Methionine,folic acid and vitamin B12 in growing-finishing pigs: Impact on growth performance and meat quality

Growth performance, metabolic variables, and meat quality were measured in 78 growing-finishing pigs using supplements of 0 (C), or 0.2% of DL-methionine (M), and three combinations of folic acid [mg/kg] and cyanocobalamin [μg/kg], respectively 0 and 0 (V0), 10 and 25 (V1), and 10 and 150 (V2) in a 2 × 3 factorial arrangement. Feed conversion was lower (p = 0.05) in M than in C pigs during the growing period (0–4 weeks). Both V1 and V2 treatments increased plasma vitamin B₁₂ (p < 0.01) and decreased plasma homocysteine (p < 0.01). Plasma 5-methyl-tetrahydrofolates were the lowest, highest and intermediate in V0, V1 and V2 pigs (p < 0.04), respectively. In V2 meat, folates were 32% higher, vitamin B₁₂, 55% higher and homocysteine, 28% lower than in V0 (p < 0.01). Oxidative stability of the fresh meat was similar among treatments during a storage period of 42 days. Therefore, methionine supplements improved growth performance during the growing period. Vitamin supplements interacted with the methionine cycle pathway, increased vitamin content of pork meat but did not improve oxidative stability of the fresh meat during storage.     

Impairments in pyridoxine-dependent sulphur amino acid metabolism are highly sensitive to the degree of vitamin B6 deficiency and repletion in the pig

The objectives of the current study included the characterization of the temporal changes in indices of sulphur amino acid metabolism in piglets in response to vitamin B6 deficiency and repletion with graded levels of pyridoxine hydrochloride. In Experiment 1, 12 piglets (average initial weight = 5.3 kg; n = 6 per group) were fed a semi-purified diet containing either 0 (deficiency group) or 3 mg (control group) pyridoxine·HCl/kg diet, using a pair-feeding design, for 6 weeks. Piglets consuming vitamin B6-deficient diets exhibited decreased average daily gains on the 4th week and feed conversion efficiency from the 4th week until the end of the trial (P < 0.05). Plasma pyridoxal-5'-phosphate (PLP), in pigs consuming vitamin B6-deficient diets, was significantly lower than controls throughout the experiment (P < 0.01), reaching a nadir of 14% of the control animals' value by the end of the trial. Indices of sulphur amino acid metabolism, including activities of hepatic cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CGL) and serine hydroxymethyltransferase, as well as hepatic-free cysteine concentrations were markedly decreased after 6 weeks of B6 deficiency (P < 0.05). Total hepatic mRNA expressions for CBS and CGL were not affected. Concurrently, hepatic-free homocysteine concentrations increased by more than eight-fold (P < 0.01) at the end of the trial. An examination of plasma total homocysteine and cysteine concentrations revealed significant (P < 0.05) differences between treatments, with evidence of an abrupt shift in concentrations at 3 weeks post-initiation of dietary treatments (>25-fold increase in homocysteine; halving of cysteine values). At the end of Experiment 1, vitamin B6 deficiency significantly increased plasma methionine and serine levels, but decreased plasma glycine concentrations (P < 0.05). In Experiment 2, 20 pigs of 14 days old (initial BW = 5.0 kg) were subjected to a 4-week vitamin B6 depletion protocol, based on results obtained in Experiment 1. After the depletion period and assessment of baseline status (four pigs), remaining pigs were allocated to one of four dietary vitamin B6 repletion treatments: 0.75, 1.5, 2.25 and 3 mg/kg diet as pyridoxine·HCl (n = 4 per level) for 14 days. Significant dose-dependent increases in plasma PLP and cysteine, and decreases in homocysteine were observed, and these were sensitive to the duration of repletion. In conclusion, data from the current studies support the use of both plasma PLP and homocysteine as sensitive indices of vitamin B6 status in the pig. Additionally, the observed patterns of responses in vitamin B6-sensitive metabolites are supportive of an inclusion level of 2.25 mg/kg diet, as pyridoxine·HCl, in diets for young pigs.     

