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61.
It is well established in the literature that feeding free vegetable oils rich in oleic acid results in greater milk fat secretion than does feeding linoleic-rich oils. The objectives of these experiments were to analyze the effects of oleic and linoleic acid when fed in the form of full-fat soybeans and the interaction between soybean particle size and fatty acid (FA) profile. Soybeans were included in diets on an iso-ether extract basis and diets were balanced for crude protein using soybean meal. Experiment 1 used 63 cows (28 primiparous, PP; 35 multiparous, MP) housed in a freestall barn with Insentec roughage intake control gates (Marknesse, the Netherlands). Cows were divided into 4 mixed parity groups within the same pen. Two groups were assigned to each of the 2 diets: whole raw Plenish (WP, high oleic; Dupont-Pioneer, Johnston, IA) soybeans or whole raw conventional (WC, high linoleic) soybeans. The MP cows exhibited significantly increased milk fat yield on the WP diet compared with the WC diet. A significantly greater C18 milk FA yield by the MP cows fed WP was observed compared with those fed WC, but no difference was present in the C16 or short-chain FA yield. No effects were seen in the PP cows. Experiment 2 used 20 cows (10 PP, 10 MP) in 2 balanced 5 × 5 Latin squares within parity. Cows received 5 diets: raw WP and WC diets, raw ground Plenish and conventional soybean diets (GP and GC, respectively), and a low fat control. A significant benefit was found for the GP diet compared with the GC diet for milk fat concentration and yield. In experiment 2, no difference was observed between cows fed the WP compared with the WC diet. In experiment 2, cows consuming the Plenish diets produced less milk than when consuming the conventional soybean diets. The soybean diets resulted in significantly more C18 and less <C18 FA compared with the low fat diet. The GP diet resulted in significantly more C18 FA than the GC diet and the ground soybeans resulted in less C16 FA compared with whole soybeans. In both experiments, cows fed the Plenish diets exhibited decreased trans-10 18:1, a FA often increased during milk fat depression, compared with those fed the conventional soybean diets, though differences were not observed in trans-10,cis-12 conjugated linoleic acid. These results indicate that feeding whole soybeans rich in oleic acid may result in some increased milk fat secretion compared with conventional whole soybeans containing high levels of linoleic acid. This advantage is clear for ground high-oleic soybeans compared with ground conventional soybeans. 相似文献
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64.
Population structure and effects of inbreeding on milk yield and quality of Murrah buffaloes 总被引:1,自引:0,他引:1
Santana ML Aspilcueta-Borquis RR Bignardi AB Albuquerque LG Tonhati H 《Journal of dairy science》2011,94(10):5204-5211
To provide data for conservation, selection, and expansion programs of buffalo herds, this study evaluated the history of a population of Murrah buffaloes based on population structure and the effect of inbreeding on accumulated 305-d milk yield (MY), fat yield (FY), protein yield (PY), mozzarella production (MProd), and somatic cell score (SCS). The usefulness of including the individual inbreeding coefficient (F) or individual increase in inbreeding coefficient (ΔF) in the model to describe inbreeding depression was evaluated. Pedigree information from 8,054 animals born between 1976 and 2008 and 4,497 lactation records obtained from 12 herds were used. The realized effective population size was 40.10 ± 1.27, and the mean F of the entire population was 2.14%. The ratio between the number of founders and ancestors demonstrated the existence of a bottleneck in the pedigree of this population, which may contribute to a reduction of genetic diversity. The effect of F on MY, FY, PY, MProd, and SCS was −1.005 kg, −0.299 kg, −0.246 kg, −1.201 kg, and −0.002 units, and the effect of ΔF transformed to equivalent F (%) for a mean of 2.57 equivalent generations was −4.287 kg, −0.581 kg, −0.383 kg, −2.001 kg, and −0.007 units, respectively. The inbreeding depression observed may have important economic repercussions for production systems. The ΔF can be considered the better of the two indicators of inbreeding depression due to its properties that prevent underestimation of this effect. A designed mating system to avoid inbreeding may be applied to this population to maintain genetic diversity. 相似文献
65.
