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Objective: To examine whether beta2-adrenergic agonist-induced hypertrophy of the quadriceps skeletal muscle can modulate the severity of osteoarthritis (OA) in the rodent meniscectomy (MNX) model.Methods: Male Lewis rats were subcutaneously administered with 1.5 mg/kg/day clenbuterol hydrochloride (n=15) or saline vehicle (n=20) for 14 days. Following pre-treatment, five animals from each group were sacrificed to assess the immediate effects of clenbuterol. The remaining animals underwent either invasive knee surgery (clenbuterol pre-treated n=10; saline pre-treated n=10) or a sham control surgical procedure (saline pre-treated n=5). During disease initiation and progression, weight bearing was assessed by hindlimb loading. Myosin heavy chain (MHC) protein isoforms were quantified by silver stained SDS PAGE. OA severity was graded by assessment of toluidine blue stained step coronal sections of the total knee joint.Results: Clenbuterol treatment resulted in an increase in total bodyweight, growth rate and in quadriceps skeletal muscle mass. Meniscal surgery resulted in the development of OA-like lesions, changes to weight bearing, and changes in MHC protein expression in the quadriceps. Clenbuterol-induced skeletal muscle hypertrophy had no effect on either weight bearing or articular pathology following MNX surgery.Conclusions: Our data reveal that clenbuterol-induced skeletal muscle hypertrophy is unable to mimic the beneficial clinical effects of increased musculature derived through targeted strength training in humans, in a rodent model of MNX-induced OA. In addition we observed fibre-type switching to "slow twitch" in the quadriceps muscle during the induction of OA that warrants further investigation as to its relationship to joint stability. [ABSTRACT FROM AUTHOR]

Summary: Objective: To examine whether β2-adrenergic agonist-induced hypertrophy of the quadriceps skeletal muscle can modulate the severity of osteoarthritis (OA) in the rodent meniscectomy (MNX) model. Methods: Male Lewis rats were subcutaneously administered with 1.5mg/kg/day clenbuterol hydrochloride (n =15) or saline vehicle (n =20) for 14 days. Following pre-treatment, five animals from each group were sacrificed to assess the immediate effects of clenbuterol. The remaining animals underwent either invasive knee surgery (clenbuterol pre-treated n =10; saline pre-treated n =10) or a sham control surgical procedure (saline pre-treated n =5). During disease initiation and progression, weight bearing was assessed by hindlimb loading. Myosin heavy chain (MHC) protein isoforms were quantified by silver stained SDS PAGE. OA severity was graded by assessment of toluidine blue stained step coronal sections of the total knee joint. Results: Clenbuterol treatment resulted in an increase in total bodyweight, growth rate and in quadriceps skeletal muscle mass. Meniscal surgery resulted in the development of OA-like lesions, changes to weight bearing, and changes in MHC protein expression in the quadriceps. Clenbuterol-induced skeletal muscle hypertrophy had no effect on either weight bearing or articular pathology following MNX surgery. Conclusions: Our data reveal that clenbuterol-induced skeletal muscle hypertrophy is unable to mimic the beneficial clinical effects of increased musculature derived through targeted strength training in humans, in a rodent model of MNX-induced OA. In addition we observed fibre-type switching to “slow twitch” in the quadriceps muscle during the induction of OA that warrants further investigation as to its relationship to joint stability. [Copyright &y& Elsevier]

Abstract: The present study investigated the relationship between muscle type and components of the caspase protease system in porcine trapezius (TZ), psoas (PS), longissimus dorsi (LD) and semitendinosus (ST) muscles. Muscles were classified according to slow and fast myosin heavy chain (MHC) content determined by western blotting. MHC slow, but not MHC fast protein expression was significantly different between muscles (p <0.001). Protein levels of caspases 3, 8 and 12 and the caspase inhibitor apoptosis repressor with caspase recruitment domain (ARC) were determined. In addition the level of caspase 3 mRNA and activity levels of caspase 3/7 were determined. There was a significant difference in protein levels and activity between muscles (p <0.01), although no difference was observed in mRNA abundance. The data show that multiple components of the caspase system are expressed in porcine skeletal muscle and that their levels are variable, but there is not a distinct association of expression with a particular muscle. [Copyright &y& Elsevier]