Effect of Dietary Fat Quality and Vitamin E on the Antioxidant Potential of Pigs

A randomized blocked factorial experiment was conducted with 90 young pigs. From 4 to 11 weeks of age the pigs were kept in individual pens and fed a selenium supplemented basal diet consisting mostly of propionic acid treated barley, soybean meal and dried skim milk, and containing < 0.5 mg vitamin E per kg. The treatment factors during this period were 3 dietary levels of added vitamin E (nil, 10 and 30 mg/kg) and a 6 % supplement of fresh or oxidized fat (2/3 lard and 1/3 herring oil). From 11 weeks of age until slaughter at 90 kg the pigs received the vitamin E supplements but no fat or dried skim milk. The basal diet for this later experimental period was based on untreated dry barley. Blood samples collected during the period of investigation were examined for vitamin E and for resistance against erythrocyte lipid peroxidation (ELP) in order to evaluate the antioxidant status. Analysis of variance and Student’s t-test on least squares means showed the ELP to be influenced independently by the vitamin E supplement and, during the fat feeding period, by the quality of the fat supplement, with the highest peroxidation resistance (low ELP) in the groups fed fresh fat and a high level of vitamin E. Blood vitamin E level was only influenced — positively — by the vitamin E supplement although variations in the feed vitamin E level below 10–15 mg vitamin E per kg did not result in corresponding variations in measurable blood vitamin E concentrations. In the same low range of vitamin E in the feed there was a statistically significant difference in ELP values between the different vitamin E treatment groups. No clinical manifestations of selenium-vitamin E deficiency were observed in the pigs. The ELP and the plasma vitamin E levels observed would seem to suggest that a total of 15 mg vitamin E per kg barley-based feed will not always be sufficient for growing pigs.     

Meat meal in the diet of the early-weaned pig IV. The supplementation of diets with tryptophane,lysine and methionine

Two experiments were conducted with 72 pigs between 28 and 56 days of age to study the effect of tryptophane supplementation on their performance when fed on diets containing wheat and meat meal.In the first experiment, pigs were fed on a basal diet (Diet 1) or on the same diet supplemented with calcium dihydrogen phosphate (Diet 2), bone meal (Diet 3) or bone meal plus tryptophane (Diet 4), all to 3.1% calcium. The weight gains of the pigs (315 g day^?1) fed on Diet 3 were significantly lower than that of the pigs fed on the other three diets (363 g day^?1). The feed conversion ratios showed a similar trend. Diet 3 contained 0.16% tryptophane while the other diets contained 0.18–0.19% tryptophane. The crude protein, lysine and methionine contents of all diets were similar.In the second experiment, a basal diet containing meat meal and bone meal was supplemented with tryptophane, lysine plus methionine or all three amino acids. Feed intake was increased by all amino acid supplements. Weight gains were improved significantly (57%) by the addition of all three amino acids to the diets, but the improvements due to tryptophane alone (28%) or methionine plus lysine (35%) were not significant. Tryptophane supplementation alone or with lysine plus methionine increased the nitrogen retention of the pigs.It was concluded that the requirement for tryptophane of pigs between 28 and 56 days of age was greater than 0.16% of diets containing wheat and meat meal.     

Effect of oat by-product antioxidants and vitamin E on the oxidative stability of pork from pigs fed diets supplemented with linseed oil

The aim of the experiment was to compare the antioxidative potential of an oat by-product with the effect of vitamin E on the oxidative stability of pork from pigs fed a diet enriched with linseed oil. Thirty-four crossbreed barrows were fed individually from 39 to 109 kg body weight (BW) on one of four diets: a control diet based on barley-triticale-soybean (Diet C), a diet containing an oat byproduct (Diet O), and the same diets supplemented with vitamin E (100 mg/kg diet) (Diets CE and OE, respectively). The oat by-product, comprising oat hulls and bran, was included at 10 and 20% in the grower and finisher diets, respectively. To Diets O and OE, refined rapeseed oil was added to equalise their energy content to Diets C and CE. Compared to Diets C and CE, the inclusion of the oat by-product in Diets O and OE increased the antioxidative capacity of water-soluble and lipid soluble compounds in these diets. Dietary treatment did not influence growth performance, slaughter value, longissimus dorsi (LD) muscle quality measured by nutrient contents, pH, drip loss or colour. Vitamin E supplementation increased the alpha-tocopherol concentration in serum and meat (p < 0.01), and decreased the formation of thiobarbituric acid reactive substances (TBARS) in the fresh and stored LD (p < 0.01). In addition, diets with the oat by-product increased serum alpha-tocopherol concentration (p < 0.01) and decreased the TBARS levels in the fresh and stored LD (p < 0.05), without increasing muscle alpha-tocopherol concentration. The obtained results indicate that the phenolic compounds present in oat by-products have a considerable antioxidant potential and a beneficial effect on the pig organism and oxidative stability of meat. However, dietary inclusion with the oat by-product was not as efficient as supplementation with vitamin E.     

