Caffeic acid, naringenin and quercetin enhance glucose-stimulated insulin secretion and glucose sensitivity in INS-1E cells.

AIMS: Caffeic acid, naringenin and quercetin are naturally occurring phenolic compounds (PCs) present in many plants as secondary metabolites. The aim of this study was to investigate their effect on glucose-stimulated insulin secretion (GSIS) in INS-1E cells and to explore their effect on expression of genes involved in ß-cell survival and function under normoglycaemic and glucotoxic conditions. METHODS: For acute studies, INS-1E cells were grown in 11 mM glucose (72 h) and then incubated with the PCs (1 h) with 3.3/16.7 mM glucose; whereas, for chronic studies, the cells were grown in 11 mM glucose (72 h) with/without the PCs, and then incubated with 3.3/16.7 mM glucose (1 h); thereafter, GSIS was measured. For GSIS and gene expression studies (GES) under glucotoxic conditions, two sets of cells were grown in 11/25 mM glucose with/without the PCs (72 h): one was used for GES, using real time RT-PCR, and the other was exposed to 3.3/16.7 mM glucose, followed by measurement of GSIS. RESULTS: The study demonstrated that the PCs can enhance GSIS under hyperglycaemic and glucotoxic conditions in INS-1E cells. Moreover, these compounds can differentially, yet distinctly change the expression profile of genes [Glut2 (glucose transporter 2), Gck (glucokinase), Ins1 (insulin 1), Ins2, Beta2 (neurogenic differentiation protein 1), Pdx1 (pancreatic and duodenal homeobox protein 1), Akt1 (RAC-α serine/threonine-protein kinase encoding gene), Akt2 (RAC-ß serine/threonine-protein kinase encoding gene), Irs1 (insulin receptor substrate 1), Acc1 (acetyl CoA carboxylase 1), Bcl2 (ß-cell lymphoma 2 protein), Bax (Bcl-2 associated X protein), Casp3 (Caspase 3), Hsp70 (heat shock protein 70), and Hsp90] involved in ß-cell stress, survival and function. CONCLUSION: The results indicate that the PCs tested enhance GSIS and glucose sensitivity in INS-1E cells. They also modulate gene expression profiles to improve ß-cell survival and function during glucotoxicity.

Validation of biomarkers for loin meat quality (M. longissimus) of pigs.

The aim of this study was to validate previously reported associations between microarray gene expression levels and pork quality traits using real-time PCR. Meat samples and meat quality data from 100 pigs were collected from a different pig breed to the one tested by microarray (Large White versus Pietrain) and a different country of origin (Denmark versus Germany). Ten genes (CARP, MB, CSRP3, TNNC1, VAPB, TNNI1, HSPB1, TNNT1, TIMP-1, RAD-like) were chosen from the original microarray study on the basis of the association between gene expression levels and the meat quality traits meat %, back fat, pH24, drip loss %, colour a*, colour b*, colour L*, WB-SF, SFA, MUFA, PUFA. Real-time PCR detection methods were developed for validation of all ten genes, confirming association with drip loss (two of two genes), ultimate pH (three of four genes), a* (redness) (two of six genes) and L*(lightness) (two of four genes). Furthermore, several new correlations for MUFA and PUFA were established due to additional meat quality trait information on fatty acid composition not available for the microarray study. Regression studies showed that the maximum explanation of the phenotypic variance of the meat quality traits was 50% for the ultimate pH trait using these ten genes only. Additional studies showed that the gene expression of several of the genes was correlated with each other. We conclude that the genes initially selected from the microarray study were robust, explaining variances of the genes for the meat quality traits.

Anti-CD20 antibody therapy and risk of infection in patients with demyelinating diseases.