The present study investigated the relationship between fibre type distribution and slow (MHC-s) and fast (MHC-f) myosin heavy chain content on calpastatin and meat tenderness in longissimus dorsi (LD), tensor fasciae latae (TFL), semitendinosus (ST), trapezius (TZ) and supraspinatus (SS) muscles from six Mule×Charolais rams. Samples taken at slaughter were frozen either in liquid N2 for analysis of MHC-s and MHC-f by immunoblotting, or in cooled isopentane for histochemical fibre typing. Calpastatin activity and an immunoreactive 135 kDa calpastatin band were analysed in samples taken 24 h postmortem. Shear force was determined on muscle chops taken at 24 h postmortem and conditioned until day 14. The intensity of MHC-s and MHC-f immunopositive bands correlated with %Type I and %Type II fibres identified histochemically (r2=0.612 and 0.366, respectively, p<0.001). Muscle specific differences were observed in MHC-s and MHC-f immunoreactivity, fibre type distribution, calpastatin activity, calpastatin 135 kDa immunoreactivity and shear force. MHC-s correlated positively with calpastatin activity (r2=0.725, p<0.001) and 135 kDa calpastatin (r2=0.228, p<0.01) across all muscle types. The data show that detection of MHC-s can be used to identify fibre type differences between ovine muscles and that this correlates with differences in calpastatin content and inhibitory activity, but not tenderness. [Copyright &y& Elsevier]

A soy-protein isolate diet that was deficient in methionine (Met), zinc (Zn), riboflavin, vitamin B-6 and choline for chick growth (Assay 1) was used to study individual or multiple deficiencies of several of these nutrients. In all cases, adding all three deficient nutrients together resulted in growth responses that were superior to those resulting from supplementation with any pairs of deficient nutrients. In Assay 2, single addition of Zn but not of methionine or riboflavin produced a growth response, but the combination of either Zn and Met or Zn and riboflavin resulted in growth responses that were greater than the response elicited by Zn alone. Assay 3 involved individual or multiple deficiencies of choline, riboflavin and vitamin B-6, and individual additions suggested that choline was first limiting. Choline + riboflavin supplementation, however, produced marked growth and gain:food responses that were far greater than those resulting from supplemental choline or riboflavin alone. Moreover, the growth response to a combination of choline + pyridoxine (PN) was also greater than that obtained from any of the three nutrients fed alone; even PN + riboflavin (in the absence of choline) produced responses greater than those observed with the unsupplemented negative-control diet. In Assay 4, chicks responded to individual additions of riboflavin, PN or Met, and in Assay 5, to either riboflavin or PN; all two-way combinations resulted in growth rates that were far greater than those occurring with any single addition. The data from these experiments show that unlike the situation with three deficient amino acids, the expected responses to first-, second- and third-limiting B-vitamins or deficient vitamins combined with deficient levels of Zn or Met do not follow the expected pattern of response to first-, further response to first- and second- and an even further response to first-, second- and third-limiting nutrients. [ABSTRACT FROM AUTHOR]

