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1.
Bryszewska MA Ambroziak W Langford NJ Baxter MJ Colyer A Lewis DJ 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(3):121-126
The potential of selenium-enriched rye/wheat sourdough bread as a route for supplementing dietary selenium intakes is reported.
In addition to their normal diets, 24 female volunteers (24 to 25 years old) were fed either selenium-enriched bread or non-enriched
bread each day (68.02 and 0.84 μg selenium day−1 respectively) for 4 weeks. The chemical form of the selenium in the bread had been characterised using HPLC-ICP-MS, which
showed that 42% of the extractable selenium was present as selenomethionine. Plasma selenium levels and plasma platelet glutathione
peroxidase (GPx1) activity were measured in the volunteers’ blood over a 6-week period. A statistically significant difference
(p = 0.001) was observed in the mean percentage change data, calculated from the plasma selenium level measurements for the
enriched and control group, over the duration of the study. A comparable difference was not observed for the platelet GPx1
activity (p = 0.756), over the same period. Two weeks after cessation of the feeding stage, i.e., at t = 6 weeks, the mean percentage change value for the selenium plasma levels in the enriched group was still significantly
elevated, suggesting that the absorbed selenium had been incorporated into the body’s selenium reserves, and was then being
slowly released back into the volunteers’ blood. 相似文献
2.
Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or 相似文献
3.
Supplementation of dairy cows with a fish oil containing supplement and sunflower oil to increase the CLA content of milk produced at pasture 总被引:1,自引:0,他引:1
It has been shown that the cis 9, trans 11 isomer of conjugated linoleic acid (CLA) can be increased in milk by supplementation with fish oil and vegetable oils. Feeding a high level of oil, however, can impact negatively on gross milk composition. The principal aim of this study was to determine if relatively low levels of fish oil or sunflower oil, either alone or in combination, offered to dairy cows on pasture would increase the C18:2 cis 9, trans 11 CLA concentration in milk. Forty autumn-calved cows on a diet of grazed grass were assigned to 4 supplementation treatments: (i) No supplement (P), (ii) 255 g/day of sunflower oil (SO), (iii) 255 g/day of sunflower oil + 52.5 g/day of fish oil (SOFO), and (iv) 105 g/day of fish oil (FO). The fish oil was supplied in a proprietary product called Omega-3 Supplement which is a mixture of marine oils and an extracted oilseed meal and contains 500 g/kg of oil. The oils were fed in a concentrate mixture, which was offered at a rate of 3.0 kg/cow per day. The production of the cows was measured for 54 days and the milk fatty acid composition was determined on day 0 (immediately before the supplements were introduced) and on days 14, 28 and 42 after the treatments were imposed. Supplementation increased the yield of milk (P < 0.01), protein (P < 0.05) and lactose (P < 0.001), decreased milk fat (P < 0.05) and protein (P < 0.01) concentrations and increased (P < 0.01) lactose concentration. Type of oil did not significantly affect any production variable. The concentration of C18:1 trans 9 + C18:1 trans 11 (mainly C18:1 trans 11) (P < 0.001) and C18:2 cis 9, trans 11 CLA (P < 0.01) were greater on supplemented treatments than on P and the concentration of both were greater (P < 0.05) on FO than on SO. The results confirm that the concentration of C18:2 cis 9, trans 11 CLA can be increased further, from an already relatively high concentration in milk from pasture, by offering supplements containing a low level of fish oil either alone or in combination with sunflower oil. 相似文献
4.
Edenio Detmann Mrio F. Paulino Hilrio C. Mantovani Sebastio de C. Valadares Filho Cludia B. Sampaio Marjorrie A. de Souza Ísis Lazzarini Kelly S.C. Detmann 《Livestock Science》2009,126(1-3):136-146
This work aimed to parameterize the ruminal degradation of neutral detergent fibre (NDF) from low-quality tropical forage using Michaelis–Menten kinetics. The intake, rumen outflow (L), fractional degradation rate (kd), discrete lag (LAG) and effective degradability (ED) of NDF, and the microbial flow of nitrogenous compounds into the small intestine (Nmic) were assessed in two 5 × 5 Latin square experiments by using five Holstein × Zebu heifers cannulated in the rumen. The experiments were carried out sequentially and the treatments were formed by increasing the level of supplementation with nitrogenous compounds. A low-quality signal grass (Brachiaria decumbens) hay was used as roughage. The nitrogen supplement was a mixture of urea, ammonium sulfate and albumin, at the ratios of 4.5:0.5:1.0, respectively. The crude protein contents in the diets ranged from 51.9 to 136.3 g/kg of dry matter. The rumen ammonia nitrogen (RAN) concentration was used as an independent variable. The NDF intake, L and Nmic showed a quadratic pattern (P < 0.05) as a function of RAN concentration, and the critical points (maximum responses) were observed with 15.17, 16.28, and 14.52 mg of RAN/dL of rumen fluid, respectively. On the other hand, ED and LAG presented a linear-response-plateau (P < 0.05) according to the RAN concentration, with break points close to 8 mg/dL for ED (maximum estimate) and LAG (minimum estimate). The RAN concentrations to optimize NDF degradation and intake were defined as 8 and 15 mg/dL, respectively. This difference between estimates appears to be due to a better adequacy of the metabolizable protein:metabolizable energy ratio in the animal metabolism, which increases the animal intake even after the rumen NDF degradation has been optimized. This observation was supported by Nmic pattern. An adapted Michaelis–Menten model was applied to the data, where RAN was the independent variable and kd the dependent variable. The relationship between these variables was found to be significant by using the Hanes–Woolf plot (P < 0.01). Based on this model, the rate of NDF degradation as a function of RAN concentration indicates that fibre degradation in the rumen could be considered a second order process. In this context, the RAN concentration of 8 mg/dL was assumed as the limit where zero order (below limit) and first order (above limit) reactions become predominant for NDF degradation in the rumen. 相似文献
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西杂哺乳犊牛补饲方法试验报告 总被引:2,自引:0,他引:2
本研究选用44头10日龄西杂二代犊牛,随机分成试验组和对照组,试验组定时定量补饲饲配合饲料,且喂以干麦草和混合料,研究犊牛增重效果。结果表明,在补饲人,试验组和对照组的平均日增重分别为838和487g;头均补饲草料量无显著差异;头均盈利分别为788和476元。试验组件和出栏时间比对照组提前增年至一年。西杂占在哺乳期积累补饲培育,具有良好的增重效果和明显的经济效益。 相似文献
8.