Dietary molasses increases ruminal pH and enhances ruminal biohydrogenation during milk fat depression 总被引:1,自引:0,他引:1
Feeding high-concentrate diets has the potential to cause milk fat depression, but several studies have suggested that dietary sugar can increase milk fat yield. Two experiments were conducted to evaluate the ability of dietary molasses to prevent milk fat depression in the presence of a 65% concentrate diet. In trial 1, molasses replaced corn grain at 0, 2.5, or 5% of diet dry matter in diets fed to 12 second-lactation Holstein cows (134 ± 37 d in milk) in a 3 × 3 Latin square design. Trial 1 demonstrated that replacing up to 5% of dietary dry matter from corn with molasses had positive effects on de novo fatty acid synthesis, increasing the yield of short- and medium-chain fatty acids during diet-induced milk fat depression. Increasing inclusion rate of molasses increased milk fat concentration, but decreased milk yield and milk protein yield. Trial 2 used 7 ruminally cannulated, multiparous, late-lactation Holstein cows (220 ± 18 d in milk) to evaluate effects of dietary molasses on ruminal parameters and milk composition, and also to assess whether increased metabolizable protein supply would alter these responses. Cows were randomly assigned to a dietary treatment sequence in a crossover split plot design with 0 and 5% molasses diets. Dietary treatments were fed for 28 d, with 16 d for diet adaptation, and the final 12 d for 2 abomasal infusion periods in a crossover arrangement. Abomasal infusions of water or AA (5 g of l-Met/d + 15 g of l-Lys-HCl/d + 5 g of l-His-HCl-H2O/d) were administered 3 times daily for 5 d, with 2 d between infusion periods. Administration of AA had no effect on concentration or yield of any milk components. Addition of molasses increased milk fat concentration (2.71 vs. 2.94 ± 0.21%), but had no effect on yields of milk fat or protein. Dietary molasses decreased total volatile fatty acid concentration (141 vs. 133 ± 4.6 mM), decreased the molar proportion of propionate, and increased the molar proportion of butyrate in ruminal fluid. Molasses also increased ruminal pH (5.73 vs. 5.87 ± 0.06), decreased the yield of trans-10 C18:1, and increased the yield of trans-11 C18:1 in milk fat. These data provide evidence that molasses may promote mammary de novo fatty acid synthesis in cows fed high-energy rations by moderating ruminal pH and altering ruminal fatty acid biohydrogenation pathways. 相似文献
66.
北部湾盆地福山凹陷CO2气成因探讨 总被引:1,自引:1,他引:1
北部湾盆地福山凹陷油气钻探中发现了高含CO2气的天然气气藏。对CO2气稳定碳同位素、伴生稀有气体氦和氩同位素进行了分析研究,结果显示,福山凹陷CO2气稳定碳同位素偏重,(13CCO2为-5.01~-10.08‰,绝大多数样品大于-7.0‰,为无机成因CO2气特征;伴生稀有气体氦同位素3He/4He值为(4.74~5.03)×10-6,R/Ra值为3.38~3.59;伴生稀有气体氩同位素40Ar/36Ar值为1881~2190,也显示出幔源或壳幔混合CO2气的特征。综合判定认为,福山凹陷CO2为壳幔混合成因。始新统流沙港组岩浆岩体分布特征与CO2气藏分布范围基本一致,也表明幔源-岩浆可能是福山凹陷CO2气的主要来源。与南海北部边缘盆地其它地区如珠江口盆地西部、琼东南盆地东部CO2气成因一致,都为幔源-岩浆来源,或壳幔混合来源。 相似文献
67.
松辽盆地北部深层断陷构造复杂,制约了断陷优选评价工作.依据沙河子组残留特征与演化规律,将深层断陷划分为“持续沉降型、改造叠合型、继承反转型、改造叠合反转型”4种类型.研究表明:复杂改造叠合型盆地经早期改造并残留下来,往往成为断陷主体或沉积中心,其烃源岩条件较好,同时早期构造活动产生了大量气源断裂,并使地层上倾或者削截方向直接与储集体接触,有利于天然气聚集;持续沉降型断陷盆地沉积环境稳定,有利于暗色泥岩发育,具有较好的源岩条件,后期改造作用弱,有利于天然气保存;将深层断陷划分为Ⅰ,Ⅱ,Ⅲ类勘探区,明确了近期风险勘探的有利区带. 相似文献
68.