Nonsyndromic orofacial clefts: association with maternal hyperhomocysteinemia.

Maternal folic acid supplementation has been suggested to play a role in the prevention of nonsyndromic orofacial clefts, i.e., cleft lip +/- cleft palate. Using a case-control design, we investigated vitamin-dependent homocysteine metabolism in 35 mothers with nonsyndromic orofacial cleft offspring and 56 control mothers with nonmalformed offspring. A standardized oral methionine loading test was performed, in which fasting and afterload plasma total homocysteine, serum and red-cell folate, serum vitamin B12, and whole-blood vitamin B6 levels were determined. We found that both fasting (P < 0.01) as well as afterload (P < 0.05) homocysteine concentrations were significantly higher in cases compared to controls. Hyperhomocysteinemia, defined by a fasting and/or afterload homocysteine concentration above the 97.5th percentile, was present in 15.6% of the cases and in 3.6% of controls (odds ratio, 5.3 (1.1-24.2)). The median concentrations of serum (P < 0. 01) and red-cell (P < 0.05) folate were significantly higher, and vitamin B6 concentrations appeared to be significantly lower (P < 0. 05), in cases compared with controls. No significant difference was observed between groups for vitamin B12. These preliminary data offer evidence that maternal hyperhomocysteinemia may be a risk factor for having nonsyndromic orofacial cleft offspring.     

Effects of supplementing two levels of magnesium aspartate and transportation stress on pork quality and gene expression of micro-calpain and calpastatin of finishing pigs

The objective of this study was to investigate the effects of supplementing swine finishing diets with two levels of magnesium aspartate (MgAsp) and short-term transportation stress on blood parameters, pork quality and the mRNA abundance of p-calpain and calpastatin in muscles of finishing pigs. Thirty-six crossbred finishing pigs (mean BW 90 kg) were assigned randomly to 0, 1000, or 2000 mg supplemental Mg from MgAsp per kg of diet for five days before slaughter. Then six pigs from each dietary treatment were subjected either to no transportation stress (NTS) or 2 h of transportation stress (TS). Transportation stress resulted in higher concentrations (p < 0.01) of serum calcium, glucose and cortisol, lower pH (p < 0.01), higher Warner-Bratzler shear force (WBSF) (p < 0.05) and higher calpastatin mRNA abundance (p = 0.05) of longissimus muscle (LM) compared with NTS treatments. Supplementation of MgAsp in TS treatments increased serum Mg concentration (p < 0.05) at 2000 mg of Mg/kg, reduced drip loss (p < 0.05) and improved pork quality colour (p < 0.05) at 2000 mg of Mg/kg, and decreased 1-day and 3-day WBSF (p < 0.05) at 1000 mg of Mg/kg compared with TS treatments fed the control diet. It is concluded that supplementation of MgAsp improves water-holding capacity and pork colour, and alleviates the negative effects of transportation stress on meat tenderness.     

Effect of feed restriction on the performance and behaviour of pigs immunologically castrated with Improvac®

For centuries, entire male pigs have been castrated to reduce the risk of boar taint. However, physical castration of pig is increasingly being questioned with regard to animal welfare considerations. Immunization against gonadotrophin releasing hormone (GnRH) provides an alternative to physical castration. Using the currently available commercial product (Improvac®; Pfizer Animal Health), a two-dose regimen of a GnRH vaccine is administered. After the second vaccination, a substantial increase in feed consumption has been reported, which may be associated with increased body fatness and decreased feed efficiency when compared with unvaccinated entire male pigs. The aim of the present study was to investigate the effect of a feed restriction on these traits and on the behaviour of 120 group-housed entire males (five pigs/pen) vaccinated against GnRH. The first vaccination was performed at 62 days of age and the second (V2) at 130 days of age. Pigs were slaughtered in two batches 4 to 5 weeks after V2. They were either offered feed ad libitum over the 22 to 114 kg BW range (AL treatment) or ad libitum up to a maximum of 2.50 (R2.50 treatment) or 2.75 kg/day per pig (R2.75 treatment). Behavioural observations and skin lesion scoring were conducted 1 week before V2, and 1 and 3 weeks after V2. At slaughter, the volumetric lean meat content was measured using an X-ray computed tomography scanner. Between V2 and slaughter, the average feed intakes for the R2.75 and R2.50 treatments were 15% and 22% lower than the average AL feed intake (3.20 kg/day), respectively. Feed restriction was associated with a reduced average daily gain after V2 (846, 932 and 1061 g/day in the R2.50, R2.75 and AL groups, P < 0.01) but had no effect on the feed conversion ratio (3.00 kg feed/kg BW gain on average, P = 0.62). No difference was observed in the lean meat content (71.8%, 70.7% and 70.4% in the R2.50, R2.75 and AL groups, P = 0.14), despite a reduced backfat thickness measured in restrictively fed pigs (12.0, 13.0 and 13.6 mm in the R2.50, R2.75 and AL groups, P < 0.01). Higher skin lesion scores were observed 3 weeks after V2 in R2.50 and R2.75 pigs than in the AL ones (scores 33.4, 27.7 and 25.5, respectively, P = 0.04). These results, combined with an unimproved feed efficiency and no marked change in carcass characteristics, suggest that immunologically castrated pigs should not be restrictively fed during the late finishing period.     