BACKGROUND: Anti-CD20 antibody therapy may be associated with an increased risk of infections. We therefore investigated risk factors for infection in patients with demyelinating diseases treated with anti-CD20 antibody therapy. METHODS: In this retrospective uncontrolled study, patients ever treated with anti-CD20 antibodies at an academic clinic were identified through the Danish Multiple Sclerosis Registry (DMSR). Data were collected from medical charts and the DMSR. We assessed occurrence of severe infections (requiring hospitalization), varicella zoster virus (VZV), major comorbidities and routine laboratory values for lymphocytes, IgG and IgM. RESULTS: A total of 447 patients ever treated with anti-CD20 antibody therapy were identified; of these 416 with 649 patient years of follow-up were still under therapy. In this group, seven patients had VZV infections, and 16 patients had been hospitalized with infections during up to three years of follow-up on anti-CD20 therapy. Comorbidity was recorded in 80 patients. The risk of severe infection was associated with comorbidities, higher age, longer duration of treatment, and higher Expanded Disability Status Scale (EDSS) scores. In multivariable analyses treatment duration, EDSS scores and presence of comorbidity were independently associated with risk of severe infections. Serum concentrations of IgG and IgM decreased with increasing duration of therapy but were not associated with risk of severe infections. Patients with VZV infection had lower lymphocyte counts and lower serum concentrations of IgM. In multivariable analyses only lymphocyte counts were independently associated with risk of VZV infection. CONCLUSIONS: In this retrospective study of patients treated with anti-CD20 antibodies, the risk of infections requiring hospitalization was independently associated with comorbidities, duration of treatment, and higher EDSS scores. Risk of VZV infection was independently associated with lymphopenia. Future studies investigating strategies for mitigating risk of infection in patients treated with anti-CD20 antibodies are warranted, especially for older patients, patients with higher levels of disability and for patients with a longer duration of treatment.

Rest before slaughter ameliorates pre-slaughter stress-induced increased drip loss but not stress-induced increase in the toughness of pork.

One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1-3h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs.

Effects of fasting prior to slaughter on technological and sensory properties of the loin muscle (M. longissimus dorsi) of pigs.

The aim of this study was to investigate the effect of pre-slaughter fasting time, sex and feeding regime on water-holding capacity (WHC), colour and sensory properties and their relationship with pH in M. longissimusdorsi (LD) in pigs. 270 pigs of the commercial Norwegian crossbreed Noroc (Norwegian Landrace×Yorkshire sow and Norwegian Landrace×Duroc boar) were used involving two sexes (gilts and castrates), two feeding regimes (restricted and ad libitum) and four fasting treatments: (F4) 4h fasting (control), (F175) 17.5h fasting on the farm, (FO175) 17.5h fasting overnight at the abattoir, and (FO265) 26.5h fasting overnight at the abattoir. Additionally, the pigs experienced two abattoir lairage times as fasting treatments F4 and F175had a lairage time of 1.5 h, while fasting treatments FO175 and FO265 had a lairage time of 23.0h. A short fasting time of 4h led to a delayed decline in pH post-mortem and a lower ultimate pH (pHu) in the LD compared with a fasting time of 26.5h which resulted in a rapid pH decline early post-mortem and a high pHu. Prolonged fasting reduced drip loss, resulted in a darker colour and tended to improve tenderness of the LD. Castrates showed lower drip loss, higher lightness and improved tenderness and juiciness compared with gilts, while ad libitum feeding improved tenderness compared to restricted feeding. There are obvious negative relationships between pHu and drip loss, lightness and tenderness of LD.

Temporal changes in glycogenolytic enzyme mRNAs during myogenesis of primary porcine satellite cells.

The objective was to study the regulation of glycogenolytic enzyme mRNAs in porcine satellite cells during proliferation and differentiation. Beyond 80% confluence, cells were grown in absence or presence of 1µM insulin. The observed increases in abundance of mRNA for glycogenin, glycogen synthase, phosphorylase kinase, phosphorylase and glycogen debranching enzyme, and no alterations of the transporter molecule GLUT4, clearly indicate that glycogenolytic enzymes of potential importance to meat quality development are regulated at the gene level during myogenesis, and are heavily involved in muscle cell and muscle fibre development. The genes, however, are not influenced by insulin, and the lack of response to insulin of expression of gene-encoding enzymes involved in the formation and degradation of glycogen may question the applicability of porcine cell culture systems, like the one applied, as a model to study the regulation and regulatory mechanism of energy metabolism in muscles.