The objective of the current study was to evaluate the impact of increasing manganese (Mn) hydroxychloride on growth performance and tibia strength of male broilers fed corn-soy diets. A total of 35 Ross 708 male broilers per pen were assigned to dietary treatments containing Mn hydroxychloride at 0, 40, 80, 120, and 160 ppm, respectively. Broilers were fed for a 55 d period. Performance parameters were evaluated, and on days 42 and 55, 5 right tibias from each pen were excised for determination of mineral characteristics. Manganese had no statistical impact on body weight (BW) throughout the duration of the study. During the later stages of production, broilers fed diets containing elevated levels of Mn at or above 80 ppm had improved (P < 0.05) feed conversion ratio (FCR) compared to the birds fed diets containing 0 ppm. Regression analysis correlated elevated dietary Mn with improved FCR through day 14, 28, 42, 49, and 55 and increased Mn tibia concentration on days 42 and 55. At the termination of the study, broilers fed Mn at 160 ppm exhibited improved (P < 0.05) tibia breaking strength as compared to broilers fed 80 and 120 ppm Mn. These data indicate that the dietary concentration of Mn needed to maximize growth performance is higher than the reported value in the NRC (1994) of 60 ppm. Additionally, the requirement to maximize bone strength in heavier broilers may be elevated as compared to the requirement to maximize BW and feed intake. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to evaluate the influence of copper supplementation in diets varying in amino acid (AA) density on growth performance, apparent metabolizable energy (AMEn), apparent ileal nutrient digestibility (AID), and plasma carotenoids in broilers infected with Eimeria acervulina. Ross 308 male broilers (480 total) were housed in battery cages and allotted to 8 experimental treatments in a factorial arrangement of 2 dietary AA densities [1.00% (LAA) or 1.20% (HAA) digestible Lys], 2 supplemental copper concentrations (zero or 116 mg/kg), and 2 E. acervulina infection states (uninfected or infected). Essential AA ratios relative to digestible Lys were similar in both the LAA and HAA diets, and copper was provided by 200 mg/kg of tribasic copper chloride (58% copper). Chicks received experimental diets from 2 to 21 d post hatch and 6 replicate cages of 10 birds per cage were assigned to each treatment. Broilers were inoculated with zero or 6.3 x 105 sporulated E. acervulina oocysts at 15 d and blood and ileal digesta were collected at 21 days. From 2 to 15 d, body weight gain and G:F of broilers were improved (P < 0.05) with increasing AA density, and an AA density x copper interaction was observed (P < 0.05) for feed intake. Eimeria infection reduced (P < 0.05) plasma carotenoids, growth performance, dietary AMEn, and AID of organic matter, nitrogen, and total AA. There were no interactive effects of dietary treatments with E. acervulina infection on broiler growth performance or dietary AMEn. An AA density x copper supplementation interaction was observed (P < 0.05) for AID of total AA, whereby copper supplementation increased AID of total AA for birds fed the LAA diet and decreased AID of total AA for birds fed the HAA diet. In summary, E. acervulina-induced reductions in nutrient digestibility were dependent on dietary copper and AA status, but changes in digestibility had minimal impact on growth performance of broilers during the E. acervulina infection period. [ABSTRACT FROM AUTHOR]

An abstract of the paper "Impact of a Bacterial Phytase on Broiler Chickens When Fed Simple or Complex Diets," by T. M. Parr and colleagues is presented.

Study of stearoyl-coenzyme A desaturase (SCD) gene expression in the bovine mammary gland is limited by restricted availability of mammary tissue samples from biopsy or postmortem sampling of cows during temporal experiments. A technique was developed to isolate total RNA from somatic cells in bovine milk and to analyze SCD mRNA expression by quantitative reverse-transcription PCR. Total RNA yield was lower than in a previous goat study and was related to numbers of viable somatic cells. To obtain sufficient total RNA, 1-L milk samples were taken and stored for up to 24 h at 4°C. Complementary DNA prepared from somatic cells showed a 99% match with the published sequence for SCD mRNA in bovine adipose tissue. Stearoyl-CoA desaturase mRNA abundance relative to β-actin mRNA for 12 cows sampled across 4 time points varied (mean ± SE) from 0.88 ± 0.17 to 4.40 ± 0.50. Fifty-five percent of variation was due to individual cows and 42% was due to daily variation within cows. Relative abundance of SCD mRNA was not related to the number of viable somatic cells or total RNA extracted from samples, but it was related to mammary desaturase activity, as indicated by changes in milk C14 fatty acid concentrations. We concluded that somatic cells provide a noninvasive and repeatable alternative to mammary tissue samples obtained by biopsy or postmortem. [ABSTRACT FROM AUTHOR]

The present study was conducted to determine the effects of growth pattern on the calpain system and meat tenderization. Twenty-four Friesian calves were randomly allocated to three treatment groups: FAST (fast growth rate), SLOW (severely restricted growth rate) and ALTER (restricted growth for 30 days followed by fast growth rate). Four animals from each group were slaughtered on day 32 or 45 after altering the growth rates. Samples of M. longissimus dorsi were rapidly frozen at slaughter for protein analysis by Western blotting. Restricted growth reduced the immunoreactivity of a calpastatin band (135 kDa) measured at 24 h postmortem. Immunoreactivity associated with the large subunit of μ- or m-calpain appeared to be unaffected by growth patterns. Shear force measurements taken after 14 days of conditioning were positively related to 135 kDa calpastatin at 24 h postmortem. In this study there was no clear relationship between shear force and growth pattern. [Copyright &y& Elsevier]

