Effect of residual methane emission on physiological characteristics and carcass performance in Japanese Black cattle.

This study investigated the physiological characteristics and carcass performance associated with residual methane emissions (RME), and the effects of bull differences on CH4-related traits in Japanese Black cattle. Enteric methane (CH4) emissions from 156 Japanese Black cattle (111 heifers and 45 steers) were measured during early fattening using the sniffer method. Various physiological parameters were investigated to clarify the physiological traits between the high, middle, and low RME groups. CH4-related traits were examined to determine whether bull differences affected progeny CH4 emissions. Ruminal butyrate and NH3 concentrations were significantly higher in the high-RME group than in the low-RME group, whereas the propionate content was significantly higher in the low-RME group. Blood urea nitrogen, ß-hydroxybutyric acid, and insulin concentrations were significantly higher, and blood amino acids were lower in the high-RME group than in the other groups. No significant differences were observed in the carcass traits and beef fat composition between RME groups. CH4-related traits were significantly different among bull herds. Our results show that CH4-related traits are heritable, wherein bull differences affect progeny CH4 production capability, and that the above-mentioned rumen fermentations and blood metabolites could be used to evaluate enteric methanogenesis in Japanese Black cattle.

Assessing the impact of three feeding stages on rumen bacterial community and physiological characteristics of Japanese Black cattle.

In Japan, Japanese Black cattle, known for their exceptional meat quality owing to their abundant intramuscular fat, undergo a unique three-stage feeding system with varying concentrate ratios. There is limited research on physiological and rumen microbial changes in Japanese Black cattle during these stages. Therefore, this study aimed to examine Japanese Black steers in these three stages: early (T1, 12-14 months), middle (T2, 15-22 months), and late (T3, 23-30 months). The rumen bacteria of 21 cattle per phase was analyzed using 16S rRNA gene sequencing. Rumen bacterial diversity was significantly higher in T1, with a distinct distribution, than in T2 and T3. Specific phyla and genera were exclusive to each stage, reflecting the shifts in feed composition. Certain genera dominated each stage: T1 had Flexilinea, Streptococcus, Butyrivibrio, Selenomonas, and Kandleria; T2 had Bifidobacterium, Shuttleworthia, and Sharpea; and T3 had Acetitomaculum, Mycoplasma, Atopobium, and Howardella. Correlation analysis revealed significant associations between certain microbial populations and physiological parameters. These findings indicate that changes in energy content and feed composition are associated with physiological and ruminal alterations. This study may guide strategies to improve rumen health and productivity in Japanese Black cattle by modifying diets to specific fattening stages.

Effects of a low-protein diet supplemented with essential amino acids on egg production performance and environmental gas emissions from layer-manure composting in laying hens in the later laying period.

We fed 330-545 day-old laying hens (later laying period) a low-protein diet supplemented with essential amino acids (LPS) and composted their manure. We then investigated the laying performance of the hens, the nitrogen balance and emission of nitrous oxide (N2 O), methane (CH4 ), and ammonia (NH3 ) from the composting, and several characteristics of the finished compost. There were no significant differences in the egg-laying rate, egg mass, egg weight, proximate compositions in egg yolk and egg white, or feed intake between the laying hens fed a Control diet (Cont) and those fed the LPS diet. However, the LPS-fed hens had lower excreta levels and nitrogen excretion. In addition, the environmental gas emissions per layer from composting of the manure from the LPS-fed laying hens were decreased by 9.7% for N2 O, 40.9% for CH4 , and 24.8% for NH3 compared to the Cont-fed laying hens. The concentrations of total nitrogen in the finished compost were similar between the LPS-fed and Cont-fed laying hens. In a vegetable-growth test, the weights of komatsuna plants grown with compost from LPS-fed and Cont-fed hens were also not significantly different. Feeding an LPS diet to 330-545 day-old laying hens was suggested to reduce environmental gas emissions from manure composting without affecting the egg production performance.

Responses in digestion, rumen fermentation and microbial populations to inhibition of methane formation by a halogenated methane analogue.

The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50 % Timothy grass and 50 % concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91 %, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.

Prediction of enteric methane emissions from lactating cows using methane to carbon dioxide ratio in the breath.

The aim of this study was to develop prediction equations for methane (CH4 ) emissions from lactating cows using the CH4 /carbon dioxide (CO2 ) ratio in the breath measured in the automatic milking system (AMS) and to evaluate the predicted values and factors affecting the CH4 /CO2 ratio. The model development was conducted using a dataset determined in respiration chambers or head boxes (n = 121). Then, gas measurements in the AMS as well as in the head box were carried out with six lactating cows fed one of three different levels of neutral detergent fiber (NDF) content, following a 3 × 3 Latin square experimental design. The obtained equation that is suitable for practical use on farms to predict CH4 was CH4 (L/day) = -507 + 0.536 live weight (kg) + 8.76 energy-corrected milk (kg/day) + 5,029 CH4 /CO2 (adjusted R2 = 0.83; root mean square error = 40.8 L/day). Results showed that the predicted values correlated positively with the observed values, the determined CH4 /CO2 ratio increased with increasing dietary NDF content, and the detected eructation rate was in the normal range. On the other hand, the CH4 /CO2 ratio was affected by the time interval between measurement and last eating before the measurement.