本文研究了三七叶总皂苷的抗抑郁作用及其作用机制。40只大鼠随机分成空白组、模型组、氟西汀组和三七叶总皂苷中高剂量组,建立慢性应激抑郁大鼠模型评价三七叶总皂苷的抗抑郁活性以及对海马体cAMP、PKA、BDNF的影响。建模四周后,模型组大鼠与空白组比较,体重、糖水偏好率及自主活动水平等行为学指标分别降低了8.56%、22.48%、26.17%,表现出人类抑郁症中体重下降、快感缺失、自主活动下降等核心症状,而大鼠海马体cAMP、PKA、BDNF的水平分别降低了53.60%、53.60%、39.20%。给予三七叶总皂苷治疗后,与模型组相比,三七叶总皂苷高剂量组大鼠上述三个行为学指标分别增加了7.03%、26.21%、26.21%,上述三个生化指标也分别升高了41.29%、62.79%、49.05%。表明三七叶总皂苷能逆转抑郁大鼠行为学症状以及调节海马体cAMP、PKA、BDNF的水平。三七叶总皂苷具有良好的抗抑郁作用,其作用机制与调控海马体cAMP、PKA、BDNF水平有关。 相似文献
69.
Raghavendra Bhatta Mani Saravanan Luna Baruah Koratekere T Sampath 《Journal of the science of food and agriculture》2012,92(15):2929-2935
BACKGROUND: Plant tannins as rumen modifiers are better than chemicals or antibiotic‐based modifiers since these compounds are natural products which are environmentally friendly and therefore have a better acceptance with regard to feed safety issues. Tropical plants containing phenols such as tannins were found to suppress or eliminate protozoa from the rumen and reduce methane and ammonia production. The screening of these plants is an important step in the identification of new compounds and feed additives which might contribute to mitigate rumen methanogenesis. The present study was carried out to determine the efficacy of tannins from tropical tree leaves for their methane reduction properties. RESULTS: Activity of tannins, as represented by the increase in gas volume with the addition of polyethylene glycol (PEG)‐6000 as a tannin binder (tannin bioassay) was highest in Ficus bengalensis (555%), followed by Azardirachta indica (78.5%). PEG addition did not alter (P > 0.05) methane percentage in Ficus racemosa, Glyricidia maculata, Leucena leucocephala, Morus alba and Semaroba glauca, confirming that tannins in these samples did not affect methanogenesis. The increase (P < 0.05) in protozoa population with PEG was maximal in Ficus religiosa (50), followed by Moringa oleifera (31.2), Azardirachta indica (29.9) and Semaroba glauca (27.5). There was no change (P > 0.05) in the protozoa population in Autocarpus integrifolia, Ficus bengalensis, Jatropha curcus, Morus alba and Sesbania grandiflora, demonstrating that methane reduction observed in these samples per se was not due to defaunation effect of the tannin. The increase in total volatile fatty acid concentration in samples with PEG ranged from 0.6% to > 70%. The highest increase (%) in NH3‐N was recorded in Azardirachta indica (67.4), followed by Ficus mysoriensis (35.7) and Semaroba glauca (32.6) leaves, reflecting strong protein binding properties of tannin. CONCLUSION: The results of our study established that in vitro methanogenesis was not essentially related to the density of protozoa population. Tropical tree leaves containing tannins such as Autocarpus integrifolia, Jatropha curcus and Sesbania grandiflora have the potential to suppress methanogenesis. Therefore tannins contained in these plants could be of interest in the development of new additives in ruminant nutrition. Copyright © 2012 Society of Chemical Industry 相似文献
70.
Qiusheng Li Yuncheng He Yinghou He Kang Zhou Xuliang Han 《Structure and Infrastructure Engineering》2019,15(1):54-71
This article presents the observations of the atmospheric boundary layer (ABL) and wind effects on a 600 m high skyscraper during a landfall typhoon. Wind structure and characteristics throughout the entire ABL are presented and discussed based on records from a Doppler radar wind profiler and near-ground measurements at several meteorological stations. Wind speed profiles with the feature of low-level jets and radial-distance and exposure dependences of gradient height are stressed. Afterwards, wind-induced pressures on building surfaces of the skyscraper are investigated with highlights on non-Gaussian probability distributions of negative pressures and vortex shedding occurred alternately at two sides of the building. The structural responses measured by both accelerometers and strain gauges are analyzed subsequently. Modal parameters of the skyscraper and their dependence on response amplitude are presented and discussed. This study aims to provide useful information for the wind-resistant design of skyscrapers in tropic cyclone-prone regions. 相似文献