Novel method for determination of myofibril fragmentation post-mortem.

Multi angle light scattering was used to determine the myofibril fragmentation of pig longissimus dorsi muscle which was then compared with results from the common turbidity method. The method is based on measurement of the myofibril particle size distribution with the use of a special optical unit containing several individual detectors. The method was able to determine post-mortem changes in a pig muscle homogenate without purification of the myofibrils and is therefore simpler and much faster than the traditional turbidity method. There was a significant correlation (p<0.01) between Warner-Bratzler shear force (WBSF) and particle size distribution. The root mean square error of prediction was found to be 6.1N (10-15% of the measured WBSF) when multivariate data analysis was used to make a prediction model for WBSF. Multi angle light scattering is very useful for estimation of myofibril fragmentation since the method is fast and the sample preparation is simple.

In vitro and in vivo studies of creatine monohydrate supplementation to Duroc and Landrace pigs.

Duroc and Landrace pigs as well as primary myotubes from these breeds were used to investigate mechanisms behind differences in their response to creatine monohydrate (CMH). Pigs were supplemented with 0, 12.5, 25 or 50g CMH/d for 5 days (n=10 per treatment and breed). Plasma levels of creatine increased dose-dependently in both breeds, while muscle-creatine phosphate content increased only in the Duroc pigs. (1)H NMR metabolic profiling showed a tendency towards clustering according to CMH supplementation only among Duroc pigs, revealing a stronger response compared to Landrace pigs. The abundance of insulin-like growth factor I and myostatin mRNA was decreased by CMH supplementation while that of type 1 IGF-receptor and creatine transporter was unaffected. Protein synthesis, increased in the myotubes from both breeds, indicating protein accretion, but no effect was observed on the mRNA abundance of IGF-I, type 1 IGF-receptor, myostatin or the creatine transporter in myotubes.

Mammary nutrient uptake in multiparous sows fed supplementary arginine during gestation and lactation.

Arginine is the precursor for the synthesis of nitric oxide and may increase mammary plasma flow (MPF), which may in turn increase mammary nutrient uptake. Quantifying mammary nutrient uptake improves our understanding of mammary nutrient metabolism and may potentially allow identification of limiting nutrients for colostrum and milk production. Thus, the objectives of the present study were 1) to study the impact of 25 g/d of crystalline Arg (ARG) on MPF and uptake of nutrients by the mammary glands compared with an isonitrogenous supply of Ala (51 g/d; control [CON]) fed to a total of 8 sows from d 30 of gestation until weaning on d 28 of lactation and 2) to quantify mammary nutrient uptake in late gestation and in early and at peak lactation. Sows were surgically fitted with indwelling catheters on d 76 ± 2 SEM of gestation. -amino hippuric acid (AH) was infused (3.0 mmol/h) in the infusion catheter inserted in the mammary vein, initiated 1 h before the first blood sample at -10, -3, 3, and 17 d in milk (DIM). Blood samples were simultaneously drawn from catheters inserted in the femoral artery and the mammary vein, and the samples were collected in hourly intervals from 0.5 h before to 6.5 h after feeding. Sow milk production was assessed at 3 and 17 DIM. Arterial plasma concentrations of Arg and Ala were increased in ARG and CON sows, respectively ( < 0.01), whereas we did not succeed in detecting a greater MPF in ARG sows ( = 0.30). Arterial-venous differences ( = 0.03) and net mammary flux ( = 0.01) of Ala were increased in CON sows, while the net flux of most other metabolites ( > 0.05) was unaffected by treatment. The mammary extraction of all essential AA was below 13% in late gestation. The average mammary extraction of essential AA at peak lactation was greatest for Leu (51%), while the preprandial extraction was greatest for Lys (57%). The mammary carbon balance (input-output) was negative (-39 ± 12 mol C/d) in early lactation but almost balanced at peak lactation (-13 ± 14 mol C/d), suggesting that mammary fat depots contributed to milk synthesis. In conclusion, we failed to observe an increased MPF and mammary uptake of AA and energy metabolites in ARG-supplemented sows. The mammary extraction rate of essential AA indicated that AA were not limiting for the mammary glands in late gestation, while Lys and Leu appeared to be the 2 most limiting essential AA for milk production at peak lactation.

