Effect of Indoor Concentrate Feeding vs. Outdoor Grazing on the Expression of Genes Involved in Muscle Growth and Nutrient Content in Japanese Black Steer Muscle

The objective of the present study was to investigate the effect of outdoor grazing on the expression of genes involved in muscle growth and the nutrient contents of skeletal muscle in steers. Ten Japanese Black steers were divided into two groups: grazing (GR) and concentrate (CT) groups. Crude protein, extractable lipid, moisture, fatty acid, cooking loss and Warner Bratzler shear force in muscle tissue were analyzed. The gene expression of myosin heavy chain (MyHC) isoform (2a, 2x and slow), myostatin, follistatin, peroxisome proliferator-activated receptor γ2 (PPARγ2), CCAAT/enhancer binding protein α (C/EBPα), heat shock protein (HSP) 27 and HSP40 in skeletal muscles was evaluated at the end of fattening. Decreases in MyHC-2a and MyHC-2x (fast-twitch fiber type) expression in the longissimus lumborum (LL) muscle were detected in the GR group compared with the CT group;in contrast, an increase in MyHC-slow (slow-twitch fiber type) expression was shown in the GR group. These results suggest that grazing initiated muscle fiber type conversion to slow-twitch from fast-twitch. A decrease in extractable lipid content was observed in the GR group in the LL and semitendinosus (ST) muscles. Crude protein content in the LL muscle in the GR group was higher than in the CT group. MyHC expression in LL muscle in the GR group was greater than in the CT group. A decrease in myostatin and PPARγ2 gene expression was detected in the GR group compared with the CT group in both muscles. Expression of C/EBPα in LL muscle in the GR group was lower than in the CT group. These results suggest that grazing steers at the end of fattening may lead to an increase in protein content and a decrease in fat accumulation in LL and/or ST muscles by regulation of myostatin, MyHC, PPARγ2 and C/EBPα gene expression.

Comparative sensitivity to environmental variation and human disturbance of Asian tapirs (Tapirus indicus) and other wild ungulates in Thailand

Southeast Asia’s tropical forests suffer the highest rates of deforestation and disturbance of any on Earth,with poorly understood impacts on native fauna.Asian tapirs(Tapirus indicus)are among the least studied of the large mammals in these forests.Using records from 9 camera trap surveys in 7 of the largest(>1000 km2)pro-tected area complexes,we assessed the influence of environmental variation and human-induced disturbance on tapir occurrence.Tapirs were detected at 13%of locations sampled,significantly associated with evergreen for-est(P<0.001).A multiple logistic regression model predicted tapir presence 87%of the time.According to this model,tapir occurrence was positively influenced by annual rainfall and proximity to the forest edge.Howev-er,tapirs may not avoid edges but instead prefer wetter evergreen forest,a habitat type that tended to occur fur-ther from the forest edge at higher elevations in our particular study sites(P<0.001).By comparison,4 other wild ungulate species that share habitats with tapirs showed a range of differing responses.Tapirs are expect-ed to be less sensitive to disturbance because they are not targets for hunting and trade,and are almost entire-ly active at night,so avoid peak traffic periods in parks.Tapir populations in Thailand may be more stable than in other parts of their global range because rates of forest loss have decreased>40%over the past 20 years.We recommend surveys to fill gaps in the understanding of the status in lesser-known protected areas,research to better understand the fine-scale environmental influences on behavior and habitats of tapirs,and other forest un-gulates,and continued legal status for tapirs in the highest category of protection.