Insulin in methionine and homocysteine kinetics in healthy humans: plasma vs. intracellular models

Methionine is a sulfur-containing amino acid that is reversibly converted into homocysteine. Homocysteine is an independent cardiovascular risk factor frequently associated with the insulin resistance syndrome. The effects of insulin on methionine and homocysteine kinetics in vivo are not known. Six middle-aged male volunteers were infused with L-[methyl-2H3,1-13C]methionine before (for 3 h) and after (for 3 additional hours) an euglycemic hyperinsulinemic (150 mU/l) clamp. Steady-state methionine and homocysteine kinetics were determined using either plasma (i.e., those of methionine) or intracellular (i.e., those of plasma homocysteine) enrichments. By use of plasma enrichments, insulin decreased methionine rate of appearance (Ra; both methyl- and carbon Ra) by 25% (P < 0.003 vs. basal) and methionine disposal into proteins by 50% (P < 0.0005), whereas it increased homocysteine clearance by approximately 70% (P < 0.025). With intracellular enrichments, insulin increased all kinetic rates, mainly because homocysteine enrichment decreased by approximately 40% (P < 0.001). In particular, transmethylation increased sixfold (P < 0.02), transsulfuration fourfold (P = 0.01), remethylation eightfold (P < 0.025), and clearance eightfold (P < 0.004). In summary, 1) physiological hyperinsulinemia stimulated homocysteine metabolic clearance irrespective of the model used; and 2) divergent changes in plasma methionine and homocysteine enrichments were observed after hyperinsulinemia, resulting in different changes in methionine and homocysteine kinetics. In conclusion, insulin increases homocysteine clearance in vivo and may thus prevent homocysteine accumulation in body fluids. Use of plasma homocysteine as a surrogate of intracellular methionine enrichment, after acute perturbations such as insulin infusion, needs to be critically reassessed.     

Effects of keratinase supplementation of corn-soybean meal based diets on apparent ileal amino acid digestibility in growing pigs and serum amino acids, cytokines, immunoglobulin levels and loin muscle area in nursery pigs

Two experiments were conducted to evaluate effects of keratinase for growing and nursery pigs. In Exp. 1, six pigs (32.3 +/- 2.8 kg body weight), fitted with a simple T-cannula at the distal ileum, were assigned to one of two 3 x 3 Latin squares involving three periods and three diets including a basal diet and the same diets supplemented with 0, 0.05 or 0.1% keratinase. Dietary keratinase supplementation increased the apparent ileal digestibility of crude protein (CP), arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, alanine, glutamic acid and proline (p < 0.05). Digestibility coefficients did not differ between pigs fed 0.05 and 0.1% keratinase. In Exp. 2, 24 piglets weaned at 30 +/- 2 d of age were used in a 2 x 2 factorial design experiment with two CP concentrations (19 vs. 22%) and two levels of keratinase supplementation (0 vs. 0.05%). Keratinase supplementation increased (p < 0.05) average daily gain, serum arginine concentration and loin muscle area but decreased (p < 0.05) serum interleukin-10 concentrations. The reduction in dietary CP level decreased (p < 0.05) serum urea nitrogen concentrations, isoleucine, serine and proline concentrations, but increased serum arginine concentrations. Few interactions between keratinase supplementation and dietary CP concentration were observed. This study indicated that dietary keratinase supplementation improved apparent ileal amino acid digestibility for growing pigs and had a positive effect on weight gain, immune response and loin muscle area for nursery pigs.     

Folate and homocysteine metabolism in copper-deficient rats.

