Influence of rice whole‐crop silage diet on growth performance, carcass and meat characteristics and muscle‐related gene expression in Japanese Black steers

Abstract

The present study investigated the influence of a diet largely comprising rice whole-crop silage (rWCS) on growth performance, carcass and meat characteristics, and expression of genes involved in muscle growth of Japanese Black steers. Steers were randomly separated into rWCS-fed (rWCS ad libitum and restricted feeding of concentrate) and concentrate-fed groups. Total digestible nutrient intake and daily gain (DG) decreased in rWCS-fed steers in comparison with concentrate-fed steers, whereas dressed carcass weight and final body weight did not significantly differ between the groups. Decreases in drip loss in the muscle of rWCS-fed steers may be caused by α-tocopherol and β-carotene in muscle. Feeding large amounts of rWCS to steers may maintain quantitative productivity of beef steers equally to a concentrate-based diet, and improve the qualitative productivity. Results of gene expression suggest that activation of skeletal muscle growth in rWCS-fed steers may occur at the late fattening period owing to a decrease in myostatin and increase in myosin heavy chain gene expression. Preadipocyte factor-1 and myostatin genes may be strongly involved in the control of lipid accumulation. This rearing system would allow beef production to switch to rWCS-based diets from concentrate-based diets.

Comprehensive evaluation of growth performance and meat characteristics of a fattening system combining grazing with feeding rice whole‐crop silage in Japanese Black steers

“…Therefore, grazing may be less effective than other diets for beef production because of a decrease in the DG and low productivity. However, feeding a rWCS‐based diet to steers maintained the same productivity level of beef as feeding a concentrate‐based diet (Shibata et al., ). Thus, we can suggest that rWCS could be an effective alternative to a concentrate‐based diet.…”

“…An increase in the expression of genes involved in the ubiquitin–proteasome proteolytic pathway is associated with skeletal muscle wasting (Lecker et al., ; Wing, Haas, & Goldberg, ). Skeletal muscle growth in rWCS‐fed steers may be activated in the late fattening period because of the decreased expression of myostatin (Shibata et al., ). The myostatin transcript levels in the GZ group suggest that the skeletal muscle growth of the steers may have been suppressed during the late grazing period.…”

“…In Japan, beef cattle are generally finished indoors on a concentrate‐based diet throughout the fattening period until slaughter. However, several studies on the different methods of fattening beef cattle have investigated the effects of supplying roughage, such as rice whole‐crop silage (rWCS) (Shibata, Hikino, Imanari, Matsumoto, & Yamamoto, ; Takahira et al., ), grass hay (Muramoto, Aikawa, Shibata, & Nakanishi, ; Shibata, Hikino, & Matsumoto, ), and grazing (Descalzo et al., ; Muramoto, Higashiyama, & Kondo, ; Pavan & Duckett, ), instead of concentrate diets. These previous reports showed that beef cattle can be fattened by feeding roughage or by grazing without necessarily depending on concentrate‐based diet, thereby affecting the growth performance, carcass characteristics, and meat characteristics of the steers.…”

Differences in Circulating microRNAs between Grazing and Grain-Fed Wagyu Cattle Are Associated with Altered Expression of Intramuscular microRNA, the Potential Target PTEN, and Lipogenic Genes

“…The biopsy procedure was as follows: the animal was locally anesthetized by an intramuscular injection of xylazine (Bayer, Tokyo, Japan) and a subcutaneous injection of lidocaine (AstraZeneca, Osaka, Japan). An incision was subsequently made in the skin overlying the LL muscle [25]. All samples were rapidly frozen in liquid nitrogen and stored at -80°C until RNA extraction.…”

“…It was expected that grazing would shift the muscle properties toward slow-oxidative type and decreased adipogenicity, which is associated with expression of miR-206 [29,30], miR-208b [31], and adipogenic genes such as PPARG2 [20,21,25]. Based on this hypothesis, including presumptive declines in the expression of miR-196a, miR-885, PPARG2 , SCD1 , and ELOVL6 by grazing, the significance of the differences in the t -test results for those targets was analyzed at one side.…”