Supplementing newborn intrauterine growth restricted piglets with a bolus of porcine colostrum raises rectal temperatures one degree Celsius.

Hyperprolific sows have increased litter sizes but also result in more piglets that have been exposed to intrauterine growth restriction (IUGR). These IUGR piglets are likely to have a low rectal temperature and lower blood glucose levels compared with normal piglets at birth. Therefore, we hypothesized that a colostrum bolus at birth and/or heat from an external source would have a positive effect on blood glucose levels, rectal temperatures, and growth up to 8 h postpartum. In addition, liver glycogen and blood values at 8 h were investigated. Eighty-four piglets were classified at birth (time = 0) as IUGR based on their head morphology and randomly allocated to 1 of 4 treatments ( = 21) in a 2 × 2 factorial arrangement: 1) with or without a porcine colostrum bolus (12 mL/kg BW at birth) and 2) with sow or isolated from sow with external heat. Piglets were removed from the sow before they had suckled and were numbered and dried, and initial whole-blood glucose, rectal temperature, and BW were recorded. Piglets in the 2 treatments isolated from sow were placed under a heating lamp (150 W) with a temperature range of 35 to 39°C. Rectal temperatures, glucose, and BW were measured again at 1, 2, 4, 6, and 8 h after birth, and a final plasma sample and organs (liver and brain) were removed at 8 h. There was a time × colostrum bolus interaction ( = 0.026) and a time × sow interaction ( < 0.001) for whole-blood glucose. The piglets that were given a bolus had greater glucose levels after 1 h postpartum (time = 1 h) than piglets without a bolus at birth, but from time = 2 h and onward, there was no difference ( > 0.05). There was a time × colostrum bolus interaction ( < 0.001) and a time × sow interaction ( < 0.001) on rectal temperatures. One hour after birth, the piglets with a bolus had a greater rectal temperature compared with piglets without a bolus (37.5 vs. 36.6°C; < 0.001) and the piglets that had been isolated from the sow had a greater rectal temperature compared with the 2 treatments with sows (37.8 vs. 36.3°C; < 0.001). Four hours after birth, rectal temperature was not affected by treatments. In conclusion, both heat and a colostrum bolus increased rectal temperature by 1°C an hour after birth. However, after 4 h, no differences were found between the treatments. Interventions to help IUGR piglets postpartum most likely need to be frequent to have any effect on whole-blood glucose, rectal temperatures, and BW over the first 8 h.

Changes in proteolytic enzyme mRNAs relevant for meat quality during myogenesis of primary porcine satellite cells.

The objective was to study the regulation of proteolytic enzyme mRNA's in porcine satellite cells during proliferation and differentiation. Beyond 80% confluence, cells were grown in absence or presence of 1µM insulin. The temporal changes in transcription of micro molar-, milli molar- and muscle specific calpains (p94), calpastatin and caspase 3 in response to insulin was evaluated and myogenin transcription and creatine kinase activity was determined to indicate differentiation. The housekeeping genes (GAPDH and ß-actin) were slightly affected by developmental stage and transiently by the insulin treatment but this did not affect the conclusions. The mRNA abundance of micro molar calpain, p94 and calpastatin increased from proliferation to differentiation. Milli molar calpain- and caspase 3-transcriptions were up-regulated in two steps, suggesting these two enzymes are involved in two distinct processes. Insulin stimulated differentiation as indicated by elevated creatine kinase activity but did not affect myogenin transcription. Insulin down-regulated milli molar calpain and calpastatin transcription and tended to down-regulate caspase 3 transcription but did not affect p94 or micro molar calpain. In conclusion, proteolytic enzymes relevant for post-mortem tenderisation are regulated at the gene level during myogenesis, indicating they are involved in muscle cell and muscle fibre development. Thus, a porcine satellite cell culture may be a model system to study regulation and relative contribution to proteolysis by the calpains.