To investigate the effect of copper deficiency on folate and homocysteine metabolism, we measured plasma, red-cell and hepatic folate, plasma homocysteine and vitamin B-12 concentrations, and hepatic methionine synthase activities in rats. Two groups of male Sprague-Dawley rats were fed semi-purified diets containing either 0. 1 mg (copper-deficient group) or 9.2 mg (control group) of copper per kg. After 6 weeks of dietary treatment, copper deficiency was established as evidenced by markedly decreased plasma and hepatic copper concentrations in rats fed the low-copper diet. Plasma, red-cell, hepatic folate, and plasma vitamin B-12 concentrations were similar in both groups, whereas plasma homocysteine concentrations in the copper-deficient group were significantly higher than in the control group (P<0.05). Copper deficiency resulted in a 21% reduction in hepatic methionine synthase activity as compared to the control group (P<0.01). This change most likely caused the increased hepatic 5-methyltetrahydrofolate and plasma homocysteine concentrations in the copper-deficient group. Our results indicate that hepatic methionine synthase may be a cuproenzyme, and plasma homocysteine concentrations are influenced by copper nutriture in rats. These data support the concept that copper deficiency can be a risk factor for cardiovascular disease.     

Effects of supplementation with vitamin E on the performance and the tissue peroxidation of broiler chicks and the stability of thigh meat against oxidative deterioration

Two experiments were conducted: Expt 1 determined the optimal allowance of vitamin E in the diet for broiler chicks aged 0–3 weeks; Expt 2 investigated the effects of different dietary levels of vitamin E (α-tocopherol) on the performance and the oxidative stability of thigh meat of broiler chicks during storage. In Expt 1, 1-day-old 900 broiler chicks were allocated to five treatments, each with six replicates (cages) of 22 as-hatched chicks for performance evaluation, and another cage of 45 male chicks for determining plasma and hepatic α-tocopherol and thiobarbituric acid reactive substances (TBARS) concentration in blood and liver. The basal dietary α-tocopherol concentration was 13 mg/kg, and the five α-tocopherol acetate supplementation levels were 0, 5, 10, 50 and 100 mg/kg. For 0–3-week-old broiler chicks fed with maize–soya bean meal–soya oil type diet, supplementation of vitamin E did not influence the feed intake, but tended to improve growth and feed utilization, however there was no significant correlation between performance and vitamin E supplementation level. Significant positive correlations existed between dietary supplemental vitamin E level and plasma or hepatic α-tocopherol concentrations (P<0.05), and a negative correlation with hepatic TBARS levels no matter at what age (11, 16 and 21 days). In Expt 2, 2200 broiler chicks were randomly allocated to five treatments with four replicates (pens) in each. Chicks were fed ad libitum five pellet diets supplemented with vitamin E at 5, 10, 20, 50 and 100 mg/kg of diet, respectively. The basal dietary α-tocopherol level of grower and finisher diets were 7 and 6 mg/kg, respectively. Supplementation of vitamin E tended to improve growth and feed utilization of birds during 0–3 weeks of age, but the performance from 0 to 6 weeks of age were not influenced. The hepatic α-tocopherol concentrations of 6-week-old chicks linearly increased with the dietary vitamin E levels (R²=0.98, P<0.001). The content of TBARS in the thigh meat over 4 days of storage under 4°C was significantly decreased by increasing dietary vitamin E level (P<0.05). There was a significant inverse relationship between TBARS value in the thigh meat and the dietary vitamin E level (R²=0.93, P<0.01). Supplementation of vitamin E significantly improved the meat quality stability substantially against oxidative deterioration. Comparing the hepatic α-tocopherol levels of chicks in Expts 1 and 2, total allowance of dietary α-tocopherol of 20–30 mg/kg could sustain relatively constant hepatic α-tocopherol level at round about 2–2.5 μg/kg.     

Glutathione Peroxidase Activity and Erythrocyte Lipid Peroxidation as Indices of Selenium and Vitamin E Status in Young Pigs

A randomized, blocked 23 factorial experiment was conducted with 48 pigs from sows fed a diet low in selenium and vitamin E. From 3 to 12 weeks of age the piglets were kept in single pens and fed a basic diet consisting mostly of barley, dried skim milk, soybean meal and dried yeast, and containing 55 µg selenium and 3 mg vitamin E per kg. The treatment factors — i.e. feed supplements — were 2 levels of Se (nil, 60 µg/kg), 2 levels of vitamin E (nil, 50 mg/kg), and 2 levels of the feed antioxidant ethoxyquin (nil, 150 mg/kg). Blood samples, collected at termination of the experiment, were examined for glutathione peroxidase activity (GSH-Px) and resistance against erythrocyte lipid peroxidation (ELP) to evaluate Se and vitamin E status, respectively. Analysis of variance showed the GSH-Px activity to be litter-dependent (P < 0.001) and influenced by selenium supplementation (P < 0.001) but not by the other supplements or by interactions between supplements. Resistance against ELP was influenced only by vitamin E supplementation (P < 0.001). GSH-Px and ELP thus seem to be valuable and simple methods for evaluating, respectively, Se status and vitamin E status in growing pigs.     