Myofibrillar proteolysis in chick myotubes during oxidative stress.

Changes in protein conformation and proteolysis in chick myotubes in response to the induction of oxidative stress by H2O2 treatment were studied. Myotubes were treated for 1 h with H2O2. After this treatment, the H2O2 was removed and the cells were cultured in serum-free medium for 6 and 24 h. Protein carbonyl content, as an index of protein modification, was increased at 6 and 24 h after H2O2 treatment. N(tau)-methylhistidine release, as an index of myofibrillar proteolysis, was also increased at 6 and 24 h after H2O2 treatment. Calpain and cathepsin (B+L and D) activities were increased at 24 but not 6 h after H2O2 treatment. Proteasome activity was increased at 6 and 24 h after H2O2 treatment. These results indicate that oxidative stress increased proteasome activity and caused an increase in myofibrillar proteolysis during short-term incubation, whereas it increased calpain, proteasome and cathepsin activities during long-term incubation, finally resulting in an increase of myofibrillar proteolysis in chick myotubes.

Effects of selenium supplementation on plasma progesterone concentrations in pregnant heifers.

It is known that selenium (Se) has various functions in animals. Many investigations on the biochemical and physiological effects of Se have been previously reported; however, the detailed function of Se in reproduction is not yet clear. We proposed the possibility that Se plays a notable role in progesterone production. The aim of this study was to clarify the effects of Se supplementation on progesterone levels of pregnant Holstein heifers. Eight Holstein heifers (-Se) were fed basal diet (containing 0.022 ppm of Se) throughout the experiment. While a 0.3 ppm diet of Se (sodium selenite) was fed to another seven animals (+Se) with basal diet. Blood sampling was carried out every week. Plasma Se concentrations were higher in Se-supplemented cows compared with controls (-Se) (P < 0.01) throughout the experiment. Se supplementation increased plasma progesterone in the 29-39 weeks of pregnancy from 4.98 ± 0.64 to 6.86 ± 0.49 ng/mL on average (P < 0.05). The present findings suggest that Se contributes to maintaining the function of the corpus luteum and/or placenta in the latter period of pregnancy.

An improved dry ash procedure for the detection of titanium dioxide in cattle feces.

We improved the dry ash procedure for detecting titanium dioxide (TiO2 ) in cattle feces containing chromium oxide [corrected] (Cr(2)O(3) ). First, the effect of amount of sodium sulfate (Na2 SO4 ) on the recovery of TiO2 from cattle feces that contained Cr2 O3 was evaluated. Average recovery of TiO2 at the 2.5 g Na2 SO4 level was significantly higher (P < 0.0001) than that at 0.75 g Na2 SO4 . Second, the effect of Cr2 O3 concentration on the recovery of TiO2 of cattle feces by using two levels of Na2 SO4 addition was examined. The recovery of TiO2 decreased with the increase in the amount of Cr2 O3 at the 0.75 g Na2 SO4 level but was consistently high at 2.5 g Na2 SO4 . Third, the recovery of Cr2 O3 from cattle feces was checked. The recoveries of TiO2 and Cr2 O3 were high enough at the 2.5 g Na2 SO4 level. Fourth, the improved dry ash procedure (5 mL of concentrated H2 SO4 and 2.5 g of Na2 SO4 were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO2 by the improved dry ash procedure was significantly higher (P = 0.0077) than that by the wet ash procedure. Thus, the improved dry ash procedure can be used for TiO2 analysis in cattle feces containing Cr2 O3 .

Influence of high temperature and humidity on rumen bacterial diversity in Holstein heifers.

The effect of heat and humidity stresses on the rumen bacterial molecular diversity of heifers was studied. No statistically significant changes in the rumen microbiota composition were found in the first experiment (average body mass 250kg) while in the second and third experiments (additional variables included the relative humidity and body weight), the microbiota composition was significantly different at elevated environmental temperatures and humidity. These shifts were accompanied by the decrease in concentration of short-chain fatty acids in the rumen.

Effects of serum deprivation on myofibrillar proteolysis in chick myotube cultures.

We examined the effects of serum deprivation on myofibrillar proteolysis in chick myotubes. Myotubes were incubated with serum-free medium for 24 hours. N(tau)-methylhistidine release, as an index of myofibrillar proteolysis, as well as protease activities such as calpain, proteasome, and cathepsins (B+L and D) activities were increased by serum deprivation. These results indicate that serum deprivation induces calpain, proteasome, and cathepsins activities, resulting in an increase in myofibrillar proteolysis in chick myotubes.