Dietary creatine monohydrate affects quality attributes of Duroc but not Landrace pork.

Increased creatine content in the muscle may delay post mortem lactate formation and postpone the pH decline, hence potentially improving the water-holding capacity (WHC). Duroc and Landrace pigs were supplemented with 0, 12.5, 25 or 50g creatine monohydrate (CMH)/d for 5 days prior to slaughter. Meat from Longissimus dorsi (LD) of Duroc pigs had a higher WHC and pH at all times, lower colour determinants; a* (redness), b* (yellowness), L* (lightness) and was more juicy compared to that of Landrace pigs. Furthermore, higher pH(2h), pH(24h) and decreased colour determinants were observed in carcass sides exposed to a faster cooling profile. Dietary supplementation with CMH increased the body weight gain of both breeds. However, only meat from Duroc pigs had higher pH(30min) and pH(45min) (at 50g CMH/d) and WHC, but reduced redness (reduced in both breeds) and juiciness when supplemented with CMH compared to non-supplemented controls.

The effect of epidermal growth factor on circulating levels of IGF and IGF-binding proteins in adult Goettingen minipigs.

It has recently been demonstrated that epidermal growth factor (EGF) administration to neonatal rodents causes growth retardation with concomitant reductions in circulation levels of IGF-I. We describe the effects of systemic EGF administration for 4 weeks on circulating levels of IGF-I and IGF-binding proteins (IGFBPs) and on thyroid hormones (tri-iodothyronine, T3; thyroxine, T4) in sexually mature pigs. Goettingen minipigs of either sex were treated with placebo (n = 5) or EGF (30 micrograms/kg per day, n = 6) s.c. for 4 weeks (in relation to an oesophageal sclerotherapy regimen). Blood samples were taken under anaesthesia before and after 1, 2, 3 and 4 weeks of treatment. Circulating levels of IGF-I, insulin, glucose, T3 and T4 were analysed every week and IGFBPs every second week. IGF-I was not reduced significantly after 1 week but significantly reduced after 2 and 3 weeks of EGF treatment. A similar decline was observed for the major IGFBP, IGFBP-3, which was reduced after 2 and 4 weeks. IGFBP-1, IGFBP-2 and IGFBP-4 increased throughout the treatment period (all significantly at week 4). EGF treatment induced increased circulating T3 after 2, 3 and 4 weeks of EGF treatment. In conclusion, we report that EGF treatment for 4 weeks in Goettingen minipigs reduces circulating IGF-I and IGFBP-3, increases circulating IGFBP-1, IGFBP-2 and IGFBP-4, and induces a slight hyperthyroidism as judged from increased circulating levels of T3.

Dietary salbutamol and level of protein: effects on the acute stress response in pigs.

Effect on the acute stress response of dietary inclusion of 3 ppm salbutamol (beta-2-adrenergic agonist) at two levels of protein were investigated in growing pigs (from 25 kg live weight). The trial comprised six litters (blocks) of four females allocated randomly to four treatment groups in accordance with a 2 x 2 factorial arrangement. The response to an open-field test and to an intruder were measured at 50 kg live weight. Salbutamol increased immobility and looking, reduced total exploration, and increased plasma ACTH after test. At high dietary levels of protein, salbutamol also increased the latency to attack. High dietary levels of protein reduced standing still, latency to contact a novel object and an intruder, and level of plasma cortisol before test. Moreover, high protein without salbutamol seemed to reduce the latency to attack an intruder. In conclusion, chronic treatment with salbutamol shifted the acute stress response in pigs toward a passive response, whereas high dietary level of protein provoked an active response, which may have consequences in pig production.

Objectivity of two methods of differentiating fibre types and repeatability of measurements by application of the TEMA image analysis system.

