Animal Science Journal最新文献

Cryopreservation of oocytes is an important technology for the in vitro gene banking of female germplasm. Although slow freezing is not feasible, porcine oocytes survive vitrification at high rates. Cryopreservation at the germinal vesicle stage appears to be more advantageous than that at the metaphase-II stage. Several factors are considered to affect the success of vitrification and subsequent utilization of immature porcine oocytes such as the device, the protocols for cryoprotectant application, warming, and the post-warming culture. Although live piglets could be obtained from vitrified immature oocytes, their competence to develop to the blastocyst stage is still reduced compared to their non-vitrified counterparts, indicating that there is room for further improvement. Vitrified oocytes suffer various types of damage and alteration which may reduce their developmental ability. Some of these can recover to some extent during subsequent culture, such as the damage of the cytoskeleton and mitochondria. Others such as premature nuclear progression, DNA damage and epigenetic alterations will require further research to be clarified and addressed. To date, the practical application of oocyte vitrification in pigs has been confined to the gene banking of a few native breeds.

The composition of milk fatty acid (FA) was determined using Fourier-transform mid-infrared spectroscopy, which enables the rapid measurement of many samples. Milk FA is one indicator supporting the management of dairy cows and herds. This study aimed to determine an appropriate sampling method for milk FA in a practical farm condition based on intraday and interday variations in milk FA composition during early and late lactation stages. Milk samples were collected in the morning (07:00–08:00 h) and afternoon (16:30–17:30 h) for five consecutive days during early and late lactation. Within the day, de novo FA as the total FA basis was higher in the morning than in the afternoon, whereas preformed FA as the total FA basis was lower in the morning than in the afternoon. The weighted averages of milk FA composition according to milk yield collected in the morning and afternoon were significantly different between cows in early and late lactation; however, these were not significantly different among the consecutive five sampling days in each period. It was concluded that milk samples collected in the morning and afternoon for 1 day are suitable for milk FA determination. These results provide basic data for determining precise sampling methods for practical farms.

We compared the in situ dry matter degradability (ISDMD) and crude protein degradability (ISCPD) of high-moisture corn grain silage and dried corn grains produced in Japan (JHC and JDC, respectively) with corn grains imported from the United States (USC), Brazil (BRC), and South Africa (SAC). The ISDMD values of USC, BAC, and SAC were between those of JHC and JDC, but ISDMD did not differ significantly between USC and SAC. In contrast, ISDMD was lower for BAC than USC and SAC. Overall, our results indicate that ISDMD and ISCPD in the rumen differ between corn grains sources (domestic compared with imported and between production locations), primarily due to differences between the corn varieties represented. In particular, the ISDMD and ISCPD of JHC were greater than those of JDC, and this difference in degradability needs to be considered when using high-moisture corn grain silage as a substitute for dried corn grain as a feed for dairy cattle.

The present study aimed to determine carcass characteristics, meat quality, nutrient profiles, and sensory characteristics of Mithun meat. Sixteen Mithun were selected and divided into four groups, MM-4 (male; n = 4; <4 years of age), MM-47 (male; n = 4; 4–7 years of age), MF-4 (female; n = 4; <4 years of age), MF-47 (female; n = 4; 4–7 years of age). Carcass characteristics showed that adult males (MM-47) have significantly higher (P < 0.05) live weight, carcass weight, and meat-to-bone ratio. Fat (%) was significantly higher (P < 0.05), and deboned meat (%) was lower in MF-4 and MF-47, while marginal differences were observed in bone (%), dressing percentage, and offal yield between groups. Visible marbling increased with age and varied from “slight” to “small” in all groups. Nutrient profiling revealed a significantly higher (P < 0.05) fat percentage and cholesterol in MF-4 and MF-47. Fatty acid profile, amino acid profile, water-soluble vitamins, and minerals content did not differ between groups. However, lysine and leucine (essential amino acids) and glutamic acid and aspartic acid (nonessential amino acids) were most abundant. Effect of age was significant (P < 0.05) on juiciness, tenderness, and connective tissue residue scores. In conclusion, results indicate mithun meat is nutrient-rich regardless of the animal's age or sex.

The objective of this study was to investigate the effects of two different organic selenium (Se) supplements, selenomethionine (Se-Met) and selenohomolanthionine (Se-Hlan), on the serum biochemical parameters and Se status of dairy cows. Different dietary Se supplementation treatments were set as follows: a control group (CON, adding sodium selenite at 0.3 mg Se/kg dry matter [DM]), 0.3 and 0.5 Se-Met (adding Se-Met at 0.3 and 0.5 mg Se/kg DM, respectively), as well as 0.3 and 0.5 Se-Hlan (adding Se-Hlan at 0.3 and 0.5 mg Se/kg DM, respectively). The experiment lasted 8 weeks. The serum measurements showed that both organic Se treatments resulted in higher uric acid than CON. Se-Met produced higher aspartate aminotransferase, glucose, urea, low-density lipoprotein cholesterol, and lactate dehydrogenase than Se-Hlan. Regarding the Se status, the highest milk Se values appeared in 0.5 Se-Met, with intermediate values in 0.3 Se-Met and 0.5 Se-Hlan, whereas the highest and lowest serum Se levels were presented in 0.5 Se-Met and 0.3 Se-Hlan, respectively. Our results suggest that Se-Hlan was not as efficient in boosting serum or milk Se as Se-Met and differences in serum biomarkers between Se-Met and Se-Hlan may be associated with distinct metabolic pathways for different forms of organic Se.

