Fatty acid‐binding protein expression in the gastrointestinal tract of calves and cows

Fatty acid‐binding protein (FABP) has high affinity for long‐chain fatty acids and appears to participate in the metabolism and intracellular transport of lipids. Liver‐ and intestinal‐type FABP (L‐FABP and I‐FABP, respectively) are expressed in the small intestine. However, in the gastrointestinal tract of ruminants, expression and localization of FABPs are unknown. In this study, we investigated the expression of I‐FABP and L‐FABP in the gastrointestinal tract of cattle. I‐ and L‐FABP had higher messenger RNA (mRNA) and protein expression levels in the duodenum and jejunum relatively to other gastrointestinal regions in both calves and cows. Furthermore, L‐FABP mRNA and protein expression were high in the colon. Both these protein types were confirmed to be in the cytosol of jejunal epithelial cells, where they were found in the villi rather than in the crypts. We concluded that duodenal and jejunal FABPs might be involved in the metabolism of fatty acids mainly in epithelial cells in cattle.     

Role of Ca2+ in corticosterone-induced muscle growth retardation

The increased plasma glucocorticoid concentration in stressful conditions stimulates muscle protein degradation, and results in growth retardation in animals. However, the mechanism is still to be clarified. The present study was undertaken to examine the participation of Ca²⁺ in the glucocorticoid action, using nifedipine (NIF), a Ca²⁺ channel antagonist. The effects of NIF on growth, differentiation, and protein degradation were examined in glucocorticoid-treated primary cultured chick muscle cells. Muscle cell growth and cell differentiation were assessed by protein content and creatine kinase (CK) activity, respectively, and the rate of myofiblillar protein degradation was estimated by the release of N ^τ-methylhistidine (MeHis). Creatine kinase activity was increased by corticosterone (CTC) and this effect was minimized by NIF. Protein content was decreased by CTC and normalized by NIF. N ^τ-methylhistidine release was significantly increased by CTC and tended to be minimized by NIF. The present results indicate that CTC increases skeletal muscle proteolysis followed by muscle growth retardation partially because of enhanced Ca²⁺ influx through the NIF-sensitive Ca²⁺ channel. Enhanced muscle differentiation by CTC is mediated also by the NIF-sensitive Ca²⁺ channel.     

Comparison of feeding systems: feed cost,palatability and environmental impact among hay‐fattened beef,consistent grass‐only‐fed beef and conventional marbled beef in Wagyu (Japanese Black cattle)

The objective of this article is to compare feed cost, palatability and environmental impacts among feeding systems of high concentrate (HC), high hay (HH) and grass‐only‐fed (Gof) groups. Feed cost was the sum of costs paid for feed intake times the price of feed per kilogram. Palatability was measured by a panel taste test using HH and Gof beef and analyzed for differences. Environmental impacts were calculated based on 1 kg of Japanese beef yield of CO₂ equivalents (eq) and animal end weights at each feeding stage. Results showed that the HH and Gof feeding systems could significantly reduce feed costs by approximately 60% and 78%, respectively, from the HC. In the panel taste test, 50% and 47.50% of panelists indicated that HH beef was ‘extremely delicious’ and ‘acceptable,’ respectively, while 15% indicated that Gof beef was ‘extremely delicious’; 62.50% indicated that Gof beef was ‘acceptable.’ Environmental impacts of each feeding system in terms of CO₂ equivalents (eq) were 9.32, 6.10 and 2.04 tonnes of eq for the HC, HH and Gof, respectively. The HH was an economical system that produced moderate impacts on the environment and had impressive taste.     

Muscle type‐specific effect of myostatin deficiency on myogenic regulatory factor expression in adult double‐muscled Japanese Shorthorn cattle

To clarify muscle type‐specific effect of myostatin on myogenic regulatory factors (MRFs), we examined mRNA expression of MRFs in five skeletal muscles of normal (NM) and myostatin‐deficient double‐muscled (DM) adult Japanese Shorthorn cattle by quantitative reverse‐transcribed PCR. Among the four MRFs, namely, Myf5, MyoD, myogenin, and MRF4, MyoD expression was different among the muscles of the DM cattle (P < 0.01) but not of the NM cattle. Meanwhile, MyoD expression was significantly elevated only in masseter (MS) muscle in the DM cattle due to the myostatin deficiency (P < 0.05). Myf5 and MRF4 expression in semitendinosus (ST) was higher in the DM than in the NM cattle (P < 0.05). According to analysis of myosin heavy chain (MyHC) isoform expression, more MyHC‐2x and ‐2a and less ‐slow isoforms were expressed in the longissimus and ST muscles compared to the MS muscle in both cattle (P < 0.05), but no significant difference in MyHC expression was observed between the NM and DM cattle. Taken together, myostatin has influences on Myf5 and MRF4 expression in faster‐type muscles and on MyoD expression in slower‐type muscles, suggesting a possible muscle type‐specific effect of myostatin in skeletal muscle growth and maintenance.     

A monoclonal antibody cross-reactive with three salmonid herpesviruses

Abstract. A monoclonal antibody cross-reactive with strain H-83 Oncorhynchus masou virus (OMV) and Herpesvirus salmonis has been prepared. Western blot analysis revealed that the monoclonal antibody, designated clo. 7, recognized the 16 000 (16K)-polypeptide of these herpesviruses but not the polypeptides of infectious pancreatic necrosis virus or infectious haematopoietic necrosis virus. Clo. 7 showed neither neutralizing activity against strain H-83 nor cytotoxicity to strain H-83-infected RTG-2 cells in the presence of complement. The purified antigen, recognized by clo. 7, from strain H-83 was a polypeptide with a molecular weight of 16K, and sensitive to proteolytic enzymes and sodium periodate, but not to neuraminidase and ethylether. The antigen was heat stable and stable at pH 5·0 – 9·0.