Effects of hydroxychloride (OHCl) and sulfate form of zinc and manganese supplementation on immune responses of birds fed marginally lower levels of zinc and manganese during an experimental lipopolysaccharide (LPS) injection were studied. In experiment I, 30-week-old layer birds were fed 50 mg/kg Zn+45 mg/kg Mn or 100 mg/kg Zn+90 mg/kg Mn in sulfate or OHCl form and injected with 0 or 500 μg/kg LPS in a 2 (50 mg Zn+45 mg Mn and 100 mg Zn+90 mg Mn) X 2 (sulfate and OHCl) X 2 (0 and 500 μg LPS) factorial setup of treatments for 10 weeks. Among LPSinjected birds, those receiving 50 mg ZnOHCl+45 mg MnOHCl had comparable heterophil and monocyte superoxide dismutase (SOD) activity compared to the birds fed 100 mg Zn+90 mg Mn. Compared to the birds injected with PBS, LPS injection upregulated cathelicidin and IL-1 relative mRNA amounts in monocytes from birds fed 100 mg Zn+90 mg Mn, both in sulfate and OHCl form, and in birds fed 50 mg ZnOHCl+45 mg MnOHCl, but not in the birds fed 50 mg ZnSO4+45 mg MnSO4. In experiment II, oneday- old broiler birds were fed 50 mg ZnOHCl+45 mg MnOHCl, 50 mg ZnOHCl+90 mg MnOHCl, 100 mg ZnOHCL+45 mg MnOHCl, 100 mg ZnOHCl+90 mg MnOHCl, 50 mg ZnSO4+45 mg MnSO4, or 100 mg ZnSO4+90 mg MnSO4 for 21 and 42 days. Birds fed 100 mg ZnOHCl+45 mg MnOHCl form had a comparable heterophil and monocyte SOD activity and monocyte cathelicidin mRNA amounts compared to the group fed 100 mg Zn+90 mg Mn. Increasing the ZnOHCl content from 50 mg to 100 mg/kg Zn reversed (P > 0.05) the decrease in SOD activity and monocyte cathelicidin mRNA levels of the 50 mg ZnOHCl+45 mg MnOHCL fed group, and increasing the MnOHCl content from 45 mg to 90 mg/kg in the 100 mg ZnOHCl+45 mg MnOHCl group further increased SOD activity. In conclusion, birds fed diets with lower amounts of zinc and manganese in sulfate form decreased SOD activity and IL-1 and cathelicidin amounts during inflammation, and either increasing the dietary zinc and manganese content or feeding zinc and manganese in OHCl form synergistically increased the SOD activity and IL-1 and cathelicidin mRNA amounts in immune cells. [ABSTRACT FROM AUTHOR]

An abstract of the paper "Evaluation of a bacterial phytase on nutrient metabolism and performance in broiler chickens," by C. Wyatt and colleagues is presented.

Background Basal-like and triple-negative breast tumours encompass an important clinical subgroup and biomarkers that can prognostically stratify these patients are required. Materials and methods We investigated two breast cancer tissue microarrays for the expression of calpain-1, calpain-2 and calpastatin using immunohistochemistry. The first microarray was comprised of invasive tumours from 1371 unselected patients, and the verification microarray was comprised of invasive tumours from 387 oestrogen receptor (ER)-negative patients. Results The calpain system contains a number of proteases and an endogenous inhibitor, calpastatin. Calpain activity is implicated in important cellular processes including cytoskeletal remodelling, apoptosis and survival. Our results show that the expression of calpastatin and calpain-1 are significantly associated with various clinicopathological criteria including tumour grade and ER expression. High expression of calpain-2 in basal-like or triple-negative disease was associated with adverse breast cancer-specific survival (P = 0.003 and <0.001, respectively) and was verified in an independent cohort of patients. Interestingly, those patients with basal-like or triple-negative disease with a low level of calpain-2 expression had similar breast cancer-specific survival to non-basal- or receptor- (oestrogen, progesterone or human epidermal growth factor receptor 2 (HER2)) positive disease. Conclusions Expression of the large catalytic subunit of m-calpain (calpain-2) is significantly associated with clinical outcome of patients with triple-negative and basal-like disease. [ABSTRACT FROM PUBLISHER]

The article presents an abstract of the research paper "Evaluation of an inherent thermo-tolerant bacterial phytase in commercial feed mills and the use of a new assay method for determining phytase activity in animal feeds," by R. Upton and colleagues.