidase assembly protein 17 was less (P = 0.01) in CuSO(4) and tended to be less (P = 0.08) in TBCC pigs vs. control pigs. Expression of antioxidant 1 mRNA was greater (P = 0.04) in TBCC pigs and tended to be greater (P = 0.06) in CuSO(4) pigs compared with control pigs. Results of this study indicated that, when fed at 225 mg Cu/kg diet, TBCC may cause less oxidative stress in the duodenum than CuSO(4). Feeding weanling pigs increased Cu resulted in modulation of certain Cu transporters and chaperones at the transcription level.

Effect of dietary selenium on boar sperm quality.

The primary objective of this research was to evaluate the effect of long-term dietary selenium supplementation of commercial swine diets on semen production and sperm quality. The dietary treatments were a non-supplemented basal diet or the basal diet supplemented with 0.3ppm selenium in either an organic or inorganic form. A secondary objective was to determine if there were any beneficial effects of dietary selenium supplementation on changes in sperm quality during storage of semen post collection. Boars were fed dietary treatments from weaning at 20.97±0.18 d of age until the study was terminated when they were 382.97±0.18 d of age. Boars (n=6 per treatment) were maintained on a 1 time per week collection frequency for 5 months. Immediately after this, boars were collected six times over a 4 day period. Ejaculates were extended in a commercially available, 5-day semen extender and evaluated on day 1 and 6 of storage post-collection. Boars fed the organic selenium had higher (P<0.01) plasma levels of selenium compared to control boars and similar levels to those supplemented with the inorganic form (P=0.18). Dietary treatment did not affect (P>0.2) volume, concentration, total sperm in the ejaculate, sperm motility, progressive motility, morphology, lipid peroxidation, or glutathione peroxidase activity. These results indicate that supplementing a basal diet with organic or inorganic selenium did not affect semen quantity or sperm quality in fresh ejaculates nor did it appear to have any beneficial latent effects in extended semen stored post collection.

Effect of dietary copper amount and source on copper metabolism and oxidative stress of weanling pigs in short-term feeding.

Forty-eight weanling barrows were used to determine the effects of amount and source of dietary Cu on Cu metabolism, oxidative stress in the duodenum, and VFA ratios in the cecum of weanling pigs in short-term feeding. At 21 d of age, newly weaned pigs were stratified by BW (7.03 ± 1.20 kg) and equally assigned to 1 of the following dietary treatments: 1) control (5 mg supplemental Cu/kg diet from CuSO4), 2) 225 mg supplemental Cu/kg diet from CuSO4, or 3) 225 mg supplemental Cu/kg diet from tribasic Cu chloride (TBCC). Pigs were housed 2 pigs per pen and were fed a complex diet until harvest on d 11 and 12. During harvest, bile and liver were obtained for mineral analysis, and liver samples were obtained for analysis of mRNA expression of Cu regulatory proteins. Digesta of duodenum, proximal jejunum, and ileum were collected for soluble Cu analysis. Mucosal scrapings of duodenum, proximal jejunum, and ileum were obtained for analysis of mucosal Cu concentration and mRNA expression of Cu regulatory proteins. Duodenal mucosal scrapings were also collected for analysis of malondialdehyde (MDA). Pigs fed high Cu had markedly greater (P < 0.0001) Cu concentrations in the duodenal, proximal jejunal, and ileal mucosa than controls. Copper in the duodenal mucosa was greater (P = 0.003) in CuSO4 than TBCC pigs. Duodenal MDA concentrations were greater (P = 0.003) in CuSO4 vs. control pigs and tended (P = 0.06) to be greater than in TBCC pigs. Duodenal antioxidant 1 (Atox1) mRNA was downregulated (P < 0.01) in pigs fed high Cu compared to controls and was not affected by Cu source. Compared with control pigs, those fed CuSO4 and TBCC had greater (P < 0.001) liver and bile Cu concentrations. Liver Cu was also greater (P = 0.0007) in TBCC than CuSO4-fed pigs. Hepatic Cu transporting β-polypeptide ATPase (Atp7b) was upregulated (P = 0.02) in the Cu-supplemented pigs compared with controls and did not differ among Cu sources. The acetate:propionate ratio in cecal contents was much greater in pigs supplemented with 225 mg Cu/kg diet than in controls. When fed at 225 mg Cu/kg diet, TBCC may cause less oxidative stress in the duodenum than CuSO4. Feeding weanling pigs increased Cu resulted in modulation of duodenal and liver at the transcription level.

