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931.
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933.
Ahmed Mohamed Fouad HebatAllah Kasem El-Senousey Dong Ruan Shuang Wang Weiguang Xia Chuntian Zheng 《Journal of animal physiology and animal nutrition》2021,105(6):1146-1153
Many studies have shown that productivity, immune system, antioxidant status, and meat and egg quality can be optimized by dietary supplementation with amino acids that are not usually added to poultry diets. Understanding the effects of these amino acids may encourage feed manufacturers and poultry producers to include them as additives. One of these amino acids is tryptophan (Trp). The importance of Trp is directly related to its role in protein anabolism and indirectly related to its metabolites such as serotonin and melatonin. Thus, Trp could affect the secretion of hormones, development of immune organs, meat and egg production, and meat and egg quality in poultry raised under controlled or stressed conditions. Therefore, this review discusses the main roles of Trp in poultry production and its mode (s) of action in order to help poultry producers decide whether they need to add Trp to poultry diets. Further areas of research are also identified to address information gaps. 相似文献
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935.
Dietary Threonine Needs for Growth and Immunity of Broilers Raised Under Different Litter Conditions
《The Journal of Applied Poultry Research》2007,16(4):574-582
Two studies were conducted simultaneously and evaluated the Thr needs of male Ross × Ross 708 broilers. Broilers in the 2 studies were reared under 2 litter conditions: new (NL) vs. used built-up soft wood shavings (BL). Separated by a center aisle, all floor pens from 1 side of the close-sided house contained NL, whereas the opposite side contained BL. Broilers received common diets up to 21 d and then were fed 1 of 6 total dietary Thr levels that ranged from 0.51 to 0.86% total Thr until d 42. At 42 d, birds were processed. A subsample of birds from each experimental unit corresponding to either the 0.51 or 0.72% Thr treatments was taken, immune function was quantified, and lymphoid organs were weighed. Results for live performance and carcass traits are in close agreement with previously reported values in the literature. Quadratic responses were observed for BW gain, feed conversion, and carcass and breast meat absolute and relative weights. Depending on the variable, these responses were maximized from 0.71 to 0.74% Thr when broilers were raised on NL and from 0.73 to 0.78% Thr when broilers were raised on BL. Low Thr (0.51%) was without effect on most immune parameters. However, low Thr decreased relative thymus weight and increased monocyte NO production in built-up and new litter environments, respectively. 相似文献
936.
鸭免疫H5N1亚型禽流感油乳剂灭活苗的免疫动态研究 总被引:2,自引:0,他引:2
本研究用不同剂量禽流感H5N1油乳剂灭活疫苗对各种周龄肉鸭、种鸭进行免疫接种,检测其相应的HI抗体水平,用酸性α-醋酸萘酯酶(ANAE)反应标记淋巴细胞的细胞化学方法测定其外周血中T、B淋巴细胞比值.探索肉、种鸭体液免疫和细胞免疫动态规律,为免疫防制禽流感制定最佳免疫程序提供科学依据.研究结果表明免疫接种小鸭,1周龄免疫接种效果不良,2、3周龄二次免疫效果优于2周龄一次免疫.种鸭对禽流感免疫应答反应良好;雏鸭H5N1母源抗体在出雏后3日龄达到峰值,5日龄开始下降,直至19日龄消失. 相似文献
937.
《The Journal of Applied Poultry Research》2006,15(1):122
The PSA Informal Nutrition Symposium of 2005 provided excellent lessons in many areas related to the dynamics of the digestive system. The following are brief comments about the 5 outstanding presentations.Doug R. Korver explored the similarities between the avian and mammalian gut immune functions [1]. It is of critical interest that activation of the immune system will divert nutrients from production functions.Guillermo Tellez emphasized the importance of understanding the complexity of the gut microflora [2]. Such an understanding could lead to effective management of microorganisms in the digestive system.Charles L. Hofacre reviewed the importance of certain ionophores in playing a beneficial role in competitive exclusion of some bacteria in the digestive system and reducing the risk of necrotic enteritis [3].Edwin T. Moran, Jr., addressed the interrelationships between the anatomy, microbes, and fiber with special emphasis on the comparisons between the small and large intestines [4]. Different strategies are used by the digestive system to manage nutrient absorption at the intestinal surfaces. Such strategies were explored comprehensively.Elizabeth A. Koutsos elaborated on the value of using new technologies in studying the bacterial communities rather than focusing on individual microorganisms [5]. Discovering and pinpointing interactions among the intestinal ecology, anatomy, microflora, and nutrition will ultimately help reach a meaningful understanding. 相似文献
938.
诱惑侦查作为一种实效性极强的侦查方式日益受到侦查实践部门的青睐。诱惑侦查带有一定程度的欺骗性,与刑事追诉中的基本价值追求相矛盾,备受争议。各国在放松对诱惑侦查禁止性规定的同时,又严格加以限制,力图充分利用这一可能严重侵害公民合法权益的侦查手段,平衡价值上的冲突。诱惑侦查所获证据之效力应坚持有限可采性,侦查人员实施的犯罪行为之刑事责任的证据应坚持有限豁免性。 相似文献
939.
采用体外淋巴细胞转化试验研究谷氨酰胺(Gln)及丙氨酰谷氨酰胺(Ala-Gln)对早期断奶仔猪肠系膜淋巴结细胞增殖的影响。摘取28日龄断奶仔猪肠系膜空、回肠淋巴结,分离淋巴细胞,接种于含不同浓度Gln或Ala-Gln的培养液中37℃培养72h后,四甲基偶氮唑盐(MTT)法测定细胞增殖。Gln浓度为2mmol/L时,淋巴细胞刺激指数最大;Ala-Gln浓度为1mmol/L时,淋巴细胞刺激指数最大。增加Gln或Ala-Gln浓度并没有增加其效应。本试验表明Gln和Ala-Gln均可以促进丝裂原植物凝集素(PHA)刺激的淋巴细胞增殖,在一定浓度范围内Ala-Gln与Gln具有相似的作用。 相似文献
940.
《The Journal of Applied Poultry Research》2006,15(1):123-135
The digestive tract of the chicken is a major site of pathogen exposure. Although the bird has a multifaceted set of tools to prevent or resist infection, any activation of the immune system can divert nutrients away from production. Therefore, prevention of pathogenic exposure is preferred. However, it is unlikely that the bird can escape exposure to all pathogens during its life, thus the ability to respond to immunologic challenges is essential. The immune system of birds is similar to that of mammals in terms of structure and function, although some differences do exist, particularly in regulatory aspects. The innate immune system responds nonspecifically to foreign molecules and is essential for the induction of the specific (acquired) immune response. Cells of the innate immune system include macrophages, dendritic cells, heterophils, and natural killer cells. The acquired immune response involves recognition of a specific antigen and response by lymphocytes. Cytotoxic T lymphocytes are especially effective at inducing cells infected with intracellular pathogens to undergo apoptosis. Helper T lymphocytes increase the effectiveness of innate immune cells in combating extracellular pathogens and are also essential for activating B lymphocytes, which produce antibodies specific to the invading pathogen. All aspects of the immune system function together, although one aspect will often dominate, depending on the type and severity of the infection. This paper reviews the basics of avian immune function in general and discusses the immune system in the digestive tract in particular in birds. The consequences of activation of the immune system are presented.Currently, growth-promoting antibiotics are not used in poultry in many countries; the North American industry may be moving in that direction as well, either through legislation or consumer pressure. Several nonantibiotic means of manipulating the immune system to prevent the health- and performance-suppressing effects of immune system activation are presented here. 相似文献