Mammalian oocytes undergo maturation and fertilization in the low-oxygen (O₂) environment of the oviduct. To evaluate the effect of O₂ tension during in vitro maturation and fertilization on embryo yield, quality, cryotolerance, and gene expression, we matured and fertilized bovine cumulus-oocyte complexes under low (5%) or high (20%) O₂ tension. Presumptive zygotes from both groups were cultured at 5% O₂ for 8 days. Blastocysts were vitrified, and then warmed, and cultured for further 24 h to assess their cryotolerance. Our findings indicate that low O₂ during maturation and fertilization enhances embryo development and cell count in both fresh and vitrified/warmed blastocysts. In this study, the interaction of O₂ tension and status (fresh or vitrified/warmed) affected the transcript abundance of SOD2, AQP3, and BAX in blastocysts. These results highlight the role of low O₂ tension during bovine maturation and fertilization and provide support to using 5% O₂ throughout all stages of bovine in vitro embryo production.

Lactation is a characteristic physiological function of mammals and is important for nourishing infants and the dairy industry; however, the molecular mechanisms underlying the function remain to be elucidated. A technique to directly evaluate the quantity and quality of milk in mice is necessary for the study of the lactation mechanism in vivo. By measuring the changes in milk amount after different durations of milk accumulation (0–24 h) using a ductal cannulation technique and oxytocin supplementation, we estimated the milk production rate at a single mammary gland level. In addition, collected milk was available to assess milk quality, including creamatocrit, osmolarity, and concentrations of ions, lactose, and total protein. Moreover, as a proof of principle, the effects of intraductal administration of a hypertonic solution to the abdominal mammary gland were examined. This stimulation increased milk amount, possibly by osmosis, compared with the contralateral control gland. These results demonstrated that this method is useful for examining the lactation ability and mechanisms in vivo. Studies using this method will contribute to the further understanding of lactation mechanisms in mammals.

This experiment aimed to study the degradation characteristics of bagasse after three fermentation treatments in beef cattle. Bagasse 1 was treated with 0.3% lactic acid bacteria (w/w). Bagasse 2 was treated with 0.3% mixed strains (Saccharomyces cerevisiae, Aspergillus niger, Aspergillus oryzae, and lactic acid bacteria at 2:1:1:1). Bagasse 3 was treated with 0.1% cellulase and 0.1% xylanase in addition to 0.3% mixed strains of bagasse 2. The dry matter (DM), crude ash (ASH), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the bagasses were determined. Compared to the control bagasse (without the strain and enzyme treatments), three fermented bagasses showed higher DM after 4 h fermentation. The CP and ASH contents in fermented bagasse 3 were the highest, while the contents of NDF and ADF in fermented bagasse 3 were the lowest among all the groups. The effective degradability of DM, CP, NDF, and ADF was highest in fermented bagasse 3 among the evaluated bagasse feed, followed by fermented bagasse 2 > fermented bagasse 1 > bagasse. Overall, fermented bagasse 3 was better than the control and other treated bagasses, thus fermented bagasse 3 is a hopeful source for ruminant diet of beef cattle.

This study investigated the nausea-like behavior induced by road transportation in goats, and the effects of an anti-motion sickness (MS) medication on this behavior. In the first experiment, 11 adult Shiba goats were road transported twice with either a saline (control) or a commercial anti-MS medication (Travelmin) injection at the first or second transportation. Almost all goats showed nausea-like behavior, which was defined as pointing their heads downward, closing their eyes, and staying relatively still. These goats did not respond when they were touched during blood collection. The anti-MS medication significantly reduced the total time spent in nausea-like behavior (P < 0.05) and tended to increase the frequency of escape attempts during blood collection (P < 0.1). In a second experiment, the effects of the anti-MS medication were examined in goats held under normal housing. The anti-MS medication increased the time spent feeding (P < 0.01) and reduced the time spent in rumination (P < 0.05) but did not change the frequency of lying down nor plasma cortisol concentrations. Our results indicate that the nausea-like behavior in transported goats might be induced, at least in part, by regulatory mechanisms similar to the MS.

High-yielding dairy cows undergo various physiological stresses during the transitional phase of the calving cycle. In this period, they experience negative energy balance, subjecting the liver to significant metabolic stress from an influx of nonesterified fatty acids. This metabolic stress not only impairs liver function but also diminishes milk production. Early lactation dairy cows may develop endoplasmic reticulum (ER) stress in the liver, potentially leading to liver-related diseases and contributing to ER stress in mammary epithelial cells, resulting in decreased milk production. Natural products that alleviate ER stress have been identified, and if further in vivo studies confirm their efficacy, they have potential as feed additives to prevent disease and reduce milk yield. Conversely, physiological levels of ER stress play a role in mammary gland development and positively influence protein synthesis in milk. Understanding the threshold level of ER stress in mammary tissue and its detailed mechanisms will be crucial in dairy farming.