Use of heterospermic inseminations and paternity testing to evaluate the relative contributions of common sperm traits and seminal plasma proteins in boar fertility

The objective of this study was to evaluate relationships between common semen quality estimates including sperm motility, sperm morphology, spontaneous capacitation status and seminal plasma proteins and boar fertility using heterospermic inseminations and subsequent paternity testing. All boars (n=12) used in the study had excellent semen quality (≥70% normal sperm) that resulted in average farrowing rates and litter sizes of 88.9±0.7% and 11.7±0.1 pigs, respectively. Their ejaculates were combined to make heterospermic insemination doses in such a way that each boar was tested against all of his contemporaries. The proportion of piglets sired by each individual was used to separate boars into three fertility groups: High (71.6±4.8%; n=3); Medium (51.6±3.8%; n=6); and Low (25.2%±5.3%; n=3). Ejaculates from High fertility boars had more motile sperm with normal acrosomes that moved faster in a straight-line and were more likely to undergo an acrosome reaction (p≤0.05) compared with their counterparts in the Low fertility group. Ejaculates from High fertility boars contained the greatest concentrations of three seminal plasma proteins (25.9kD/5.9pI; 55.1kD/4.8pI; and 70.1kD/5.2pI; p≤0.05), whereas concentrations of a 19.1kD/6.8pI were highest in semen from Low fertility boars (p≤0.05). Multiple regression analyses indicated that concentrations of the 25.9kD/5.9pI seminal plasma protein explained 66% of the variation observed in the proportion of pigs sired within a litter among boars (p≤0.00001). These results demonstrate that heterospermic inseminations and subsequent paternity testing is an effective technique for defining relationships between common semen quality tests and fertility, especially in situations where reproductive performance of all the boars is high. Motility, normal acrosome morphology, average linear velocity of motile sperm, and the proportion of sperm capable of an acrosome reaction were all positively associated with boar fertility. However, concentrations of a 25.9kD/5.9pI seminal plasma protein were the best single semen characteristic for ranking boars in terms of their fertility.

Effect of gonadotropin releasing factor suppression with an immunological on growth performance, estrus activity, carcass characteristics, and meat quality of market gilts

Objectives were to evaluate the administration of an anti-gonadotropin releasing factor (GnRF) analog on suppression of estrus, consistency of feed intake, and growth performance in market gilts and to investigate the impact the physiological changes would have on carcass characteristics and fresh meat quality. Gonadotropin releasing factor stimulates the anterior pituitary to release luteinizing hormone that acts on the ovary to induce follicle development and indirectly initiates ovulation. Improvest (Zoetis, Kalamazoo, MI) contains an incomplete version of naturally occurring GnRF and causes the production of anti-GnRF antibodies that bind to the GnRF receptor and thus render GnRF inactive. This in turn suppresses estrus in female pigs. Gilts were initially separated into 10 blocks based on age and then within each block allotted to a pen (n = 114; 5 pigs/pen) based on BW. Gilts received the first dose at 12 wk of age and the second dose at 16 wk of age, were exposed to a boar daily from 20 to 26 wk of age, and were slaughtered at 26 wk of age (10 wk after second dose). Meat quality was analyzed on the 2 gilts closest to pen average ending live weight in 5 of the 10 blocks. Pen served as the experimental unit for all data analysis. During the 15-wk finishing period, ADG was 0.03 kg greater (P < 0.01) and G:F was 0.009 greater (P = 0.02) in gilts administered GnRF suppression (treated) compared with untreated gilts (control). The majority of improvements in growth performance were observed from 16 to 20 wk of age (4 wk after second dose), as ADG was 0.07 kg greater (P < 0.001) and G:F was 0.021 greater (P < 0.01) in treated gilts compared with control gilts. Ovarian weights were reduced (P < 0.0001) by 64.15% and gilts exhibiting puberty were reduced by 87.80% (P < 0.001) in treated gilts compared with control gilts. Back fat depth was 3.78 mm greater (P < 0.0001) and estimated lean was 1.31 percentage units less (P < 0.0001) in treated gilts compared with control gilts. With the exception of subjective color, there were no differences (P ≥ 0.12) in meat quality parameters between treated and control gilts. Subjective color was darker (P = 0.03) in treated gilts compared with control gilts. These data suggest market gilts treated with an anti-GnRF analog had suppressed estrus and episodical changes in ADFI, while they had improved feed efficiency, increased ADG, and increased back fat depth when compared with gilts without an anti-GnRF analog treatment.