The objectivity of two of the most widely used methods for differentiation of fibre types, i.e. 1) the myosin ATP-ase method (Brooke and Kaiser, 1970a,b) and 2) the combined method, by which the myosin ATP-ase reaction is used to differentiate between fast and slow twitch fibres and NADH-tetrazolium reductase activity is used to identify the subgroups of fast twitch fibres (Ashmore and Doerr, 1970, Peter et al., 1972), was assessed in muscle samples from horses, calves and pigs. We also assessed the objectivity of the alpha-amylase-PAS preparation for the visualisation of capillaries (Andersen, 1975) in these species. For the purpose of reducing the time costs of histochemical analysis of muscle samples, we have developed an interactive image analysis system which is described. All analyses are performed on this system. In accordance with several other investigations, differences between the two methods of differentiating fibre types were found only for the relative distribution of the fast-twitch fibre subgroups (p < 0.02 and p < 0.05 for the relative number of type IIA and IIB, respectively) whereas when calculated in relative area, only the proportion of type IIA fibres differed significantly (p < 0.05). Significant interaction effects between method and person and method and species were found for the same traits. When methods were analysed separately, the combined method displayed a significant variance component of person for the distribution of type IIA fibres both in relative number and in relative area (p < 0.01 and p < 0.001, respectively). The objectivity of the ATP-ase method was further substantiated by the fact that a higher fraction of the total variance for the relative area distribution of type IIA fibres was explained by the statistical model (72.1% versus 34.2% for the combined method). Although the repeatability of measurements between persons was generally high (> 87%), the impact of differences in pre-requisites (varied degrees of overlap between the fibre types) for performing the differentiation by the combined method raises a question of the reliability of this method. Apparently, no general rules for comparison of results of distribution of the two subgroups of fast twitch fibres by the two methods are applicable. The alpha-amylase-PAS method was found to be a fairly objective method to identify capillaries in muscles from horses, calves and pigs. However, as capillarity described in combination with other traits to give an indication of diffusion characteristics is significantly influenced by person, it is recommended that the same person perform all the analysis of a project. In addition to the methodological results in this study, we have shown that by application of the TEMA image analysis system, which is more rapid compared with the time-consuming traditional method for evaluation of histochemical preparations, analysis of samples from large-scale experiments are now possible.

Within-litter variation in muscle fiber characteristics, pig performance, and meat quality traits.

The objective of this study was to examine the intralitter variation in postnatal growth performance, meat quality, and muscle fiber characteristics when littermates were categorized by carcass weight. Thirty-nine litters were weaned at 4 wk of age and had free access to feed from 2 wk of age until slaughter. They were slaughtered by litter at an average BW of 104 +/- 14 kg, and six pigs per litter were selected for analysis: the heaviest- (HW), middle- (MW), and lightest-weight (LW) pig of each sex. Categorizing littermates in LW, MW, and HW pigs at the same age reflected the differences in postnatal growth rate within a litter; thus ADG, muscle mass, and muscle deposition rate differed across pig weight groups (P < 0.001). Also, the total DNA content was different among pig weight groups (P < 0.001) and reflected differences in muscle growth rate. The difference in muscle growth rate between LW and MW pigs could be explained by a larger (P < 0.05) mean fiber area (MFA) in MW pigs, whereas the number of muscle fibers was similar. Growth rate differences between MW and HW pigs could in part be explained by a higher number (P < 0.01) of equal-sized muscle fibers in HW pigs. The difference in MFA was due to a higher estimated DNA and RNA content per muscle fiber in MW and HW compared with LW pigs (P < 0.05). Pigment content was higher in MW and HW compared with LW pigs (P < 0.01), but no other measured meat quality traits were significantly different across pig weight groups. These results indicate that both the number and the growth rate of muscle fibers contribute to intralitter variation in postnatal growth performance.

The effect of cimaterol on muscle fiber characteristics, capillary supply, and metabolic potentials of longissimus and semitendinosus muscles from young Friesian bulls.

