The aim of this study was to investigate the effects of melatonin and follicle-stimulating hormone (FSH) on the in vitro culture of goat preantral follicles. Ovarian fragments were cultured for 7 d in α-minimum essential medium (α-MEM+) containing melatonin (100, 250, 500, or 1,000 pM), FSH (50 ng/mL), or a combination of the 2 hormones and further analyzed by histology and transmission electron and fluorescent microscopy. The results showed that after 7 d of culture, tissues cultured in α-MEM+ alone or supplemented with FSH alone, melatonin (500 and 1,000 pM), or the combination of FSH and melatonin (1,000 pM) maintained percentages of normal preantral follicles similar to the fresh control. In contrast to the noncultured tissues, the percentage of developing follicles was increased under all culture conditions after 7 d (P < 0.05). The addition of 1,000 pM melatonin associated with FSH to the culture medium increased follicular and oocyte diameters compared with α-MEM+ alone after 7 d of culture (P < 0.05). Ultrastructural and fluorescent analyses confirmed the integrity of follicles cultured with 1,000 pM of melatonin plus FSH for 7 d. In conclusion, this study demonstrated that the interaction between melatonin and FSH maintains ultrastructural integrity and stimulates further growth of cultured caprine preantral follicles. 相似文献
Silvopastoral system (SPS) has been suggested to ensure sustainability in animal production systems in tropical ecosystems. The objective of this study was to evaluate the productive and nutritive value traits of Brachiaria decumbens and performance of dairy heifers in SPS and open pasture (OP) during the summer and autumn of two consecutive years in the SPS and OP (17th and 18th years after establishment). Experimental design was a randomized complete block with two treatments (SPS and OP) and three replications in subdivided plots with repeated measures in time. There was reduction in the tiller population density, total and green forage mass, and total and green forage bulk density in the SPS when compared to the OP in the summer. In the autumn, no difference was observed between the systems. Shading in SPS increased crude protein content of the grass pasture by 25% and 33% when compared to the OP during the first and second experimental years, respectively, and reduced neutral detergent fibre content. However, it did not change acid detergent fibre or lignin content. OP provided higher stocking rate and weight gain per area than the SPS. Average daily gain was higher in the OP in the second experimental year. Severe shading conditions should be avoided, because in the long ‐ term they may threaten the persistence and sustainability of pasture in the SPS. It is recommended to plant a low density of trees or implement management strategies of the tree component by either thinning or pruning over the years after planting. 相似文献
Increased atmospheric carbon dioxide (CO2) is a consequence of recent anthropogenic environmental changes, and few studies have evaluated its effects on tropical grasses used in Brazilian pastures, the main feed source for major part of ruminant livestock. This study evaluated forage production, chemical composition, in vitro total gas production and organic matter degradability of Brachiaria brizantha under contrasting CO2 atmospheric conditions in a free air carbon dioxide enrichment (FACE) facility. The forage plants were sown in each of the 12 octagonal rings of the FACE facility: six under ambient atmospheric CO2 concentration of approximately 390 μmol/mol, hereafter referred to as control (CON) plots, and other six rings enriched with pure CO2 flux to achieve a target CO2 concentration of 550 μmol/mol, hereafter called elevated CO2 (eCO2) plots. Soil samples were collected to determine carbon and nitrogen concentrations. After seventy days of sowing, a standardization cutting was performed and then at regular intervals of 21 days the forage was harvested (ten harvest dates) and forwarded to laboratorial analyses. Forage above‐ground biomass production (dry matter (DM): 6,143 vs. 6,554 kg/ha), as well as morphological characteristics (leaves: 71% vs. 68%; stem: 28% vs. 31%), chemical composition (crude protein: 162.9 vs. 161.8; neutral detergent fibre: 663.8 vs. 664.3; acid detergent fibre: 369.5 vs. 381; lignin: 60.1 vs. 64.1 g/kg DM; total C: 45.9 vs. 45.9; total N: 2.8 vs. 2.8; total S: 0.2% vs. 0.2%), organic matter in vitro degradability (573.5 vs. 585.3 g/kg), methane (5.7 vs. 4.3 ml/g DM) and total gas (128.3 vs. 94.5 ml/g DM) production did not differ significantly between CON and eCO2 treatments (p > .05). The results indicated that at least under short‐term enrichment, B. brizantha was not affected by eCO2. 相似文献
This study reports for the first time the presence of diazotrophic bacteria belonging to the genera Achromobacter and Zoogloea associated with wheat plants. These bacterial strains were identified by the analysis of 16S rDNA sequences. The bacterium