Granzin BC 《Tropical animal health and production》2006,38(2):141-150
An experiment (108 days) was conducted to examine effects of cooling and forage supplementation on the performance of grass-fed,
early lactation Holstein cows in a coastal, subtropical environment during summer. When the temperature–humidity index (THI)
between 09:00 and 14:00 was < 72, cows grazed pastures containing shade. When THI reached 72 during this time, the following
treatments were imposed: pasture (P), cows remained in paddocks; feedpad (FP), cows were moved to a shaded feedpad with sprinklers;
feedpad plus hay (FPH), as for FP and fed 3 kg dry matter/cow per day of lucerne hay. When intervention occurred (55 days),
average THI (09:00–15:00) was 78 ± 0.6; mean cow rectal temperatures for FP and FPH were lower than for P (−1.0∘C and −0.9∘C, respectively); respective daily yields of milk and protein per cow were higher (p < 0.06) for FPH (22.7 L; 666 g) than for FP (21.1 L; 609 g) and P (20.9 L; 600 g). It was concluded that the energy intake
of Holstein cows in this environment is a greater limitation to milk production than intermediate heat loads. Supplementation
with lucerne hay during these conditions will increase milk yield. Using sprinklers in addition to shade will improve cow
comfort, but will not necessarily improve milk yield. 相似文献
9.
Reintroduction of captive-bred individuals for supplementation or re-establishment of wild populations has become increasingly important to prevent the extinction of many endangered species. Despite the importance of reintroductions for conservation biology, few studies have empirically evaluated the potential impacts of reintroductions of naïve organisms on disease outbreaks in native wild populations. Here, we use a model organism, the guppy (Poecilia reticulata) and its ubiquitous parasite (Gyrodactylus turnbulli) to evaluate: (i) the most effective release procedure (i.e. en masse vs. gradual release) that minimises host mortality and parasite load, (ii) the effect of pre-exposure to the parasite on host susceptibility, and (iii) the potential advantage of removing the most susceptible individuals before release. We could not detect a statistically significant difference in host survival rates between release protocols and pre-exposure regime. However, the parasite population went extinct significantly more often when pre-exposed fish were released. Furthermore, the parasite load of individual guppies by the end of the reintroduction was significantly lower in treatments where fish had been pre-exposed to parasites than in treatments with naïve guppies. Additionally, pre-exposure of hosts provided important information about their level of resistance when reintroduced. These findings suggest that pre-exposure to native parasites could be beneficial for the survival rate of captive-bred animals when reintroduced in the wild. We discuss the practicalities of these potential release strategies. 相似文献
10.
有机镁饲用时间对肉仔鸡抗氧化机能的影响 总被引:3,自引:0,他引:3
研究有机镁的不同饲用时间对肉仔鸡生长性能和抗氧化机能的影响。试验共使用 4 5 0只肉仔鸡 ,分成 5个处理 :处理 1(对照组 )、处理 2 ,3,4 ,5 ,分别在第 7,6 ,5和 4周开始使用有机镁日粮。试验结果 :最后 4周使用有机镁有降低肝脏和心脏MDA含量的趋势。使用有机镁可显著提高肝脏的TAOC(P <0 .0 5 ) ,并表现出对使用时间的依赖性。最后 2周使用有机镁可显著提高心脏TAOC。有机镁的使用显著提高了脾脏GSH Px的活性 ,并表现出对使用时间的依赖性。处理 3,4和 5肌肉的CAT活性显著提高 (P <0 .0 5 )。最后 3周使用有机镁显著提高脾脏CAT的活性 (P <0 .0 5 )。使用有机镁显著提高心脏GSH水平 相似文献