The objective of this study was to determine the effect of the beta-adrenergic agonist cimaterol (CIM) on fiber characteristics, capillary supply, and metabolic enzyme activities in muscles of young Friesian bulls. Four pairs of monozygotic twins in each of three live weight groups (WG) were used (initial average live weight [LW]: 162, 299, and 407 kg, respectively). Within each pair, one twin was fed .06 mg of CIM.kg LW-1.d-1 for 90 d. The other twin served as control (C). Needle biopsies were obtained from the longissimus (LM) and semitendinosus (ST) muscles at d 82 to 84 of treatment, and muscle fibers were identified as slow-twitch (Type I) or fast-twitch (Type IIA or Type IIB) by the myosin ATPase stain. In LM, the proportion of Type I (C: 24.0%, CIM: 20.4%; P < .07) and Type IIA fibers (C: 24.2%, CIM: 8.6%; P < .001) decreased, whereas the proportion of Type IIB fibers increased (C: 51.7%, CIM: 71.1%; P < .001). Cimaterol increased the cross-sectional area of Type I (P < .02) and Type IIB fibers (P < .001), with no change in Type IIA fibers. Overall, the mean fiber area increased (C: 2,363 microns 2, CIM: 3,934 microns 2; P < .001). The number of capillaries per fiber did not change, but the number of capillaries per square millimeter decreased (P < .001) after CIM treatment. Cimaterol changed metabolic enzyme activities toward lower oxidative capacity of the muscle (lactate dehydrogenase: +22%, hydroxyacyl-CoA dehydrogenase: -33%, and citrate synthetase: -34%; all P < .001) and reduced the glycogen content by 25% (P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased maternal nutrition of sows has no beneficial effects on muscle fiber number or postnatal growth and has no impact on the meat quality of the offspring.

The objective of this study was to examine how increased feed intake of the sow during early to mid-gestation affects sow performance and the muscle fiber number, performance, and technological meat quality of the offspring. Thirty-nine pregnant sows (Landrace x Large White sows mated to Landrace or Large White boars) in their fourth parity were assigned to one of three treatments: 1) the sows were either fed restrictively (control = 15 MJ of NE/d from d 1 to 90, then 24 MJ of NE/d from d 91 to 112, and again 15 MJ of NE/d from d 113 to 115 of gestation); 2) fed ad libitum from d 25 to 50 (A25-50); or 3) ad libitum from d 25 to 70 (A25-70) and as control in the remaining periods. The offspring were weaned at 4 wk of age and had free access to feed from 2 wk of age until slaughter. They were slaughtered litterwise at an average body weight of 104 +/- 14 kg. Estimates for total, primary (P-), and secondary (S-) muscle fiber number; muscle fiber area; and DNA and RNA content were analyzed in semitendinosus muscle (ST) samples from the heaviest, middle, and lightest weight (LW) pigs of each sex within litter selected at slaughter. Technological meat quality traits (pH at 24 h postmortem, drip loss, Minolta color, and pigment) were analyzed in longissimus dorsi muscle. Fiber number, fiber area, and concentrations and content of DNA and RNA of the offspring were not significantly affected by increased maternal nutrition. The ST muscle weight was lower in offspring from A25-50 than control sows (P = 0.019). Average daily gain, carcass weight, and the muscle deposition rate also were numerically lower for A25-50 than control and A25-70 pigs. An interaction between treatment and pig weight was found for muscle deposition rate (P = 0.006), in that LW pigs from treatment A25-50 had a lower deposition rate than LW pigs from control. We found no effect of treatment on the meat quality traits in the offspring. Also, barrows had a higher (P < 0.05) number of P-fibers, higher daily gain, and carcass weight than female pigs. No differences were found on any meat quality traits between sexes. Thus, ad libitum feeding of pregnant sows from d 25 to 50 or d 25 to 70 of gestation did not have any beneficial effect on muscle fiber number and area in the offspring. It seems that maternal ad libitum feeding from d 25 to 50 in gestation had a negative effect on postnatal muscle growth, with especially the LW pigs being affected.

Dietary-induced changes of muscle growth rate in pigs: effects on in vivo and postmortem muscle proteolysis and meat quality.