Effects of dietary protein and amino acid levels on the expression of selected cationic amino acid transporters and serum amino acid concentration in growing pigs

The absorption of lysine is facilitated by leucine, but there is no information regarding the effect of crude protein, lysine and leucine levels on the expression of cationic amino acid transporters in pigs. Therefore, an experiment was conducted with 20 pigs (14.9 +/- 0.62 kg initial body weight) to evaluate the effect of two protein levels, and the content of lysine, threonine, methionine and leucine in low crude protein diets on the expression of b(0,+) and CAT-1 mRNA in jejunum, Longissimus dorsi and Semitendinosus muscles and serum concentration of amino acids. Treatments were as follows: (i) wheat-soybean meal diet, 20% crude protein (Control); (ii) wheat diet deficient in lysine, threonine and methionine (Basal diet); (iii) Basal diet plus 0.70% L-lysine, 0.27% L-threonine, 0.10% DL-methionine (Diet LTM); (iv) Diet LTM plus 0.80% L-leucine (Diet LTM + Leu). Despite the Basal diet, all diets were formulated to meet the requirements of lysine, threonine and methionine; Diet LTM + Leu supplied 60% excess of leucine. The addition of lysine, threonine and methionine in Diet LTM increased the expression of b(0,+) in jejunum and CAT-1 in the Semitendinosus and Longissiums muscles and decreased CAT-1 in jejunum; the serum concentration of lysine was also increased (p < 0.01). Further addition of L-leucine (Diet LTM + Leu) decreased the b(0,+) expression in jejunum and CAT-1 in the Longissimus dorsi muscle (p < 0.05), increased the serum concentration ofleucine and arginine and decreased the concentration of isoleucine (p < 0.05). Pigs fed the Control diet expressed less b(0,+) in jejunum, and CAT-1 in the Semitendinosus and Longissiums muscles expressed more CAT-1 in jejunum (p < 0.05) and had lower serum concentration ofisoleucine, leucine and valine (p < 0.05), but higher lysine concentrations (p < 0.01) than those fed Diet LTM. These results indicated that both, the level and the source of dietary amino acids, affect the expression of cationic amino acid transporters in pigs fed wheat-based diets.     

Oxidative stress biomarker monitoring in elite women volleyball athletes during a 6-week training period

The objectives of this study were to determine (a) if reactive oxygen metabolites (ROMs) are a reliable parameter for monitoring oxidative stress in athletes alone or in association with other parameters of oxidative stress and depending on whether antioxidant supplements are taken or not; (b) the level of oxidative stress in athletes before the competition season; and (c) if oxidative status could be improved in volleyball athletes. Sixteen women athletes (supplemented group) received an antioxidant cocktail containing vitamin E, vitamin C, zinc gluconate, and selenium as a dietary supplement during a 6-week training period, whereas 12 of them (control group) received no dietary supplement. Blood samples were taken before and after the training period. The following parameters were measured: ROMs, superoxide anion (O2??), malondialdehyde (MDA), advanced oxidation protein products (AOPP), lipid hydroperoxide (LOOH), biological antioxidative potential (BAP), paraoxonase activity toward paraoxon (POase) and diazoxon (DZOase), superoxide dismutase(SOD), total sulfydryl group concentration (SH groups), and lipid status. Reactive oxygen metabolites were taken as the dependent variable and MDA, O2??, AOPP, and LOOH as independent variables. In the group of athletes who have received supplementation, linear regression analysis revealed that the implemented model had a lower influence on dROMs (70.4 vs. 27.9%) after the training period. The general linear model showed significant differences between parameters before and after training/supplementation (Wilks' lambda = 0.074, F = 11.76, p < 0.01). At the partial level, significant increases in ROM levels (p <0.05, 95% confidence interval [CI]: 286-337), SOD activity (CI: 113-144), and BAP (CI: 2,388-2,580) (p < 0.01) were observed. The association between ROMs and other parameters of oxidative stress was reduced in athletes who received supplements. During the precompetition training period, treatment with dietary supplements prevented the depletion of antioxidative defense in volleyball athletes.     