IAC-AT-8 was identified as Azospirillum brasiliense, whereas isolates IAC-HT-11 and IAC-HT-12 were identified as Achromobacter insolitus and Zoogloea ramigera, respectively. A greenhouse experiment involving a non-sterilized soil was carried out with the aim to study the endophytic
feature of these strains. After 40 days from inoculation, all the strains were in the inner of roots, but they were not detected
in soil. In order to assess the location inside wheat plants, an experiment was conducted under axenic conditions. Fifteen
days after inoculation, preparations of inoculated plants were observed by the scanning electron microscope, using the cryofracture
technique, and by the transmission electron microscope. It was observed that all isolates were present on the external part
of the roots and in the inner part at the elongation region, in cortex cells, but not in the endodermis or in the vascular
bundle region. No colonizing bacterial cells were observed in wheat leaves. 相似文献
We investigated the effect of vaccination of male beef calves (mean age+/-S.D.: 158+/-31 days) against bovine herpes virus (BHV-1 or IBR virus), bovine respiratory syncitial virus (BRSV), bovine viral diarrhea (BVD) virus and para-influenza (PI(3)) virus on the incidence of respiratory disease during the first forty days after weaning and entering a feed-lot in Portugal. In May 2003, Mertolenga, Preta and mixed-breed calves from 10 different beef herds, were systematically assigned (by order of entrance in a chute) to two treatment groups, before moving to a common feed-lot. One hundred and twenty five male calves were vaccinated with a quadrivalent vaccine (Rispoval 4) and revaccinated after 21-27 days while 148 herdmates were injected with saline (0.9% NaCl) on the same occasions. The incidence and severity of clinical cases of "bovine respiratory disease" (BRD) were evaluated every day during the first 40 days after entering the feed-lot. Morbidity (3% vs. 14%) and mortality (0% vs. 4%) due to BRD were significantly lower in the vaccinated group. Ten days after revaccination, the calves were treated with an antimicrobial - ending the study - after an outbreak of BRD caused a high incidence of disease in the non-vaccinated group. In conclusion, our results showed that Rispoval 4, a quadrivalent vaccine against respiratory viruses, under field conditions, reduces morbidity and mortality due to BRD in beef calves after weaning. 相似文献
The objective of this study was to evaluate the production, consumption, and energy balance parameters of primiparous 3/4 and 7/8 Holstein × Gir (HG) dairy cows fed two diets of differing energy levels during the postpartum period. At the beginning of the study, 28 days prepartum, the average weight of both genetic groups was 498?±?12 kg and body condition score (BCS) was 3.5?±?0.05. At the end of the study, 61 days postpartum, the 3/4 HG cows had higher weight and body condition scores than the 7/8 HG (456?±?8 and 429?±?8 kg and 3.13?±?0.03 and 2.94?±?0.03 BCS for 3/4 HG and 7/8 HG, respectively). Milk from cows fed the high-energy diet had higher percentages of fat, protein, lactose, and total dry extract than cows fed the low-energy diet. Cows fed the high-energy diet had higher net energy intake (95.3?±?1.9 vs. 88.1?±?2.1 MJ/day) and higher energy balance (3.64?±?2.13 vs ??6.02?±?2.30 MJ/day). The 3/4 HG cows displayed higher energy for maintenance (33.1?±?0.4 MJ/day) than the 7/8 HG (31.5?±?0.5 MJ /day). In conclusion, although the primiparous 3/4 HG were heavier than the 7/8 HG and had a higher body condition score, no differences in milk produced up to 60 days postpartum were observed. The higher energy diet during the postpartum period increased energy balance, resulting in higher production of milk fat, protein, and lactose.
Experiment I: T1‐1 = basal diet with 25% crude protein (CP) + limiting amino acids (LA); T1‐2 = 20% CP + LA; T1‐3 = 20% CP + LA + L‐glycine; T1‐4 = 20% CP + LA + L‐glutamate; T1‐5 = 20% CP + LA + L‐glycine + L‐glutamate. Experiment II: T2‐1 = basal diet with 22% CP + LA; T2‐2 = 20% CP + LA; T2‐3 = 17.6% CP + LA + L‐glycine; T2‐4 = 17.6% CP + LA + L‐glutamate; T2‐5 = 17.6% CP + LA + L‐glycine + L‐glutamate. The reduction of dietary protein based on the concept of ideal protein decreases nitrogen excretion in quails when L‐glycine is added to the diets. Quails fed diets supplemented with L‐glutamate as the non‐specific nitrogen source equivalent to the nitrogen level of the control diet had increased nitrogen excretion. However, quails had reduced nitrogen excretion in both experiments when L‐glycine was added to diets with L‐glutamate. Carcass fat was increased by reducing dietary protein, but fat deposition was reduced by adding L‐glutamate and L‐glycine, or both. The dietary addition of L‐glutamate and L‐glycine in quails based on the ideal protein concept is not necessary (Exp. I). Although the total nitrogen, electrolytic balance and glycine level were adjusted in diets, quails had decreased performance. Therefore, other hypotheses besides protein reduction need to be studied (Exp. II). Protein reduction with supplementation of only limiting essential amino acids does not affect quail performance. Dietary addition of L‐glycine reduces nitrogen excretion. 相似文献