The effects of various growth rates in pigs induced by four different feeding strategies on the activity of the calpain system and on postmortem (PM) muscle proteolysis and tenderness development were studied. An increased growth rate may be caused by an increased protein turnover, which results in up-regulated levels of proteolytic enzymes in vivo that, in turn, possibly will affect PM tenderness development. It can be hypothesized that increased proteolytic activity pre-slaughter will increase the PM tenderization rate. From postnatal d 28 to d 90 (phase 1) the pigs were divided into two groups, given either ad libitum (A) or restricted (R, 60% of ad libitum) access to feed. The two groups were then divided into two subgroups, given either restricted or ad libitum access to feed from d 91 to slaughter at d 165 (phase 2). Measurements of the activity of mu-calpain, m-calpain, and calpastatin; concentrations of total collagen and the percent of soluble collagen; and RNA, DNA, and elongation factor-2 where made at slaugther. Myofibrillar fragmentation index (MFI) was determined at slaughter and 24 h PM. Warner-Braztler shear force was determined 1 d and 4 d PM. Pigs fed restricted diets in phase 1 and fed ad libitum in phase 2 (RA pigs) had increased growth rates in the last phase compared to pigs fed ad libitum during both phase 1 and phase 2 (AA pigs). The increased growth rate (compensatory growth) was followed by an increased proteolytic potential (mu-calpain:calpastatin ratio), increased MFI values, and higher tenderization rates. There was a positive correlation between the activities of m-calpain and growth rates (r = 0.35, P = 0.03), and between RNA levels and growth rates (r = 0.43, P = 0.006). The proposed hypothesis is largely supported by the results. The activities of both mu- and m-calpain at slaughter were highest in fast-growing pigs. The calpain activity was highest in RA pigs, which in turn also had the fastest growth rates prior tslaughter among the four groups. This implies that the synthesis of these enzymes was up-regulated during the second feeding period to a larger extent in RA pigs. The proteolytic potential and the MFI values indicate that the up-regulated in vivo calpain activity had an effect on PM protein degradation, which also is supported by the higher tenderization rate in RA pigs.

Influence of feeding intensity, grazing and finishing feeding on muscle fibre characteristics and meat colour of semitendinosus, longissimus dorsi and supraspinatus muscles of young bulls.

Forty-one autumn-born Friesian bull calves were allocated to two production systems (Extensive='E' and Intensive='I'). In the E-system, animals were loose-housed and fed a roughage-based diet from October to May, followed by a grazing period from May to October. Ten animals were slaughtered directly from pasture (360 kg BW) and 11 after a 10-week finishing feeding in tie-stalls (460 kg). E-bulls were compared with intensively fed tie-stall housed young bulls (I) slaughtered at comparable weights (360 kg, n=11 and 460 kg, n=9). Semitendinosus (ST), longissimus dorsi (LD), and supraspinatus (SU) muscles were analysed histochemically, and the meat analysed for colour and pigmentation. In LD and SU, Type I % was higher in E- compared with I-bulls (P<0.05-0.006). In ST and LD, Type IIA % was higher in E- compared with I-bulls (P<0.01-0.009). As a result, Type IIB % was lower in all three muscles in E- compared with I-bulls (P<0.05-0.001). In E- compared with I-bulls, Type IIA and IIB fibre areas were larger in ST (P<0.05-0.03) and capillarization was higher in both ST and LD (P<0.001). In all three muscles, the activity of citrate synthase was higher (P<0.07-0.001) and that of lactate dehydrogenase lower (P<0.003-0.001) in E- compared with I-bulls. E-bulls had lower glycogen content than I-bulls in ST and LD at 360 kg, but higher at 460 kg following finishing feeding (P<0.008-0.001). Meat colour (lightness) was darker (P<0.001) and pigmentation was higher (P<0.001) in ST and LD of E- compared with I-bulls, with no effects in SU. In conclusion, histochemically different muscles respond differently to changes in the production system, and differences between the extensive and the intensive production system were narrowed after the finishing feeding.