Carcass composition and meat quality of indigenous Yanan pigs of China

The Yanan (YN) pig is a traditional Chinese indigenous breed that is raised in southwest China in the Sichuan Province, but there is little data on the germplasm characteristics of this breed. To evaluate carcass characteristics and meat quality of the YN pig, we compared carcass and meat quality of YN pigs and Landrace × Yanan (CY) hybrid pigs; 30 YN pigs and 30 CY pigs weighing 20 ± 2 kg were reared and slaughtered at the normal slaughter weight (100-120 kg). The carcasses were chilled and the left carcass side was dissected into bone, lean meat, fat, and skin; meat quality parameters were measured. Carcasses of YN pigs were lighter (88.85 vs 90.05 kg, P < 0.05) and shorter (71.88 vs 77.61 cm, P < 0.001); they contained less lean meat (41.60 vs 49.25%, P < 0.001), less ham and breech (25.93 vs 27.53%, P < 0.001) and less carcass bone (9.83 vs 10.53%, P < 0.01) than did carcasses of CY pigs. On the other hand, YN pigs had more carcass subcutaneous fat and skin (48.58 vs 40.23%, P < 0.001), thicker backfat (3.67 vs 3.43 cm, P < 0.001) and smaller loin muscle area (9.83 vs 26.91 cm(2), P < 0.001) compared with CY pigs. Among meat quality parameters, YN pigs had higher pH(1) (6.41 vs 6.17, P < 0.001), higher color score(u) (3.86 vs 3.36, P < 0.001) and lower Minolta L(u) values (40.89 vs 45.32, P < 0.01) than CY pigs. On the other hand, YN pigs had lower drip loss (1.31 vs 2.26%, P < 0.05) and lesser fiber area (2351.34 vs 3025.43 μm(2), P < 0.01) than CY pigs. Both breeds had high intramuscular fat (4.46% in YN and 4.45% in CY). No significant differences in other carcass traits and meat quality were found in the two populations. We conclude that YN pigs could be used in commercial pig production to provide good tasting and high-quality niche products.     

Dysregulated Hepatic Methionine Metabolism Drives Homocysteine Elevation in Diet-Induced Nonalcoholic Fatty Liver Disease

Methionine metabolism plays a central role in methylation reactions, production of glutathione and methylarginines, and modulating homocysteine levels. The mechanisms by which these are affected in NAFLD are not fully understood. The aim is to perform a metabolomic, molecular and epigenetic analyses of hepatic methionine metabolism in diet-induced NAFLD. Female 129S1/SvlmJ;C57Bl/6J mice were fed a chow (n = 6) or high-fat high-cholesterol (HFHC) diet (n = 8) for 52 weeks. Metabolomic study, enzymatic expression and DNA methylation analyses were performed. HFHC diet led to weight gain, marked steatosis and extensive fibrosis. In the methionine cycle, hepatic methionine was depleted (30%, p< 0.01) while s-adenosylmethionine (SAM)/methionine ratio (p< 0.05), s-adenosylhomocysteine (SAH) (35%, p< 0.01) and homocysteine (25%, p< 0.01) were increased significantly. SAH hydrolase protein levels decreased significantly (p <0.01). Serine, a substrate for both homocysteine remethylation and transsulfuration, was depleted (45%, p< 0.01). In the transsulfuration pathway, cystathionine and cysteine trended upward while glutathione decreased significantly (p< 0.05). In the transmethylation pathway, levels of glycine N-methyltransferase (GNMT), the most abundant methyltransferase in the liver, decreased. The phosphatidylcholine (PC)/ phosphatidylethanolamine (PE) ratio increased significantly (p< 0.01), indicative of increased phosphatidylethanolamine methyltransferase (PEMT) activity. The protein levels of protein arginine methytransferase 1 (PRMT1) increased significantly, but its products, monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA), decreased significantly. Circulating ADMA increased and approached significance (p< 0.06). Protein expression of methionine adenosyltransferase 1A, cystathionine β-synthase, γ-glutamylcysteine synthetase, betaine-homocysteine methyltransferase, and methionine synthase remained unchanged. Although gene expression of the DNA methyltransferase Dnmt3a decreased, the global DNA methylation was unaltered. Among individual genes, only HMG-CoA reductase (Hmgcr) was hypermethylated, and no methylation changes were observed in fatty acid synthase (Fasn), nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (Nfκb1), c-Jun, B-cell lymphoma 2 (Bcl-2) and Caspase 3. NAFLD was associated with hepatic methionine deficiency and homocysteine elevation, resulting mainly from impaired homocysteine remethylation, and aberrancy in methyltransferase reactions. Despite increased PRMT1 expression, hepatic ADMA was depleted while circulating ADMA was increased, suggesting increased export to circulation.     

Betaine or folate can equally furnish remethylation to methionine and increase transmethylation in methionine-restricted neonates

Methionine partitioning between protein turnover and a considerable pool of transmethylation precursors is a critical process in the neonate. Transmethylation yields homocysteine, which is either oxidized to cysteine (i.e., transsulfuration), or is remethylated to methionine by folate- or betaine- (from choline) mediated remethylation pathways. The present investigation quantifies the individual and synergistic importance of folate and betaine for methionine partitioning in neonates. To minimize whole body remethylation, 4–8-d-old piglets were orally fed an otherwise complete diet without remethylation precursors folate, betaine and choline (i.e. methyl-deplete, MD-) (n=18). Dietary methionine was reduced from 0.3 to 0.2 g/(kg∙d) on day-5 to limit methionine availability, and methionine kinetics were assessed during a gastric infusion of [¹³C₁]methionine and [²H₃-methyl]methionine. Methionine kinetics were reevaluated 2 d after pigs were rescued with either dietary folate (38 μg/(kg∙d)) (MD + F) (n=6), betaine (235 mg/(kg∙d)) (MD + B) (n=6) or folate and betaine (MD + FB) (n=6). Plasma choline, betaine, dimethylglycine (DMG), folate and cysteine were all diminished or undetectable after 7 d of methyl restriction (P<.05). Post-rescue, plasma betaine and folate concentrations responded to their provision, and homocysteine and glycine concentrations were lower (P<.05). Post-rescue, remethylation and transmethylation rates were~70–80% higher (P<.05), and protein breakdown was spared by 27% (P<.05). However, rescue did not affect transsulfuration (oxidation), plasma methionine, protein synthesis or protein deposition (P>.05). There were no differences among rescue treatments; thus betaine was as effective as folate at furnishing remethylation. Supplemental betaine or folate can furnish the transmethylation requirement during acute protein restriction in the neonate.     

In vitro penetration of fresh and vitrified swine oocytes by homologous spermatozoa using different incubation systems

The present study consisted of two experiments. In the first one, ejaculates from four boars were used to compare in vitro penetration (IVP) rates of fresh and vitrified swine oocytes by homologous spermatozoa in four treatments: fresh oocytes in conventional incubation (CO2 incubator) (FC), vitrified oocytes in conventional incubation (VC), fresh oocytes in submarine (bag) incubation (FS) and vitrified oocytes in submarine incubation (VS). The IVP rates for FC, VC, FS and VS were 46.5, 44.3, 36.9 and 33.1%, respectively. Analysis through Chi-square tests identified no differences in IVP rates between FC and VC and between FS and VS (P > 0.05), but IVP rate for FC was greater (P < 0.05) than those for both FS and VS. Besides IVP rate for VC did not differ (P > 0.05) from those for FC and FS, but it was greater than that for VS (P < 0.05). Logistic regression analysis identified differential effects of treatments dependant on individual boars. The second experiment evaluated the influence of semen storage period on the semen quality of the two boars associated with greater IVP rate in the first experiment. Semen quality was estimated by IVP rate using the VC treatment and by the following methods: sperm motility, sperm morphology, hypoosmotic swelling test (HOST) and thermal stress test (TST). According to analysis using Chi-square tests, IVP rate did not differ (P > 0.05), for the first boar, between 0 (100.0%) and 24 h of semen storage (98.1%) nor after 48 and 72 h (66.0 and 59.3%, respectively), but IVP rates were greater during the 0-24 h period compared with the 48-72 h period (P < 0.05). For the second boar, IVP rate at 0 h (50.6%) was greater (P < 0.05) than at 24, 48 and 72 h of semen storage (34.3, 28.3 and 24.0%, respectively), with no further differences observed after 24 h (P > 0.05). Logistic regression analysis identified that the effect of storage on IVP rate was influenced by the effect of individual boars. No differences in semen quality during the storage period were identified by conventional methods of semen evaluation, for either boar (P > 0.05) using analysis of variance with repeated measures. These results indicate that IVP test can be used to estimate boar fertility, even when vitrified oocytes are used (if using conventional CO2 incubators) or using an alternative submarine incubation system (if using fresh oocytes). The IVP test was the only method of semen evaluation that identified the reduction in semen quality up to 72 h of storage.